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Biodegradation of potentially harmful compounds in wastewater treatment

Aalto University School of Engineering
Pia Ahlgren

BIODEGRADATION OF POTENTIALLY HARMFUL COMPOUNDS IN
WASTEWATER TREATMENT

Master's Thesis submitted for examination for the degree of Master of Science in Technology. Espoo 25.4.2012 Supervisor: Professor Riku Vahala Instructor: Lic.Sc.(Tech.) Pirjo Rantanen AALTO UNIVERSITY ABSTRACT OF THE MASTER'S THESIS SCHOOLS OF TECHNOLOGY PO Box 11000, FI-00076 AALTO http://www.aalto.fi Author: Pia Ahlgren Title: Biodegradation of potentially harmful compounds in wastewater treatment School: School of Engineering Department: Civil and Environmental Engineering Professorship: Water and Wastewater Engineering Supervisor: Professor Riku Vahala Instructor: Lic.Sc.(Tech.) Pirjo Rantanen To study Potentially Harmful Compounds (PHCs) in the environment and their fate in Wastewater Treatment Plants (WWTPs) is a growing area of interest among researchers. Persistent Organic Pollutants (POPs) and Endocrine Disruptive Compounds (EDCs) are a concern together with Pharmaceuticals and Personal Care Products (PPCP). While advanced treatments are being considered, the fate of compounds in activated sludge is important to understand. Biodegradation is the only way of entirely removing PHCs in WWTPs and stopping them from ending up in the environment. In this thesis a laboratory scale Sequencing Batch Reactor (SBRs) with four parallel reactors was built and the operation optimized. Sludge from the Suomenoja WWTP was used to start the reactors and they were then fed with synthetic wastewater. The operational conditions were chosen to be typical values in Finnish WWTPs. A marker compound, ibuprofen, was chosen to be studied in the reactors. The objective was to verify laboratory procedures and obtain a primary biodegradation rate and biodegradation rate constant of the compound. Ibuprofen is a non-steroidal acidic anti-inflammatory drug that is largely used in Finland and found in environmental waters as well as in WWTPs. The synthetic wastewater was spiked with ibuprofen on four occasions. Samples from the reactors were taken at different times during aeration to analyze the ibuprofen concentration. This way the biodegradation rate and biodegradation rate constant (kbiol) was determined for ibuprofen in the SBRs. The average biodegradation of ibuprofen in the reactors was 30-50%. A kbiol value of 1.9l/gSS/d was obtained. The values obtained in the study were in good agreement with previous studies. The slightly lower value for the constant could possibly be explained by the high F/M-ratio. Further research on the biodegradation mechanisms and the effect of different treatment conditions are needed to optimize the removal of ibuprofen. Also the accuracy of the analyses needs to be improved. Language: English Number of pages: 14+91+10 Keywords: biodegradation, ibuprofen, PHC, SBR, wastewater treatment,

AALTO-UNIVERSITETET SAMMANDRAG AV DIPLOMARBETE HÖGSKOLORNA FÖR TEKNIK PB 11000, FI-00076 AALTO http://www.aalto.fi Författare: Pia Ahlgren Titel: Biologisk nedbrytning av potentiellt skadliga föreningar i avloppsrening Högskola: Högskolan för Ingenjörsvetenskaper Institution: Institutionen för samhälls- och miljöteknik Professur: Vatten- och avloppsteknik Övervakare: professor Riku Vahala Handledare: TkL Pirjo Rantanen Att studera potentiellt skadliga föreningar i naturen och i avloppsreningsverk har under senaste åren blivit en prioritet bland forskare. Långlivade organiska föreningar, så kallade POPs, föreningar som stör det endokrina systemet (EDCs), läkemedel och ämnen i hygienprodukter och kosmetika är ett växande bekymmer. Att studera dessa ämnens öde i avloppsreningsverk, speciellt aktivslamprocessen, är viktigt före man beslutar ifall mer avancerade reningsmetoder är nödvändiga att implementera. Biologisk nedbrytning är det enda sättet att totalt eliminera potentiellt skadliga föreningar i avloppsreningsverk och hindra dem ifrån att hamna i naturen. I detta diplomarbete byggdes ett satsvis biologiskt reningsverk (SBR) i laboratorieskala med fyra parallellreaktorer och deras funktion optimerades. Processen startades med slam från Finno avloppsreningsverk varefter reaktorerna matades med syntetiskt avloppsvatten. Förhållanden, där reaktorerna opererade, var valda för att bäst representera förhållanden i finska avloppsreningsverk. En förening, ibuprofen, valdes för att fungera som markör och studerades i processen. Syftet var att verifiera provtagningsmetoderna i laboratoriet och få preliminära värden för biologisk nedbrytning av ibuprofen. Ibuprofen är en icke-steroid antiinflammatorisk medicin som används allmänt och som sedan har hittats i vattendrag och i avloppsreningsverk i Finland. Ibuprofen tillsattes i det syntetiska avloppsvattnet fyra gånger under studieperioden. Sampel från reaktorerna togs vid olika tider under luftningsfasen för att sedan kunna bestämma den biologiska nedbrytningen och nedbrytningskoefficienten. Ibuprofen nedbröts i medel 30-50% och därav kunde en biologisk nedbrytningskoefficient (kbiol) på 1,9l/gSS/d bestämmas. Dessa värden stämmer bra överens med värden från tidigare studier. Att nedbrytningskoefficienten dock var lite lägre än i andra studier, kan ha berott på den höga slambelastningen. Fortsatta studier på mekanismer bakom biologisk nedbrytning av ibuprofen behövs för att ytterligare optimera dess eliminering i avloppsreningsverk. Det krävs även bättre analysnoggrannhet för att erhålla exakta värden på nedbrytningen. Datum: 25.4.2012 Språk: Engelska Sidantal: 14+91+10 Nyckelord: Avloppsrening, biologisk nedbrytning, ibuprofen, SBR, skadliga föreningar This study was made in the Water Engineering research group of the Civil Engineering Department. It was a pre-study for future research to be made in the Water Engineering research group. The study was funded by Maa- ja Vesitekniikan Tuki ry and their contribution is greatly appreciated. First I would like to thank prof. Riku Vahala and Lic.Sc.(Tech.) Pirjo Rantanen for making this thesis possible. The advice and support I got from Pirjo during the whole process was invaluable. A special thank go to the entire staff at the Water Laboratory, especially to Aino Peltola and Ari Järvinen for helping me during the experiments. I would also like to thank Dr Michela Mulas and Lic.Sc.(Tech.) Henri Haimi for providing me with tips and materials for my work. All of this would not have been possible without the support from my family. Thanks go also to my friends who provided me with a memorable time as student and much needed relief from my studies. Lastly I would also like to express my gratitude to Tomi for his patience and support. Contents
Literature part
Experimental Part
Appendix I Results from analyses Appendix II Planning and operating a pilot scale Sequencing Batch Reactor (SBR) Appendix III CD with pictures of the Sequencing Batch Reactor Symbols and legends

Biological Oxygen Demand Chemical Oxygen Demand Food per Mass Ratio g BOD/ g MLSS /dg COD/ g MLSS/d Hydraulic Retention Time Mixed Liquir Suspended Solids Mixed Liquir Volatile Suspended Solids mass/volume Sludge Volume Index Solids Retention Time Total Phosphorous Describes the ability to ionize or dissociate to Dissociation constant Biodegradation rate constant Describes the biodegradation potential Sorption coefficient Describes the sorption potential Octanol-water-partition coefficient Describes lipophilicity of a compound Defined Daily Dose Endocrine Disruptive Compound Hexabromocyclododecane High Performance Liquid Chromatography Hydraulic Retention Time Liquid Chromatography Long-Chain Chlorinated Paraffarin Membrane Bioreactor Medium-Chain Chlorinated Paraffarin Mass Spectrometry Nonylphenol Ethoxylate Polycyclic Aromatic Hydrocarbon Persistent, Bioaccumulative, Toxicity Prefluorinated Alkyl Compounds Perfluorooctanoic Acid Perfluorosulfonate Potentially Harmful Compound Persistent Organic Pollutant Pharmaceuticals and Personal Care Products Quantitative Structure-Activity Relationship Returned Activated Sludge Sequencing Batch Reactor Short-Chain Chlorinated Paraffarin Solid Phase Extraction Tetrabromobisphenol A Ultra Performance Liquid Chromatography Volatile Organic Compound Wastewater Treatment Plant List of Tables
List of Figures
1. Introduction
1.1 Background
Municipal wastewater has been treated for over a hundred years. In the beginning the priority was to remove organic materials, suspended solids and pathogens. The objective of nutrient removal in Wastewater Treatment Plants (WWTPs) was raised, when it was found that the large quantities of nutrients that are led to environmental waters increase the growth of algae. The aim was to improve water quality for leisure purposes. Although these goals have not been met in all wastewater treatment plants, in the industrialized world the focus has now been shifting towards other Potentially Harmful Compounds (PHCs) in wastewater. Pharmaceutical residues, pesticides and compounds that are used in solvents, paints and cleaning agents, are all found in environmental waters. The biggest source of harmful compounds in drinking water, rivers, oceans and lakes is believed to be the effluents from WWTPs. These compounds can be mutagenic, carcinogenic, toxic and hormone disrupters. When released into the environment, PHCs may harm both organisms living in nature and humans. A danger is also that the compounds pass into drinking water supplies. It is important to find out what PHCs are in our waters and how we can eliminate these in wastewater treatment. The challenge is to detect many different kinds of compounds at low concentrations. The compounds that have been described in this study are a selection of different chemicals that lately have raised concerns due to their presence in waters, their toxicity and/or are being largely used in society. The compounds in this study are found, in varying degrees, in WWTPs. 1.2 Objectives and scope of study
The literature part of the study concentrates on collecting the latest information about PHCs in municipal wastewaters. The experimental part will focus on getting a laboratory scale sequencing batch reactor (SBR) to operate. The feasibility of the reactors' operation and sampling procedures are verified by checking mass balances with the help of a marker compound. A final objective of the study is to estimate a primary biodegradation rate and biodegradation rate constant of a marker compound in 2. Wastewater treatment
Municipal WWTPs are built to treat wastewater that has been produced under normal household conditions. Urine, feces and grey water resulting from washing and bathing are the main sources of municipal wastewater. Industrial wastewaters can also, by agreement, be led into municipal WWTPs. Industrial wastewaters need in many cases pretreatment before being led into municipal WWTPs. However, many compounds in different forms end up in WWTPs. The chemical structure defines how compounds can be removed. They can be solids and water or fat soluble. It is preferable to separate as much of the solids as possible before continuing to the next stages of the wastewater treatment process. The design of WWTPs varies. Biological, chemical and membrane treatments can all be used separately or combined. (Swedish Environmental Protection Wastewater can consist of many different compounds in different concentrations depending on location, time, season and weather conditions. Conventionally wastewater is seen to consist of suspended solids, biodegradable organics, nutrients (nitrogen and phosphorus), pathogens, heavy metals, colloidal and dissolved solids, Volatile Organic Compounds (VOC) and odors. The function of WWTP's is to remove these from wastewater so that they are not released into the environment. Biological Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) are used to measure the amount of organic matter in the wastewater. (Metcalf & Eddy, 2003; Bitton, 2005) The different treatment steps in a typical WWTP can be divided into preliminary treatment, primary treatment, secondary treatment, advanced/tertiary treatment and solids treatment and disposal. The objective of preliminary and primary treatment is to remove solids by mechanical treatment and by settling or floating. Secondary and advanced treatments are mostly biological and/or chemical treatment processes that remove organics, nutrients, pathogens, parasites and toxic compounds from the water. (Vesilind, 2003; Metcalf & Eddy, 2003; Bitton, 2005) In Figure 1 the treatment process of the Suomenoja WWTP is illustrated.

Secondery sedimentation tanks 5…10 21.
Sand - and grit storage Returned activated sludge Sludge thickening Heating of the thickened sludge Reserved for tertriary treatment Primary sedimentation Thickening of digested sludge Activated sludge chambers 1…4 Centrifugation of sludge Activated sludge chambers 5…4 Secondery sedimentation tanks 1…4 20.
Figure 1 Operation of Suomenoja WWTP. (Helsinki Region Environmental Services Authority, 2011)
2.1 Biological treatment
In a municipal WWTP the objective of biological treatment is to biodegrade constituents into acceptable end products, capture solids into biological flocs or biofilm and to remove nutrients and other organic particulates. Microorganisms in the biological treatment oxidize organics into more simple constituents. The microorganisms are also used to remove nitrogen through nitrification and denitrification. Biological treatment can be divided into aerobic, anaerobic and/or anoxic sections. (Metcalf & Eddy, 2003) Activated sludge process
The activated sludge process is used in many WWTPs as a secondary treatment. The principle is that activated sludge oxidizes organic matter into CO2 and H2O, NH4 and new biomass under aerobic conditions. The biomass forms suspended solids flocs in the tank, which are removed by settling. Mixed Liquor Suspended Solids (MLSS) is used as a measure of the solids content of an activated sludge tank. It describes the amount of organic and mineral suspended solids in the tank, which includes microorganisms. Nitrification is the process where ammonia is oxidized into nitrite and then nitrite is oxidized into nitrate. This reaction is needed in a WWTP in order to remove ammonia due to toxicity and total nitrogen due to eutrophication effects. Because aerobic autotrophic bacteria, the nitrification bacteria, grow more slowly than heterotrophic bacteria, nitrification needs a longer Solids Retention Time (SRT). Heterotrophic bacteria are responsible for organics removal. The nitrification steps are shown in Equation 1. (Metcalf & Eddy, 2003) In order to complete the nitrogen removal, which starts with nitrification, denitrification needs to take place. Denitrification means the reduction of nitrate into nitric oxide, nitrous oxide and nitrogen gas. The denitrification steps are shown in Equation 2. (Metcalf & Eddy, 2003) Phosphorus removal
Phosphorus removal can be achieved both biologically and by chemical addition. The basic idea is to incorporate phosphorus into suspended solids. This can happen either by microorganisms or precipitation chemicals such as iron or aluminum salts. The chemical reactions for precipitation with aluminum and iron can be seen in Equations 3 and 4. (Metcalf & Eddy, 2003) Biological phosphorus removal can be achieved with many different methods. The biological phosphorus removal processes include, in the biological suspended growth process, an aerobic zone followed by an anaerobic zone. The biological removal of phosphorus can also be achieved by modifications of this basic principle. (Metcalf & 3. Potentially harmful compounds in wastewater
3.1 History
In the 1950s concerns grew over the effects of pollutants in nature. Birds and raptors were found dead or unable to reproduce. When the animals were tested, high amounts of the pesticide DDT was found in their bodies. DDT and mercury were used widely in agriculture as insecticides and as prevention of fungal growth on seeds. High levels of mercury and DDT were also found in agricultural produce and fish, which led to growing concerns over their effects on human health. In 1966 a Swedish researcher found high concentrations of Polychlorinated Biphenyls (PCBs) in the environment. These compounds have been produced since 1929. In the 1960s and 1970s many of these toxic pollutants were banned from production and use. These are however still found in the environment today. (Swedish Environmental Protection Agency, 2008; Stockholm Convention, 2011) 3.2 Current research on potentially harmful compounds in wastewater
Municipal WWTPs are not generally designed to remove pharmaceuticals or other PHCs from wastewaters. The use of harmful compounds can be prohibited by governments and thus eliminating them from wastewaters and preventing them from ending up in the environment. (Swedish Environmental Protection Agency, 2008) But to study the fate of these compounds in WWTPs is also important when trying to control their concentrations in environmental waters. (Urase & Kikuta, 2005) One of the most important tasks in water research at the moment is to determine what compounds are harmful and in what concentrations. The problem is that different organisms can react to a compound in different ways. A concentration of a compound that is toxic to one organism can be safe to another. Synergy effects of different mixtures of compounds and their metabolites are also hard to determine or rule out. Many different things need to be taken into consideration when assessing the risks that different compounds pose to the environment. Assessments and measurements for PHCs that should be made are listed below. (Swedish Environmental Protection  Assessment of emission sources and levels  Monitoring of levels in environment and organisms, including humans  Exposure assessments  Assessments and test on effects on organisms  Stability of compound (bioaccumulation and half-life)  Determination of harmful levels In the assessment of the level of threat a compound poses and in what quantities, Quantitative Structure-Activity Relationship (QSAR) can be used. This model is a way of calculating the behavior of an unknown compound by comparing its molecular and physical properties to known compounds. (Swedish Environmental Protection Agency, 2008) The QSAR model has also been used to evaluate the biodegradation of pharmaceuticals. (Urase & Kikuta, 2005) In the EU the documentation and knowledge of compounds is growing due to the REACH-regulation. All chemical products need to be registered and evaluated, and if they pose any risk their use can be restricted. Therefore it is known what new chemicals might end up in WWTPs. (Swedish Environmental Protection Agency, 2008) In 2001 the Stockholm Convention was adopted to influence the problem of Persistent Organic Pollutants (POPs). The Stockholm convention is a global treaty under the United Nations Environmental Protection Agency. Originally twelve POPs were adopted, including DDT and PCBs. In 2009 nine new chemicals were added to the list in the treaty. Now three more chemicals are considered to be added; chlorinated naphthalene, hexablorobutadine and pentachlorophenol. Control measures to reduce the amount of the brominated flame retardant Hexabromocyclododecane (HBCD) and Short Chain Chlorinated Paraffins (SCCPs) are also being evaluated. (Stockholm Convention, As POPs are a priority in international agreements, they are now studied more intensely. POPs are biodegraded very slowly and they bioaccumulate in the environment when released. They are believed to be toxic, carcinogenic and endocrine disruptive. Because of their chemical composition they have been shown to accumulate in the fat tissue of living organisms. They do not volatilize, they have a large molecular weight and are hydrophobic. (Malmi & Mannio, 2008) Many of the compounds that have recently started to worry researchers are compounds with endocrine disrupting tendencies. As early as in the 1930s there have been reports of natural and synthetic compounds that can mimic endogenous hormones in animals and disturb the endocrine system. (Liu, et al., 2009) In the 1990s hermaphroditic fish were found in sewage treatment lagoons. (Johnson, et al., 2005) Endocrine Disruptive Compounds (EDCs) are among the most harmful of man-made compounds as they disturb the reproduction of aquatic animals. EDCs have also been linked to human sperm quality and cancers such as breast-, prostate- and testicular cancers. EDCs have either estrogenic or androgenic activity and can be harmful even in very low concentrations. (Liu, et al., 2009) Many different types of compounds have been observed to have endocrine disruptive tendencies (pharmaceuticals, personal care products, pesticides, plasticizers, industrial chemicals etc.). These compounds, that have the ability to mimic or modify endogenous hormones, are called xenoestrogens. (Combalbert & Hernandez-Raquet, 2010) The endocrine system is very complex, which can explain why so many different compounds have shown to disturb it. (Bolong, et al., 2009) Natural and synthetic hormones are the most potent estrogenic compounds; these are discussed in Chapter 4.2. 3.3 Removal of potentially harmful compounds in wastewater
treatment plants
There are four different things that can happen to organic compounds in a conventional WWTP. A compound can break down (biodegrade), sorb to sludge, volatilize or end up in the effluent. Compounds can break down completely (mineralize) or turn to other compounds. Different operational conditions have been found to influence the biodegradation of a compound. Some compounds biodegrade better with a long SRT and the biodegradation is usually faster when a high concentration of the compound is present. (Swedish Environmental Protection Agency, 2008) The biological transformation of compounds is dependent on many different things. A biodegradation rate constant can be used to describe the biological transformation. But the compounds sorption potential has also a big impact on its fate; the sorption coefficient kd describes this. Compounds with high kd values need a longer SRT to accomplish their biodegradation. (Suárez, et al., 2008) Xenobiotic compounds are particularly persistent to biodegradation and microbes. They are often halogenated organic compounds that are especially hard for microbes to degrade. Halogenated organic compounds include halogenated hydrocarbons, halogenated aromatics, pesticides and PCBs. (Bitton, 2005) 3.3.1 Biodegradation
Biodegradation is biological degradation by either aerobic or anaerobic microorganisms that leads to the reduction of a parent compound or metabolite. WWTPs have a huge potential to reduce PHCs and their metabolites via biodegradation. Biodegradation will mostly occur during secondary treatment in the wastewater treatment process. This is where the compounds will be subjected to the most activity by microorganisms. The biodegradability of a compound is largely dependent on its structure. Unbranched compounds with short side chains are more likely to biodegraded than compounds with a large number of branched side chains. (Jones, et al., 2005) Many of the compounds, foreign to the biological systems, that have been introduced to the environment during the last century are not readily biodegradable. Many factors contribute to the resistance to biodegrade. Not only the chemical structure but also environmental factors, toxicity to microbes, unavailability of nitrogen and phosphorus, low substrate concentration and unavailability of the substrate due to sorption. (Bitton, Two main mechanism of biodegradation are possible. Co-metabolism takes place when a compound biodegrades only when other organic compounds are present and are acting as substrate for the microorganisms. The other mechanism is called catabolic metabolism and it takes place when the compound in itself can be the only source of substrate for the microorganisms. (Stasinakis, et al., 2005) Biodegradation is also highly dependent on the microbial communities. If the communities are not adapted to the compound they start to select the microbes that can degrade the compound. This is why a period of acclimation is sometimes needed before the foreign compound starts to biodegrade. (Bitton, 2005) Even though there have been research in microorganisms' role in the biodegradation of compounds, it is still unclear which have the main responsibility in degrading which compound. Therefore it remains hard to optimize WWTPs for PHCs removal. (Roh, et al., 2009) Biodegradation of compounds in WWTPs can be described by pseudo first order reaction illustrated in Equation 5. (Ternes, 2004) Ci is the concentration of the soluble substances of the compound, kbiol is the kinetic constant (biodegradation rate constant) and SS is the Suspended Solids concentration. More about rate equations is described at the end of this chapter. Biodegradability depends not only on the constants but also the diversity and total share of the biomass. Typically the biodegradation rate constant in a conventional WWTP mean the following removal rates: (Ternes, 2004) kbiol < 0.1 = no removal due to biodegradation 0.1< kbiol < 10 = removal due to biodegradation is dependent on treatment kbiol > 10 = at least 95% removed by biodegradation Many studies that have measured the biodegradation of compounds have not studied the metabolites that may form. By only studying the parent compound and not metabolites that can be even more harmful than the original compound, important facts may go undetected. Biodegradation does not explain if a compound mineralizes or transforms to metabolites. (Fatta-Kassinos, et al., 2011) Rate equations
As it is not possible on a molecular level to observe and see reactions taking place, models to describe the reactions must be made. Rate equations can be used to describe reactions in batch processes. When a reaction cannot happen in both directions, the reaction is seen as irreversible. For irreversible reactions, the reaction order and a reaction rate constant can be determined. (Solen & Harb, 2011) To determine the reaction order and rate, the concentration versus time data need to be analyzed. For this different methods can be used. (Fogler, 2009) One way to determine the reaction order and rate equation is to guess (or know it beforehand) and then integrate the equations that are used to describe the system. When the reaction order is correct, the plot of the data will be linear. (Fogler, 2009) In a first order reaction: C0 is the concentration in the beginning and CA is the concentration at time t. This means that when ln(C0/CA) is plotted as function of time, the slope is linear. The reaction rate constant k is the slope of the line. In a second order reaction a plot of 1/CA against the function of time gives a linear slope. (Fogler, 2009) In a pseudo first order reaction, that is often used to describe the biodegradation of pharmaceuticals, a reaction that is initially second order is changed to first order as the other variable, the suspended solids concentration, can be considered to remain constant. (Fogler, 2009; Ternes, 2004) When the reaction rate/degradation constant, kbiol, is known, it is possible to calculate the relative amount degraded in a batch reactor with the Equation 7. Cout is the concentration at the end. (Ternes, 2004) The total biological transformation can be calculated with Equation 8. 3.3.2 Sorption
Compounds can either adsorb or absorb to sludge. Adsorption happens when ions bind or physically adhere to another molecule. For example negatively charged microorganisms in sludge have the ability to adsorb positively charged compounds. The chemicals ability to ionize or dissociate to aquatic phase can be characterize by ka (the dissociation constant). (Suárez, et al., 2008) Absorption is the reaction when molecules in a fluid enter another bulk phase. The tendency to absorb is related to the chemicals lipophilicity which can be described with kow (octanol-water partition coefficient). (Suárez, et al., 2008) For hydrophobic and positively charged ions, sorption is an important removal mechanism. The log kow value can be used to describe an organic compound's tendency to sorb to sludge. (Swedish Environmental Protection Agency, 2008) Log kow < 2.5, low sorption potential Log kow 2.5-4, middle sorption potential Log kow > 4, high sorption potential The sorption to sludge can also be described with the following equation: Where Ci, sorbed is the concentration of the compound that is sorbed to the sludge, kd, i is the sorption coefficient and Ci, soluble is the soluble concentration of the compound. 3.3.3 Volatilization /stripping
Many PHCs are able to evaporate to the atmosphere and stay there for various amounts of time. A compound's ability to evaporate is determined by its volatility. A volatile PHC can travel from the original pollution source and end up in another part of the world. (Swedish Environmental Protection Agency, 2004) Volatilization, or air stripping, transfers mostly VOC and ammonia from water phase into air phase. (Bitton, 4. Pharmaceuticals and Personal Care Products (PPCP)
4.1 Personal care products
Compounds used in personal care products have lately been frequently detected in water supplies. Personal care products, including fragrances, hygiene products, cosmetics and sunscreens may include compounds that have negative environmental effects and act as EDCs. (Suárez, et al., 2008) Personal care products consist of a lot of different compounds, including preservatives and antibacterial compounds, and these can cause negative effects both to the environment and the wastewater treatment process. Also sunscreen agents and musk's can contain PHCs. (Swedish Environmental Protection 4.1.1 Triclosan
Triclosan is used in many personal care products such as soaps, fabrics, creams and cleaners. It is used as an antibacterial agent and preservative and is present in most items that contain antibacterial properties. As the product has been dispersed, environmental waters have become polluted with the compound. The concern is, that the presence of triclosan in the environment will help form cross-resistance in pathogens and that the compound is toxic. Triclosan is believed to be an androgen and form chlorophenols with free chlorine during drinking water treatment. (Roh, et al., 2009) The properties of triclosan are presented in Table 1. Federle et al. (2002) studied the fate of triclosan in a conventional activated sludge WWTP. They observed that up to 85-95 % of the influent triclosan biodegraded and 1.5-4.5% sorbed to sludge. They concluded that triclosan was biodegradable in both high and low concentrations in activated sludge. They showed that acclimation of the microorganisms is crucial to the biodegradation of triclosan. They also concluded that triclosan did not disrupt the activated sludge processes in the WWTP, not even in high concentrations. (Federle, et al., 2002) Paxéus (2004) studied the removal of triclosan in five WWTPs in Europe. All the WWTPs used primary settling and activated sludge in their treatment. He observed that triclosan had high removal rates in WWTPs, with an average of 73% and the lowest removal of 58%. (Paxéus, 2004) It has also been experimentally proven that triclosan does not biodegrade under anoxic or anaerobic conditions. (Chen, et al., 2011) In a study made by Roh et al. (2009) the biodegradation of triclosan, bisphenol A and ibuprofen by ammonia-oxidizing bacteria was studied. They observed that triclosan was biodegraded by the ammonia-oxidizing bacteria Nitrosomonas europaea. But the test also indicated that, due to competitive behavior or toxicity effects, the presence of triclosan reduced nitrate production. (Roh, et al., 2009) Table 1 Properties of triclosan
Chemical structureMolecular weight Antibacterial agent Thomas et al . (2004) 4.1.2 Galaxolide (HHCB)
HHCB is a musk fragrance used in many personal care products. Of a large group of polycyclic musk's, HHCB is the most commonly used. It is also known by the names Abbalide, Pearlide and Chromanolide. HHCB is only produced in one factory in the EU (1000-5000 tons/year) but it is imported from outside the EU. (European Union-Risk Assesment Report, 2008) The properties of HHCB are presented in Table 2. HHCB is a growing interest to researchers as it is used in large quantities and has shown low biodegradability. A conclusive biodegradation rate of HHCB is not known. (European Union-Risk Assesment Report, 2008) Kupper et al. (2006) found that HHCB sorbed to the sludge 72% - 86 %; this seems to be the only way of removing the compound from wastewater. (Kupper, et al., 2006) In the POSEIDON project, the sorption to sludge was estimated to be about 80%. (Ternes, 2004) There has not been found any health risks for humans resulting from the use of HHCB. (European Union- Risk Assesment Report, 2008) HHCB has however shown to be an endocrine disrupter in fish. (Kupper, et al., 2006) Table 2 Properties of the musk HHCB
Chemical structureMolecular weight Suarez et al . (2008) Suarez et al . (2008) 4.2 Hormones
Studies have detected four main and potent estrogens in wastewater; E1 (Estrone), E2 (Estradiol), E3 and EE2 (17α-Ethinylestradiol). Of these, the three first are natural hormones and the last one is a synthetic hormone. E1 is a degradation product of E2 and therefore found in larger concentrations than E2 in the environment. EE2 is used as a contraceptive and in other hormone therapies. Although synthetic estrogens can be classified as pharmaceutical compounds, this chapter will only focus on estrogens. More of other pharmaceuticals can be found in Chapter 4.3. (Racz & Goel, 2010; Johnson, et al., 2005) Estrogens were concluded to be, in the POSEIDON project, the most important PPCP to study in WWTPs. (Ternes, 2004) The properties of E1, E2 and EE2 are presented in Table 3. Kidd et al. (2007) studied the fate of a fish population in a lake when the synthetic estrogen EE2 was added to a lake to the concentration of 5-6ng/l. They found large feminization of the fish population and other reproduction disturbing effects. Almost the entire fish population was extinct within the 7-year experimental period. This shows that the estrogens are very potent even in very low concentrations. (Kidd, et al., 2007) Most of the estrogen that is released into nature comes from humans and livestock. The amount of estrogen that a human excretes depends on a person's sex and age. Pregnancy increases the excretion of all estrogens. It has been calculated that the total human population excretes about 29.5t of estrogens a year. This does not include the 720 kg of synthetic hormones that is released to the environment due to hormonal contraception. The concentration of estrogens in influent wastewater can be between 1-700ng/l, depending on country and population structure. (Combalbert & Hernandez-Raquet, The fate of estrogens in WWTPs is dependent on chemical properties of the hormone, treatment plant type, processes and properties of the plant, and biological activity. WWTP parameters that have been shown to influence the fate of the estrogens are SRT, Hydraulic Retention Time (HRT), temperature, carbon load redox potential and floc size. Especially SRT has been proven to be an essential parameter. The longer SRT is linked to nitrification and a hypothesis is that nitrifying bacteria biodegrade estrogens. (Combalbert & Hernandez-Raquet, 2010) A long SRT also allows more slowly growing bacteria (including nitrifiers) and a more diverse bacterial community. (Racz & Goel, 2010) It has been experimentally shown that EE2 is degraded in nitrifying activated sludge even without an adaptation period. Some studies suggest that, while ammonia and nitrate are present in low concentrations in a WWTP, heterotrophic bacteria are responsible for estrogen degradation. (Combalbert & Hernandez-Raquet, 2010) Estrogens can also be subject of sorption after deconjugation. The fate of estrogens in WWTP is illustrated in Sorbed estrogens easily enter the nature again through sludge that is disposed in landfills or otherwise in the environment, that is why biodegradation is preferred as the best way to remove estrogens. (Racz & Goel, 2010) Although hormones have hydrophobic properties and should therefore sorb into sludge, it has been shown through mass-balance calculations that only 6-8% of the hormones sorb to sludge. The primary way to remove estrogens is through biodegradation. (Combalbert & Hernandez-Raquet, 2010) In activated sludge WWTP it has been recorded that estrogens are removed from the influent water 18-100%, depending on the plant and the type of estrogen. (Racz & Goel, 2010) In the POSEIDON project E1 and E2 were found to biodegrade over 95% in nitrifying activated sludge. EE2 was not found to be removed at low sludge ages but in nitrifying activated sludge the biodegradation was over 90%. EE2 was also found to sorb to sludge less than 5%. (Ternes, 2004) To understand the correlation between sorption and biodegradation of estrogens in WWTP, more study is needed. (Combalbert & Hernandez-Raquet, 2010) Two WWTPs were studied in Finland in 1999 by Johnson et al. (2005) for concentrations and removal rates of E1 and E2. They found up to 45ng/l E1 in wastewater influent in the Viikinmäki WWTP in Helsinki. The removal rate of E1 was estimated to be 94%. The treatment of wastewater in Viikinmäki WWTP consisted of an activated sludge process with an anoxic zone, chemical phosphorus removal and nitrification. During the sample period in June 1999 the temperature of the effluent water was 15°C, the organics removal 90-98% and the plant had a SRT of 19 days and a biological HRT of 8.8 hours. (Johnson, et al., 2005) Figure 2 Fate of estrogens in WWTPs and environment. (Racz & Goel, 2010)
Table 3 Properties of the estrogens E1, E2 and EE2.
Chemical structureMolecular weight Suarez et al . (2008) Combalbert et al . Suarez et al . (2008) Suarez et al . (2008) Chemical structureMolecular weight Suarez et al . (2008) Combalbert et al . Suarez et al . (2008) Suarez et al . (2008) Chemical structureMolecular weight Razc et al . (2009) Ternes (2004)Combalbert et al. Suarez et al . (2008) 4.3 Pharmaceuticals
Pharmaceutical is a generic name for thousands of different products and compounds that are used for prevention and treatment of diseases. Because of their spread use and variety, it is hard to detect all of the different pharmaceutical compounds and understand their fate in WWTPs. It is important to study drugs that due to their wide use are present in the environment. Some of these may have harmful effects even in small quantities. Antibiotics in the environment are especially a concern because even when they are present in only small quantities, they can induce antibiotic resistance in bacteria. (Jones, et al., 2005) Pharmaceuticals are a problematic issue and differ from other PHCs in wastewater treatment. As these cannot be forbidden due to ethical reasons and the use of them is hard to restrict, other methods to reduce their presence in the environment must be studied. Pharmaceuticals are also mostly synthetic and made in a way to have a large biological effect and still be quite persistent. They can also be constructed in a way that they are not degraded by the micro bacteria in the intestines. Pharmaceuticals have in many ways the same attributes as pesticides but the big difference is that they are usually released into the environment after they have been broken down in the body. (Swedish Environmental Protection Agency, 2008) Pharmaceutical products are used all over the world to treat humans and animals. There is little research about how much of these products, their residues or degradation products come into the sewage treatment plants and through there into water supplies and nature. Some pharmaceutical residues are believed to get into nature through pharmaceutical factories and improper disposal of pharmaceutical products. These are however considered to be small in comparison to the pharmaceutical residues that are released with the excretion from the users of the remedies. (Jones, et al., 2005) As pharmaceuticals are made to treat humans and animals, they are constructed in a way that the body can take them up easily. They are therefore often biologically active, hydrophilic and persistent so that they do not degrade earlier than wanted. (Urase & Not all pharmaceutical compounds are biodegradable, but studies have been made and e.g. paracetamol and ibuprofen, both very common compounds in painkillers and anti- inflammatory medicine, were found to be largely biodegradable. Pharmaceutical compounds are also observed to sorb to sludge and if the sludge is not treated, these go into sludge utilization or disposal and through there into groundwater and environment. It has been observed that sludge treatment, for example thermal treatments, have reduced the amount of pharmaceutical compounds in sludge. It is also possible to with more advanced wastewater treatments reduce the concentrations of these compounds. The reduction of pharmaceutical compounds is possible in WWTPs today, but the total removal may be too costly to optimize. The effort to reduce nutrients in wastewaters has also led to the reduction of pharmaceuticals. (Jones, et al., 2005) Under normal conditions, there has been no evidence of pharmaceuticals disturbing the wastewater treatment process, but it can't be excluded that these may in some way have a negative effect. (Swedish Environmental Protection Agency, 2008) In a study made by Kraigher et al. (2008) the influence of pharmaceuticals residues on microbial communities in wastewater treatment was studied. They found that acidic drugs, such as ibuprofen and diclofenac at levels of 50µg/l reduced diversity and caused shifts in the structure of microbial communities. They found that these drugs can possibly have an influence on especially the nitrogen removing bacteria. (Kraigher, et al., 2008) The consumption of some widely used and studied pharmaceuticals in Finland 2010 can be found inThe consumption was calculated with Equation 10. (Vieno, 2007) Table 4 Pharmaceutical consumption in Finland 2010 (Finnish Medicines Agency, 2011)
4.3.1 Ibuprofen
Ibuprofen is a non-steroidal acidic anti-inflammatory drug that is largely used throughout the world. (Lischman, et al., 2006) Acidic drugs are ionic in neutral pH, which makes them an interesting compound to study. They do not sorb to sludge although according to their kow values they should, but this does not take into account the effect of pH. (Thomas & Foster, 2005) Ibuprofen is an over-the-counter drug that is used to treat many different illnesses and symptoms, including fever and headaches. The therapeutic dose of the drug is large (up to 1200mg/d) and 70-80% of this is excreted unchanged after use. This means that a large proportion of ibuprofen is getting to WWTPs. (Smook, et al., 2008) The compound has been detected in Finnish surface water in concentrations up to 65ng/l and in WWTP influents and effluents 20µg/l and 4µg/l respectively. This is more than in most other European countries. (Ternes, 2004) It has been shown that ibuprofen does not volatilize or sorb to the sludge. The main removal method of ibuprofen is therefore biodegradation. Most of the drug biodegrades in the aeration tank during secondary treatment in a conventional WWTP with activated sludge. The total removal of ibuprofen in WWTPs can be up to 99%. (Smook, et al., Clara et al. (2005) studied the occurrence and removal of pharmaceuticals in three different wastewater treatment plants. From one of the three plants, samples were taken at three different occasions and temperatures. They detected that the biodegradation of ibuprofen was not affected by the change in temperature between 7-22°C. In this plant, the SRT was well over 10 days and the food per mass ratio (F/M) was low, 0.02gCOD/gTSS. The removal of ibuprofen was over 90%. However at another plant, that had an SRT of only 2 days and a high F/M ratio of 1.7gCOD/gTSS, no ibuprofen removal took place. The plant was design for only organics removal. The influent concentration of ibuprofen in both WWTPs was around 2400ng/l. (Clara, et al., 2005) The drug oxidizes to hydroxyl and carboxyl metabolites in WWTPs and this often contributes to the high removal rates. (Paxéus, 2004) Although the drug has a high removal rate in activated sludge WWTPs, it is still found in environmental waters due to the high influent concentration and nowadays low detection limits. (Malmi & Mannio, 2008) The drug has also been found to bioaccumulate in pH values below 5.5. (Det Norske Veritas, 2006) Roh et al. (2009) discovered that ibuprofen was not degraded by the ammonia-oxidizing bacteria Nitrosomonas europaea but it did degrade in nitrifying activated sludge. Some studies have detected ibuprofen-degrading bacteria but it is not known which strains are responsible for the biodegradation of ibuprofen in WWTPs. (Roh, et al., 2009) Table 5 Properties of ibuprofen
a-Methyl-4-[isobutyl] phenylacetic acid Chemical structureMolecular weight Anti-infammatory drug Suarez et al. (2008) Smook et al. (2008) kbiol values for ibuprofen
The biodegradation rate constants found for ibuprofen in literature are presented in The three studies made by Joss et al. (2006), Ternes (2004) and Smook et al. (2008) studied the biodegradation of ibuprofen in activated sludge. The results were analyzed as pseudo first order degradation by which the biodegradation rate constant The study made by Joss et al. (2006) studied the biodegradation of ibuprofen in batch experiments. Wastewater from WWTPs was spiked to levels of 3µg/l ibuprofen and the biodegradation of the compound was studied in a batch with MLSS concentration of 3.2g/l. The experiments were made in a laboratory where the temperature was 17 ± 1°C. The sludge used from a WWTP had a sludge age of 11 ± 1 days and COD concentration of the influent wastewater was 275mg/l. They obtained the kbiol values of 21-35 l/gSS/d. (Joss, et al., 2006) Ternes (2004) studied many different WWTPs in Europe and detected that when the sludge age was over 5 days, the kbiol values were 23 ± 10 l/gSS/d. The third experiment by Smook et al. (2008) studied the biodegradation in the aeration tank in a WWTP that uses conventional activated sludge process for nutrient removal. The HRT in the aeration tank was 7 hours and the MLSS concentration was on average 2.33g/l. (Smook, et al., 2008) 4.3.2 Diclofenac
Diclofenac is, as ibuprofen, a non-steroidal acidic anti-inflammatory drug. It has been noticed that the drug can cause serious effects to animals. A species of birds were almost extinct in India because of a spill of the compound and it has been shown to cause liver faults in rainbow trout. (Swedish Environmental Protection Agency, 2008) In Finnish surface waters the drug is found at lower concentrations than in the rest of Europe. (Ternes, 2004) Diclofenac has shown poor biodegradation and sorption to sludge. Biodegradation is still possible under some conditions. A low removal rate of 15-40% has been shown in WWTPs. (Zang, et al., 2008; Ternes, 2004) The poperties of diclofenac are summarized in Table 6. Table 6 Properties of diclofenac
2-[(2,6-Dichlorophenyl)amino] benzeneatic Chemical structureMolecular weight Anti-inflammatory drug Suarez et al. (2008) 4.3.3 Paracetamol
Paracetamol, even known as acetaminophen, is an analgesic drug. It is one of the most commonly used non-steroidal analgesic drugs. Contrary to ibuprofen and diclofenac, it has a low anti-inflammatory effect. It is metabolized in the liver and can in high doses be toxic and cause liver failure. (Rang, et al., 1995) In a study of the removal of pharmaceuticals at a southern English WWTP, it was found that paracetamol was removed on an average of 92% over a four day sampling period. The WWTP used activated sludge treatment as their secondary biological treatment process. They had also nitrification and denitrification zones. The mean temperature at the time of sampling was 20.6°C and the sludge age 3 days. The concentration found in influent wastewater was 2-3µg/l. (Jones, et al., 2005) Paracetamol biodegrades fast and has as high kbiol of 58-80 in activated sludge. (Joss, et al., 2006) The properties of paracetamol are summarized in Table 7. In a study made at a WWTP in Spain they found paracetamol at levels of 7.1-11.4µg/l in the influent. The WWTP received both municipal and industrial wastewaters, which included pharmaceutical industry. The WWTP used activated sludge as secondary biological treatment, with both anoxic and aerobic zones. The SRT during the time of sampling was 10 days and the HRT 11.5 hours. They detected that paracetamol was removed to up to 99.9 ± 0.1% from the aqueous phase in the WWTP. The study concluded that due to the fast biodegradation, paracetamol does not sorb to sludge in significant amounts. (Radjenovic, et al., 2009) Table 7 Properties of paracetamol
Chemical structureMolecular weight Jones et al. 2002 Joss et al. 2006 Joss et al. 2006 4.3.4 Carbamazepine
Carbamazepine is used to treat seizures in epilepsy and has been found in many studies in WWTP effluents and natural waters. Because of its low removal rate in WWTPs, the compound has been proposed to serve as an anthropogenic marker. Less than 10% of Carbamazepine is removed in WWTPs and it is often classified as not removable. In some cases the removal rate has been 30%, but mostly the removal is only 0-10%. Longer SRT has not been shown to influence the removal of carbamazepine. It neither biodegrades nor sorbs in any large extent to the sludge in WWTPs and stays therefore in the aquatic phase and is released with the effluent into nature. (Zang, et al., 2008) The properties of carbamazepine are summarized in Table 8. Table 8 Properties of carbamazepine
Chemical structureMolecular weight Anti-epileptic agent Suarez et al. (2008) Suarez et al . (2008) 4.3.5 Antibiotics
Antibiotics are drugs that are used to treat and prevent microbial infections both in humans and animals. A large amount of antibiotics that are used, are excreted unchanged and transferred to WWTPs. Antibiotics are also used in breeding of livestock animals, in feed additives and in the poultry industry. The biggest concern with letting antibiotics into the environment, and the effects on human health, is the risk of antibiotic resistant bacteria developing. (Lindberg, et al., 2005; Kim & Aga, 2007) A high number of antibiotic resistant bacteria can be found in wastewaters. Here different bacteria from many different individuals have an opportunity to react with each other and this has potential genetic consequences. Studies have shown that antibiotic resistant bacteria favor the conditions at a WWTP and this may lead to the transfer of the antibiotic resistant gene to other bacteria. The conditions at WWTPs have been shown to lead to a greater likelihood of transfer of the gene. (Kim & Aga, 2007; Fatta- Kassinos, et al., 2011) Fluoroquinolones is a group of antibiotics that are largely used in Europe and especially Scandinavia. They have been observed to mostly sorb to sludge and have a very low to none biodegradability in conventional WWTPs. (Lindberg, et al., 2005; Vieno, et al., 2007) In a research made by Vieno et al. (2006) the fluoroquinolones ciprofloxacin, norfloxacin and ofloxacin were found in both effluents and influents at WWTPs, surface waters and in ground- and tap water in Finland. They also detected that over 80% of these fluoroquinolones were removed in WWTPs in Finland. They did not research how the antibiotics were removed from the wastewater. (Vieno, et al., 2007) Similar removal rates have also been observed by Lindberg et al. (2005) in Swedish WWTPs. The properties of the fluoroquinolones ciprofloxacin, norfloxacin and ofloxacin are summarized in Table 9. Table 9 Properties of ciprofloxacin, norfloxacin and ofloxacin
Chemical structureMolecular weight Vieno et al. (2006) Vieno et al. (2006) Chemical structureMolecular weight Vieno et al. (2006) Vieno et al. (2006) de]-1, 4-benzoxazine-6-carboxylic acid Chemical structureMolecular weight Vieno et al . (2006) 4.3.6 β-Blockers
β-blockers are drugs used to treat high blood pressure and in treatment after heart attacks to prevent new attacks. The removal of these drugs in WWTP have become increasingly interesting, as they have been found in natural waters and ecotoxicological tests have shown them to be toxic to algae and aquatic animals. β-blockers are positively charged at pH values of around 7 and weak bases. (Maurer, et al., 2007) Metoprolol
Metoprolol is the most used β-blocker in Finland and it has been found in natural waters, lakes and WWTPs. (Vieno, et al., 2007) In experiments made by Maurer et al. (2007) it was shown that metoprolol does not sorb to sludge in significant amounts and that the main way of removal in WWTP is by biodegradation. The biodegradation rate constant, kbiol, of metoprolol was calculated to be 0.58l/gSS/d. The compound's biodegradation is between 25-70% of the influent concentrations. (Maurer, et al., 2007) Wick et al. (2009) detected that the biodegradation of metoprolol takes place in the nitrification tank in a conventional WWTP. The properties of metoprolol are summarized in Table 10. Table 10 Properties of metoprolol
quinolinecarboxylic acid Chemical structureMolecular weight Vieno et al. (2006) Maurer et al. (2007) 4.3.7 X-ray contrast media
X-ray contrast media are used in radiological examinations. They are a major part of the pharmaceuticals that leave hospitals with wastewater to WWTPs. As they are only used in human medicine, WWTPs are most likely the only source of X-ray contrast media contamination in the environment. (Ternes & Hirsch, 2000) Iopromide
Iopromide is an X-ray contrast that is used when examining blood vessels and organs. The compound is very stable and almost all of it is excreted out of the human body unchanged within a day. (Batt, et al., 2006) Hospital wastewater effluent is the major source for iopromide to WWTPs as the compound is used only at hospitals for diagnostic purposes. (Fatta-Kassinos, et al., 2011) In Germany in a study made at a WWTP close to Frankfurt am Main, iopromide was found in wastewater influent and effluent at concentrations of 7.5±1.5µg/l and 8.1±1.6µg/l respectively. No removal could be shown of the compound in the wastewater treatment process. (Ternes & Hirsch, 2000) Iopromide is believed to go through the WWTP largely unchanged. (Batt, et al., 2006) It has shown some capability to biodegrade but the results are contradictory and need further research. (Ternes, 2004) The properties of iopromide are illustrated in Table 11. Table 11 Properties of iopromide
Chemical structureMolecular weight Joss et al. (2006) 5. Emerging industrial potentially harmful compounds
5.1 Nonylphenol (NP)
Nonylphenol (NP) is a xenobiotic compound found to have many harmful effects. Most NP has its origin as a degradation product from Nonylphenol Ethoxylates (NPE) that are used as industrial surfactants, detergents, cleaners and degreasing agents. NP found in the environment is a strong sign of human activity, such as wastewater treatment, nearby. NP is a hydrophobic compound that adsorbs to sludge solids and does hardly degrade. It is possible for the compound to be degraded by microbial activity but the biodegradation is strongly dependent on oxygen and bioavailability of NP. (Soares, et al., 2008) NP has been found to be toxic and bioaccumulate in fish. It has also been found to disturb the hormonal system in many animals and organisms and is classified as an EDC. (Swedish Environmental Protection Agency, 2004) The use of NPE is restricted in the EU and it is listed as a priority substance. NPEs have been changed to other, not as harmful, surfactants. Regulatory steps for reducing the amount of NP in the environment have also taken place in some parts of the world, such as the USA, but in many countries the production and use of NPE is still taking place. (Soares, et al., 2008) The properties of NP are summarized in Table 12. In the E-PRTR study, a study of harmful compounds in Finnish wastewaters, the concentration of NP was measured at 26 different WWTPs. The average concentrations of NP/NPE in influent wastewater was 181.91µg/l and in effluents <1.12µg/l. (VVY, According to the Simple Treat model for WWTPs, 24% of NP biodegrade in wastewater treatment. (Malmi & Mannio, 2008) In other studies the main removal of NP has been detected to be through sorption to sludge. (Soares, et al., 2008) Table 12 Properties of nonylphenol
Chemical structureMolecular weight Metobolite of alkyl phenols Soares et al. (2008) 5.2 Organotin (OT) compounds
Organotin (OT) compounds are a group of over 800 different compounds, almost all of them man-made. (VVY, 2008) OT compounds are used in many applications including biocides, agrochemicals, antifouling paints, UV and thermal stabilizers and in the production of foams and silicone. There are many different OT compounds including Tributyltin (TBT), Dibutyltin (DBT) and Monobutyltin (MBT). TBT is toxic and the levels of TBT found in marine and freshwater environments are a growing concern. (Stasinakis, et al., 2005) In the EU, the use of OT antifouling paints on vessels is forbidden and after 2008 ships entering EU ports were forbidden to use these paints. Also biocides that use TBT are no longer on the market in the EU. The use of other OT compounds, in consumer products and as wood preservatives, is a rising concern in the EU. (RPA, 2005) OT compounds slowly biodegrade in sediment, especially in cold conditions. Both biological and chemical degradation decomposes OT compounds. The concentrations of OT compounds and especially TBT in 10 WWTPs were studied in the E-PRTR study in Finland. The average of OT compound concentration in influent water was 0.084µg/l and in effluent water 0.009µg/l. TBT was found in influent wastewater on an average of 0.005µg/l and in effluent < 0,003µg/l. (VVY, 2008) Stasinakis et al. (2005) studied the biodegradation of OT compounds in a SBR with both acclimatized and non-acclimatized activated sludge. They found that TBT first accumulated to the sludge but started to biodegrade during the experiment. This same happened to DBT and MBT but not in the same extent. When using non-acclimatized activated sludge the biodegradation was much lower. They also tested the biodegradation in the presence and without supplemental substrate. They found that OT compounds can be used as a single carbon source in the activated sludge process. The presence of supplemental substrate only enhanced the biodegradation of TBT, but did not affect the biodegradation of the other tested OT compounds. When using acclimatized activated sludge TBT, DBT and MBT biodegraded 99.7%, 90.4% and 49.7% respectively. (Stasinakis, et al., 2005) 5.3 Perfluorinated compounds
Perfluorinated Alkyl Compounds (PFAS) are a large chemical group of emerging pollutants with different toxicity and behaviors. They are found in the environment all over the world and are mostly very stable compounds. PFAS chemical structure is made of a hydrophilic head group with a completely fluorinated alkyl chain. Because of the fluorinated structure they are not biodegraded in the WWTPs. PFAS are used in cleaning supplies, firefighting foams and in the textile industry. (Finnish Ministry of the Environment, 2005; Sáez , et al., 2008) The most common PFAS in WWTPs are Perfluorosulfonate (PFOS) and Perfluorooctanoic Acid (PFOA). PFAS have been found in Finnish seawater and rain up to 37ng/l. Concentrations of 2.5ng/g solids has been found in WWTP sludge. (Korkki, 2006) In a study that measured concentrations of PFAS in six different WWTPs in New York State, concentrations of up to 68ng/l of PFOS and 700ng/l PFOA were found in effluent waters. (Sinclair & Kannan, 2006) PFOS and PFOA have been found to accumulate in the liver and they are carcinogenic. They have a lot in common with POPs. They have been found in fish, seals and even in humans. Especially PFOS is persistent, toxic and bioaccumulates in the environment. (Korkki, 2006) The use of PFOS is forbidden (with some exceptions) in Finland since 2008 and its use in firefighting foams was stopped in 2011. (SYKE, 2008) Firefighting foams were the biggest source of PFOS in Finland in 2004. (Korkki, 2006) PFOS does not biodegrade and most of it will leave a WWTP in the effluent. According to the Simple Treat model, about 28% of PFOS will sorb to sludge. (Malmi & Mannio, 2008; Finnish Ministry of the Environment, 2005; Sáez,et al., 2008) The only way to remove PFOS is by burning in high heat. The exact temperature for this to take place has however not been determined. (Korkki, 2006) 5.4 Bisphenol A (BPA)
Bisphenol A (BPA) is a compound largely used in the manufacturing of resins and plastics. It is mostly used to manufacture polycarbonate. Polycarbonate is a rigid plastic that is used in different types of food containers. BPA is also used as a coating agent in other food and beverage cans. This is an important source of BPA to humans, as residues of the compound can migrate from the containers. In January 2011 the European Food Safety Authority (EFSA) banned the production and import of baby bottles that contain BPA. (European Food Safety Authority, 2011) BPA is an EDC and has been found to be toxic to aquatic animals in concentrations of 1-10µg/l. (Roh, et al., 2009) BPA has been found to biodegrade in lab-scale experiments with aerobic activated sludge up to 72-99%. (Liu, et al., 2009) In the study made by Roh et al. (2009) it was detected that BPA is biodegraded by the ammonia- oxidizing bacteria N. europeae. Also other bacteria found in wastewater treatment plants have been found to biodegrade BPA. (Roh, et al., 2009) The properties of BPA are summarized in Table 13. Table 13 Properties of BPA
Bisphenol A
Chemical structureMolecular weight Residual and intermidiate in production of flame retardants etc.
Urase et al . (2005) 5.5 Polycyclic Aromatic Hydrocarbons (PAHs)
Polycyclic Aromatic Hydrocarbons (PAHs) are formed during incomplete combustion of organic material. PAHs form during all sorts of combustion from forest fires to diesel engines. PAHs can also be found in crude oil and in wood preservatives. They form a group of many different compounds and most of them are carcinogenic and can cause genetic damage. They are also mostly persistent and in some cases bioaccumulating. PAHs are dispersed everywhere in the world and the environment. (Swedish Environmental Protection Agency, 2004) PAHs include toluene, benzene, xylene, naphthalene etc. (Bitton, 2005) PAHs are easily evaporated and dissolve poorly to water. In WWTPs they biodegrade slowly under aerobic conditions and partly sorb to sludge. In the E-PRTR study about harmful compounds in Finnish WWTPs, PAHs were found in influent and effluent wastewater on an average of <0.087µg/l and <0.026µg/l respectively. The reduction of PAHs in the plants varied from 50-98% with a median of 90%. (VVY, 2008) 5.6 Phthalates
Phthalates are used as plasticizers mainly in PVC production but also in production of paints, PPCPs, glues and lubricants. (Roslev, et al., 2007) Due to their large use, phthalates can be found in the environment all over the world. They have been found to be toxic to algae and in large quantities to be endocrine disruptive. It has been noticed however, that they metabolize rapidly in vertebrates, so they should not be harmful. (Swedish Environmental Protection Agency, 2004) As the phthalates are most often not bound to a product, the compounds can escape to the environment in any phase of a products lifecycle. They have also been shown to bioaccumulate in the environment. (Roslev, et al., 2007) Most discussed and tested phthalates are Dibutyl Phthalate (DBP), Butylbenzyl Phthalate (BBP) and (di-8a-ethylhexyl) Phthalate (DEHP). (Roslev, et al., 2007; Swedish Environmental Protection Agency, 2004; Malmi & Mannio, 2008; Finnish Ministry of the Environment, 2005) According to the Simple Treat-model for WWTPs, DEHP, DBP and BBP biodegrade 15%, 58% and 57% respectively. (Malmi & Mannio, 2008; Finnish Ministry of the Environment, 2005) In experiments made by Roslev, et al. (2007) they observed a total degradation (biodegradation in activated sludge process and degradation in sludge digestion) of 81%, 91% and 90% for DEHP, DBP and BBP. (Roslev, et al., 2007) Marttinen et al. (2003) studied the removal of DEHP at Suomenoja WWTP and detected a biodegradation of 29% in the activated sludge process and a 32% biodegradation in sludge digestion. The temperature at the treatment plant during the sampling period was 18.5°C, the mechanical HRT was 4 hours, the biological HRT 20 hours and the aerobic nitrification sludge age was 7 days while the total sludge age was 14 days. (Marttinen, et al., 2003) The most commonly used phthalates are biodegradable but also sorb to sludge under some WWTP conditions. They are also found in effluents of WWTPs. (Finnish Ministry of the Environment, 2005) Phthalates that have longer chains are more likely to sorb to sludge than biodegrade. (Swedish Environmental Protection Agency, 2008) 5.7 Brominated flame retardants
Brominated flame retardants are used in electronic equipment, plastics, rubbers, textiles and fibers. Their use has increased in recent decades due to computerization and stricter fire and safety standards. These compounds have been found in most places in the environment. Some of them have been found to bioaccumulate, be carcinogenic and neurotoxic. However more research is needed to understand the effects of these compounds. As there are no other as effective options to use as flame retardants, the amount of these are expected to increase in the environment. (Swedish Environmental Protection Agency, 2004; Koskinen, et al., 2005) The first brominated flame retardants to be used were Polybrominated Biphenyls (PBBs). The use of these has decreased as they were found to be very toxic when an accident with the chemical killed livestock. After that the use of Polybrominated Diphenyl Ethers (PBDEs) started and they were also found to bioaccumulate and have harmful effects. (Swedish Environmental Protection Agency, 2004) The PBDEs are mostly banned by the Stockholm Convention. Today the most used brominated flame retardants are Tetrabromobisphenol A (TBBP-A) and HBCD. (Finnish Ministry of the Environment, 2010) According to Simple Treat-model for WWTPs, TBBP-A does not biodegrade but mostly sorbs to sludge (80-90%). (Malmi & Mannio, 2008) 5.8 Chlorinated paraffins
Chlorinated paraffins are a group of compounds that are used for different industrial applications throughout the world. They are used as components in lubricants, coolants in metal cutting, plasticizers, flame retardants in plastics, rubber, paints, coatings, adhesives and sealants. (United States Environmental Protection Agency, 2009) Chlorinated paraffins are divided into three groups after their carbon chain length; Short-Chain Chlorinated Paraffins (SCCPs), Medium-Chain Chlorinated Paraffins (MCCPs) and Long-Chain Chlorinated Paraffins (LCCPs). Of these, SCCPs are considered to be the most harmful and in the EU regulatory measures to lessen their production and use has been made. (United States Environmental Protection Agency, 2009) SCCPs are found in biota, water and many other places in the environment. They are present even in remote places like the arctic. (Stockholm Convention, 2009) SCCPs have been found to behave like POPs. They bioaccumulate and sensitive aquatic animals can be effected even at relatively low concentrations (<5µg/l). There is no conclusive evidence that SCCPs pose any risks to humans, although some research suggests that they may be carcinogenic. (Stockholm Convention, 2009) The fate of SCCPs and other chlorinated paraffins in WWTPs have been scarcely studied. Most of SCCPs that come in the influent wastewater seem to end up in the sludge. A fraction of the influent SCCPs ends up in the effluent wastewater. WWTPs are however a big source of SCCPs that ends up in the environment. (Zeng, et al., 2011) SCCPs have been found in influent and effluent wastewater in Japan 220-360ng/l and 16-35ng/l respectively. In Canada concentrations of 59-448ng/l have been found in effluent wastewater from WWTPs. The higher concentrations are found in industrialized areas. (Stockholm Convention, 2009) 6. New research areas
6.1 Sucralose
The artificial sweetener sucralose has been used since 1999, when the United States Federal Drug Administration permitted it for use. Today it is used in more than 80 countries and in thousands of different products. Sucralose has been shown to be excreted almost unchanged from the human body. Although it was proven that the sweetener is safe to use, it has now been shown to affect the gut fauna in rats. This can mean that it has a disturbing effect on microbes. (Torres, et al., 2011) The only way of removing sucralose in a WWTP is believed to be via biodegradation. Due to its hydrophilicity it does not sorb to sludge. Tests have also shown that sucralose does not biodegrade in large amounts in WWTPs and it has already been found in significant amounts in surface waters in countries it is used. (Torres, et al., 2011) The compound has been proposed to be used as an anthropogenic marker due to its sustainability and because it is only produced synthetically. (Soh, et al., 2011) Sucralose has been detected in Swedish sewage treatment plant influents 3.5-7.9µg/l and in Finnish rivers in concentrations up to 0.1µg/l. (Loos, et al., 2009; Brorström-Lundén, et al., 2008) The properties of sucralose are collected in Table 14. In a Swedish research of 25 WWTPs where sludge and influent and effluent wastewater was sampled, it was found that sucralose was removed under 10% in the wastewater treatment process. The compound was also found in some samples in small amounts in sludge. It was however concluded that sucralose does not sorb, in significant amounts, to sludge. (Brorström-Lundén, et al., 2008) Table 14 Properties of sucralose
Chemical structureMolecular weight Artificial sweetener Brorström et al . 6.2 Nanoparticles
Nanoparticles are compounds of the size of 1-100nm. (Finnish Ministry of Environment, 2010) Nanoparticles are a growing research area for both industry and scientists. They have a large potential for different applications but the toxicological effects have not been studied. It is estimated that the use of engineered nanoparticles will increase in the future. (Kummerer, et al., 2011) Nanoparticles, due to their small size, can exhibit properties that the material does not have in bigger size. Also manipulation of a material at nano level makes different scenarios and applications possible. Nanotechnology can and is used in medication, engineering etc. to get more precise properties. It has however not been studied what these engineered properties can have for effects on humans or nature when they are let into the environment. (Albrecht, et al., 2006) The most used engineered nanoparticles are nanosilver and TiO2. Nanosilver has antifungal, antimicrobial and antiviral properties. (Mueller & Nowack, 2008) As antibiotics resistance is a growing risk due to the extensive use of antibiotics and antimicrobial compounds, researchers try to find other alternatives to these. As nanosilver has shown antimicrobial properties its use is growing. (Khan, et al., 2011) TiO2 is used in paints, coatings and is very common in sunscreens. As TiO2 exhibits self-cleaning and antifouling properties, these make it a desired compound. (Mueller & WWTPs have an important role in preventing large amounts of nanoparticles from being released into nature. It has been proven that large amounts of nanosilver are being released into WWTPs when washing socks that contain nanosilver. However research on the fate of nanoparticles in WWTPs is lacking. Preliminary research implicates that nanosilver is most likely to sorb to sludge. (Kim, et al., 2010) 6.3 Advanced treatments
Conventional WWTPs were not designed to remove the emerging contaminants that lately have raised concerns. This is why other, more advanced treatments, are being studied to determine if these could prevent PHCs from entering the environment. (Bolong, et al., 2009) Some possible advanced treatments are listed below.  Membrane Bioreactors (MBR)  Activated carbon  Oxidation with ozone  Ultra-Violet (UV) photolysis  Ion-exchange All the above-mentioned treatments have been tested on different types of emerging pollutants and can be more effective than traditional methods. The results are however largely dependent on the compound and its chemical structure. Some, like ion-exchange and UV photolysis have shown to be effective but insufficient. (Bolong, et al., 2009) A pilot scale ozonation plant was added to an Austrian WWTP when it was found that it did not remove significant amounts of micropollutants. The plant had upgraded to include nitrogen removal when it was found that this increased the removal of micropollutants, but not significantly enough. The use of ozonation enhanced the removal of diclofenac and carbamazepine. (Shaar, et al., 2010) According to Jones et al. (2007) the implementing of advanced treatments for the removal of PHCs, like pharmaceuticals and EDCs, may not be beneficial. Although the removal rate may be very good with advanced treatments, the increase in CO2 emissions and high costs may lead to more negative effects than the PHCs would have caused. As traditional treatment methods may not be as effective, they can still remove large concentrations of PHCs, if designed correctly. (Jones, et al., 2007) 6.4 The future of pharmaceuticals
One way of eliminating the possible negative effects that pharmaceuticals have on the environment, is to develop environmentally safer and more sustainable pharmaceuticals i.e. "green" pharmaceuticals. In Sweden a development toward more sustainable use of pharmaceuticals has started with a new way of categorization. Regulatory agencies together with the chemical industry have developed a labeling system that describes the Persistence, Bioaccumulation and Toxicity (PBT) of a pharmaceutical. The scale goes from 0-9 and the higher the score, the more dangerous the compound is for the environment. This way doctors and consumers can decide to use a drug that has less environmentally hazardous effects than another but with the same physiological effects. (Fatta-Kassinos, et al., 2011) A study made by Larsson et al. (2007) sampled the effluents of a WWTP in Patancheru in India that received the wastewater from 90 bulk drug manufacturers. In this study high levels of pharmaceuticals, especially of the antibiotics (fluoroquinolones), were found. Ciprofloxacin was found at concentrations of 28000-31000µg/l. This concentration is higher than the largest therapeutic levels in human plasma. Before it was thought that the municipal WWTPs and improper disposal of drugs were the largest sources of pharmaceuticals in the environment. But very little research has been made of the effluents from drug manufacturers. The drugs manufactured in this area of India are distributed globally and used in the products of other pharmaceutical companies. (Larsson, et al., 2007) 7. Sequencing batch reactor
7.1 History
The Sequencing Batch Reactor (SBR), a semi-continuous wastewater treatment process, was developed in the 1920s in the United States and became more popular in the 1990s. It is preferred in places where there is not much room for treatment facilities or square footage is expensive. SBRs are also effective when the flow rates vary largely with time. Especially milk farms and other types of farms that need their own wastewater treatment facilities prefer SBR as they do not take up much space, it is easy to decide when to have it running and control the flows. (Wilderer, et al., 2001) Other places where SBR technology is and could be used is in treating landfill leachate and wastewaters from breweries, tanneries, wineries etc. (Mace & Mata-Alvarez, 2002) 7.2 The treatment process
The treatment processes in SBRs are all taking place in one single reactor and the process bases on a fill-and-draw principle. This is why SBRs are space saving. SBRs are based on the activated sludge process. The wastewater treatment in SBRs is organized in timed and controlled sequences. Equalization, biological treatment and clarification all happen timed one after other. This differs from a continuous activated sludge process where the different treatment processes takes place in separate tanks and the wastewater continuously flows through the system. (United States Environmental Protection Agency, 1999) The SBR treatment process consists of five stages; fill, react, settle, draw and idle. The treatment steps can be seen inBefore the treatment in the batch reactor, the influent wastewater is usually led through screens and grit removal to remove the biggest constituents as in a conventional municipal wastewater treatment plant. (United States Environmental Protection Agency, 1999) Figure 3 The five steps in a SBR.
During the fill stage the reactor is filled with influent wastewater. The batch is already half-full with sludge and water from the previous cycles. The influent wastewater is a source of substrate for the activated sludge and sets the biological reaction going. The fill stage of the process can be created in different ways depending on if aeration and/or mixing are used. Static fill can also be chosen, which means that no aeration or mixing is taking place. The decision if aeration is used in the fill stage, depends on if anaerobic or aerobic conditions are preferred in the beginning of the process. (New England Interstate Water Pollution Control Commission, 2005) During the react stage, aeration makes removal of organics and nitrification possible and anoxic conditions without aeration (with mixing) enable denitrification and thus leading to total nitrogen removal. Alternating anaerobic and aerobic conditions also lead to biological phosphorus removal by polyphosphate organisms. During the third step, both aeration and mixing is turned off to let the sludge settle and clear the water. There are no other currents interfering with this process as there is no effluent or influent flow to the SBR. (United States Environmental Protection Agency, 1999) In the draw stage effluent is taken away from the tank. Different types of decanters can be used for this purpose. The amount of effluent water to be removed varies depending on the design and scale of the SBR. The effluent water in the decant stage should be the same volume as the influent in the fill stage. One recommendation is that no more than a third of the operating volume should be emptied in the draw stage in a SBR process. The final, idle stage is between the draw and fill stages. The length of this stage depends on the chosen operational strategies. (New England Interstate Water Pollution Control Commission, 2005) Sludge wasting is also an important step in the process. This can occur at any stage of the cycle but it has been recommended that the wasting should take place during the reaction stage. The amount of the sludge wasted, depends on the selected SRT. Because the aeration and settling stages both occur in the same tank, there is no need for Returned Activated Sludge (RAS) to be fed to the system. (Metcalf & Eddy, 2003) 7.3 The design
When building an SBR plant for industrial- or municipal wastewater, pilot studies are recommended. By evaluating the treatability of the influent wastewater and optimizing the operation beforehand, possible cost savings can be made during the actual building of the plant. (Wilderer, et al., 2001) In an SBR process it can be necessary to add alkalinity as nitrification uses up the naturally existing alkalinity in the water. There are several options of chemicals to choose from. Sodium bicarbonate, sodium carbonate and calcium hydroxide are all examples of chemicals that can be used to add alkalinity to the SBR process. The choice of chemical depends on the process and the preferences of the operation personnel. (New England Interstate Water Pollution Control Commission, 2005) 7.4 Advantages and disadvantages
SBRs can be cost effective as all the process stages are in one single reactor. This means that no big clarifiers or other tanks need to be built. SBRs are also very flexible and easier to control than regular activated sludge processes. A disadvantage is however that much maintenance, good timing and control systems and knowledge of the process is needed. The potential of plugging in devices and pipes is also a risk in SBRs. (United States Environmental Protection Agency, 1999) 8. Description of methods used in analyses of potentially harmful
compounds
8.1 Analyzing PHCs in wastewater
To analyze small concentrations of pharmaceuticals and other PHCs in water pose a special challenge due to the low concentrations present. Recently different methods have been developed to make this possible. Solid Phase Extraction (SPE) with Liquid Chromatography (LC) and Mass Spectrometry (MS) has shown to be an effective method for sample preparation and analysis of pharmaceuticals in water matrixes. (Batt, et al., 2008; Farré, et al., 2007) 8.1.1 Solid Phase Extraction (SPE)
Many of the PHCs are dissolved into lipids. To be able to analyze these, methods to extract the compounds need to be made. SPE is a method where solids and liquids are partitioned. SPE can be done manually, but automatic SPE by analyzing equipment has been developed. (Beruetta, et al., 1995) The reasons for needing SPE are many. SPE can be used when wanting to remove interfering compounds from samples, to get higher concentrations of e.g. organic pollutants (pre-concentration), to fraction different groups of compounds in a sample, to store analytes that are unstable in liquids and to derivatize reactions between reactive groups of the analytes. (Beruetta, et al., 1995) The SPE process includes five steps. First, the sorbent is activated by letting it pass through a solvent the function of which is to condition the solids surface. Then the solvent is removed by liquid with similar composition as the sample matrix. The third step is the application of sample, or the sorption or retention step. Here the sorbent will retain the analytes. After this, the interfering compounds that were retained are removed with a sorbent that does not remove the analytes. The last step is the elution step where the analytes are eluted from the adsorbent using a solvent. (Beruetta, et al., 1995) 8.1.2 Liquid Chromatography (LC)
LC is used to fraction samples with different properties. The principle of this method is that different compounds travel through liquids at different speeds and this way, different compounds can be separated from each other. The most commonly used separation technique when analyzing pharmaceuticals in water samples is High Performance Liquid Chromatography (HPLC). HPLC uses pressure to accelerate the particles. (Batt, et al., 2008) Ultra Performance Liquid Chromatography (UPLC) is a new technique and improved version used instead of HPLC. In UPLC higher pressure is used together with small particle sized columns. The advantage of UPLC is that it can be used in batch analysis. It has also shown to have better sensitivity, resolution, reduces analysis time and the need of solvents. (Batt, et al., 2008) 8.1.3 Mass Spectrometry (M/S)
M/S is used to detect compounds, such as pharmaceuticals. Tandem mass spectrometry MS/MS is the most frequently used detection system. Mass spectrometry is used after sample preparation such as SPE and HPLC and can assess the mass of a compound detected in LC columns. LC-MS is has been an important method for detecting new pharmaceuticals in the environment. (Batt, et al., 2008) A problem with LC-MS is the unknown effects of matrixes and their disturbance to the process. A way of compensating the loss is using internal standards in analysis. (Farré, et al., 2007) The principle of MS is to bombard the columns with electrons and ionize them. This way they break up into ionized fragments and the mass spectrometer can detect the mass of different compounds and identify them. (Swedish Environmental Protection Agency, Experimental part 9. Materials and methods
9.1 Objective of the SBR plant study
The results from the master's thesis made by Anna Lehtonen (2011) showed the difficulty of laboratory practices when measuring compounds in low concentrations (µg/l). In the thesis BPA and HHCB were added to a bioreactor to then find out how the added compound changed the microbial communities. Because only a fraction of the added BPA and HHCB concentration could be traced in the influent water, no definite conclusions could be made in the thesis. However, this finding emphasizes the importance of planning of experiments. (Lehtonen, 2011) The objective of the SBR study in this thesis is to trace the added marker compound so that laboratory practices can be verified. When this has been done, a preliminary estimation about the biodegradation rate and biodegradation rate constant of the chosen marker compound can be made. Also one of the main objectives of the thesis is to study the SBR plants operation and to optimize its parameters and functionality. 9.2 Marker compound
The criteria used in the selection of the marker compound were chosen basis on the literary review presented in the literature part in this thesis and the experiences in the master's thesis by Anna Lehtonen (2011). Ibuprofen was chosen because it met the criteria which made reliable measurements possible. The criteria used are described  A previously studied compound  Biodegradable, though not at a too fast rate  Does not sorb to sludge in significant amounts  Largely used in Finland  Have potentially harmful effects in nature Ibuprofen is a very common drug in Finland. It is used here more than in most other European countries. (Ternes, 2004) As described in Chapter 4.3.1, ibuprofen is

biodegradable in activated sludge and does not sorb in significant amounts to sludge. It is also a largely studied compound with biodegradation rate constants comparable to the ones obtained in this study. 9.3 The SBR laboratory plant
The experimental part of the thesis was made in a laboratory scale SBR pilot with four reactors where the biodegradation of ibuprofen was studied. The SBR was operating 2.11.2011-20.2.2012. The SBR arrangements are illustrated in Figure 7 and pictures in Figure 8. The parameters for the operation of the SBR were chosen after a literature study and to best represent the conditions found in Finnish WWTPs. At the beginning of the experiment, to get the reactors started, sludge from Suomenoja WWTP was added. After this, synthetic wastewater was fed to the reactors. The Suomenoja WWTP sludge was gradually replaced by synthetic sludge created in the process. The reactors had an operating volume of 12l and all four reactors operated independently from each other. They were kept in a temperature controlled room at a constant temperature of 12 ± 1°C. The temperature of 12°C was chosen because it is a typical wastewater treatment temperature in Finland and because this is a possible limit of nitrogen removal in the environmental permits of WWTPs. This is based on the European Union wastewater directive. (The Commission of the European Communities, One operating cycle lasted 8 hours, which meant a total of three cycles per day. The pumps and the aeration were controlled by a timer. The timer is seen in Figure 4. Figure 4 Picture of the timer that controlled the cycles in the reactors.

Every reactor had its own feeding pump and two reactors shared one draining pump. In each cycle three liters of synthetic wastewater was added to the reactors and in the decant stage an equal amount of cleaned water was removed. Sludge was wasted manually through a flexible hose at the bottom of the reactor as seen in Figure 5. A sludge age of 10 days was chosen because of a recommendation in the POSEIDON report where it was stated that many PHCs biodegrade best in WWTPs with SRTs of 10 days or more. (Ternes, 2004) This also enabled nitrification to take place in 12°C. (Henze et al. 2002) The SRTaer meant that sludge was wasted theoretically 750ml/day. In practice the sludge removal was manual and was removed 1875ml every Monday and Friday and 1500ml was removed every Wednesday. After the aeration time was lengthened on 16.1.2012, the SRTaer was 12 days. Figure 5 Pictures of the sludge wasting arrangement.
To provide oxygen and stirring, a ceramic aeration cube was placed in the bottom of each reactor as seen in Figure 6. The aeration took place only during the react stage. No additional mixture was needed because the aeration was enough to fully mix the tanks. The air to the aeration stone was provided by a compressor. The amount of Dissolved Oxygen (DO) was never under 4 mg/l for the entire cycle and during aeration the DO was around 10mg/l. The amount of oxygen was not controlled.

Figure 6 Pictures of the ceramic aeration cube in the bottom of the reactor and air rotameter.
Figure 7 Figure of the SBR arrangement.
Figure 8 Pictures of the SBR arrangement during aeration and settling.
The time for each stage in the SBR cycle was chosen based on a literary review. The cycle with each stage can be found in Figure 9 The process cycle from the beginning of the experiment to 13.1.2012.
The cycle was changed on 16.1.2012 due to problems with the operation. The second cycle can be found inand more about the challenges of operating the pilot can be found in Chapter 10. Figure 10 The process cycle from 16.1.2012 to the end of the experiment.
Before starting the reactors, assessments and calculations were made to analyze different scenarios. The settling of the sludge was seen as a risk. Preliminary calculations were made of how different organics loads could influence the MLSS concentration in the reactors. What that could have for consequences for the settling of sludge, together with possible Sludge Volume Index (SVI) values, was also analyzed. It was concluded that the organics load and composition in synthetic wastewater presented in Chapter 9.4 would lead to stable operation of the reactors. As the estimations made before the experiment varied from the actual values, the organics load was raised a couple of weeks into the experiment. More about the organics load is presented in the 9.4 Synthetic wastewater
Synthetic wastewater was prepared two times a week, every three or four days. The composition was the same as used in the master's thesis of Reetta Kuronen (2005). It was based on the wastewater composition of the Suomenoja and Viikinmäki WWTPs in Finland. (Kuronen, 2005) The composition was changed after a couple of weeks of operation. The pH in the reactors rose to 8.5 in the beginning of the experiment. Thus the amount of NaHCO3 was lowered twice; first the amount of NaHCO3 was lowered with 25% on 9.11.2011. Since this was insufficient, the amount was lowered from the original concentration with 43.75% on 25.11.2011. The amount of organic carbon was increased due to low yields and low MLSS. The amount of peptone and yeast extract was increased with 80% on 29.11.2011. After the changes, the pH in the reactors was 7.8 ± 0.2 and the MLSS rose. The complete recipe of the wastewater after all the changes had been made can be Table 15 Composition of synthetic wastewater after all the changes had been made
Composition of the synthetic wastewater added to the SBR (mg/l)
CH₃COONa * 3 H₂O Yeast extract (Mereck 3753) CaCl₂ * 2 H₂O MgSO₄ * 7 H₂O Nutrient solution Composition of nutrient solution (g/l)
FeCl₃ * 6 H₂O CuSO₄ * 5 H₂O (NH₄)Mo₇O₂₄ * 4 H₂O ZnSO₄ * 7 H₂O CoCl₂ * 6 H₂O In the beginning of the experiment, the average CODcr load was 320mg/l. When the synthetic wastewater was made, the CODcr load was 350mg/l but due to reactions in the synthetic wastewater tank, the composition of the water changed and the load decreased over time. The sources of organics were peptone, yeast extract and sodium acetate. Nutrients were also added to the wastewater. Nitrogen sources were yeast extract and ammonia. The conditions in the beginning of the experiment can be found in The HRT is calculated for the entire cycle. Table 16 Conditions in the beginning of the experiment
Aerated share of cycle g CODcr/ g MLVSS /d g CODcr/ g MLSS /d g BOD7(ATU)/ g MLVSS /d g BOD7(ATU)/ g MLSS /d The increase of peptone and yeast extract raised the CODcr and BOD7(ATU) loads. After the change in the composition of wastewater, the average CODcr load was 470mg/l. And the average BOD7(ATU) load was 370mg/l. The BOD7(ATU)/CODcr ratio was estimated to On 16.1.2012 the reaction time and therefore the aeration was lengthened with 45 minutes. The conditions in the reactors, after all the changes in the process, can be Table 17 Conditions in the end of the experiment
Aerated share of cycle g CODcr/ g MLVSS /d g CODcr/ g MLSS /d g BOD7(ATU)/ g MLVSS /d g BOD7(ATU)/ g MLSS /d 9.5 Storage solution of ibuprofen
A storage solution of ibuprofen was made by diluting 100mg of >98% ibuprofen (purchased from Sigma-Aldrich) in 100ml of methanol and then adding ultrapure water purified with reverse osmosis so that the stock solution had a total volume of 2l and an ibuprofen concentration of 50mg/l. The stock solution was stored in the dark at +4°C. Ibuprofen dissolved well in methanol, but after adding ultrapure water the solution turned foggy and white. After adding more methanol and letting the solution stand awhile the ibuprofen was again dissolved. However, before the third test some of the ibuprofen was again precipitated. A new stock solution was prepared on 13.01.2012. The second stock solution was stored and made in the same way as the first, with the exception of that the ibuprofen was first dissolved in 100ml of methanol and after that the ultrapure water was added. This time all the ibuprofen was dissolved and no precipitation occurred after the addition of ultrapure water. Before the two last tests the stock solution was taken to room temperature the day before and placed under mixing for the night. This ensured that all the ibuprofen was properly diluted in the stock 9.6 Sampling and analyses
9.6.1 Weekly process analyses
Samples from the process were taken once a week in the beginning of the experiment and every second week in the end of the experiment. Samples were analyzed to determine how the process was working. The analyses that were made on a regular basis are described i The results of the analyses can be found in Chapter 10. The CODcr and MLSS analyses were made more often because these were good indicators of how the process was working. Monitoring the organics removal in the reactors, ensured that the process was working as planned and the MLSS showed that the sludge was adapting well and producing new biomass. All analyses were made when the system was spiked with ibuprofen. The sludge was also observed via microscope. Table 18 Methods used in weekly analysis of conditions in the reactors
SFS-EN-ISO 11905-1 v.1998 + Standard Methods (v.2005) Lange: Ganimede N 4500 B. Ultraviolet Spectrofotometric Screening Method + Oxidation SFS-EN ISO 6878 v. 2004, measurment SFS-EN- Foss: FIAstar 5000 Analyzer ISO 15681-1, fia v. 2005 SFS-EN ISO 15681-1 v. 2005, tinchloride Foss: FIAstar 5000 Analyzer SFS-EN ISO 13395 v. 1997, fia Foss: FIAstar 5000 Analyzer SFS-EN ISO 13395, v. 1997 Foss: FIAstar 5000 Analyzer ISO 11732 v. 2005 Tecator 5012 Analyzer, 5042 Detector SFS-EN 872 v. 2005 SFS 5504 v. 1988WTW Applikationsbericht BSB 997 232 Respirometrische BSB₅-Bestimmung von mit hemmenden- oder toxischen stoffen belastetes Abwasser mit dem OxiTop- Meßsystem 9.6.2 Ibuprofen analysis
The influent water of the SBRs was spiked four times with ibuprofen during the experimental period. The spiking of influent were made on 30.11.2011, 19.12.2011, 25.1.2012 and 20.2.2012. The aims of the first test are listed below.  To determine the ibuprofen concentration in the storage solution, to see that the preparation of the storage solution had been done accurately.  To analyze a sample of influent wastewater to ensure that it has the intended concentration of ibuprofen. This was made to make sure that the correct measurements had been made and that the compound is not lost somewhere during the process.  To analyze one sample taken from a reactor during aeration to get a preliminary indication of how and if the compound biodegrades. The last three tests were made to determine a primary biodegradation rate and biodegradation rate constant of ibuprofen in a pilot scale SBR. In the second test, one reactor was left as a reference without spiked ibuprofen to ensure that no contamination was taking place during the sample taking and preparing. The samples were sent to another laboratory (Ramboll Analytics in Lahti) for analysis of ibuprofen. The results can be found in Chapter 10.2. The ibuprofen analysis made by Ramboll Analytics was done by the EPA Method 1694 Pharmaceuticals and Personal Care Products in Water, Soil, Sediment, and Biosolids by HPLC/MS/MS. (United States Environmental Protection Agency, 2007) The error of the analyses was estimated to be ca. 30% for both the sludge and water samples by the The water samples with relatively high concentrations could be analyzed by diluting straight to the right analyze interval. The water samples with low concentrations were concentrated before the analysis. A known concentration of deuterized ibuprofen was added to evaluate the yield of each analysis. The prepared sample was analyzed by UPLC-MS/MS technology and quantified according to the yield of the known The sludge samples, which were taken during aeration to determine the ibuprofen concentration in the reactors, at a certain point of time, were filtered after throughout mixing through a fiberglass filter (Schleicher & Schuell, GF 52 (Ref No. 10428230, 50 mm)). The solids were lightly rinsed with UHQ-water from the edges of the filter wall. The solids with the filters were dried in room temperature. The solids were eluated by putting them and a filter in a test tube, a known concentration of deuterized ibuprofen was added to this. This was then extracted by a precise amount of methanol. The extraction was made by first mixing the test tube for >60 minutes and then placing it in an ultrasound container. After the extraction, some of the methanol was taken and analyzed as the water samples. The ibuprofen in the sediment in the sludge samples were added to the results obtained from the analysis of the water phase in the sample. 10. Results and discussion
10.1 Operation of reactors
The primary goals for the SBRs were for them to remove organics from synthetic wastewater and nitrify. The four reactors were operated equally and the results show that the reactors worked as designed. The analyses showed that all four reactors had very similar organics and nutrient removals at all times. Nitrification was planned in the process and also realized. More of the nutrient removal is described in Chapter 10.1.3. The biggest change in the data occurred when the organics concentration in the synthetic wastewater was increased. This change can be seen especially in the organics and nitrogen concentrations in the reactors. A second change in the data can be observed when the pumping of influent water was ceased for a weekend 13.1-15.1.2012 due to surface sludge, that is generally caused by denitrification, and the potential problems that came with it. After this, it took some time for the process to recover. The sludge was settling well. The SVI values stayed under 100ml/g during the entire experimental period. This is a sign of a well settling sludge. (Metcalf & Eddy, 2003) 10.1.1 Biomass and activated sludge flocs
After the reactors were started, the sludge was first let to grow freely for one week. Regular sludge removal was started after that. The sludge however had a very low yield and under a microscope it was observed that very little microorganism were present in samples. This together with a decreasing MLSS concentration indicated that the sludge was not adapting well to the new surroundings. After lowering the pH on 25.11.2011 and increasing the organics load on 29.11.2011 the sludge seemed to start adapting better. A higher MLSS concentration was analyzed a week later on 7.12.2011. The change could also be observed via microscope where sludge samples had large clusters of vorticella present. A picture of a cluster of vorticella is seen in Figure 11 Picture of vorticella seen in a sample of well-adapted sludge via microscope 9.1.2012.
At the beginning of the experiment on 10.11.2011, the MLSS was 1.7g/l. This decreased to 1g/l due to low loads. When the organics load was increased, the MLSS rose to a level of 1.6g/l. The share of Volatile Suspended Solids (VSS) was in the beginning 75%. This amount increased during the experiment to almost 90% and was probably due to the lowered iron concentration in the sludge. The average MLSS and MLVSS concentrations are illustrated in Figure 12. Figure 12 The average of MLSS and MLVSS in the reactors during the experimental period. (The individual
values can be found in appendix 1)
The amount of SS in effluent wastewater was below 20mg/l even at the highest, which indicated that no large amount of sludge was escaping from the SBR with the effluent water. The average SS in the effluents are illustrated in Figure 13. Figure 13 The average SS concentration in effluent water. (The individual values can be found in appendix 1)
The total iron concentration in the sludge was analyzed regularly to detect how much of the original sludge had been replaced with the artificially grown sludge. As the sludge used in the start of the process was collected from Suomenoja WWTP, where iron is used for chemical phosphorus removal, the decreasing iron content was a good indication that the process had started producing new biomass and that the amount of Suomenoja WWTP sludge was gradually decreasing in the reactors. The total iron concentration decreased from over 120mg/l to 0.9mg/l during the experimental period and this is illustrated in Figure 14. Figure 14 The average total iron concentration in the reactors. (The individual values can be found in
appendix 1)
10.1.2 CODcr and BOD7(ATU)
The CODcr in both the influent and effluent water was measured regularly throughout the experimental period. The CODcr and the BOD7(ATU) in the influent wastewater depended somewhat on the difference in days when the synthetic wastewater was prepared and the day of sampling. The BOD7(ATU) in the influent and effluent wastewater was measured on two occasions at the end of the experiment to ensure that the BOD7(ATU) removal was sufficient and in line with the CODcr removal. The CODcr of the effluent wastewater was mainly between 50-100mg/l with an average of 89mg/l. This seemed to mostly depend on the influent CODcr load. The CODcr removal rates varied from 74-90% with an average of 83% for the entire experimental period. The CODcr removal is illustrated in Figure 15. Figure 15 The average CODcr removed. (Individual values of CODcr in influent and effluents can be found in
appendix 1)
The BOD7(ATU) of the effluent water was analyzed on 3.2.2012 and 14.2.2012. At the time of samplings, the effluent waters had a CODcr concentration of 50mg/l. The average BOD7(ATU) concentrations in the effluent wastewaters were 8mg/l. The BOD7(ATU) removal rates were about 96%. 10.1.3 Nutrient removal
Nutrient removal was not the primary goal when designing the SBRs. Both nitrogen and phosphorus were removed to some extent in the process. The removal could be mostly contributed to assimilation due to the microorganism growth. The removal rate for phosphorus varied between 15% and 40%. The phosphorus removal did not seem to be effected by the decreasing concentration of iron in the sludge or suspended solids concentration in the effluents. The average phosphorus removal is illustrated in Figure 16 Average total phosphorus removed.
All of the phosphorus in the effluent wastewater was present as phosphate. The phosphate was analyzed as soluble phosphate and the sample was filtered through a 0.45µm membrane. The phosphorus and phosphate concentrations in influents and effluents are illustrated in Figure 17 Average phosphorus and phosphate in influent and effluents. (Individual values can be found in
appendix 1)
The total nitrogen removal was more even than the phosphorus with removal of 30- 45%. The total nitrogen removal is illustrated in Even though the nitrogen load increased as the amount of carbon load was raised, the nitrogen removal stayed on the same level. The phosphorus and nitrogen concentrations in sludge are illustrated in Figure 18 The Average Ptot and Ntot concentrations in reactors. (Individual values can be found in appendix 1)
Figure 19 Average total nitrogen removed.
Ammonium was reduced in the reactors with indicates that the process was nitrifying even in the beginning of the experiment. All four reactors were nitrifying perfectly and the nitrification rate was over 99% through the entire experimental period. The ammonium concentration, together with the total nitrogen concentration in influents and effluents are illustrated in Figure 20 Average total nitrogen and ammonium in influent and effluents. (Individual values can be found in
appendix 1)
The amount of NO2 was measured on 8.2.2012 to ensure that most of the NO3+NO2 was nitrate. It was observed that 98% of the measured NO3+NO2 concentration was nitrate. The NO3+NO2 concentration through the experimental period is presented in Figure 21 Average NO3+NO2 in effluents. (Individual values can be found in appendix 1)
10.1.4 Denitrification
On 12.1.2012 the tubing of the influent wastewater feeding system was changed. There was some precipitate or biofilm formation in the tubes and to ensure that the concentration of the marker compound would not change, the tubing was changed. However, this obviously lead to a slightly increased organics load and the sludge was noticed to denitrify and rise up to the surface at the end of the cycle. A picture of the surface sludge is seen in Figure 22. There was a high risk that the sludge would accidentally be removed from the reactors during the decant stage. This was observed on 13.1.2012. The pumping of influent wastewater was ceased as this was observed on a Friday afternoon and aeration was put on for the weekend. On Monday 16.1.2012 the process was started again with a lengthened aeration period and a shortened settling time. The aeration time was increased with 45 minutes and settling time decreased respectively. This way the reactors were given more time to use the total organics load fed into the system. Also the settling time, which made possible the anoxic conditions causing denitrification, was shortened. The feeding tubes were again changed on 15.2.2012 prior to the last test. This time surface sludge was also observed in the reactors. This time, however, no additional steps were taken to hinder this, as the problem was not as severe as before. This meant that no risk of the sludge to be accidentally removed from the reactors during the draw stage was expected. Surface sludge was not observed after the process had adapted to the new conditions. Figure 22 Picture of the sludge raised to surface due to denitrification on 13.1.2012.
10.2 Ibuprofen
10.2.1 The first spiking of ibuprofen
The first wastewater spiked with ibuprofen was added to the process on 30.11.2011. A volume of 20ml stock solution was added to 50l of synthetic wastewater so that the final calculated ibuprofen concentration added to the reactors was 20µg/l. This meant that the calculated ibuprofen concentration in the reactors at the beginning of the aeration stage would be 5µg/l. A sample of the stock solution, spiked synthetic wastewater and sludge were sent to Ramboll Analytics to be analyzed. The sludge sample was removed from reactor 1, 200 minutes after the start of the aeration stage. The samples of sludge and synthetic wastewater were preserved by adding HCl to lower the pH to 3. The samples were stored in +4°C until analysis. The results from the first test can be found in The amount of ibuprofen in the storage solution was as intended 50mg/l. Also the amount of ibuprofen in the influent wastewater was analyzed to be 24µg/l ± 30% so the calculated concentration of 20µg/l fits within this margin. Calculating from this, the initial amount of ibuprofen in the beginning of the aeration was 6µg/l. The initial sludge sample indicated that the compound biodegrades fast in the reactor, up to 98% in 200 minutes. Although not enough data was obtained to further determine the biodegradation of ibuprofen, this test ensured that spiking and sampling procedures were done accurately enough. Table 19 Results from the first spiking of ibuprofen on 30.11.2011
Influent
10.2.2 The second spiking of ibuprofen
The second spike of ibuprofen was added to the pilot on 19.12.2011. During the second test, all changes to the synthetic wastewater had been made, see Chapter 9.4. Reactor 2 was not spiked with the compound, but left for control to ensure that no contamination was taking place during testing, sample preparation and analysis. A volume of 100ml stock solution was added to 50l synthetic wastewater. The target concentration of ibuprofen in the influent water was therefore 100µg/l and the calculated concentration in the reactors was 25µg/l at the beginning of the aeration. Samples of both the spiked and not spiked synthetic wastewaters were sent for analysis. Also four sludge samples, from reactor 1, taken at different times, and a sample of effluent were sent for analysis. A sludge sample from reactor 2 was also analyzed to check for contamination. All samples were preserved by lowering the pH to 3 with HCl and stored in +4°C until The results from the second adding of ibuprofen to the reactor can be found in an This time the influent wastewater sample was taken directly from the feeding tube and this might have been a reason for why the ibuprofen concentration was lower in the second test. Some of the compound might have got stuck or already biodegraded in biofilm and other accumulations in the feeding tubes. Totally 65% of the added ibuprofen was caught in the influent wastewater when analyzed. This meant that the starting concentration in the SBR reactor was 16µg/l ± 30% instead, of the calculated 25µg/l. The sludge samples, taken at different times in the aeration period, indicate that the ibuprofen biodegrades in the reactors, but not as much as the first test showed. A significant concentration of the compound was also found in the effluent wastewater which means that the reactor did not biodegrade all of the ibuprofen but only around 53% of the initial concentration. The control samples did not contain ibuprofen which means that no contamination was taking place during the testing, sampling or analysis. A specific biodegradation rate was calculated to be 1.6µg ibuprofen/gVSS/h. Table 20 Results from the second test on 19.12.2011
Added and analysed concentration of ibuprofen in influent water
Influent (control) Analysed concentrations of ibuprofen in reactors
Minutes into the Concentration in Concentration in reactor 1 (µg/l) reactor 2 (µg/l) Ibp concentration in effluent water Figure 23 Ibuprofen concentration change in reactor 1 on 19.12.2011.
10.2.3 The third spiking of ibuprofen
The third test was made on 25.1.2012. By this time all changes to the process had been made and the conditions in the SBRs can be found in This time all four reactors were spiked with the same amount of ibuprofen. This way a more reliable statistical evaluation of the biodegradation could be calculated. Synthetic wastewater spiked with 100µg/l ibuprofen was added to all four reactors. Two influent water samples were sent for analysis. One of the influent water samples was taken at the end of the feeding tube and the other directly from the synthetic wastewater tank. All in all 16 sludge samples and 4 effluent water samples were also sent for analysis. All samples were preserved by lowering the pH to 3 with HCl and stored in +4°C until analysis. The complete results from the third test can be found in Table 21 and Figure 24. The influent wastewater sample was taken directly from the feeding tube of reactor 2. This meant that influent water was manually added to the reactor 2. The four sludge samples were taken at the same times as in the second test. This time the yield of ibuprofen was over 90% of the added amount in the synthetic wastewater, in the influent wastewater analysis. It was however noted that the error in analysis is most likely larger than the ones that result from the spiking procedures, so the calculated influent concentration of 100µg/l was used in all further calculations. As the tubing had been changed before the test, no ibuprofen was believed to be stuck in biofilm in the tubes. The sample taken 15 minutes after the beginning of aeration was not considered in the calculation of biodegradation rate constant. The results indicate that the compound had not, at this point, been evenly mixed in the tank, which made this data unreliable. The changes in the ibuprofen concentrations are similar in all reactors. The biodegradation that took place, varied from 52-56%, where reactor 1 had the lowest removal. The degraded amount of the compound is similar to detected amount in the second test, where the degradation was about 53%. The specific biodegradation rate was calculated to be 1.9, 2.1, 1.5 and 1.5µg ibuprofen/gVSS/h for reactors 1 ,2 ,3 and 4 Table 21 Results from the third test on 25.1.2012
Added and analysed concentration of ibuprofen in influent water
Influent in reactor 2 Influent in reactors 1, 3 and 4 Analysed concentrations of ibuprofen in reactors
Minutes into the Concentration in Concentration in Concentration in Concentration in reactor 1 (µg/l) reactor 2 (µg/l) reactor 3 (µg/l) reactor 4 (µg/l) Ibp concentration in effluent water Figure 24 Ibuprofen concentration change in all four reactors on 25.1.2012.
10.2.4 The fourth spiking of ibuprofen
The fourth adding of ibuprofen in the reactors was made on 20.2.2012. The goal in this test was to repeat the experiment made last time and verify the data. This time analyses were only made of two reactors, reactors 1 and 2. The influent water sample was taken from the end of reactor 3 feeding tube. All tubing was changed before the experiment to ensure that ibuprofen would not react or sorb due to the biofilm in the feeding tubes. Also, to save analysis costs, only 3 sludge samples from each reactor were sent for analysis. The samples from the reactors were taken at 60, 180 and 300 minutes after the beginning of aeration. As in the previous test, the synthetic wastewater was spiked with ibuprofen so that the calculated concentration was 100µg/l in the influent water and 25µg/l in the reactors at the beginning of aeration. As in the third test, the calculated concentration in the influent was used in the further calculations of biodegradation rate and biodegradation rate constant. In the fourth test the biodegradation rate seemed to be lower than in the previous ones. The compound degraded 36% in reactor 1 and 28% in reactor 2. The results from the fourth test are presented in and The specific biodegradation rate was calculated to be 0.9µg ibuprofen/gVSS/h for both reactors. Table 22 Results from the test on 20.2.2012
Added and analysed concentration of ibuprofen in influent water
Analysed concentrations of ibuprofen in reactors
Minutes into the Concentration in Concentration in reactor 1 (µg/l) reactor 2 (µg/l) Ibp concentration in effluent water Figure 25 Ibuprofen concentration change in reactor 1 and reactor 2 on 20.2.2012.
10.2.5 Biodegradation of ibuprofen
According to the literary review presented in Chapter 4.3.1 it was expected that ibuprofen would biodegrade. The biodegradation and biodegradation rate constant were determined as explained in Chapter 3.3.1. The biodegradation of ibuprofen is seen as a pseudo first order degradation. In the first test, enough data was not obtained to determine a biodegradation rate and biodegradation rate constant. In the second, third and fourth tests, these could be calculated. As mentioned in Chapter 10.2.3, the sampling point at 15 minutes after the beginning of aeration was not considered in the calculations of the constant. As the biodegradation of the compound was seen as a pseudo first order degradation, where the degradation depended on the amount of MLSS in the reactors, the concentrations of ibuprofen in the reactors (as ln(C0/Ca)) were plotted as a function of time. The plots are presented in Figures 26, 27 and 28. A linear trend line was added to the plot. The slope k´ of the trend line was divided by the MLSS concentration in the reactor to obtain the biodegradation rate constant kbiol. Figure 26 Trend line from the second test 19.12.2011.
Figure 27 Trend lines from the third test 25.1.2012.
Figure 28 Trend lines from the fourth test 20.2.2012.
From the obtained kbiol values from each test, an average constant was calculated that describes the biodegradation of ibuprofen in the SBR in the temperature of 12°C. A summary of the gained constants is presented in The average biodegradation rate constant with the minimum, maximum and standard deviation is presented in The average specific biodegradation rate is presented in Table 25. Table 23 Summary of the biodegradation rates and biodegradation rate constants obtained in the study
Specific biodegradation rate
MLSS (g/l)
Biological transformation (µg ibuprofen/gVSS/h)
Table 24 The average biodegradation rate constant with standard deviation and minimum and maximum
values
Table 25 Average specific biodegradation rate obtained in the study with standard deviation and minimum
and maximum values
Specific biodegradation rate
10.2.6 Comparing the results to literature
Values found in literature for kbiol were a bit higher than the ones obtained in this study. This could be a result of many different factors. As studies do not contain all the background information needed to compare the differences, no conclusive comparison can be made. In the study made by Joss et al. (2006) enough information was available to make some speculations. The study is presented in Chapter 4.3.1 and a summary of the conditions in that experiment and this, is presented in Table 26. In the study they obtained the highest biodegradation rates, the MLSS was over double that of this study. Also the influent water had a lower CODcr load and the temperature was higher. Table 26 Summary of the conditions in experiments made by Joss et al. (2006) and this study
MLSS (g/l) COD (mg/l)
Joss et al. (2006) As Clara et al. (2005) concluded that the temperature should not have big effect on the biodegradation of ibuprofen, it is more likely that the SRT and organics load had a larger effect on the results. This could also explain the big difference between the results obtained in the first and three last tests. For conclusive answer to this question, more study is needed. Another factor that seemed to influence the biodegradation was the MLSS concentration. Another factor that could have influenced the lower biodegradation rate constants was that the sludge in this study was not accustomed to ibuprofen when it was spiked with the compound. In the other studies that have been presented the sludge was accustomed 11. Conclusions
Potentially harmful compounds are a growing interest among researchers. While it has been known since the last century that POPs cause damage to the environment, new emerging pollutants are being constantly detected. Many man-made compounds have been found to have endocrine disruptive tendencies and to pose a threat to the reproductive systems of animals. As many of the PHCs are present in household products such as plastic, electronics and personal care products, the exposure to these happens mostly before ending up in waters via WWTPs. To control their distribution at source and forbid their use seems like a safer and environmentally friendlier option. Pharmaceuticals are a different challenge as, contrary to other PHCs, their use is hard to restrict and replace with other compounds. Other ways to reduce their presence and threat to the environment needs to be studied. A special threat is antibiotics and anti- microbial compounds as their presence in the environment increase the risk of antibiotic resistant bacteria being formed. Biodegradation is the most preferable way of removing PHCs from wastewater because this is the only way of ensuring that they do not end up in the environment. Problems arise when PCHs sorb to sludge and the sludge is used in agriculture and other ways relocated into the environment. Measuring and analyzing compounds at concentrations of µg/l is challenging. The analyzing equipment and procedures will hopefully improve in the future and make this sort of study easier to a wide range of compounds. A lot is still unknown about the microorganisms and conditions behind biodegradation. This results in that it is not known if and what advanced treatments are needed to keep the environment safe from harmful compounds. Activated sludge, when process conditions are optimized, is a strong candidate for obtaining good results in PHC-removal. The cold conditions that are present in Finnish WWTP may slow the biodegradation of certain compounds. To understand the fate of PHCs in the special conditions that prevail in the Nordic countries more study is needed. In this study, it could be determined that ibuprofen is biodegraded in SBRs without an adaptation period. The first test made in this research implied that ibuprofen was biodegraded up to 98%, while the future tests implied that only around 30-50% is biodegraded. The cause of this is not known. A possibility however is that while the SBRs had a lower organics load in the first test than in the rest, the process could better use up the ibuprofen. The biodegradation rate constants obtained in the SBRs are a bit lower than those found in literature. This can be a result of a number of things. The SBRs were working in cold temperature, had a sludge age of only 12 days and the reactors were not accustomed to ibuprofen as it was not constantly fed into the system. The reactors had also a high F/M- ration. A weakness of the biodegradation rate constant is that it only is valid for the specific conditions where it is determined. But it gives a good indication of the biodegradation potential. Literature values are hard to compare with each other as they are obtained in very different ways and all test conditions are not fully documented. A big uncertainty in the results was the margin of error in the analysis. As it was so large, exact concentrations were not known. Hopefully the analysis will in future be more precise and exact biodegradation rates and constants could be determined. If ibuprofen was mineralized or turned into other compounds was not studied in the experiments. So it is not known if the compound is really biodegraded or if its metabolites are let to nature where they can metabolize to the parent compound. It was also not studied if the biodegradation of ibuprofen was through co-metabolism or catabolic metabolism. Most studies only analyze one compound at a time. Knowledge of synergy effects and actual behavior of different compounds in mixtures are scarce. Synergy effects can have huge implication on compounds behavior in WWTPs and the harmful effects to the environment. 11.1 Future research areas
There are many questions to be answered to better understand the effects of PHCs in the environment and how these can be reduced in WWTPs. How and by which microorganisms different compounds are degraded can give a better insight to what kind of conditions are needed in WWTPs to optimize the biodegradation. Another way to determine the optimal WWTP conditions for PHC-removal would be to study how SRT, temperature and organics load effect biodegradation of a compound. This could be studied in both conventional activated sludge and more advanced treatments. By comparing the difference in biodegradation, costs and environmental impacts, the use of advanced treatments could better be considered. Using and building more advanced treatments to WWTP can results in extremely high costs and increased greenhouse gas emissions. The benefits of reducing the concentrations of PHCs by advanced treatments may be overshadowed by the negative impacts of implementing them. As many of the compounds are poorly biodegradable and sorb to sludge, the sludge treatment and the possibilities there to reduce the amount of PHCs there would be important to study. This could ensure safer sludge disposal and reuse. Another interesting aspect is the rising concern over antibiotics in WWTPs and the environment. An interesting question to study would be how antibiotics impact the bacterial community in WWTPs. Do they alter the bacterial community in any way and does antibiotic resistance in bacteria increase in WWTPs where antibiotics are present? Also the threat antimicrobial compound like triclosan might impose in reference to antibiotic resistant bacteria is an unanswered question. The amount of pharmaceuticals in the effluents from pharmaceutical factories has not traditionally been seen as a large source of pharmaceuticals. Bigger interests have been municipal WWTPs and hospital wastewaters. An interesting research area would be to study the effluents from pharmaceutical factories. This can be very important to study, especially in countries where wastewaters from industries are not properly treated. References
Albrecht, M. A., Evans, C. W. & Raston, C. L., 2006. Green chemistry and the health implications of nanoparticles. Green Chemistry , Volume 8, pp. 417-432. Batt, A. L., Kim, S. & Aga, D. S., 2006. Enhanced Biodegradation of Ioromide and Trimethroprim in Nitrifying Activated Sludge. Environmental Science Technology , Volume 40, pp. 7367-7373. Batt, A. L., Kostich, M. S. & Lazorchak, J. M., 2008. Analysis of Ecologically Relevant Pharmaceuticals in Wastewater and Surface Water Using Selective Solid-Phase Extraction and UPLC-MS/MS. Analytical Chemistry , Volume 80, pp. 5021-5030. Beruetta, L., Gallo, B. & Vicente, F., 1995. A Review of Solid Phase Extraction: Basic Principles and New Developments. Chromatographia , Volume 40, pp. 474-483. Bitton, G., 2005. Wastewater Microbiology. 3rd ed. New Jersey: Jhon Wiley & Sons. Bolong, N., Ismail, A., Salim, M. & Matsuura, T., 2009. A review of the effects of emerging contaminants in wastewater and options for their removal. Desalination , Volume 239, pp. 229-246. Brorström-Lundén, E, Svenson, A, Viktor, T, Woldegiorgis, A, Remberger, M, Kaj, L, Dye, C, Bjerke, A & Schlabach, M 2008. Measurments of Sucralose in the Swedish Screening Program 2007 -Part I', IVL Report B1769, Swedish Environmental Research Institute, Stockholm. Carballa, M., Omil, F. & Lema, J. M., 2007. Calculation Methods to Perform Mass Balances of Micropollutants in Sewage Treatment Plants. Application to Pharmaceuticals ans Personal Care Products (PPCP). Enviromental Science and Technology, Volume 41, pp. 884-890. Chen, X, Lund Nielsen, J, Furgal, K, Liu, Y, Lolas, IB & Bester, K 2011. Biodegradation of triclosan and formation of methyl-triclosan in activated sludge under aerobic conditions. Chemosphere, Volume 84, pp. 452-456. Clara, M, Strenn, B, Gans, O, Martinez, E, Kreuzinger, N & Kroiss, H 2005. Removal of selected pharmaceuticals, fragrances and endocine disrupting compounds in a membrane bioreactor and conventional wastewater treatment plants. Water Research, Volume 39, no. 19, pp. 4797-4807. Combalbert, S. & Hernandez-Raquet, G., 2010. Occurance, fate, and biodegradation of estrogens in sewage and manure. Applied Microbiology Biotechnology , Volume 86, pp. Det Norske Veritas, 2006. Kartlegging av utvalgte forbindelser i legemidler og kosmetikk, Oslo: Det norske Veritas. Bisphenol [Accessed 20 12 2011]. European Union-Risk Assesment Report, 2008. 1,3,4,6,7,8-HEXAHYDRO-4,6,6,7,8,8- [Accessed 4 October 2011]. Farré, . M., Petrovic, M. & Barceló, D., 2007. Recently developed GC/MS and LC/MS methods for determining NSAIDs in water samples. Analytical Bioanalytical Chemistry, Volume 387, pp. 1203-1214. Fatta-Kassinos, D., Meric, S. & Nikolaou, A., 2011. Pharmaceutical residues in environmental waters and wastewater: current state of knowledge and future research. Analythical Bioanalythical Chemistry , Volume 399, pp. 251-275. Federle, T. W., Kaiser, S. K. & Nuck, B. A., 2002. Fate and effects of triclosan in activated sludge. Environmental Toxicology and Chemistry , Volume 21, pp. 1330- Finnish Medicines Agency, 2011. Lääkekulutus vuosina 2007 - 2010, Helsinki Finnish Ministry of Environment, 2010. Miten nanohiukkaset käyttäytyvät joutuessaan luontoon?. [Accessed 21 12 2011]. Finnish Ministry of the Environment, 2005. Vesiympäristölle haitalliset ja vaaralliset aineet pintavesissä, Helsinki: Edita Prima Oy. Finnish Ministry of the Environment, 2010. Bromatut palonestoaineet. [Online] [Accessed 28 10 2011]. Suomenojan prosessikaavio. vio_suomenoja.pdf [Accessed 21 12 2011]. Henze, M., Harromöes, P., la Cour Jansen, J. & Arvin, E., 2002. Wastewater Treatment: Biological and Chemical Processes. 3rd ed. Berlin: Springer-Verlag. Johnson, AC, Aerni, -R, Gerritsen, A, Gibert, M, Giger, W, Hylland, K, Juergens, M, Nakari, T, Pickering, A, Suter, MJ-F, Svenson, A & Wettstein, FE 2005. Comparing steroid estrogens, and nonylphenol content across a range of European plants with different treatment and management practicies. Water Research, Volume 39, pp. 47-58. Jones, O. A., Green, P. G., Voulvoulis, N. & Lester, J. N., 2007. Questioning the Excessive Use of Advanced Treatment to Remove Organic Micropollutants from Wastewater. Environmental Science and Technology, Volume 41, pp. 5085-5089. Jones, O. A. H., Volvoulis, N. & Lester, J., 2005. Human Pharmaceuticals in Wastewater Treatment Processes. Environmental Science and Technology, Volume 35 Joss, A, Zabczynski, S, Göbel, A, Hoffman, B, Löffler, D, McArdell, CS, Ternes, TT, Thomsen, A & Siegrist, H 2006. Biological degradation of pharmaceuticals in municipal wastewater treatment: Proposing a classification scheme. Water Research, Volume 40, pp. 1686-1696. Khan, S., Mukherjee, A. & Chandrasekaran, N., 2011. Silver nanoparticles tolerant bacteria from sewage environment. Journal of Environmental Sciences , Volume 23, pp. Kidd, KA, Blanchfield, MH, Palace, PV, Evans, RE, Lazorchak, JM & Flick, RW 2007. Collapse of a fish population after exposure to a syntetic estrogen. PNAS Volume 104 No 21, pp. 8897-8901 Kim, D., Park, C.-S., Murayama, M. & Hochella, M. F. J., 2010. Discovery and characterization of silver sulfide nanoparticles in final sewage sludge products. Environmental Science & Technology , Volume 55, pp. 7509-7514. Kim, S. & Aga, D. S., 2007. Potential Ecological and Human Health Impacts of Antibiotics and Antibiotic-Resistant Bacteria From Wastewater Treatment Plants. Journal of Toxicology and Environmental Health, Volume 10, pp. 559-573. Korkki, K., 2006. Perfluorattujen alkyyliaineiden (PFAS) aiheuttamat ympäristöriskit Suomessa, Helsinki: Edita Prima Oy. Koskinen, P, Silvo, K, Mehtonen, J, Ruoppa, M, Hyytiä, H, Silander, S & Sokka, L 2005. Esiselvitys tiettyjen haitallisten orgaaniste aineiden päästöistä, Suomen Ympäristökeksus, Helsinki. Kraigher, B, Kosjek, T, Heath, E, Kompare, B & Mandic-Mulec, I 2008. Influence of pharmaceutical residues on the structure of avtivated sludge bacterial communities in wastewater treatment bioreactors. Water Research, Volume 42, pp. 4578-4588. Kummerer, K., Menz, J., Schubert, T. & Thiemelans, W., 2011. Biodegradability of organic nanoparticles in the aqueous environment. Chemosphere , Volume 82, pp. Kupper, T, Plagellat, C, de Alencastro, LF, Grandjean, D & Tarradellas, J 2006. Fate and removal of polycyclic musks, UV filters and biocides during wastewater treatment. Water Research, Volume 40, pp. 2603-2612. Kuronen, R., 2005. Enhancing wastewater nitrogen removal in activated sludge process by using natural zeolites, Espoo Larsson, J., de Pedro, C. & Paxeus, N., 2007. Effluent from drug manufacturers contains extremely high levels of pharmaceuticals. Journal of Hazardous Materials , Volume 148, pp. 751-755. Lehtonen, A., 2011. Changes in microbial diversity of biological carrier reactor removing organic detrimental elements, Espoo Lindberg, RH, Wennberg, P, Johansson, MI, Tysklind, M & Andersson, BA 2005. Screening of Human Antibiotic Substances and Determination of Weekly Mass Flows in Five Sewage Treatment Plants In Sweden. Environmental Science & Technology Volume 39, pp. 3421-3429. Lischman, L, Smyth, SA, Sarafin, K, Kleygwegt, S, Toito, J, Peart, T, Lee, B, Servos, M, Beland, M & Seto, P 2006. Occurence and reductions of pharmaceuticals and personal care products and estrogens by municipal wastewater treatment plants in Ontario, Canada. Science of the Total Environment, Volume 367, pp. 544-558. Liu, Z.-h., Kanjo, Y. & Mizutani, S., 2009. Removal mechanisms for endorcine disrupting compounds (EDCs) in wastewater treatment-physical means, biodegradation, and chemical advanced oxidation: A review. Science of the Total Environment, Volume 407, pp. 731-748. Loos, R, Gawlik, BM, Boettcher, K, Locoro, G, Contini, S & Bidoglio, G 2009. Sucralose screening in European surface waters using a solid-phase extraction-liquid chromatography–triple Chromotography A, Volume 1216, pp. 1126-1131. Mace, S. & Mata-Alvarez, J., 2002. Utilization of SBR Technology for Wastewater Treatment: An Overwiew. Industria &l Engineering Chemistry Research, Volume 41, Malmi, H. & Mannio, J., 2008. Haitallisten aineiden näytteenotto ja esiintyminen jätevedenpuhdistamoilla, Helsinki: Suomen Ympäristökeskus. Marttinen, S. K., Kettunen, R. H., Sormunen, K. M. & Rintala, J. A., 2003. Removal of bis(2-ethylhexyl) phthalate at a sewage treatment plant. Water Research , Volume 37, Maurer, M, Escher, BI, Richle, P, Schaffer, C & Adler, AC 2007. Elimination of β- blockers in sewage treatment plants. Water Research, Volume 41, pp. 1614-1622. Metcalf & Eddy, 2003. Wastewater Engineering; Treatment and Reuse. 4th ed. New York: McGraw Hill. Mueller, N. C. & Nowack, B., 2008. Exposure modelling of engineered nanoparticles in the environment. Environmental Science & Technology , Volume 42, pp. 4447-4453. New England Interstate Water Pollution Control Commission, 2005. Sequencing Batch Reactor Desing and Operational Considerations, Massachusetts Paxéus, N., 2004. Removal of selecten non-steroidal anti-inflammatory drugs (NSAIDs), gemifibrozil, carbamazepine, beta-blockers, trimethroprim and triclosan in conventional wastewater treatment plants in five EU countries and their discharge to the aquatic environment. Water Science and Technology , Volume 50, pp. 153-260. Racz, L. & Goel, R. K., 2010. Fate and removal of estrogens in municipal wastewater. Journal of Environmental Monitoring,Volume 12, pp. 58-70. Radjenovic, J., Petrovic, M. & Barcelo, D., 2009. Fate and distribution of pharmaceuticals in wastewater and sewage sludge of the concventional activated sludge (CAS) and advanced bioreactor (MBR) treatment. Water Reasearch , Volume 43, pp. Rang, H. P., Dale, M., Ritter, J. & Moore, P., 1995. Pharmacology. 5th ed. Loanhead: Roh, H, Subramanya, N, Zhao, F, Yu, C-P, Sandt, J & Chu, K-H 2009. Biodegradation ammonia-oxidizing Chemosphere,Volume 77, pp. 1084-1089. Roslev, P, Vorkamp, K, Aarup, J, Fredriksen, K & Nielsen, PH 2007. Degradation of phthalate esters in an activated sludge wastewater treatment plant. Water Research, Volume 41, pp. 969-976. RPA, 2005. Risk assessment studies on targeted consumer applications of certain organotin compounds, Norfolk: RPA. Sáez , M., de Voogt , P. & Parsons, J. R., 2008. Persistence of perfluoroalkylated substances in closed bottle test with municipal sewage sludge. Environ Sci Pollut Res 15, pp. 474-477. Scott Fogler, H., 2009. Elements of Chemical Reaction Engineering. Westford: Pearson Shaar, H., Clara, M., Gans, O. & Kreuzinger, N., 2010. Micropollutants removal during biological wastewater treatment and a subsequent ozonation step. Environmental Pollution , Volume 158, pp. 1399-1404. Sinclair, E. & Kannan, K., 2006. Mass Loading and Fate of Perfluoroalkyl Surfactants in Wastewater Treatment Plants. Environmental Science & Technology , Volume 40, Smook, T., Zho, H. & Zytner, R. G., 2008. Removal of ibuprofein from wastewater - comparing biodegradation in conventional, membrane bioreactor and biological nutrient systems. Water Science & Technology, Volume 57, pp. 1-8. Soares, A, Guieysse, B, Jefferson, B, Cartmell, E & Lester, JN 2008. Nonylphenol in the environment: A critical review on occurence, fate, toxicity and treatment in wastewaters. Environment International, Volume 34, pp. 1033-1049. Soh, L., Connors, K. A., Brooks, B. W. & Zimmerman, J., 2011. Fate of Sucralose through Environmental and Water Treatment Processes and Impact on Plant Indicator Species. Environmental Science and Technology , Volume 45, pp. 1363-1369. Solen, K. A. & Harb, J., 2011. Introduction to Chemical Engineering; Tools for Today and Tomorrow. 5th ed. Hoboken, NJ: Wiley. Stasinakis, A. S., Thomaidis, N. S., Nikolaou, A. & Kantifes, A., 2005. Aerobic biodegradation of organotin compounds in activated sludge batch reactors. Environmental Pollution , Volume 134, pp. 431-438. Stockholm Convention, 2009. Supporting document for the risk profile on short- [Accessed 19 January 2012]. [Accessed 28 October 2011]. Suárez, S., Carballa, M., Omil, F. & Lema, J. M., 2008. How are pharmaceuticals and personal care products (PPCPs) removed from urban wastewaters?. Reviews in Environmental Science and Biotechnology , Volume 7, pp. 125-138. Swedish Environmental Protection Agency, 2004. Persistent Organic Pollutants, A Swedish View of an International Problem. Värnamo: Fälth & Hässler. Swedish Environmental Protection Agency, 2008. Avloppsreningsverkets förmåga att ta hand om läkemedelsrester och andra farliga ämnen, Stockholm: Swedish Environmental Protection Agency. SYKE, 2008. PFOS-yhdisteiden käyttökielto voimaan 27. kesäkuuta. [Online] [Accessed 4 October 2011]. Ternes T.A., 2004. Assessment of Technologies for the Removal of Pharmaceuticals and Personal Care Products in Sewage and Drinking Water Facilities to Improve the Indirect Potable Water Reuse. Project acronum POSEIDON. Ternes, T. A. & Hirsch, R., 2000. Occurence and Behaviour of X-ray Contrast Media in Sewage Facilities and Aquatic Environment. Environmental Science & Technology , Volume 34, pp. 2741-2748. The Commission of the European Communities, 1998. COMMISSION DIRECTIVE 98/15/EC of 27 February 1998 amending Council Directive 91/271/EEC with respect to certain requirements established in Annex I thereof. Official Journal of the European Communities, Issue 67, pp. 29-30. Thomas, P. M. & Foster, G. D., 2005. Tracking acidic pharmaceuticals, caffeine, and triclosan through the wastewater treatment process. Environmental Toxicology and Chemistry, Volume 23, pp. 25-30. Torres, CI, Ramakrishna, S, Chiu, C-A, Nelson, KG, Westerhoff, P & Brown- Krajmalnik, R 2011, 'Fate of Sucralose During Wastewater Treatment', Environmental Engineering Science, Volume 28, pp. 325-331. United States Environmental Protection Agency, 2009. Short-Chain Chlorinated Paraffins (SCCPs) and Other Chlorinated Paraffins Action Plan. [Online] [Accessed 27 12 2011]. United States Environmental Protection Agency, 1999. Sequencing Batch Reactors. Washington: Office of Water. United States Environmental Protection Agency, 2007. Method 1694: Pharmaceuticals and Personal Care Products in Water,Soil, Sediment, and Biosolids by HPLC/MS/MS, Washington: EPA-821-R-08-002. Urase, T. & Kikuta, T., 2005. Separate estimation of adsorption and degradation of pharmaceutical substances and estrogens in the activated sludge process. Water Research, Volume 39, pp. 1289-1300. Vesilind, A. P., 2003. Wastewater Treatment Plant Design. London: IWA Publishing. Wick, A, Fink, G, Joss, A, Siegrist, H & Ternes, TA 2009, 'Fate of beta blockers and psycho-active drugs in conventional wastewater treatment', Water Research, Volume 43, pp. 1060-1074. Vieno, N., 2007. Occurence of Pharmaceuticals in Finnish Sewage Treatment Plants, Surface Waters, and Their Elimination in Drinking Water Treatment Processes, Tampere: Tampere University of Technology. Vieno, N. M., Tuhkanen, T. & Kronberg, L., 2006. Analysis of neutral and basic pharmaceuticals in sewage treatment plants and in recipient rvers using solid phase extraction and liquid chromotography-tandem mass spectrometry detection. Journal of Chromotography A, Volume 1134, pp. 101-111. Vieno, N., Tuhkanen, T. & Koronberg, L., 2007. Elimination of pharmaceuticals in sewage treatment plants in Finland. Water Research , Volume 41, pp. 1001-1012. Wilderer, P. A., Irvine, R. L. & Goronszy, M. C., 2001. Sequenscing Batch Reactor Technology, s.l.: IWA Scientific and Technical Report Series. VVY, 2008. Haitallisten aineiden esiintyminen suomalaisissa yhdyskuntajätevesissä-E- PRTR-selvityksen tulokset. Helsinki: VVY. Zang, Y., Greissen, S.-U. & Gal, C., 2008. Carbamazepine and diclofenac: Removal in wastewater treatment plants and occurence in water bodies. Chemosphere , Volume 73, Zeng, L, Wang, T, Wang, P, Liu, Q, Han, S, Yuan, B, Zhu, N, Wang, Y & Jiang, G 2011. Distribution an Trophic Transfer of Short-Chain Chlorinated Paraffins in an Aquatic Ecosystem Receiving Effluents from a Sewage Treatment Plant. Environmental Science & Technology, Volume 45, pp. 5529-5535. Appendix I
Appendix II
Planning and operating a pilot scale Sequencing Batch Reactor (SBR) Planning
When planning a SBR many things need to be taken into considerations. The most important are listed below.  Number and operating volume of the reactors  Operating cycle  Pumps and tubing  Timers  Influent and effluent water  Sludge age and sludge wasting  Aeration and mixing  Cleaning and maintenance of the SBRs  The SBRs on weekends and holidays  pH  Nitrification and denitrification Reactors and operating cycle
The number of reactors depends on the purpose of the SBRs. Many reactors enable parallel tests to be made or the operation of multiple reactors at different conditions. The operating volume of the reactors depends on the purpose of the SBRs and on the equipment available. Smaller sized SBRs can be easier operated manually without many pumps. If the operating volumes grow, larger and more complicated equipment are needed. In the Water Laboratory at Aalto University 4 reactors are available, these work well when the operating volume is around 10-12 liters. The four reactors are presented in Figure 1. Extra volume in the reactors is preferable to work as buffer in case of problems. If for example a reactor has a total volume of 30 liters it can have an operating volume of e.g. 10-12 liters. Figure 1 Picture of 4 reactors during aeration.
The length of the cycle depends on the planner and purpose of the reactors. A good idea when planning the length of the cycle is to take into consideration when experiments are made and when samples need to be taken. Cycles lasting 8 hours or less ensures that all stages in one cycle can be observed in one normal workday. If one cycle lasts 8 hours the SBRs operate 3 cycles per day. The SBR cycle has five stages; fill, react, settling, draw and idle. The chosen length of each stage is dependent on the designer. In Figure 2 an example of an 8 hour cycle is Figure 2 Example of an 8 hour cycle.
The cycles of the reactor are controlled by aeration, pumps and mixing. These are easy to control with a timer. It is however important to ensure that the timer is reliable and when using multiple timers, that they work properly and in the same time. The aeration can be arranged with an aeration stone and mixing, if needed, with a magnetic mixer. The aeration can be strong enough to fully mix the tanks so that no additional mixing is needed. Additional mixting is however needed if wanting to create for example anoxic conditions. An aeration stone and a timer are presented in Figure 3. Figure 3 Aeration stone and timer.
Pumps and tubing
The pumps and tubes should be easy to operate and maintain. Valves and the connections between tubes should be easy to disconnect. As the tubing easily start to accumulate biofilm and can even get clogged, the tubing should be changed regularly (each or every second week). The tubing can even flatten and wear out. This is important to monitor. The easiest way of doing this is to daily check the water level in the reactors. The tubes should also not be too long or loose so that they vibrate. Too much vibration of the tubing can affect the pumping of influent. The pumps should also be oiled regularly, especially when the tubing is changed. Examples of pumps and tubing are presented in Figure 4. The accuracy of the pumps and the influence the tubes have on the yields of the pumps are important to understand and monitor. The draw phase can be planned in a way that the accuracy of the pumps is not that important. This can be done by attaching the effluent tube to that height to where it is intended to remove water to. When the accurate amount of water has been removed, more water cannot be removed even if the pumps are still on. The feeding pumps need to be precise and their yield is important to control so that the accurate amount of influent water is fed to the reactors. Figure 4 Pumps and tubes.
Influent and effluent water
How much influent water is added and effluent removed, depends on the operational parameters. More than 1/3 of the reactors' operating volume is not recommended to be removed during a cycle. (New England Interstate Water Pollution Control Commission, 2005) A side from the organics load, when designing the amounts of water operated in the reactors, it is important to calculate how much effluent and influent water is needed and produced during a day and the weekends. As the reactors should operate without maintenance a couple of days, it is important to ensure that big enough buckets and tanks are available to hold the water. The effluent water can be led directly to the drain, but if the sludge would escape with the effluent it can be good to catch all effluents in separate tanks/buckets. Example of influent and effluent water tanks are presented in As the amount of influent water is equal to the amount of effluent water, these two should be considered together when designing the plant. The restricting parameter for influent water is the size of the influent water tank and how often it is made. The organics load in synthetically prepared wastewater decreases over time due to reactions in the wastewater tank. Because of this, synthetic wastewater is good to make as often as possible. But because the reactor should operate independently at least for a weekend and one extra day, wastewater can be prepared every 3 or 4 days, two times a week. The decreasing organics load should be taken into account when calculating the organics Figure 5 Picture of influent an effluent water tanks.
One of the most important parameters when designing the SBR is the sludge age/SRTaer. The sludge age is controlled by sludge wasting. Sludge wasting can either be manual or automatic. A manual sludge wasting arrangement is presented in Figure 6. Sludge can be removed only when the reactor is aerated or mixed thoroughly otherwise. Even if the theoretical sludge wasting can be calculated as sludge removed per day or cycle, it is not necessary to remove sludge every day. Sludge removal every other day can be sufficient enough for longer sludge ages (> 7 days). Figure 6 Picture of a manual sludge wasting arrangement (sludge wasted through a flexible hose).
Maintenance
The regular maintenance includes the following:  Preparing synthetic wastewater  Emptying effluent water tanks  Removing sludge  Keeping the reactor walls clean from sludge  Observing the yield of pumps  Checking the tubes and change them when necessary  Analyzing and following how the reactors are operating Analyses
The most important analyses to make on regular bases are MLSS and the organics analyses. The MLSS in the reactors tells how the sludge is adapting to the conditions in the reactors. If the MLSS sinks drastically after the start of the reactors, this can mean that the organics load is not sufficient. The organics load tells if the reactors are removing organics as planned. The pH is also important to monitor on an almost daily bases as this tells if the dose of chemicals that adds alkalinity is correct. Nitrification can also lower the pH in the process. Dissolved oxygen can also be measured regularly. The amount of oxygen in the reactors can be controlled. If however mixing with only aeration is wanted then the aeration needs to be strong all the time. Other analyses can be made depending on the purpose of the reactors. Possible problems
Denitrification and surface sludge
Sudden rises of organics loads can lead to problems in the reactors. If the tubing has stayed unchanged for long, they can have formed biofilm or other accumulation that then decrease the organics load that reach the reactors. When the tubing is then changed, this can lead to a larger organics load than the reactors are used to. In case the SBR is designed only to nitrify and denitrification starts and the reaction has a long time to take place, surface sludge can became a problem. A risk is that if the surface sludge forms before the draw stage of the cycle, the sludge is removed with the effluent water. As a conclusion, the tubing should be changed regularly to keep the actually fed organics load relatively constant. The react stage should also be long enough to ensure that organics are removed and the settling stage not so long that the anoxic conditions that make denitrification possible can form. The settling stage should however be long enough to ensure proper settling to occur. A picture of surface sludge is presented in Figure 7 Picture of surface sludge in a SBR (most likely caused by denitrification).
Settling of sludge
When choosing the operating parameters such as MLSS concentration and organics loads for the SBRs, the settling of sludge is good to take into consideration. If the settling is not good and the loads and MLSS concentrations are high, the settling of sludge can be a problem. Also excessive foaming in the reactors can be a problem and anti-foaming agents can be used. General tips
It is preferable to regularly check the reactors and observe the different stages of the cycles. Always when some change is made the following cycles are good to observe. Surprises and unexpected reactions to small changes can occur. Holidays and unexpected sickness are good to be prepared for. If the primary person who is responsible for the SBRs is sick, then someone else should be appointed to step in to ensure that the operation continues as usual. This means that more than one person needs to be familiar with the operation. References
New England Interstate Water Pollution Control Commission, 2005. Sequencing Batch Reactor Desing and Operational Considerations, Massachusetts

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