Calculation methods to perform mass balances of micropollutants in sewage treatment plants. application to pharmaceutical and personal care products (PPCPs)

Global trends in the research and development of medical/pharmaceutical wastewater treatment over the half-century

The COVID-19 pandemic has severely impacted public health and the worldwide economy. The overstretched operation of health systems around the world is accompanied by potential and ongoing environmental threats. At present, comprehensive scientific assessments of research on temporal changes in medical/pharmaceutical wastewater (MPWW), as well as estimations of researcher networks and scientific productivity are lacking. Therefore, we conducted a thorough literature study, using bibliometrics to reproduce research on medical wastewater over nearly half a century. Our primary goal is systematically to map the evolution of keyword clusters over time, and to obtain the structure and credibility of clusters. Our secondary objective was to measure research network performance (country, institution, and author) using CiteSpace and VOSviewer. We extracted 2306 papers published between 1981 and 2022. The co-cited reference network identified 16 clusters with well-structured networks (Q = 0.7716, S = 0.896). The main trends were as follows: 1) Early MPWW research prioritized sources of wastewater, and this cluster was considered to be the mainstream research frontier and direction, representing an important source and priority research area. 2) Mid-term research focused on characteristic contaminants and detection technologies. Particularly during 2000-2010, a period of rapid developments in global medical systems, pharmaceutical compounds (PhCs) in MPWW were recognized as a major threat to human health and the environment. 3) Recent research has focused on novel degradation technologies for PhC-containing MPWW, with high scores for research on biological methods. Wastewater-based epidemiology has emerged as being consistent with or predictive of the number of confirmed COVID-19 cases. Therefore, the application of MPWW in COVID-19 tracing will be of great interest to environmentalists. These results could guide the future direction of funding agencies and research groups.

Removal of Pharmaceuticals and Personal Care Products (PPCPs) by Free Radicals in Advanced Oxidation Processes

As emerging pollutants, pharmaceutical and personal care products (PPCPs) have received extensive attention due to their high detection frequency (with concentrations ranging from ng/L to μg/L) and potential risk to aqueous environments and human health. Advanced oxidation processes (AOPs) are effective techniques for the removal of PPCPs from water environments. In AOPs, different types of free radicals (HO·, SO₄·^-, O₂·^-, etc.) are generated to decompose PPCPs into non-toxic and small-molecule compounds, finally leading to the decomposition of PPCPs. This review systematically summarizes the features of various AOPs and the removal of PPCPs by different free radicals. The operation conditions and comprehensive performance of different types of free radicals are summarized, and the reaction mechanisms are further revealed. This review will provide a quick understanding of AOPs for later researchers.

Treatment of cosmetic industry wastewater by flotation with Moringa oleifera Lam. and aluminum sulfate and toxicity assessment of the treated wastewater

The production of personal hygiene and body products generates wastewater with a high load of surfactants, a high chemical oxygen demand (COD), and abundant oils and greases. Aluminum sulfate (AS) and two solutions of natural coagulant from Moringa oleifera Lam. seeds prepared with a 1M NaCl solution and 1.5M NaCl solution were used. Aluminum sulfate, Moringa oleifera Lam. in 1M NaCl, and Moringa oleifera Lam. in 1.5M NaCl solutions reduced turbidity at rates 94.48%, 98.07%, and 97.87%; reduced COD at rates 46.36%, 49.15%, and 42.7%; and reduced oil and grease at rates 98.72%, 78.65%, and 97.41%, respectively. Mutagenicity tests with guppies showed a lower toxicity of Moringa oleifera Lam. extract compared with aluminum sulfate. This work shows that Moringa oleifera Lam. extract has high potential for use as an alternative to aluminum sulfate; therefore, this study will contribute to proposals for the sustainable treatment of effluents from the cosmetic industry.

Removal of Emerging Contaminants from Wastewater Streams Using Membrane Bioreactors: A Review

Water is a very valuable natural resource. As the demand for water increases the presence of emerging contaminants in wastewater has become a growing concern. This is particularly true when one considers direct reuse of wastewater. Obtaining sufficient removal of emerging contaminants will require determining the level of removal for the various unit operations in the wastewater treatment process. Membrane bioreactors are attractive as they combine an activated sludge process with a membrane separation step. They are frequently used in a wastewater treatment process and can operate at higher solid loadings than conventional activated sludge processes. Determining the level of removal of emerging contaminants in the membrane bioreactor step is, therefore, of great interest. Removal of emerging contaminants could be by adsorption onto the biomass or membrane surface, biotransformation, size exclusion by the membrane, or volatilization. Given the fact that most emerging contaminants are low molecule weight non-volatile compounds, the latter two methods of removal are usually unimportant. However, biotransformation and adsorption onto the biomass are important mechanisms of removal. It will be important to determine if the microorganisms present at given treatment facility are able to remove ECs present in the wastewater.

Tonalide facilitates methane production from anaerobic digestion of waste activated sludge

Tonalide (AHTN), a typical polycyclic musk and an emerging pollutant, was found to be enriched in waste activated sludge (WAS). However, the research of its effect on WAS anaerobic digestion was seldom available. This research therefore investigated the effect of AHTN on WAS anaerobic digestion and the underlying mechanism through batch experiments using either real WAS or synthetic wastewaters as the digestion substrates. The results indicated that when the concentration of AHTN increased from 0 to 1000 mg/kg TSS in WAS, the methane production increased linearly from 125.0 ± 2.2 to 162.9 ± 1.6 mL/g VSS, while the AHTN concentration further increased to 2000 mg/kg TSS, the methane production decreased to 146.2 ± 2.1 mL/g VSS. At the same time AHTN can facilitate the utility of volatile fatty acid (VFAs), especially acetate and propionate. It was further found that the degradation efficiency of AHTN in anaerobic digestion was 42.7%. The mechanism investigation demonstrated that AHTN can promote the solubilization, homoacetogenesis, acetogenesis and methanogenesis processes, leading to an increase in methane production. Further analysis revealed that methanogenic archaea mainly belonged to the genera of Methanosaeta and Metheanobacterium, and their relative abundance increased accordingly with the addition of AHTN.

Chemical composition of extracellular polymeric substances and evolution of microbial community in activated sludge exposed to ibuprofen

Ibuprofen (IBU) containing wastewater with a concentration of 1-5 mg/L was treated in an activated sludge sequencing batch reactor (SBR), for 60 days, in order to investigate the overall performance of the SBR, the parameter variations during a typical cycle, the chemical composition and content of extracellular polymeric substances (EPS) and the evolution of microbial community. The average removal efficiencies of COD, NH₄⁺-N and TN were >85%, while >40% of the IBU was removed and the removal efficiencies of TP fluctuated around ~ 75%. The EPS content increased significantly with IBU addition (p < 0.01). Fulvic acid-like substances in the chemical composition of EPS increased during the stable operation phase. Proteobacteria associated with nitrogen removal was the dominant phylum, which can also resist IBU stress. For the denitrifying bacteria, the OTUs of both Rhodobacter and Pseudomonas increased from day 1-30 and reduced on day 60 (p < 0.01), which was opposite to the results observed for Rhodocyclaceae (phosphorus-accumulating bacteria). The OTUs of Acidovorax showed an increasing trend (p < 0.01), whereas the OTUs for Nitrospira (nitrite oxidizers) and Nitrosomonas (ammonia oxidizers) decreased significantly (p < 0.05).

Roles of ammonia-oxidizing bacteria in improving metabolism and cometabolism of trace organic chemicals in biological wastewater treatment processes: A review

While there has been a significant recent improvement in the removal of pollutants in natural and engineered systems, trace organic chemicals (TrOCs) are posing a major threat to aquatic environments and human health. There is a critical need for developing potential strategies that aim at enhancing metabolism and/or cometabolism of these compounds. Recently, knowledge regarding biodegradation of TrOCs by ammonia-oxidizing bacteria (AOB) has been widely developed. This review aims to delineate an up-to-date version of the ecophysiology of AOB and outline current knowledge related to biodegradation efficiencies of the frequently reported TrOCs by AOB. The paper also provides an insight into biodegradation pathways by AOB and transformation products of these compounds and makes recommendations for future research of AOB. In brief, nitrifying WWTFs (wastewater treatment facilities) were superior in degrading most TrOCs than non-nitrifying WWTFs due to cometabolic biodegradation by the AOB. To fully understand and/or enhance the cometabolic biodegradation of TrOCs by AOB, recent molecular research has focused on numerous crucial factors including availability of the compounds to AOB, presence of growth substrate (NH₄-N), redox potentials, microorganism diversity (AOB and heterotrophs), physicochemical properties and operational parameters of the WWTFs, molecular structure of target TrOCs and membrane-based technologies, may all significantly impact the cometabolic biodegradation of TrOCs. Still, further exploration is required to elucidate the mechanisms involved in biodegradation of TrOCs by AOB and the toxicity levels of formed products.

The influence of solid-liquid coefficient in the fate of pharmaceuticals and personal care products in aerobic wastewater treatment

Wastewater treatment plants (WWTPs) are considered to be a source of environmental contamination by micropollutants, especially from pharmaceuticals and personal care products (PCPs). The pathway of those compounds during sewage treatment has been investigated, but data from real-scale WWTPs is still missing (for example, the values of the solid-liquid coefficient (K_d) during treatment). This paper uses the K_d values for some pharmaceuticals and PCPs (fenofibrate, gemfibrozil, propranolol, metoprolol, salicylic acid, acetylsalicylic acid, ibuprofen, diclofenac, naproxen, fenoprofen, caffeine, triclosan, methylparaben, ethylparaben, propylparaben, butylparaben, and benzylparaben) to describe the micropollutants' behavior in the treatment process. In order to attain this data, an aerobic wastewater treatment plant located in Brazil was studied. Six samplings were carried out and a mass balance was performed, associating the concentrations of the micropollutants in the liquid phase with the solid phase (sludge and suspended solids). Of all the compounds analyzed, caffeine was the most biodegradable pollutant, as almost 98% of its mass was biodegraded. In contrast, triclosan had the highest load in sludge (median of 163.0 mg day^-1) and adsorbed in SS (median of 0.593 mg day^-1) at the output. Summing up, each micropollutant had a specific way to be removed during wastewater treatment.

Removal of antibiotic sulfamethoxazole by anoxic/anaerobic/oxic granular and suspended activated sludge processes

This study investigates the removal of the antibiotic sulfamethoxazole (SMX) in two sets of anoxic/anaerobic/oxic sequencing batch reactors inoculated with either suspended or granular activated sludge. Continuously, for three months, 2 μg/L SMX was spiked into the reactor feeds in a synthetic municipal wastewater with COD, total nitrogen (TN) and total phosphorous (TP) of 400, 43 and 7 mg/L, respectively. The presence of SMX had no significant impact on treatment performance of the suspended and granular biomass. After 12 h of hydraulic retention time, SMX removal efficiencies of 84 and 73% were obtained for the granular and suspended biomass, respectively. Mixing without aeration did not remove SMX, confirming the insignificance of SMX removal via sorption. The pseudo-first order SMX removal rate constants in the granular and suspended biomass were 2.25 ± 0.30 and 1.34 ± 0.39 L/gVSS·d, respectively. The results suggest that granules with advantages such as elevated biomass retention and greater biomass concentration could be effective for the removal of this class of antibiotics.

Occurrences and removal of pharmaceuticals and personal care products (PPCPs) in drinking water and water/sewage treatment plants: A review

In recent years, many of micropollutants have been widely detected because of continuous input of pharmaceuticals and personal care products (PPCPs) into the environment and newly developed state-of-the-art analytical methods. PPCP residues are frequently detected in drinking water sources, sewage treatment plants (STPs), and water treatment plants (WTPs) due to their universal consumption, low human metabolic capability, and improper disposal. When partially metabolized PPCPs are transferred into STPs, they elicit negative effects on biological treatment processes; therefore, conventional STPs are insufficient when it comes to PPCP removal. Furthermore, the excreted metabolites may become secondary pollutants and can be further modified in receiving water bodies. Several advanced treatment systems, including membrane filtration, granular activated carbon, and advanced oxidation processes, have been used for the effective removal of individual PPCPs. This review covers the occurrence patterns of PPCPs in water environments and the techniques adopted for their treatment in STP/WTP unit processes operating in various countries. The aim of this review is to provide a comprehensive summary of the removal and fate of PPCPs in different treatment facilities as well as the optimum methods for their elimination in STP and WTP systems.

Rethinking micropollutant removal assessment methods for wastewater treatment plants - how to get more robust data?

This paper covers the pitfalls, recommendations and a new methodology for assessing micropollutant removal efficiencies in wastewater treatment plants. The proposed calculation rules take into account the limit of quantification and the analytical and sampling uncertainty of measured concentrations. We identified six cases for which a removal efficiency value is reliable and four other cases where result is highly variable (uncertain) due to very low or unquantified concentrations in effluent or when the influent-effluent concentrations differential is below the measurement uncertainty. The influence of the proposed calculation rules on removal efficiency values was scrutinized using actual results from a research project. The paper arrives at detailed recommendations for limiting the impact of other sources of uncertainty during sampling (sampling strategy, cleaning and field blank), chemical analyses (suspended solids and sludge) and data processing according to the targeted objectives.

Fate and mass balance of contaminants of emerging concern during wastewater treatment determined using the fractionated approach

Contaminants of emerging concern (CECs) are often poorly removed from wastewater using conventional treatment technologies and there is limited understanding of their fate during treatment. Inappropriate sampling strategies lead to inaccuracies in estimating removals of CECs. In this study, we used the "fractionated approach" that accounts for the residence time distribution (RTD) in treatment units to investigate the fate of 26 target CECs in a municipal wastewater treatment plant (WWTP) that includes primary, secondary and tertiary treatment steps. Prior hydraulic calibration of each treatment unit was performed. Wastewater and sludge samples were collected at different locations along the treatment train and the concentrations of target CECs were measured by liquid chromatography mass spectrometry. The most substantial aqueous removal occurred during activated sludge treatment (up to 99%). Removals were <50% in the primary clarifier and tertiary rotating biological contactors (RBCs) and up to 70% by sand filtration. Mass balance calculations demonstrated that (bio)degradation accounted for up to 50% of the removal in the primary clarifier and 100% in activated sludge. Removal by sorption to primary and secondary sludge was minimal for most CECs. Analysis of the selected metabolites demonstrated that negative removals obtained could be explained by transformations between the parent compound and their metabolites. This study contributes to the growing literature by applying the fractionated approach to calculate removal of different types of CECs across each wastewater treatment step. An additional level of understanding of the fate of CECs was provided by mass balance calculations in primary and secondary treatments.

Status of hormones and painkillers in wastewater effluents across several European states-considerations for the EU watch list concerning estradiols and diclofenac

Present technologies for wastewater treatment do not sufficiently address the increasing pollution situation of receiving water bodies, especially with the growing use of personal care products and pharmaceuticals (PPCP) in the private household and health sector. The relevance of addressing this problem of organic pollutants was taken into account by the Directive 2013/39/EU that introduced (i) the quality evaluation of aquatic compartments, (ii) the polluter pays principle, (iii) the need for innovative and affordable wastewater treatment technologies, and (iv) the identification of pollution causes including a list of principal compounds to be monitored. In addition, a watch list of 10 other substances was recently defined by Decision 2015/495 on March 20, 2015. This list contains, among several recalcitrant chemicals, the painkiller diclofenac and the hormones 17β-estradiol and 17α-ethinylestradiol. Although some modern approaches for their removal exist, such as advanced oxidation processes (AOPs), retrofitting most wastewater treatment plants with AOPs will not be acceptable as consistent investment at reasonable operational cost. Additionally, by-product and transformation product formation has to be considered. The same is true for membrane-based technologies (nanofiltration, reversed osmosis) despite of the incredible progress that has been made during recent years, because these systems lead to higher operation costs (mainly due to higher energy consumption) so that the majority of communities will not easily accept them. Advanced technologies in wastewater treatment like membrane bioreactors (MBR) that integrate biological degradation of organic matter with membrane filtration have proven a more complete elimination of emerging pollutants in a rather cost- and labor-intensive technology. Still, most of the presently applied methods are incapable of removing critical compounds completely. In this opinion paper, the state of the art of European WWTPs is reflected, and capacities of single methods are described. Furthermore, the need for analytical standards, risk assessment, and economic planning is stressed. The survey results in the conclusion that combinations of different conventional and advanced technologies including biological and plant-based strategies seem to be most promising to solve the burning problem of polluting our environment with hazardous emerging xenobiotics.

The fate of mercury in municipal wastewater treatment plants in China: Significance and implications for environmental cycling

Municipal wastewater treatment plants (WWTPs) play an important role in controlling pollutant discharges to surface waters. Previous studies suggested that the removal of mercury (Hg) by WWTPs was strongly correlated with solid removal. However, conclusions regarding possible transformations of Hg species within WWTPs were not consistent across those studies. We characterized total Hg (THg) and methylmercury (MeHg) concentrations and loads in a WWTP located in Jiaozuo, China, to further understand Hg fate and transformations in WWTPs. THg and MeHg were primarily associated with wastewater solids, and removal of both were greater than 90%; concentrations in the sewage were (2.0±2.7)×10(3)ng/L and 7.5±5.8ng/L, respectively. A mass balance calculation revealed that 80% of the THg input to the WWTP ended up in the sewage sludge (SS), while more than 70% of the influent MeHg mass was degraded, indicating WWTPs are an important sink for sewage-borne Hg. THg and MeHg concentrations in SS were (3.9±1.4)×10(3)ng/g and 6.3±2.3ng/g, respectively, suggesting SS could be a significant source of THg and MeHg to the environment if not handled properly. The significance of sewage and SS in the biogeochemical cycling of THg and MeHg in China is discussed.

A UASB reactor coupled to a hybrid aerobic MBR as innovative plant configuration to enhance the removal of organic micropollutants

An innovative plant configuration based in an UASB reactor coupled to a hybrid aerobic membrane bioreactor designed for sustainable treatment of municipal wastewater at ambient temperatures and low hydraulic retention time was studied in terms of organic micropollutants (OMPs) removal. OMPs removal mechanisms, as well as the potential influence of biomass activity and physical conformation were assessed. Throughout all periods of operation (150 days) high organic matter removals were maintained (>95%) and, regarding OMPs removal, this innovative system has shown to be more efficient than conventional technologies for those OMPs which are prone to be biotransformed under anaerobic conditions. For instance, sulfamethoxazole and trimethoprim have both shown to be biodegradable under anaerobic conditions with similar efficiencies (removal efficiencies above 84%). OMPs main removal mechanism was found to be biotransformation, except in the case of musk fragrances which showed medium sorption onto sludge. OMPs removal was strongly dependent on the efficiency of the primary metabolism (organic matter degradation and nitrification) and the type of biomass.

Pharmaceuticals and personal care products in untreated and treated sewage sludge: Occurrence and environmental risk in the case of application on soil - A critical review

This review is based on 59 papers published between 2002 and 2015, referring to about 450 treatment trains providing data regarding sludge concentrations for 169 compounds, specifically 152 pharmaceuticals and 17 personal care products, grouped into 28 different classes. The rationale of the study is to provide data to evaluate the environmental risk posed by the spreading of treated sludge in agriculture. Following discussion of the legislative scenario governing the final disposal of treated sludge in European countries and the USA, the study provides a snapshot of the occurrence of selected compounds in primary, secondary, mixed, digested, conditioned, composted and dried sludge originating in municipal wastewater treatment plants fed mainly with urban wastewater as well as in sludge-amended soil. Not only are measured values reported, but also predicted concentrations based on Kd values are reported. It emerges that in secondary sludge, the highest concentrations were found for fragrances, antiseptics and antibiotics and an attenuation in their concentrations occurs during treatment, in particular anaerobic digestion and composting. An in-depth literature survey of the (measured and predicted) Kd values for the different compounds and treated sludge are reported and an analysis of the influence of pH, redox conditions, sludge type was carried out. The data regarding measured and predicted concentrations of selected compounds in sludge-amended soil is then analyzed. Finally an environmental risk assessment posed by their occurrence in soil in the case of land application of sludge is examined, and the results obtained by different authors are compared. The most critical compounds found in the sludge-amended soil are estradiol, ciprofloxacin, ofloxacin, tetracycline, caffeine, triclosan and triclocarban. The study concludes with a focus on the main issues that should be further investigated in order to refine the environmental risk assessment.

Fate of anthropogenic cyclic volatile methylsiloxanes in a wastewater treatment plant

The fate of cyclic volatile methylsiloxanes (cVMS) - octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), and dodecamethylcyclohexasiloxane (D6) - was evaluated in a typical secondary activated sludge wastewater treatment plant (WWTP). Water samples (influent, primary effluent, and final effluent) and sludge (primary sludge and waste activated sludge) samples were collected at overnight low, morning high, afternoon low, and evening high flows. Concentrations of cVMS in influents fluctuated with the influent flows, ranging from 0.166 to 1.13 μg L(-1), 3.47-19.3 μg L(-1), and 0.446-3.87 μg L(-1) for D4, D5, and D6, respectively. Mass balance analysis of cVMS showed the average mass of D4, D5, and D6 entering and exiting the plant in influent and effluent, respectively, were 109 g d(-1), 2050 g d(-1), 280 g d(-1), and 1.41 g d(-1), 27.0 g d(-1), 1.90 g d(-1). The total removal efficiency of cVMS was >96%. To elucidate their detailed removal mechanisms, Mackay's fugacity-based treatment plant model was used to simulate the fate of cVMS through the WWTP. Due to the unusual combination of high hydrophobicity and volatility of cVMS, volatilization in the aeration tank and adsorption to sludge were the two main pathways of cVMS removal from water in this WWTP based on the experimental and modeled results. The morning and evening high influent mass flows contributed almost equally at approximately 40% of the total daily cVMS mass, with D5 accounting for the majority of this daily loading.

Removal of PPCPs from the sludge supernatant in a one stage nitritation/anammox process

Pharmaceutical and personal care products (PPCPs) are extensively used and can therefore find their way into surface, groundwater and municipal and industrial effluents. In this work, the occurrence, fate and removal mechanisms of 19 selected PPCPs was investigated in an 'ELiminación Autótrofa de Nitrógeno' (ELAN) reactor of 200 L. In this configuration, ammonium oxidation to nitrite and the anoxic ammonium oxidation (anammox)processes occur simultaneously in a single-stage reactor under oxygen limited conditions. The ELAN process achieved high removal (>80%) of the studied hormones, naproxen, ibuprofen, bisphenol A and celestolide, while it was not effective in the removal of carbamazepine (<7%), diazepam (<7%) and fluoxetine (<30%). Biodegradation was the dominant removal mechanism, while sorption was only observed for musk fragrances, fluoxetine and triclosan. The sorption was strongly dependent on the granule size, with smaller granules facilitating the sorption of the target compounds. Increased hydraulic retention time enhanced the intramolecular diffusion of the PPCPs into the granules, and thus increased the solid phase concentration. The increase of nitritation rate favored the removal of ibuprofen, bisphenol A and triclosan, while the removal of erythromycin was strongly correlated to the anammox reaction rate.

Occurrence and removal of benzotriazole ultraviolet stabilizers in a wastewater treatment plant in China

Benzotriazole ultraviolet stabilizers (BZT-UVs) have previously been found in sludge from wastewater treatment plants (WWTPs), which might be potential sources of BZT-UVs to the surrounding environment. In this work, the occurrence and fate of seven emerging 2-hydroxyphenyl substituted BZT-UVs were investigated in a Chinese WWTP. This group of hydrophobic BZT-UVs possess log Kow values ranging from 4.31 to 7.67 which could be associated with their fate in WWTPs. Field samples including 24 h flow composites of influent, effluent and grab sludge samples from different treatment processes were collected and analyzed. Concentrations of BZT-UVs dissolved in aqueous-phases were in the range of 4.88±1.35 (UV-234) to 34.5±12.4 ng L(-1) (UV-P) in the primary influent, while only UV-P and UV-328 were detected in the final effluent at concentrations of 10.5±6.59 and 2.74±1.73 ng L(-1), respectively. Considering the amount of target BZT-UVs adsorbed to total suspended solids (TSS), the daily mass flux in the primary influent of the WWTP ranged from 22.3 g day(-1) (UV-P, 7.99%) to 74.0 g day(-1) (UV-234, 26.5%). Total removal efficiency of the integrated treatment process ranged from 89.7% for UV-P to 99.7% for UV-234 suggesting nearly complete removal. Organic solid sedimentation in primary and secondary clarifiers was the dominant elimination route for BZT-UV analogues, which constituted 96.3% of the total removal efficiency. Advanced treatment (using ultraviolet disinfection) in this plant might further contribute to the high removal efficiencies (ranging from 19.6% to 77.3%).

Removal and fate of endocrine disruptors chemicals under lab-scale postreatment stage. Removal assessment using light, oxygen and microalgae

The aim of this study was to assess the effect of light, oxygen and microalgae on micropollutants removal. The studied micropollutants were 4-(1,1,3,3-tetramethylbutyl)phenol (OP), technical-nonylphenol (t-NP), 4-n-nonylphenol (4-NP), Bisphenol-A (BPA). In order to study the effect of the three variables on the micropollutants removal, a factorial design was developed. The experiments were carried out in four batch reactors which treated the effluent of an anaerobic membrane bioreactor. The gas chromatography mass spectrometry was used for the measurement of the micropollutants. The results showed that light, oxygen and microalgae affected differently to the degradation ratios of each micropollutant. The results showed that under aerated conditions removal ratios higher than 91% were achieved, whereas for non-aerated conditions the removal ratios were between 50% and 80%, except for 4-NP which achieved removal ratios close to 100%. Besides, mass balance showed that the degradation processes were more important than the sorption processes.

Characterization and biodegradation kinetics of a new cold-adapted carbamazepine-degrading bacterium, Pseudomonas sp. CBZ-4

Carbamazepine is frequently detected in waters and hardly eliminated during conventional wastewater treatment processes due to its complicated chemical structure and resistance to biodegradation. A carbamazepine-degrading bacterium named CBZ-4 was isolated at a low temperature (10 degreeC) from activated sludge in a municipal wastewater treatment plant. Strain CBZ-4, which can use carbamazepine as its sole source of carbon and energy, was identified as Pseudomonas sp. by the 16S rRNA gene sequence. The composition and percentage of fatty acids, which can reveal the cold-adaptation mechanism of strain CBZ-4, were determined. Strain CBZ-4 can effectively degrade carbamazepine at optimal conditions: pH 7.0, 10 degreeC, 150 r/min rotation speed, and 13% inoculation volume. The average removal rate of carbamazepine was 46.6% after 144 hr of incubation. The biodegradation kinetics of carbamazepine by CBZ-4 was fitted via the Monod model. Vmax and Ks were found to be 0.0094 hr-1 and 32.5 mg/L, respectively.

Insight into metabolic and cometabolic activities of autotrophic and heterotrophic microorganisms in the biodegradation of emerging trace organic contaminants

Many efforts have been made to understand the biodegradation of emerging trace organic contaminants (EOCs) in the natural and engineered systems. This review summarizes the current knowledge on the biodegradation of EOCs while having in-depth discussion on metabolism and cometabolism of EOCs. Biodegradation of EOCs is mainly attributed to cometabolic activities of both heterotrophic and autotrophic microorganisms. Metabolism of EOCs can only be observed by heterotrophic microbes. Autotrophic ammonia oxidizing bacteria (AOB) and ammonia oxidizing archaeal (AOA) cometabolize a variety of EOCs via the non-specific enzymes, such as ammonia monooxygenase (AMO). Higher biodegradation of EOCs is often noted under nitrification at high ammonia loading rate. The presence of a growth substrate promotes cometabolic biodegradation of EOCs. Potential strategies for enhancing the biodegradation of EOCs were also proposed in this review.

Aerobic biodegradation of the sulfonamide antibiotic sulfamethoxazole by activated sludge applied as co-substrate and sole carbon and nitrogen source

Potential aerobic biodegradation mechanisms of the widely used polar, low-adsorptive sulfonamide antibiotic sulfamethoxazole (SMX) were investigated in activated sludge at bench scale. The study focused on (i) SMX co-metabolism with acetate and ammonium nitrate and (ii) SMX utilization when present as the sole carbon and nitrogen source. With SMX adsorption being negligible, elimination was primarily based on biodegradation. Activated sludge was able to utilize SMX both as a carbon and/or nitrogen source. SMX biodegradation was enhanced when a readily degradable energy supply (acetate) was provided which fostered metabolic activity. Moreover, it was raised under nitrogen deficiency conditions. The mass balance for dissolved organic carbon showed an incomplete SMX mineralization with two scenarios: (i) with SMX as a co-substrate, 3-amino-5-methyl-isoxazole represented the main stable metabolite and (ii) SMX as sole carbon and nitrogen source possibly yielded hydroxyl-N-(5-methyl-1,2-oxazole-3-yl)benzene-1-sulfonamide as a further metabolite.

Sludge Retention Time as a Suitable Operational Parameter to Remove Both Estrogen and Nutrients in an Anaerobic-Anoxic-Aerobic Activated Sludge System

Estrogen in wastewater are responsible for a significant part of the endocrine-disrupting effects observed in the aquatic environment. The effect of sludge retention time (SRT) on the removal and fate of 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) in an anaerobic-anoxic-oxic activated sludge system designed for nutrient removal was investigated by laboratory-scale experiments using synthetic wastewater. With a hydraulic retention time of 8 h, when SRT ranged 10-25 days, E2 was almost completely removed from water, and EE2 removal efficiency was 65%-81%. Both estrogens were easily sorbed onto activated sludge. Distribution coefficients (K_d) of estrogens on anaerobic sludge were greater than those on anoxic and aerobic sludges. Mass balance calculation indicated that 99% of influent E2 was degraded by the activated sludge process, and 1% remained in excess sludge; of influent EE2, 62.0%-80.1% was biodegraded; 18.9%-34.7% was released in effluent; and 0.88%-3.31% remained in excess sludge. Optimal SRT was 20 days for both estrogen and nutrient removal. E2 was almost completely degraded, and EE2 was only partly degraded in the activated sludge process. Residual estrogen on excess sludge must be considered in the sludge treatment and disposal processes. The originality of the work is that removal of nutrients and estrogens were linked, and optimal SRT for both estrogen and nutrient removal in an enhanced biological phosphorus removal system was determined. This has an important implication for the design and operation of full-scale wastewater treatment plants.

Acidic pharmaceuticals in domestic wastewater and receiving water from hyper-urbanization city of China (Shanghai): environmental release and ecological risk

The occurrence, behavior, and release of five acidic pharmaceuticals, including ibuprofen (IBP), naproxen (NPX), ketoprofen (KEP), diclofenac (DFC), and clofibric acid (CA), have been investigated along the different units in a tertiary-level domestic wastewater treatment plant (WWTP) in hyper-urbanization city of China (Shanghai). IBP was the most abundant chemicals among the measured in raw wastewater. The loads of the acidic pharmaceuticals in the WWTP influent ranged from 7.5 to 414 mg/day/1,000 inh, which were lower than those reported in the developed countries suggesting a less per capita consumption of pharmaceuticals in Shanghai. IBP obtained by highest removal (87 %); NPX and KEP were also significantly removed (69-76 %). However, DFC and CA were only moderately removed by 37-53 %, respectively. Biodegradation seemed to play a key role in the elimination of the studied pharmaceuticals except for DFC and CA. An annual release of acidic pharmaceuticals was estimated at 1,499 and 61.7 kg/year through wastewater and sludge, respectively, from Shanghai. Highest pharmaceuticals concentrations were detected in the effluent discharge point of the WWTP, indicating that WWTP effluent is the main source of the acidic pharmaceuticals to its receiving river. Preliminary results indicated that only DFC in river had a high risk to aquatic organisms. Nevertheless, the joint toxicity effects of these chemicals are needed to further investigate.

Influence of nitrifying conditions on the biodegradation and sorption of emerging micropollutants

High biodegradation efficiencies of different emerging micropollutants were obtained with nitrifying activated sludge (NAS) working at high nitrogen loading rates (NLR), that boosted the development of biomass with high nitrifying activities (>1 g N-NH(4)(+)/g VSS d). Come-tabolic biodegradation seemed to be responsible for the removal of most compounds due to the action of the ammonium monooxygenase enzyme. NAS showed a different affinity for each compound, probably due to steric hindrance, activation energy limitations or the presence of specific functional groups. Increasing loading rates of micropollutants were removed at shorter hydraulic retention times, although the biodegradation efficiencies of compounds with slow/intermediate kinetics, such as fluoxetine, erythromycin, roxithromycin and trimethoprim, diminished due to kinetic and/or stoichiometric limitations. Solids retention time, always above the minimum to avoid the washout of nitrifiers, did not enhance the biodegradation of any of the selected compounds, with the exception of diclofenac. Regarding sorption, the solid-liquid distribution coefficients (K(d)) obtained in NAS were very similar to those found in conventional activated sludge by other authors. No correlation between K(d) values and any of the operational parameters was found for the selected substances.

Assessing the removal of pharmaceuticals and personal care products in a full-scale activated sludge plant

PURPOSE

This study aimed to investigate the removal mechanisms of pharmaceutical active compounds (PhACs) and musks in a wastewater treatment plant (WWTP). Biological removal and adsorption in the activated sludge tank as well as the effect of UV radiation used for disinfection purposes were considered when performing a mass balance on the WWTP throughout a 2-week sampling campaign.

METHODS

Solid-phase extraction (SPE) was carried out to analyse the PhACs in the influent and effluent samples. Ultrasonic solvent extraction was used before SPE for PhACs analysis in sludge samples. PhAC extracts were analysed by LC-MS. Solid-phase microextraction of liquid and sludge samples was used for the analysis of musks, which were detected by GC-MS. The fluxes of the most abundant compounds (13 PhACs and 5 musks) out of 79 compounds studied were used to perform the mass balance on the WWTP.

RESULTS

Results show that incomplete removal of diclofenac, the compound that was found in the highest abundance, was observed via biodegradation and adsorption, and that UV photolysis was the main removal mechanism for this compound. The effect of adsorption to the secondary sludge was often negligible for the PhACs, with the exceptions of diclofenac, etofenamate, hydroxyzine and indapamide. However, the musks showed a high level of adsorption to the sludge. UV radiation had an important role in reducing the concentration of some of the target compounds (e.g. diclofenac, ibuprofen, clorazepate, indapamide, enalapril and atenolol) not removed in the activated sludge tank.

CONCLUSIONS

The main removal mechanism of PhACs and musks studied in the WWTP was most often biological (45%), followed by adsorption (33%) and by UV radiation (22%). In the majority of the cases, the WWTP achieved >75% removal of the most detected PhACs and musks, with the exception of diclofenac.

Methodology to account for uncertainties and tradeoffs in pharmaceutical environmental hazard assessment

Many pharmaceutical products find their way into receiving waters, giving rise to concerns regarding their environmental impact. A procedure was proposed that enables ranking of the hazard to aquatic species and human health due to such products. In the procedure, hazard assessment is based on five of the pharmaceutical product's individual physico-chemical properties. These properties are aggregated using the weighted Euclidian distance as the utility function. The weights and physico-chemical properties are considered as random variables. Physico-chemical property uncertainty criteria are obtained from a literature review. Weight uncertainty is based on a hazard ranking from a panel of experts, the histogram of which is converted into a continuous probability density function using statistical Kernel smoothing technique. The hazard-ranking procedure was applied to a list of common pharmaceuticals used in Switzerland. The procedure is target-specific. Two rankings were presented: One giving priority to environmental protection and the other to human health. For most substances, the hazard rank depends on the target. For the Swiss case study, the ranking procedure led to the conclusion that the hormones ethinylestradiol and testosterone, along with the antibiotic erythromycin A, should be in all cases included in risk-assessment methodologies, environmental concentration estimates and regular measurement campaigns. The methodology proposed is flexible and can be extrapolated to other substances and groups of experts.

Fate of selected estrogens in two laboratory scale sequencing batch reactors fed with different organic carbon sources under varying solids retention times

This study compared the performances of two laboratory-scale sequencing batch reactors to remove 17β-estradiol and 17α-ethinyl estradiol. Both SBRs were operated to achieve organic carbon oxidation and nitrification. However, the overall bacterial population in both SBRs was targeted to be different by feeding the SBRs with peptone and glucose. Furthermore, the reactors were also run at different solid retention times (SRTs) to evaluate the effect of SRT on estrogen removal. The more diverse heterotrophic and ammonia oxidizing bacterial community in the peptone fed SBR1 had superior estrogen removal than the glucose fed SBR 2 which enriched less diverse community, particularly for 17α-ethinyl estradiol. Under a solids retention time (SRT) of 40days, the total 17β-estradiol mass was 30% of the amount under the SRT of 20days, and the total 17α-ethinyl estradiol mass was likewise 40% of the amount under the shorter SRT.

Fate of sulfonamide antibiotics in contact with activated sludge--sorption and biodegradation

The sorption and biodegradation of three sulfonamide antibiotics, namely sulfamethoxazole (SMX), sulfadimethoxine (SDM), and sulfamonomethoxine (SMM), in an activated sludge system were investigated. Experiments were carried out by contacting 100 μg/L of each sulfonamide compound individually with 2.56 g/L of MLSS at 25±0.5 °C, pH 7.0, and dissolved oxygen of 3.0±0.1 mg/L in a batch reactor over different periods of 2 d and 14 d. All sulfonamides were removed completely over 11-13 d. Sorptive equilibrium was established well within the first few hours, followed by a lag period of 1-3 days before biodegradation was to deplete the antibiotic compounds linearly in the ensuing 10 days. Apparent zeroth-order rate constants were obtained by regression analysis of measured aqueous concentration vs. time profiles to a kinetic model accounting for sorption and biodegradation; they were 8.1, 7.9, and 7.7 μg/L/d for SDM, SMX, and SMM, respectively, at activated sludge concentration of 2.56 g/L. The measured kinetics implied that with typical hydraulic retention time (e.g. 6 h) provided by WWTP the removal of sulfonamide compounds from the wastewater during the activated sludge process would approximate 2 μg/L.

Continental scale inverse modeling of common organic water contaminants in European rivers

The paper presents an analysis of measured riverine concentrations of 16 common organic water contaminants. From observed concentrations we back-calculate emissions and chemical half lives through a simple inverse model. The analysis does not allow identifying a single half life/emission factor combination, but a set of combinations which are Pareto-optimal (or "non-dominated"). The approach is shown to provide a rational basis for the screening of chemicals in rivers: with reference to the 16 chemicals considered here, estimated emission factors and half lives are consistent with the ones reported in other studies. For more precise estimates, prior knowledge about either emission factors or half lives is necessary. For the considered chemicals, loads to European seas can be subsequently estimated with an uncertainty usually within a factor of 2. The approach can be proposed for the inventorying of catchment-specific chemical pollutant emissions required for European environmental policies.

The air-water exchange of polychlorinated biphenyls and polybrominated diphenyl ethers at an urban lake, a receipt water body for the effluent from a municipal sewage treatment plant

The effluents and sludge from municipal sewage treatment plants (MSTPs) are considered as potential sources of many contaminants to the ambient environments. In the present work, the air-water exchange of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) was studied using passive air samplers at an urban lake, which receives the effluents from a MSTP in Beijing, China. The concentrations of PCBs and PBDEs in atmosphere were in the range 15.5-108 ng sample(-1) and 2.37-27.8 ng sample(-1), respectively, during the sampling period (August, 2007-July, 2008). The predominant PCBs and PBDEs were lowly halogenated congeners. The calculation for the exchange fluxes of PCBs and PBDEs using fugacity model showed that, the net exchange fluxes in different seasons were closely related to the halogen number of different congeners. Except for CBs-28 and 52, the net exchange fluxes was mainly directed from air to water for most of predominant congeners, which implied that the lower chlorinated CBs were dominated by volatilization process rather than the dry/wet depositions and diffusion between air-water interface, additionally, for heavy congeners, the dry/wet deposition process was an important source of PCBs and PBDEs in this lake.

Occurrence and removal of pharmaceuticals and personal care products (PPCPs) in an advanced wastewater reclamation plant

The occurrence of nineteen pharmaceutically active compounds and personal care products was followed monthly for 12 months after various stages of treatment in an advanced wastewater reclamation plant in Gwinnett County, GA, U.S.A. Twenty-four hour composite samples were collected after primary clarification, activated sludge biological treatment, membrane filtration, granular media filtration, granular activated carbon (GAC) adsorption, and ozonation in the wastewater reclamation plant. Compounds were identified and quantified using high performance liquid chromatography/tandem mass spectrometry (LC-MS/MS) and gas chromatography/mass spectrometry (GC-MS) after solid-phase extraction. Standard addition methods were employed to compensate for matrix effects. Sixteen of the targeted compounds were detected in the primary effluent; sulfadimethoxine, doxycycline, and iopromide were not found. Caffeine and acetaminophen were found at the highest concentrations (∼10(5) ng/L), followed by ibuprofen (∼10(4) ng/L), sulfamethoxazole and DEET (∼10(3) ng/L). Most of the other compounds were found at concentrations on the order of hundreds of ng/L. After activated sludge treatment and membrane filtration, the concentrations of caffeine, acetaminophen, ibuprofen, DEET, tetracycline, and 17α-ethynylestradiol (EE2) had decreased by more than 90%. Erythromycin and carbamazepine, which were resistant to biological treatment, were eliminated by 74 and 88%, on average, by GAC. Primidone, DEET, and caffeine were not amenable to adsorption by GAC. Ozonation oxidized most of the remaining compounds by >60%, except for primidone and DEET. Of the initial 16 compounds identified in the primary effluent, only sulfamethoxazole, primidone, caffeine and DEET were frequently detected in the final effluent, but at concentrations on the order of 10-100 ng/L. Removal of the different agents by the various treatment processes was related to the physical-chemical properties of the compounds.

Removal of steroid estrogens in carbonaceous and nitrifying activated sludge processes

A carbonaceous (heterotrophic) activated sludge process (ASP), nitrifying ASP and a nitrifying/denitrifying ASP have been studied to examine the role of process type in steroid estrogen removal. Biodegradation efficiencies for total steroid estrogens (Sigma(EST)) of 80 and 91% were recorded for the nitrifying/denitrifying ASP and nitrifying ASP respectively. Total estrogen biodegradation (Sigma(EST)) was only 51% at the carbonaceous ASP, however, the extent of biodegradation in the absence of nitrification clearly indicates the important role of heterotrophs in steroid estrogen removal. The low removal efficiency did not correlate with biomass activity for which the ASP(carbonaceous) recorded 80 microg kg(-1) biomass d(-1) compared to 61 and 15 microg kg(-1) biomass d(-1) at the ASP(nitrifying) and ASP(nitrifying/denitrifying) respectively. This finding was explained by a moderate correlation (r(2)=0.55) between total estrogen loading (Sigma(EST) mgm(-3)d(-1)) and biomass activity (microg Sigma(EST) degraded kg(-1) d(-1)) and has established the impact of loading on steroid estrogen removal at full-scale. At higher solids retention time (SRT), steroid estrogen biodegradation of>80% was observed, as has previously been reported. It is postulated that hydraulic retention time (HRT) is as important as SRT as this governs both reaction time and loading. This observation is based on the high specific estrogen activity determined at the ASP(carbonaceous) plant, the significance of estrogen loading and the positive linear correlation between SRT and HRT.

Sampling for pharmaceuticals and personal care products (PPCPs) and illicit drugs in wastewater systems: are your conclusions valid? A critical review

The analysis of 87 peer-reviewed journal articles reveals that sampling for pharmaceuticals and personal care products (PPCPs) and illicit drugs in sewers and sewage treatment plant influents is mostly carried out according to existing tradition or standard laboratory protocols. Less than 5% of all studies explicitly consider internationally acknowledged guidelines or methods for the experimental design of monitoring campaigns. In the absence of a proper analysis of the system under investigation, the importance of short-term pollutant variations was typically not addressed. Therefore, due to relatively long sampling intervals, potentially inadequate sampling modes, or insufficient documentation, it remains unclear for the majority of reviewed studies whether observed variations can be attributed to "real" variations or if they simply reflect sampling artifacts. Based on results from previous and current work, the present paper demonstrates that sampling errors can lead to overinterpretation of measured data and ultimately, wrong conclusions. Depending on catchment size, sewer type, sampling setup, substance of interest, and accuracy of analytical method, avoidable sampling artifacts can range from "not significant" to "100% or more" for different compounds even within the same study. However, in most situations sampling errors can be reduced greatly, and sampling biases can be eliminated completely, by choosing an appropriate sampling mode and frequency. This is crucial, because proper sampling will help to maximize the value of measured data for the experimental assessment of the fate of PPCPs as well as for the formulation and validation of mathematical models. The trend from reporting presence or absence of a compound in "clean" water samples toward the quantification of PPCPs in raw wastewater requires not only sophisticated analytical methods but also adapted sampling methods. With increasing accuracy of chemical analyses, inappropriate sampling increasingly represents the major source of inaccuracy. A condensed step-by-step Sampling Guide is proposed as a starting point for future studies.

Fate and removal of estrogens in municipal wastewater

Natural and synthetic estrogens are some of the most potent endocrine disrupting compounds found in municipal wastewater. Much research has been conducted on the source and fate of estrogens in wastewater treatment plants. Sorption and biodegradation are the primary removal mechanisms for estrogens in activated sludge systems, which are widely used biological treatment techniques for municipal wastewater treatment. However, when removal of estrogens in a wastewater treatment plant is incomplete, these compounds enter the environment through wastewater discharges or waste activated sludge at concentrations that can cause endocrine-reproductive system alterations in birds, reptiles and mammals. Therefore, studies have also focused on potential advanced treatment technologies with the aim of removing the compounds before discharging wastewater effluent or disposing waste sludge. This review discusses the physiological effects of these estrogens and the degree of problems estrogens pose as they enter the wastewater stream. Thereafter, this review also analyzes their fate in wastewater treatment systems and how they may reach drinking water sources. Furthermore, this review includes a discussion on various treatment technologies being investigated and future research trends for this pressing environmental issue.

Removal of antibiotics and non-steroidal anti-inflammatory drugs by extended sludge age biological process

Removal of four antibiotics (sulfamethoxazole, sulfadimethoxine, sulfamethazine and trimethoprim) and four non-steroidal anti-inflammatory drugs (acetaminophen, ibuprofen, ketoprofen and naproxen) using extended sludge age biological process was investigated. The sludge age of the biological system was greater than 200d. Hydraulic retention time of 12h was maintained throughout the experiment. The extended sludge age biological process is able to treat pharmaceuticals with good and steady removal efficiencies: 64-93% removal for antibiotics over 1-5microgL(-1) influent concentrations and 94% to complete removal for acetaminophen and ibuprofen with a wide range of influent concentrations 1-100microgL(-1). For ketoprofen and naproxen the removal efficiencies are 79-96% over a range of 1-15microgL(-1) influent concentrations. The removal efficiency decreases with increasing initial concentrations for all target compounds except for ibuprofen. This indicates that the initial influent concentration is an important parameter for the studies of fate of pharmaceuticals. The amount of bio-mass and size of the reactor required to achieve good and steady removal efficiencies for known influent pharmaceutical concentrations are also suggested in this study.

Influence of operating parameters on the biodegradation of steroid estrogens and nonylphenolic compounds during biological wastewater treatment processes

This study investigated operational factors influencing the removal of steroid estrogens and nonylphenolic compounds in two sewage treatment works, one a nitrifying/denitrifying activated sludge plant and the other a nitrifying/denitrifying activated sludge plant with phosphorus removal. Removal efficiencies of >90% for steroid estrogens and for longer chain nonylphenol ethoxylates (NP4-12EO) were observed at both works, which had equal sludge ages of 13 days. However, the biological activity in terms of milligrams of estrogen removed per day per tonne of biomass was found to be 50-60% more efficient in the nitrifying/denitrifying activated sludge works compared to the works which additionallyincorporated phosphorusremoval. A temperature reduction of 6 degrees C had no impact on the removal of free estrogens, but removal of the conjugated estrone-3-sulfate was reduced by 20%. The apparent biomass sorption (LogKp) values were greater in the nitrifying/denitrifying works than those in the nitrifying/denitrifying works with phosphorus removal for both steroid estrogens and honylphenolic compounds possibly indicating a different cell surface structure and therefore microbial population. The difference in biological activity (mg tonne(-1) d(-1)) identified in this study, of up to seven times, suggests thatthere is the potential for enhancing the removal of estrogens and nonylphenols if more detailed knowledge of the factors responsible for these differences can be identified and maximized, thus potentially improving the quality of receiving waters.

Influence of manganese and ammonium oxidation on the removal of 17 alpha-ethinylestradiol (EE2)

Flow-through reactors with manganese oxides were examined for their capacity to remove 17 alpha-ethinylestradiol (EE2) at microg L(-1) and ng L(-1) range from synthetic wastewater treatment plant (WWTP) effluent. The mineral MnO(2) reactors removed 93% at a volumetric loading rate (B(V)) of 5 microg EE2 L(-1) d(-1) and from a B(V) of 40 microg EE2 L(-1) d(-1) on, these reactors showed 75% EE2 removal. With the biologically produced manganese oxides, only 57% EE2 was removed at 40 microg EE2 L(-1) d(-1). EE2 removal in the ng L(-1) range was 84%. The ammonium present in the influent (10 mg N L(-1)) was nitrified and ammonia-oxidizing bacteria (AOB) were found to be of prime importance for the degradation of EE2. Remarkably, EE2 removal by AOB continued for a period of 4 months after depleting NH(4)(+) in the influent. EE2 removal by manganese-oxidizing bacteria was inhibited by NH(4)(+). These results indicate that the metabolic properties of nitrifiers can be employed to polish water containing EE2 based estrogenic activity.

Biodegradation and removal of pharmaceuticals and personal care products in treatment systems: a review

Pharmaceuticals and personal care products (PPCPs) have been the focus of much recent research as concerns rise about their occurrence in bodies of water worldwide. In an effort to characterize the risk and determine the prevalence of these micropollutants in lakes and rivers, many researchers are examining PPCP removal from impaired water during wastewater treatment and water recycling (soil passage) processes. Biodegradation studies and projects considering combinations of biodegradation and other removal processes have been conducted over a wide range of compound categories and therapeutic classes, as well as across different systems and scales of study. This review summarizes the extent of PPCP removal observed in these various systems.

Comparison of predicted and measured concentrations of selected pharmaceuticals, fragrances and hormones in Spanish sewage

A review of consumption and excretion rates of 17 pharmaceuticals, two musk fragrances and two hormones by the Spanish population in 2003 was performed. For that purpose, three different models were used: (i) extrapolation of the per capita use in Europe to the number of inhabitants of Spain for musk fragrances; (ii) annual prescription items multiplied by the average daily dose for pharmaceuticals and; (iii) excretion rates of different groups of population for hormones. This information enabled the prediction of the expected concentrations (PEC) entering sewage treatment plants (STPs), which were subsequently compared with the measured environmental concentrations (MEC) in raw sewage. Annual drugs consumption in Spain ranges from few kilograms (Oxazepam and 17alpha-ethinylestradiol) to several hundred of tons (Ibuprofen). The quantities of musks used accounts for 110-450 kg d(-1) and the total amount of hormones excreted daily reaches almost 1 kg d(-1). 12 out of 21 selected substances were predicted to be present in raw sewage influent at concentrations greater than 100 ng l(-1) and these predicted concentrations fitted with the measured values for half of them (Carbamazepine, Diazepam, Ibuprofen, Naproxen, Diclofenac, Sulfamethoxazole, Roxithromycin, Erythromycin and 17alpha-ethinylestradiol).

Effect of municipal sewage treatment plant effluent on bioaccumulation of polychlorinated biphenyls and polybrominated diphenyl ethers in the recipient water

Water, sediment, and aquatic species including plankton, fish, and turtles were collected from a small lake in Beijing, which receives effluent discharged from a large sewage treatment plant (STP). The samples were examined to investigate polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) releases from a STP and their distributions in the lake. The accumulations of sigma 12PBDEs and BDE-209 in the sediment were 62.3 and 1150 ng/cm2, respectively, while that of sigma PCBs was 99.3 ng/cm2. BDE-209 was detected in more than 50% of the aquatic species. A strong linear correlation (R2 = 0.92) was found between sigma 12PBDEs and sigma PCBs levels in aquatic species but not in sediments. The different PBDE congener profiles in sediments and biota samples suggest metabolic debromination in the sampled fish. Bioaccumulations of PBDEs and PCBs were found in aquatic species.The logarithm bioaccumulation factor (BAF) decreases with the number of bromines in PBDEs molecules, while the log BAF versus the number of chlorines in PCBs appears to be parabolic. Biomagnifications of these compounds were not obvious in the food web by analysis of the relationship between sigma 12PBDEs or sigma PCBs levels and the trophic level of aquatic biota species.