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

Investigating the presence, distribution and risk of pharmaceutically active compounds (PhACs) in wastewater treatment plants, river sediments and fish

The increasing consumption of medicines and the lack of efficient technologies in wastewater treatment plants (WWTPs) can release pharmaceutically active compounds (PhACs) into any given river with the subsequent risk to the environment and human health. To assess the occurrence and transfer pathways of PhACs through the river ecosystem, 22 PhACs and one metabolite were analyzed in WWTPs, river sediments and fish collected alongside the Tagus River basin between 2020 and 2022. All the matrices presented at least two drugs being azithromycin the only one quantified in all of them. Analgesics, anti-inflammatories, antihypertensives, antidepressants and beta-blockers were the main PhACs in influents, with median concentrations up to 19 μg/L. In effluents, antihypertensives and antidepressants were the PhACs with the highest contribution. For acetaminophen, ibuprofen, ketoprofen, naproxen, atorvastatin, azithromycin, clarithromycin, sulfamethoxazole, trimethoprim, and valsartan WWTPs treatments reached removal efficiencies above 75%. Compounds with a high tendency to bind to organic matter were retained in sludge (clotrimazole, 96 ng/g before digester, 100%). However, results showed that applied treatments were not effective in removing PhACs from this matrix. Although the total mass balance revealed a high removal rate of some PhACs, many of them were still present in the effluent and their release into rivers became the main source of PhAC pollution of the aquatic ecosystem. The most hydrophobic ones (irbesartan, 24 ng/g, 61%), positively charged (o-desmethylvenlafaxine, 95 ng/g, 68%) and those with affinity to organic matter (clotrimazole, 21 ng/g, 61%) reached sediment samples. Only clotrimazole (7.8 ng/g) and azithromycin (160 ng/g) were found in fish samples. Risk assessment revealed a high risk for (i) acetaminophen, clarithromycin, erythromycin A, and venlafaxine in phototrophic organisms and (ii) acetaminophen and venlafaxine in fish.

Insights into the efficiencies of different biological treatment systems for pharmaceuticals removal: A review

This review presents a comprehensive analysis of current research on biological treatment processes for removing pharmaceutical compounds (PhCs) from wastewater. Unlike previous studies on this topic, our study specifically delves into the effectiveness and drawbacks of various treatment approaches such as traditional wastewater treatment facilities (WWTP), membrane bioreactors (MBRs), constructed wetlands (CW), and moving bed biofilm reactors (MBBR). Through the examination and synthesis of information gathered from more than 200 research studies, we have created a comprehensive database that delves into the effectiveness of eliminating 19 particular PhCs, including commonly studied compounds such as acetaminophen, ibuprofen, diclofenac, naproxen, ketoprofen, indomethacin, salicylic acid, codeine, and fenoprofen, amoxicillin, azithromycin, ciprofloxacin, ofloxacin, tetracycline, atenolol, propranolol, and metoprolol. This resource provides a depth and scope of information that was previously lacking in this area of study. Notably, among these pharmaceuticals, azithromycin demonstrated the highest removal rates across all examined treatment systems, with the exception of WWTPs, while carbamazepine consistently exhibited the lowest removal efficiencies across various systems. The analysis showcases the diverse results in removal efficiency impacted by factors such as system configuration, operation specifics, and environmental circumstances. The findings emphasize the critical need for continued innovation and research, specifically recommending the integration of advanced oxidation processes (AOPs) with existing biological treatment methods to improve the breakdown of recalcitrant compounds like carbamazepine. PRACTITIONER POINTS: Persistent pharmaceuticals harm aquatic ecosystems and human health. Biological systems show varying pharmaceutical removal efficiencies. Enhancing HRT and SRT improves removal but adds complexity and costs. Tailored treatment approaches needed based on contaminants and conditions.

Efficient PPCPs removal from wastewaters via a novel A/O-MBBR system: Transition towards circular economy in the water sector

As industrial and agricultural production depends on water supply, it is crucial for economic development. The available freshwater reserves on Earth are insufficient to meet humanity's growing demands. This study establishes a three-stage anoxic/oxic (A/O)-moving bed biofilm reactor (MBBR) system. The study evaluated the wastewater purification capacity of the system in summer and winter, examined the system's removal efficiency of 10 pharmaceuticals and personal care products (PPCPs) from the water, and analyzed the composition of microbial communities. Results indicate that the system effectively removes pollutants and PPCPs, with the aerobic tanks in the first two A/O stages playing a significant role in PPCP removal. The system is effective in removing four kinds of pollutants: AMP, IBU, CLR, and CAF, and the removal efficiency of CAF is up to 99.2%. Seasonal variations significantly affect the removal of PPCPs and bacterial growth, leading to changes in bacterial species. At the genus level, 41 bacterial types presented different effects in response to temperature changes, with Trichoderma and c_OM190_unclassified being the most affected. This study provides essential theoretical support for reducing pollutant levels and improving water recycling and economic efficiency.

Feasibility of organic micropollutant removal from municipal wastewaters by algal treatment vs. activated sludge treatment: Comparison based on non-targeted organic compound analysis

Sustainability and life-cycle concerns about the conventional activated sludge (CAS) process for wastewater treatment have been driving the development of energy-efficient, greener alternatives. Feasibility of an algal-based wastewater treatment (A-WWT) system has been demonstrated recently as a possible alternative, capable of simultaneous nutrient and energy recovery. This study compared capabilities of the A-WWT and CAS systems in removing organic micropollutants (OMP). Initial assessments based on surrogate organic measures and fluorescence excitation-emission matrix (FEEM) scans revealed that the A-WWT system achieved higher removals of organics than the CAS system. However, effluents of both systems contained residual organic matter, necessitating further OMP assessment for a rigorous comparison. A novel ultrahigh-performance liquid chromatography- Fourier transform mass spectrometry (UPLC-FTMS)-based non-targeted screening approach was adopted here for residual OMP analysis. This approach confirmed that the A-WWT system resulted in better OMP removal, eliminating 329 compounds and partially reducing 472 compounds, compared to 206 eliminations and 410 partial reductions by the CAS system. Mass spectra signal corresponding to some OMPs increased with treatment while some transformation products were observed following treatment. Higher OMP reduction in the A-WWT system with concurrent reductions of biodegradable carbon, nutrients, and pathogens in a single-step while producing energy and nutrient rich algal biomass underscore its potential as a greener alternative for wastewater treatment.

Occurrence of micropollutants in rural domestic wastewater in Zhejiang Province, China and corresponding wastewater-based epidemiology analysis

By 2021, rural regions in China were occupied by over 500 million residents, generating an annual volume of 19.5 billion m3 of rural domestic wastewater (RDW). This study aimed to investigate the occurrence and removal of micropollutants (MPs) in RDW treatment facilities and to perform a corresponding wastewater-based epidemiology analysis (WBE). Our findings indicated the significantly high levels of influent MPs, particularly pharmaceuticals, such as ofloxacin and diclofenac being most prevalent (ranging from several to tens of μg/L) across different facilities. After various treatments, regular water indexes in the effluent, like NH3 -N and COD, have basically satisfied the local discharge standard. However, the concentration of certain dominant MPs in effluent remained notably high, ranging from hundreds of ng/L to several μg/L. The risk quotients of MPs like diclofenac, ciprofloxacin, ofloxacin, sulfamethoxazole, diuron, and isoproturon were all above 1 in the effluent, signifying significant hazards to aquatic organisms. The quantitative meta-analysis revealed higher average standardized removal efficiency for membrane bioreactor (MBR) treatment (-11 %) compared to anaerobic/anoxic/aerobic (A2O) treatment (11 %), indicating the higher efficiency of MBR treatment in outperforming the A2O as a secondary treatment. Additionally, employing biofilter as a tertiary treatment proved to be more effective as compared to flocculation-air flotation and artificial wetlands. Moreover, the results of WBE analysis showed that diclofenac and ofloxacin emerged as the most commonly used pharmaceuticals (of seven), with consumption levels recorded at 1222 and 517 mg/(d·103 capita), with daily defined doses per day per 103 capita of 12.2/1000 and 1.29/1000, respectively. This study addresses the existing knowledge gaps regarding the occurrence and removal of MPs in RDW and offers valuable insights into pharmaceutical consumption patterns in rural regions, thereby improving our understanding of public health.

Exploring the correlations between epi indicators of COVID-19 and the concentration of pharmaceutical compounds in wastewater treatment plants in Northern Portugal

The COVID-19 pandemic caused by the SARS-CoV-2 virus led to changes in the lifestyle and human behaviour, which resulted in different consumption patterns of some classes of pharmaceuticals including curative, symptom-relieving, and psychotropic drugs. The trends in the consumption of these compounds are related to their concentrations in wastewater systems, since incompletely metabolised drugs (or their metabolites back transformed into the parental form) may be detected and quantified by analytical methods. Pharmaceuticals are highly recalcitrant compounds and conventional activated sludge processes implemented in wastewater treatment plants (WWTP) are ineffective at degrading these substances. As a results, these compounds end up in waterways or accumulate in the sludge, being a serious concern given their potential effects on ecosystems and public health. Therefore, it is crucial to evaluate the presence of pharmaceuticals in water and sludge to assist in the search for more effective processes. In this work, eight pharmaceuticals from five therapeutic classes were analysed in wastewater and sludge samples collected in two WWTP located in the Northern Portugal, during the third COVID-19 epidemic wave in Portugal. The two WWTP demonstrated a similar pattern with respect to the concentration levels in that period. However, the drugs loads reaching each WWTP were dissimilar when normalising the concentrations to the inlet flow rate. Acetaminophen (ACET) was the compound detected at highest concentrations in aqueous samples of both WWTP (98. 516 μg L ^- 1 in WWTP2 and 123. 506 μg L ^- 1in WWTP1), indicating that this drug is extensively used without the need of a prescription, known of general public knowledge as an antipyretic and analgesic agent to treat pain and fever. The concentrations determined in the sludge samples were below 1.65 µg g ^- 1 in both WWTP, the highest value being found for azithromycin (AZT). This result may be justified by the physico-chemical characteristics of the compound that favour its adsorption to the sludge surface through ionic interactions. It was not possible to establish a clear relationship between the incidence of COVID-19 cases in the sewer catchment and the concentration of drugs detected in the same period. However, looking at the data obtained, the high incidence of COVID-19 in January 2021 is in line with the high concentration of drugs detected in the aqueous and sludge samples but prediction of drug load from viral load data was unfeasible.

MCDA-DEA approach to construct a composite indicator for effluents from WWTPs considering the influence of PPCPs

Considering current water situation, reuse is an effective solution to meet water demand and reduce pressure on conventional water sources. However, pharmaceutical and personal care products (PPCPs) in effluents from wastewater treatment plants (WWTPs) decrease their quality and suitability. With the aim of identifying and monitoring both the influence of PPCPs and the suitability of effluents to be reused, this study proposes the development of a composite indicator (CI) related to PPCP presence in WWTPs, through the common weight multi-criteria decision analysis (MCDA)-data envelopment analysis (DEA) model. Obtaining a CI for PPCPs is a novel approach in the published literature, showing a new perspective in PPCP management and their influence in wastewater treatment. Furthermore, this study proposes an improvement on MCDA-DEA model which maintains the initial hierarchy obtained for the units analyzed. The development of CI is based on information about the technological, environmental, social, and biological issues of WWTPs. Results show that 4 of the 33 WWTPs analysed had the best CI values, meaning that their effluents have lower environmental impact. The development of a CI related to PPCPs in WWTPs suggests that further steps are needed to manage the WWTP effluents. Hence, the need to implement preventive measures in WWTPs has been shown, even though the removal of PPCPs is not yet part of European law. This work highlights the importance of considering PPCPs as priority pollutants in wastewater management and reuse frameworks, to guarantee low environmental impact and adapt wastewater reuse based on a circular economy approach. HIGHLIGHTS: Emerging contaminants (PPCPs) are used as effluent quality indicators. A composite indicator for PPCPs performance has been developed through MCDA-DEA model. Indicator obtained allow decision makers implementing concrete actions to assess effluent quality. Results show the improvement capacity of the effluents quality through PPCPs removing.

Removal of nutrients and veterinary antibiotics from manure-free piggery wastewater in a packed-bed A/O process at normal atmospheric temperature

A packed-bed anaerobic-aerobic reactor (PBAOR) with two anaerobic and two aerobic compartments was constructed to treat manure-free piggery wastewater which was characterized by high ammonium (NH4⁺-N) and low ratio of chemical oxygen demand (COD) to total nitrogen (TN). Performed for 60 days at the normal atmospheric temperature of 25 °C with a constant hydraulic retention time of 32 h and reflux ratio of 2.0, a stable state in pollutants removal was obtained in the PBAOR. Within the next routine operation process, the removal of COD, NH4⁺-N and TN was above 85.7%, 98.2% and 85.8%, with a residual less than 81.7, 7.2 and 39.9 mg L^-1 in effluent, respectively. Twelve veterinary antibiotics classified into tetracyclines (TCs), sulphonamides (SAs) and fluoroquinolones (FQs) were detected from the piggery wastewater. The PBAOR was effective in removing TCs and SAs with an average removal of 74.8% and 93.3%, respectively, but presented a negative removal for FQs. Most COD in the piggery wastewater was mainly removed in the first two anaerobic compartments along with an obvious removal of TCs and SAs, while the TN were mainly removed in the last two aerobic compartments with the negative removal of FQs.

Assessment of the aerobic and anaerobic biodegradation of contaminants of emerging concern in sludge using batch reactors

This work explores the degradation of xenobiotic compounds in aerobic and anaerobic batch reactors. Different inoculums were spiked with nine emerging contaminants at nominal concentrations ranging between 1 to 2 mg/L (ibuprofen, diclofenac, naproxen, acesulfame, sucralose, aspartame, cyclamate, linear alkylbenzene sulfonates, and secondary alkyl sulfonates). Ethanol was used as co-substrate in the anaerobic reactors. We found that the kinetic decay was faster in the aerobic reactors inoculated with a Spanish (S_pn) inoculum compared to a Brazilian (B_rz) inoculum, resulting in rection rates for LAS and SAS of 2.67 ± 3.6 h^-1 and 5.09 ± 6 h^-1 for the B_rz reactors, and 1.3 ± 0.1 h^-1 and 1.5 ± 0.2 h^-1 for the S_pn reactors, respectively. There was no evidence of LAS and SAS degradation under anaerobic conditions within 72 days; nonetheless, under aerobic conditions, these surfactants were removed by both the B_rz and S_pn inoculums (up to 86.2 ± 9.4% and 74.3 ± 0.7%, respectively) within 10 days. The artificial sweeteners were not removed under aerobic conditions, whereas we could observe a steady decrease in the anaerobic reactors containing the S_pn inoculum. Ethanol aided in the degradation of surfactants in anaerobic environments. Proteiniphilum, Paraclostridium, Arcobacter, Proteiniclasticum, Acinetobacter, Roseomonas, Aquamicrobium, Moheibacter, Leucobacter, Synergistes, Cyanobacteria, Serratia, and Desulfobulbus were the main microorganisms identified in this study.

Individual and synergic effect of carbamazepine and diclofenac in the removal of organic matter from an expanded granular bed anaerobic reactor

Due to the negative effects caused to the natural environment by the presence of pharmaceutical-type traces and other pollutants in wastewater, it is necessary to develop and optimize efficient treatment systems. This study evaluated the effect of carbamazepine (CBZ) and diclofenac (DCF) on the behavior of seven EGSB (expanded granular sludge bed) anaerobic reactors at laboratory scale, using chromatographic and physicochemical analyses of the influent, effluent, and the biomass contained in the reactors. The results showed that CBZ had a greater effect on the removal and behavior of microorganisms than DCF, with average efficiencies of 34.04 ± 18.58%, 20.76 ± 8.51% and 16.29 ± 11.08% during stage II, III and IV, respectively, for CBZ, and 92.37 ± 12.74%, 26.77 ± 5.90% and 22.28 ± 9.60% during stage II, III and IV, respectively, for DCF. Additionally, it was found that the interaction of the co-substrate used (sodium acetate) in conjunction with the pharmaceutical compounds decreased the efficiency of the system in terms of the removal of analytes.

Removal efficiency of organic micropollutants in successive wastewater treatment steps in a full-scale wastewater treatment plant: Bench-scale application of tertiary treatment processes to improve removal of organic micropollutants persisting after secondary treatment

The goal of this study was to investigate the occurrence and removal of 52 organic micropollutants (OMPs) during each wastewater treatment step in a full-scale wastewater treatment plant (WWTP). Pharmaceuticals such as metformin, acetaminophen, caffeine, ibuprofen, cimetidine and naproxen were found with high average concentrations in the influent. Most OMPs were not affected by the primary treatment (removal <10%), while secondary biological treatment contributed the most to overall removal of the OMPs. Among the three lanes of the secondary treatment of the WWTP, a combined anaerobic-anoxic-oxic process followed by a membrane bioreactor (A2O-MBR) process effectively facilitated removal of the OMPs (96%) using a different redox: a conventional activated sludge (CAS) process exhibited removal of approximately 85% of total concentrations of the OMPs, while a Modified Ludzack-Ettinger (MLE) process achieved approximately 92.1% removal. Removal of more than 50% of the concentrations of 13 targeted OMPs was observed in the secondary effluent (except for metformin showing only 3.8% removal) via adsorption with powdered activated carbon (PAC) as additional tertiary treatment. Metformin, inadequately removed by additional tertiary treatments, was effectively removed by a biological activated carbon (BAC) process, reaching a removal efficiency of 90.5%. To increase the removal of the amounts and types of OMPs with various physico-chemical properties, hybrid processes through a combination of diverse advanced treatment should be tailored to WWTPs.

Spatio-temporal distribution of pharmaceutically active compounds in the River Cauvery and its tributaries, South India

Pharmaceutically active compounds (PhACs) present in the environment are a great threat to human well-being and the ecosystem. Eventhough recognized as the pharmacy of the world", studies addressing the distribution of PhACs in the Indian environment are scarce. Hence, in the current study, selected PhACs, heavy metals (HMs), and physicochemical parameters (PCPs) were measured from the surface waters of the River Cauvery during the pre- and post-monsoon. PhACs such as caffeine, carbamazepine, and diclofenac were detected in most samples, whereas topiramate, ibuprofen, and verapamil were found only in few stations. In contrast, the distribution of ciprofloxacin, atenolol, and isoprenaline was strongly influenced by the seasonal pattern (p < 0.05). PhACs such as loperamide, glafenine, erythromycin, and gemfibrozil were not detected during the study. Distribution of PhACs based on average concentration (ng/L) are, CBZ (205.62) > CAF (114.09) > DCF (28.51) > CIP (25.23) > ATL (18.86) > IPL (13.91) > PPL (11.26) > TCS (10.39) > IBF (7.34) > TPT (3.09) > VPL (1.16). Bivariate and multivariate statistical analyses have revealed a positive correlation expressed by the majority of the PhACs with PCPs (COD, TOC), nutrients (TN, TP), and HMs (Pb, Mn, Ni) in the range from 0.540** to 0.961**(p < 0.01). Whereas, DO revealed negative correlation with most of the parameters in the range from -0.559** to -0.831** (p < 0.01). A high average concentration of PhACs was recorded in the upstream (52.08 ng/L) and wastewater discharge points (55.60 ng/L). Further, the environmental risk assessment study has identified the higher risk exhibited by TCS (RQ: 3.29) and CAF (RQ: 38.82) on algae and Daphnia respectively. The study portrays the distribution of emerging contaminants in the River Cauvery and its tributaries and also delivers preliminary data about the distribution of isoprenaline, topiramate, verapamil, and perindopril in the Indian freshwater system.

Human Drug Pollution in the Aquatic System: The Biochemical Responses of Danio rerio Adults

Simple Summary

The release of medicinal products for human use in the aquatic environment is now a serious problem, and can be fatal for the organisms that live there. Danio rerio is a freshwater fish that provides the possibility to study the effects of these pollutants on the health of aquatic organisms. The results of the various existing scientific studies are scarce and conflicting. Here, we review the scientific studies that have analyzed these effects, highlighting that the impacts of drugs are evident in the biochemical responses of these animals.

Abstract

To date, drug pollution in aquatic systems is an urgent issue, and Danio rerio is a model organism to study the toxicological effects of environmental pollutants. The scientific literature has analyzed the effect of human drug pollution on the biochemical responses in the tissues of D. rerio adults. However, the information is still scarce and conflicting, making it difficult to understand its real impact. The scientific studies are not consistent with each other and, until now, no one has grouped their results to create a baseline of knowledge of the possible impacts. In this review, the analysis of literature data highlights that the effects of drugs on adult zebrafishes depend on various factors, such as the tissue analyzed, the drug concentration and the sex of the individuals. Furthermore, the most influenced biochemical responses concern enzymes (e.g., antioxidants and hydrolase enzymes) and total protein and hormonal levels. Pinpointing the situation to date would improve the understanding of the chronic effects of human drug pollution, helping both to reduce it in the aquatic systems and then to draw up regulations to control this type of pollution.

Examination of single-stage anaerobic and anoxic/aerobic and dual-stage anaerobic-anoxic/aerobic digestion to remove pharmaceuticals from municipal biosolids

Many trace contaminants of emerging concern (CECs) including a number of pharmaceutically active compounds are not effectively removed during conventional wastewater treatment processes and instead accumulate in wastewater sludge. Unfortunately, many existing sludge stabilization treatments such as anaerobic digestion (AD) also have limited effectiveness against many of these CECs including the four pharmaceuticals ibuprofen, diclofenac, carbamazepine, and azithromycin which can then enter the environment through the disposal or land application of biosolids. Single-stage AD, single-stage cycling aerobic-anoxic (AERO/ANOX) and sequential digesters (AD followed by an AERO/ANOX digester) at sludge retention times (SRT) of 5 to 20-days were evaluated side-by-side to assess their effectiveness in removing pharmaceuticals and conventional organic matter. Single-stage ADs (35 °C) and AERO/ANOX (22 °C) digesters effectively removed total solids while sequential AD + AERO/ANOX digesters offered further improvements. Ibuprofen was not effectively removed during AD and resulted in up to a 23 ± 8% accumulation. However, ibuprofen was completely removed during AERO/ANOX digestion and in several sequential digestion scenarios. Each type of digestion was less effective against carbamazepine with slight (3 ± 2%) accumulations to low levels (14 ± 1%) of removals in each type of digestion studied. Diclofenac was more effectively removed with up 30 ± 3% to 39 ± 4% reductions in the single-stage digesters (AD and AERO/ANOX, respectively). While sequential digestion scenarios with the longest aerobic SRTs significantly increased diclofenac removals from their first-stage digesters, scenarios with the longest anaerobic SRTs actually decreased removals from first-stage digesters, possibly due to reversible biotransformation of diclofenac conjugates/metabolites. Up to 43 ± 6% of azithromycin was removed in AERO/ANOX digesters, while the best performing sequential-digester scenario removed up to 63 ± 7% of azithromycin. This study shows that different digester configurations can reduce the CEC burden in biosolids while also greatly reducing their volumes for disposal, although none can remove CECs completely.

Do initial concentration and activated sludge seasonality affect pharmaceutical biotransformation rate constants?

Pharmaceuticals find their way to the aquatic environment via wastewater treatment plants (WWTPs). Biotransformation plays an important role in mitigating environmental risks; however, a mechanistic understanding of involved processes is limited. The aim of this study was to evaluate potential relationships between first-order biotransformation rate constants (k_b) of nine pharmaceuticals and initial concentration of the selected compounds, and sampling season of the used activated sludge inocula. Four-day bottle experiments were performed with activated sludge from WWTP Groesbeek (The Netherlands) of two different seasons, summer and winter, spiked with two environmentally relevant concentrations (3 and 30 nM) of pharmaceuticals. Concentrations of the compounds were measured by LC-MS/MS, microbial community composition was assessed by 16S rRNA gene amplicon sequencing, and k_b values were calculated. The biodegradable pharmaceuticals were acetaminophen, metformin, metoprolol, terbutaline, and phenazone (ranked from high to low biotransformation rates). Carbamazepine, diatrizoic acid, diclofenac, and fluoxetine were not converted. Summer and winter inocula did not show significant differences in microbial community composition, but resulted in a slightly different k_b for some pharmaceuticals. Likely microbial activity was responsible instead of community composition. In the same inoculum, different k_b values were measured, depending on initial concentration. In general, biodegradable compounds had a higher k_b when the initial concentration was higher. This demonstrates that Michealis-Menten kinetic theory has shortcomings for some pharmaceuticals at low, environmentally relevant concentrations and that the pharmaceutical concentration should be taken into account when measuring the k_b in order to reliably predict the fate of pharmaceuticals in the WWTP. KEY POINTS: • Biotransformation and sorption of pharmaceuticals were assessed in activated sludge. • Higher initial concentrations resulted in higher biotransformation rate constants for biodegradable pharmaceuticals. • Summer and winter inocula produced slightly different biotransformation rate constants although microbial community composition did not significantly change.

Removal of Pharmaceuticals from Water by Adsorption and Advanced Oxidation Processes: State of the Art and Trends

Pharmaceutical products have become a necessary part of life. Several studies have demonstrated that indirect exposure of humans to pharmaceuticals through the water could cause negative effects. Raw sewage and wastewater effluents are the major sources of pharmaceuticals found in surface waters and drinking water. Therefore, it is important to consider and characterize the efficiency of pharmaceutical removal during wastewater and drinking-water treatment processes. Various treatment options have been investigated for the removal/reduction of drugs (e.g., antibiotics, NSAIDs, analgesics) using conventional or biological treatments, such as activated sludge processes or bio-filtration, respectively. The efficiency of these processes ranges from 20–90%. Comparatively, advanced wastewater treatment processes, such as reverse osmosis, ozonation and advanced oxidation technologies, can achieve higher removal rates for drugs. Pharmaceuticals and their metabolites undergo natural attenuation by adsorption and solar oxidation. Therefore, pharmaceuticals in water sources even at trace concentrations would have undergone removal through biological processes and, if applicable, combined adsorption and photocatalytic degradation wastewater treatment processes. This review provides an overview of the conventional and advanced technologies for the removal of pharmaceutical compounds from water sources. It also sheds light on the key points behind adsorption and photocatalysis.

Effect of concentration and hydraulic reaction time on the removal of pharmaceutical compounds in a membrane bioreactor inoculated with activated sludge

Pharmaceuticals are often not fully removed in wastewater treatment plants (WWTPs) and are thus being detected at trace levels in water bodies all over the world posing a risk to numerous organisms. These organic micropollutants (OMPs) reach WWTPs at concentrations sometimes too low to serve as growth substrate for microorganisms; thus, co-metabolism is thought to be the main conversion mechanism. In this study, the microbial removal of six pharmaceuticals was investigated in a membrane bioreactor at increasing concentrations (4-800 nM) of the compounds and using three different hydraulic retention times (HRT; 1, 3.5 and 5 days). The bioreactor was inoculated with activated sludge from a municipal WWTP and fed with ammonium, acetate and methanol as main growth substrates to mimic co-metabolism. Each pharmaceutical had a different average removal efficiency: acetaminophen (100%) > fluoxetine (50%) > metoprolol (25%) > diclofenac (20%) > metformin (15%) > carbamazepine (10%). Higher pharmaceutical influent concentrations proportionally increased the removal rate of each compound, but surprisingly not the removal percentage. Furthermore, only metformin removal improved to 80-100% when HRT or biomass concentration was increased. Microbial community changes were followed with 16S rRNA gene amplicon sequencing in response to the increment of pharmaceutical concentration: Nitrospirae and Planctomycetes 16S rRNA relative gene abundance decreased, whereas Acidobacteria and Bacteroidetes increased. Remarkably, the Dokdonella genus, previously implicated in acetaminophen metabolism, showed a 30-fold increase in abundance at the highest concentration of pharmaceuticals applied. Taken together, these results suggest that the incomplete removal of most pharmaceutical compounds in WWTPs is dependent on neither concentration nor reaction time. Accordingly, we propose a chemical equilibrium or a growth substrate limitation as the responsible mechanisms of the incomplete removal. Finally, Dokdonella could be the main acetaminophen degrader under activated sludge conditions, and non-antibiotic pharmaceuticals might still be toxic to relevant WWTP bacteria.

Is sequential batch reactor an efficient technology to protect recipient against non-steroidal anti-inflammatory drugs and paracetamol in treated wastewater?

The tested facility was a wastewater treatment plant (WWTP) in Swarzewo, where the wastewater treatment takes place in aeration chambers with activated sludge using sequential batch reactors (SBRs). The concentration of the following pharmaceuticals: ibuprofen, paracetamol, flurbiprofen, naproxen, diclofenac, and its metabolites 5OH-diclofenac and 4OH-diclofenac was tested in influents and effluents. Simultaneously, the conventional parameters were characterised. The removal of conventional pollutants was high (94.4-99.5%). At the same time, the removal of pharmaceuticals was variable. In the case of diclofenac and its metabolites, the concentration in the effluent was higher than in the influents. The risk quotients (RQs) calculated for analyzed pharmaceuticals suggest low environmental risk for selected species. However, negative impact for the biota due to the chronic presence of diclofenac cannot be excluded. It can be concluded that the SBRs, similarly to traditional flow activated sludge technology, are not efficient in the removal of target pharmaceuticals.

Comparison of anaerobic, cycling aerobic/anoxic, and sequential anaerobic/aerobic/anoxic digestion to remove triclosan and triclosan metabolites from municipal biosolids

The antimicrobial triclosan (TCS) is a pervasive and persistent environmental micropollutant which can contaminate land, biota, and water through the land application of biosolids. Many existing sludge management techniques have limited effectiveness against TCS and TCS metabolites including triclosan-sulfate (TCS-SO₄). The objective of this study was to evaluate the impacts of different digestion types (anaerobic, aerobic/anoxic, and sequential anaerobic + aerobic/anoxic), temperatures, and digester sludge retention times (SRTs) on the destruction of organic matter, and on TCS/TCS metabolites. Conventional mesophilic anaerobic digesters (AD), room temperature cycling aerobic/anoxic digesters (AERO/ANOX), and sequential AD + AERO/ANOX digesters were all effective in removing organic matter. The optimum single-stage AD, and AERO/ANOX scenarios were both 20-day SRTs which had 52.3 ± 1.4 and 47.1 ± 3.7% chemical oxygen demand (COD) removals, respectively. Sequential AD + AERO/ANOX digesters improved organic matter destruction, removing up to 68.2 ± 2.1% of COD at an 8-day AD + 12-day AERO/ANOX second-stage (mesophilic) SRTs. While AD showed modest levels of TCS removals (all <40%), TCS was substantially more degradable aerobically with AERO/ANOX removing up to 80.3 ± 2.5% of TCS and nearly all TCS-SO₄ entering the digester at a 20-day SRT. Sequential AD + AERO/ANOX removed virtually all TCS-SO₄ entering the system and improved TCS removals from first stage ADs. However, they were less effective than a single-stage AERO/ANOX digester operating at the same overall SRT. These results demonstrate that AERO/ANOX and sequential AD + AERO/ANOX processes could be used to reduce the amount of TCS, TCS-SO₄ and TCS-related compounds in digested sludge, minimizing the environmental burden of the land application of biosolids.

Tandem anaerobic-aerobic degradation of ranitidine, diclofenac, and simvastatin in domestic sewage

There is a consensus among scientists that domestic sewage treatment plants are the main sources of drugs entry into the aquatic environment. Therefore, this work studies the biodegradation of the drugs ranitidine (RNT), diclofenac (DCF), and simvastatin (SVT) (50 μg L^-1, each), in real domestic sewage, using a continuous anaerobic-aerobic reactor with immobilized biomass and an anaerobic batch reactor. The continuous anaerobic-aerobic reactor was operated for 6 months with hydraulic retention time (HRT) of 8 h. The initial degradation rates and the maximum oxidation capacities (MOC) of the system were estimated, achieving 90, 72, and 62% removals and 100, 93, and 72% of MOC for RNT, DCF and SVT, respectively, as well as 71% removal of soluble chemical oxygen demand (COD). RNT was degraded throughout the reactor, while DCF was degraded mainly in the two anaerobic chambers and SVT in the first anaerobic chamber. Anaerobic batches were used for the identification of biodegradation by-products (2,6-dichloro-N-(2-methylphenyl) aniline and simvastatin acid), the evaluation of the specific methanogenic activity (SMA) inhibition, and the estimation of acute and chronic ecotoxicities using the ECOSAR 1.11 software. The present study showed that, even at environmental concentrations, RNT, DCF, and SVT were capable of inhibiting the SMA. Lipophilicities dictated the behavior of those three drugs. The greater their lipophilicities, the greater the SMA inhibition and their ecotoxicity.

Effects of Low Concentration of Selected Analgesics and Successive Bioaugmentation of the Activated Sludge on Its Activity and Metabolic Diversity

In this study, we evaluated the impact of the successive bioaugmentation of the activated sludge (AS) with the defined bacterial consortium on the activity and functional capacity of the AS microorganisms. In parallel, the removal of low concentrations of the selected non-steroidal anti-inflammatory drugs (ibuprofen, naproxen, diclofenac) and analgesic paracetamol was studied. We found that the addition of the bacterial consortium consisting of three pharmaceuticals-degrading strains Bacillus thuringiensis B1 (2015b), Stenotrophomonas maltophilia KB2, and Pseudomonas moorei KB4 into the AS did not cause any significant changes in the biomass abundance and metabolic activity of the AS microorganisms. Although, the successive bioaugmentation of the AS caused a slight increase in the metabolic diversity, the intensity of carbohydrates usage, and metabolic richness. Microorganisms in the bioaugmented and non-bioaugmented AS were able to degrade the mixture of the analyzed drugs with similar efficiency, however, diclofenac was removed more effectively in the bioaugmented AS. Several metabolites were identified and efficiently utilized, with the exception of 4-OH diclofenac. Two new diclofenac-degrading strains assigned as Serratia proteamaculans AS4 and Rahnella bruchi AS7 were isolated from the diclofenac-treated AS.

Selected Pharmaceuticals in Different Aquatic Compartments: Part I-Source, Fate and Occurrence

Potential risks associated with releases of human pharmaceuticals into the environment have become an increasingly important issue in environmental health. This concern has been driven by the widespread detection of pharmaceuticals in all aquatic compartments. Therefore, 22 pharmaceuticals, 6 metabolites and transformation products, belonging to 7 therapeutic groups, were selected to perform a systematic review on their source, fate and occurrence in different aquatic compartments, important issues to tackle the Water Framework Directive (WFD). The results obtained evidence that concentrations of pharmaceuticals are present, in decreasing order, in wastewater influents (WWIs), wastewater effluents (WWEs) and surface waters, with values up to 14 mg L⁻¹ for ibuprofen in WWIs. The therapeutic groups which presented higher detection frequencies and concentrations were anti-inflammatories, antiepileptics, antibiotics and lipid regulators. These results present a broad and specialized background, enabling a complete overview on the occurrence of pharmaceuticals in the aquatic compartments.

Distribution and Removal of Pharmaceuticals in Liquid and Solid Phases in the Unit Processes of Sewage Treatment Plants

In this study, we analyzed 27 pharmaceuticals in liquid and solid phase samples collected from the unit processes of four different sewage treatment plants (STPs) to evaluate their distribution and behavior of the pharmaceuticals. The examination of the relative distributions of various categories of pharmaceuticals in the influent showed that non-steroidal anti-inflammatory drugs (NSAIDs) were the most dominant. While the relative distribution of antibiotics in the influent was not high (i.e., 3%–5%), it increased to 14%–30% in the effluent. In the four STPs, the mass load of the target pharmaceuticals was reduced by 88%–95% mainly in the biological treatment process, whereas the ratio of pharmaceuticals in waste sludge to those in the influent (w/w) was only 2%. In all the STPs, the removal efficiencies for the stimulant caffeine, NSAIDs (acetaminophen, naproxen, and acetylsalicylic acid), and the antibiotic cefradine were high; they were removed mainly by biological processes. Certain compounds, such as the NSAID ketoprofen, contrast agent iopromide, lipid regulator gemfibrozil, and antibiotic sulfamethoxazole, showed varying removal efficiencies depending on the contribution of biodegradation and sludge sorption. In addition, a quantitative meta-analysis was performed to compare the pharmaceutical removal efficiencies of the biological treatment processes in the four STPs, which were a membrane bioreactor (MBR) process, sequencing batch reactor (SBR) process, anaerobic–anoxic–oxic (A2O) process, and moving-bed biofilm reactor (MBBR) process. Among the biological processes, the removal efficiency was in the order of MBR > SBR > A2O > MBBR. Among the tertiary treatment processes investigated, powdered activated carbon showed the highest removal efficiency of 18%–63% for gemfibrozil, ibuprofen, ketoprofen, atenolol, cimetidine, and trimethoprim.

Metabolite identification of ibuprofen biodegradation by Patulibacter medicamentivorans under aerobic conditions

Ibuprofen (IBU) is a non-steroidal anti-inflammatory drug that is becoming increasingly recognized as an important micropollutant to be monitored in wastewater treatment plants (WWTP), since it has been detected in effluents at the µg L^-1 level. The IBU metabolites from biological degradation are not completely understood and can represent a threat to natural aquatic systems. P. medicamentivorans was previously isolated from WWTP sludge and found to be capable of IBU degradation. The aerobic biodegradation of ibuprofen by this organism was investigated in a batch lab-scale reactor for the identification of the metabolites formed. The metabolites were analysed and putatively identified by HPLC-DAD-MS/MS and GC-MS and biodegradation pathways were proposed. The toxicity and the biodegradability potential of the metabolites were also investigated. The results showed that IBU biotransformation was achieved by hydroxylation followed by the formation of a carboxylic acid in the IBU molecule and by the formation of a catechol, allowing the aromatic ring cleavage. Two biodegradation pathways were proposed: in one, the metabolites generated from the enzymatic action correspond to a less biodegradable chemical structure of the intermediate products (isobutylbenzene and 3-isobutylphenol), with comparatively higher toxicity; in the other mechanism, more oxidable chemical structures were formed with less toxicity and higher biodegradability. This suggests that the biodegradation of IBU by P. medicamentivorans can take place by more than one mechanism regarding the enzymes formed by this Gram-positive bacterium, with subsequent oxidation of the parent compound to overall more soluble and less toxic compounds to fish, daphnia and green algae.

The utilization of reclaimed water: Possible risks arising from waterborne contaminants

Increasing interest of seeking substitutable water resources accrues from shortage of freshwater. One of the options considered is reclaimed water (also designated as recycled water) that has been widely used in daily life. Although reclaimed water can serve as a feasible reliever of water pressure, attention about its technologies and potential risks is growing in the meantime. Most established wastewater treatment plants (WWTPs) predate many new contaminants, which means treatment processes cannot ensure to dislodge certain contaminants completely from origin water. Furthermore, a wide range of factors, such as seasons and influent variations, affect occurrence and concentration of reclaimed water-borne contaminants, making research about quality of reclaimed water especially significant. Many reclaimed water-borne contaminants, including biological and chemical contaminants, are toxic to human health, and complex wastewater matrix may aggravate water quality of concern. The widespread use of reclaimed water continues to be a concern on agriculture, ecological environment and human health. This study aims to: 1) provide a critical review about occurrence and profiles of diverse contaminants in the treated reclaimed water, 2) discuss the possibility to avoid the secondary pollution in reuse of reclaimed water, and 3) reveal the prospective consequences of using reclaimed water on agriculture, ecological environment and human health.

Mass loads, source apportionment, and risk estimation of organic micropollutants from hospital and municipal wastewater in recipient catchments

Understanding the occurrence and sources of organic micropollutants (OMPs) in aquatic environments is essential for environmental risk assessment and adequate interventions to secure good status of aquatic environments. The occurrence and source apportionment of 77 OMPs in the River Fyris catchment (Uppsala, Sweden) were investigated by comparing hospital wastewater, wastewater treatment plant (WWTP) effluent, and surface water. Hospital wastewater was identified as an important source for some classes of OMPs, e.g., antibiotics (number of OMPs (n) = 6) and antidepressants (n = 4), contributing 38% and 31%, respectively, of the mass loads in total WWTP influent. Painkillers (n = 5) and hormones (n = 3), originating mainly from urban Uppsala, contributed 94% and 95%, respectively. WWTP removal efficiency varied from 100% for acetaminophen to <0% for i.e. clindamycin, lamotrigine, bicalutamide, and sucralose. In the recipient River Fyris, the ΣOMP concentration downstream of the WWTP (738 ng L^-1) was more than double that upstream (338 ng L^-1), demonstrating the high impact of the WWTP on recipient water quality. Surface water risk quotients (RQs) showed a moderate risk of adverse chronic effects (RQ > 0.1) for trimethoprim, norsertraline, and metoprolol downstream of the WWTP, and for norsertraline in the recipient river upstream and Lake Ekoln downstream of the WWTP. Recipient metoprolol and trimethoprim, compounds poorly removed in the WWTP, mainly (>90%) originated from wastewater from urban Uppsala, whereas recipient norsertraline originated upstream of the city. No risk compound was apparently sourced from hospital wastewater.

Correlating effluent concentrations and bench-scale experiments to assess the transformation of endocrine active compounds in wastewater by UV or chlorination disinfection

Transformation of endocrine active compounds (EACs) by either chlorination (Cl-D) or UV disinfection (UV-D) was studied by field sampling and bench-scale validation studies. Field testing assessed concentration of 13 EACs in effluent at two Chicago area 250 MGD wastewater reclamation plants (WRP) over two years. One WRP uses chlorination/dechlorination while the other employs UV disinfection. Target compounds included bupropion, carbamazepine, citalopram, duloxetine, estradiol, estrone, fluoxetine, nonylphenol, norfluoxetine, norsertraline, paroxetine, sertraline, and venlafaxine. Concentrations of 9/13 target compounds were partially reduced after disinfection (5-65% reduction). None of the target compounds were fully transformed by either chlorination or UV treatment at the WRP scale. In bench-scale experiments each compound was spiked into deionized water or effluent and treated in a process mimicking plant-scale disinfection to validate transformations. Correlation was observed between compounds that were transformed in bench-testing and those that decreased in concentration in post-disinfection WRP effluent (10/13 compounds). A survey of potential reaction products was made. Chlorination of some amine containing compounds produced chloramine by-products that reverted to the initial form after dechlorination. Transformation products produced upon simulated UV disinfection were more diverse. Laboratory UV-induced transformation was generally more effective under stirred conditions, suggesting that indirect photo-induced reactions may predominate over direct photolysis.

Impact of on-site wastewater infiltration systems on organic contaminants in groundwater and recipient waters

On-site sewage treatment facilities, particularly septic systems combined with soil infiltration, can be an important source of emerging organic contaminants in groundwater and surface water and thus represent a significant source of environmental and human exposure. Two infiltration systems in Åre municipality, Sweden, were examined to assess the occurrence of contaminants in groundwater and their fate and transport during infiltration. Groundwater samples, recipient surface water samples, and wastewater samples from septic tanks were collected from 2016 to 2017 covering all climatological seasons. These samples were analysed for a total of 103 contaminants, including pharmaceuticals, personal care products, organic phosphorus flame-retardants, plasticisers, perfluoroalkyl substances, and food additives. Fourteen of 103 contaminants showed 100% detection frequency in groundwater at concentrations in the low ng L^-1 to low μg L^-1 range. Of the compounds analysed, tris(2‑butoxyethyl) phosphate, sucralose, caffeine, and benzophenone showed high abundancy with maximum concentrations in the μg L^-1 range. The data were normalised for dilution using chloride and sucralose as commonly applied tracers; however, the level of sucralose decreased significantly during infiltration and it is thus suboptimal as a sewage water tracer. Large differences between the two infiltration sites were observed in detection frequencies and concentrations in groundwater, which could be attributed to the system design and the contaminant's migration time from release to sampling point. Seasonal variation was observed for selected chemicals, and the more hydrophobic chemicals showed a higher tendency for attenuation, indicating sorption as a major retention mechanism. A moderate environmental risk to aquatic organisms was estimated in adjacent surface water for galaxolide, tris(1‑chloro‑2‑propyl) phosphate, and tris(2‑butoxyethyl) phosphate. Due to this site-dependency and potential environmental risks, further studies are needed on infiltration systems in different settings and on alternative treatment techniques to reduce the contaminant discharge from on-site sewage treatment facilities.

Anaerobic biodegradation of pharmaceutical compounds: New insights into the pharmaceutical-degrading bacteria

Antibiotics and hormones are among the most concerning trace contaminants in the environment. Therefore, the present work aimed to identify anaerobic microorganisms with the ability to remove pharmaceutical products (PhPs) belonging to these two classes (ciprofloxacin, 17β-estradiol and sulfamethoxazole) under different anaerobic conditions, and to elucidate the bio-removal mechanisms involved. Ciprofloxacin was efficiently biodegraded under both nitrate- and sulfate-reducing conditions reaching a PhP removal superior to 80%, whereas 17β-estradiol was only biodegraded under nitrate-reducing conditions reaching a removal of 84%. No biodegradation of sulfamethoxazole was observed. In nitrate-reducing conditions the ciprofloxacin-degrading community was composed of Comamonas, Arcobacter, Dysgonomonas, Macellibacteroides and Actinomyces, genera while Comamonas and Castellaniella were the main bacteria present in the 17β-estradiol-degrading community. In sulfate-reducing conditions the community was mainly composed by bacteria affiliated to Desulfovibrio, Enterococcus and Peptostreeptococcus. Interestingly, the PhP under study were biodegraded even in the absence of additional carbon source, with 85% of ciprofloxacin removed under sulfate-reducing conditions and 62% and 83% of ciprofloxacin and estradiol removed, respectively, under nitrate-reducing conditions. This work provides new insights into anaerobic bioremediation of PhP and novel PhP-degrading bacteria.

Advanced oxidation process-mediated removal of pharmaceuticals from water: A review

Pharmaceuticals, which are frequently detected in natural and wastewater bodies as well as drinking water have attracted considerable attention, because they do not readily biodegrade and may persist and remain toxic. As a result, pharmaceutical residues pose on-going and potential health and environmental risks. To tackle these emerging contaminants, advanced oxidation processes (AOPs) such as photo-Fenton, sonolysis, electrochemical oxidation, radiation and ozonation etc. have been applied to remove pharmaceuticals. These processes utilize the high reactivity of hydroxyl radicals to progressively oxidize organic compounds to innocuous products. This review provides an overview of the findings from recent studies, which have applied AOPs to degrade pharmaceutical compounds. Included is a discussion that links various factors of TiO₂-mediated photocatalytic treatment to its effectiveness in degrading pharmaceutical residues. This review furthermore highlights the success of AOPs in the removal of pharmaceuticals from different water matrices and recommendations for future studies are outlined.

Quantifying variability in removal efficiencies of chemicals in activated sludge wastewater treatment plants - a meta-analytical approach

Large variations in removal efficiencies (REs) of chemicals have been reported for monitoring studies of activated sludge wastewater treatment plants (WWTPs). In this work, we conducted a meta-analysis on REs (1539 data points) for a set of 209 chemicals consisting of fragrances, surfactants, and pharmaceuticals in order to assess the drivers of the variability relating to inherent properties of the chemicals and operational parameters of activated sludge WWTPs. For a reduced dataset (n = 542), we developed a mixed-effect model (meta-regression) to explore the observed variability in REs for the chemicals using three chemical specific factors and four WWTP-related parameters. The overall removal efficiency of the set of chemicals was 82.1% (95% CI 75.2-87.1%, N = 1539). Our model accounted for 17% of the total variability in REs, while the process-based model SimpleTreat did not perform better than the average of the measured REs. We identified that, after accounting for other factors potentially influencing RE, readily biodegradable compounds were better removed than non-readily biodegradable ones. Further, we showed that REs increased with increasing sludge retention times (SRTs), especially for non-readily biodegradable compounds. Finally, our model highlighted a decrease in RE with increasing KOC. The counterintuitive relationship to KOC stresses the need for a better understanding of electrochemical interactions influencing the RE of ionisable chemicals. In addition, we highlighted the need to improve the modelling of chemicals that undergo deconjugation when predicting RE. Our meta-analysis represents a first step in better explaining the observed variability in measured REs of chemicals. It can be of particular help to prioritize the improvements required in existing process-based models to predict removal efficiencies of chemicals in WWTPs.

What happens with organic micropollutants during UV disinfection in WWTPs? A global perspective from laboratory to full-scale

The phototransformation of 18 organic micropollutants (OMPs) commonly detected in wastewater treatment plant (WWTP) effluents was examined attempting to explain their fate during UV disinfection in WWTPs. For this purpose, a lab-scale UV reactor (lamp emitting at 254nm) was used to study the influence of the operational conditions (UV dose, temperature and water matrix) on OMPs abatement and disinfection efficiency. Chemical properties of OMPs and the quality of treated effluent were identified as key factors affecting the phototransformation rate of these compounds. Sampling campaigns were carried out at the inlet and outlet of UV systems of three WWTPs, and the results evidenced that only the most photosensitive compounds, such as sulfamethoxazole and diclofenac, are eliminated. Therefore, despite UV treatment is an effective technology to phototransform OMPs, the UV doses typically applied for disinfection (10-50mJ/cm²) are not sufficient to remove them. Consequently, small modifications (increase of UV dose, use of catalysts) should be applied in WWTPs to enhance the abatement of OMPs in UV systems.

Mimicking and Inhibiting Urea Hydrolysis in Nonwater Urinals

Nonwater urinals are critical in the implementation of building-scale water conservation and urine diversion systems. However, because of the composition of urine and the prevalence of the urease enzyme that hydrolyzes urea, minerals readily precipitate in nonwater urinals and pipes. This leads to clogging, malodor, and possible replacement of nonwater urinals with flush urinals. Accordingly, the goal of this research was to provide an improved understanding of the urea hydrolysis process in nonwater urinals to benefit water conservation and phosphate recovery efforts. Acetic acid addition was used in nonwater urinals to inhibit the urea hydrolysis reaction by lowering the pH, thereby making the precipitation of calcium- and magnesium-containing minerals less favorable. Of the acids tested, 2.5 mL of 2500 mequiv/L acetic acid added after every urination event was able to inhibit urea hydrolysis in synthetic urine and real urine as indicated by the pH and conductivity of the effluent urine. Acid addition also allowed for 43% more phosphate recovery via struvite precipitation in the acetic acid addition synthetic urine than the synthetic urine with no acid addition.

Oxidation of clofibric acid in aqueous solution using a non-thermal plasma discharge or gamma radiation

In this work, we study degradation of clofibric acid (CFA) in aqueous solution using either ionizing radiation from a⁶⁰Co source or a non-thermal plasma produced by discharges in the air above the solution. The results obtained with the two technologies are compared in terms of effectiveness of CFA degradation and its by-products. In both cases the CFA degradation follows a quasi-exponential decay in time well modelled by a kinetic scheme which considers the competition between CFA and all reaction intermediates for the reactive species generated in solution as well as the amount of the end product formed. A new degradation law is deduced to explain the results. Although the end-product CO₂ was detected and the CFA conversion found to be very high under the studied conditions, HPLC analysis reveals several degradation intermediates still bearing the aromatic ring with the chlorine substituent. The extent of mineralization is rather limited. The energy yield is found to be higher in the gamma radiation experiments.

Occurrence, fate, and mass balance of different classes of pharmaceuticals and personal care products in an anaerobic-anoxic-oxic wastewater treatment plant in Xiamen, China

In this study, the occurrence and fate of 49 pharmaceuticals and personal care products (PPCPs) were investigated in an anaerobic-anoxic-oxic (A2/O) wastewater treatment plant (WWTP) for seven consecutive days using 24-h composite sampling technique. Special emphasis was placed to understand the distribution of PPCPs in dissolved and adsorbed phase, and to evaluate PPCP fate in different treatment units. Among the 49 PPCPs, 40 PPCPs in influent, 36 in effluent, 29 in sludge and 23 in suspended solids were detected at least once during sampling. Non-steroidal anti-inflammatory drugs (NSAIDs) and a stimulant were predominant PPCPs in influent whereas antibiotics were predominant in sludge, effluent and suspended solids. Removal efficiencies from the aqueous phase based on the dissolved PPCPs showed variable contribution in removing different PPCPs under screen and grit chamber, anaerobic treatment, anoxic treatment, oxic treatment and sedimentation-UV treatments, with the highest removal percentage by anaerobic process in terms of both individual and overall treatment. Mass load analysis showed that 352 g PPCPs enter the WWTP daily while 14.5 g and 58.1 g were discharged through effluent and excess sludge to the receiving sea water and soil applications, respectively. Mass balance analysis based on both aqueous and suspended PPCPs showed 280 g (79.4%) mass of influent PPCPs was lost along the wastewater treatment processes, mainly due to degradation/transformation.

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.

Direct and indirect photolysis of seven micropollutants in secondary effluent from a wastewater lagoon

The photodegradation of seven micropollutants commonly found in municipal wastewater, namely caffeine, carbamazepine, diuron, simazine, sulfamethoxazole, triclosan and 2,4-D, was investigated in pure water and secondary effluent to understand the direct and indirect photolysis of these compounds under natural sunlight irradiation. Sulfamethoxazole and triclosan were readily photodegraded with half-lives of 5.8 and 1.8 h, respectively, whilst the others were relatively resistant towards sunlight irradiation. Enhanced degradation was observed in secondary effluent compared with in the pure water matrix for all compounds, except for triclosan. It was confirmed that hydroxyl radicals played an important role in the photodegradation of the micropollutants while singlet oxygen may also play a role. The contribution of hydroxyl radical to the overall degradation of the five compounds that were resistant to direct sunlight accounted for 32%-70%. The impact of humic acid and nitrate, two known photosensitisers and wastewater components, on the photodegradation of the seven micropollutants in pure water was investigated under simulated solar radiation. The presence of nitrate promoted the photochemical loss of all seven micropollutants, however, humic acid caused promotion or inhibition, depending on the characteristics of the micropollutant. Humic acid enhanced the photolytic degradation of caffeine, sulfamethoxazole and diuron, while it hindered the photodegradation of the other four compounds by absorbing the available irradiation energy and/or reforming the parent compound. Furthermore, it was shown that there was only a small increase (up to 15%) in photodegradation of the compounds at 25 °C compared with that at 10 °C in the simulated system.

Behaviour of the main nonsteroidal anti-inflammatory drugs in a membrane bioreactor treating urban wastewater at high hydraulic- and sludge-retention time

The behaviour and removal efficiency of ibuprofen (IBU), diclofenac (DCF), ketoprofen (KPF), and naproxen (NPX) during the real urban wastewater treatment by an experimental full-scale MBR working at high sludge and hydraulic retention time (SRT, HRT) were determined. The MBR worked in denitrification/nitrification conformation at 35.4h of HRT (Q=0.45m³/h), 37 d of SRT and a recirculation flow rate of 4Q. The experiments were made under steady-state conditions, reaching a biodegradable organic matter removal higher than 99.5%. The MBR system showed similar removal capacity for IBU, NPX, and KTP (>95%), whose main transformation occurred in the aerobic reactor with a low contribution from the anoxic reactor. The system worked with complete nitrification, also achieving an effective retention of the unbiodegradable organic matter due to recirculation. DCF removal was low with negative removal yields for several samplings. Both removal and increase transformation of DCF also occurred in the aerobic reactor, this not being observed in the anoxic one. DCF tends to accumulate in the system and to be recirculated. Thus, during the sampling in which DCF influent concentration decreases, removal yields turn negative. The increase of DCF concentration in the aerobic bioreactor also contributes to the negative removal yields.

Occurrence and behaviour of pharmaceutical compounds in a Portuguese wastewater treatment plant: Removal efficiency through conventional treatment processes

Wastewater treatments can eliminate or remove a substantial amount of pharmaceutical active compounds (PhACs), but there may still be significant concentrations of them in effluents discharged into surface water bodies. Beirolas wastewater treatment plant (WWTP) is located in the Lisbon area and makes its effluent discharges into Tagus estuary (Portugal). The main objective of this study is to quantify a group of 32 PhACs in the different treatments used in this WWTP. Twelve sampling campaigns of wastewater belonging to the different treatments were made in 2013-2014 in order to study their removal efficiency. The wastewaters were analysed by solid phase extraction (SPE) and ultra-performance liquid chromatography coupled with tandem mass detection (UPLC-MS/MS). The anti-diabetics were the most frequently found in wastewater influent (WWI) and wastewater effluent (WWE) (208 and 1.7 μg/L, respectively), followed by analgesics/antipyretics (135 μg/L and < LOQ, respectively), psychostimulants (113 and 0.49 μg/L, respectively), non-steroidal anti-inflammatory drugs (33 and 2.6 μg/L, respectively), antibiotics (5.2 and 1.8 μg/L, respectively), antilipidemics (1.6 and 0.24 μg/L, respectively), anticonvulsants (1.5 and 0.63 μg/L, respectively) and beta blockers (1.3 and 0.51 μg/L, respectively). A snapshot of the ability of each treatment step to remove these target PhACs is provided, and it was found that global efficiency is strongly dependent on the efficiency of secondary treatment. Seasonal occurrence and removal efficiency was also monitored, and they did not show a significant seasonal trend.

Occurrence and behavior of selected pharmaceuticals during riverbank filtration in The Republic of Serbia

The objectives of the research are to determine the occurrence of pharmaceuticals in surface water and groundwater in the Republic of Serbia and to identify significant effects of river-water purification through riverbank filtration, concerning oxic conditions and hydrogeological conditions of alluvial aquifers in Serbia. Between 2009 and 2015, a total of 19 studied pharmaceuticals and metabolites were analyzed in 184 samples, 10 were detected in surface water, and 8 in groundwater. Carbamazepine and metamizole metabolites N-acetyl-4-amino-antipyrine (4-AAA) and N-formyl-4-amino-antipyrine (4-FAA) have the highest frequency of occurrence in surface water (57.3-68.8 %) and in groundwater (19.5-43.9 %), respectively. Highest detected concentrations were for 4-AAA (520 ng/L) and 4-FAA (248 ng/L) in surface water as well as in groundwater (4-AAA 128 ng/L and 4-FAA 150 ng/L). Results showed that riverbank filtration sites with different hydrogeological and oxic conditions could significantly remove investigated pharmaceuticals. Percentage of removal during riverbank filtration was determined for carbamazepine (65.4 %), trimethoprim (100 %), 4-AAA (91.2 %), and 4-FAA (70 %) for all investigated locations. Based on the available data for three specific locations (Danube River alluvion, Sava River alluvion, and Velika Morava River alluvion), results showed that besides oxic conditions, residence time of groundwater in alluvial aquifer and ratio of infiltrated water from river to the well play very important role in the quality of groundwater. These results are extremely important for better understanding of self-purification potential of alluvial aquifers and protection from potential impacts of anthropogenic pollution to the groundwater sources in the Republic of Serbia.

Assessment of full-scale biological nutrient removal systems upgraded with physico-chemical processes for the removal of emerging pollutants present in wastewaters from Mexico

Two full-scale biological nutrient removal systems upgraded with three physico-chemical processes (coagulation, chemical precipitation, and neutral Fenton) were evaluated in order to determine the removal of emerging pollutants (EPs) present in municipal wastewater from Mexico. Between 41 and 55 EPs were detected in the influents of two wastewater treatment plants (WWTPs), including personal care products (PPCPs), antibiotics, analgesics, antiepileptics, antilipidemics, antihypertensives, antiseptics, stimulants, and hormones. Emerging pollutants were detected at concentrations ranging from 0.69ng/L to 94,600ng/L. High concentrations of emerging pollutants were found during dry season. WWTP 1, integrated by oxidation ditches and UV light lamps, showed removal efficiencies of EPs between 20% and 22%. On the other hand, WWTP 2 consisted of anaerobic/anoxic/aerobic tanks coupled with two disinfection processes; chlorine dioxide and UV light lamps, for which the removal of EPs was significant (up to 80%). The concentrations of emerging pollutants in WWTP 1 effluent was found within a range<limit of quantification (LOQ) to 3770ng/L. For WWTP 2, the concentrations of the emerging pollutants in the effluent were below 210ng/L. WWTP 2 showed high emerging pollutant removals, compared to those of WWTP 1, due to a greater activity of the simultaneous nitrification-denitrification processes, hydraulic retention time, and solids retention time. The compounds that were more persistent with removals below 50% in both effluents were: carbamazepine, dehydronifedipine, meprobamate, sertraline, propranolol, propoxyphene, norverapamil, diazepam, alprazolam, sulfamethoxazole, metoprolol, ofloxacin, norfloxacin, fluoxetine, erythromycin-H2O, diphenhydramine, dehydronifedipine, clarithromycin, hydrochlorothiazide, and albuterol. The application of neutral Fenton reaction as post-treatment for the two effluents from the WWTPs is promising for the removal of emerging pollutants (up to 100%) and for assuring high quality of treated water.

Life cycle assessment and costing of urine source separation: Focus on nonsteroidal anti-inflammatory drug removal

Urine source separation has the potential to reduce pharmaceutical loading to the environment, while enhancing nutrient recovery. The focus of this life cycle assessment (LCA) was to evaluate the environmental impacts and economic costs to manage nonsteroidal anti-inflammatory drugs (NSAIDs) (i.e., diclofenac, ibuprofen, ketoprofen and naproxen) and nutrients in human urine. Urine source separation was compared with centralized wastewater treatment (WWT) (biological or upgraded with ozonation). The current treatment method (i.e., centralized biological WWT) was compared with hypothetical treatment scenarios (i.e., centralized biological WWT upgraded with ozonation, and urine source separation). Alternative urine source separation scenarios included varying collection and handling methods (i.e., collection by vacuum truck, vacuum sewer, or decentralized treatment), pharmaceuticals removal by ion-exchange, and struvite precipitation. Urine source separation scenarios had 90% lower environmental impact (based on the TRACI impact assessment method) compared with the centralized wastewater scenarios due to reduced potable water production for flush water, reduced electricity use at the wastewater treatment plant, and nutrient offsets from struvite precipitation. Despite the greatest reduction of pharmaceutical toxicity, centralized treatment upgraded with ozone had the greatest ecotoxicity impacts due to ozonation operation and infrastructure. Among urine source separation scenarios, decentralized treatment of urine and centralized treatment of urine collected by vacuum truck had negligible cost differences compared with centralized wastewater treatment. Centralized treatment of urine collected by vacuum sewer and centralized treatment with ozone cost 30% more compared with conventional wastewater treatment.

Bioaccumulation of five pharmaceuticals at multiple trophic levels in an aquatic food web - Insights from a field experiment

Pharmaceuticals derived from manufacturing and human consumption contaminate surface waters worldwide. To what extent such pharmaceutical contamination accumulates and disperses over time in different compartments of aquatic food webs is not well known. In this study we assess to what extent five pharmaceuticals (diphenhydramine, oxazepam, trimethoprim, diclofenac, and hydroxyzine) are taken up by fish (European perch) and four aquatic invertebrate taxa (damselfly larvae, mayfly larvae, waterlouse, and ramshorn snail), by tracing their bioconcentrations over several months in a semi-natural large-scale (pond) system. The results suggest both significant differences among drugs in their capacity to bioaccumulate and differences among species in uptake. While no support for in situ uptake of diclofenac and trimethoprim was found, oxazepam, diphenhydramine, and hydroxyzine were detected in all analyzed species. Here, the highest bioaccumulation factor (tissue:water ratio) was found for hydroxyzine. In the food web, the highest concentrations were found in the benthic species ramshorn snail and waterlouse, indicating that bottom-living organism at lower trophic positions are the prime receivers of the pharmaceuticals. In general, concentrations in the biota decreased over time in response to decreasing water concentrations. However, two interesting exceptions to this trend were noted. First, mayfly larvae (primarily grazers) showed peak concentrations (a fourfold increase) of oxazepam, diphenhydramine, and hydroxyzine about 30days after initial addition of pharmaceuticals. Second, perch (top-predator) showed an increase in concentrations of oxazepam throughout the study period. Our results show that drugs can remain bioavailable for aquatic organism for long time periods (weeks to months) and even re-enter the food web at a later time. As such, for an understanding of accumulation and dispersion of pharmaceuticals in aquatic food webs, detailed ecological knowledge is required.

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.

Fate and behaviour of diclofenac during hydrothermal carbonization

Hydrothermal carbonization (HTC) has become an esteemed method to convert sewage sludge into biochar. Besides dewatering and disinfection the process is suggested to reduce the micropollutant load, which would be beneficial for the use of biochar as fertilizer. This study was designed to examine reduction of micropollutants and formation of transformation products during HTC using the example of diclofenac. We investigated compounds' removal at HTC conditions in inert experiments and in real samples. Results showed that HTC temperature (>190 °C) and pressure (∼15 bar) have the potential to fully degrade diclofenac in inert experiments and spiked sewage sludge (>99%) within 1 h. However, interfering effects hinder full removal in native samples resulting in 44% remaining diclofenac. Additionally, a combination of suspected-target and non-target analysis using LC-MS/MS and LC-HRMS resulted in the determination of six transformation products. These products have been reported in biochar from HTC for the first time, although other studies described them for other processes like advanced oxidation. Based on the detected transformation products, we proposed a degradation mechanism reflecting HTC reactions such as dehydroxylation and decarboxylation.