River rejuvenation in urban India for enhancing living conditions through integrated water resources management

India, being a developing country, faces big challenges in ensuring water, sanitation, and hygiene (WASH) for all. This case study presents the performance evaluation of a large wastewater management and sanitation-related infrastructure in a metropolitan city in North India. "Dravyavati River Project" is the major sanitation program of the water-stressed Jaipur city based on the concept of river rejuvenation of the long-lost Dravyavati River which flows across the city. The project envisages integrated urban water management such that it aims at the collection and treatment of wastewater (sewage network and treatment plants), safe disposal, ensuring continuous unpolluted flow, geological and ecological integrity to strengthen public health, to reduce the impact of water stress on the total water cycle by promoting groundwater recharge, and improvement in biodiversity. The technical assessment is based on the primary and secondary data collection of field samples and laboratory analysis of influent and effluent samples collected from the five sewage treatment plants (STPs). The results suggest that the project has largely delivered the envisaged environment, public well-being, and ecological and socioeconomic benefits, but there are substantial gaps in the conceived outputs and actual performance. The challenge lies in bridging these gaps and overcoming operational inefficiencies to ensure the sustainability of the Dravyavati River rejuvenation.

Abundance, characterization, and removal of microplastics in different technology-based sewage treatment plants discharging into the middle stretch of the Ganga River, India

Sewage treatment plants (STPs) are considered as a prominent source for releasing microplastics (MPs) into the riverine systems. Though MPs abundance and removal efficacy in different secondary treatment technique-based STPs have been extensively studied worldwide, such studies are scarce in Indian conditions. Herein, this study comprehensively assesses MPs abundance, characterization, and their removal in the selected secondary treatment technique-based STPs discharging into the middle stretch of the Ganga River in India. MPs concentration (n/L) in influent and effluent of the STPs varied between 42 ± 10 to 150 ± 19 and 3 ± 1 to 22 ± 5, respectively. Overall, the primary treatment stage was observed to remove MPs by 23-42 %, while the secondary treatment stage removed MPs by 67-90 %. Selected technique-based STPs exhibited varying MPs removal efficacies as follows: SBR (94 %), TF (90 %), AL (88 %), UASB (87 %), ASP (85 %), FAB (84 %), and Bio-tower (77 %). MPs ranging from 50 to 250 μm were the dominant sizes, with PP, PE, and PS being the prevalent polymers. The Ganga River receives about 3 × 108 MPs/day from STP effluents, and an estimated 4.5 × 107 MPs/day are released via the sludge. This comprehensive assessment of MPs abundance and removal from different technology-based Indian STPs will allow the comparison of the generated dataset with similar studies worldwide.

Occurrence, removal, and risk assessment of emerging contaminants in aquatic products processing sewage treatment plants

Emerging contaminants (ECs) in aquatic environments have attracted attention due to their wide distribution and potential ecotoxicities. Sewage treatment plants (STPs) are proven to be the major source of ECs in the aquatic environment, while there remains insufficient understanding of the removal and risk assessment of ECs in STPs. Here, we clarified the degradation and risk impact of 13 ECs in two aquatic product processing sewage treatment plants (APPSTPs) along the southeast coast of China. The concentrations of ECs followed the order: endocrine-disrupting chemicals (1877.85-15,398.02 ng/L in influent, 3.37-44.47 ng/L in effluent) >  > sulfonamide antibiotics (SAs, 75.14-906.19 ng/L in influent, 1.14-15.33 ng/L in effluent) > pharmaceutical and personal care products (PPCPs, 44.47-589.93 ng/L in influent, 2.54-34.16 ng/L in effluent) ≈ fluoroquinolone antibiotic (54.76-434.83 ng/L in influent, 10.75-32.82 ng/L in effluent) > other antibiotics (16.21-51.96 ng/L in influent, 0.68-6.17 ng/L in effluent). Moreover, the concentrations of PPCPs (decreased by 55.33-87.65% in peak fishing season) and antibiotics (increased by 44.99% in peak fishing season) were affected by fishing activities. In particular, the sequencing batch reactor (SBR) process had a better removal effect than the anaerobic-anoxic-oxic (A2/O) process on the treatment of some contaminants (e.g., norfloxacin and nonylphenol). Risk evaluations of ECs demonstrated that nonylphenol and SAs were at high- and low-risk states, respectively. Overall, our results provide important information for the degradation treatment of ECs, which is essential for pollutant management policy formulation.

Antibiotics in sewage treatment plants, receiving water bodies and groundwater of Chennai city and the suburb, South India: Occurrence, removal efficiencies, and risk assessment

The presence of antibiotics in the aqueous environment can alter the water microbiome, inducing antimicrobial resistance genes. Hence, the occurrence of 18 antibiotics belonging to sulfonamides, fluoroquinolones, tetracyclines, phenicols, and macrolides classes were investigated in surface water, groundwater, and sewage treatment plants in Chennai city and the suburbs. Fluoroquinolones had the maximum detection frequency in both influent and effluent samples of urban and suburban STPs, with ofloxacin and ciprofloxacin showing the highest influent concentrations. Erythromycin was the predominant antibiotic in surface water samples with an average concentration of 194.4 ng/L. All the detected antibiotic concentrations were higher in the Buckingham Canal compared to those in Adyar and Cooum rivers, possibly due to direct sewer outfalls in the canal. In groundwater samples, ciprofloxacin showed the highest levels with an average of 20.48 ng/L and the concentrations were comparable to those of surface water. The average sulfamethazine concentration in groundwater (5.2 ng/L) was found to be slightly higher than that of the surface water and much higher than the STP influent concentrations. High levels of ciprofloxacin and sulfamethazine in groundwater may be because of their high solubility and wide use. Moreover, erythromycin was completely removed after treatment in urban STPs; FQs showed relatively lesser removal efficiency (2.4-54%) in urban STPs and (8-44%) in suburban STP. Tetracyclines and phenicols were not detected in any of the samples. Ciprofloxacin and azithromycin in surface water pose a high risk in terms of estimated antibiotic resistance. This study revealed that the measured surface water concentration of antibiotics were 500 times higher for some compounds than the predicted calculated concentrations from STP effluents. Therefore, we suspect the direct sewage outlets or open drains might play an important role in contaminating surface water bodies in Chennai city.

Selective Recovery of Estrogenic Endocrine Disruptors from 48 Environmental Samples Using a Substrate for Activity-Specific Concentration

hER-MIP is a molecularly imprinted polymer (MIP) that has been shown to selectively collect human estrogen receptor (hER) binding active substances. However, environmental samples contain various chemicals depending on the location and regional differences, and the hER binding activity depends on the sample type. Thus, the general applicability of hER-MIP to actual environmental samples must be elucidated. In this study, 48 environmental samples were collected and screened with hER-MIP, and a yeast assay was performed to evaluate the adsorption characteristics of the samples according to the adsorption and elution fractions. The results showed that hER-MIP collects hER binding active substances almost selectively but does not collect constitutive androstane receptor (CAR) binding active substances selectively. CAR binding activity was detected in the adsorbed fraction because several hER binding active substances also demonstrate CAR binding activity.

Occurrences and removal of pharmaceutical and personal care products from aquatic systems using advanced treatment- A review

Pharmaceuticals, personal care items, steroid hormones, and agrochemicals are among the synthetic and indigenous products that make up micropollutants, also known as emerging contaminants. Pharmaceutical and personal care products (PPPs) are a class of developing micropollutants that can harm living organisms even at low concentrations. Many are detected in surface water and wastewater from the treatment process, with quantities ranging from ng L-1 to gL-1; however, residual PPPs at dangerously high levels have indeed recently been recognized in the ecosystem. Residential sewage treatment plant (STP) dump the largest majority of these pollutants into the environment on a regular basis. As a result of its robust structure, it has a longer lifespan in the environment. This review article discusses how surface water pollutants such pesticides, petroleum hydrocarbons, and perfluorinated compounds affect water quality, as well as the most cost-effective adsorbents for removing these PPPs. The goal of this study is to provide information about the origins of PPP, as well as diagnostic procedures and treatment options. Research on developing contaminants is also aimed at evaluating the efficacy and affordability of adsorption.

SARS-CoV-2 RNA surveillance in large to small centralized wastewater treatment plants preceding the third COVID-19 resurgence in Bangkok, Thailand

Wastewater surveillance for SARS-CoV-2 RNA has been a successful indicator of COVID-19 outbreaks in populations prior to clinical testing. However, this has been mostly conducted in high-income countries, which means there is a dearth of performance investigations in low- and middle-income countries with different socio-economic settings. This study evaluated the applicability of SARS-CoV-2 RNA monitoring in wastewater (n = 132) to inform COVID-19 infection in the city of Bangkok, Thailand using CDC N1 and N2 RT-qPCR assays. Wastewater influents (n = 112) and effluents (n = 20) were collected from 19 centralized wastewater treatment plants (WWTPs) comprising four large, four medium, and 11 small WWTPs during seven sampling events from January to April 2021 prior to the third COVID-19 resurgence that was officially declared in April 2021. The CDC N1 assay showed higher detection rates and mostly lower Ct values than the CDC N2. SARS-CoV-2 RNA was first detected at the first event when new reported cases were low. Increased positive detection rates preceded an increase in the number of newly reported cases and increased over time with the reported infection incidence. Wastewater surveillance (both positive rates and viral loads) showed strongest correlation with daily new COVID-19 cases at 22-24 days lag (Spearman's Rho = 0.85-1.00). Large WWTPs (serving 432,000-580,000 of the population) exhibited similar trends of viral loads and new cases to those from all 19 WWTPs, emphasizing that routine monitoring of the four large WWTPs could provide sufficient information for the city-scale dynamics. Higher sampling frequency at fewer sites, i.e., at the four representative WWTPs, is therefore suggested especially during the subsiding period of the outbreak to indicate the prevalence of COVID-19 infection, acting as an early warning of COVID-19 resurgence.

Inactivation of antibiotic resistant bacteria and their resistance genes in sewage by applying pulsed electric fields

We evaluated the suitability of pulsed electric field (PEF) technology as a new disinfection option in the sewage treatment plants (STPs) that can inactivate antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs). It was shown that PEF applied disinfection could inactivate not only vancomycin-resistant enterococci (VRE), but also vanA resistance gene. Cultivable VRE could be effectively inactivated by PEF applied disinfection, and were reduced to below the detection limit (log reduction value of VRE > 5 log). Although the vanA also showed a reduction of more than 4 log, it remained in the order of 10⁵ copies/mL, suggesting that ARGs are more difficult to be inactivated than ARB in PEF applied disinfection. Among parameters in each applying condition verified in this study, the initial voltage was found to be the most important for inactivation of ARB and ARGs. Furthermore, frequency was a parameter that affects the increase or decrease of the duration time, and it was suggested that the treatment time could be shortened by increasing the frequency. Our results strongly suggested that PEF applied disinfection may be a new disinfection technology option for STPs that contributes to the control of ARB and ARGs contamination in the aquatic environments.

Antibiotic residues in wastewaters from sewage treatment plants and pharmaceutical industries: Occurrence, removal and environmental impacts

Sewage treatment plants (STPs) and pharmaceutical manufactories (PMFs) are recognized as important reservoirs for aquatic pollution with antibiotics. Although the occurrence of multiple classes of antibiotics has been mostly reported for STPs and PMFs, knowledge on the effects of wastewater treatment processes on the removal of antibiotics is not well documented. In this study, wastewaters were collected from different treatment points of two STPs and two PMFs in eastern China. Thirty-seven antibiotics within the four classes of fluoroquinolones (FQs), macrolides (MACs), sulfonamides (SAs) and tetracyclines (TCs) were analyzed. Among the investigated antibiotics, 19-33 out of 37 target compounds were detected at least once in the STPs wastewaters ranging from low ng/L to approximately 12.7 μ/L. In the wastewater samples collected from PMFs, up to 34 antibiotics were present with detection frequencies up to 100%, showing generally higher concentrations (up to 19.0 μ/L) than those at the STPs. FQs and SAs were the dominant antibiotic families, which accounted for more than 90% of the total antibiotic concentration in the wastewaters. Moreover, the removal of antibiotics by anaerobic-anoxic-oxic (A²O), membrane bioreactor (MBR) and conventional activated sludge (CAS) systems was evaluated. The MBR system exhibited the best performance, mainly due to the processes of biodegradation and sorption during biological treatments. Notably, several SAs (SMP, SMZ) and FQs (CIN, ENO) antibiotics were consistently detected at concentration levels of μ/L in the effluent samples. The culturable antibiotic-resistance tests and risk assessment indicated that the antibiotic-contaminated effluents would facilitate the development of resistant bacteria and pose high toxicity to non-target organisms in the aquatic environment. Overall, the findings suggested an urgent need for improving the wastewater treatment technologies for simultaneous removal of different classes of antibiotics.

Occurrence and fate of antibiotics and heavy metals in sewage treatment plants and risk assessment of reclaimed water in Chengdu, China

Aim of this study was to provide an up-to-date assessment of the heavy metals and antibiotics in reclaimed water in Chengdu, China. 3 sewage treatment plants (STPs) and 1 constructed wetland (CW) were first taken as the research objects. The total concentration and reduction change rule of heavy metals and antibiotics in the process of reclaimed water production were investigated. The possible health risks to ecological environment and human body were evaluated. For the treatment process, the Cyclic Activated Sludge System (CASS) used in A sewage treatment plant (STP A) had the best removal effect for heavy metals. When the proportion of industrial wastewater in the influent was relatively high, the heavy metal pollution level was alert. Ofloxacin (OFX) and roxithromycin (ROX) were the most abundant antibiotics in reclaimed water. After being removed by the sewage treatment system, OFX concentrations changed, but several of them remained in reclaimed water. Negative removal of ROX occurred. This is because macrolides were wrapped in human feces, whose concentration increased as feces disperse and hydrolyze. Compared with CASS (20.02%) and Anaerobic-Anoxic-Oxic process (A²/O 34.16%), the average removal rate of antibiotics from the A²/O accompanied by Membrane Bio-Reactor (71.1%) and CW (54.95%) was higher. When the proportion of domestic sewage in wastewater was high, antibiotics in reclaimed water had higher ecological risk. OFX had the highest ecological risk for non-target aquatic organisms. It was assessed that the heavy metals and antibiotics studied did not pose a carcinogenic or non-carcinogenic risk to human health.

Evaluating environmental impact of STP effluents on receiving water in Beijing by the joint use of chemical analysis and biomonitoring

To evaluate the environmental impact of receiving water from the Qinghe River sewage treatment plant (STP) effluents in Beijing, we collected sediments and Bellamya aeruginosa (Up-site, Discharge-site, and Down-site) both in 2017 and 2018 and analyzed the samples via chemical analysis, biological responses and transcriptomics. In two years of data, our biological results showed that AChE activities presented different degrees of influence on B. aeruginosa captured at sampling points of the STP compared to control sites (P < 0.05). Additionally, indicators of the antioxidant system (e.g., SOD, CAT, GST, EROD activity) and MDA content were significantly increased in the whole tissue at the Up-site of the STP. Integration of the assessed biomarkers using the integrated biomarker response (IBR) index ranked the environmental impact at sites as Up-site > Discharge-site > Down-site. In terms of the transcriptome data, B. aeruginosa collected from the Discharge-site of the STP showed greater transcriptomic response than it did from all other sites. KEGG pathway analysis revealed that sewage significantly altered the expression of genes involved in xenobiotics by cytochrome P450, drug metabolism-cytochrome P450, glutathione metabolism, oxidative phosphorylation, citrate (TCA) cycle, glycolysis/gluconeogenesis, apoptotic and Parkinson's disease. The concentrations of 34 organic pollutants (17 PAHs, 10 PAEs, 7 EDCs) were measured. The chemical concentrations of pollutants decreased from Up-site to Down-site and were well correlated with enzyme activity, IBR, and transcriptomic results. Our results demonstrated that the combined use of chemical analysis, biological responses and transcriptome data is necessary to validate the efficacy of a battery of biomarkers chosen to detect environmental stress due to pollution.

Characterization of antibiotic resistance genes and bacterial community in selected municipal and industrial sewage treatment plants beside Poyang Lake

Sewage treatment plants (STPs) are significant reservoirs of antibiotic resistance genes (ARGs) and antibiotic-resistant bacteria (ARB). Municipal STPs (MSTPs) and industrial STPs (ISTPs) are the two most important STP types in cities. In this study, the ARGs, mobile genetic elements (MGEs), and bacterial communities of selected STPs, including two MSTPs and one ISTP, in the vicinity of Poyang Lake were comprehensively investigated through high-throughput qPCR and high-throughput Illumina sequencing. The results showed that the profiles of ARGs, MGEs and bacteria differed between the ISTP and the two MSTPs, most likely due to differences in influent water quality, such as the Pb that characterized in the ISTP's influent. The longer hydraulic retention times (HRTs) of the two MSTPs than of the ISTP may also have accounted for the different profiles. Thus, a prolonged HRT in the CASS process seems to allow a more extensive removal of ARGs and bacteria in ISTPs with similar treatment process. By providing comprehensive insights into the characteristics of ARGs, MGEs and the bacterial communities of the selected MSTPs and ISTP, our study provides a scientific basis for controlling the propagation and diffusion of ARGs and ARB in different types of STPs.

Occurrence of disinfection by-products in sewage treatment plants and the marine environment in Hong Kong

Disinfection byproducts (DBPs) are generated by disinfectants reacting with organic matters. Previous studies have focused on DBPs in drinking water, but they have not paid sufficient attention to DBPs in sewage treatment plants (STPs), where the sources and compositions of DBPs are much more complicated, and there is a likelihood of more toxic DBPs being formed. In this study, the occurrence of DBPs in six STPs in Hong Kong and the potential impact of the effluents from the STPs on the marine environment were investigated. In STPs, the mean concentrations of the total DBPs ranged from 1160 to 17,019 ng/L, 1562 to 20,795 ng/L, and 289 to 1037 ng/L in the influent, effluent, and seawater, respectively. Trihalomethanes, haloacetonitriles, and trihalophenols were the most commonly detected DBPs, whereas hexachloro-1,3-butadiene and halocarbazoles were not detected in the STPs and in the marine environment in Hong Kong. Secondary treatment efficiently removed DBPs and DBP precursors. Regarding disinfection techniques, UV irradiation showed little effect on the concentrations of DBPs, whereas sodium hypochlorite significantly elevated the levels of both traditional and emerging DBPs. The effluents from two selected STPs that use chlorination have an obvious impact on the marine environment. This work presents the potential sources of DBPs in sewage, the influence of the treatment processes and disinfection techniques employed in STPs on the removal/formation of DBPs, and the impact of the effluents from the STPs on the marine environment. This work also highlights the need for investigating the emerging DBPs generated in STPs and their related environmental concerns.

Volatile methylsiloxanes in sewage treatment plants in Saitama, Japan: Mass distribution and emissions

Wastewater, aeration gas, dewatered sludge, and incineration ash and flue gas (from dewatered sludge) were collected from 9 sewage treatment plants (STPs) located in Saitama Prefecture, Japan, and analyzed for seven cyclic and linear volatile methylsiloxanes (VMSs) namely, D3, D4, D5, D6, L3, L4, and L5. The mass loadings and distribution of VMSs in STPs were estimated based on measured concentrations in liquid, solid, and gaseous samples, including incinerated dewatered sludge. Mass loading of ΣVMS varied widely from 21 kg y^-1 to 3740 kg y^-1, depending on the volume of wastewater treated in each STP. Mass % of ΣVMS distributed in aeration gas was 15% and that in activated sludge was 78%. Approximately 6.6% of ΣVMS remained in the final effluent. Overall, partitioning onto the activated sludge was the dominant removal mechanism for D4, D5, and D6, whereas volatilization was also an important removal mechanism for D4. Incineration was effective to degrade VMSs in dewatered sludge, with a reduction rate of >99%. Activated carbon treatment removed >99% of VMSs from the aeration gas. In Saitama Prefecture, total emission of ΣVMS via STPs was estimated at 434 kg y^-1, 86 kg y^-1, and 0.065 kg y^-1, to aquatic, atmospheric, and terrestrial environments, respectively, which accounted for 83%, 17%, and 0.01% of the total environmental emissions. Our results indicate that majority of VMSs in dewatered sludge can be removed by incineration and emission of VMSs through incineration ash landfill is negligible.

Emission of primary microplastics in mainland China: Invisible but not negligible

Primary microplastics are mostly produced as part of the daily plastic product use. The emission process is often invisible but poses potential ecological hazards. Thus, primary microplastics deserve public attention. Due to China's huge population base and its rapid economic development, primary microplastics emissions are of both regional and global significance. This study is the first to establish the emission inventory of primary microplastics in mainland China. It was estimated that the primary microplastic waste from mainland China amounts to 737.29 Gg, and one-sixth of this amount entered the aquatic environment in 2015. The highest proportion of this waste was attributable to tire dust and synthetic fiber, accounting for 53.91% and 28.77% of the total respectively, in mainland China. The primary microplastics emissions mainly depend on the population, followed by the level of economic development. It was roughly estimated that 538 g of microplastics is produced by each person in China. At the grid scale, the spatial difference in the total primary microplastics emissions in mainland China primarily depends on the population density distribution and transportation network. We studied the entire life cycle of several sources of microplastics, from production to discharge into the aquatic environment. We suggested different control measures under different nodes. Increasing microplastics treatment in sewage treatment plants should be a short-term viable way to achieve some measure of reduction in their entry to the environment in mainland China. Our research can not only raise public awareness about primary microplastics, but can also guide the development of environmental policies to reduce plastic pollution.

Development and validation of a comprehensive solid-phase extraction method followed by LC-TOF/MS for the analysis of eighteen pharmaceuticals in influent and effluent of sewage treatment plants

The scarcity of data about the occurrence of pharmaceuticals in water bodies in Malaysia prompted us to develop a suitable analytical method to address this issue. We therefore developed a method based on solid-phase extraction combined with liquid chromatography-time of flight/mass spectrometry (SPE-LC-TOF/MS) for the analysis of sixteen prescribed and two nonprescribed pharmaceuticals that are potentially present in water samples. The levels of these pharmaceuticals, which were among the top 50 pharmaceuticals consumed in Malaysia during the period 2011-2014, in influent and effluent of five sewage treatment plants (STPs) in Bangi, Malaysia, were then analyzed using the developed method. All of the pharmaceuticals were separated chromatographically using a 5 μm, 2.1 mm × 250 mm C18 column at a flow rate of 0.3 mL/min. Limits of quantification (LOQs) were 0.3-8.2 ng/L, 6.5-89 ng/L, and 11.1-93.8 ng/L in deionized water (DIW), STP effluent, and STP influent, respectively, for most of the pharmaceuticals. Recoveries were 51-108%, 52-118%, and 80-107% from the STP influent, STP effluent, and DIW, respectively, for most of the pharmaceuticals. The matrix effect was also evaluated. The signals from carbamazepine, diclofenac sodium, and mefenamic acid were found to be completely suppressed in the STP influent. The signals from other compounds were found to be influenced by matrix effects more strongly in STP influent (enhancement or suppression of signal ≤180%) than in effluent (≤94%). The signal from prednisolone was greatly enhanced in the STP influent, indicating a matrix effect of -134%. Twelve pharmaceuticals were frequently detected in all five STPs, and caffeine, prazosin, and theophylline presented the highest concentrations among all the pharmaceuticals monitored: up to 7611, 550, and 319 ng/L in the STP influent, respectively. To the best of our knowledge, this is the first time that prazosin has been detected in a water matrix in Malaysia. Graphical abstract ᅟ.

Pharmaceutical concentration variability at sewage treatment plant outlets dominated by hydrology and other factors

A study was conducted in which the effluent at four small to medium sized sewage treatment plants (STP) in North Rhine-Westphalia, Germany was monitored for three pharmaceutical compounds (carbamazepine, diclofenac, metoprolol) over a period of four years. Grab sampling and auto sampling campaigns were accomplished with respect to various weather conditions in the catchment area. Flow volumes and hydraulic retention times (HRT) from various sampling dates which provide information on processes causing emission changes were additionally taken into account. Monitoring results showed that concentration scattering in the effluent is related to HRT in the sewage treatment plants. Dilution effects following rain events in the catchment area were analysed for the three investigated substances. Short-term emission changes explained by dilution only could be well determined by the mathematical relation between discharge and concentration, and for carbamazepine to be solely determined by the dilution effects at all HRTs. For metoprolol, a clear decrease in concentrations was observed at HRTs above 80 h, and a significant contribution of biodegradation was supported by independent biodegradation tests. For three out of the four STPs, a decrease in concentrations of diclofenac was observed at hydraulic retention times above 80 h, indicating removal, whereas the relationship between concentration and HRT of the other STP could be explained by dilution only. The study shows that emissions can vary with weather conditions, hampering the assessment of emissions and estimation of concentrations in surface waters from generic removal rates only. Furthermore, it illustrates the importance of HRT of rather stable substances in wastewater treatment.

Insufficient decontamination in Sewage treatment plants induce the risk of artificial selection of extended-spectrum β-lactamase producing Escherichia coli

Quantitative data about extended-spectrum beta-lactamase producing E. coli (ESBLEC) in the wastewaters are scarce, especially in developing countries. These data could be useful to raise awareness about the potential risk of spreading ESBLEC strains in the community. Water samples were collected weekly over a 10-week period, from one urban sewage treatment plant (STP), one rural STP and one hospital complex's wastewater (HWW) in Turkey. Mean E. coli and ESBLEC loads were determined for each sampling point. For the 580 ESBLEC isolated, antimicrobial resistance profiles, phylogenetic grouping, presence of common beta-lactamese-typesand integrons were studied using PCR. The mean ESBLEC ratio was accounted for 0.58%, 0,12%, 1.53% of the total E. coli in urban, rural untreated wastewater and HWW, respectively. These values were higher for the outlets. The mean number of different antimicrobial classes to which the strains were resistant was highest in urban STP (4.0± 1.6). The antimicrobial resistance ratios of ESBLEC strains isolated from HWW were observed to be in between those of urban and rural STPs. The most common phylogenetic group was C composing (29.7%) and the most susceptible strains belonged to phylogroup B1. Wastewater treatments without sufficient decontamination, resulting in artificial selection of ESBLEC might lead to public health risk as these strains reach communities through environment. To avoid such risks and protect the human health as well as the environment, well-established decontamination measures imposing barriers against this artificial selection should be implemented.

Mass loading and removal of benzotriazoles, benzothiazoles, benzophenones, and bisphenols in Indian sewage treatment plants

Little is known about the occurrence of emerging environmental contaminants, such as benzotriazoles (BTRs), benzothiazoles (BTHs), benzophenones (BzPs), and bisphenol analogues (BPs) in India. In this study, we determined the occurrence and removal of BTRs, BTHs, BzPs, and BPs in five Indian sewage treatment plants (STPs). The respective measured mean concentrations (N = 5) in influents and effluents were 370 and 57.4 ng L^-1 for BTRs, 50800 and 20200 ng L^-1 for BTHs, 351 and 163 ng L^-1 for BzPs, and 98.0 and 9.6 ng L^-1 for BPs. Among the target chemicals analyzed, BTHs were found at elevated levels, and the measured levels were some of the highest ever reported in the literature. The mean concentrations (N = 5) of BTRs, BTHs, BzPs, and BPs in sludge were 44.2, 51200, 124, and 200 ng g^-1 dry wt, respectively. The removal efficiencies for BTRs, BTHs, BzPs, and BPs ranged as follows: 54.2-85.6%, 23.4-85.0%, 51.8-71%, and 76.0-97.0%, respectively, and were comparable to those reported for other countries. Elevated concentrations of BTHs in Indian STPs can be related to consumption of these chemicals in a wide range of products including paper, textile and rubber materials.

Profiles and removal efficiency of polycyclic aromatic hydrocarbons by two different types of sewage treatment plants in Hong Kong

Sewage discharge could be a major source of polycyclic aromatic hydrocarbons (PAHs) in the coastal waters. Stonecutters Island and Shatin Sewage Treatment Works (SCISTW and STSTW) in Hong Kong, adopted chemically enhanced primary treatment and biological treatment, respectively. This study aimed at (1) determining the removal efficiencies of PAHs, (2) comparing the capabilities in removing PAHs, and (3) characterizing the profile of each individual PAHs, in the two sewage treatment plants (STPs). Quantification of 16 PAHs was conducted by a Gas Chromatography. The concentrations of total PAHs decreased gradually along the treatment processes (from 301±255 and 307±217ng/L to 14.9±12.1 and 63.3±54.1ng/L in STSTW and SCISTW, respectively). It was noted that STSTW was more capable in removing total PAHs than SCISTW with average total removal efficiency 94.4%±4.12% vs. 79.2%±7.48% (p<0.05). The removal of PAHs was probably due to sorption in particular matter, confirmed by the higher distribution coefficient of individual and total PAHs in solid samples (dewatered sludge contained 92.5% and 74.7% of total PAHs in SCISTW and STSTW, respectively) than liquid samples (final effluent-total contained 7.53% and 25.3% of total PAHs in STSTW and SCISTW, respectively). Despite the impressive capability of STSTW and SCISTW in removing PAHs, there was still a considerable amount of total PAHs (1.85 and 39.3kg/year, respectively for the two STPs) being discharged into Hong Kong coastal waters, which would be an environmental concern.

Vitellogenin induction and reduced fecundity in zebrafish exposed to effluents from the City of Bulawayo, Zimbabwe

Industrial and municipal effluents regularly pollute water bodies and cause various toxic effects to aquatic life. Because of the diverse nature of industrial processes and domestic products, urban effluents are often tainted with various anthropogenic endocrine disrupting chemicals that may interfere with the reproductive physiology of aquatic fauna. In this study, we tested effluents from the City of Bulawayo for the presence of estrogenic endocrine disrupting chemicals and their effects on fish gonads and fecundity. Effluents were collected from two sewage treatment plants (STPs), which receive largest volume of industrial effluents from the City, and from a textile factory. Male and female zebrafish (Danio rerio) were exposed to effluents and analyzed for vitellogenin induction, gonad alterations, and fertility. Male zebrafish exposed to effluent from Thorngrove STP had significantly higher (p ≤ 0.05) vitellogenin compared to control. Textile effluent caused adverse gonad alterations such as oocyte atresia (females) and increased proportion of spermatogonia (males) which could lead to reduced fertility. Textile effluent (5% v/v) and Thorngrove effluent also caused a decline in fertilization success of breeding groups of zebrafish. The results of this study show the potential effects of effluent pollution and the occurrence of EDCs in developing countries. This underscores the need to effectively prevent pollution of environmental water bodies from industrial and municipal sewage treatment plant effluents. We recommend a follow-up study to monitor the effects of the effluents on feral fish in effluent polluted downstream dams of Bulawayo.

A comprehensive survey on the occurrence and fate of nitrosamines in sewage treatment plants and water environment

A comprehensive examination of nitrosamines was conducted in a water system, which included sewage treatment plants (STPs), river water, and seawater to understand their characteristic occurrence and fates in whole real water system. The concentrations of nitrosamines were highest in the STP influent (1440-29,100ng/L), followed by the river water (26.0-5180ng/L), the STP effluent (9.58-310ng/L), and seawater (44.2-155ng/L). The samples were especially affected by proximity to the industrial zone and the samples collected near industrial complex had much higher levels than others with different distribution patterns. In the STPs, nitrosamines were mostly eliminated during biological treatment processes (86.7-95.0%), while they were formed through chlorination processes (-59.6 to -27.7%), which is consistent with previous surveys. The primary clarifier showed insignificant elimination tendencies (5.6-28.2%). Although removal by ultraviolet light was effective (73.2-94.1%), more surveys may be needed because of conflicting results in other studies. Among water quality parameters, nitrosamines in waste water were linked with organic carbon and nitrogen levels.

Measurement techniques for assessing the olfactory impact of municipal sewage treatment plants

The study presents information about the measurement techniques used for the assessment of air quality in terms of the olfactory intensity resulting from the operation of municipal sewage treatment plants. Advantages and disadvantages of the measurement techniques used are presented. Sources of malodourous substance emission from sewage treatment plants were described, and the malodourous substances emitted were characterised. Trends in development of analysis and monitoring of the malodourous substances in the air were also presented.

Tracking multiple modes of endocrine activity in Australia's largest inland sewage treatment plant and effluent- receiving environment using a panel of in vitro bioassays

Estrogenicity of sewage effluents, and related ecotoxicological effects in effluent-receiving environments, have been widely reported over the last 2 decades. However, relatively little attention has been given to other endocrine pathways that may be similarly disrupted by a growing list of contaminants of concern. Furthermore, the Australian evidence base is limited compared with those of Europe and North America. During a low dilution period in summer, the authors investigated multiple endocrine potencies in Australia's largest inland sewage treatment plant (STP) and the Lower Molonglo/Upper Murrumbidgee effluent-receiving environment. This STP receives 900 L/s of mostly domestic wastewater from a population of 350 000, and contributes a high proportion of total flow in the lower catchment during dry periods. A panel of in vitro receptor-driven transactivation assays were used to detect (anti)estrogenic, (anti) androgenic, (anti)progestagenic, glucocorticoid, and peroxisome-proliferator activity at various stages of the sewage treatment process. Total estrogenic and (anti)androgenic potency was removed after primary and/or secondary treatment; however, total removal efficiency for glucocorticoid potency was poorer (53-66%), and progestagenic potency was found to increase along the treatment train. Estrogenicity was detected in surface waters and bed sediments upstream and downstream of the effluent outfall, at maximum levels 10 times lower than low-hazard thresholds. Glucocorticoid and progestagenic activity were found to persist to 4 km downstream of the effluent outfall, suggesting that future research is needed on these endocrine-disrupting chemical categories in effluent-receiving systems.

Efficiency of hepatitis A virus removal in six sewage treatment plants from central Tunisia

The efficiency of six Tunisian sewage treatment plants (STP) for the removal of hepatitis A virus (HAV) from wastewater was analysed in order to evaluate the potential risk for human health linked to reuse or discharge of treated wastewater into the environment. The STP utilize different biological wastewater treatments including primary treatment, which involves the physical removal of organic and inorganic solids, and secondary treatment that involves different processes, such as activated sludge or lagoon. Quantitative real-time reverse transcription polymerase chain reaction (RT-PCR) and conventional RT-PCR were used for the analysis of the 325 wastewater samples (163 raw and 162 treated) obtained. Results revealed highest contamination in west-central of Tunisia in raw wastewater with 62.96 % of samples positive for HAV and predominance during winter and autumn, whereas east-central region showed 50.62 % of positive samples with high prevalence from winter through summer. The quantitative analysis revealed a range between 4.29 × 10(1) and 1.24 × 10(5) RNA copies/mL in treated wastewater, showing clearly the inefficiency for total removal of HAV regardless of the treatment method used. The vast majority of HAV sequences belonged to the sub-genotype IA, except one that was assigned to sub-genotype IB.

Efficiency of an emissions payment system for nitrogen in sewage treatment plants - a case study

An emissions payment system for nitrogen in Swedish sewage treatment plants (STPs) was evaluated using a semi-empirical approach. The system was based on a tariff levied on each unit of nitrogen emitted by STPs, and profitable measures to reduce nitrogen emissions were identified for twenty municipal STPs. This was done through direct involvement with the plant personnel and the results were scaled up to cover all treatment plants larger than 2000 person equivalents in the Swedish tributary areas of the Kattegat and the Baltic Proper. The sum of costs and nitrogen reductions were compared with an assumed command-and-control regulation requiring all STPs to obtain 80% total nitrogen reduction in their effluents. Costs for the latter case were estimated using a database containing standard estimates for reduction costs by six specified measures. For both cases a total reduction target of 3000 tonnes of nitrogen was set. We did not find that the emissions payment system was more efficient in terms of total reduction costs, although some practical and administrative advantages could be identified. Our results emphasize the need to evaluate the performance of policy instruments on a case-by-case basis since the theoretical efficiency is not always reflected in practice.