Major Wastewater Treatment Plant Research Articles

Ecological risk assessment associated to the removal of endocrine-disrupting parabens and benzophenone-4 in wastewater treatment

The occurrence of four widely used and endocrine disrupting parabens (PBs) (methylparaben, propylparaben, butylparaben and benzylparaben) and a polar UV filter (benzophenone-4) were determined in influent and effluent wastewater from the 19 major wastewater treatment plants (WWTPs) of Catalonia, Spain. For their analysis an on-line solid-phase extraction-liquid chromatography–tandem mass spectrometry (SPE-HPLC–MS/MS) method was developed and validated. Laboratory analysis revealed high levels for both PBs and BP4, with maximum concentrations of 5700ngL−1 and 1806ngL−1, respectively, in influent samples, and 137ngL−1 and 1080ngL−1, respectively in effluent wastewaters. Removal rates (RE%) for the target compounds in each WWTPs were calculated. RE% for parabens were almost 100%, whereas for BP4 values where in the range 5–91%. The half-life time (t1/2), hydraulic retention time (HRT), and annual mass load (ML) for each facility was estimated. Results indicated that there was no clear influence of HRT on the RE% of BP4. MLs for BP4 were in the range 0.9–110.1kgy−1, with the highest values in the most populated areas. Finally, a risk assessment, estimated in terms of hazard quotients (HQs), was carried out for aquatic biota. HQs for the target compounds in effluent wastewaters indicated a negligible effect, whereas for some influent wastewaters’ HQs pointed out that some species are at risk.

Bioaccumulation of human pharmaceuticals in fish across habitats of a tidally influenced urban bayou.

Though pharmaceuticals and other contaminants of emerging concern are increasingly observed in inland water bodies, the occurrence and bioaccumulation of pharmaceuticals in estuaries and coastal ecosystems are poorly understood. In the present study, bioaccumulation of select pharmaceuticals and other contaminants of emerging concern was examined in fish from Buffalo Bayou, a tidally influenced urban ecosystem that receives effluent from a major (∼200 million gallons per day) municipal wastewater treatment plant in Houston, Texas, USA. Using isotope dilution liquid chromatography-tandem mass spectrometry, various target analytes were observed in effluent, surface water, and multiple fish species. The trophic position of each species was determined using stable isotope analysis. Fish tissue levels of diphenhydramine, which represented the only pharmaceutical detected in all fish species, did not significantly differ between freshwater and marine fish predominantly inhabiting benthic habitats; however, saltwater fish with pelagic habitat preferences significantly accumulated diphenhydramine to the highest levels observed in the present study. Consistent with previous observations from an effluent-dependent freshwater river, diphenhydramine did not display trophic magnification, which suggests site-specific, pH-influenced inhalational uptake to a greater extent than dietary exposure in this tidally influenced urban ecosystem. The findings highlight the importance of understanding differential bioaccumulation and risks of ionizable contaminants of emerging concern in habitats of urbanizing coastal systems.

Estrogenic activity of wastewater, bottled waters and tap water in Finland as assessed by a yeast bio-reporter assay.

Environmental pollutants appearing in wastewater, bottled mineral water, tap water, and bottled drinking water are potential, but yet poorly characterized, sources of human exposure to endocrine disrupting chemicals globally. Here, we investigated the current situation in the most densely populated region in Finland. Influent and effluent bi-monthly samples from a major wastewater treatment plant in Helsinki were obtained over a preceding 2-year period at two time-points (in 2011 and 2014). Equivalent samples from a household water purification plant (located in the same region) were also analyzed, together with various brands of bottled still and mineral water as well as tap water from residential buildings. Samples were obtained in one liter sterile containers, extracted by solid-phase extraction method, and their estrogenic potential determined by a yeast bioluminescent assay. The estrogenic activities of influent samples from the wastewater treatment plant in Helsinki were generally low (from less than limit of detection to 0.7 ng/L estrogen equivalent quantities (EEQ)), except in March and August 2011, when relatively high levels (14.0 and 7.8 ng/L EEQ, respectively) were obtained. Meanwhile, no estrogenic activity was recorded in any of the treated effluent samples from the wastewater treatment plant, influent and effluent samples from the drinking water plant, as well as tap water, bottled still, and mineral waters. These findings indicate that the purification method applied in Helsinki wastewater treatment plant, activated sludge with mechanical, chemical and biological purification steps, is effective in reducing estrogenic activity, and that tap or bottled waters are not a significant source of these compounds to the population in this region.

Evaluation of Watershed Susceptibility to Contaminants of Emerging Concern

Contaminants of emerging concern (CECs) are raising public awareness because of their potential effect on aquatic ecosystems and public health. For this study, the authors applied spatial analyses to four selected US watersheds to identify critical areas susceptible to CECs and used watershed characteristics (i.e., potential source distribution, land use, climatic and hydrologic conditions) to prioritize the types of CECs. The results identified sub‐basins where major wastewater treatment plants are located as critical areas for potential CEC point source pollution in general. Sub‐basins containing intensive agricultural activities with high precipitation greatly contributed to CEC pollution, especially during wet‐weather periods. The rank of prioritized prescribed pharmaceutical groups was similar for most watersheds because of the association between pharmaceutical groups and population demographics. Prioritized pesticide types were dependent on the type and areas of crops and urban yards in each watershed. This study demonstrates the utility of using spatial analysis for effectively assessing CECs in watersheds, which is important for the implementation of monitoring and management strategies.

Endocrine disrupting alkylphenolic chemicals and other contaminants in wastewater treatment plant effluents, urban streams, and fish in the Great Lakes and Upper Mississippi River Regions

Urban streams are an integral part of the municipal water cycle and provide a point of discharge for wastewater treatment plant (WWTP) effluents, allowing additional attenuation through dilution and transformation processes, as well as a conduit for transporting contaminants to downstream water supplies. Domestic and commercial activities dispose of wastes down-the-drain, resulting in wastewater containing complex chemical mixtures that are only partially removed during treatment. A key issue associated with WWTP effluent discharge into streams is the potential to cause endocrine disruption in fish. This study provides a long-term (1999–2009) evaluation of the occurrence of alkylphenolic endocrine disrupting chemicals (EDCs) and other contaminants discharged from WWTPs into streams in the Great Lakes and Upper Mississippi River Regions (Indiana, Illinois, Michigan, Minnesota, and Ohio). The Greater Metropolitan Chicago Area Waterways, Illinois, were evaluated to determine contaminant concentrations in the major WWTP effluents and receiving streams, and assess the behavior of EDCs from their sources within the sewer collection system, through the major treatment unit processes at a WWTP, to their persistence and transport in the receiving stream. Water samples were analyzed for alkylphenolic EDCs and other contaminants, including 4-nonylphenol (NP), 4-nonylphenolpolyethoxylates (NPEO), 4-nonylphenolethoxycarboxylic acids (NPEC), 4-tert-octylphenol (OP), 4-tert-octylphenolpolyethoxylates (OPEO), bisphenol A, triclosan, ethylenediaminetetraacetic acid (EDTA), and trace elements. All of the compounds were detected in all of the WWTP effluents, with EDTA and NPEC having the greatest concentrations. The compounds also were detected in the WWTP effluent dominated rivers. Multiple fish species were collected from river and lake sites and analyzed for NP, NPEO, NPEC, OP, and OPEO. Whole-body fish tissue analysis indicated widespread occurrence of alkylphenolic compounds, with the highest concentrations occurring in streams with the greatest WWTP effluent content. Biomarkers of endocrine disruption in the fish indicated long-term exposure to estrogenic chemicals in the wastewater impacted urban waterways.

Modelling the fate of nitrite in an urbanized river using experimentally obtained nitrifier growth parameters

Maintaining low nitrite concentrations in aquatic systems is a major issue for stakeholders due to nitrite's high toxicity for living species. This study reports on a cost-effective and realistic approach to study nitrite dynamics and improve its modelling in human-impacted river systems. The implementation of different nitrifying biomasses to model riverine communities and waste water treatment plant (WWTP)-related communities enabled us to assess the impact of a major WWTP effluent on in-river nitrification dynamics. The optimal kinetic parameters and biomasses of the different nitrifying communities were determined and validated by coupling laboratory experiments and modelling. This approach was carried out in the Seine River, as an example of a large human-impacted river with high nitrite concentrations. The simulation of nitrite fate was performed at a high spatial and temporal resolution (Δt = 10 min, dx¯ = 500 m) including water and sediment layers along a 220 km stretch of the Seine River for a 6-year period (2007–2012). The model outputs were in good agreement with the peak of nitrite downstream the WWTP as well as its slow decrease towards the estuary. Nitrite persistence between the WWTP and the estuary was mostly explained by similar production and consumption rates of nitrite in both water and sediment layers. The sediment layer constituted a significant source of nitrite, especially during high river discharges (0.1–0.4 mgN h−1 m−2). This points out how essential it is to represent the benthic layer in river water quality models, since it can constitute a source of nitrite to the water-column. As a consequence of anthropogenic emissions and in-river processes, nitrite fluxes to the estuary were significant and varied from 4.1 to 5.5 TN d−1 in low and high water discharge conditions, respectively, over the 2007–2012 period. This study provides a methodology that can be applied to any anthropized river to realistically parametrize autochthonous and WWTP-related nitrifier communities and simulate nitrite dynamics. Based on simulation analysis, it is shown that high spatio-temporal resolution hydro-ecological models are efficient to 1) estimate water quality criteria and 2) forecast the effect of future management strategies. Process-based simulations constitute essential tools to complete our understanding of nutrient cycling, and to decrease monitoring costs in the context of water quality and eutrophication management in river ecosystems.

Pushing the Limit on Energy Efficiency for a Major Wastewater Treatment Plant Expansion Design

Pushing the Limit on Energy Efficiency for a Major Wastewater Treatment Plant Expansion Design

Impact of hydro-sedimentary processes on the dynamics of soluble reactive phosphorus in the Seine River

This paper focuses on soluble reactive phosphorus (SRP) dynamics along a 225 km stretch of the Seine River, including the Paris urban area, for the 2007–2011 period. The impact of hydro-sedimentary processes on SRP concentrations and fluxes is estimated under various hydrological conditions. Sorption interaction parameters between SRP and suspended matter are experimentally determined on river water samples and are included in a hydro-ecological model. Simulated concentrations are compared to weekly measurements at 11 monitoring stations. The introduction of sorption in the model reduces the root mean square error of simulated SRP concentrations by 20 % and allows the simulation of particulate inorganic P (PIP) accumulation in the system. With these ameliorations, the model constitutes a reliable management tool, which is compatible with the requirements of new regulations as the European Water Framework Directive. P mass balances are assessed upstream and downstream the major waste water treatment plant of the Paris urban area. P fluxes in the system are mainly driven by hydrological conditions and sediment-related processes. While SRP is the predominant P form during low flow, PIP accounts for more than 70 % of the total P during high flow. Moreover, SRP sorption fluxes are of the same order of magnitude as biotic fluxes affecting SRP concentrations. According to the model, and based on all the available data, 75 % of the SRP release by the river bed sediments occurs during high flow periods, and PIP exchanges at the sediment–water interface are more than 4 times higher during high flow periods than during low flow periods.

A multi-level biological approach to evaluate impacts of a major municipal effluent in wild St. Lawrence River yellow perch (Perca flavescens)

The development of integrated ecotoxicological approaches is of great interest in the investigation of global concerns such as impacts of municipal wastewater effluents on aquatic ecosystems. The objective of this study was to investigate the effects of a major wastewater municipal effluent on fish using a multi-level biological approach, from gene transcription and enzyme activities to histological changes. Yellow perch (Perca flavescens) were selected based on their wide distribution, their commercial and recreational importance, and the availability of a customized microarray. Yellow perch were sampled upstream of a major municipal wastewater treatment plant (WWTP) and 4km and 10km downstream from its point of discharge in the St. Lawrence River (Quebec, Canada). Concentrations of perfluoroalkyl substances (PFASs), polybrominated diphenyl ethers (PBDEs) and metals/trace elements in whole body homogenates were comparable to those from other industrialized regions of the world. Genomic results indicated that the transcription level of 177 genes was significantly different (p<0.024) between exposed and non-exposed fish. Among these genes, 38 were found to be differentially transcribed at both downstream sites. Impacted genes were associated with biological processes and molecular functions such as immunity, detoxification, lipid metabolism/energy homeostasis (e.g., peroxisome proliferation), and retinol metabolism suggesting impact of WWTP on these systems. Moreover, antioxidant enzyme activities were more elevated in perch collected at the 4km site. Biomarkers of lipid metabolism, biosynthetic activity, and aerobic capacities were significantly lower (p<0.05) in fish residing near the outfall of the effluent. Histological examination of the liver indicated no differences between sites. Correlations between PFAS, PBDE, and metal/trace element tissue concentrations and markers of peroxisomal proliferation, oxidative stress, and retinoid metabolism were found at the gene and cellular levels. Present results suggest that relating transcriptomic analyses to phenotypic responses is important to better understand impacts of environmental contamination on wild fish populations.

Spatial Variability in Nutrient Transport by HUC 8, State, and Subbasin Based on Mississippi/Atchafalaya River Basin SPARROW Models

Nitrogen (N) and phosphorus (P) loading from the Mississippi/Atchafalaya River Basin (MARB) has been linked to hypoxia in the Gulf of Mexico. With geospatial datasets for 2002, including inputs from wastewater treatment plants (WWTPs), and monitored loads throughout the MARB, SPAtially Referenced Regression On Watershed attributes (SPARROW) watershed models were constructed specifically for the MARB, which reduced simulation errors from previous models. Based on these models, N loads/yields were highest from the central part (centered over Iowa and Indiana) of the MARB (Corn Belt), and the highest P yields were scattered throughout the MARB. Spatial differences in yields from previous studies resulted from different descriptions of the dominant sources (N yields are highest with crop-oriented agriculture and P yields are highest with crop and animal agriculture and major WWTPs) and different descriptions of downstream transport. Delivered loads/yields from the MARB SPARROW models are used to rank subbasins, states, and eight-digit Hydrologic Unit Code basins (HUC8s) by N and P contributions and then rankings are compared with those from other studies. Changes in delivered yields result in an average absolute change of 1.3 (N) and 1.9 (P) places in state ranking and 41 (N) and 69 (P) places in HUC8 ranking from those made with previous national-scale SPARROW models. This information may help managers decide where efforts could have the largest effects (highest ranked areas) and thus reduce hypoxia in the Gulf of Mexico.

Necessary driving forces for infrastructure sustainability

The forces and complex interactions that hinder and promote the application of sustainable infrastructures are discussed along with changes that are needed in our economic-mindset for evaluating project costs. Some existing sustainable projects result from favourable economics. However, many fall in the trash basket as a result of so-called unfavourable economics. One of the key driving forces for engineering sustainability is innovation, and regulations have historically been the driving force for innovations. Recently formulated effluent standards for a major municipal wastewater treatment plant (300 MGD) are pushing the envelope by making the effluent a recoverable resource. These costs have a major impact on service fees and force the development of innovations in wastewater treatment and the handling of combined sewer overflows (CSO). Economic, social and design changes are recommended for wastewater treatment facilities to support sustainability in private and governmental infrastructure programmes.

Design and Implementation of Intelligent Control System for Industrial Sewage Treatment Aeration Quantity

Due to the characteristics of dissolved oxygen process, such as non-linear and time delay, the traditional control methods are not very ideal for the aeration quantity assignment in the major domestic wastewater treatment plants. An intelligent system that controls the aeration quantity of the wastewater treatment of biochemistry pools is adopted, which the feedback control and the intelligence model are used to keep the balance of aeration. Meanwhile, according to the concentration of dissolved oxygen, the rotational speed of the air blower is adjusted for the sake of saving energy. This control system has been realized by Schneider Premium TSX P57 PLC system and the results show that the system is stable and reliable.

Analysis of cocaine and nicotine metabolites in wastewater by liquid chromatography–tandem mass spectrometry. Cross abuse index patterns on a major community

A method based on sample preparation by solid phase extraction and analysis by liquid chromatography and mass spectrometry was validated and used for simultaneous analysis of cocaine, benzoylecgonine and cotinine in samples collected at the major wastewater treatment plant in the city of Lisbon. The aim was to estimate the consumption of both cocaine and nicotine in this community and establish an index involving both drugs supported by the relevance of nicotine as a significant anthropogenic marker. The study was made on two different weekdays during a month in order to evaluate patterns of consumption outside weekends. Cocaine and nicotine ingestion levels were back-calculated and expressed as mass of pure drugs consumed per day and per 1000 inhabitants (mean: 0.604g and 5.860g respectively). Cocaine was also expressed on the basis of local drug purity levels (33.7%) with a corresponding increase on dose assessments, and community drug abuse profiles. The authors sustain that this approach should always be included in drug studies of this kind allowing a better drug abuse assessment. No significant different patterns of consumption were obtained during the working days studied with the exception of one case coincident with a national holiday that showed an increased typical profile found on other non-working day studies, namely weekends. A fairly significant relationship was found between nicotine and cocaine consumption that should be further evaluated in future studies. Pharmacokinetic considerations were made and proposed for cocaine assessment based on the impact on back calculations after common simultaneous consumption of cocaine and ethanol.

Trace metal speciation at the sediment–water interface of Vidy Bay: influence of contrasting sediment characteristics

Trace metal analysis and speciation were performed at the sediment–water interface of Vidy Bay (Lake Geneva, Switzerland). This bay is impacted by hazardous compounds released via the sewage effluent of a major wastewater treatment plant (WWTP). Sediment cores and overlying water were sampled simultaneously at 12 sites characterized by contrasting sediment surface characteristics (color, methanogenic activity, bacterial mat) using corers deployed from a MIR submarine or research boat. The concentrations of trace metals in particulate form in the sediment and dissolved in the interstitial water, as well as the particulate, colloidal and dynamic fractions of trace metals in the overlying water were determined by combining an in situ and laboratory multi-method analytical approach. The results indicate differences in trace metal speciation in the sediment and overlying water at the 12 investigated sites. The observed differences were found to be more correlated to bacterial community, abundance, type and activity than to distance from the WWTP sewage outlet.

A survey of emerging contaminants in the estuarine receiving environment around Auckland, New Zealand

Increasing urbanisation in the future will put mounting stresses on the receiving environments around those urban centres due to increased sedimentation and contaminant runoff. Emerging contaminants (ECs) are an extensive array of chemicals and many are not under regulatory action. Within New Zealand likely future pressures from ECs will be in both urban centres and rural areas due to intensive agriculture, although at present there is a lack of information on the state of the environment in both sectors. This study was initiated to gauge the distribution of ECs in the urban environment by measuring concentrations of flame retardants, plasticisers, alkylphenols, herbicides and pesticides, steroid oestrogens, pharmaceuticals and heavy metals in sediment from 13 estuarine sites around Auckland, New Zealand's biggest city. Total polybrominated diphenyl ether (PBDE) flame retardant concentrations (7ΣPBDE) ranged from 0.55 to 573ng/g (dw). The phthalate plasticiser di(2-ethylhexyl)phthalate (DEHP) was measured at up to 11,500ng/g from one site. Nonylphenol (NP) was found at up to 32,000ng/g at one site adjacent to the city's major wastewater treatment plant (WWTP). However, median concentrations of NP were 153ng/g, suggesting this site was not representative of the region. Nonylphenol mono- and di-ethoxylates (NPEO1,2) had highest concentrations (1600ng/g) at a marina. Highest glyphosate concentrations (up to 950ng/g) were observed at residential sites. Steroid oestrogens were detected at extremely low concentrations (maximum 2.2ng/g), while all other pesticides or herbicides were not detected at any sites. Multi-residue analysis of 46 pharmaceuticals showed presence of 21 compounds at one or more sites, with average concentrations ranging from 0.16 to 7.66ng/g. Generally, environmental concentrations of ECs were similar to those reported world-wide. However, comparisons for pharmaceuticals were problematic, due to very few studies on pharmaceutical concentrations in estuarine sediments, with most focussed on sewage and stream water phases.

Occurrence and degree of intersex (testis–ova) in darters (Etheostoma SPP.) across an urban gradient in the Grand River, Ontario, Canada

The variability and extent of the intersex condition (oocytes in testes, or testis-ova) was documented in fish along an urban gradient in the Grand River, Ontario, Canada, that included major wastewater treatment plant outfalls. A method for rapid enumeration of testis-ova was developed and applied that increased the capacity to quantify intersex prevalence and severity. Male rainbow darters (Etheostoma caeruleum) sampled downstream of the first major wastewater outfall (Waterloo) had a significant increase, relative to 4 upstream reference sites, in the mean proportion of fish with at least 1 testis-oocyte per lobe of testes (9-20% proportion with ≤ 1 testis-oocyte/lobe vs 32-53% and >1.4 testis-oocyte/lobe). A much higher mean incidence of intersex proportion and degree was observed immediately downstream of the second wastewater outfall (Kitchener; 73-100% and 8-70 testis-oocyte/lobe); but only 6.3 km downstream of the Kitchener outfall, the occurrence of intersex dropped to those of the reference sites. In contrast, downstream of a tertiary treated wastewater outfall on a small tributary, intersex was similar to reference sites. Estrogenicity, measured using a yeast estrogen screen, followed a similar pattern, increasing from 0.81 ± 0.02 ng/L 17b-estradiol equivalents (EEq) (Guelph), to 4.32 ± 0.07 ng/L (Waterloo), and 16.99 ± 0.40 ng/L (Kitchener). Female rainbow darter downstream of the Kitchener outfall showed significant decreases in gonadosomatic index and liver somatic index, and increases in condition factor (k) relative to corresponding reference sites. The prevalence of intersex and alterations in somatic indices suggest that exposure to municipal wastewater effluent discharges can impact endocrine function, energy use, and energy storage in wild fish.

Sublethal effects of the flame retardant intermediate hexachlorocyclopentadiene (HCCPD) on the gene transcription and protein activity of Daphnia magna

Hexachlorocyclopentadiene (HCCPD) is a chlorinated chemical of high production volume used as an intermediate in the production of flame retardants. HCCPD may be released to the environment during production, use, and as a result of product degradation. The objectives of this study were to evaluate sublethal effects of HCCPD exposure to Daphnia magna at environmentally relevant concentrations (0.0138–13.8μg/L) using genomic tools (microarray and qPCR), enzyme activities, and life-history endpoints (survival, reproduction, and growth). In chronic exposures, no differences were observed in life-history endpoints (survival, time of first brood, time of first molt, molt frequency, number of neonates, and body length) between exposed organisms and controls. Microarray analyses indicated significant differential genomic transcription for 46 genes (p-value≤0.05 and fold-change>2). Five identified genes were related to metabolic functions. Enzyme activities of α-amylase and trypsin, selected based on transcriptional responses, were evaluated in D. magna. Although trypsin activity was similar between treatments and controls, the activity of α-amylase significantly decreased with increasing HCCPD concentrations. On the chemical level, instability of HCCPD was observed in spiked culture media, most probably due to photolysis and biodegradation. HCCPD was not detected in surface water samples collected upstream and at the point of discharge of a major wastewater treatment plant effluent. Environmentally, rapid degradation of HCCPD could be outdone by its continuous release into aquatic ecosystems in specific areas of concern (e.g., vicinity of industries and hazardous sites). Toxicity results from this study highlight the use of genomics in the identification of biomarkers and help advance the science, and potential use, of multi-level biological approaches for environmental risk assessment.

Levels, compositions, and inventory of polybrominated diphenyl ethers in sewage sludge of Guangdong Province, South China

Polybrominated diphenyl ethers (PBDEs) were measured in sewage sludge samples collected from major wastewater treatment plants in Guangdong Province, South China. Concentrations of ∑39PBDE (all 39 compounds including tri- to hepta- PBDE congeners except for BDE-209) ranged from 3.6 to 428 ng/g dw with a mean value of 67.4 ng/g dw and a median value of 25.9 ng/g dw, and those of BDE-209 ranged from 9.9 to 5,010 ng/g dw (mean 1,024 ng/g dw and median 824 ng/g dw). The PBDE mixtures detected were mainly comprised of penta-, octa-, and deca-BDEs, with deca-BDE as the dominant constituent. The most abundant congeners, excluding BDE-209, were BDE-47, BDE-99, and BDE-183. Good correlations were found among the concentrations of BDE-47, BDE-99, BDE-100, BDE-138, and BDE-154 (r>0.8). However, poor correlations were found between the concentrations of BDE-209 and all other congeners (r<0.3). This fact suggests that most tri- to hepta-BDEs detected did not originate from decomposition of deca-BDE. The estimated annual emission of ∑allPBDEs, ∑39PBDEs, penta-BDE, octa-BDE, and deca-BDE to the Pearl River Delta environment (PRD), based on the sludge samples analyzed, amounts to 232, 20.2, 5.5, 1.7, and 212 kg per year, implicating sewage sludge as a significant source of PBDEs to the PRD environment.

Multi-Level Approach for the Integrated Assessment of Polar Organic Micropollutants in an International Lake Catchment: The Example of Lake Constance

Polar organic micropollutants (MPs) can have ecotoxicological effects on aquatic ecosystems and their occurrence in drinking water is a threat to public health. An extensive exposure assessment of MPs in large river and lake catchments is a necessary but challenging proposition for researchers and regulators. To get a complete picture of MP exposure in a large catchment, we employed a novel integrated strategy including MP measurement in the international catchment of Lake Constance and mass-flux modeling. A comprehensive screening of 252 MPs in the lake water by high-resolution mass spectrometry was used to identify the most commonly present MPs for the study site. It was found that the wastewater borne MPs diclofenac, carbamazepine, sulfamethoxazole, acesulfame, sucralose, benzotriazole, and methylbenzotriazole accounted for the most frequent and prominent findings. The concentration pattern of these compounds in the catchment was calculated based on regionalized inputs from wastewater treatment plants (WWTPs) and substance specific elimination rates. In 52, 8, and 3 of the 112 investigated river locations the concentration exceeded the predicted no-effect levels for diclofenac, sulfamethoxazole and carbamazepine, respectively. By coupling the catchment and lake model the effect of future trends in usage as well as possible mitigation options were evaluated for the tributaries and the lake. The upgrade of the major WWTPs in the catchment with a postozonation step would lead to a load reduction between 32% and 52% for all substances except for sucralose (10%).

Polycyclic aromatic hydrocarbons in wastewater, WWTPs effluents and in the recipient waters of Beijing, China

In this study, surface water samples from the Wenyu River and the North Canal, effluent from major wastewater treatment plants (WWTPs) in Beijing, and wastewater from open sewers that discharge directly into the river system were collected and analyzed for 16 priority USEPA polycyclic aromatic hydrocarbons (PAHs). Concentrations of these 16 PAHs ranged from 193 to 1790 ng/L in river surface waters, 245 to 404 ng/L in WWTP effluents, and 431 to 2860 ng/L in the wastewater from the small sewers. The WWTP effluent was the main contributor of dissolved PAHs to the river, while wastewater from the small sewers contributed both dissolved and suspended particulate matter-associated PAH to the river as indicated by the high dissolved organic carbon and suspended particulate matter contents in the wastewater. Although the flow from each open sewer was small, a PAH discharge as high as 44 kg/year could occur into the river from these types of sewers. This amount was equivalent to about 22 % of the PAH loads discharged into the North Canal downstream from Beijing, whereas the remainder was mainly released by the major WWTPs in Beijing.