Concentrations In Source Water Research Articles

Effects of wind-driven current and thermal dynamics in a temperate monomictic reservoir: Implications for manganese transport and treatment in water supply systems

Increasing manganese (Mn) concentrations in source water contribute to aesthetic and health-related concerns in drinking water. The challenges with Mn in drinking water primarily arise from elevated Mn concentrations in the water supply reservoir, with the inefficacy of Mn treatment largely attributed to fluctuating Mn levels in the water source. A three-dimensional Mn cycle model in a temperate monomictic reservoir, Tarago Reservoir, and a decision support system reflecting Mn variations in the local water treatment plant have been established in previous research. This study aimed to examine Mn variations from the reservoir to raw water and treated water under the influence of wind conditions during different stages of thermal structure, and discover valuable recommendations for Mn treatment in the local water supply system. We crafted 12 scenarios to scrutinize the impact of varying intensities of offshore and onshore winds on hydrodynamic processes and Mn transport during strong thermal stratification, weak thermal stratification, and turnover. The scenario analysis revealed that, during the gradual weakening of thermal stratification, offshore wind induced a substantial amount of Mn to the upper layers near the water intake point. Conversely, onshore wind hindered the upward transport of Mn. The simulated Mn in the raw water under the 12 scenarios indicated that the timing of turnover in the Tarago Reservoir is the primary concern for Mn treatment in the water treatment plant. Additionally, close attention should be given to the frequency and intensity of offshore winds during the weakening of thermal stratification.

Characterizing PFAS concentrations in drinking water treatment residuals

AbstractWhile drinking water treatment plants (DWTPs) are not considered a source of per‐ and polyfluoroalkyl substances (PFAS), PFAS concentrate in treatment residuals relative to their source water concentrations. Regulatory actions considered for PFAS‐impacted residuals could affect the cost and viability of conventional residual management practices. This study estimated the annual quantity of residuals generated in the United States and presents a framework for understanding how PFAS may concentrate in these residual streams. Findings of this work indicate that PFAS may substantially impact DWTP residuals management, especially coagulation and softening solids, at concentration factors greater than 100 and spent adsorbents at PFAS concentration factors greater than 10,000. If potential regulatory actions were to apply to coagulation and softening residuals, those regulations must consider impacts on disposal of more than 420,000,000 wet tons of at‐risk DWTP residuals which are generated annually.

The effect of green sorption media pretreatment on nanofiltration during water treatment for long- and short-chain per- and polyfluoroalkyl substances (PFAS) removal

Short-chain per- and polyfluoroalkyl substances (PFAS) have higher mobility than long-chain PFAS. This study investigated the application potential of two specialty adsorbents as pretreatment media for nanofiltration (NF) to enhance the removal of both short- and long-chain PFAS from water matrices. In this hybrid process, two specialty adsorbents, known as green sorption media (GSM), were prepared using recycled and natural materials for cost-effective, scalable, and sustainable water pretreatment. These two GSM are named the clay-perlite and sand (CPS) sorption media and zero-valent iron and perlite-based green environmental media (ZIPGEM). Such pretreatment led to significant removal of long-chain PFAS (up to 100 %) in addition to natural organic matter (NOM) and Ca2+ from the source water (canal water); however, for the short-chain PFAS (Perfluorobutanoic acid and Perfluorobutanesulfonic acid), the removal rate only rose to approximately 25 %. Such a contrasting removal rate is attributable to the source water concentration of PFAS and the hydrophobic and electrostatic interactions of the compounds within the treatment media. Yet the CPS–NF and ZIPGEM–NF hybrid processes exhibited significantly higher removal of perfluorooctanesulfonic acid (long-chain PFAS; approximately 16 % higher) when compared to the control (i.e., NF only). Because the pretreatment media removed higher percentages of long-chain PFAS, NOM, and Ca2+ from the water, the performance of the subsequent NF declined due to less calcium bridging involving NOM and PFAS and less micelle/complex formation by the compounds in bulk water. However, the integration of GSM with NF significantly improved (up to approximately 25 % higher) PFAS removal efficiency via the hybrid functionality. This signifies the membrane plays a complementary role in enhancing the overall removal efficiency of PFAS. In addition to contributing to PFAS removal from the source water, GSM pretreatment can help reduce NF membrane fouling/scaling by removing NOM and cations.

Calculating Required Purification Effort to Turn Source Water Into Drinking Water Using an Adapted CCME Water Quality Index

AbstractThe 2000 European Union Water Framework Directive (WFD) states that “Member States shall ensure the necessary protection for the bodies of water identified with the aim of avoiding deterioration in their quality in order to reduce the level of purification treatment required in the production of drinking water.” However, it does not specify how to evaluate or quantify this level of purification treatment. We propose a novel water quality index (WQI) to quantify the level of purification treatment required to prepare drinking water from source water. It is based on the WQI of the Canadian Council of Ministers of the Environment (CCME WQI). Our WQI compares measured contaminant concentrations in source water to drinking water guidelines and any exceedance is weighted by a measure of the resilience of that contaminant to the treatment processes, which is not possible in the CCME WQI. Furthermore, it accommodates for varying sampling frequencies that are characteristic of the ongoing monitoring program. These adaptations make our index robust and sensitive to relevant changes in source water quality. We calculated index scores for source water from the Rhine and the Meuse and found no general decrease in required purification treatment levels since the introduction of the WFD.

Organophosphate tri- and diesters in source water supply and drinking water treatment systems of a metropolitan city in China.

The water contaminations with organophosphate triesters (tri-OPEs) and diesters (di-OPEs) have recently provoked concern. However, the distributions of these compounds in natural water sources and artificial water treatment facilities are poorly characterized. A comprehensive study was therefore performed to measure their concentrations in a water source, a long-distance water pipeline, and a drinking water treatment plant (DWTP). Eight tri-OPEs and 3 di-OPEs were found to be widely distributed, with total concentrations in source water and pipelines ranging from 290.6 to 843.9ng/L. The most abundant pollutants were tris(1-chloro-2-propyl) phosphate (TCPP), triethyl phosphate, tri-n-butyl phosphate (TnBP), and diphenyl phosphate (DPhP). Di-OPEs appeared to be removed less efficiently in the DWTP than the parent tri-OPEs, and the elimination efficiencies of tri-OPEs were structure-dependent. Long-distance pipeline transportation had no significant effect on the distributions of tri- and di-OPEs. Statistical analysis suggested that the sources of di-OPEs and the corresponding tri-OPEs differed, as did those of DPhP and di-n-butyl phosphate. A risk analysis indicated that tri-OPEs present limited ecological risks that are mainly due to TnBP and TCPP, and that the human health risks of tri-OPEs are negligible. However, di-OPEs (especially DPhP) may increase these risks. Further studies on the risks posed by di-OPEs in aquatic environments are therefore needed.

Silicon, Its Forms and Methods of Determination in Water Bodies: A Review

Background: Characteristics of silicon and its compounds found in water bodies and recently updated standards for their content in drinking water regulated by Russian Sanitary Rules and Norms SanPiN 2.1.4.3685–21, Hygienic standards and re- quirements for ensuring safety and/or harmlessness of environmental factors for humans, necessitate optimal and affordable methods of determination of silicon for drinking water quality control purposes. Objective: To summarize published data on the forms of silicon and methods of their quantitative determination in source and drinking water. Materials and methods: Information and analytical methods based on summarization and analysis of data of scientific papers published in 1923–2020 and cited by Scopus and RSCI international scientometric databases were applied. The search terms included silicon, drinking water, silicon compounds, and methods of quantitative determination. The initial sample consist- ed of 57 articles, of which 14 were excluded after primary screening and 43 publications compliant with selection criteria were reviewed. Results: Published data summarization has demonstrated the prevalence monomeric and dimeric species of silicic acid and soluble silicate ions in most water bodies. Conclusion: The silicomolybdic acid spectrophotometry is the method of choice for determination of silicon concentrations in source water.

Changes in Escherichia coli to enteric protozoa ratios in rivers: Implications for risk-based assessment of drinking water treatment requirements

Minimum treatment requirements are set in response to established or anticipated levels of enteric pathogens in the source water of drinking water treatment plants (DWTPs). For surface water, contamination can be determined directly by monitoring reference pathogens or indirectly by measuring fecal indicators such as Escherichia coli (E. coli). In the latter case, a quantitative interpretation of E. coli for estimating reference pathogen concentrations could be used to define treatment requirements. This study presents the statistical analysis of paired E. coli and reference protozoa (Cryptosporidium, Giardia) data collected monthly for two years in source water from 27 DWTPs supplied by rivers in Canada. E. coli/Cryptosporidium and E. coli/Giardia ratios in source water were modeled as the ratio of two correlated lognormal variables. To evaluate the potential of E. coli for defining protozoa treatment requirements, risk-based critical mean protozoa concentrations in source water were determined with a reverse quantitative microbial risk assessment (QMRA) model. Model assumptions were selected to be consistent with the World Health Organization (WHO) Guidelines for drinking-water quality. The sensitivity of mean E. coli concentration trigger levels to identify these critical concentrations in source water was then evaluated. Results showed no proportionalities between the log of mean E. coli concentrations and the log of mean protozoa concentrations. E. coli/protozoa ratios at DWTPs supplied by small rivers in agricultural and forested areas were typically 1.0 to 2.0-log lower than at DWTPs supplied by large rivers in urban areas. The seasonal variations analysis revealed that these differences were related to low mean E. coli concentrations during winter in small rivers. To achieve the WHO target of 10−6 disability-adjusted life year (DALY) per person per year, a minimum reduction of 4.0-log of Cryptosporidium would be required for 20 DWTPs, and a minimum reduction of 4.0-log of Giardia would be needed for all DWTPs. A mean E. coli trigger level of 50 CFU 100 mL−1 would be a sensitive threshold to identify critical mean concentrations for Cryptosporidium but not for Giardia. Treatment requirements higher than 3.0-log would be needed at DWTPs with mean E. coli concentrations as low as 30 CFU 100 mL−1 for Cryptosporidium and 3 CFU 100 mL−1 for Giardia. Therefore, an E. coli trigger level would have limited value for defining health-based treatment requirements for protozoa at DWTPs supplied by small rivers in rural areas.

Acute health effects associated with satellite-determined cyanobacterial blooms in a drinking water source in Massachusetts

BackgroundThe occurrence of cyanobacterial blooms in freshwater presents a threat to human health. However, epidemiological studies on the association between cyanobacterial blooms in drinking water sources and human health outcomes are scarce. The objective of this study was to evaluate if cyanobacterial blooms were associated with increased emergency room visits for gastrointestinal (GI), respiratory and dermal illnesses.MethodsSatellite-derived cyanobacteria cell concentrations were estimated in the source of drinking water for the Greater Boston area, during 2008–2011. Daily counts of hospital emergency room visits for GI, respiratory and dermal illnesses among drinking water recipients were obtained from an administrative record database. A two-stage model was used to analyze time-series data for an association between cyanobacterial blooms and the occurrence of illnesses. At the first stage, predictive autoregressive generalized additive models for Poisson-distributed outcomes were fitted to daily illness count data and daily predictive variables. At the second stage, residuals from the first stage models were regressed against lagged categorized cyanobacteria concentration estimates.ResultsThe highest cyanobacteria concentration (above the 75th percentile) was associated with an additional 4.3 cases of respiratory illness (95% confidence interval: 0.7, 8.0, p = 0.02, n = 268) compared to cyanobacteria concentrations below the 50th percentile in a two-day lag. There were no significant associations between satellite derived cyanobacterial concentrations and lagged data on GI or dermal illnesses.ConclusionThe study demonstrated a significant positive association between satellite-derived cyanobacteria concentrations in source water and respiratory illness occurring 2 days later. Future studies will require direct measures of cyanotoxins and health effects associated with exposure to cyanobacteria-impacted drinking water sources.

Using surrogate data to assess risks associated with microbial peak events in source water at drinking water treatment plants

A monitoring strategy was implemented at two drinking water treatment plants in Quebec, Canada, to evaluate microbial reduction performances of full-scale treatment processes under different source water conditions. β-D-glucuronidase activity in source water was automatically monitored in near-real-time to establish baseline and event conditions at each location. High-volume water samples (50–1,500 L) were collected at the inflow and the outflow of coagulation/flocculation, filtration, and UV disinfection processes and were analysed for two naturally occurring surrogate organisms: Escherichia coli and Clostridium perfringens. Source water Cryptosporidium data and full-scale C. perfringens reduction data were entered into a quantitative microbial risk assessment (QMRA) model to estimate daily infection risks associated with exposures to Cryptosporidium via consumption of treated drinking water. Daily mean E. coli and Cryptosporidium concentrations in source water under event conditions were in the top 5% (agricultural site) or in the top 15% (urban site) of what occurs through the year at these drinking water treatment plants. Reduction performances of up to 6.0-log for E. coli and 5.6-log for C. perfringens were measured by concentrating high-volume water samples throughout the treatment train. For both drinking water treatment plants, removal performances by coagulation/flocculation/sedimentation processes were at the high end of the range of those reported in the literature for bacteria and bacterial spores. Reductions of E. coli and C. perfringens by floc blanket clarification, ballasted clarification and rapid sand filtration did not deteriorate during two snowmelt/rainfall events. QMRA results suggested that daily infection risks were similar during two rainfall/snowmelt events than during baseline conditions. Additional studies investigating full-scale reductions would be desirable to improve the evaluation of differences in treatment performances under various source water conditions.

Atrazine and its metabolites (ATZs) in source water, finished water, and tap water from drinking water treatment plants and its human risk assessment in Zhoukou City, China

A study to monitor atrazine (ATZ) and its metabolites (ATZs) (including DEA, deethylatrazine; DIA, deisopropylatrazine; HA, hydroxyatrazine) in drinking water treatment plants from water source to consumers tap in Zhoukou City was undertaken. A total of 20 source water, 36 finished water, and 36 tap water samples were collected during the period from July to August in 2020. Based on the survey results, a human health non-carcinogenic and carcinogenic risk assessment was conducted for adults and children. The results showed that the ΣATZs concentrations in source water, finished water, and tap water ranged from 0.609 to 55.985 ng/L (mean = 6.065 ng/L), 0.445 to 46.3 ng/L (mean = 4.507 ng/L), and 0.475 to 91.9 ng/L (mean = 7.139 ng/L), respectively. The predominant compounds of ATZs in tap water was ATZ, with a detection frequency of 91.67%, followed by DIA (58.33%), DEA (52.78%), and HA (27.78%). The highest concentrations of ΣATZs (mean = 15.110 ng/L) in tap water was found in the Central of Zhoukou City, followed by Southern (mean = 2.817 ng/L), Western (mean = 2.338 ng/L), Eastern (mean = 1.027 ng/L), and Northern (mean = 0.51 ng/L). The HQ of ΣATZs in tap water of Zhoukou City was lower than 1 and the highest value was 4.59E − 04, which suggesting that ATZs are considered unlikely to pose non-carcinogenic effects to individuals. Carcinogenic risk caused by ΣATZs for adults was much lower than 1.0E − 06, while the highest risk caused by ΣATZs for children through tap water was 6.34E − 06.

Electroanalytical determination of acetaminophen using polymerized carbon nanocomposite based sensor

Acetaminophen (AC) is one of the most commonly consumed painkillers worldwide and hence its increased use leads to higher concentrations in source water, thus needful its analysis. The voltammetric analysis of AC using the fabricated sensor was presented in this article. The voltammetric sensor based on the poly asparagine modified carbon nanotube and graphene mixed paste electrode (PASMCNTMGPE) was constructed. The constructed electrode unveiled a boosted electrocatalytic activity towards the detection of AC than the unmodified electrode through the cyclic voltammetry (CV) and differential pulse voltammetry (DPV) technique. The Field Emission Scanning Electron Microscopy (FE-SEM) was utilized to verify the morphological feature of the designed electrode. The charge transfer resistance of the designed electrode was studied by electrochemical impedance spectroscopy (EIS). Some of the factors influencing the voltammetric signal of AC such as the number of electropolymerisation cycles and pH were optimized. The redox reaction of AC at the PASMCNTMGPE is a pH-dependent and adsorption-controlled process. The designed electrode yielded a low detection limit (4.10 × 10 −8 M) for AC. In addition, the prepared electrode demonstrated an excellent anti-fouling property, reliability, selectivity, and repeatability. More importantly, the feasibility of the constructed sensor was evaluated by analyzing AC in the pharmaceutical and biological samples.

Perfluoroalkyl substances in drinking water sources along the Yangtze River in Jiangsu Province, China: Human health and ecological risk assessment

Perfluoroalkyl substances (PFASs) in source water is of growing concern for its adverse effects on human health and wildlife as well. The Yangtze River is the vital drinking water source in Jiangsu Province of China, but little attention has been paid on PFASs. The occurrence, spatial distribution and temporal trend of PFASs in 21 water sources along the Jiangsu section of the Yangtze River was investigated with sampling from 2018 to 2020. Moreover, health risk of PFASs was assessed by estimated intake dose and derived tolerable intake dose, while ecological risk was assessed by selected effect concentration and environmental exposure. PFASs concentrations in source water ranged from 12.0 to 128 ng/L, with perfluorooctanoic acid (PFOA) as the dominated congener. Fluorine chemical industry lead to a great increase of perfluorohexanoic acid (PFHxA) in its nearest water source. The estimated daily intake of PFASs through drinking was 0.54 and 0.82 ng/kg bw/day for adults and children. The major health risk was from perfluorooctane sulfonate (PFOS) and PFOA for their toxicity on liver, reproduction, development and immunity, with the maximum hazard quotient of 0.029 and 0.043 for adults and children in the worst scenario. The ecological risks from PFASs on nine species groups ranged from 2.7 × 10−10 to 5.2. PFOA and Perfluorobutane sulfonate (PFBS) were causing significant risk on wildlife, particularly on worms, mussels, and fish, which may further influence the structure and processes in the foodweb. Overall, PFASs, especially PFOS, PFOA and PFBS, induced considerable risk on human health and aquatic species in some hotspot area. It would be necessary to include them into monitoring in China and develop standards for different protection purposes.

A global reconnaissance of particulates and metals/metalloids in untreated drinking water sources

Metal and metalloid contamination in drinking water sources is a global concern, particularly in developing countries. This study used hollow membrane water filters and metal-capturing polyurethane foams to sample 71 drinking water sources in 22 different countries. Field sampling was performed with sampling kits prepared in the lab at Hope College in Holland, MI, USA. Filters and foams were sent back to the lab after sampling, and subsequent analysis of flushates and rinsates allowed the estimation of suspended solids and metal and other analayte concentrations in source waters. Estimated particulate concentrations were 0–92 mg/L, and consisted of quartz, feldspar, and clay, with some samples containing metal oxides or sulfide phases. As and Cu were the only analytes which occurred above the World Health Organization (WHO) guidelines of 10 μg/L and 2000 μg/L, respectively, with As exceeding the guideline in 45% of the sources and Cu in 3%. Except for one value of ~ 285 μg/L, As concentrations were 45–200 μg/L (river), 65–179 μg/L (well), and 112–178 μg/L (tap). Other metals (Ce, Fe, Mg, Mn, Zn) with no WHO guideline were also detected, with Mn the most common. This study demonstrated that filters and foams can be used for reconnaissance characterization of untreated drinking water. However, estimated metal and other analyte concentrations could only be reported as minimum values due to potential incomplete retrieval of foam-bound analytes. A qualitative reporting methodology was used to report analytes as “present” if the concentration was below the WHO guideline, and “present-recommend retesting” if the concentration was quantifiable and above the WHO guideline.

Occurrence and spatio-seasonal distribution of organophosphate tri- and di-esters in surface water from Dongting Lake and their potential biological risk

In this study, 24 surface water samples were collected from Dongting Lake, China, in the wet and dry seasons, then the concentrations, composition profiles and spatio-seasonal variations of nine organophosphate triesters (OPEs) and five organophosphate diesters (Di-OPs) were determined. Significantly higher total OPE concentrations (∑OPEs) were observed in the wet season (49.5–148 ng L−1) than in the dry season (5.00–45.7 ng L−1) suggesting higher input via tributaries discharge as well as wet deposition in the studied region. Whereas lower levels of TnBP and (triphenyl phosphate (TPHP) in wet season reflected their possible degradation under solar irradiation. Comparable levels of total Di-OPs (∑Di-OPs) were found in the wet season (3.41–13.9 ng L−1) and dry season (1.01–12.3 ng L−1). Tri(2-chloroethyl) phosphate and tris(2-chloroisopropyl) phosphate were the main OPE components, while diphenyl phosphate, di-n-butyl phosphate and bis(1,3-dichloro-2-propyl) phosphate were the main Di-OP components. High levels of OPEs and Di-OPs were found in Datong Lake suggesting possible local emissions potentially related to fishery activity in the land-locked lake. Samples at river mouths to the lake also have higher levels of target OPEs and Di-OPs, the results disclosed obvious discharges from tributaries in Hunan Province. Negligible non-carcinogenic and carcinogenic risks were determined based on the measured concentrations in source waters. A limited ecological risk aquatic organisms in the Dongting Lake was identified, with most risk from TPHP.

Demonstrating the reduction of enteric viruses by drinking water treatment during snowmelt episodes in urban areas

This study investigates short-term fluctuations in virus concentrations in source water and their removal by full-scale drinking water treatment processes under different source water conditions. Transient peaks in raw water faecal contamination were identified using in situ online β-d-glucuronidase activity monitoring at two urban drinking water treatment plants. During these peaks, sequential grab samples were collected at the source and throughout the treatment train to evaluate concentrations of rotavirus, adenovirus, norovirus, enterovirus, JC virus, reovirus, astrovirus and sapovirus by reverse transcription and real-time quantitative PCR. Virus infectivity was assessed through viral culture by measurement of cytopathic effect and integrated cell culture qPCR. Virus concentrations increased by approximately 0.5-log during two snowmelt/rainfall episodes and approximately 1.0-log following a planned wastewater discharge upstream of the drinking water intake and during a β-d-glucuronidase activity peak in dry weather conditions. Increases in the removal of adenovirus and rotavirus by coagulation/flocculation processes were observed during peak virus concentrations in source water, suggesting that these processes do not operate under steady-state conditions but dynamic conditions in response to source water conditions. Rotavirus and enterovirus detected in raw and treated water samples were predominantly negative in viral culture. At one site, infectious adenoviruses were detected in raw water and water treated by a combination of ballasted clarification, ozonation, GAC filtration, and UV disinfection operated at a dose of 40 mJ cm−2. The proposed sampling strategy can inform the understanding of the dynamics associated with virus concentrations at drinking water treatment plants susceptible to de facto wastewater reuse.

Decomposition of β-N-methylamino-L-alanine (BMAA) and 2,4-diaminobutyric acid (DAB) during chlorination and consequent disinfection byproducts formation

β-N-methylamino-L-alanine (BMAA) and 2,4-diaminobutyric acid (DAB) are two newly identified algal toxins, and they may react with chlorine to undergo decomposition and generate disinfection byproducts (DBPs) during pre-chlorination as well as chlorine disinfection. In this study, the decomposition of BMAA and DAB during chlorination and the consequent DBPs formation were investigated. The BMAA and DAB concentrations in source waters were determined, the decomposition kinetics of BMAA and DAB and the formation of DBPs during chlorination were studied, the formation pathways of DBPs from BMAA and DAB were explored, and the factors which may affect the decomposition and DBPs formation were examined. The results revealed that BMAA and DAB were commonly detected in source waters from Taihu Lake, and the highest level of BMAA reached 230.8 ng/L, while the concentrations of DAB were generally around 2.0 ng/L. The decomposition of BMAA and DAB during chlorination both followed pseudo-first-order decay while the decomposition rate constant of DAB was significantly higher than that of BMAA. Trihalomethanes (THMs), haloacetic acids (HAAs), and haloacetonitriles (HANs) were all generated during the chlorination of BMAA and DAB with relatively high yields. Notably, the THMs, HAAs, and HANs yields of each carbon atom from BMAA and DAB were significantly higher than that from other organic precursors, and the formation of HANs from DAB was significantly higher than that from BMAA. The formation pathways of DBPs from BMAA and DAB were tentatively proposed and verified through theoretical calculations. Of note, the proposed formation pathways of THMs and HAAs from BMAA were similar to that from DAB, while the proposed formation pathways of HANs from BMAA and DAB showed some differences. Chlorine dose, pH and temperature all affected the decomposition of BMAA and DAB and DBPs formation during chlorination.

QMRA of adenovirus in drinking water at a drinking water treatment plant using UV and chlorine dioxide disinfection

According to the Dutch Drinking Water Act of 2011, Dutch drinking water suppliers must conduct a Quantitative Microbial Risk Assessment (QMRA) for infection by the following index pathogens: enterovirus, Campylobacter, Cryptosporidium and Giardia at least once every four years in order to assess the microbial safety of drinking water. The health-based target for safe drinking water is set at less than one infection per 10 000 persons per year. At Evides Water Company, concern has arisen whether their drinking water treatment, mainly based on UV inactivation and chlorine dioxide, reduces levels of adenovirus (AdV) sufficiently. The main objective was, therefore, to conduct a QMRA for AdV. Estimates of the AdV concentrations in source water were based on enumeration of total AdV by integrated cell culture PCR (iccPCR), most probable number PCR (mpnPCR) and quantitative PCR (qPCR), and on enumeration of AdV40/41 by mpnPCR and qPCR. AdV40/41 represents a large fraction of total AdV and only a small fraction of AdV is infectious (1/1700). By comparison of literature data and plant scale data, somatic coliphages appeared a good, conservative indicator for AdV disinfection by UV irradiation. Similarly, bacteriophage MS2 appeared to be a good, conservative indicator for disinfection by chlorine dioxide. Literature data on the efficiency of chlorine dioxide disinfection were fitted with the extended HOM model. Chlorine dioxide disinfection at low initial concentrations (0.05–0.1 mg/l) was found to be the major treatment step, providing sufficient treatment on its own for compliance with the health-based target. UV disinfection of AdV at 40 mJ/cm2 or 73 mJ/cm2 was insufficient without chlorine dioxide disinfection.

Impact of Soil Filtration on Metals, Nutrients, and Estrogenic Activity of Reclaimed Water

This study examined the impact of soil filtration on water quality for reclaimed water from two municipal wastewater treatment processes with two soils (forest and farm). Soils were watered for 16 wk. Nutrients (NO-N, NH-N, and PO), electrical conductivity, hardness, pH, total metals, and estrogenic activity in source and effluents were measured. Results were evaluated in reference to current regulations in Washington State. Both reclaimed waters met standards for unrestricted agricultural use but did not meet current state regulations for ecological use. Metal concentrations in reclaimed waters were generally similar to the control (tap water). Both source and soil filtered water met Washington State stream water criteria for chronic exposure for As but exceeded groundwater standards. Concentrations of Cd, Pb, Ag, and Zn in the effluents were similar or slightly elevated to reclaimed source water for both soils and water types. Soil filtration improved water quality to levels within Washington State regulatory limits for ecological use for Cd, Cu, and Zn but decreased water quality for Pb for both soil and reclaimed water types. Phosphate concentrations were reduced by soil filtration, but NO concentrations were increased for both soils and all water types above source water concentrations. The estrogenic activity of the sand-filtered water decreased to near detection limits in the forest soil and by >200% in the farm soil. The degradation in water quality (increased NO, As, and Mn) after soil filtration observed in this study would likely occur with any water type, including rainwater.

Target virus log10 reduction values determined for two reclaimed wastewater irrigation scenarios in Japan based on tolerable annual disease burden

Multiple-barriers are widely employed for managing microbial risks in water reuse, in which different types of wastewater treatment units (biological treatment, disinfection, etc.) and health protection measures (use of personal protective gear, vegetable washing, etc.) are combined to achieve a performance target value of log10 reduction (LR) of viruses. The LR virus target value needs to be calculated based on the data obtained from monitoring the viruses of concern and the water reuse scheme in the context of the countries/regions where water reuse is implemented. In this study, we calculated the virus LR target values under two exposure scenarios for reclaimed wastewater irrigation in Japan, using the concentrations of indigenous viruses in untreated wastewater and a defined tolerable annual disease burden (10−4 or 10−6 disability-adjusted life years per person per year (DALYpppy)). Three genogroups of norovirus (norovirus genogroup I (NoV GI), geogroup II (NoV GII), and genogroup IV (NoV GIV)) in untreated wastewater were quantified as model viruses using reverse transcription-microfluidic quantitative PCR, and only NoV GII was present in quantifiable concentration. The probabilistic distribution of NoV GII concentration in untreated wastewater was then estimated from its concentration dataset, and used to calculate the LR target values of NoV GII for wastewater treatment. When an accidental ingestion of reclaimed wastewater by Japanese farmers was assumed, the NoV GII LR target values corresponding to the tolerable annual disease burden of 10−6 DALYpppy were 3.2, 4.4, and 5.7 at 95, 99, and 99.9%tile, respectively. These percentile values, defined as “reliability,” represent the cumulative probability of NoV GII concentration distribution in untreated wastewater below the corresponding tolerable annual disease burden after wastewater reclamation. An approximate 1-log10 difference of LR target values was observed between 10−4 and 10−6 DALYpppy. The LR target values were influenced mostly by the change in the logarithmic standard deviation (SD) values of NoV GII concentration in untreated wastewater and the reliability values, which highlights the importance of accurately determining the probabilistic distribution of reference virus concentrations in source water for water reuse.

Electrochemical sensing of acetaminophen using multi-walled carbon nanotube and β-cyclodextrin

Acetaminophen is one of the most commonly and widely used painkillers worldwide. Because of its increased use in the past several decades, APAP is now present at higher concentrations in source water, thus necessitating its monitoring. In this work, we report a low-temperature, solution-processed modification of multi-walled carbon nanotubes (MWCNT) with β-cyclodextrin (βCD) on glassy carbon electrode for detecting low levels of acetaminophen in water. This process combines the adsorption properties of βCD with high surface area of carbon nanotubes. An improved dispersion of MWCNT was observed due to the hydrophilicity of βCD. A surface-limited process involving equal number of protons and electrons controlled the electrochemical reaction of acetaminophen with the sensor. The sensor’s limit of detection was 11.5nM and its linear response was from 50nM to 300μM. The sensors exhibited a reproducible and stable response over four weeks and negligible interference from commonly present chemicals in urine, such as dopamine and ascorbic acid. These promising results could facilitate the development of simple and low-cost electrochemical sensors for monitoring of APAP in water.