A source-based framework to estimate the annual load of PFAS in municipal wastewater

Per- and Polyfluoroalkyl substances (PFAS) are a class of persistent chemicals, whose impact has been observed in various environmental compartments. Wastewater treatment plants (WWTPs) are considered a major emission pathway of PFAS, specifically in the context of the aquatic environment. The goal of this study was to develop a compartmentalized, source-based load estimation model of 7 PFAS within the municipal wastewater influent. Consumer statistics, data from literature on PFAS concentrations and release during use, and specific sampling activities for environmental flows in the related city were used to estimate per capita emission loads. Model results were compared with loads obtained through the monitoring campaign at the municipal WWTP influent. A wide range of discrepancies (≈5 % to ≈90 %) between loads observed in the WWTP influent and source based model estimates was noticed. The loads less accounted by the model were associated with sulfonic acids (PFSAs), whereas for carboxylic acids (PFCAs) most of the observed loads could be reasonably explained by the model, with even an overestimation of nearly 5 % noted for PFNA. Higher heterogeneity in sources was observed in the PFCA group, with a noticeable dominance in the share of consumer products. PFSAs had less of a consumer product input (<20 %), with the rest of the modelled load being attributed to environmental inputs. A large gap of unknown loads of PFSAs indicates a need for examination of other, not yet quantified activities that can potentially explain the remainder of the observed load. Especially commercial activities are considered as potential additional sources for PFSAs. These findings signify the importance of PFAS that originate from both consumer products, as well as environmental inputs in the overall load contribution into the sewage, while identifying the need for further investigation into commercial sources of PFAS emitted into the municipal wastewater.

Predicting wastewater treatment plant influent in mixed, separate, and combined sewers using nearby surface water discharge for better wastewater-based epidemiology sampling design

For wastewater sample collection approaches supporting public health applications, few high hydrologic activity normalizing guidelines currently consider readily available environmental flow data that may earlier capture information regarding periods of influent mixing and dilution of wastewater with groundwater and runoff. This study aimed to identify wastewater sampling rules for high hydrological activity events, allowing for an earlier decision point in the control of dilution before sample collection. We defined the sampling rules via data-driven models (Random Forest and linear regression) using environmental data (i.e., wastewater treatment facility influent rates, nearby stream discharge flow, and precipitation). These models were applied to five treatment plants in Jefferson County, Kentucky (USA) in mixed, separate, and combined sewers with different population sizes. We proposed cutoffs of 10 %, 25 %, and 50 % flow conditions for orientation towards public health samples. The results showed a strong nonlinear relationship between nearby stream discharge and treatment facility flow rates, which was used to infer the hydrological conditions that produce high volumes of diluted wastewater in the sewer system. Accumulated Local Effects and SHapley Additive exPlanations aided in deciphering the relationship between the predictors and response variables of the Random Forest models. The influent rate to the treatment plant from the previous day and two USGS stream gages were needed to adequately predict the degree of infiltration and inflow mixing on a given day. Surface water discharge data can be used to provide an earlier workflow decision point during wet weather periods to improve understanding of flow conditions for wastewater-based epidemiological studies to inform laboratory analysis and data interpretation. Not only total flow, but also the specific proportions of infiltration and inflow to wastewater volume in influent should be considered when analyzing data for normalization purposes, and our method provides a starting point for doing so rapidly and at low cost.

Direct injection liquid chromatography-tandem mass spectrometry as a sensitive and high-throughput method for the quantitative surveillance of antimicrobials in wastewater

Environmental antimicrobial pollution and antimicrobial resistance pose a threat to environmental and human health. Wastewater analysis has been identified as a promising tool for antimicrobial monitoring and the back-estimation of antimicrobial consumption, but current pretreatment methods are tedious and complicated, limiting their scope for high-throughput analysis. A sensitive direct injection method for the quantification of 109 antimicrobials and their metabolites in wastewater samples was developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The method was validated for both wastewater influent and effluent in terms of specificity, calibration range, matrix effect, filtration loss, accuracy, precision, limit of detection (LOD), and limit of quantification (LOQ). Most analytes achieved calibration of R2 > 0.99, and the calibration range was from 0.0002 to 150 μg L-1. Recoveries ranged consistently between ~50 % and ~100 % and losses were attributed to sample filtration. Method LOQs were determined as low as 0.0003 μg L-1, and acceptable accuracy (75 %-125 %) and precision (within 25 %) were achieved for >90 % of the analytes. The method was subsequently further assessed using wastewater of raw influent and treated effluent collected from 6 Australian wastewater treatment plants in 2021. In total, 37 analytes were detected in influent and 22 in effluent. Most of them could be quantified at concentrations ranging from 0.0053 to 160 μg L-1, with benzalkonium chloride-C12, amoxicilloic acid, and cephalexin detected at the highest concentrations. The current study provides a straightforward analytical method for antimicrobial monitoring in wastewater with a fast and simple pretreatment procedure.

Tracking contaminants of concern in wet-weather sanitary sewer overflows

Four representative sites in the greater city of Sydney, Australia, were selected for a study of the wet-weather overflow of sanitary (separate to stormwater) sewerage systems. Water samples were collected by autosamplers from up to eight wet weather overflow events over 16 months and from companion receiving water sites. The objective was to identify the risks posed by sewage contaminants to aquatic biota in the receiving waters, to aid in prioritising management actions. Twelve organic contaminants were identified in influents across the four sites under rainfall ingress diluted conditions, with measurements showing that the highest concentrations were restricted to the anti-inflammatory acetaminophen and the diabetes medication metformin. Lesser contaminants included theobromine, ibuprofen, sucralose, and three benzotriazoles (mainly 1-H benzotriazole). An assessment of the toxicity of the identified organic chemicals indicated that none appeared to pose concerns for ecosystem health before wet-weather ingress dilution, and this was even less likely after dilution in the receiving waters. Metal concentrations were low; however, ammonia concentrations in the influent did pose a risk to ecosystem health, although receiving water dilution diminished this risk at four of the five receiving water locations studied.

Monitoring sewer systems to detect the eDNA of missing persons and persons of interest

The paper proposes a theoretical framework for using eDNA detection devices to locate missing persons, wanted criminals, and persons of interest in densely populated areas by monitoring sewer water. The proposed system includes a computer application to enter information on missing targets, and the data collected by the system can be used to narrow down their location for rescue or apprehension. The paper investigates eDNA persistence, sewer water studies, and current eDNA and DNA analysis tools to formulate a research concept. The limitations of the concept are mentioned, and it is suggested that collaboration between a large university and a leading DNA analysis equipment manufacturer is needed to custom-build eDNA detection devices to fulfill the requirements of the concept. Eventually, manufacturing costs will drive down the initial and nationwide adoption costs of the system.

Influence of seasonality, wastewater treatment plant process, geographical location and environmental parameters on bacterial community selection in activated sludge wastewater treatment plants treating municipal sewage in South Africa

This is the first comprehensive study that focusses on the correlation between the bacterial community composition and a range of previously identified selective criteria in activated sludge wastewater treatment plants on the African continent. Multivariate statistical analyses were used to determine the relative significance of the geographical location (factor: site), wastewater treatment plant process (factor: configuration), seasonality (factor: season), and environmental parameters on the bacterial communities in nine wastewater treatments plants from two sites in South Africa using terminal restriction fragment length polymorphism as a screening tool to rationalize the number of samples (to 50 samples) for high throughput (Illumina MiSeq) sequencing. Site was the most significant factor (Global ANOSIM R value = 0.91, p = 0.001), and it was established that the inter-site differences were not climatic in origin but related to differences in the composition of the influent and activated sludge. Previous studies that have reported associations between microbial community structure and environmental parameters have measured influent chemistry, and this is the first time, to our knowledge, that the comprehensive chemical character of activated sludge itself has been included in this type of study. It was found using BEST analysis that the activated sludge ammonia, activated sludge total phosphate and influent chemical oxygen demand were the most significant (p < 0.001) drivers for inter-site bacterial community selection (ANOSIM Global R values of 0.862, 0.782 and 0.428, respectively). This link would not have been established with only influent chemical analyses as there was no significant difference (t-test, p > 0.05) in the average influent phosphate concentrations between the 2 sites, but there was a highly significant difference (p < 0.001, t (15.5)>t-crit (2.01)) in the activated sludge total phosphate concentrations (20.8 ± 17.0 and 127.8 ± 40.2 mg/L). This is notable for all future studies on a global level aimed at identifying factors for selection of microbial communities in activated sludge.

Evaluation of SARS-CoV-2 RNA Presence in Treated and Untreated Hospital Sewage

Wastewater-based epidemiology (WBE) is a potential approach for determining the viral prevalence in a community. In the wake of the COVID-19 pandemic, researchers have begun to pay close attention to the presence of SARS-COV-2 RNA in various wastewaters. The potential for detecting SARS-CoV-2 RNA in hospital sewage could make it an invaluable resource for epidemiological studies. In this regard, two specialized hospitals dedicated to COVID-19 patients were chosen for this investigation. Both hospitals utilize the same wastewater treatment systems. The influent and effluents of the two hospitals were sampled in May and June of 2021, and the samples were evaluated for their chemical properties. According to the findings of this study, the wastewater qualities of the two studied hospitals were within the standard ranges. The sewage samples were concentrated using ultrafiltration and PEG precipitation techniques. The E and S genes were studied with RT-qPCR commercial kits. We found E gene of SARS-CoV-2 in 83.3% (5/6) and 66.6% (4/6) of wastewater samples from hospital 1 and hospital 2, respectively, using ultrafiltration concentration method. Wastewater samples taken after chlorine treatment accounted for 16.6% of all positive results. In addition, due to the small sample size, there was no significant correlation (p > 0.05) between the presence of SARS-CoV-2 in wastewater and the number of COVID-19 cases. Hospitals may be a source of SARS-CoV-2 pollution, thus it is important to monitor and enhance wastewater treatment systems to prevent the spread of the virus and safeguard the surrounding environment.

Persistence of wastewater-associated antibiotic resistant bacteria in river microcosms

The spread of antibiotic-resistant bacteria (ARB) associated with wastewater is a significant environmental concern, but little is known about the persistence and proliferation of these organisms in receiving water bodies after discharge. To address this knowledge gap, we performed a series of microcosm experiments in which river water was amended with either untreated or treated wastewater, and the abundance of viable ciprofloxacin-, Bactrim-, and erythromycin-resistant bacteria was monitored for 72 h. Both types of wastewater amendments significantly increased the initial abundance of ARB compared to microcosms containing only river water (all p < 0.03). The increase was greatest with untreated wastewater, but that effect decreased steadily over time. In contrast, microcosms amended with treated wastewater saw a smaller initial increase and more complex temporal dynamics. Following a brief lag, ARB abundance bloomed for all three of the antibiotics that we considered. This suggests that ARB that survive wastewater treatment are particularly hardy and may proliferate in riverine conditions after a short recovery period. To determine how interactions with the native river microbial community impacted the persistence of wastewater-associated ARB, an additional set of microcosms was prepared using filter-sterilized river water. Peak abundance in these microcosms was significantly higher by 1-2 orders of magnitude compared to microcosms containing an intact river microbial community (all p < 0.05), which suggests that biotic interactions play a significant role in regulating the persistence and proliferation of ARB. The data presented in this paper are among the first available that specifically consider persistence of viable ARB and represent an important step toward understanding AR-related human health risks downstream from wastewater discharge points and following sewer overflow events. Additional studies that consider longer time scales and the interplay of biotic and abiotic variables are essential for modeling public health risks associated with wastewater inputs of ARB to rivers and other aquatic environments.

Background release and potential point sources of per- and polyfluoroalkyl substances to municipal wastewater treatment plants across Australia

Wastewater treatment plants (WWTPs) are known to be significant sources of per- and polyfluoroalkyl substances (PFAS) to the environment. In this study, PFAS were measured in the influent of 76 municipal wastewater treatment plants (WWTPs) serving approximately 53% of the Australian population. Of fourteen target PFAS, twelve analytes including six C5-C10 perfluoroalkyl carboxylic acids (PFCAs), four C4-10 perfluoroalkyl sulfonic acids (PFSAs) and two fluorotelomer sulfonates (6:2 and 8:2 FTS) were detected. Of these, PFOS, PFHxS and PFHxA had the highest median concentrations. The per capita background release of Σ₁₂ PFAS to WWTP influent in Australia was estimated to be 8.1-24 μg/d/per person. The background release was supplemented by contributions from catchment specific point sources (i.e., industry, airports, military bases, and landfills), whereby the number of industrial sites positively correlated with the per capita mass load of Σ₁₂ PFAS (r = 0.5-0.63, p < 0.01). The per capita mass loads were extrapolated to the entire Australian population, with estimates suggesting that approximately 1 kg/d of Σ₁₂ PFAS reach WWTPs in Australia (300-400 kg annually), with more than half of the PFAS (∼59%) attributed to background release and the remaining (∼41%) to catchment specific point sources. These data provide insight into the release of major PFAS to wastewater at a national scale in Australia.

Occurrence of antibiotics in wastewater from hospital and convectional wastewater treatment plants and their impact on the effluent receiving rivers: current knowledge between 2010 and 2019

The increased usage of antibiotics over the recent years has been of great concern all over the world. It is estimated that about 100,000 tons to 200,000 tons of antibiotics are being consumed worldwide. This increased consumption of antibiotics is worrisome as this has resulted in their detection in wastewater treatment plants' (WWTPs) effluent due to the inability of WWTP to remove them during treatment processes. The antibiotics may emanate from hospital effluents, surface waters, and sediments around the world. However, the migration of antibiotics to the environment is detrimental to public health since it can lead to antibiotics resistance in both humans and animals which has now been reported to be one of the biggest threats to public health in this twenty-first century. This present review work established from literature the presence, concentrations, and types of antibiotics both in influents and effluents of various waste treatment plants, natural water bodies, and hospital wastewaters from different countries over the past 10 years (2010-2019). A total of 78 published articles containing information on the presence of antibiotics in convectional and hospital wastewater and also in surface water were retrieved from scientific databases such as ScienceDirect, Google Scholar, PubMed, and Web of Science. A total of 39 different types of antibiotics from 10 different classes of antibiotics and others were recorded. Among the articles reviewed, the most frequently detected antibiotics are the classes of sulfonamides (sulfamethoxazole) which were present in almost all the WWTPs at concentrations as high as 10-800 ng/l in influent and 3600-68,700 ng/l in effluent samples. Macrolides (clarithromycin, erythromycin, azithromycin), trimethoprim, quinolones (ofloxacin, ciprofloxacin, norfloxacin), and tetracyclines (tetracycline) were also highly present in all treatment plants. β-Lactam antibiotics were seldom detected which might be due to hydrolysis. Most of the antibiotics present were recorded in Asian countries such as China and Singapore which have occurrence frequency of 6-30% and in European countries such as Greece and Spain with frequencies of about 6-10%. Future researches on the need for development of more reliable and cost-effective technologies for antibiotic removal such as advanced oxidation processes and remediation methods are suggested for more research attention.

Reduction of antibiotic resistome in influent of a wastewater treatment plant (WWTP) via a chemically enhanced primary treatment (CEPT) process

Chemically enhanced primary treatment (CEPT) has been considered for maximizing wastewater energy recovery by enhancing the carbon captured through the primary treatment. However, evaluating the potential of CEPT as a primary treatment process for removing antibiotic resistance genes (ARGs) in the influent from a wastewater treatment plant (WWTP) has seldom been investigated. In this study, CEPT was conducted to assess simultaneous reduction of 13 major targeted ARGs and common pollutants in wastewater compared with primary sedimentation alone (non-CEPT). CEPT processes using three types of coagulants (PACl, FeCl₃ and alum) effectively reduced absolute abundance of ARGs and intI1 in the influent from municipal WWTP. Average log-removal of absolute abundance of ARGs was achieved up to 1.77 ± 0.41 along with 90% turbidity reduction compared to non-CEPT. Through the simultaneous reduction of ARGs and intI1 genes during a CEPT process, ARGs proliferation may be limited directly through reduction of antibiotic resistant bacteria or indirectly through decreasing the possibility of horizontal gene transfer by intI1 removal. Reduction of ARGs and intI1 was improved by increasing coagulants' doses: abundances of residual ARGs under optimal dose conditions were similar, regardless of the different characteristics of coagulant types. The strongly positive correlation between reduction of turbidity/total phosphorus (T-P) and ARGs was explored, identifying that turbidity or T-P might be suitable indicators linked with variations in the abundance of ARGs during CEPT. As a result, CEPT may prove promising in efforts to control ARGs flowing into a WWTP.

Intra-day microplastic variations in wastewater: A case study of a sewage treatment plant in Hong Kong

Wastewater treatment plants (WWTPs) in coastal region play a primary role in transferring microplastics into the marine environment. Wastewater is closely related to anthropogenic activities, thus the intra-day variation of abundance of microplastics in the influent should be large and could have significant impact on their estimation of the daily mass load. In this study, a 2-hour interval sampling campaign was conducted at a secondary WWTP in Hong Kong to investigate the intra-day variations and daily loads of microplastics in influent. Results show that the average microplastic abundances increased from 7.1 ± 6.0 to 12.8 ± 5.8 particles/L over time, with predominant particle sizes ranging 1-5 mm. Approximately 80% of the microplastics in samples collected from 9:30-15:00 were polyethylene and polyester, while most samples collected at 17:00 were polypropylene and polyurethane. Microplastic loads exhibited large intra-day variations ranging 6.60 × 10⁸-1.16 × 10⁹ particles/day, indicating that calculated daily microplastic loads based on a specific sampling period may inaccurately estimate the actual daily load.

Optimized fuzzy inference system to enhance prediction accuracy for influent characteristics of a sewage treatment plant

Sewage treatment plants (STPs) keep sewage contamination within safe levels and minimize the risk of environmental disasters. To achieve optimum operation of an STP, it is necessary for influent parameters to be measured or estimated precisely. In this research, six well-known influent chemical and biological characteristics, i.e., biochemical oxygen demand (BOD), chemical oxygen demand (COD), Ammoniacal Nitrogen (NH₃-N), pH, oil and grease (OG) and suspended solids (SS), were modeled and predicted using the Sugeno fuzzy logic model. The membership function range of the fuzzy model was optimized by ANFIS, the integrated Genetic algorithms (GA), and the integrated particle swarm optimization (PSO) algorithms. The results were evaluated by different indices to find the accuracy of each algorithm. To ensure prediction accuracy, outliers in the predicted data were found and replaced with reasonable values. The results showed that both integrated GA-FIS and PSO-FIS algorithms performed at almost the same level and both had fewer errors than ANFIS. As the GA-FIS algorithm predicts BOD with fewer errors than PSO-FIS and the aim of this study is to provide an accurate prediction of missing data, GA-FIS was only used to predict the BOD parameter; the other parameters were predicted by PSO-FIS algorithm. As a result, the model successfully could provide outstanding performance for predicting the BOD, COD, NH₃-N, OG, pH and SS with MAE equal to 3.79, 5.14, 0.4, 0.27, 0.02, and 3.16, respectively.

Per capita loads of organic UV filters in Australian wastewater influent

Per capita loads of six UV filters were estimated in wastewater influent samples from 36 wastewater treatment plants in Australia collected over a weekend period during the 2016 Australian Census. Of the analysed samples, 99% contained at least one of the target compounds. Phenyl benzimidazole sulfonic acid (PBSA) was the most prevalent (99%), followed by benzophenone 4 (BP4) (97%), benzophenone 3 (BP3) (87%), benzophenone 1 (BP1) (84%), 4-methylbenzylidene camphor (4-MBC) (22%) and isoamyl 4-methoxycinnamate (IMC) (1.5%). The highest concentrations were 3780 and 5070 ng L^-1 for PBSA and BP4, respectively. Total per capita UV filter loads in influent across all plants were calculated using population data from the Australian Census and ranged from 0.21 to 3.4 mg day^-1 person^-1. Notably, a relationship was found between latitude and total per capita daily mass load of UV filters with an increase in mass load from southern to northern catchments. Compared to international studies, mass loads were generally similar with higher loads of BP4 found in Australia. This study provides insight into the occurrence of UV filters in influent wastewater from across Australia and provides the first comprehensive nationwide baseline of UV filter loads.

A National Wastewater Monitoring Program for a better understanding of public health: A case study using the Australian Census

Wastewater contains a large range of biological and chemical markers of human activity and exposures. Through systematic collection and analysis of these markers within wastewater samples it is possible to measure the public health of whole populations. The analysis of effluent and biosolids can also be used to understand the release of chemicals from wastewater treatment plants into the environment. Wastewater analysis and comparison with catchment specific data (e.g. demographics) however remains largely unexplored. This manuscript describes a national wastewater monitoring study that combines influent, effluent and biosolids sampling with the Australian Census. An archiving program allows estimation of per capita exposure to and consumption of chemicals, public health information, as well as per capita release of chemicals into the environment. The paper discusses the study concept, critical steps in setting up a coordinated national approach and key logistical and other considerations with a focus on lessons learnt and future applications. The unique combination of archived samples, analytical data and associated census-derived population data will provide a baseline dataset that has wide and potentially increasing applications across many disciplines that include public health, epidemiology, criminology, toxicology and sociology.

Profiling the diversity of Cryptosporidium species and genotypes in wastewater treatment plants in Australia using next generation sequencing

Wastewater recycling is an increasingly popular option in worldwide to reduce pressure on water supplies due to population growth and climate change. Cryptosporidium spp. are among the most common parasites found in wastewater and understanding the prevalence of human-infectious species is essential for accurate quantitative microbial risk assessment (QMRA) and cost-effective management of wastewater. The present study conducted next generation sequencing (NGS) to determine the prevalence and diversity of Cryptosporidium species in 730 raw influent samples from 25 Australian wastewater treatment plants (WWTPs) across three states: New South Wales (NSW), Queensland (QLD) and Western Australia (WA), between 2014 and 2015. All samples were screened for the presence of Cryptosporidium at the 18S rRNA (18S) locus using quantitative PCR (qPCR), oocyst numbers were determined directly from the qPCR data using DNA standards calibrated by droplet digital PCR, and positives were characterized using NGS of 18S amplicons. Positives were also screened using C. parvum and C. hominis specific qPCRs. The overall Cryptosporidium prevalence was 11.4% (83/730): 14.3% (3/21) in NSW; 10.8% (51/470) in QLD; and 12.1% (29/239) in WA. A total of 17 Cryptosporidium species and six genotypes were detected by NGS. In NSW, C. hominis and Cryptosporidium rat genotype III were the most prevalent species (9.5% each). In QLD, C. galli, C. muris and C. parvum were the three most prevalent species (7.7%, 5.7%, and 4.5%, respectively), while in WA, C. meleagridis was the most prevalent species (6.3%). The oocyst load/Litre ranged from 70 to 18,055 oocysts/L (overall mean of 3426 oocysts/L: 4746 oocysts/L in NSW; 3578 oocysts/L in QLD; and 3292 oocysts/L in WA). NGS-based profiling demonstrated that Cryptosporidium is prevalent in the raw influent across Australia and revealed a large diversity of Cryptosporidium species and genotypes, which indicates the potential contribution of livestock, wildlife and birds to wastewater contamination.

Treatment characteristics of microplastics at biological sewage treatment facilities in Korea

Microplastics that are contained in household dust, personal care products, and other factors, are discharged into sewage treatment facilities (STF). While these microplastics are treated at the STF with a high treatment efficiency through settling, precipitation, filtering, and other treatments, considering the large amount of effluent, large quantities of microplastics are still discharged into marine environments. In this study, biological STF using the anaerobic-anoxic-aerobic (A2O), sequence batch reactor (SBR), and the Media processes were investigated to confirm the efficiency of these treatments and the associated amounts of microplastics released for each process. The three investigated processes were found to have treatment efficiencies of about 98% or more. However, due to the large amount of effluent, more than four billion pieces of microplastic were released each year in each facility. Thus, even though biological STF show high treatment efficiencies, substantially large amounts of microplastics are still released into the marine environment.

Data on assessment of physical, chemical and biological characteristics of effluent from wastewater treatment in Torbat Heydarieh, Iran

Data on the chemical, physical and biological of effluent from wastewater treatment are provided in table format in the current article. Samples were taken in Peak Flows at effluent Treatment Plants. Sampling and tests were conducted according to the standards methods. The collected data were analyzed by SPSS software and excel program. Nickel metal showed higher amounts than the standards required for irrigation agricultural land. Data could be useful from environmental and agricultural sciences to those concerned about heavy metals, Alkalinity, EC, COD, BOD₅ and Microbial concentrations threats.

Analysing the accuracy of machine learning techniques to develop an integrated influent time series model: case study of a sewage treatment plant, Malaysia

The function of a sewage treatment plant is to treat the sewage to acceptable standards before being discharged into the receiving waters. To design and operate such plants, it is necessary to measure and predict the influent flow rate. In this research, the influent flow rate of a sewage treatment plant (STP) was modelled and predicted by autoregressive integrated moving average (ARIMA), nonlinear autoregressive network (NAR) and support vector machine (SVM) regression time series algorithms. To evaluate the models' accuracy, the root mean square error (RMSE) and coefficient of determination (R²) were calculated as initial assessment measures, while relative error (RE), peak flow criterion (PFC) and low flow criterion (LFC) were calculated as final evaluation measures to demonstrate the detailed accuracy of the selected models. An integrated model was developed based on the individual models' prediction ability for low, average and peak flow. An initial assessment of the results showed that the ARIMA model was the least accurate and the NAR model was the most accurate. The RE results also prove that the SVM model's frequency of errors above 10% or below - 10% was greater than the NAR model's. The influent was also forecasted up to 44 weeks ahead by both models. The graphical results indicate that the NAR model made better predictions than the SVM model. The final evaluation of NAR and SVM demonstrated that SVM made better predictions at peak flow and NAR fit well for low and average inflow ranges. The integrated model developed includes the NAR model for low and average influent and the SVM model for peak inflow.

Data on pollutants content in the influent and effluent from wastewater treatment plant of Rasht in Guilan Province, Iran

Data on this paper show the concentrations of COD, BOD₅, TSS, K⁺, Ca²⁺, Na⁺, Cl^-, [Formula: see text], [Formula: see text], Mn²⁺, Fe²⁺, Mg²⁺, Zn²⁺, Ni, Pb, Cu and Cd in the influent and effluent of wastewater, and also the nematode eggs, total and fecal coliform in effluents from wastewater treatment plant of Rasht, Guilan Province, in Iran. Measurements of pollutants in influent and effluent was measured according to standard methods (W.E. Federation and Association, A. P. H., 2005) [1]. Statistical analysis of the data was carried out using Special Package for Social Sciences (SPSS 16).

Occurrence, removal, and risk assessment of antibiotics in 12 wastewater treatment plants from Dalian, China

In this study, the occurrence and removal efficiencies of 31 antibiotics, including 11 sulfonamides (SAs), five fluoroquinolones (FQs), four macrolides (MLs), four tetracyclines (TCs), three chloramphenicols (CAPs), and four other antibiotics (Others), were investigated in 12 municipal wastewater treatment plants (WWTPs) in Dalian, China. A total of 29 antibiotics were detected in wastewater samples with the concentration ranging from 63.6 to 5404.6 ng/L. FQs and SAs were the most abundant antibiotic classes in most wastewater samples, accounting for 42.2 and 23.9% of total antibiotic concentrations, respectively, followed by TCs (16.0%) and MLs (14.8%). Sulfamethoxazole, erythromycin, clarithromycin, azithromycin, ofloxacin, and norfloxacin were the most frequently detected antibiotics; of these, the concentration of ofloxacin was the highest in most of influent (average concentration = 609.8 ng/L) and effluent (average concentration = 253.4 ng/L) samples. The removal efficiencies varied among WWTPs in the range of -189.9% (clarithromycin) to 100% (enoxacin, doxycycline, etc), and more than 50% of antibiotics could not be efficiently removed with the removal efficiency less than 65%. An environmental risk assessment was also performed in the WWTP effluents by calculating the risk quotient (RQ), and high RQ values (>1) indicated erythromycin and clarithromycin might cause the ecological risk on organisms in surrounding water near discharge point of WWTPs in this area, which warrants further attention.

Occurrence of Cryptosporidium and Giardia in raw and finished drinking water in north-eastern Spain

This paper collects the first large-sample-size study on the presence of Cryptosporidium oocysts and Giardia cysts in drinking water plants at the 20 most populated towns in Aragón (north-eastern Spain). Samples of influent raw water and effluent finished water were collected from each plant during different seasons and processed according to USEPA Method 1623. Cryptosporidium oocysts and Giardia cysts were detected in samples collected from 55% and 70% plants, respectively, with nine plants being positive for both protozoa and only four plants being negative over the study period. Both parasites were identified in the raw water throughout the year, with a lower frequency in autumn and a peak in winter, at a mean concentration of 67±38 oocysts per 100l and 125±241 cysts per 100l. The turbidity of raw water was not related to the presence or concentration of (oo)cysts, and the (oo)cyst removal efficiency was not related to the type of water treatment. One or both pathogens were identified in the finished water in 7 out of 11 plants with a conventional treatment process (coagulation, flocculation, sedimentation, filtration, and disinfection processes) compared to 4 out of 9 plants that did not apply one of the pre-chlorination treatment steps. Protozoa were detected in the finished water of positive plants at a mean concentration of 88±55 oocysts per 100l and 37±41 cysts per 100l, and most of them excluded propidium iodide so were considered potentially viable. The ubiquity of these parasites in the drinking water sources and the inefficiency of conventional water treatment in reducing/inactivating them may present a serious public health issue in this geographical area.

Evaluation of a battery of marine species-based bioassays against raw and treated municipal wastewaters

The present study evaluates a battery of marine species-based bioassays against chemically characterized municipal wastewater samples (raw and WWTP treated). We estimated Dunaliella tertiolecta growth rate inhibition (24-96h IC₅₀ values), Artemia franciscana immobilization (24h LC₅₀ values), mussel hemocytes viability and lipid peroxidation enhancement (in terms of neutral red retention assay/NRRT and malondialdehyde/MDA content, respectively) in influent- and WWTP effluent-treated species. We found algal growth arrest and stimulation respectively, almost similar 24hLC₅₀ values in Artemia sp., and significantly higher adverse effects (in terms of NRRT and MDA levels) in influent-treated mussel hemocytes. Furthermore, the estimation of hatchability, yolk-sac larvae mortality (24-120hLC₅₀) and spinal deformities (SD) in sea bream Sparus aurata showed slight variations over time, with the lowest LC₅₀ and SD₅₀ (representing spinal deformities at 50% of yolk-sac larvae) values to be observed in influent-treated larvae at 120h. Data interpretation (both chemical and biological) revealed that toxic endpoints, such as NRRT₅₀, 96hIC₅₀Dun, 120hLC₅₀Sparus and 120hSD₅₀Sparus, significantly related to WWTP removal efficiency and further mediated by the presence of dominant compounds, such as As and Cr, could be used for identifying main components of toxicity in wastewaters.

Fate of antibiotic resistant cultivable heterotrophic bacteria and antibiotic resistance genes in wastewater treatment processes

Antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) are emerging contaminants of environmental concern. Heterotrophic bacteria in activated sludge have an important role in wastewater treatment plants (WWTPs). However, the fate of cultivable heterotrophic ARB and ARGs in WWPTs process remains unclear. In the present study, we investigated the antibiotic-resistant phenotypes of cultivable heterotrophic bacteria from influent and effluent water of three WWTPs and analysed thirteen ARGs in ARB and in activated sludge from anoxic, anaerobic and aerobic compartments. From each influent or effluent sample of the three plants, 200 isolates were randomly tested for susceptibility to 12 antibiotics. In these samples, between 5% and 64% isolates showed resistance to >9 antibiotics and the proportion of >9-drug-resistant bacteria was lower in isolates from effluent than from influent. Eighteen genera were identified in 188 isolates from influent (n=94) and effluent (n=94) of one WWTP. Six genera (Aeromonas, Bacillus, Lysinibacillus, Microbacterium, Providencia, and Staphylococcus) were detected in both influent and effluent samples. Gram-negative and -positive isolates dominated in influent and effluent, respectively. The 13 tetracycline-, sulphonamide-, streptomycin- and β-lactam-resistance genes were detected at a higher frequency in ARB from influent than from effluent, except for sulA and CTX-M, while in general, the abundances of ARGs in activated sludge from two of the three plants were higher in aerobic compartments than in anoxic ones, indicating abundant ARGs exit in the excess sledges and/or in uncultivable bacteria. These findings may be useful for elucidating the effect of WWTP on ARB and ARGs.

Seasonal changes in antibiotics, antidepressants/psychiatric drugs, antihistamines and lipid regulators in a wastewater treatment plant

Seasonal changes in the concentration of 21 pharmaceuticals in a wastewater treatment plant (WWTP) in České Budějovice were investigated over 12months. The target compounds were 10 antibiotics, 4 antidepressants, 3 psychiatric drugs, 2 antihistamines and 2 lipid regulators. 272 Wastewater samples (136 influents and 136 effluents) were collected from March 2011 to February 2012 and analyzed using two-dimensional liquid chromatography coupled with tandem mass spectrometry. All studied pharmaceuticals were frequently detected in both the influent and the effluent wastewater samples, except for meclozine, which was only found in the influent. The mean concentration of pharmaceuticals varied from 0.006μgL(-1) to 1.48μgL(-1) in the influent and from 0.003μgL(-1) to 0.93μgL(-1) in the effluent. The concentration of most pharmaceuticals was higher during winter.