Influent Water Research Articles

Metagenomic Profiling of Pathogens in Simulated Reclaimed Water Distribution Systems Operated at Elevated Temperature Reveals Distinct Response of Mycobacteria to Filtration and Disinfection Conditions

Distribution of reclaimed water presents distinct challenges for pathogen control relative to the distribution of conventional potable water. The elevated temperatures common in arid regions can exacerbate such challenges by accelerating disinfectant decay and increasing microbial growth rates. Here, we carried out a controlled, continuous-flow, head-to-head study of six simulated reclaimed water distribution systems (RWDSs) in order to assess whether treatments identified to be effective for microbiological control at a lower temperature (22 °C) were also effective at 30 °C. Shotgun metagenomic sequencing was carried out to comprehensively profile fecal pathogens (FPs) (e.g., Escherichia and Klebsiella spp.), non-FPs (non-FPs) (e.g., Legionella and Mycobacterium spp.), and antibiotic-resistance genes (ARGs). Consistent with prior studies, generally, all FP, non-FP, and ARG markers were lowest when the influent water was biologically active carbon (BAC) filtered and disinfected. However, in contrast to observations at the lower temperature, where BAC filtration combined with chlorine disinfection effectively controlled Mycobacterium spp., they were markedly elevated in BAC-filtered and chlorine- or chloramine-disinfected conditions. This study highlights the need for further research to improve the understanding of conditions that select for different mycobacterial species and identify strategies to effectively control them in RWDSs under elevated temperature conditions.

Carbon Reduction and Pollutant Abatement by a Bio-Ecological Combined Process for Rural Sewage.

In order to explore the treatment effect of a bio-ecological combined process on pollution reduction and carbon abatement of rural domestic wastewater under seasonal changes, the rural area of Lingui District, Guilin City, Guangxi Province, China was selected to construct a combined process of regulating a pond, biological filter, subsurface flow constructed wetland, and ecological purification pond. The influent water, effluent water, and the characteristics of pollutant treatment in each unit were investigated. The results showed that the average removal rates of COD, TN, and NH3-N in summer were 87.57, 72.18, and 80.98%, respectively, while they were 77.46, 57.52, and 64.48% in winter. There were significant seasonal differences in wastewater treatment results in Guilin. Meanwhile, in view of the low carbon:nitrogen ratio in the influent and the poor decontamination effect, the method of adding additional carbon sources such as sludge fermentation and rice straw is proposed to strengthen resource utilization and achieve carbon reduction and emission reduction. The treatment effect of ecological units, especially constructed wetland units, had a high contribution rate of TN treatment, but it was greatly impacted by seasons. The analysis of the relative abundance of the microbial community at the phylum level in constructed wetlands revealed that Proteobacteria, Acidobacteria, Chloroflexi, Firmicutes, Bacteroidetes, Planctomycetota, and Actinobacteria were the dominant phyla. The relative abundance of microbial communities of Proteobacteria, Chloroflexi, and Acidobacteria decreased to a large extent from summer to winter, while Firmicutes, Bacteroidetes, and Planctomycetota increased to varying degrees. These dominant bacteria played an important role in the degradation of pollutants such as COD, NH3-N, and TN in wetland systems.

Determination of Bisphenol A and Phthalate Levels in Wastewater Samples

Objective: The use of endocrine-disrupting chemicals (EDCs) such as bisphenol A (BPA) in plastics manufacturing, agriculture, livestock, and paint manufacturing increas daily. The water treated in wastewater treatment plants is used in many areas such as irrigation of parks and gardens, and reinforcement of underground water resources. However, whether the treatment process eliminates EDCs in wastewater is not exactly known, and determining this as well as the amounts of these chemicals in treated water are important in terms of protecting the environment and human health. The aim of the study was to determine BPA and phthalate concentrations in the influent and effluent flow samples obtained from wastewater treatment plants. Materials and Methods: BPA and phthalate concentrations were measured in influent and effluent flow samples using the enzymelinked immunosorbent assay (ELISA) method. BPA and phthalate measurements were performed as competitive measurements of BPA and total phthalates in samples using specific monoclonal antibodies. Results: BPA and phthalate levels were measured respectively as 7.69 μg/L and 78.27 μg/L in the influent water samples and 3.17 μg/L and 25.56 μg/L in the effluent water samples. The concentration of BPA and phthalates in the effluent samples decreased significantly compared to the influent water samples. Conclusion: This study is believed to shed light on the importance of monitoring BPA and phthalate concentrations in wastewater treatment plants and inspections for detecting other EDCs in wastewater.

Performance of Constructed Wetland on the Removal of Nutrient in Domestic Wastewater Using Chrysopogon Zizanioides

In this study, a native wild plant, Chrysopogon zizanioides (C-zi), was used in a wetland system to treat household wastewater. The root system of the C-zi is comprised of primary roots, secondary roots, and filamentous roots that all extend vertically deep into the soil rather than spreading horizontally. Depending on the concentration of the influent water, the water entering the vetiver-containing tank was stored for 3 to 5 days. These results demonstrated C-superior zi's ability to degrade organic waste as well as nutrients. COD, BOD, phosphorus, and ammonia are all removed with a high degree of effectiveness (82%, 82%, 80%, and 76%, respectively) in both stages of domestic wastewater treatment. The plant's roots had grown from 5 to 30 centimeters in length over the course of three months. In aspects of wastewater treatment and high biomass growth in wetland system, it was proposed that the use of C-zi is favorable.

Lake management under severe drought: Lake Mead, Nevada/Arizona

AbstractDrought can affect both the quantity and quality of water in lakes and reservoirs, yet larger, highly managed waterbodies, such as Lake Mead, may be somewhat buffered from drought effects. From 2000 to present, Lake Mead has experienced a 71% decline in volume; however, influent water quality has remained high and consistent outflow volumes through Hoover Dam have been maintained. Furthermore, management activities, such as increased removal of phosphorus by wastewater dischargers and legacy contamination cleanup efforts, have been initiated since the drought began. These efforts have led to small improvements in values of water quality parameters, such as phosphorus, nitrogen, and perchlorate, despite loss of volume for dilution of constituents, and consequently, decreased residence time. As the drought continues, Lake Mead is projected to continue declining in volume, inflows are projected to become warmer, and the population of Las Vegas is projected to grow, potentially adding additional stress to the hydrologic system. Maintenance of outflow may mitigate some potentially negative consequences, and understanding the drivers behind continued high water quality despite prolonged drought is important to continue to maintain the health and vitality of the entire Lower Colorado River Basin.

The coexistence of copper ions and TC affected the binding ability and the reaction order between extracellular polymeric substances of aerobic granular sludge and exogenous substances.

As a barrier against external toxic effects, extracellular polymeric substances (EPSs) directly affect the toxicity and removal efficiency of exogenous substances. The reaction of EPSs with exogenous substances has been taken into consideration. The contents of EPSs in sludge cultivated by different influent water vary greatly, which leads to great differences in the binding ability and reaction sequence between EPSs and exogenous substances. However, the results in this respect are very limited. In this study, the binding characteristics between exogenous tetracycline (TC)/copper ions (Cu2+) and EPSs from aerobic granular sludge cultured under single and coexisting TC/Cu2+ were assessed by three-dimensional fluorescence-parallel factor analysis. The pollutants in the influent water could directionally induce microorganisms to secrete more EPSs, while fluorescence substances in EPSs could combine with the exogenous substances to lessen their effects. In the presence of coexisting TC and Cu2+ in the influent water, the ability of fluorescence substances in EPSs to combine with exogenous TC or Cu2+ weakened, and humic substances in EPSs were more susceptible than protein substances to binding with exogenous substances. However, the reaction order between EPSs components and exogenous TC or Cu2+ was opposite, and the ability of fluorescence substances in EPSs to combine with exogenous TC or Cu2+ was enhanced under individual TC or Cu2+ existing in the influent water. This study provided new insights into the interaction between EPSs and exogenous substances.

Compact fluidic electrochemical sensor platform for on-line monitoring of chemical oxygen demand in urban wastewater

• Carbon-silica (C/SiO 2 ) thin films produced by sol–gel chemistry. • C/SiO 2 electrode fabrication at wafer-scale by photolithography / etching process. • Excellent electrochemical performance shown by the fabricated electrodes. • Electrochemical sensor integrated in a modular fluidic system for in-field use. • Cu NPs-modified C/SiO 2 sensor used for on-line analysis of COD in urban wastewater. The rapid expansion of urban areas has given rise to the generation of large amounts of wastewater that pose a growing pressure on the surrounding ecosystems. Effective water quality surveillance programs demand the implementation of in-field tests to monitor water safe discharge in the environment after being adequately treated. This paper describes the manufacturing and application of a miniaturized electrochemical sensor for measuring dissolved chemical oxygen demand (COD) in surface waters entering and exiting urban wastewater treatment plants (UWWTP). Thin-film carbon electrodes are produced on Si/SiO 2 substrates by a combined sol–gel material synthesis and photolithography/dry etching process at the wafer level and show superior electrochemical performance compared with the glassy carbon standard electrode. Three-electrode electrochemical cells of planar configuration are produced and the COD sensor is manufactured by electrodepositing copper nanoparticles (Cu NPs) on the working electrode under controlled potentiostatic conditions. A simple fluidic electrochemical sensor device is fabricated and allows for the Cu NPs electrodeposition as well as analytical sensor performance in an automatic fashion. A linear range up to 670 mg·L -1 O 2 and a limit of detection of 30 mg·L -1 O 2 are achieved. The ability of this electrochemical sensor approach to monitoring the soluble organic load of urban wastewater in real-time is evaluated by analyzing three samples collected in different locations of an UWWTP. The COD values estimated with the sensor are in excellent agreement with those obtained using the standard dichromate method provided by an accredited laboratory. This analytical platform provides a robust, user-friendly low-maintenance flow sensor approach for deployed analysis of COD that could aid to control the effectiveness of water treatment processes, especially when facing water influents containing organic overloads due to changing weather conditions or any anthropogenic phenomena.

Inhibition and recovery of ANAMMOX with Na2SO3: From performance to microbial community analysis

In this study, three concentrations of Na2SO3 solution were used to remove dissolved oxygen in the influent water and enter the up-flow anaerobic sludge bed reactor (UASB). This study investigated the effects of three concentrations of Na2SO3 on the inhibition and performance recovery of the ANAMMOX system and the structure of the microbial community. The results showed that although Na2SO3 had a deoxidizing function, the ANAMMOX system underwent a sulfate reduction reaction after adding Na2SO3, and the reduction product was mainly H2S, which caused the AnAOB to be inhibited by sulfide. The denitrification performance was less than 1/2 of that under normal conditions. The ANAMMOX system was restored by immediately removing Na2SO3 and reducing nitrogen load. After 11, 20, and 34 days, the performance of the ANAMMOX system returned to normal, but low concentrations(45 mg/L) required a long recovery time. High-throughput sequencing analysis showed that the community of the ANAMMOX system changed significantly. Before and after the experiment, the relative abundance of ANAMMOX functional bacteria Candidatus Brocadia decreased from 32.66% to 21.4%, and Candidatus Kuenenia decreased from 7.3% to 4.06%. However, the relative abundances of Armatimonadetes and Ignavibacteriae increased from below 2% to about 20%. At the same time, Thiobacillus and Desulfuromonadales were observed. This paper explores and summarizes the cause of Na2SO3's inhibition of AnAOB, highlights the recovery of AnAOB after inhibition for the stable operation and deepens the understanding of the environmental conditions regulating the ANAMMOX process.

Long-term variation characteristics of nutrients in the water and sediments of a surface flow constructed wetland with micro-polluted water sources

This study aimed to evaluate the long-term effects of a large-scale constructed wetland purifying micro-polluted water and explore accumulation characteristics and influencing factors of nutrients in sediments. For this purpose, the water quality and nutrients in sediments of the long-running large-scale constructed wetland of Yanlong Lake were monitored for eight years since the wetland began operation. The results demonstrated that the average removal rates of permanganate index (CODMn), ammonia nitrogen (NH4+-N), total nitrogen (TN) and total phosphorus (TP) were 4.39 ± 12.64%, 41.57 ± 16.36%, 32.61 ± 23.36% and 47.05 ± 20.39% in the constructed wetland from 2013 to 2020, respectively. The CODMn removal effects were the lowest. Sediments of the constructed wetland were moderately polluted and the cumulative level of nutrients was mainly affected by the organic matter content, influent water quality, water depth and plant function. Firstly, TN and TP in sediments are significantly positively correlated with total organic carbon. Besides, the nutrient concentrations in sediments increased along the water flow direction. Furthermore, the nutrient concentrations in sediments increased with water depth, and the carbon was greatly affected. In addition, the overgrowth and lodging of wetland plants could promote the nutrients accumulation in sediments. This research results provide a scientific basis for improving the purification capacity of long-running surface flow constructed wetlands.

Simultaneous trace determination of three natural estrogens and their sulfate and glucuronide conjugates in municipal waste and river water samples with UPLC-MS/MS.

Analytical method for three natural estrogens (NEs) and their sulfate and glucuronide conjugates in waste and river waters using solid-phase extraction (SPE) coupled with ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) has been available, but problems including poor recovery exist. In order to solve these, some optimizations have been performed in this work. For sample preparation, both rinse and elution solutions were optimized, in which 6mL of MeOH/water (1:9, v/v), MeOH/Ace/water (10:2:88, v/v/v), and MeOH/NH4OH/water (10:2:88, v/v/v) were determined as the rinse solution, while 6mL of 2.0% NH4OH/MeOH was determined as the elution solution for conjugated NEs (C-NEs). For mobile phase, addition of NH4F could obviously enhance the signal response of the nine target compounds, and the optimized addition concentration was 0.5mmol/L. The developed efficient method was validated and showed excellent linearity for each target compound (R2 > 0.998), low limit of quantifications (LOQs, 0.07-1.29ng/L) in four different water matrices, and excellent recovery efficiencies of 81.0-116.1% in influent, effluent, ultra-pure, and river water samples with low relative standard deviations (RSDs, 0.6-13.6%). The optimized method was successfully applied to influent, effluent, and Pearl River water, among which three NEs were all detected, while five C-NEs were found in the influent, three C-NEs were detected in the effluent, and two C-NEs were found in the Pearl River water, indicating the wide distribution of NEs and C-NEs in different water environments. This work provided a reliable and efficient analytical method for simultaneous trace determination of NEs and C-NEs, which had satisfactory absolute recoveries with low RSDs, low LOQs, and time-saving for both analysis and nitrogen drying.

Assessing the Fate of Dissolved Organic Compounds in Landfill Leachate and Wastewater Treatment Systems.

Landfill leachate and municipal wastewater are major sources of chemical pollutants that contaminate our drinking water sources. Evaluating the dissolved organic chemical composition in wastewater treatment plants is therefore essential to understand how the discharge impacts the environment, wildlife, and human health. In this study, we utilized a nontargeted analysis method coupling liquid chromatography and tandem mass spectrometry (LC-MS/MS) to analyze chemical features at different points along two landfill leachate treatment plants (LLTPs) and two municipal wastewater treatment plants (WWTPs) in the Southeastern United States. Significant feature differences were observed for the WWTPs where activated sludge clarification was employed versus the LLTPs utilizing reverse osmosis. Specifically, even though both LLTPs had the largest number of features in their influent water, their effluent following reverse osmosis yielded a lower number of features than the WWTPs. Additionally, the clarification processes of each WWTP exhibited different efficiencies as chemical disinfection removed more features than UV disinfection. Feature identification was then made using the LC, MS, and MS/MS information. Analysis of the identified molecules showed that lipids were the most effectively removed from all plants, while alkaloid and organic nitrogen compounds were the most recalcitrant.

Comparison of anthracite and GAC biofilter performance for surface‐water manganese removal

AbstractAlameda County Water District has observed increased biofilter effluent manganese concentrations during winter operations. To investigate manganese removal across surface water biofilters during cold‐water conditions, trends were analyzed between water temperature and manganese removal across multiple testing scales, multiple biofilter influent water qualities, and both anthracite and GAC media. During acclimation of new biofilters, 100% removal of manganese was observed sooner across both anthracite and GAC biofilters brought online at 20°C compared to 12°C. Acclimation at 12°C required 18 extra days for the GAC biofilters and 48 additional days for the anthracite biofilters. For fully acclimated biofilters, a decrease in manganese removal across both GAC and anthracite biofilters at temperatures below 15°C was observed. However, greater and more consistent manganese removal was observed across GAC compared to anthracite biofilters. Performance differences between locations also suggest that operational and water quality conditions also likely affect manganese removal.

Mass quantification of microplastic at wastewater treatment plants by pyrolysis-gas chromatography–mass spectrometry

Municipal wastewater treatment plants (WWTPs) are a central point of collection of plastic particles from households and industry and for their re-distribution into the environment. Existing studies evaluating levels of plastics in WWTPs, and their removal rates have reported and used data on polymer type, size, shape, colour, and number of plastic particles, while the total mass concentration of plastic particles (especially >1 μm) remains unclear and unknown. To address this knowledge gap, raw influent, effluent, and reference water samples from three WWTPs in Australia were collected to analyse the mass concentrations and removal rates of seven common plastics (>1 μm in size) across the treatment schemes. Quantitative analysis was performed by pressurized liquid extraction followed by pyrolysis coupled to gas chromatography mass spectrometry. Results showed that the total plastic content in the WWTPs raw influent samples was between 840 and 3116 μg/L, resulting in an inflow of between about 2.1 and 196.4 kg/day of the total measured plastics. Overall, >99 % by mass of the plastics entering the three WWTPs from the raw influent was removed during the pre-treatment stages, presumably ending up in the sewage sludge, which means emissions (via treated effluent) from the treatment plants are low. Compared with the raw influent, the plastic mass concentrations in the treated effluents (i.e., Class C, A, and final effluent) from the three WWTPs, as well as the reference water samples within their catchments were below the limits of reporting. Of the five quantified plastic types, polyethylene (PE, 76.4 %), and polyvinylchloride (PVC, 21 %) dominated by mass, while polyethylene terephthalate (PET, 1.9 %), polypropylene (PP, 0.4 %) and polymethyl methacrylate (PMMA, 0.3 %) accounted for a small proportion of the total. Overall, this study investigated the mass concentrations of plastic particles above 1 μm in wastewater and their removal, which provided valuable information regarding the pollution level and distribution characteristics of plastic polymers in Australian WWTPs.

Clean drinking water solution for rural India: Portable sip-up

Ceramic water filters (CWFs) have been used in India due to their low expense, ease of manufacture, and livelihood sustenance features. However, the use and throw character of such systems has not been achieved. The purpose of this study is to develop and investigate the portable CWF variant named Sip-up, which can be attached to any commercially available bottle-based containers. These are porous functional structures made of a distinct volume fraction combination of salty clay, sawdust, and marble powder wet mix, formed into cylindrical shapes and baked at 650°C. The influent and filtrate water samples were analyzed. After filtration, the pH, on average, significantly improves from 8.2 to 7.4. The TDS level, conductivity, and salt content have been reduced by 8.43%, 6.89%, and 5.83%, respectively, which conforms to the WHO limits. A 99% reduction of E. Coli bacteria through CWF was also observed. This portable water filter will be accessible to the people at the lowest economic pyramid.

Determining Toxic Potencies of Water-Soluble Contaminants in Wastewater Influents and Effluent Using Gene Expression Profiling in C. elegans as a Bioanalytical Tool

With chemical analysis, it is impossible to qualify and quantify the toxic potency of especially hydrophilic bioactive contaminants. In this study, we applied the nematode C. elegans as a model organism for detecting the toxic potency of whole influent wastewater samples. Gene expression in the nematode was used as bioanalytical tool to reveal the presence, type and potency of molecular pathways induced by 24-h exposure to wastewater from a hospital (H), nursing home (N), community (C), and influent (I) and treated effluent (E) from a local wastewater treatment plant. Exposure to influent water significantly altered expression of 464 genes, while only two genes were differentially expressed in nematodes treated with effluent. This indicates a significant decrease in bioactive pollutant-load after wastewater treatment. Surface water receiving the effluent did not induce any genes in exposed nematodes. A subset of 209 genes was differentially expressed in all untreated wastewaters, including cytochromes P450 and C-type lectins related to the nematode’s xenobiotic metabolism and immune response, respectively. Different subsets of genes responded to particular waste streams making them candidates to fingerprint-specific wastewater sources. This study shows that gene expression profiling in C. elegans can be used for mechanism-based identification of hydrophilic bioactive compounds and fingerprinting of specific wastewaters. More comprehensive than with chemical analysis, it can demonstrate the effective overall removal of bioactive compounds through wastewater treatment. This bioanalytical tool can also be applied in the process of identification of the bioactive compounds via a process of toxicity identification evaluation.Graphical abstract

Characterisation of aluminium industrial wastewater and investigation of recovery alternatives

Aluminium industry is one of the largest sectors and wastewater generated from this industry could cause crucial environmental problems due to its high heavy metal concentration and conductivity. Therefore, this study aims to determine the characterisation of the wastewater discharged from the two aluminium facilities by considering water recovery potential. While Facility-A produces stainless steel kitchenware, such as pots and pans, In Facility-B, anodised coating takes place from secondary aluminium and wastewater is generated from the units where anodised coating baths and control processes are carried out. For the analyses, the wastewater composite samples from different sections, such as washing, sand-blasting and dyeing in Facility-A were taken in 2 and 24 hours. In Facility-B, three 2-hour composite influent water samples and an effluent sample from chemical wastewater treatment were taken to determine conductivity, pH, chemical oxygen demand (COD), total suspended solids (TSS), etc. As a result of the analyses made, a high value of TSS was detected at all sampling points in Facility-A. It was also seen that the conductivity after demineralisation process in Facility-A was below 30. In Facility-B, it was determined that while the pH obtained from two influent samples was below the discharge limits and showed acidic characteristics, one sample was very basic with a pH value of 12.19 and exceeds the upper limit of discharge. All influent samples in Facility-B show high TSS content in comparison with discharge limits specified in the regulation.

Drinking water quality assessment according to water quality index and health risk assessment: а case study of Pedro Vicente Maldonado canton, Ecuador

The effluent water quality of a treatment plant in a canton of Ecuador according to water quality index (WQI) and health risk assessment was investigated in this study. The quality of the influent and effluent water of the treatment plant was monitored monthly from January 2017 to December 2019. Physicochemical and microbiological parameters, such as temperature, pH, turbidity, color, suspended solids, electrical conductivity, free chlorine, nitrates, nitrites, ammonia nitrogen, sulfates, fluorides, manganese, iron, fecal coliforms and total coliforms were determined. To evaluate the impacts of studied water on human health, health risk assessment for non-cancerogenic elements, including hazard index (HI) and risk of olfactory-reflex effects for organoleptic indicators were performed in accordance with Russian and foreign guidelines. Water quality parameter results were compared with WHO drinking water standards, revealing that the influent was contaminated microbiologically and other parameters such as color, turbidity, and iron were also above the limit values. The WQI results showed that water after purification is suitable for drinking (I class - excellent). Hazard Index (HI) results showed that the non-carcinogenic substances studied had a low risk for both adults and children (1). Additionally, the risk of olfactory-reflex effect was characterized as acceptable for all the collected purified water samples.

Improved neural network with least square support vector machine for wastewater treatment process

This research offers a unique interval by using the predicting approach for discharge indicators of water quality data such as biochemical oxygen demand (BOD) and ammonia nitrogen (NH3–N). This is considered one of the significant quality metrics in wastewater treatment plants for water quality management as well as surveillance. To begin, the effluent information for BOD/NH3–N and their supplementary parameters are gathered. Hence BOD and NH3 are considered major feature sources for estimating water pollutants. BOD is high then oxygen level is very low in the water due to pollutants or algae. Ammonia nitrogen is an organic waste component in water from sewage. The significant characteristics with good correlation levels of BOD and NH3–N are examined and identified using a grey correlation analysis method after certain basic data pre-processing procedures. The BOD/NH3–N effluent information of a water treatment plant is predicted using an upgraded feed-forward neural network with the least square support vector machine (FFNN-LSSVM) method. An optimization approach for an enhanced feed-forward neural network (IFFNN) is built by Machine Learning Algorithms. The IFFNN used regular influent water quality, influent rate of flow, and Wastewater performance monitoring and operational conditions as input parameters. For future prediction, input variables were previous different wastewater quality measurements. Lastly, the analysis shows that, when compared to other current algorithms, the proposed methodology can forecast wastewater quality of water with high accuracy in predicting BOD and NH3 levels, limited computation duration, mean error less than 10% and R2 is 90% proves better than existing techniques.

Antibiotics and antimycotics in waste water treatment plants: Concentrations, removal efficiency, spatial and temporal variations, prediction, and ecological risk assessment

For investigating the spatial, temporal variations and assessing ecological risk of 10 antibiotics and 6 antimycotics, influent sewage water and treated effluent were collected during three different seasons in 19 waste water treatment plants of Tianjin. High performance liquid chromatography tandem mass spectrometry was used to analyze 16 substances. The concentration range of influent samples was not detected (nd) −547.94 ng/L and the concentration range of effluent samples was nd–52.97 ng/L. By calculating the removal efficiency, it was found that Ciprofloxacin (CIP), Ofloxacin (OFL) and Clotrimazole (CTR) were effectively removed. There were significant spatial and temporal differences, the concentration in the dry season was evidently higher than that in the wet and normal seasons, and the northeast was lower than that in the northwest and southeast. By establishing a data set of influent and effluent, the priority features were extracted by feature engineering, which were temperature and NH3–N. Under the condition of ensuring the best performance of the models, the influent model with 9 features and the effluent model with 4 features were established, and the quantitative relationship between the above features and concentration was obtained through partial dependence analysis. Except for Moxifloxacin (MOX), Norfloxacin (NOR) and OFL in the influent samples, the RQ values for other antibiotics and antimycotics were less than 0.1. Among the effluent samples, only NOR had an RQ value greater than 0.1, and OFL, MOX, and Pefloxacin (PEF) had RQ values between 0.01 and 0.1. Comparing the observations and predictions individual RQ values, the predictions were ideal and matched the observations. This work effectively assessed environmental impact and provided a valuable reference for evaluating antibiotics and antimycotics ecological toxicity.

Efficiency of a multi-barrier household system for surface water treatment combining a household slow sand filter to a Mesita Azul® ultraviolet disinfection device

Low-cost household technologies for water treatment are crucial to improving drinking water quality and preventing health, social and economic impacts, mostly in middle- and low-income regions. This work assessed the removal efficiency of physical-chemical and bacteriological parameters from river water by a multi-barrier household water treatment system for 113 consecutive days. This system combines a pre-treatment step through a non-woven synthetic blanket, filtration by an intermittent household slow sand filter (HSSF) and a Mesita Azul® ultraviolet disinfection device. In general, the water quality was improved by the evaluated system. Turbidity was removed by an average of 73% (ranging from 33 to 94%), total coliforms (TC) of 3.88 log10 (ranging from 2.22 to 5.16 log10) and E. coli of 2.49 log10 (ranging from 1.81 to 3.30 log10). Filtration improvement was mostly correlated to HSSF biofilm development and influent water quality. Characterisation of HSSF schmutzdecke demonstrated a predominance of organic content, and a higher presence of carbohydrates than proteins on the sand and the blanket. Ultraviolet disinfection with Mesita Azul® inactivated most of the remaining bacteria after filtration and no regrowth was observed after 15 days of disinfection. In conclusion, the multi-barrier household water treatment system was efficient in treating river water, reducing risks of microbial contamination to achieve safe drinking water.