Domestic Wastewater Discharges Research Articles

Characterization and Proposal of Technologies for The Treatment of Domestic Sewage in Ilha Grande Bay – RJ

Objective: To characterize the situation of sanitary wastewater discharge in the hydrographic basins draining into the Baía da Ilha Grande (BIG) and to propose wastewater treatment alternatives based on the literature on decentralized solutions. Theoretical framework: The BIG has been experiencing negative environmental impacts due to the urbanization process in the region, mainly due to the irregular discharge of domestic wastewater into the environment. Method: The methodology was developed in two stages, with stage 1 involving data collection from available data in the 2017 Wastewater Atlas, and stage 2 focusing on identifying the most appropriate treatment technologies for this study from the fifteen options evaluated. Results and conclusion: The characterization revealed that municipalities within the BIG are already using decentralized solutions for domestic wastewater treatment, albeit below the national average coverage rates (18-54%). The five most promising technologies identified were Septic Tanks, Compact UASB, Biodigesters, Compartmentalized Anaerobic Reactors, and Integrated Biosystems. It is concluded that the communities have a sanitation deficit and show potential for implementing decentralized solutions. Implications of the research: The study helped develop strategies for decision-makers to select the most appropriate wastewater treatment technologies to meet local needs. It also served as a model for scientific studies in other locations. Originality/value: This study aligns with the Sustainable Development Goals (SDGs), particularly SDG 6, by presenting decentralized solutions as a promising pathway to universalizing household wastewater treatment in developing countries.

Evaluating Groundwater Quality Using Multivariate Statistical Analysis and Groundwater Quality Index

Under pressure from surface water pollution and climate change, groundwater becomes a critical water source. Information on groundwater quality could contribute to effective groundwater management. This study was carried out to utilize multivariate statistical analysis and the groundwater quality index (GWQI) to evaluate groundwater quality in Ca Mau Province, Vietnam. Twenty-five groundwater samples from residential-urban areas, cemetery areas, landfill areas, and saline intrusion areas were collected for this study. Groundwater quality was evaluated using the National Technical Regulation on Groundwater Quality (QCVN 09-MT:2015/BTNMT) and GWQI. Principal component analysis (PCA) was used to identify potential polluting sources and key variables influencing groundwater quality. Cluster analysis (CA) was applied to cluster groundwater quality, and the sites were recommended for future monitoring. The results revealed that NH4+-N contaminated groundwater in the landfill area, while the saline intrusion area was polluted by TDS and NH4+-N. The groundwater quality classified as excellent, good, poor, and very poor accounted for 44, 40%, 12%, and 4%, respectively. Cluster analysis divided groundwater quality into four groups, mainly based on the presence of NH4+-N and TDS. Nine groundwater sampling locations could be removed from the current groundwater quality program but still ensuring representativeness as a result of CA. PCA proposed two main sources of variation in groundwater quality at each residential-urban area: the cemetery area, the landfilling area, and the saline intrusion area. The groundwater parameters (i.e., pH, TDS, permanganate index, NH4+-N, NO3--N, and Fe) should be continued to monitor. Domestic and industrial wastewater discharge, leachate from cemeteries and landfills, the nature of groundwater aquifers, and seawater intrusion could be potential sources of groundwater variation. The current findings provide scientific information for local environmental authorities to manage and monitor groundwater quality in the study area. Doi: 10.28991/CEJ-2024-010-03-03 Full Text: PDF

Potential pathogenic microorganisms in rural wastewater treatment process: Succession characteristics, concentration variation, source exploration, and risk assessment

Pathogenic microorganisms can cause infection, sepsis, and other diseases in humans. Although municipal wastewater plants are important sources and sinks for potential pathogenic microorganisms, data on rural wastewater treatment processes are limited. The proximity of rural wastewater facilities to human settlements and the trend toward wastewater resourcing could pose risks to humans. Here, a typical village in southern China was selected to analyze potential pathogenic microorganisms in wastewater, sewage sludge, and aerosols during the collection, treatment, and discharge of domestic wastewater. The succession characteristics and concentration variations of potential pathogenic microorganisms throughout the wastewater treatment process were identified using high-throughput sequencing and culture methods. Bacteria-associated health risks in facility aerosols were estimated based on average daily dose rates from inhalation and dermal exposure. Lower amounts of pathogenic bacteria and pathogenic fungi were detected in the effluent of the 1-ton treatment scale and the 10-ton treatment scale facilities, compared to those in the influent. Pathogen effluent concentrations were significantly lower than influent concentrations after treatment in rural wastewater facilities. 16 and 29 potential pathogenic bacteria and fungi were detected in aerosols from wastewater treatment facilities, respectively. Furthermore, the potential pathogen concentrations were higher than those in the background air. Aerobic units are the main source of pathogen emissions from aerosols. There were 42 potential pathogenic bacteria and 34 potential pathogenic fungi in the sewage sludge. Biochemical units were the main source of potential pathogens in sewage sludge, and more potential airborne pathogens originated from wastewater. In rural wastewater resourcing processes with greater pollutant exposure, the effluent of rural wastewater treatment facilities (WWTFs), downstream rivers, and facility aerosols, could be important potential sources of microbial risk. Inhalation is the main pathway of human exposure to airborne bacteria. Therefore, more attention should be focused on microbiological risk in rural wastewater treatment processes.

High nutrient availability modulates photosynthetic performance and biochemical components of the economically important marine macroalga Kappaphycus alvarezii (Rhodophyta) in response to ocean acidification

Increased atmospheric CO2 concentrations not only change the components of inorganic carbon system in seawater, resulting in ocean acidification, but also lead to decreased seawater pH, resulting in ocean acidification. Consequently, increased inorganic carbon concentrations in seawater provide a sufficient carbon source for macroalgal photosynthesis and growth. Increased domestic sewage and industrial wastewater discharge into coastal areas has led to nutrient accumulation in coastal seawaters. Combined with elevated pCO2 (1200 ppmv), increased nutrient availability always stimulates the growth of non-calcifying macroalgae, such as red economical macroalga Gracilariopsis lemaneiformis. Here, we evaluated the interactive effects of nutrients with elevated pCO2 on the economically important marine macroalga Kappaphycus alvarezii (Rhodophyta) in a factorial 21-day coupling experiment. The effects of increased nutrient availability on photosynthesis and photosynthetic pigments of K. alvarezii were greater than those of pCO2 concentration. The highest Fv/Fm values (0.660 ± 0.019 and 0.666 ± 0.030, respectively) were obtained at 2 μmol L−1 of NO3–N at two pCO2 levels. Under the elevated pCO2 condition, the Chl-a content was lowest (0.007 ± 0.004 mg g−1) at 2 μmol L−1 of NO3–N and highest (0.024 ± 0.002 mg g−1) at 50 μmol L−1 of NO3–N. The phycocyanin content was highest (0.052 ± 0.012 mg g−1) at 150 μmol L−1 of NO3–N under elevated pCO2 condition. The malondialdehyde content declined from 32.025 ± 4.558 nmol g−1 to 26.660 ± 3.124 nmol g−1 with the increased nutrients at under low pCO2. To modulate suitable adjustments, soluble biochemical components such as soluble carbohydrate, soluble protein, free amino acids, and proline were abundantly secreted and were likely to protect the integrity of cellular structures under elevated nutrient availability. Our findings can serve as a reference for cultivation and bioremediation methods under future environmental conditions.

Monitoring subtropical aquatic ecosystems: evaluating the use of Trophic State Indices (TSI) and Aquatic Life Protection (API) as baseline indices by monitoring an urban reservoir in southeastern Brazil.

The use of indices is recommended for continuous monitoring and assessment of aquatic ecosystems, as they summarize the technical complexity of the results of multiple analyzes performed and translate these results into quality classes that reflect the actions taken and indicate ways to recover and conserve the resources. Environmental trophic state indices provide information on how nutrients, light availability and other factors promote the development of algal biomass and contribute to increased enrichment status of aquatic systems. Lamparelli's Trophic State Index (TSI) distinguishes between lentic (lower phytoplankton productivity) and lotic (higher phosphorus concentrations and lower chlorophyll-a concentrations) environments. The Aquatic Life Protection Index (ALPI) reflects water quality based on the trophic state of the environment, determines the degree of toxicity to biota and indicates deficiencies in variables and conditions essential for the protection of aquatic life. The indices were applied to a long data series to monitor the Guarapiranga Reservoir, an urban reservoir in the state of São Paulo in southeastern Brazil, which suffers from the urbanization of its surroundings and the discharge of domestic wastewater. The evaluation of the time series from 1978 to 2021 using these indices showed a deterioration in the trophic status and conservation of aquatic life in the reservoir and in one of its tributaries. Considering that the joint assessment of the two indices provides an approach to environmental conservation, their long-term use reflected changes and impacts on the environment and showed the best-preserved sites. Both indices are suitable for application in a baseline network in subtropical environments. They can pinpoint locations for better monitoring and are sensitive to environmental changes.

Assessment of the water quality of Lake Baikal and its tributaries in areas affected by local pollution based on microbiological and hydrochemical data

The water quality of Lake Baikal and its tributaries, influenced by seven different local pollution sources, was assessed in the areas of wastewater discharge from wastewater treatment plants (WWTPs) of the towns of Slyudyanka, Baikalsk, and Severobaikalsk, as well as domestic wastewater discharge from tourist resorts and Maksimikha settlement, runoff of hot springs from thermal baths in Zmeinaya Bay, Baikal seal rookeries, and the tourist center on Tonky Island of the Ushkanyi Islands archipelago in September 2022. The waters of the lake and the Rivers Pokhabikha, Maksimikha, and Tyya using microbiological and hydrochemical analysis methods are assessed as clean II class quality (GOST 17.1.3.07-82), except for the coastal water zone opposite the mouth of the Pokhabikha River, where the water is defined as moderately polluted. The unequal distribution of the values of the self-purification coefficient indicates a high abundance of microflora of allochthonous origin and a low activity of autochthonous microorganisms involved in self-purification processes in the studied areas of the lake. It was found that wastewater discharged by treatment facilities; water at the mouth and surface water of the Baikal in the estuary of the Pohabikha River, water in thermal baths of hot springs in Zmeinaya Bay do not meet the requirements of SanPiN 1.2.3685-21 for the maximum permissible amount of generalized coliform bacteria, Escherichia coli and Enterococcus. At all control stations in the pelagic zone of Lake Baikal, remote from the studied local polluted sites, water quality indicators did not exceed the safety water standards for surface water bodies in terms of microbiological and hydrochemical parameters.

Speciation of Sedimentary Phosphorus in an Urban Wetland: The Case of El Oulfa Pound. Casablanca, Morocco

Eutrophication remains a major concern for the quality of surface waters worldwide. This phenomenon significantly restricts water usage. The El Oulfa pond, located in Casablanca, is experiencing advanced eutrophication primarily caused by domestic wastewater discharge. Despite the cessation of these discharges and the implementation of an aeration system coupled with biological treatment, physicochemical analyses of the water body have shown an increase in phosphorus levels. This situation suggests a sedimentary origin for this nutrient, considered a limiting factor in eutrophication. This study aims to determine the various fractions of sedimentary phosphorus and their involvement in the eutrophication of the pond, using sequential chemical extraction according to Golterman. This sequential extraction revealed that the bioavailable phosphorus bound to organic matter (ASOP) represents 60.45% of the total phosphorus. Regarding mineral phosphorus, the fraction bound to calcium (CaCO3-P) is the most dominant, while the bioavailable fraction bound to iron (P-Fe) accounts for only 1.63% of the total phosphorus.

First insights into per-and polyfluoroalkyl substance contamination in edible fish species of the Indus water system of Pakistan

Per- and polyfluoroalkyl substances (PFASs) are a group of emerging contaminants, that have a wide range of applications in industrial and commercial products. The direct discharge of untreated industrial and domestic wastewater into freshwater bodies is a common practice in developing countries, which are the main contributors to PFASs in the aquatic environment. The situation is further worsened due to poor wastewater treatment facilities and weak enforcement of environmental regulations in countries like Pakistan. The current study was designed to assess PFASs contamination in muscle tissues of edible fish species from major tributaries of the Indus System, including Head Panjnad (HP), Head Trimmu (HT), Chashma Barrage (CB), Head Blloki (HB) and Head Qadirabad (HQ). The analysis of target PFAS was performed using ultrahigh-performance liquid chromatography coupled with a quadrupole Orbitrap high-resolution mass spectrometry. The highest levels of ∑17PFASs were observed in S. seenghala, C. mirigala from HB, and C. mirigala from HQ with a mean value of 45.4 ng g-1, 43.7 ng g-1, and 40.8 ng g-1, respectively. Overall, the compositional profile of fish samples was predominated by long-chain PFASs such as PFOA, PFOS, PFHpS, and PFDS. The accumulation of PFASs in fish species is dependent on the physiochemical properties of PFASs, characteristics of the aquatic environment, and fish species. Significant associations of PFASs with isotopic composition (p < 0.05), feeding habits (p < 0.05), and zones (p < 0.05) indicate that dietary proxies could be an important predictor of PFASs distribution among species. The C7–C10 PFASs exhibited bio-accumulative tendency with an accumulation factor ranging from 0.5 to 3.4. However, none of the fish samples had sufficiently high levels of PFOS to cause human health risk (HR < 1). For future studies, it is s recommended to conduct seasonal monitoring and the bioaccumulation pattern along trophic levels of both legacy and emerging PFASs.

Eco-Friendly Method for Wood Aerogel Preparation with Efficient Catalytic Reduction of 4-Nitrophenol.

The advancement of science and technology and the growth of industry have led to an escalating discharge of domestic sewage and industrial wastewater containing dyes. This surge in volume not only incurs higher costs but also exacerbates environmental burdens. However, the benefits of green and reusable catalytic reduction materials within dye processes are still uncertain. Herein, this study utilized the eco-friendly deep eutectic solvent method (DESM) and the chlorite-alkali method (CAM) to prepare a cellulose-composed wood aerogel derived from natural wood for 4-nitrophenol (4-NP) reduction. The life cycle assessment of wood aerogel preparative process showed that the wood aerogel prepared by the one-step DESM method had fewer environmental impacts. The CAM method was used innovatively to make uniform the chemical functional groups of different wood species and various wood maturities. Subsequently, palladium nanoparticles (Pd NPs) were anchored in the skeleton structure of the wood aerogel with the native chemical groups used as a reducing agent to replace external reducing agents, which reduced secondary pollution and prevented the agglomeration of nanoparticles. Results showed that the catalytic reduction efficiency of 4-NP can reach 99.8%, which shows promises for applications in wastewater treatment containing dyes. Moreover, investigation of the advantages of preparation methods of wood aerogel has important implications for helping researchers and producers choose suitable preparation strategies according to demand.

The impact of full-scale armed conflict on water bodies as water supply sources

Water resources are the basic component of sustainable development of the country. Water resources are unevenly distributed across the territory of Ukraine, most settlements and enterprises located in the northern, eastern and southern regions use surface water for water supply. The armed conflict on the territory of Ukraine directly and indirectly affects the state of water bodies, as well as the provision of basic human needs - clean drinking water. With the beginning of conflict on the territory of Ukraine in 2014, water resources regularly suffer from russian terrorist actions. The aggressor uses water resources as natural obstacles, uses the destructive effect of water to kill Ukrainians and cause maximum damage to Ukrainian economy. Also, the destruction of the water treatment and water supply system is used by russian troops as a means of pressure creating water scarcity and terrible sanitary conditions in populated areas. The impact on water resources during armed conflicts in different parts of the world have common features and significant features depending on the level of the conflict and the technology of the water supply system itself. First of all, the impact of armed conflicts on water resources is direct and indirect. The direct impact on water resources as water sources is the direct destruction of water reservoirs, water intake structures and water pipes, contamination of water bodies with the remains of sunken military equipment, mines and chemicals released into the water during the decomposition of weapons. Indirect impact on water sources is in some cases more threatening than direct. The destruction of containers with oil products, chemical substances, fertilizers, which with rainwater or directly fall into water bodies, has much greater damage than the direct impact of sunk military equipment. Forest and meadows fires and other surface cover damages lead to the reduction of the lag time to the river on the catchment area, floods increasing, flooding of larger areas, increasing amount of litter, chemical pollution, and plastics in the rivers. In most of the military conflicts described in the literature, a significant deterioration of water quality in rivers is noted, associated with the discharge of both domestic and industrial wastewater. There is the destruction of wastewater treatment plants, the inability to deliver chemicals for treatment, the inability to control unauthorized discharges of wastewater leads to the contamination of the surface water sources. The report analyses the results of surface water quality researches which officially published by the Water Resources Agency of Ukraine and other governmental and scientific organizations. Monitoring of the surface water quality is carried out on the controlled part of the Ukraine, it is not yet possible to assess the consequences of armed conflict and russian activities on the captured territories.

Assessment of heavy metal accumulation and health risk in three essential edible weeds grown on wastewater irrigated soil

The main problem facing Egypt recently is the shortage of available water resources. Therefore, farmers resort to use wastewater for irrigation. So, the present work aims to assess the impacts of wastewater irrigation on the productivity of three edible weeds (Cichorium endivia, Sonchus oleraceous and Beta vulgaris) and its effect on the nutritional value of plants and its risk on human health. This study will focus on Shibin Al Kanater region, and the physicochemical characteristics of drainage water, canal water, drainage water-irrigated soils and canal-irrigated soils were estimated. The vegetative and traits of edible weeds were determined including their photosynthetic pigments, organic and inorganic nutrients content, and heavy metals content. The health risk index (HRI) associated with consumption of polluted plants was created using the estimated exposure factor of a crop to the oral reference dosage of the toxic metal. The main results showed that biomass productivity of S. oleraceous, B. vulgaris and C. endivia increased due to drainage water irrigation with increasing percentage as 27.9, 19.6, and 19.1%, respectively. Irrigation with drainage water significantly increased the photosynthetic pigments of edible weeds. Irrigation with drainage water increased carbohydrate content, crude protein, total soluble sugar, and gross energy in all studied weeds. C. endivia, S. oleraceus and B. vulgaris plants irrigated with canal and drainage water could accumulate Fe, Zn, Cu, and Co in their roots. C. endivia, S. oleraceus and B. vulgaris plants irrigated with canal water indicated HRI more than the unit for Mn, Cu, Pb, and Cd. This research advises that regulation be put in place to prohibit irrigation using untreated drainage and to restrict the discharge of industrial, domestic, and agricultural wastewater into irrigation canals.

Study on Nutrients Concentration Trends in Tukad Badung River Toward Nutrient Recovery Potential

This study addresses the urgent concern of water quality degradation resulting from untreated domestic wastewater discharge, with a specific focus on nutrient trends within an aquatic ecosystem. The investigation centres on ammonium (NH4 +) as a significant contaminant sourced from residual foods, hygiene practices, and fertilizers, known for its association with eutrophication—characterized by excessive algae growth and oxygen depletion. The study aims to offer comprehensive insights by meticulously analysing water quality parameters across six distinct sampling points. Data collection encompassed total suspended solids (TSS), ammonia (NH4 +), nitrite (NO2 −), nitrate (NO3 −), total phosphate (PO4 −), and total nitrogen (TN). Notable variations were observed: TSS concentrations ranged from 9.00 mg/L to 20.00 mg/L, NH4 + concentrations spanned 0.00 mg/L to 1.96 mg/L, NO2- and NO3 − levels varied from 0.00 mg/L to 0.16 mg/L and 1.19 mg/L to 1.91 mg/L, respectively, PO4 3- content ranged from 0.01 mg/L to 0.65 mg/L, and TN concentrations fluctuated between 1.36 mg/L and 3.31 mg/L. These findings underscore the complexity of water quality dynamics and highlight the need for integrated management strategies to mitigate nutrient pollution’s impact on aquatic ecosystems.

Per- and polyfluoroalkyl substances in a subtropical river-mangrove estuary-bay system

Mangrove estuaries are one of the most economically valuable and biologically diverse coastal ecosystems. However, knowledge of emerging pollutants in mangrove estuaries is limited. This study provided insight into the PFAS in a river (Zhangjiang River, ZR)-mangrove estuary (Zhangjiang River Estuary, ZRE)-bay (Dongshan Bay, DSB) continuous system in Fujian Province, China. The Σ25PFAS (sum of 25 PFAS) concentrations (0.94 ∼ 62.44 ng/L) showed a declining trend from the river to bay. The Zhe-Min Coastal Current (ZMCC) can transport an abundance of PFAS, especially PFOA, from the northern sea to southern bays, which can affect the seasonal distribution of PFAS concentrations in the DSB and result in PFOA/Σ25PFAS with a decreasing trend in the DSB (28.08%), ZRE (21.15%), and ZR (14.13%), respectively. The primary PFAS sources in this area determined by the positive matrix factor model mainly contained the effluent of the wastewater treatment plant neighboring the R2 site, discharge of domestic and production wastewater, irregular emissions of aqueous film-forming foams, and fluorochemistry industry wastewater transmitted from the ZMCC. The PFAS pollution in the mangrove creek was mainly affected by the discharge of domestic and production wastewater and presented a significant point source pollution, especially during the rainy season.

Public Acceptance of Utilization of Water Reuse in Community-Based Sanitation Infrastructure (Case Study: Bandung City)

The difficulty of sustainable development is hampered by water scarcity and increased water demands, particularly in urban areas. Domestic wastewater discharges contaminate surface water bodies, such as the Citarum River. These difficulties, which disproportionately affect low-income populations, contribute to health consequences like diarrhoea and stunting. The Reinvented Toilet Project, a community-based sanitation programme, was put into place in Pasirluyu Village, Bandung, to combat water pollution. In order to lower water demand and sewage generation, it includes water reuse, reusing processed wastewater for other applications. This study assesses Pasirluyu Village infrastructure users' attitudes towards social water reuse. Surveys gathered data on demographics, views on water recycling, and information about sanitary facilities. Spearman correlation tests and descriptive analysis were carried out. The outcomes show that infrastructure users have a positive impression of water reuse. However, some people are hesitant to use reclaimed water for activities that require close personal touch. The relationship between public acceptability of water reuse for flushing toilets and acceptance for other purposes raises the possibility of a cascading expansion of water reuse practises. Keywords: community-based infrastructure, households, water reuse, water reuse aceptance

Impact of domestic and industrial effluent on marine environment at Karachi Port Trust (KPT) coastal area, Pakistan.

The extent of aquatic pollution of Karachi Port Trust (KPT) coastal area located at the south of Pakistan coast has increased considerably in the last few decades due to unrestricted discharge of sanitary waste. The current study lays emphasis on the identification of vulnerable zones severely impacted by pollution in the KPT coastal area using laboratory monitoring, geospatial techniques, and statistical analysis. During 2019, sampling was conducted along the KPT coastal area, and 54 samples of seawater were collected during pre- and post-monsoon seasons. The outcomes of physical and chemical analysis revealed that the concentrations of BOD (biochemical oxygen demand), COD (chemical oxygen demand), nitrate, phosphate, phenol, cyanide, and oil and grease frequently exceeded the permitted limit of international norms and reached much greater levels. The levels of perilous metals in the seawater samples were in the order Ni>Cr>Cu>Pb>Cd>As in both phases and also reached to elevated levels as a consequence of the indiscriminate discharge of untreated industrial and domestic wastewater. Based on detailed examination during pre- and post-monsoon, six sites near KPT, Lyari River outfall, and Karachi Harbour were identified as highly polluted zones due to heavy discharge of sanitary effluents at these sites. In particular, the industrial zones present in the formal and informal sectors of Karachi are responsible for the deterioration of the KPT coastal area. Therefore, it is advised to design and build a submerged drainage system to transport and distribute massive amounts of treated municipal and industrial waste to the deep open sea in order to minimize the high pollutant levels in these locations.

Emerging and legacy perfluoroalkyl and polyfluoroalkyl substances (PFAS) in surface water around three international airports in China

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are a large category of crucial environmental contaminants of global concerns. There are limited data on PFAS in surface water around international airports in China. The present study investigated the concentrations, distributions, and sources of emerging and legacy PFAS in surface waters around Beijing Capital International Airport (BC), Shanghai Pudong International Airport (SP), and Guangzhou Baiyun International Airport (GB) in China. Twenty-seven target compounds were quantified. The Σ27PFAS concentrations ranged from 19.0 to 62.8 ng/L (mean 36.1 ng/L) in BC, 25.6–342 ng/L (mean 76.0 ng/L) in SP, 7.35–72.7 ng/L (mean 21.6 ng/L) in GB. The dominant compound was perfluorooctanoic acid (PFOA), which accounted for an average of 27% (5%–65%) of the Σ27PFAS concentrations. The alternatives with –C6F12- group had detection frequencies ranging from 72% to 100%. The partition coefficient results indicate that the longer chain PFAS (C > 8) tend to be more distributed in the particle phase. Fifty suspect and nontarget PFAS were identified. In GB, 44 PFAS were identified, more than SP of 39 and BC of 38. An ultra short-chain (C = 2) precursor, N-methylperfluoroethanesulfonamido acetic acid (MeFEtSAA), was identified and semi-quantified. Domestic wastewater discharges might be the main sources around BC, while industrial and aviation activities might be the main sources around SP and GB.

Model parameter sensitivity and identifiability for urban river water quality: impact of domestic wastewater discharges from on-site treatment facilities

Abstract River water quality degradation is a risk to human health. Hence, many water quality models have been developed to predict the future states of water bodies and understand how the current water treatment systems will respond to future pollution loads and climatic drivers. A Japanese river was evaluated with the River Water Quality Model No.1 (RWQM1), and parameter sensitivity and identifiability analyses were executed on the model output using parameter sensitivity ranking, collinearity index, and Fisher Information Matrix-derived criterion. Among RWQM1 kinetic parameters, those related to hydrolysis, growth of aerobicheterotrophs, and first-stage nitrifiers were the most influential. Reactive soluble organic substances included in untreated gray waters, in addition to a prevalence ratio of the most advanced on-site treatment facility, strongly contributed to the model output variability. A remediation analysis revealed that a renewal to the most advanced on-site treatment facility by 20% increment was almost equivalent to the 70% decrease in the effluent concentration from an on-site treatment facility producing the highest pollutant load in terms of a BOD concentration decrease in the stream. This study provided baseline data assisting in policy implementation regarding the management of effluents from on-site treatment facilities.

A Comparative Analysis of Rural Domestic Wastewater Discharge Standards in the Yangtze River Delta Region, China

With the deepening of comprehensive improvement of rural living environments in China, various regions have issued rural domestic wastewater discharge standards based on their economic foundations, management levels, and characteristics of rural wastewater discharge. The Yangtze River Delta region, in particular, has been at the forefront of exploring these standards nationwide. By analyzing the local standards for rural domestic wastewater discharge in Shanghai, Jiangsu, Zhejiang, and Anhui provinces within the Yangtze River Delta region, along with the "Discharge standard of pollutants for municipal wastewater treatment plant" and the "Standard for irrigation water quality", it was found that the standards in each region primarily consider the classification based on the water environmental grade of the receiving water body. The pollutant concentration control requirements are generally consistent with the pollutant concentration limits for urban wastewater treatment plant discharge, but the total nitrogen and total phosphorus limits are more lenient than those for urban wastewater treatment plants. This paper can guide the transformation of rural domestic wastewater discharge from high standards to resource utilization, and provide references for the selection of wastewater treatment technologies, models, and governance strategies in the Yangtze River Delta region.

Decomposing the effect of technology on wastewater and related pollutants discharges in China

Technology assumes a pivotal role in both water conservation and pollution reduction. This study deconstructs technology into three categories: source water-saving technology (SST), process control technology (PCT), and end-of-pipe removal technology (ERT). Employing the extended IPAT and decomposition approach, it assesses the diverse impacts of these technologies on wastewater discharge in China. The findings reveal a notable decrease in industrial water consumption and wastewater discharge, yet a significant increase in the domestic sector. This increase is largely attributed to socio-economic factors. Nevertheless, the effects of SST, PCT, and ERT on wastewater discharge vary across sectors, pollutants, and regions. SST and ERT play a crucial role in diminishing industrial wastewater discharge, whereas PCT leads to an increase in approximately half of the regions. Moreover, SST and PCT tend to escalate domestic wastewater discharge in most regions, while ERT exerts a mitigating influence across the majority of regions.

Removal of microfiber and surfactants from household laundry washing effluents by powdered activated carbon: kinetics and isotherm studies.

Domestic laundry wastewater discharge contributes significantly to the presence of microfiber and surfactant pollutants in aquatic ecosystems, which have detrimental and toxic effects on humans and the environment. Investigating the efficacy of powdered activated carbon (PAC) in removing micro-/nanofibers with or without surfactant from household laundry effluent is the purpose of the current research. To simulate real-world scenarios, PAC adsorption kinetics and isotherms in laundry effluents under controlled conditions were studied. These studies showed that the kinetics obeyed a pseudo-second-order process and the isotherms varied between Langmuir and Freundlich models depending on the water types. In the results of experiments using distilled water and tap water, it was observed that the adsorption capacity was higher in tap water. When the adsorption of 0.1 μm filtered synthetic garments, detergent, and tap water was compared with the adsorption of the raw sample, it was observed that the adsorption capacity of the 0.1 μm filtered version was higher. Even though this study is preliminary, the results indicate that PAC has the capacity to serve as a viable approach for mitigating micro-/nanoplastic and surfactant contamination from laundry wastewater, thereby offering valuable guidance for advancing eco-friendly laundry techniques.