Search Results (61)

Decentralized sanitation in rural areas urgently requires accessible and nature-based solutions to achieve Sustainable Development Goal 6 (clean water and sanitation for all). However, monitoring studies of such ecotechnologies in disperse communities remain limited. This study evaluated the performance of an evapotranspiration tank (TEvap), designed with community participation, for the treatment of domestic sewage in a rural Quilombola household in the Brazilian Cerrado. The system (total area of 8.1 m², with about 1.0 m² per inhabitant) was monitored for 218 days, covering the rainy season and the plants’ establishment phase. After 51 days, the TEvap reached operational equilibrium, maintaining a zero-discharge regime, and after 218 days, 92.3% of the total system inlet volumes (i.e., 37.47 in 40.58 m³) were removed through evapotranspiration and uptake by cultivated plants (Musa spp.). Statistical analyses revealed correlations that were moderate to strong, and weak between the blackwater level and relative humidity (Pearson correlation coefficient, r = 0.75), temperature (r = −0.66), and per capita blackwater contribution (r = 0.28), highlighting the influence of climatic conditions on system efficiency. These results confirm the TEvap as a promising, low-maintenance, and climate-resilient technology for decentralized domestic sewage treatment in vulnerable rural communities, with the potential to support sanitation policy goals and promote public health. Full article

As the discharge points of domestic sewage in rural areas are scattered with large fluctuations, constructed wetlands (CWs) are of great effectiveness in treating rural domestic wastewater. In this paper, horizontal subsurface flow modular constructed wetlands (HSSF-MCWs) with different filler combinations and plant species were constructed to analyze the pollutant removal effect on rural domestic wastewater. According to the fuzzy comprehensive evaluation method, the purification effect of the systems on rural domestic wastewater was evaluated for the selection of the best system. The decentralized rural domestic sewage treatment PPP project (Phase III) in Changshu was also monitored for field application. The results indicated that the red brick–volcanic rock (RB-VR) combination showed the best comprehensive removal effect on rural domestic wastewater, with the highest average removal rate of ammonia nitrogen (NH₄⁺-N 81.0 ± 2.5%) and total nitrogen (TN 64.5 ± 3.4%). The fuzzy comprehensive index (FCI) of the RB-VR systems with four rural plants ranged from 2.60 to 3.74, in which Myriophyllum elatinoides Gaudich. showed the optimum long-term purification effect. The water quality and economic analysis results of the pilot project in Changshu indicated that the overall influent concentration was low with large fluctuations, and the qualified effluent rate was relatively low. Moreover, the equipment investment accounted for 51.24% of the overall construction investment of the project, so more economical equipment (1 m³/day and 20 m³/day) should be adopted in rural domestic wastewater treatment. Full article

An integrated hybrid system was developed, incorporating sedimentation, anaerobic digestion, biological filtration, and a two-stage hybrid subsurface flow constructed wetland, horizontal subsurface flow constructed wetland (HSSFCW) and vertical subsurface flow constructed wetland (VSSFCW), to treat rural sewage in southern Jiangsu. To optimize nitrogen and phosphorus removal, the potential of six readily accessible industrial and agricultural waste byproducts—including plastic fiber (PF), hollow brick crumbs (BC), blast furnace steel slag (BFS), a zeolite–blast furnace steel slag composite (ZBFS), zeolite (Zeo), and soil—was systematically evaluated individually as substrates in vertical subsurface flow constructed wetlands (VSSFCWs) under varying hydraulic retention times (HRTs, 0–120 h). The synergy among substrates, plants, and microbes, coupled with the effects of hydraulic retention time (HRT) on pollutant degradation performance, was clarified. Results showed BFS achieved optimal comprehensive pollutant removal efficiencies (97.1% NH₄⁺-N, 76.6% TN, 89.7% TP, 71.0% COD) at HRT = 12 h, while zeolite excelled in NH₄⁺-N/TP removal (99.5%/94.5%) and zeolite–BFS specializing in COD reduction (80.6%). System-wide microbial analysis revealed organic load (sludges from the sedimentation tank [ST] and anaerobic tanks [ATs]), substrate type, and rhizosphere effects critically shaped community structure, driving specialized pathways like sulfur autotrophic denitrification (Nitrospira) and iron-mediated phosphorus removal. Annual engineering validation demonstrated that the optimized strategy of “pretreatment unit for phosphorus control—vertical wetland for enhanced nitrogen removal” achieved stable effluent quality compliance with Grade 1-A standard for rural domestic sewage discharge after treatment facilities, without the addition of external carbon sources or exogenous microbial inoculants. This low-carbon operation and long-term stability position it as an alternative to energy-intensive activated sludge or membrane-based systems in resource-limited settings. Full article

Due to the promotion of sustainable development goals and rapid economic development, the problem of rural sewage treatment is becoming increasingly severe. In order to understand the research hotspots, progress, and trends of ecological treatment technology for rural sewage at home and abroad, this article analyzes relevant literature published between 2000 and 2023 based on the core collection databases of China National Knowledge Infrastructure (CNKI) and Web of Science (WOS) using VOSviewer and CiteSpace visualization software. The research results indicate a continuous increase in attention to ecological treatment technologies for rural sewage, both domestically and internationally. Although China started relatively late in this field, it has developed rapidly. “China Water & Wastewater” has had a significant impact in related fields domestically, and a top-tier journal has not yet been founded by China internationally. The collaboration between research authors and institutions is evident, with CNKI focusing on exploring specific governance technologies, while WOS pays more attention to the overall governance framework and critical technologies. The research hotspots of ecological treatment technology for future village and town sewage include specific treatment technologies, treatment efficiency, overall treatment strategies, and environmental impact assessments. At the same time, cross-regional and cross-border cooperation should be strengthened, interdisciplinary collaboration should be promoted, open cooperation platforms should be established, diversified publishing channels should be supported, and research on microbial communities and non-point source pollution should be deepened. Full article

The rural population shrinkage caused by China’s imbalanced regional development poses challenges to infrastructure configuration and operation. Traditional centralized sewage treatment models face issues in cost-effectiveness, facility utilization rates, and sustainable maintenance, necessitating the exploration of adaptive governance technologies under new demographic conditions. The utilization-driven governance approach is recognized as an emerging method for rural domestic sewage management. This study selects Heyang County, a representative agricultural area in Guanzhong Plain, as a case study. Through mixed-methods research integrating qualitative and quantitative approaches, we analyze the correlation between the Population Shrinkage Index (PSI) and facility operational efficiency, investigate the impact of resident population dynamics on rural sewage treatment patterns, and establish a theoretical “Source–Transmission–Sink” framework. Synthesizing local traditional governance practices with modern technological solutions, we propose a resource-oriented treatment system adapted to population shrinkage trends, comprising three technical components: source process reduction, transmission process interception, and sink process attenuation. This research emphasizes adjusting green water infrastructure (GWI) spatial configurations according to village characteristics in production–living–ecological spaces, forming a hierarchical attenuation mechanism through circular transmission pathways. This facilitates the transition from gray-infrastructure-dependent models to holistic pollution control systems with resource recovery capabilities. The findings provide theoretical foundations for policymaking and infrastructure planning in rural sewage management, offering significant references for sustainable rural water resource governance. Full article

The deterioration of the water environment in small towns in China due to urbanization has posed a significant challenge to their socioeconomic sustainability. Therefore, this study aims to employ an integrated assessment method based on the principal component analysis–minimal water quality index model (PCA–WQI_min) to objectively evaluate the water quality and analyze the pollution characteristics of Wangwenzhuang in Tianjin, thereby providing a scientific basis and decision-making support for the sustainable development of small towns. This study’s findings reveal that the PCA–WQI_min method identified four key water quality parameters essential for a comprehensive assessment of water quality across seasonal and spatial variations. The analysis revealed that the water quality in the investigated region remained at a “poor” level, with relatively consistent levels across the four catchments, ranked from poorest to best as the Xingchilong catchment area (29.61) < Jianxinpaigan catchment area (31.03) < Chilong catchment area (32.94) < Machangjian catchment area (39.61). This study revealed that the average WQI_min values slightly increased in the wet season relative to those in the dry season. This research highlights the critical importance of effectively managing domestic rural sewage and aquaculture pollution to increase surface water quality in small towns. Pollution prevention policies and multiple sources of pollution evaluation will be considered the focus of future studies. Full article

Domestic sewage pollution poses significant risks to human health and the ecological environment but sewage water is gradually recognized as a renewable water resource worldwide. To enhance water resource utilization and facilitate reclamation from domestic sewage, substantial global efforts have focused on developing systematic management strategies and advanced technologies for treatment and resource recovery. This study examines and presents the case of domestic sewage reclamation and water reuse in the rural Hangjiahu region, situated on the southern bank of Taihu Lake in Northern Zhejiang Province, Eastern China. It provides a comprehensive overview of state-of-the-art technologies implemented in the region. In rural areas, sewage treatment is decentralized and involves two primary streams: one where urine is separately disinfected and sterilized, with feces processed into agricultural fertilizer; and another where greywater undergoes bio-composting and wetland treatment to produce recycled water. Additionally, natural rainwater is collected and stored in ponds, enhancing the region’s water resources. The results demonstrate that the integration of domestic sewage reclamation and rainwater storage has effectively mitigated the risks of flooding during rainy seasons and water shortages during droughts. Remarkably, no severe floods or droughts have occurred in the region since 1991, contrasting with historical records from 1909 to 1954, when such events were frequent. This study underscores the potential for replicating these approaches in other regions facing similar challenges. Full article

Pharmaceutical and personal care products (PPCPs) have the characteristics of environmental persistence, bioaccumulation, and high toxicity, and their environmental behavior has attracted the attention in the process of sewage resource utilization in recent years. In this study, four kinds of irrigation water sources (the primary treated water of rural domestic sewage (RDS) R1, the secondary treated water of RDS R2, the ecological pond purified water R3 and river water (CK) and three kinds of water level regulations (low-, medium- and high-water level regulation of W1, W2, and W3) were set to study the migration law of 22 kinds of PPCPs in rural domestic reclaimed water (RDRW), paddy soil and rice plants. Five rice plant and soil samples were, respectively, taken from each treatment using the five-point sampling method in this study. The samples were pretreated using the solid-phase extraction (SPE) method. After pretreatment, PPCPs were quantitatively analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The objective of the research was to explore the distribution patterns in soil-crop system, further evaluating the ecological risks of PPCPs in soil and rice plants under the regulation of RDRW irrigation. The results showed that 21 kinds of PPCPs were detected in RDRW and CK, among which the concentration of ofloxacin (OFL) was the highest. Fifteen kinds of PPCPs were detected in paddy soil and rice grain, among which atenolol (ATE) content was relatively higher. Compared with CK, the total content of PPCPs in the soil surface layer (0–20 cm) was the highest under RDRW irrigation. The impacts of different water level regulations on the PPCPs content between soil profile and rice grain were not significant. In addition, the reduction rate of 15 PPCPs in soil under RDRW irrigation was greater than 85%, and the bio-concentration factor (BCF) of PPCPs in rice grain was less than 0.1. The ecological risk assessment showed that ibuprofen (IBU) was a high-risk substance pollutant, triclocarban (TRIC) was a medium-risk pollutant, ofloxacin (OFL) was a low-risk pollutant, while the other PPCPs were all risk-free pollutants under RDRW irrigation. Therefore, R3 water sources can be selected for direct agricultural irrigation, while direct irrigation of R1 and R2 water sources should be avoided. Full article

Rotating biological contactors (RBCs) are widely utilized in aerobic wastewater treatment due to their high stability, efficiency, and ease of maintenance. The choice of disc carrier material for biofilm formation is a critical factor influencing treatment performance. In the context of rural domestic wastewater treatment, the biofilm carriers must balance cost-effectiveness and high efficiency. This study focuses on the aerobic unit of a combined anoxic denitrification–deodorization filter–aerobic RBC system, specifically, the waterwheel-driven aerobic RBC, and evaluates three types of biofilm carrier media: felt, carbon felt, and nonwoven fabric. The study compares their pollutant removal performance and biofilm enrichment characteristics to identify the optimal material. The results indicate that RBCs using nonwoven fabric as the biofilm carrier exhibit superior nitrification efficiency and biocompatibility compared to the other materials, achieving average removal rates of 84.3% for COD_Cr and 80.5% for ammonia nitrogen. While the addition of nonwoven fabric slightly reduced the driving efficiency of the waterwheel-driven aerobic RBC, it significantly enhanced oxygen transfer efficiency, which explained the enhanced organic degradation and ammonia nitrification. During the biofilm stable phase, the two-stage waterwheel-driven RBC with a nonwoven fabric carrier achieved average COD_Cr and ammonia nitrogen removal rates of 86.76 ± 0.85% and 92.15 ± 1.49%, respectively. Nonwoven fabric demonstrates significant potential as a biofilm carrier for aerobic rotating biological contactors. Full article

Rural domestic sewage management is a crucial pathway for achieving Sustainable Development Goal (SDG) 6 targets. Addressing the crucial challenge of prioritizing administrative villages for rural domestic sewage treatment at the county scale requires dedicated planning. However, county-level comprehensive evaluation models designed specifically for this purpose are currently limited. To address this gap, we developed a model based on 13 evaluation indicators encompassing village distribution characteristics, villager demographics, rural economic levels, and sanitation facility conditions. To gauge the varying emphasis on these factors by different groups, a questionnaire survey was conducted among experts, enterprises, and government departments involved in the rural sewage sector in China. Two counties from distinct regions were then chosen to validate these models. The Analytic Hierarchy Process (AHP) coupled with the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) method was employed to rank the importance of the factors and determine the prioritization of rural domestic sewage management in each area. The model results indicated that priority should be given to the county government, township government, ecologically sensitive areas, and administrative villages near tourist attractions in the two selected empirical counties for governance. A sensitivity analysis showed that altitude consistently exhibited high sensitivity in influencing the ranking results across all scenarios (0.4–0.6). In addition, the empirical results obtained were largely consistent with the priorities of local governments. The proposed framework offers a practical application for decision-making systems in rural domestic sewage management at the county level, providing theoretical support and scientific strategies. This holds great significance for achieving SDG 6. Full article

Against the backdrop of promoting rural revitalization and ecological protection, the quality of rural life and living environment has been greatly improved. But with the improvement in rural living standards, the amount of domestic sewage discharge has also increased, bringing enormous pressure to the rural environment. Therefore, strengthening the construction and management of sewage treatment facilities is an important part of achieving sustainable development. This article takes rural areas in western China as an example to investigate and analyze the characteristics and existing problems of their domestic sewage treatment facilities. A set of evaluation indicators for rural domestic sewage treatment facilities suitable for western regions is constructed, which covers three aspects of evaluation indicators: Technology, Environment, and Economy. The weights of each evaluation indicator are determined through the fuzzy analytic hierarchy process. Validate the model through specific cases to ensure the practicality and accuracy of the evaluation system. This provides a certain reference for the scientific management and sustainable development of domestic sewage treatment facilities in rural areas of western China. This article has important practical significance for promoting the scientific management and sustainable development of rural domestic sewage treatment facilities in western China and also provides useful reference for rural environmental protection in other regions. Full article

Improving the rural living environment is of great significance in enhancing the life quality of rural residents and promoting rural sustainable development. The Chinese government initiated a nationwide three-year action in 2018, followed by a five-year campaign starting in 2021, to improve the rural living environment. Despite these efforts, comprehensive assessment covering multiple facets of the rural living environment at the national level remained scarce. A novel evaluation method was proposed in this study that included seven aspects and nineteen indicators, applied AHP for weighting, and PLS-SEM to analyze the relationships between variables. Then, the completion of key tasks of rural living environment improvement in 37 counties, which were incentivized by the State Council on account of its excellent governance results, was comprehensively investigated and evaluated. The assessment of key tasks in the 37 incentivized counties revealed high completion in rural household solid waste disposal, domestic sewage treatment, and toilet improvement. However, the level of the rural living environment was uneven among different regions, and the progress varied in different key tasks. The funds input had a greater impact on the comprehensive level of rural living environment than social and economic factors. Accordingly, the government should provide more targeted financial and policy support to underdeveloped areas. And priority should be given to the sewage treatment and sanitation, especially in rural and remote areas. Furthermore, local governments should diversify funding sources to ensure the sustainability of rural living environment development. These findings provide a theoretical basis for developing policies and specific plans to address the challenges of financial investment and rural living environment management in China and other developing countries and regions worldwide. Full article

Endocrine-disrupting compounds (EDCs) are emerging pollutants that can potentially accumulate in aquatic ecosystems at significant levels, with the potential to impact the health of both animals and humans. Many scientists have correlated human exposure to high concentrations of EDCs with critical physiological impacts, including infertility, thyroid imbalance, early sexual development, endometriosis, diabetes, and obesity. Several substances, such as heavy metals, belong to this family, ranging from natural to synthetic compounds, including pesticides, pharmaceuticals, and plastic-derived compounds. Domestic sewage represents a significant source of EDCs in the surrounding aquatic ecosystems. To this day, most rural and urban domestic wastewater in the municipality of Maricá is directly discharged into local aquatic environments without any treatment. The present study aimed to assess the potential contamination of the riverine and lagoonal environment in the municipality of Maricá. Water and sediment samples were collected seasonally at 18 sites along the Maricá watershed and the main lagoon, into which most of the watershed’s contributors flow. Water physico-chemical parameters (pH, reduction–oxidation potential—Eh, dissolved oxygen levels, salinity, turbidity, temperature, and fecal coliforms) were analyzed to characterize the urban influence on the aquatic environment. Sediment samples were also analyzed for grain size, total organic carbon percentage, potential bioavailable fraction of trace metals (Cd, Pb, Cu, Cr, Hg, Ni, Zn), and metalloid As. Finally, the sediment toxicity was assessed using yeast estrogen screen (YES) assays. The results obtained already demonstrate the presence of estrogenic effects and raise concerns about water quality. The current study indicates that, despite the absence of agricultural and industrial activities in the city of Maricá, EDCs are already present and have the potential to impact the local ecosystem, posing potential risks to human health. Full article

Biological trickling filtration (BTF) has the advantages of simple operation, low energy consumption, and low sludge production, and its application in the treatment of domestic wastewater in rural areas has been widely discussed. In this study, ceramic granule (R1), zeolite (R2), and sponge (R3), three typical nitrogen and phosphorus removal fillers, were selected to investigate the differences in the removal performance of COD, nitrogen, and phosphorus in BTF, analyze the characteristics of the fillers and biofilm, and determine the performance of simultaneous nitrogen and phosphorus removal. The results show that among the three fillers, zeolite has the larger specific surface area and roughness and has the best treatment effect on the adhesion performance of sewage and biofilm. The richness and diversity of the microbial community are higher, and the system is more stable, with a COD removal rate of 77.10 ± 8.67% and an NH₄⁺-N removal rate of 75.20 ± 6.64%. The TP removal rate was 22.04 ± 10.27%. The surface of ceramic particles showed a regular cluster structure with a loose distribution. The removal rate of COD was 78.49 ± 6.92%, the concentration of NH₄⁺-N in the effluent was 27.95 ± 8.23 mg/L, and the removal rate of TP was 38.83 ± 12.14%. As a polymer composite material, the sponge has large internal pores and a smooth surface, which is not conducive to biofilm adhesion. Therefore, the removal rate of nitrogen and phosphorus in sewage is poor; the removal rate of COD is 75.94 ± 6.98%, NH₄⁺-N is 27.89 ± 21.06%, and the removal rate of TP is 14.07 ± 11.76%. Compared with the metabolic function of genes, zeolites have a more stable enzyme digestion ability than the other two fillers, and the genes related to the nitrification process (amo, hao, nxr, etc.) and functional genes encoding key enzymes related to the TCA cycle are relatively abundant. Full article

To improve the removal efficiency of rural domestic sewage, a two-stage multi-soil-layer sewage treatment system with an “aeration section + non-aeration section” was designed, and its treatment performance was observed under different influent loads and aeration intensities. The experiment ran for a total of 150 days, and the results showed that the two-stage multi-soil-layer (MSL) system could effectively reduce the effluent concentration of sewage to meet discharge standards. Under the operating conditions of an influent hydraulic load of 1000 L·m⁻²·d⁻¹ and an air–water ratio of 4:1, the final effluent average concentrations of COD, NH₃-N, TN, and TP were 106.5 mg·L⁻¹, 7.4 mg·L⁻¹, 13.9 mg·L⁻¹, 0.12 mg·L⁻¹, and 18.6 mg·L⁻¹, respectively, with average removal rates of 85.3%, 82%, 72.5%, 96%, and 85%. A longer hydraulic retention time and ideal anoxic conditions were ensured by designing a certain effluent height in the system. Adding aeration to the system allowed for a synchronous nitrification–denitrification reaction under reasonable influent loads, ultimately enabling the effluent to meet discharge standards. Full article