Search Results (69)

The multi-media environmental behavior of dissolved organic matter (DOM) is closely related to biogeochemistry and water quality. In this study, we characterized the multi-media distribution patterns and sources of DOM in a human-intensive watershed based on fluorescence measurements and fluorescence quotient (FQ) methods. Clay showed higher proportions in urban areas compared with rural areas. The biological index decreased with the increased similarity of DOM between sediment and a wastewater treatment plant (WWTP)/domestic sewage. The similarity of DOM between sediment and aquaculture was negatively related to coarse silt (Pearson, p < 0.05). In the water, C2 was more abundant in urban areas than in rural areas; among all sources, the WWTP exhibited the highest similarity (98.04%) of DOM with water, which was higher than that between sediment and the WWTP. The fluorescence index decreased with the increased similarity of DOM between waters and the WWTP/domestic sewage. The FQs for some amino acid-like materials and microbial byproducts between sediment and water were negative, while those for humic-like and fulvic-like materials between sediment and water were positive. Structure equation model (SEM) results showed that sediment grain size exerted positive effects on the distribution of C1 between sediment and water and negative effects on the distribution of C3 between sediment and water. The results demonstrated that the distribution of DOM between sediment and water, as well as the source contribution to DOM in sediment, was related to the sediment grain size, revealing the impact of sediment on the multi-media environmental behavior of DOM. Full article

Groundwater quality remains insufficiently characterized in the rural agriculture–residential interface of the Huaibei Plain, particularly with respect to nitrate (NO₃⁻) occurrence, hydrochemical controls, source contributions, and population-specific health risks. In this study, multivariate statistical analysis, source apportionment models, and health risk assessment models were applied to investigate the hydrochemical characteristics of groundwater and related non-carcinogenic risks to different populations. NO₃⁻ content exceeded the World Health Organization (WHO) guidelines for drinking water in 60.0% and 62.5% of wet- and dry-season groundwater, respectively. Groundwater NO₃⁻ was mainly influenced by agricultural non-point inputs and domestic sewage, whereas major-ion composition was primarily governed by water–rock interactions. Our deterministic health risk assessment model reveals that the hazard index (HI) exceeded the acceptable threshold of 1.0 in 76.25%, 65.00%, 66.25%, and 56.25% of groundwater samples for infants, children, adult females, and adult males, respectively. These results indicate that continuous monitoring, improved sewage collection, and more controlled nitrogen management are required in the rural agricultural–residential interface of the Huaibei Plain with regard to shallow domestic groundwater. Full article

This study integrates geostatistical analysis, correlation analysis and pollution load assessment to investigate the spatial distribution characteristics and environmental impacts of rural domestic pollution emissions in the Yellow River Basin, laying a foundation for the sustainable development of rural areas and zoned and classified management of rural domestic sewage in the basin. Results show that: ① The average rural domestic sewage discharge coefficient in the basin is 25.67 L/(person·day), and the average pollutant generation coefficients are as follows: chemical oxygen demand (COD) 23.08 g/(person·day), ammonia nitrogen (NH₃-N) 0.71 g/(person·day), total nitrogen (TN) 1.29 g/(person·day) and total phosphorus (TP) 0.11 g/(person·day); ② Rural sewage discharge coefficients near urban areas are higher than other rural areas in the same jurisdiction, with downstream areas significantly exceeding upstream non-urban areas; ③ Youth population, illiterate population, average education years and annual precipitation are key influencing factors, showing significant negative correlations with the former two and positive correlations with the latter two; ④ The maximum equivalent load contribution of rural domestic pollution to the water quality objectives of the Yellow River’s main streams and tributaries is merely 2.01%. Overall, rural per capita domestic sewage discharge in the basin is at a low level with obvious regional differences, mainly correlated with demographic, educational and climatic factors, and its impact on the basin’s water quality objectives is negligible. Full article

Owing to topographical constraints, rural domestic sewage management in karst areas faces unique challenges (scattered pollution sources, fragile hydrogeology, and inadequate infrastructure), but research on decentralized treatment technologies and their microbial mechanisms in this area remains scarce. This study aimed to evaluate the efficiency of a physicobiological process (pre-treatment + BAF) for decentralized rural sewage treatment in karst areas and clarify the relationship between microbial community composition and treatment efficiency under different scales. Annual analyses of influent/effluent pollutants and 16S rRNA gene sequencing were conducted for BAF systems of varying scales. The average removal rates of COD, TN, NH₃-N, and TP were 65.35–79.25%, 32.09–66.66%, 49.50–75.42%, and 44.92–67.69%, respectively. Treatment efficiency varied significantly with scale, being higher in larger systems (p < 0.001). All scales shared a core microbial community (dominated by Proteobacteria, Bacteroidetes, and Chlorobi), but the relative abundance of core taxa decreased with decreasing scale. Nitrification and denitrification were positively associated with NH₃-N and TN removal, respectively. Smaller treatment units were more prone to miscellaneous bacteria proliferation, potentially reducing treatment stability. This study fills the research gap of decentralized BAF application in rural karst areas and provides a scientific basis for the scale optimization of rural wastewater treatment facilities. Full article

Improving the living environment in rural areas is an important task and a key breakthrough point in implementing the rural revitalization strategy. It not only directly affects the vital interests and health protection of farmers, but is also an important measure to promote ecological civilization construction and achieve the development goal of a beautiful China. Taking environmental demonstration villages in Shaanxi Province as the research object, questionnaire data were obtained through field research and face-to-face interviews. This study constructs an evaluation index system covering five dimensions: village appearance, domestic sewage treatment, rural toilet renovation, domestic waste treatment, and construction and management mechanism. The entropy method is used to determine indicator weights, and fuzzy comprehensive evaluation is applied to measure the implementation effect. The research results indicate that the overall effect is between “average” and “good” (score 3.924), with domestic sewage treatment scoring highest and construction and management mechanism lowest. The study identifies key problems such as low farmer participation, insufficient funding sources, inadequate infrastructure maintenance, and weak environmental awareness. Based on these findings, countermeasures are proposed: enhancing farmers’ environmental awareness and participation; diversifying capital investment; improving infrastructure and establishing long-term management mechanisms; cultivating social capital; and strengthening the leading role of the government. This study provides empirical evidence and policy recommendations for improving rural environmental governance. Full article

The precise identification of pollution sources constitutes a cornerstone for effective water environment management in mountainous watersheds. This study employed principal component analysis–absolute principal component scores–multiple linear regression (PCA-APCS-MLR) receptor modeling to analyze monthly water quality indicators across the Longxi River Basin. Results revealed comparable water quality between the main stream and its tributaries, with no statistically significant differences identified. Water quality exhibited a distinct spatial pattern, with superior conditions in the upstream and downstream segments compared to the middle reaches. Water quality parameters exhibited significant seasonal variations. During the wet period, the degradation of water quality was primarily driven by diffuse agricultural sources, contributing 42.9%, followed by watershed background levels and surface runoff. In the dry season, rural domestic wastewater (39.3%) was the leading pollution source. For Permanganate index (COD_Mn) exceedance, basin background and agricultural non-point sources in the wet season were the main contributors (46.8% and 44.7%, respectively). For ammonium nitrogen (NH₃-N), wet season agricultural non-point sources (44.4%) and dry season rural domestic pollution (71.8%) were key contributors. Agricultural non-point sources were the dominant pollution source for total nitrogen (TN) in the wet season (84.2%). Effective water quality improvement in the Longxi River Basin hinges on targeted strategies—to mitigate diffuse agricultural sources through optimized fertilization, and to enhance the collection and treatment of rural domestic sewage. This study not only enhances the understanding of pollution source distribution and quantification in mountainous watersheds, but also serves as a vital reference for formulating targeted water environment management strategies. Full article

This study systematically evaluated the removal performance of iron–carbon (Fe/C) micro-electrolysis materials with different proportions and preparation methods for nitrogen (N), phosphorus (P) and chemical oxygen demand (COD) in domestic sewage. This study investigated the effects of different Fe/C ratios, hydraulic retention time (HRT), raw materials and sintering bonding conditions on the efficiency of domestic sewage treatment through both static and dynamic experiments. In the static experiments, iron filings (IFs), steel slag (SS), and coconut shell carbon (CSC) were physically mixed, whereas the dynamic tests simulated the continuous treatment of domestic sewage. The results indicated that the Fe/C materials effectively removed P, particularly materials with high Fe/C ratios, which achieved removal rates of 96–98%. The COD removal efficiency of low Fe/C ratio material was better, reaching a removal rate of more than 70% under the optimal conditions. For Fe/C physical mixed materials, SS replacing IFs had excellent performance in ammonia nitrogen (NH₄⁺-N) removal (>93%), but other indicators were poor, which limited its application. Results from the continuous flow experiment indicated that the physically mixed filler with an Fe/C mass ratio of 2:1 showed excellent and stable TP and COD removal rates (98.6% and 92.8%) for the actual domestic sewage. In addition, the Fe/C micro-electrolysis filler sintered at 400 °C using kaolin as a binder exhibited good potential for pollutant removal, providing a feasible solution for reducing energy consumption. This study provides important data support for the development of low-cost and efficient decentralized rural sewage treatment technology. Full article

The unsuitable performance of or deficit in basic sanitation infrastructure, especially in sparsely populated rural communities, remains critical, particularly in many developing regions, and demands sustainable, cost-effective, and easily operated solutions. Thus, the objective of this Review is to analyze design parameters for evapotranspiration tanks (EvapTs), adopted as nature-based solutions for zero-discharge domestic sewage treatment. The literature search was conducted using the Scopus and Web of Science databases, complemented by backward citation tracking. From 4434 records, 29 studies were selected based on specific criteria, such as the availability of design data and their application in urban or rural contexts. The main findings indicated required areas per inhabitant ranging from 0.5 to 7.7 m², primarily influenced by climate conditions and the type of plant used. Statistical analysis showed a negative correlation between the area of the evaporation tanks and the mean annual temperature, with a Pearson correlation coefficient (r of −0.74). For mean annual temperatures between 19 and 27 degrees Celsius, linear regression showed a variation between 4.7 and 0.6 m²/inhabitant with a reduction coefficient of −0.51 per degree Celsius, suggesting that warmer climates require smaller system areas per capita. Most studies were conducted at full scale, with Brazil accounting for the highest number of publications. EvapT is identified as a promising ecological technology that is particularly suitable for rural settings. However, it still requires technical standardization, cost–benefit analysis, and research on social acceptance. The adoption of clear design criteria may enhance system replicability, support public policy development, and contribute to SDG 6—Clean Water and Sanitation for All. Full article

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