Pollutant Load Reductions Research Articles

Effects of low impact development on runoff pollution and water quality resilience in an urbanized estuary area

In urbanized estuary areas, water quality often deteriorates due to the impact of surface runoff or overflow during heavy rainfall events. Low impact development (LID) can mitigate this impact and improve water quality resilience. However, there were few studies on quantifying this effect of LID, particularly in estuary areas. In this study, water quality resilience is expressed as the abnormal rate of water quality during rainfall events and the time required for water quality to recover from abnormality to normal. In this study, a coupled Storm Water Management Model (SWMM) and Environmental Fluid Dynamic Code (EFDC) model is used to examine the effects of LID on runoff pollution and water quality resilience in the Shenzhen River estuary (including Shenzhen River and Deep Bay) in China. The results indicate that (1) The inflow volume into the estuary is not only affected by the drainage area but also by the service area and capacity of the sewer interception system; LID can reduce not only the stormwater runoff but also the overflow from the interception systems along rivers. (2) The marginal benefit of the LID proportion increase in pollution load reduction diminishes as the proportion of LID implementation increases. (3) LID can reduce the high value of pollution concentration caused by rainfall runoff; and the reduction effect on the rivers is greater than that on the bay. (4) The rivers and the estuary have a much higher abnormal rate than the inner bay and the outer bay; however, the estuary and the inner bay have longer recovery time than the rivers and the outer bay. The maximum abnormal rate, average abnormal rate, and recovery time of different indicators in the entire estuary area are decreased by 10%-189%, 6%-71%, and 0.8–1.1 cycles when the runoff from 80% of built-up area is treated by LID facilities; LID can significantly reduce abnormal rate of the rivers and recovery time of the inner bay. Therefore, the proposed metric and model can fully reflect the spatial variations in water quality resilience, and LID can enhance the water quality resilience of the urbanized estuary areas under rainfall.

Modeling the effect of land-use change on runoff water quality in the urban watershed: a case study of Settat city, Morocco

ABSTRACT The purpose of this study is to create a model of the quantity and quality of runoff from the urban watershed. The modeling was performed using a personal computer stormwater management model (PCSWMM) tool and was based on washoff and buildup for total suspended solids (TSS), total nitrogen (TN), and total phosphorus (TP) measured in the field. In addition, low impact development (LID) was used under four different scenarios to improve runoff control of the urban hydrologic cycle and reduce pollutant concentrations. Model performance was analyzed using the R2 and NSE goodness-of-fit indices. Thus, three typical rainfall events, as well as field measurement parameters (TSS, TN, and TP), were used for the model's calibration and validation. The base scenario quantified the runoff volume and pollutant load without any intervention in the runoff process control. Scenarios S2 (BR: bioretention) and S3 (PP: permeable pavement) contributed, separately, in reducing runoff and pollutant load but with relatively small percentages. In addition, the results show that scenario S4 (BR and PP) has the most significant impact on flow reduction, by about 10% compared with the base scenario, as well as on the pollutant load reduction, by about 31, 29, and 40% for the parameters TSS, TN, and TP, respectively.

Comparative assessment of pollution control measures for urban water bodies in urban small catchment by SWMM

Under the current increasingly serious water pollution situation in urban, the comprehensive treatment and protecting measures in urban small catchment are the necessary step to the water pollution treatment, not only focus on the water bodies themself. In this paper, the Luojiagang river channel and its catchment in Wuhan, which has been heavily impacted by water pollution, are taken as an example for the comparative assessment of pollution control measures in order to explore the effective and sustainable schemes including the LID (Low Impact Development---LID) by using SWMM model (Storm Water Management Model---SWMM). Through the comparison of pollution treatment measures based on scenarios simulation with the baseline scenarios, it was found that the reduction effects of pollutant peak concentrations at the outlet node of Luojiagang River had the decreasing order of: the combined measures (COS) > LID control > the water diversion from Donghu Lake (WAD) > the sewage treatment (SET) > the sediment dredging (SED), and the reduction effects of total pollutant load had the decreasing order of: LID > COS > SET > SED > WAD. The results show that the control of non-point source pollution is the key for the improvement of water quality in Luojiagang River, and LID plays important role in the reduction of both pollutant peak concentrations and load. This study has the implication for the decision making of the water pollution controlling schemes in urban small catchment.

Enhanced textile wastewater remediation in Phragmites karka-based vertical flow constructed wetlands using Phragmites-derived biochar

Vertical flow-constructed wetlands (VFCWs) are treatment systems that can be used for the phytoremediation of highly polluted textile wastewater. Using plant-derived biochar to simultaneously improve the contaminant removal performance of CWs and sustainable utilization of harvested plant biomass is an interesting proposition. The present study explored the phytoremediation potential of Phragmites karka and verified the impact of using P. karka-derived biochar as a substrate in VFCWs for the treatment of textile wastewater. For this, three types of VFCWs were designed; (i) non-vegetated (VFCW), (ii) vegetated with P. karka (VFCW–P), and (iii) vegetated with P. karka and amended with P. karka-derived biochar (VFCW-BP) and semi-batch experiments were conducted. The investigation confirmed that wetlands using biochar as substrate were more efficient than other wetlands in pollutant load reduction. The maximum pollutant removal efficiencies were recorded for VFCW-BP vis-à-vis COD (83.61%), color (77.87%), chloride (73.22%), calcium (73.52%), sodium (67.18%), and potassium (75.72%) after five days. Furthermore, biochar addition enhanced the growth conditions for wetland plants by alleviating osmotic and oxidative stresses and hence helped them to perform better while removing pollutants. The maximum reduction of various pollutant parameters was reached within 72 h, after which remediation efficiency was slowed down. The study suggests that VFCW with biochar amendment is a useful strategy for textile wastewater treatment. Because the experimental design satisfies the needs for low-cost wastewater treatment, it may find widespread applications.

Pollutant Load Capacity of Rawa Besar Lake, Depok, West Java

Depok City has dozens of lakes and one of them is Lake Rawa Besar. The Depok government gives priority to Rawa Besar Lake to be development as a tourist destination. At this time the waters of Rawa Besar Lake are in a polluted condition caused by domestic waste, land use change, chicken farming and floating net caramba. The study aims to analyze water quality, determine the carrying capacity of pollutant loads and provide recommendations for pollutant load reduction. The calculation of the Pollution Load Capacity refers to Minister of Environment Regulation No. 28 of 2009. Based on water quality analysis, 5 parameters exceed the quality standard, such as BOD, COD, total phosphate, total nitrogen, and total coliform. Using the model and calculation of the pollutant load capacity of lake and/or reservoir. The pollutant load capacity of Lake Rawa Besar for BOD parameters is 50.26 kg/year while the existing load is 262.76 kg/year, COD is 418.81 kg/year existing load is 1150.41 kg/year, phosphate is 0.50 kg/year existing load 26.45 kg/year, nitrogen 12.56 kg/year existing load 85.88 kg/year and total coliform 8.4 x 104 amount/year existing load 9.6x106 amount/year. The burden of incoming pollutants exceeds the pollutant load capacity of Lake Rawa Besar. Pollution control efforts are carried out by implementing communal wastewater treatment systems such as an Anaerobic Baffled Reactor (ABR).

Occurrence and environmental fate of anti-influenza drugs in a subcatchment of the Yodo River Basin, Japan

Understanding the current situation and risk of environmental contamination by anti-influenza drugs in aquatic environments is key to prevent the unexpected emergence and spread of drug-resistant viruses. However, few reports have been focused on newer drugs that have recently been introduced in clinical settings. In this study, the behaviour of the prodrug baloxavir marboxil (BALM)—the active ingredient of Xofluza, an increasingly popular anti-influenza drug—and its pharmacologically active metabolite baloxavir (BAL) in the aquatic environment was evaluated. Additionally, their presence in urban rivers and a wastewater treatment plant (WWTP) in the Yodo River basin was investigated and compared with those of the major anti-influenza drugs used to date (favipiravir (FAV), peramivir (PER), laninamivir (LAN), and its active metabolite, laninamivir octanoate (LANO), oseltamivir (OSE), and its active metabolite, oseltamivir carboxylate (OSEC), and zanamivir (ZAN)) to comprehensively assess their environmental fate in the aquatic environment. The results clearly showed that BALM, FAV, and BAL were rapidly degraded through photolysis (2-h, 0.6-h, and 0.4-h half-lives, respectively), followed by LAN, which was gradually biodegraded (7-h half-life). In addition, BALM and BAL decreased by up to 47 % after 4 days and 34 % after 2 days of biodegradation in river water. However, the remaining conventional drugs, except for LANO (<1 % after 10 days), were persistent, being transported from the upstream to downstream sites. The LogKd values for the rates of sorption of BALM (0.5–1.6) and BAL (1.8–3.1) on river sediment were higher than those of conventional drugs (−0.5 to 1.7). Notably, all anti-influenza drugs were effectively removed by ozonation (>90–99.9 % removal) after biological treatment at a WWTP. Thus, these findings suggest the importance of introducing ozonation to reduce pollution loads in rivers and the environmental risks associated with drug-resistant viruses in aquatic environments, thereby promoting safe river environments.

Runoff Control Performance of Three Typical Low-Impact Development Facilities: A Case Study of a Community in Beijing

The development of sponge cities advocates for sustainable urban rainwater management, effectively alleviating urban flood disasters, reducing non-point-source pollution, and promoting the recycling of rainwater resources. Low-Impact Development (LID) serves as a key strategy in this context, providing essential support for urban rainwater control and pollution reduction. To investigate the runoff control effects of LID measures and to reveal the relationship between facility runoff control performance and installation scale, this study focuses on a sponge community in Beijing. A SWMM model was constructed to analyze the rainwater flood control and pollutant load reduction effects of different LID facilities, including bio-retention cells, green roofs, and permeable pavements. Using evaluation indicators such as surface runoff, node overflow, and pollutant control rates, this study examined how facility performance varies with installation scale under different rainfall conditions. The combination scheme of LID equipment optimal configuration is designed by using multiple criteria decision analysis (MCDA) and cost–benefit theory. The results indicate significant differences in performance among the various LID facilities across different rainfall scenarios. Specifically, the optimal installation proportion for runoff and overflow control of permeable pavements were found to be between 30% and 70%. Green roofs demonstrate superior performance in handling extreme rainfall events, while bio-retention cells exhibit significant effectiveness in controlling Total Suspended Solids (TSSs). Through comprehensive performance evaluation, this study identified the optimal combination scale under a 3-year rainfall recurrence interval as 30% permeable pavements, 20% green roof, and 60% bio-retention cells. This combination effectively leverages the strengths of each facility, ensuring system stability and efficiency while also demonstrating optimal management efficiency in cost–benefit analyses. The findings of this research provide valuable insights for future urban water management and infrastructure development.

Agricultural watershed conservation and optimization using a participatory hydrological approach.

Maximizing the impact of agricultural wastewater conservation practices (CP) to achieve total maximum daily load (TMDL) scenarios in agricultural watersheds is a challenge for the practitioners. The complex modeling requirements of sophisticated hydrologic models make their use and interpretation difficult, preventing the inclusion of local watershed stakeholders' knowledge in the development of optimal TMDL scenarios. The present study develops a seamless modeling approach to transform the complex modeling outcomes of Hydrologic Simulation Program Fortran (HSPF) into a simplified participatory framework for developing optimized management scenarios. The study evaluates seven conservation practices in the Pomme de Terre watershed in Minnesota, USA, focusing on sediment and phosphorus pollutant load reductions incorporating farmers' opinions to guide practitioners toward implementing cost-effective CPs. Results show reduced tillage and filter strips are the most cost-effective practices for non-point source pollution reduction, followed by conservation cover perennials. The integration of SAM with HSPF is crucial for sustainable field-scale implementation of conservation practices through enhanced involvement of amateur-modeling stakeholders and farmers directly connected to fields.

Can the best management practices resist the combined effects of climate and land-use changes on non-point source pollution control?

Climate and land-use changes have an overlying impact on non-point source (NPS) pollution in river basins. However, the control effect of Best Management Practices (BMPs) for NPS pollution is not yet clear under future scenarios. The Soil and Water Assessment Tool (SWAT) model was coupled with the entropy-weighted method, global climate patterns and land-use data to explore the dynamic variations in total nitrogen (TN) and total phosphorus (TP) loads in the Jing River Basin during the baseline (2000−2020) and future periods (2021–2065), evaluate the pollution reduction effectiveness of individual and combined BMPs, and propose practical BMP configurations. Results indicate that a future trend of urban land expansion, particularly in the economic scenario (LU_SSP585), leads to weakened environmental ecosystems, while the sustainable scenario (LU_SSP126) exhibits more balanced land development. The MIROC-ES2L model demonstrates higher Taylor skill scores, forecasted significant increases in precipitation, maximum, and minimum temperatures under the SSP585 scenario. Spatial heterogeneity in TN and TP loads is notable, showing an upward trajectory in the future. The interaction between land-use and climate change has complex effects on TN and TP loads, with land-use-induced TN changes being relatively small (4.6 %) and TP changes substantial (24.3 %). The spatial distribution, under overlying effects, leans towards the influence of climate change, emphasizing its dominant role in TN and TP load variations. Distinct differences exist in the reduction of NPS pollution loads among different BMPs, with combined BMPs demonstrating superior effectiveness. The environmental-cost effectiveness trends of BMPs remain consistent across various future scenarios. RG (Return agricultural land to grass), RG + TT (Terracing), and RG + FR10 (Fertilizer reduction: 10 %) + GW (Grassed waterway) + FS (Filter strip) + TT emerge as the most effective single, double, and multiple BMP combinations, respectively. The results offer valuable insights for preventing and mitigating future NPS pollution risks, optimizing land-use layouts, and enhancing watershed management decisions.

Production of microalgae in wastewater and brackish waters: kinetic, lipid content, bioremediation and cost analysis studies

ABSTRACT The cultivation of microalgae in domestic wastewater offers a sustainable solution for the treatment of effluents, while at the same time producing biomass rich in lipids, potentially usable in the production of biofuels. Furthermore, reuse contributes to the treatment of wastewater, transforming a byproduct into a valuable source of nutrients for the production of microalgae biomass. This study involves the production of microalgae in open cultivation, using domestic effluents as a source of nutrients in brackish environments, to study the potential for biodiesel production. Intracellular lipids were between 17 and 20%. As for the bioremediation capacity, the results showed removal levels greater than 95% of nutrients, as well as bacterial and pollutant load reduction. The growth kinetics and the prediction of theoretical kinetic models through the use of computational tools show significant differences, due to the lack of control of process parameters in open cultivations. Based on the literature review and market research, a cost analysis for large-scale production in open crops was made, comparing with closed crops and finding lower costs in the implementation, maintenance and production of biodiesel in the production open.

Analyzing Priority Management for Water Quality Improvement Strategies with Regional Characteristics

As the management areas for NPS pollution continue to increase, it is essential to conduct a situation analysis considering the regional characteristics and the scope of pollution reduction. In this study, the focus is on differentiating regional (urban, agricultural) characteristics to enhance water quality and reduce pollution loads in the increasing management areas for NPSs. Furthermore, priority management areas are identified based on urgency and vulnerability, and management strategies are proposed. The assessment involved evaluating both streamflow and water quality (T-P) using long-term monitoring data and watershed models (SWAT and HSPF) that take into account regional characteristics. The results indicated notable regional improvements, with T-P pollution reductions ranging from 20.7% to 26.8% and T-P concentration reductions ranging from 16.4% to 24.7% compared to baseline conditions in unmanaged areas. Based on these research findings, it is anticipated that the efficient and effective management of NPS pollution can be implemented on a regional basis. Moreover, the results of this study will not only contribute to the establishment of pollution standards, but also significantly impact the evaluation and proposal of management objectives, thereby making a substantial contribution to national water quality policies.

Comparative studies on enzymatic efficacy and microbiological properties of Garbage Enzyme produced from various fruits and vegetables peels in biodegradation of cow dung

The present work was conducted to study the enzymatic potentials and microbiological properties of Garbage Enzyme produced from various fruits and vegetables peels. Completely randomized designed experiment was framed with seven treatments each with fruits and vegetable peels separately. All the treatments exhibited positive result for Amylase Test, Lipase Test, Cellulase Test, Urease Test, Protease Test, MR Test and Alcohol and low pH, indicating that Garbage enzyme produced from fruit and vegetable wastes contained mixture of enzymes, alcohol and acid brought about by microbial fermentation. Highest enzymatic efficacy was shown by T3- Pomegranate followed by T6- Banana. GE produced by vegetable wastes was less effective than fruit peels and maximum enzymatic activity exhibited by T1-Radish. A total of 27 amylase producing bacteria, 27 protease producing bacteria, 26 lipase producing bacteria, 26 cellulase producing bacteria 24 urease producing bacteria, 21 pectinase producing bacteria and 01 Amylase producing fungus was screened isolated from all the treatments. Garbage enzyme treatments in tray assay neutralized the alkaline pH of cow dung as garbage enzyme is acidic in nature. Highest Nitrogen (172 Kg/Hec) content was found when treated with garbage enzyme produced with banana peel. It is concluded that Garbage enzyme contains various enzymes, acid, and alcohol, can be utilized as a low cost alternative to biodegrade wastes to reduce pollution load of our environment. Keywords: Garbage Enzyme, vegetable and fruit wastes, enzyme activity, biodegradation

Pollution Load Reduction from Domestic Wastewater with Electrocoagulation Process for Agricultural Reuse

Objectives: The present study is aimed to investigate electrocoagulation of domestic wastewater and assessment of pollutants removal efficiency for potential reuse in agriculture. Methods: The electrocoagulation treatment of domestic wastewater with Fe – Fe electrodes was performed under optimal conditions of pH (8.0), current density (0.6 mA/cm2), treatment time (45 minutes), and NaCl dose (2.8 g/L) in a slurry type of reactor. The primary clarified and biotreated domestic wastewaters were subjected to electrocoagulation with Direct Current (DC) as power source. Findings: There was observed higher pollutants removal efficiency from the biotreated wastewater as compared with the primary clarified wastewater after electrocoagulation. The treated wastewaters showed significant removal of pollutants in terms of BOD (79.5% – 87.9%), COD (86.8% – 89.5%), TDS (87.4% – 89.9%), TSS (66.7% – 75.3%), conductivity (77.8% – 78.4%), turbidity (74% – 81.2%), colour (77.7% – 86.2%), nitrates (44.1% – 51.7%), and phosphates (48.7% – 55.9%) after electrocoagulation treatment. Electrocoagulation considerably improved the biodegradability index of the primary clarified (0.59 to 0.92) and biotreated (0.69 to 0.8) wastewaters. This indicates easy removal of the pollutants further by biological processes in the aquatic ecosystems. Electrocoagulation demonstrated potential for removal of pollution from the domestic wastewater for productive reuse in agriculture and urban areas. Novelty: There exist few studies of use of electrochemical process for treatment and reuse of domestic wastewater. The treated waters complied with the regulatory standards and had satisfactory quality for reuse in agriculture and urban activities. Keywords: Electrocoagulation, Domestic wastewater, Biodegradability index, Agricultural reuse, National Green Tribunal

Pollutant load estimation and load reduction target (LRT) projection for total maximum daily load (TMD) allocation on tropical rivers

Pollutant load may be defined as the mass of a substance that passes a particular point of a river in a specified amount of time. Meanwhile, estimation of pollutant loading and identification of their sources is crucial to environmental management and planning. For the first time (in this study), Flow rate measurement was used to estimate daily pollutant loading from Intermittent water quality concentration data, using a 2-dymensional Water Quality Analyser (WQA). Subsequently, Total Maximum Daily Load (TMDL) was determined using the Load duration approach, while Load Reduction Targets were projected for the future, the using regression option of trend analysis available in the WQA. Out of the ten parameters used for the study, BOD, NH3, and TSS have been identified as the most critical pollutants in the area, which require average load reduction of 3898.88 kg-day, 1053.28 kg-day, and 444,716.50 kg-day respectively, to achieve water quality class II, until 2030. Moreover, the study reveals that the load reduction target for BOD and TSS would decrease in the future, while that of NH3 increases (p < 0.001). This is even as significant variability also exists for the projected load reduction target over the months throughout the projected period (p < 0.01). It was concluded that WQA provides a cost and time effective, and a reliable means for estimation of Pollutant load and projection of Load Reduction Target. The study recommends source identification for the critical pollutants into the river and allocation of TMDLs using the dynamic flow approach.

Pollution Load Coordination and Eco-Compensation for Trans-Boundary Water Pollution Control: The Case of the Tri-Border Region of the Yangtze Delta

A partitioned governance mode, in the absence of multilateral cooperation, always culminates in recurring instances of trans-boundary conflicts and critical degradation of water bodies in border regions. Addressing the existing gaps in quantitative trans-boundary pollution control research in extensive river network, a new approach was designed to strategically guide water pollution control initiatives throughout the entire tri-border region of the Yangtze Delta (TBYD) via the following steps: (1) Building upon an analysis of the trans-boundary river hydrodynamics, the tri-border effective coordination scope (TECS), i.e., a strategic coordination scope for coordinated pollution control, was delineated, and 13 county-level administrative districts were identified as effective contributing regions for detailed coordination. (2) Considering water quality standard (WQS) attainment in the trans-boundary cross-sections, a one-dimensional mathematical model covering the complex river network was established. Then, the load capacities for all the contributing administrative regions were determined to facilitate coordinated pollution load reduction across the TECS. (3) Leveraging from the sewage treatment costs within the TECS, a standardized eco-compensation criterion was established to guide the coordinated compensation practices across the TECS. (4) By comparing the practical pollution discharging amount, the coordinated load reduction rates and eco-compensation payments of all 13 contributing administrative districts for trans-boundary pollution control were assessed. These assessments will guide policy promulgation and provide quantitative data support for harmonizing pollution control policymaking and addressing intricate trans-boundary pollution issues in complex river networks.

Advancing equitable stormwater management: A decision support tool integrating best practices for nutrient removal and environmental justice

Stormwater runoff is a significant contributor to nutrient pollution, leading to water quality degradation and ecological imbalances. The management of stormwater runoff and nutrient pollution faces significant challenges due to inadequate assessment tools for evaluating nutrient loads across multiple watersheds at the state level and the absence of an open-source tool that can comprehensively assess the effectiveness of stormwater Best Management Practices (BMPs) in nutrient removal while incorporating environmental justice (EJ) considerations. To address these challenges, we developed an innovative online statewide tool that identifies areas where BMP planning needs to be prioritized to address environmental disparities resulting from high pollutant loads intersecting with disadvantaged communities, alongside tracking pollutant loads after various BMP implementations. In doing so, we estimated pollutant loads including total phosphorus (TP), total nitrogen (TN), biochemical oxygen demand (BOD), and total suspended solids (TSS) from urban land use in 1378 HUC-12 watersheds across Florida using EPA's pollutant load estimate tools (PLET), which calculates loads based on factors such as land use, septic systems and wastewater discharge, soil characteristics, and precipitation. To integrate BMP implementation with EJ considerations, a social vulnerability index was developed to identify tiers of sociodemographic disparities using racial/ethnicity metrics (e.g., % black, % Hispanic, etc.) and socioeconomic metrics (e.g., median household income, educational attainment, etc.). We then investigated the effectiveness of 28 urban stormwater BMPs in reducing pollutant loads and estimated post-BMP loads for each watershed. Hotspots of nutrient pollution were primarily identified in coastal areas, with residential land use as the main contributor. Miami-Dade, Broward, and Hillsborough counties had the highest sociodemographic disparities. In addition, central and southern Florida exhibited a disproportionate exposure of disadvantaged communities to pollutant loads. The developed online tool contributes significantly to holistic watershed management by features including visualizing the distribution of nutrient pollution loads across state watersheds, identifying areas with high pollutant loads intersecting with disadvantaged communities, and quantifying pollution load reductions post-BMP implementation. This research promotes equitable outcomes and empowers stakeholders in Florida to adopt sustainable and inclusive practices for water quality improvement.

Water pollution scenarios and response options for China

China has formulated several policies to alleviate the water pollution load, but few studies have quantitatively analyzed their impacts on future water pollution loads in China. Based on grey water footprint (GWF) assessment and scenario simulation, we analyze the water pollution (including COD, NH3-N, TN and TP) in China from 2021 to 2035 under different scenarios for three areas: consumption-side, production-side and terminal treatment. We find that under the current policy scenario, the GWF of COD, NH3-N, TN, and TP in China could be reduced by 15.0 % to 39.9 %; the most effective measures for GWF reduction are diet structure change (in the consumption-side area), and the wastewater treatment rate and livestock manure utilization improvement (in the terminal treatment area). However, the GWF will still increase in 8 provinces, indicating that the current implemented policy is not universally effective in reducing GWF across all provinces. Under the technical improvement scenario, the GWF of the four pollutants will decrease by 54.9 %–71.1 % via improvements in the current measures related to current policies and new measures in the production-side area and the terminal treatment area; thus, GWF reduction is possible in all 31 provinces. However, some policies face significant challenges in achieving full implementation, and certain policies are only applicable to a subset of provinces. Our detailed analysis of future water pollution scenarios and response options to reduce pollution loads can help to inform the protection of freshwater resources in China and quantitatively assess the effectiveness of policies in other fields.

Community ecological response to polycyclic aromatic hydrocarbons in Baiyangdian Lake based on an ecological model

The dynamic response of a single population to chemicals can be represented by a Weibull function. However, it is unclear whether the overall response can still be represented in this manner when scaled up to the community level. In this study, we investigated the responses of biological communities to polycyclic aromatic hydrocarbons by using an ecological model of Baiyangdian Lake in northern China. The community dynamics process was divided into the following three stages. In the first stage, toxicity, played a dominant role and strong, medium, and weak species responses were observed according to the toxicity sensitivity. In the second stage, the dynamic process was dominated by the interaction strength with three alternative dynamic pathways comprising of direct response, no response, or inverse response. In the third stage, the toxicity was again dominant, and the biomasses of all species decreased to extinction. The toxicological dynamics were far more complex at the community level than those at the single species level and they were also influenced by the interaction strength as well as toxicity. The toxicological dynamic process in the community was constantly driven by the competing effects of these two forces. In addition to the total biomass, the interaction strength was identified as a suitable community-level signal because it exhibited good indicator properties regarding ecosystem steady-state transitions. However, we found that food web stability indicators were not suitable for use as community-level signals because they were not sensitive to changes in the ecosystem state. Some ecological management suggestions have been proposed, including medium to long-term monitoring, and reduction of external pollution loads and bioindicators. The results obtained in this study increase our understanding of how chemicals interfere with community dynamics, and the interaction strength and total biomass were identified as useful holistic indicators.

An optimization framework for basin-scale water environmental carrying capacity

The interaction between water environment and social economy at a basin scale is complex and challenging to quantify. To address this issue, this study proposes an integrated framework that builds parametric connections among water, contaminants, administrative regions, and social activities. The framework, known as the water environmental carrying capacity (WECC) optimization framework, effectively captures the intricacy of the interaction and integrates socio-economic parameter structure relationships, a water environmental model, a WECC optimization model, and a sensitivity analysis of regulatory parameters. Applied to the Anhui-Huaihe Basin in mid-eastern China, the framework considers nine administrative regions and three economic factors: industry, agriculture, and GDP per capita (pGDP). Results show that the current water environmental carrying capacity of the watershed is insufficient to meet socio-economic development requirements. After optimization, the WECC for industry, agriculture, and pGDP in the region increased by 22.40%, 26.59%, and 15.08% respectively. Overall COD and NH4–N discharge decreased by 13.6% and 14.7% respectively, effectively reducing pollution loads in rivers and enhancing sustainable development potential. At the regional scale, optimization for industry, agriculture, and pGDP exhibited different characteristics, but all aimed to improve efficiency by reducing the K value (pollution discharge/output value ratio). Regions with industrial treatment rates (αwt) below 0.8 should prioritize increasing treatment rates, while those above 0.8 should consider industrial upgrading for enhanced efficiency. For agriculture, important sensitive parameters for farming and livestock breeding are the proportion of high standard farmland (αs) and the scale breeding ratio (αb), which should be increased to above 0.15 and 0.83 respectively for all regions to achieve agricultural optimization. For pGDP optimization, the focus is on improving living environments and reducing pollution discharge, with crucial measures including collecting and treating rural domestic sewage, where the rural toilet improvement rate (αt) in each region should be increased to 0.78 or above. The results emphasize the need for both interregional allocation and intraregional planning to achieve comprehensive basin optimization and a harmonious balance between regional development and water environment.

INOVASI MEDIA FILTER BERBAHAN DASAR PASIR KWARSA DAN KARBON ORGANIK KULIT BUAH AREN UNTUK PROSES PENGOLAHAN AIR BERSIH DI PT. AIR MINUM INTAN BANJAR (PERSERODA)

Population growth requires the provision of clean water that meets the standards. As a provider of clean water. PT.Air Minum Intan Banjar (Perseroda) needs to continue to innovate in the water treatment process. One of them is in the filtration process. The purposes of the research were to analyze the thickness variations of the filter media from Quartz sand and palm sugar peel in the filtration process and to analyze the water resulted from the filtration process through laboratory tests. The variations of filter media thickness, namely: 30 cm, 40 cm, 50 cm, 60 cm and 1 control. The treatments were conducted with 20 repetitions which were taken randomly using the Complete Randomized Design (RAL) method. The samples from the treatment were analyzed in the laboratory to be compared to the parameters of Clean Water Standard from Permenkes RI No. 492 year 2010, namely: Turbidity, Color, TDS, pH, Fe, Mn, Nitrate, Nitrite, Sulfate, and E. Coli. The results of statistical data analysis showed that there was a significant change in the reduction of several pollutant loads through the filtration process using filter media from Quartz sand and organic carbon of sugar palm peels. The reduction of the pollutant loads especially in the thickness variation of 60 cm. The reduction of the pollutant loads is on several parameter, namely: Turbidity, Color, TDS, Fe, Mn, Nitrate, and Nitrite. However, the variation treatment of the thickness of the quartz sand filter media and the organic carbon of sugar palm peels at all thicknesses did not have significant change to the levels of pH, Sulfate and the amount of E. Coli between raw water and treated water in the filtration process.