草地利用农村生活污水过程中土壤溶液污染物迁移规律研究OA

To elucidate the distribution patterns and correlations of pollutant concentrations in grassland soil solution during the utilization of rural domestic wastewater,and to provide a scientific basis for risk management in rural wastewater reclamation,an outdoor grassland experiment was conducted.The study investigated the effects of hydraulic loading on grassland soil organic matter,microbial α diversity,and concentrations of chemical oxygen demand(COD),total nitrogen(TN),and total phosphorus(TP)in soil solution.The variations of soil organic matter and soil solution COD,TN,and TP in both horizontal and vertical dimensions were analyzed,along with their Pearson correlation coefficients(r).The results revealed that increasing the hydraulic load contributed to a decrease in the concentrations of COD and TP in the lower soil solution and an increase in microbial diversity of the grassland system,but also led to a reduction in the average soil organic matter content and an elevation in TN concentration in the lower soil solution.A strong positive correlation(r>0.6)was observed between TN and TP concentrations in the soil solution along the vertical profile,and part of the nitrogen and phosphorus nutrients utilized by the grassland originated from the upward migration of inorganic nitrogen and phosphorus from the deeper soil layers.In the process of utilizing rural domestic wastewater for grassland assimilation,a hydraulic load of 0.005 m³/(m²·d)was identified as appropriate;exceeding this load would increase the risk of TN accumulation and leaching.This study provides a scientific basis for the safe resource utilization and environmental risk management of rural domestic wastewater,and holds important practical value for advancing rural domestic wastewater treatment and the recycling of water and nutrient resources.