絮凝沉淀-人工湿地-地下水回灌系统水质处理试验研究

为探讨德阳市絮凝沉淀-人工湿地-地下水回灌系统运行各阶段的水质处理效果与开采供水的可行性,开展了水质分析、絮凝沉淀试验、人工湿地水处理试验、入渗试验、抽水试验、数值模拟等多项前期试验与分析。试验结果显示,绵远河水的浊度、氨氮(NH+4-N)、总氮(TN)、总磷(TP)、化学需氧量(COD)、总大肠杆菌、细菌总数指标是系统重点处理的水质指标,研究场地内地下水质量总体良好;絮凝剂聚合氯化铝(PAC)的最佳投加量为5. 3 mg/L以三氧化二铝(Al2O3)计],沉淀时间不小于1. 5 h;单个入渗池运行时理论入渗量可达13 574. 4 m3/d;三口开采井的开采量可达3 960 m3/d;数值模拟结果显示入渗水从入渗补给池到开采井含水层有充足的时间杀灭病菌和病毒,开采井地下水的主要补给来源是入渗池的垂向入渗补给量。综合研究表明,系统运行水质主要控制指标理论上均可达到设计回灌水质要求,供水量可满足设计要求,对地下水环境造成影响较小,系统运行在技术上是可行的,但需要持续开采地下水;试验结果为校正地下水数值模型、系统的改进、系统全面运行提供了重要的参考。

Water quality treatment tests study on flocculation precipitation-wetland ecosystem-artificial groundwater recharge system

A number of preliminary tests, such as water sampling, flocculation and precipitation test, artificial wetland water treatment test, infiltration test, pumping test and groundwater numerical simulation, are applied to analyze the water treatment effect of each stage and water supply feasibility of the wetland-artificial groundwater recharge system. Test results show that, the turbidity, NH4+-N, TN, TP, COD, total coliform group and total number of bacteria are the key indices which are needed to be treated. Groundwater quality in the research field in good. The appropriate dosage of PAC is 5.3 mg/L (mearued by Al2O3). The infiltration capacity of single infitration pond can reach 13574.4m3/d. The total discharge of three wells can reach 3960m3/d. Numerical simulation results show that there are enough time to kill pathogens and viruses in the water which is from infiltration pond to mining well. The main source of groundwater recharge in the mining wells is the vertical infiltration recharge from the infiltration pond. Comprehensive studies shows that the main control indices of the water quality, theoretically, can meet the design artificial recharge requirements afer treatment, and the groundwater yield of wells can meet the design requirements. Small impact on groundwater environment is caused by the system operation, and the operation of the system is technically feasible, but groundwater needs to be continuously exploited. The test results provide an important reference for the correction of numerical model of groundwater, the improvement of the recharge system and the overall operation of the system.