污水灌溉与污水土地处理系统试验及模拟仿真研究

Trial and simulation of a pilot system combining wastewater land treatment with crop irrigation

为解决大面积不加控制的污水灌溉和未经处理的污水自由排放造成的地表水体污染问题,提出了由作物生长季节污水灌溉、低温季节污水储水入渗和地下水管理3个子系统构成的污水灌溉与污水土地处理系统。对污水灌溉子系统污染物去除效果和污水储水入渗子系统冬季工作状况进行了试验研究,利用MODFLOW模型对地下水管理子系统运行效果进行了模拟,探讨了污水灌溉与污水土地处理系统的运行性能及其对地下水的影响。结果表明:在作物生长季节内,污水灌溉子系统可有效提高系统水力负荷、污染物去除效果良好、对地下水水质无显著影响;在无作物生长的冬季,污水储水入渗子系统可保持冰层下污水持续入渗,确保低温下污水土地处理系统的正常运行;通过采用适当的地下水管理调控措施,可避免高定额污水灌溉和储水入渗对地下水产生的潜在不利影响,达到地下水管理子系统控制范围内地下水水量平衡。

To solve the problems of uncontrolled large scale wastewater irrigation and direct discharge of wastewater into surface water bodies, a system of wastewater irrigation and wastewater land treatment was contrasted, which was composed of wastewater irrigation during crop growth stage, wastewater storage and infiltration during the winter and groundwater management. The experiments of pollutant removal and wastewater storage and infiltration in the winter were conducted. A model based on MODFLOW was used to simulate the operation effect of groundwater management and to analyze the effects of operation property of wastewater irrigation and wastewater land treatment system on the groundwater. The results show that the hydraulic load of wastewater irrigation system is increased, pollutant removal effect is better and the groundwater quality is not influenced by system during the crop growth stage. Wastewater storage and infiltration during the winter could keep continuous infiltration of wastewater below the ice to ensure the operation of the system at lower temperation. By measures of groundwater management, potential adverse impact of wastewater irrigation and land treatment on the groundwater can be avoided to realize the groundwater balance for the sub-system of groundwater management.