土著微生物原位梯级修复地下水氮污染的数值模拟研究

土著微生物作为微生物群体类型之一, 在降解地下水硝酸盐方面发挥着重要作用, 具有成本较低、基本不产生二次污染等优点。文章基于已开展的矩形槽修复试验数据和模型结构, 建立地下水数值模拟模型, 通过联合水流和溶质运移模型, 确定梯级修复不同距离处对应的最大氨氮负荷、硝酸盐负荷和水力负荷。结果表明: 以地下水Ⅲ类标准值作为约束条件, 当补给强度为 0.68 m/d 时, 模拟区范围内可以承载的氨氮、硝酸盐污染物最大负荷为 18.05、54.14 g/(m²·d); 氨氮质量浓度为 15 mg/L、硝化作用 20 cm 区段内的最大水力负荷为 1.62 m³/(m²·d), 硝酸盐质量浓度为 40 mg/L 时的最大水力负荷为 1.14 m³/(m²·d)。该研究结果以期为地下水的原位硝酸盐污染修复和治理提供技术参考。

As a type of the microbial community, indigenous microorganisms play an important role in degrading nitrate in groundwater, which has the advantages of low cost and basically no secondary pollution. In this paper, a numerical simulation model of groundwater was established based on the experimental data and model structure of the rectangular tank remediation, and the maximum ammonia nitrogen load, nitrate load and hydraulic load corresponding to the different distances of the cascade remediation were determined by combining the flow and solute transport models. The results show that the maximum loads of ammonia nitrogen and nitrate pollutants in the simulated area are $ 18.05 \, \text{g}/(\text{m}^2 \cdot \text{d}) $ and $ 54.14 \, \text{g}/(\text{m}^2 \cdot \text{d}) $ when the recharge intensity is 0.68 m/d with the Class III standard value for groundwater as the constraint condition. The maximum hydraulic load in the 15 mg/L ammonia nitrogen and 20 cm nitrification zone is $ 1.62 \, \text{m}^3/(\text{m}^2 \cdot \text{d}) $, and the corresponding maximum hydraulic load is $ 1.14 \, \text{m}^3/(\text{m}^2 \cdot \text{d}) $ when nitrate concentration is 40 mg/L. These findings are expected to provide technical reference for remediation and treatment of in situ nitrate pollution in groundwater.