农村生活污水处理设施出水排放对湖荡水质影响分析

Analysis on influence of effluent from domestic sewage treatment facility in the rural area on water quality of lake wetlands

为探究嘉兴市下辖农村生活污水处理设施出水排放对湖荡水质的影响,于2019年6月采集44个湖荡的上覆水、沉积物和间隙水样品,并将湖荡及附近160个污水处理设施区域划分为9个区域,分析了各区域污水处理设施出水对湖荡水质的影响。结果表明,研究区域夏季湖荡水体污染严重,上覆水化学需氧量(COD)、氨氮(NH_(3)-N)、总氮(TN)、总磷(TP)质量浓度均值分别为6.58、1.38、2.47和0.27 mg/L,间隙水的4项指标分别为51.12、18.13、30.32和0.58 mg/L,大部分湖荡为劣Ⅴ类水体。研究区域上覆水COD与间隙水COD呈极显著正相关(p<0.01),间隙水NH_(3)-N与沉积物TN呈极显著正相关(p<0.01),上覆水TN和TP浓度与设施出水排放氮磷浓度均呈显著正相关(p<0.05),与氮磷去除率呈显著负相关(p<0.05),表明农村生活污水处理设施氮磷去除率对湖荡上覆水中氮磷营养盐浓度存在影响。

In June 2019, overlying water, sediment, and pore water samples from forty-four lake wetlands were collected to explore the relevance of effluent from 160 domestic sewage treatment facilities(DSTF) on water quality in lake wetlands. The study area was divided into 9 sections, and the influence of effluent from DSTF on water quality in lake wetlands was analyzed. The results indicated that the pollution from nitrogen and phosphorus was serious, and the average mass concentrations of chemical oxygen demand(COD), ammonia nitrogen(NH_(3)-N), total nitrogen(TN), and total phosphorus(TP) in overlying water were 6.58, 1.38, 2.47 and 0.27 mg/L, respectively. The ones in pore water were 51.12, 18.13, 30.32 and 0.58 mg/L, respectively, and the water quality of most lake wetland was standard Ⅴ grade. The correlation analysis of pollutants between overlying water, pore water, and sediment indicated that COD in overlying water had significant positive correlation with the one in pore water(p<0.01), and NH_(3)-N in pore water had significant positive correlation with TN in sediment(p<0.01). In the study area, the TN and TP concentrations in lake wetlands had positive correlation with the effluent from DSTF(p<0.05). The nitrogen and phosphorus removal rate in DSTF in the rural area had an effect on nitrogen and phosphorus concentrations in the overlying water from lake wetlands.