大型循环水池塘养殖系统氮磷污染控制绩效评估

Performance assessment of large-scale recirculating aquaculture system on nitrogen and phosphorous pollution control

循环水池塘养殖系统现已成为太湖流域水产养殖的重要形式。主要针对某大型循环水池塘养殖系统的水质状况进行了调查,并对氮磷污染控制绩效进行了评估。结果表明:人工湿地、生态沟渠和养殖池塘水体总氮平均浓度分别为0.887、1.263和1.745 mg·L^(-1),人工湿地、生态沟渠和养殖池塘水体总磷的平均浓度分别为0.097、0.081和0.169 mg·L^(-1)。该系统内养殖池塘水体总氮达到《太湖流域池塘养殖水排放标准(DB32/T 1705-2001)》的二级排放标准(TN≤3.0mg·L^(-1)),总磷均达到一级排放标准(TP≤0.3 mg·L^(-1));人工湿地和生态沟渠水体总氮和总磷均达到《太湖流域池塘养殖水排放标准》的一级排放标准(TN≤2.0 mg·L^(-1),TP≤0.3 mg·L^(-1))。分别采用物料平衡法和化学分析法估算出养殖池塘原始氮磷污染负荷和系统最终氮磷污染负荷。养殖池塘原始氮磷污染负荷分别约为152.66 kg·hm^(-2)(20.46 t·a^(-1))和32.52 kg·hm^(-2)(4.36 t·a^(-1)),系统最终氮磷污染负荷分别约为2.72和0.15 t·a^(-1)。该大型循环水池塘养殖系统运行情况良好,循环水池塘养殖系统具有良好的自我氮磷污染削减功能,适合作为以后构建水产养殖系统的模式。

Recirculating aquaculture systems have already developed into an important part of aquaculture in the Taihu Lake watershed. The water quality of a large-scale recirculating aquaculture system was investigated,and the N and P pollution loads were estimated to evaluate the control performance of the system. The average TN concentrations in the constructed wetland,ecological ditch,and aquaculture pond were 0. 887,1. 263,and 1. 745mg·L-1,respectively,and the average TP concentrations were 0. 097,0. 081,and 0. 169 mg·L-1,respectively. TN in the aquaculture pond satisfied the secondary standard value of Water Quality Standards of Aquaculture Discharge in Taihu Lake Watershed（ DB32/T 1705-2001）（ TN≤3. 0 mg·L-1）,and TP satisfied the primary standard value（ TP≤0. 3 mg·L-1）. TN and TP in the constructed wetland and ecological ditch reached the primary standard（ TN≤2. 0 mg·L-1,TP≤0. 3 mg·L-1）. Mass balance and chemical analysis methods were used to estimate the original and final N and P pollution loads. The original N and P pollution loads of the aquaculture pond were 152. 66 kg·hm-2（ 20. 46 t·a-1） and 32. 52 kg·hm-2（ 4. 36 t·a-1）,respectively,whereas the final N and P pollution loads of the whole system were only 2. 72 t·a-1and 0. 15 t·a-1,respectively. The largescale recirculating aquaculture system ran well and controlled N and P pollution by itself. The recirculating aquaculture model is suitable for further popularization.