3种基质材料对高浓度养殖废水处理效果及降解过程

养殖场直排废水负荷高,易造成湿地植物无法生长、处理效率低等问题.为使养殖废水通过前端生态治理技术,出水达到湿地植物耐受范围,探索高效利用作物秸秆,降低污染负荷的可行性,开展野外控制实验,对比分析了三大粮食作物秸秆——麦秸、稻草和玉米秆对猪场废水N、P的吸附去除效率.三级基质池各填充12. 5 kg干秸秆,设定连续式进水,水力停留时间7 d.结果表明,在进水COD、TN、NH_4~+-N、NO_3~--N和TP平均质量浓度分别为1 652. 83、371. 31、303. 51、0. 67和65. 22 mg·L~(-1)时,麦秸对COD、TN和TP的去除效果最好,去除率分别为32. 1%、40. 9%和33. 3%,稻草对NH_4~+-N的去除效果最好,去除率达到43. 4%.经180 d处理后3种基质材料木质素、纤维素和半纤维素均未完全分解.各种基质材料木质素降解速率低于纤维素与半纤维素,且稻草中木质素和纤维素降解最快,麦秆中半纤维素降解最快.结果表明,麦秆和稻草对去除高浓度养殖废水污染物效果均好于玉米秆,并且建议基质材料更换周期为5个月,可为生物基质材料运用于养殖废水处理提供数据支撑.

Treatment of Highly Concentrated Swine Wastewater and Its Degradation Processes Using Three Matrix Materials

The direct discharge of wastewater from pig farms can restrict wetland plant growth meaning that constructed wetlands (CWs) have generally low treatment efficiency. The treatment of farming wastewater using pre-ecological treatment technologies can be used to ensure that effluent concentrations reach the tolerable limits of wetland plants. This study focused on the efficient use of crop straw for reducing the pollution load of swine wastewater. Using field-scale pilot tests, wheat straw, straw, and corn stalk were used as test biological matrix pool fillers to treat the farming wastewater. Continuous intake of wastewater and a hydraulic retention time of 7 days was adopted. When the average concentrations of COD, TN, NH₄⁺-N, NO₃^--N, and TP in the influent were 1652.83 mg·L^-1, 371.31 mg·L^-1, 303.51 mg·L^-1, 0.67 mg·L^-1, and 65.22 mg·L^-1, respectively, wheat straw had the greatest removal effect on COD, TN, and TP, achieving a removal rate of 32.1%, 40.9%, and 33.3%, respectively. The removal efficiency of straw on NH₄⁺-N was highest, reaching 43.4%. After 180 days, the lignin, cellulose, and hemicellulose of the three matrix materials were not completely decomposed. The degradation rate of lignin was lower than for cellulose and hemicellulose; the degradation of lignin and cellulose in the straw was fastest; and the degradation hemicellulose in wheat straw was fastest. The results show that wheat straw and straw offer a higher efficiency treatment for swine wastewater than corn stalk, and the suggested replacement cycle period is five months. These results provide initial data to support the application of biological matrix materials in the treatment of swine wastewater.