复合人工湿地处理生活污水的冬季启动和春季运行

Winter Start-up and Spring Operation of Hybrid Constructed Wetland for Domestic Sewage Treatment

以北方某城镇生活污水为实际进水,研究了垂直流+水平流复合人工湿地(HCW)系统的冬季启动和春季运行情况,通过低温条件下曝气工况的变化,探讨强化曝气对HCW冬季启动和春季运行时污染物去除及植物生长的影响。结果表明,在冬季低温启动阶段及春季运行阶段,曝气均明显提高了HCW系统的溶解氧浓度,从而提高了对生活污水中COD、SS、TN、NH_(4)^(+)-N和TP的去除效果。此外,即使在气温为(0.3±2.4)℃、水温为(7.25±2.7)℃的条件下,HCW系统的植物分蘖并未停止,植物株高也继续增长。因此,从植物的分蘖和株高变化来看,HCW系统的启动在冬季不受低温影响。冬季启动后的HCW系统在春季运行,出水SS和COD浓度均达到了《城镇污水处理厂污染物排放标准》(GB 18918—2002)的一级A标准,出水NH_(4)^(+)-N和TN浓度分别为(6.81±1.01)、(15.48±1.34)mg/L。

The winter start-up and spring operation of a hybrid constructed wetland(HCW) consisted of a vertical flow constructed wetland(VFCW) and a horizontal flow constructed wetland(HFCW) fed domestic sewage from a northern town was investigated. Meanwhile, the effects of enhanced aeration on pollutant removal and plants growth of the HCW during winter start-up and spring operation were explored by changing the aeration conditions at low temperature. During the cold start-up stage in winter and the operation stage in spring, aeration obviously increased the dissolved oxygen in the HCW system, so as to improve the removal performance of COD, SS, TN, NH_(4)^(+)-N and TP in the domestic sewage. In addition, tillering did not stop and plant height continued to increase in the HCW system even at low air temperature of(0.3±2.4) ℃ and water temperature of(7.25±2.7) ℃. Therefore, the start-up of HCW system was not affected by low temperature in winter as showed by the changes of tillering and plant height. During the operation of the HCW system in spring, the SS and COD in the effluent reached the first level A criteria specified in Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant(GB 18918-2002), and the NH_(4)^(+)-N and TN in the effluent were(6.81±1.01) mg/L and(15.48±1.34) mg/L, respectively.