分段进水对深层床潮汐流人工湿地硝化-反硝化性能的影响

Effect of Step-Feeding on Nitrification and Denitrification Characteristics of A Deep Bed Tidal Flow Constructed Wetland System

为了克服传统人工湿地占地面积大、TN去除率低的问题,采用深层床潮汐流人工湿地系统处理生活污水。结果表明,未分段进水条件下(水力负荷为0.42 m^3/(m^2·d)),COD和NH4^+-N平均去除率分别为82.28%和98.28%;分段进水条件下(水力负荷0.53 m^3/(m^2·d)),COD与NH_4^+-N均去除率分别为67.10%和99.48%。随着分段进水的设置,出水TN的质量浓度平均由53.22 mg/L降低至19.23 mg/L,平均去除率由33.74%升高至70.77%;在设置分段进水点的第2级人工湿地单元,硝化速率由14.40 g/(m^3·d)提高至38.39 g/(m^3·d),反硝化速率由2.79 g/(m^3·d)提高至20.96 g/(m^3·d)。在工况2条件下,每处理1 m3的生活污水需要的占地面积为1.88 m^2,仅为传统人工湿地占地面积的12.37~18.80%。

In order to reduce the land occupied so as to achieve a higher degree of TN removal, a deep bed tidal flow constructed wetland （DB-TFCWs） was developed for domestic wastewater treatment. Results shows that, the COD and NH4＋-N removal rate reached 82.28% and 98.28% in a unsegmented condition where the hydraulic loading was 0.42 m3/（m2.d）.; However, the COD and NH4＋-N removal rate reached 67.10% and 99.48% in a segmented condition where the hydraulic loading was 0.53 m3/（m2·d）. Along with the step-feeding setting, the average effluent mass concentration ofTN droped from 53.22 mg/L to 19.23 mg/L, and the average removal efficiencies increased from 33.74% to 70.77%. In the side input stage （stage 2）, the nitrification rate increased fIom 14.40 g/（m3.d） to 38.39 g/（m3·d）, and the denitrification rate increased from 2.79 g/（m3·d） to 20.96 g/（m3.d）. The floor space of DB- TFCWs treating 1 m3 domestic wastewater was 1.88 m2, which was 12.37- 18.8% of traditional conslnacted wetland throughout the period 2 operation time.