反冲洗周期对生物除锰滤池去除效果的影响

Influence of backwashing period on removal efficiency in a biological manganese removal filter

反冲洗周期是生物除铁除锰滤池的一个重要运行参数，实验中分别设定反冲洗周期为24、48和72h，考察反冲洗周期对成熟稳定运行的滤柱出水铁、锰、氨氮和浊度的影响。结果表明，不同反冲洗周期，滤柱对铁、锰和氨氮均有很好的去除效果，出水中的总Fe、Mn“和NH？-N的平均浓度分别为0．018、0．003和0．016mg／L，0．010、0．001和0．014mg/L，0．013、0．001和0．014mg／L，均远低于国家标准，说明反冲洗周期变化对三者的去除效果没有影响。反冲洗周期为24、48和72h时，出水平均浊度分别为0．27、0．38和0．57NTU，反冲洗周期越长，出水浊度越高。滤柱沿程浊度分析发现，浊度主要在0～O．4m去除，出水浊度与滤层厚度无关。反冲洗后5rain出水浊度为3．16NTU，15min降到了1NTU以下，25min降到了0．5NTU，60min大约降到了反冲洗前的水平。

Backwashing period is one of the most critical operational parameters for biological iron and manganese removal filter. In order to investigate the effect of backwashing period on iron, manganese, ammonia and turbidity in effluent of mature filter, three backwashing periods were adopted with 24 h, 48 h, 72 h. Results showed that total iron, manganese and ammonia had a high removal rate in different backwashing periods, the average concentration of total iron, manganese and ammonia in effluent were 0. 018,0. 003 and 0. 016 rag/L, 0. 010,0. 001 and 0. 014 mg/L,0. 013,0. 001 and 0. 014 mg/L,respectively. Each of them was better than the national standard, which illustrated that varying backwashing period had no influence on the removal efficiency of them. The turbidity in effluent was 0.27 NTU, 0.38 NTU, 0.57 NTU, respectively, when the backwashing pe- riods were 24 h, 48 h, 72 h. The longer backwashing period, the higher turbidity in effluent. Turbidity was mainly removed in 0 - 0.4 m, and the turbidity in effluent had nothing to do with the height of the media. The turbidity in effluent was 3.16 NTU 5 minutes after backwashing, then decreased to less than 1 NTU 15 minutes later, and droped to less than 0.5 NTU in 25 minutes, finally the turbidity decreased to the level of initial back- washing 60 minutes later.