反冲洗强度对生物除铁除锰滤池去除效果的影响

Influence of Backwashing Intensity on Removal Efficiency in a Biological Iron and Manganese Removal Filter

反冲洗强度是生物除铁除锰滤池的一个重要运行参数。采用成熟稳定的滤柱，分别设定反冲洗强度为14、11、8L／（S·m^2），考察反冲洗强度变化对铁、锰、氨氮、浊度去除效果的影响。结果表明，在不同反冲洗强度下，滤柱对铁、锰、氨氮均有很好的去除效果，出水中的总Fe、Mn^2＋、Nn4^＋ -N平均浓度分别为（0.015、0.014、0.013）、（0.003、0.001、0）、（0.022、0.017、0.016）mg／L，均优于国家标准，即反冲洗强度对三者的去除效果没有影响。出水平均浊度分别为0.28、0.41、0.55NTU，反冲洗强度越小则出水浊度越高；并且浊度主要在0～0.4 m滤层被去除，出水浊度与滤层厚度无关。反冲洗5min后出水浊度为24.6NTU，20min时降到了0.85NTU，50min后降到了0.43NTU，90min后大约恢复到反冲洗前的水平。

Backwashing intensity is one of the most critical operational parameters for biological iron and manganese removal filter. In order to investigate the effect of backwashing intensity on the removal efficiency of iron, manganese, ammonia nitrogen and turbidity in a mature filter, three backwasbing intensities of 14, 11 and 8 L/（ s · m^2） were adopted. High removal efficiencies of iron, manganese and ammonia nitrogen in different backwashing intensities were found in the results, and the average concentrations of the total iron, manganese and ammonia nitrogen in the effluent using the backwashing intensities 14, 11 and 8 L/（s · m^2） were 0.015 rag/L, 0.014 mg/L and 0.013 mg/L; 0.003 mg/L, 0.001 mg/L and 0 rag/L; and 0.022 rag/L, 0.017 mg/L and 0.016 mg/L, respectively. Each clearly satisfied the national standard, which illustrated that varying backwashing intensities had no influence on the removal efficiency. The average turbidity in the effluent was 0.28 NTU, 0.41 NTU and 0.55 NTU when the backwashing intensity was 14, 11 and 8 L/（ s· m^2）, respectively. Lower backwashing intensity corresponded to higher turbidity in the effluent. Turbidity was mainly removed in the 0 to O. 4 m filter layer, and turbidity in the effluent had no relation to the height of the media. Turbidity in the effluent was 24.6 NTU 5 minutes after backwashing, then decreased to 0.85 NTU in 20 minutes, 0.43 NTU 50 minutes later, and to the level of initial backwashing 90 minutes later.