污泥过滤过程中滤速影响因素的试验研究

Influence factors on filtration rate in sludge filtration process

针对生物膜法出水悬浮固体偏高的问题,通过对水处理中慢滤池和滤饼过滤原理的借鉴,将生物滤池引入生物膜反应器,利用游离的活性污泥和部分脱落的生物膜及颗粒滤料组成污泥过滤层进行过滤出水以提高出水水质.在分析污泥滤层的过滤机理及滤速的主要影响因素的基础上,试验研究了滤料粒径、污泥浓度和初滤速对污泥过滤滤速的影响.试验结果表明,在滤料粒径为0 8～2 2mm,污泥浓度不大于1200mg·L-1,初滤速小于2 5m·h-1的情况下,污泥过滤平均滤速可保持在0 3～1 0m·h-1,与SBR法的沉淀、滗水时间持平,且不会产生污泥穿透现象,出水浊度均小于10NTU,具有应用的可行性.污泥主要集中在滤料表层.由于采用慢速表面过滤,滤速相对较小,滤料层中截留的悬浮固体在孔隙中堵塞的强度较弱,采用强度较低的非膨胀反冲洗即可.

Sludge filtration, composed of free activated sludge, detached biofilm and granule media, was used to diminish suspend solid (SS) in effluent of Sequencing Batch Biofilm Reactor (SBBR) on the principle of slow filter and cake filtration. On the basis of analyzing mechanism of sludge filtration and main influence factors of filtration rate, experimental studies on influences of media granule, sludge concentration and initial filtration rate on sludge filtration rate was carried out. The experimental results showed that average filtration rate could be maintained at 03～10?m·h-1 with granule diameters between 08～22?mm, sludge concentration below 12?g·L-1 and initial filtration rate under 25?m·h-1, and the duration was equivalent to that of settling and drawing of SBR process. The sludge penetration phenomenon would also be inhibited simultaneously. The turbility of effluent were all below 10?NTU. Sludge mainly enriched on the surface of media layer, and slow surface filtration was proceeded. Nonbulking backwashing, which backwashing intensity was low, would be introduced because the clog intensity of suspend solid in media layer was low and filtration rate was not high.