污泥停留时间对SMBR净化受污染水源水的影响

Influence of sludge retention time on submerged membrane bioreactor for treating polluted raw water

摘要:

为考察用于饮用水处理的浸没式膜生物反应器(SMBR)中适宜的污泥停留时间(SRT),在平行运行的条件下对比研究了80d和20d两种SRT下SMBR净化受污染水源水的效能.结果表明,在80d的SRT下,SMBR对DOC、UV254、TOC、CODMn的去除率分别为19.6%、13.4%、27.7%和30.7%;而当SRT为20d时,SMBR的平均去除率为21.2%、13.2%、29.2%和32.7%,去除能力基本相同.此外,80d和20d两种SRT下SMBR对NH3-N的去除率均高于96%.而采用20d的SRT时,SMBR的跨膜压增长速率略低于80d的情况.可见,将SRT由80d缩短至20d,不仅不会对SMBR净化受污染水源水的效能产生影响,还有助于减缓膜污染.这样,就可以考虑在SMBR中直接投加粉末炭以强化对有机物的去除,并及时排泥,使反应器中的污泥浓度维持在适宜的范围内.

Abstract:

To evaluate the suitable sludge retention time(SRT)in submerged membrane bioreactor(SMBR) for drinking water treatment,two SMBRs under the SRT of 80 d and 20 d were run in parallel and compared in terms of the effectiveness for treating polluted raw water.The results showed that under the SRT of 80 d,the removal efficiencies of SMBR for DOC,UV 254,TOC,COD Mn were 19.6%,13.4%,27.7%and 30.7%,while those under the SRT of 20 d were 21.2%,13.2%,29.2%and 32.7%,respectively.Furthermore,both of the SMBRs achieved over 96%of removal for influent NH3-N.However,when the short SRT(20 d) was employed,the development rate of trans-membrane pressure in SMBR was lower than that under long SRT(80 d).Therefore,the reduction of SRT from 80 d to 20 d would not affect the effectiveness of SMBR for treating polluted raw water,but mitigate the membrane fouling in SMBR.With the short SRT,it would be possible to dose powdered activated carbon directly in the SMBR,in which the sludge withdrawal could be performed periodically,to maintain the sludge concentration in suitable range.