底物种类和浓度对好氧颗粒污泥丝状菌膨胀的影响

在序批式反应器(sequencing batch reactor,SBR)内以蔗糖为底物培养好氧颗粒污泥(aerobic granularsludge,AGS),考察了底物种类和浓度对AGS培养和稳定维持的影响.在反应器运行的最初阶段,以蔗糖为唯一碳源,进水ρ(COD)为600~900 mg/L,10 d后形成了结构较为密实的AGS,平均粒径为1.15±0.14 mm,污泥指数SVI在90 mL/g左右;AGS稳定维持23 d后,ρ(COD)由900 mg/L增加到1 200 mg/L,AGS表面出现了大量丝状菌,AGS平均丝状化程度Δ值最大达到了1.69±0.23 mm,SVI增加至175 mL/g.为克服AGS丝状菌膨胀,以蔗糖+蛋白胨(1∶1)的混合底物代替单一底物,AGS表面的丝状菌逐渐减少,34 d后AGS表面"光滑",AGS丝状菌膨胀得到抑制,Δ值逐步下降至1.00±0.01 mm.ρ(COD)从600 mg/L增加至1 200 mg/L,AGS依旧保持稳定,未出现丝状菌大量繁殖的现象.本研究表明,单一底物培养AGS在负荷较高时容易出现丝状菌膨胀,而混合底物可以抑制AGS丝状菌膨胀,有利于AGS的稳定维持.

The Effects of Substrate Type and Concentration on Filamentous Growth in Aerobic Granular Sludge SBR

The effects of substrate type and concentration on cultivation and stability of aerobic granular sludge are investigated.During start-up phase,sucrose is used as the sole substrate,compact aerobic granular sludge form in 10 days under influent COD concentration of 600-900 mg/L,the mean diameter of the granule is 1.15±0.14 mm,SVI is 90 mL/g.However,when the influent COD concentration is increased from 900 to 1 200 mg/L,outgrowth of filamentous bacteria in aerobic granular sludge occur,when SVI is increased to 175 mL/g and large amounts of aerobic granular sludge are washed out of the reactor.In order to control the filamentous growth in aerobic granular sludge,sucrose+peptone(1∶1) are used as the substrate under influent COD concentration of 600 mg/L,during 34 days,the filamentous bacteria gradually disappear,the filamentous growth aerobic granular sludge transits to stable smooth aerobic granular sludge again.When the influent COD concentration is increased from 600 mg/L to 1 200 mg/L,non-filamentous bacteria prevail and aerobic granular sludge are stable.This study shows that substrate diversity and increased substrate N/COD ratio leads to the control of filamentous growth in aerobic granular sludge.