底物种类和浓度对好氧颗粒污泥丝状菌膨胀的影响

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

    • 摘要: 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 granular sludge,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.

       

      Abstract: 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.

       

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