铬离子对SBR工艺活性污泥毒性作用研究

针对重金属铬离子对SBR工艺系统中活性污泥的毒性作用,通过检测不同初始污泥容积指数(SVI)下SBR工艺活性污泥在不同铬负荷下的COD值、挥发性污泥浓度以及受铬离子影响的污泥容积指数(SVI),研究重金属铬离子对活性污泥的毒性作用以及对SBR工艺系统处理污水的影响。研究表明,重金属铬离子会导致SBR工艺系统出水COD升高;将铬离子对活性污泥的毒性作用按照挥发性污泥(MLVSS)铬负荷可划分为耐受范围、非耐受范围、细胞失活范围以及细胞分解范围。耐受范围铬负荷低于约30 mg Cr3+/gMLVSS,此范围内铬离子对于活性污泥的毒性作用不大,不致于导致系统出水水质变差;非耐受范围铬负荷在约30~65 mg Cr3+/g MLVSS,在铬离子作用下系统出水COD值明显高于对照系统;细胞失活范围铬负荷在约70~100 mg Cr3+/gMLVSS范围内,SVI大幅下降,微生物部份死亡和失活,出水COD尽管有一些下降,但与进水COD相比差不了多少;细胞分解范围铬负荷在约100 mg Cr3+/gMLVSS以上,微生物大量死亡,部分死亡细胞分解,系统出水COD值因微生物的死亡分解而超出进水COD值,受铬离子影响的系统SVI值大幅度降低。

Study on toxicity of chromium ion to activated sludge in SBR process

Aimed at the toxicity of the chromium ion to the activated sludge in the SBR system, by the determination of COD value, the sludge concentration, the SVI influenced by chromium ion in the SBR system of the different primary SVI, the toxicity of the chromium ion to the activated sludge and the influence on the SBR system treating the wastewater were studied. It was found that the chromium ion would cause the effluent COD value of the SBR process increase. The chromium toxicity to the activated sludge was divided four scopes according to the chromium load based on MLVSS: tolerance range, non-tolerance range, cell inactivation range and cell disintegration range. The chromium load which was below about 30 mg Cr~(3+)/g MLVSS was called tolerance range,in which range the toxicity of chromium ion to the activated sludge had little influence, and not caused the effluent quality become bad. The chromium load which was about between 30 mg Cr~(3+)/g MLVSS and 65 mg Cr~(3+)/g MLVSS was called non-tolerance range, in which range the effluent COD of the system influenced by the chromium ion was bigger than which of the control system. The chromium load which was about between 70 mg Cr~(3+)/g MLVSS and 100 mg Cr~(3+)/g MLVSS was called cell inactivation range,in which range the SVI value decreased obviously, a part of microbe became dead and lost their biological activities, the sludge system had aleady lost its ablitily of treating wastewater,although the effluent COD decreased a bit, it was close to the influent COD. The chromium load which was above about 100 mg Cr~(3+)/g MLVSS was called cell disintegration range, in which range the microbe died a great deal, and the dead microbe began to disintegrate, not only the effluent COD was overstepped the influent COD,but also the SVI value of the activated sludge system influenced by the chromium ion decreased obviously.