Cr^(6+)对一体式MBR污泥性状及处理效果的影响

Influence of Chromium (Ⅵ) on Activated Sludge in the Membrane Bioreactor

以添加了Cr6+的生活污水为原水,从宏观及微观角度研究了Cr6+对一体式膜生物反应器(MBR)污泥处理系统的影响。结果发现30 mg/L的Cr6+可使污泥较快呈现中毒症状,污泥的呼吸速率(OUR)、MLSS明显降低,污泥系统几乎丧失对COD的降解能力,但仍具有一定的硝化能力;MBR的出水COD在短期内不受MBR中污泥活性的影响,即使污泥已经中毒,MBR仍具有较高的COD去除能力;Cr6+破坏了MBR污泥正常菌群对进水中微生物的优势生态结构,使外源微生物(由进水提供)的数量明显增多,但对其中的可培养真菌和细菌及硝化细菌数目具有不同的影响。

Taking the domestic wastewater with increased chromium （ Ⅳ ） concentration as raw water, the influence of different chromium （ Ⅳ ） concentration on the activated sludge treatment system was investigated in the membrane bioreactor （MBR）. The results show that 30 mg/L of chromium （Ⅳ） has serious toxicity effects on activated sludge. The values of OUR and MLSS decline evidently. The abil- ity of COD removal by activated sludge becomes ineffectual, but the nitrification ability remains in the system. The toxicity of sludge does not reduce the COD removal efficiency in the MBR, meaning the state of activated sludge does not produce any effects on the effluent in a short time. Chromium （ Ⅳ ） destroys the ecological balance between activated sludge in the MBR and microorganisms in domestic wastewater, resulting in a marked increase in quantity of varied microorganisms from wastewater. However, chromium （ Ⅳ ） has different effects on the amount of culturable bacteria, fungus and nitrobacteria.