A/O MBR处理印染废水中进水pH值对降解性能的影响

采用厌氧好氧膜生物反应器(A/OMBR),系统考察了当进水pH值在5.0～9.0范围变化时,各反应槽的活性污泥对活性艳蓝KNR染料及COD的降解性能变化情况.从而探索出在厌氧与好氧微生物协同作用下,微生物对染料及有机污染物的降解性能不受明显影响的进水pH值波动范围,为降低实际印染废水处理中化学试剂的使用量提供理论依据.结果表明,只有当进水pH值为9.0时,厌氧槽对脱色率的贡献大于好氧槽,而当进水pH值在5.0～8.0范围内变化时,好氧槽对系统脱色率的贡献大于厌氧槽.进水pH值对厌氧活性污泥的COD的去除效果几乎没有影响,而中性及偏酸性的进水条件更有利于好氧活性污泥对COD的降解.在偏碱性的进水条件下,膜对可溶性COD的截流作用更明显.当进水pH值在5.0～9.0范围内变化时,由于厌氧槽的pH值都能够稳定在6.0附近,使好氧槽和系统出水的pH值能够分别保持在7.0和7.5附近,从而保证了整个系统对染料及COD的降解性能处于最佳状态.

Effect of Influent pH on Biodegradation Behavior in Dye Wastewater Treatment by Anaerobic-aerobic Membrane Bioreactor

The dyeing wastewater discharge has been characterized with relatively great fluctuation of pH value,which strongly affect the biodegradation ability of activated sludge in treatment plant.In this work,the behaviors of decolorization and organic compound degradation in a combined anaerobic-aerobic MBR process under the different influent pH value were investigated.The results show that decolorization efficiency is higher in aerobic zone than that in anaerobic zone when influent pH is in the range of 5.0 to ~8.0 ,but in reverse when influent pH is at 9.0.In addition,high decolorization efficiency is easily achieved at alkaline influent in the whole system.In anaerobic zone,low COD removal efficiency is observed and almost independent on influent pH.By contrast,in aerobic zone,relatively high COD removal efficiency is obtained and neutral-acidic influent seems more favorable to COD degrading bacteria than alkaline influent.When influent pH is 8.0 and 9.0,the increase in COD removal efficiency of the whole system is mainly contributed to effectively soluble COD removal by membrane.Consequently,it is found that the strong buffer effectiveness caused by anaerobic degradation plays a important role in guaranteeing the pH range in which favor to the anaerobic and aerobic decolorizing bacteria.