关于炼油污水膜法推流式生化装置运行方式的几点思考

Thoughts on Operation Mode of Membrane Plug-flow Bioreactor for Refinery Wastewater Treatment

生化装置处理能力的实现与装置的运行方式有着密切关系。膜法推流式生化装置是炼油污水处理场常用的一大类生化处理设施,具有一定的代表性。新近发布的标准对外排污水的总氮提出较为严格的要求,在膜法推流式生化装置中,膜法A/O装置作为反硝化主要设施重新受到重视。但是现模式膜法A/O装置的反硝化效果不理想,可以延长反硝化段的停留时间并脱除回流水中的溶解氧,为反硝化创造有利条件。在膜法推流式生化装置以硝化方式运行的情况下,大回流必然影响到装置的处理效果,而减小回流量对装置的处理能力是有增强作用的,同时可以节省回流泵运行能耗。如果只作为过程处理设施,后续还有其他生化装置保证达标处理,采用多点进水方式能够最大程度地发挥膜法推流式生化装置的处理能力。当遇到高浓度污水冲击时,闷曝并不是有效的处理方法,尽快用低浓度污水置换装置内的高浓度污水,使装置内微生物尽快恢复活性后再逐步提高进水负荷,才是正确的处理方式。

The processing capacity of bioreactor is closely related to its operation mode.Membrane plug-flow bioreactor,which is commonly used in refinery wastewater treatment plant,is a representative biochemical treat- ment facility.The newly issued standard poses more stringent requirements for the total nitrogen in wastewater discharged.In membrane plug-flow bioreactor,membrane A/O unit attracted much attention again as the main denitrification facility.However,the denitrification effect of the A/O membrane unit is not satisfactory under the current mode.Prolonging the residence time in denitrification section and removing dissolved oxygen from backflow water can create favorable conditions for denitrification.When the membrane plug-flow bioreactor is operated in nitrification mode,high backflow rate inevitably affects the treatment effect of the unit.Reducing the backflow rate can improve the processing capacity of the unit and reduce the energy consumption of re- flux pump.If the unit is only used as a procedural treatment facility and followed by some other biochemical units to meet the discharge standards,using multi-point influent mode can maximize the processing capacity of membrane plug-flow bioreactor.Aeration is not an effective treatment method when subjected to the impact of high concentration wastewater,replacing the high concentration wastewater in unit with low concentration wastewater as soon as possible to recover the activity of microorganisms in unit and then gradually increasing the influent loading is the right way.