Study On The Treatment Of Perochemical Wastewater By Excess Sludge Reduced Membrane Reactor

The MBR process is used to treat TA and COD in waste water of petrochemical plants. This paper is mainly about the relationships of sludge with other parameters in MBR by researching the changing pattern of COD removal efficiency and TA degradation.The result shows that the sludge production is effectively reduced when ciliate is flourishing, at which time the sludge yield coefficient is reduced from 0.36 kgMLSS/kgCOD to 0.21 kgMLSS/kgCOD. On the other hand, from the appearance of vorticella to the appearance of rotifer, the sludge yield coefficient is not changed tremendously, but the quality of the effluent is improved. When the activated sludge is in the logarithmic growth phase with sufficient nutrient elements, the sludge yield coefficient is 0.37 kgMLSS/kgCOD. On the contrary, when the activated sludge is in the logarithmic growth phase with nutrient deficiency, the sludge yield coefficient is reduced to 0.13 kgMLSS/kgCOD and the quality of the effluent is getting worse. When the activated sludge is in the logarithmic growth phase with sufficient nutrient elements, the sludge yield coefficient has no relationship with the nutrient and in this stage, the sludge yield coefficient can be expressed by the following formula:(?)When the quality and quantity of influent is stable, the TA removal-efficiency bacterium get the advantages of flourishing, and the middle degraded substances make the COD concentration get higher, but these substances can be easily degraded by bacterium.The result shows that the sludge yield coefficient can be reduced to 0.05 kgMLSS/kgCOD from 0.29 kgMLSS/kgCOD when the sludge concentration increases from 6.2 g/L to 8.0 g/L. And in this condition, the sludge yield, the cost of sludge treatment and the quality of effluent are all improved.This research provides the technical support for the application of MBR in petrochemical companies.