Sludge concentration is one of the important parameters for membrane bioreactor(MBR).It influences the removal efficiency of the reactor.This paper investigates the increasing rule of sludge concentration by shortening hydraulic retention time(HRT) and increasing sludge retention time(SRT)

investigates the changes of CODCr in the influent and the effluent under the different sludge concentration

and investigates the influences of volumetric loading and sludge loading on the treatment effects of CODCr.The result shows that the concentration of sludge with mixed liquor suspened solid(MLSS) feature is increased with the decrease of HRT and the increase of SRT

but the sludge activity is evaluated at the same time.The sludge yield coefficient is reduced with the increase of SRT.The volumetric loading is increased with the decrease of HRT.The removal rate of CODCr keeps over 90%

which indicates that the MBR has favorable ability of shock loading resistance.