Study On ASBR-MBR Process For Treatment And Reuse Of Pirnting And Dying Wastewater

Printing and dying industry is a main drainage department in our country,whose wastewater has great capacity,high level color and complicated components.Dye discharged into the water can reduce the diaphaneity,destroy the ecosystem and cause the cancer.Due to its harm to environment and human body,more and more attentions are paid to its treatment.The treatment of printing and dyeing wastewater has become one of the most important researches in the field of environmetal protection.The membrane bioreactor(MBR),which combines technology of the biological treatment and membrane separation,is a new technology for wastewater treatment and reuse,and has a promising application future for the treatment of persistent organic wastewater. Its removal effect of the organic and inorganic contaminants,influence of sludge concentration and flow of aeration and HRT,characteristics of biological phase and the decline and restoring of membrane flux were investigated through treating the wastewater from Mei Jing Xing Ye printing Ltd in Xinhui District,Jiangmen City, Guangdong Province in this dissertation.Experimental results showed:The experiment had been divided three stages.In the first,second stage,the experiment research in the treatment of printing wastewater adopt ASBR-MBR and MBR,which F/M was 0.21～0.26 kgCOD/(m³Â·d) in MBR and was all the F/M in ASBR-MBR,the removal efficiency of COD was over 45%and 65%,the effluent could meet the recycling waster standard for Mei jing Xingye printing Ltd.The conclusions were drawn through the contrast tests that in the removal effect of color,iron,hardness,ASBR-MBR was better than MBR;ASBR-MBR could achieve the desired goal of treatment in the short HRT,high volume load and low sludge load;In addition,ASBR-MBR was below MBR in the declining of membrane flux.Therefore, ASBR-MBR was confirmed optimal technology.In the third stage,the experiment research in the treatment of printing raw wastewater adopt MBR.In the stable operation of the system,the removal rate of COD remained 92.0%～94.2%and pH,COD_Cr,color indicators of the effluent were better than the national standard of the second time for the wastewater discharge limits(DB4426-2001) of the Guangdong Province.The experiment research in the treatment of printing raw wastewater adopt MBR was feasible.When the biological had many insects and rotifers in the stable operation of the system,the effect of treatment was the best,but the biological body of the first,second stage was smaller than biological body of the third stage,which may was the biological characteristic in the treatment of the low concentration printing wastewater.When the biological had a little insects and rotifers or not,the treatment effect was also good.The declining of membrane flux increased with the accretion of concentration of sludge.The pretreatment of ASBR could slower the course of declining of membrane flux and clearly improve the membrane's filtration capability.Aerating and backwashing helped restoring membrane flux.Chemical cleaning could thoroughly wipe off the contaminant on the membrane.