| The alkali-minimization wastewater is produced in the process of polishing crude terylene, which is characterized with high COD concentration, high alkalinity, high concentration of Terephthalic Acid (TA) and sharp change of wastewater quality and quantity. It is the main course of the effluent of alkali-minimization dying wastewater treatment plant failing to meet the discharge standard. There is still no effective treatment to clean this kind of wastewater. Membrane bio-reactor(MBR) combines the advantages of biological and membrane technology. High efficiency of removing pollutants, less excess sludge production and stable effluent are got from this technology. However, membrane fouling problem is main obstacle of development of this technology.This paper is based on the high concentration of TA and the advantages of MBR. The TA in the wastewater is recovered by neutralization method firstly, and the wastewater is treated by "Hydrolytic Acidification(HA) + hybrid MBR(HMBR)" process. Meanwhile, the contribution of particle packing to decrease the membrane fouling is researched.The orthogonal test is applied in the process of recovery TA by neutralization.Acid concentration, agitation speed and flow rate of feeding acid are selected as influencing factors to the size of recovered product. The result show that acid concentration is most important factor, agitation speed and the flow rate of feeding acid are following. The primary analyse of economical and social benefit of TA recovery is made.To research the influence of Ethylene Glycol(EG) to the bio-degrading of TA, the kinetics is applied to analyze the results of agitating flask experiments. The analyse results show that the presence of EG can restrain the bio-degrading of TA. The bio-degrading ratio of TA decrease with the concentration of EG increasing. The result is the theoretical base of the "HA + HMBR" process.The efficiency of "HA+HMBR" to treat the neutralization wastewater is stressed in this paper. The results shows that the total COD removal efficiency of the system is 95%. The range of effluent COD is between 24.6 mg-L"1 and 65.03mg-L*1, the average is 52.24 mg-L'1. The removal efficiency of TA is over 94%. The system is show great flexibility to loading changing. The COD removal efficiency decreases slightly when loading changing is made and the system return to normal after 2~3 days.The bio-degrading of EG and TA in Hydrolytic Acidification tank is researched in this paper. The results show that the EG can bebio-degraded effectively in Hydrolytic Acidification tank, but removal efficiency of TA is very low. The COD concentration in hybrid MBR is slightly lower than which in traditional submerged MBR. The membrane itself can intensify the treatment effect, the mechanism of which is analyzed. Meanwhile, the influence of HRE decrease to the system is researched.The variation of MLSS,MLVSS,VSS/SS in HMBR with time is researched. The reason of stable sludge concentration at 12000-13000 mg-L"1 is analyzed. Sludge theoretical production coefficient Yg =0.159 (kgVSS/kgACOD) and degrading coefficient b=0.023(d'1) is derived from results of the experiment.? These observations revealed that particle packing played an important role in improving the filtration performance of HMBR.The results indicated that the cake resistance of HMBR decreased by 86% and the critical flux of HMBR increased by 20% in comparison with traditional submerged MBR. During the long-term experiments, the increase rate of suction pressure for MBR was almost 3.3 times of that for MBR. These observations revealed that particle packing played an important role in improving the filtration performance of HMBR.
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