Researches On The Enhancing Treatment Technology For A Sewage Plant Mainly Treating Dyeing Wastewater

Hong Xi Sewage Treatment Plant mainly accepts dyeing wastewater whose average CODcr is more than1000mg/L, accounting for nearly80%of the total flow. Though the desizing or alkali weight-reduction water and rinse water after desizing or alkali weight-reduction account for8.33%and55.6%of the dying water, they take up34.0%～50.1%and43.8%-46.7%of CODcrrespectively. The printing enterprises treat wastewater through "coagulating sedimentation+A/O" or airfioatation, but the CODcr of discharge water is over the standard. In summer or winter, the inflow of Hong Xi Sewage Treatment Plant has higher CODcr in5:00～11:00and higher flow in23:00-3:00. Relatively it has lower CODcr in11:00～17:00and lower flow in9:00～13:00. The peak of CODcr comes later than that of flow. Both of CODcr and flow are higher in night and lower in day. The flow and the change of flow in summer are larger than those in winter which causes higher hydraulic loading and organic loading in summer.Efficient hydrolysis reactor started after the aerobic active sludge was input in the reactor. The optimal working parameters of the reactor were the positive internal recycle flow direction,40m3/h of the internal recycle flow and0.3m3/h of the inflow. In this case, CODcr of the inflow decreased nearly40%. The aniline and naphthylamine might be produced in the process of decomposing dyeing wastewater which led to the higher NH3-N in effluent and inhibition for B/C. It was discovered by the ultraviolet and visible spectrophotometer that the organics which contain benzene ring, naphthalene nucleus, azo linkage, carbonyl and benzoic acid were decomposed. O3and O3-H2O2technologies had good decoloration effects whose removal rate reached74.5%, but they had little influence for CODcr removal rate. Microbubble process was better than micropore aeration process. O3-BAF, O3and O3-H2O2processes have a threshold for low concentration wastewater. MBR had a stable CODcr removal from250mg/L to65mg/L of the wastewater mixed with outflow of the primary settling tank and outflow of the final settling tank. Compared with other technologies, MBR working as an advanced treatment for Hong Xi Sewage Treatment Plant is most effective and stable. Efficient hydrolysis+MBR could replace the existing process in the sewage treatment plant.