Design And Operation Control Of Tanning Wastewater Treatment

In this paper,a tannery wastewater treatment plant tannery wastewater as the research object,according to China's wastewater treatment technology and tannery wastewater quality characteristics,through the first phase of the plant can not Stability and meet the corresponding status of emission standards,analysis of its construction and operation of the existing problems,through the technical route of the technical and economic compari-son,the final phase of a transformation and expansion of the technical route for the com-bination process for the main process design Aiming at the adjustment and control of the A/O bioreactor cell,the technical and economic analysis of the second-stage project was carried out for the regulating tank,pre-aeration tank unit,mixed reaction primary settling tank unit,hydrolytic acidification unit and A/O bioreactor unit.1)The main problems in the first phase of tannery are as follows:no homogeneous regulation of incoming water,flocculation system and acidification and hydrolysis system play a small role in the acidification and hydrolysis of refractory COD_cr.The degradation of COD_cr could cause nitrification in the biochemical system and the concentration of NH₃-N in the effluent water,which could inhibit the nitrification of the downstream inte-grated plant.2)According to the problems existing in the construction and operation of the first phase of the tannery,the pre-treatment process?pretreatment?coarse grill,fine grill,aera-tion grit?+pretreatment process Coagulation and sedimentation+anaerobic hydrolysis and acidification?+two-stage A/O biological treatment",the main process unit in the process system was designed to determine the design parameters of the relevant process unit and the corresponding structure size;3)The start-up and stable operation of the A/O bioreactor cell is divided into the start-up stage and the stable operation stage.The experiment is carried out by laboratory test.Coagulation unit of the best pharmaceutical and dosage,through the sludge inocula-tion biochemical system commissioning start mode,the latter part of the gradual adjust-ment of water and water load,and timely manner to add nutrients to the biochemical sys-tem unit optimal control conditions The water quality of the effluent can be controlled at the level of COD_cr?1 800 mg/L,BOD₅?700 mg/L,NH₃-N?250 mg/L,and the effluent water quality can reach the stable operation state.The COD_cr?120mg/L,BOD₅?30mg/L,NH₃-N?35mg/L,which meet the design requirements,can meet the requirements of dis-charge standards;4)From the results of the commissioning and operation of the project,it can be seen that the first phase of reconstruction of the process line and the second phase of the recon-struction project are reasonable and the pertinence of each treatment unit is strong,which is the"combination of biological method,The processing links are closely linked,com-plementary advantages,stable and reliable operation.The total investment for renovation and expansion project is 9 561 million yuan,and the unit operating cost of tannery is 1.82yuan/m³,which belongs to medium level in the industry.The total removal of pollutants such as COD_cr and NH₃-N were 33 290 t/a and 3 540 t/a,respectively,and the social and environmental economic benefits were significant.