Optimization Of Advanced Treatment Process Of Ozone Biological Activated Carbon Based On Water Sources In The Lower Reaches Of Yangtze River

The unsteady factors of water quality in the Yangtze River Basin have been increased recent years,the deterioration of river water quality results in the increase of precursors of disinfection by-products and the instability of water quality in the network.Therefore,it is necessary to optimize the water treatment process to reduce the generation of disinfection by-products and guarantee the safety of drinking water quality.According to the characteristics of raw water quality in Zhenjiang Zhengrunzhou,and the pilot plant optimization of pre-ozone process-conventional treatment process-O₃-BAC process was studied,then present the suitable technological parameter to make high quality water.The main results are as follows.In general,Zhenjiang Zhengrunzhou has a good source water quality,which basically meets the Class II standards in"Environmental quality standards for surface water"?GB 3838-2002?,and partially meets the Class I standards on a monthly basis with certain seasonal variations.After the implementation of source water quality safeguard project,the source water quality has improved.The small molecular precursor dominates the organic matter in the source water of Zhengrunzhou,which is mainly distributed in the<3kDa.The strong hydrophobic composition counts the highest proportion.The conventional treatment process has limited removal of small molecular organics,while whey can be effectively removed in the advanced treatment of O₃-BAC to reduce the risk of the disinfection by-products formation and improve water quality.The optimization research of pre-ozone process-conventional treatment process-O₃-BAC process was conducted using pilot plant.The results show that when the pre-ozone dosage is1.1mg/L,the pretreatment process has the best comprehensive treatment effect for each pollutant.While the significant increase of CH₂O and BDOC cannot guarantee the safety and biological stability of effluent,which needs further treatment process.When the PAC dosage is18mg/L,the overall treatment effect of each pollutant is best in the conventional treatment process,while it cannot guarantee the effluent biological stability.Besides,adding pre-ozone process before conventional process can promote the treatment effects,especially for the organic materials that are difficult to handle in this process.When the ozone dosage is 2.5mg/L,the removal efficiency of all pollutants is optimal in the advanced treatment process,the biological stability of the effluent is guaranteed,and the water quality indexes have basically met the high quality water standards.When the ratio of three-zone ozone injection is 3:1:1,the removal efficiency of the advanced treatment unit is higher than that of the single-point injection.Combined with the results of pilot test,the optimization research on advanced treatment demonstration project was studied relying on Zhenjiang Jinshan water treatment plant.One-year follow-up monitoring of the entire advanced treatment process in water plant was conducted with the optimization research of ozone dosage on advanced treatment unit.The experimental results were basically consistent with those of the pilot test.When the ozone dosage is 2.4mg/L,the advanced treatment unit has a better effect on the removal of pollutants:The turbidity of the effluent is lower than 0.2NTU,and the COD_Mn is lower than 1.1mg/L,the effluent BDOC is lower than 0.2mg/L,the biological stability of effluent is guaranteed,and all the monitoring indexes can satisfy the evaluation method of high quality water.The effect of the advanced treatment process is significantly better than that of the conventional treatment process.