Analysis Of Organic Matter Characteristics And Optimization Of Advanced Treatment Process For Drinking Water In Yancheng City

In recent years,with the deterioration of water quality,the advanced treatment process has been widely accepted by water plants as a key technology to solve water quality problems.Single water source water supply is difficult to meet the needs of urban water supply safety,but different water source water supply also has problems such as unstable water source quality,compound pollution,and the content,structure and characteristics of the organic matter produced by the disinfection by-product precursor?DBPsFP?are currently hot issues.Therefore,it is of great theoretical significance and practical value to explore the advanced processing parameters that match the water quality characteristics of the raw water in the multi-water source water supply mode.This topic firstly investigated the water quality of the water source and raw water in YanCheng City,the following aspects of research work were mainly carried out to reduce the concentration of organic matter,DBPsFP and ensure the biological stability of drinking water:?1?using“pre-ozone+conventional treatment+ozone-bio-activated carbon?O₃-BAC?advanced treatment+disinfection process”,focusing on the pre-ozone dosage,coagulantion?PAC?dosage,post-ozone dosage and disinfectanion?NaClO?dosage,providing reference for the operation and control of the drinking water advanced treatment demonstration project;?2?combined with the pilot test to investigate the treatment of raw water under different water supply conditions,clarified the necessity of switching water sources and the rationality of parameter optimization.The raw water is the mixed water of Beijing-Hangzhou Grand Canal and YanLong Lake.The mixing ratio is 2:1.The trial was conducted from June 2018 to March 2019,the precursors of disinfection by-products in raw water showing high summer content and low winter content.The total trihalomethane formation precursor?TTHMFP?varied from 290.14?g/L to 413.83?g/L,The total haloacetic acid formation precursor?THAAFP?ranged from301.43?g/L to 628.55?g/L,both THMsFP and HAAsFP mainly formed by the hydrophobic organic matter.When the ozone dosage was 0.7 mg/L,the removal rate of the strong hydrophobic organic substance and hydrophilic organic matter were 22%and 10%,respectively,and the removal rates of TTHMFP formed by weakly hydrophobic organic matter and neutral hydrophilic organic matter were 48.5%and 27.7%,the removal rates of THAAFP which composed by polar hydrophilic organic compounds and strong hydrophobic organic compounds were 29.1%and 25%,respectively.The AOC content in the effluent of the pre-ozone unit is usually higher than that of the raw water,and the removal rate of BDOC was only 9.7%.When the dosage of coagulant was 35 mg/L,the removal rates of TTHMFP and THAAFP composed by strong hydrophobic organic compounds were 55%and 46.9%,respectively,the removal rate of AOC and BDOC reached 25.5%and 32.5%,continue to increase the dosage of coagulant,the removal rate increased by less than 6%.When the post-ozone dosage was 2 mg/L,the removal rate of polar hydrophilic organic substance and neutral hydrophilic organic substance by BAC unit was 40.3%and 58.9%,the removal rate of TTHMFP generated by hydrophobic organic substance was 59.9%,and the removal effect on HAAsFP was inferior.The BAC unit mainly removed DBPsFP formed by hydrophilic organic matter.The removal rates of THAAFP and TTHMFP by BAC unit were 53.8%and 78.3%,respectively.The removal rate of TTHMFP and THAAFP by O₃-BAC unit were 73.2%and58.9%,respectively.Due to the BAC unit,the removal rate of the AOC and BDOC by the BAC unit were 64%and 78.6%,respectively.The hydrophobic component is the main reaction component of the sodium hypochlorite disinfection reaction.When the dosage of the disinfectant was 0.6 mg/L,strong hydrophobic component is reduced by 45.8%,hydrophobic component was reduced by 47.6%,neutral hydrophilic component and polar hydrophilic component were increased.When the dosage of ozone was 0.6 mg/L,the removal rate of THHMFP and THAAFP were 30.6%and 26.9%.The contents of AOC and BDOC in the disinfected effluent were 138.2?g/L and 0.229 mg/L.The raw water quality under the combined water supply of Yanlong Lake and Beijing-Hangzhou Grand Canal is better than that of the raw water after the joint water supply of YanLong Lake and TongYu River.The removal rate of TTHMFP,THAAFP and BDOC in the whole process of YanLong Lake and TongYu River combined water supply were 39.7%,34.9%and 77.5%,respectively,and the BDOC content of disinfection effluent was 0.229mg/L.The removal rate of TTHMFP,THAAFP and BDOC were determined by the water treatment process of YanLong Lake and Beijing-Hangzhou Grand Canal combined water supply were 46.6%,40.3%and 84.8%,respectively,and the BDOC is stable below 0.2 mg/L.This study showed that when the pre-ozone dosage was 0.7 mg/L,PAC dosage was 35mg/L,the post-ozone dosage was 2 mg/L and the disinfectant dosage was 0.6 mg/L,the advanced treatment has significant removal effect on each pollutant,which can guarantee the safety and biological stability of effluent water quality.The optimized operation results provide the theoretical basis and technical support for the water quality purification of water quality in the actual operation of the water plant,which is of great practical significance for ensuring the safety of drinking water for residents.