A Comparative Study On The Nitrite Removal Efficiency Of Different Oxidation Processes

In order to solve the problem of high nitrite content in the effluent of the second water plant in Yantai Development area,the research analyzed the source of nitrite in the water plant,investigated the effectiveness of different oxidation processes to remove nitrite,and analyzed the different types of oxidants and their respective The effects of factors such as the dosage of oxidants,p H,oxidation time,temperature and ammonia nitrogen concentration,and COD on the removal efficiency of nitrite,this paper investigates the hazards,current status and treatment of nitrite pollution in drinking water plants at home and abroad through literature data Comprehensively understand the methods and other aspects,and then take the second water plant in Yantai Development area as the research object,and verify the nitrite concentration,NO₃^--N concentration,ammonia nitrogen concentration and residual chlorine concentration in the tap water provided by the water plant through design experiments Determination.In order to reduce the concentration of nitrite in tap water,by studying the dosage of different types of oxidants on the removal effect of nitrite,the optimal oxidant dosage scheme was finally determined.The experimental results showed that the optimal dosage of chlorine was 6mg/L.The optimal dosage of other oxidants is 2～3mg/L.The research results have certain theoretical and data support for the removal of nitrite during the actual operation of the water plant.The plant formulates nitrite removal has great reference significance,the research results are as follows:（1）It is confirmed that the concentration of nitrite in the raw water of a water plant is at a low level through experiments.Therefore,the nitrite in a water plant is mainly caused by the consumption of liquid chlorine in the oxidant during a long-distance process,which makes the concentration of residual chlorine at the end of the pipeline insufficient,so that the removal of nitrite in the tap water is not complete.（2）The best dosage of chlorine is 6mg/L,and the best dosage of other oxidants is 2～3mg/L.（3）The suitable growth temperature of nitrous bacteria is 10-37℃.When the water temperature is 20-30℃,the nitrite nitrogen formed by nitrous reaction can be completely oxidized to nitrate nitrogen.When the temperature is lower than 20℃or higher than 30℃,the accumulation of nitrite in water will occur.（4）The p H value of tap water is 7.54～8.48,which is beneficial to the accumulation of nitrite nitrogen.（5）With the increase of oxidation time,the removal rate of nitrite nitrogen by oxidants increased to a certain extent,of which the removal rate of potassium permanganate increased significantly,and the removal rate of nitrite nitrogen increased by 4%compared with that of 0.5H in 1H;the removal rate of chlorine and chlorine dioxide increased little with the oxidation time,because the two oxidants reacted rapidly in water at the beginning of 0.5h It can oxidize most of the nitrite nitrogen in water.It is known from the analysis of the above test results that the high nitrite content in the effluent of the second water plant in Yantai Development area mainly exists in the pipe network,because the residual chlorine concentration in the pipe network water is insufficient and the current disinfection process is not effective in removing nitrite Ideally,consider the combined process of chlorine plus potassium permanganate,which not only has a better effect than the single use of chlorine as a disinfectant to remove nitrite nitrogen,but also greatly reduces disinfection by-products and improves the taste of tap water.The proper temperature,PH and reaction time of oxidant to remove nitrite were analyzed.