Study On Chromaticity Removal Of Biochemical Tail Water In The Industrial Wastewater Treatment Plant

The discharge of industrial wastewater and domestic sewage accelerates the process of environmental pollution,in which chromaticity,as an important index of water pollution evaluation,becomes an important direction of sewage treatment research.The chromaticity of sewage is often related to the colored organic matter and non-ferrous metal ions,which not only affects human life in sensory sense,but also pollutes the environment seriously.Therefore,the treatment of wastewater chromaticity is an important work.In this study,the biochemical tail water of industrial wastewater treatment plant was studied.Firstly,3DEEM,FT-IR and GC/MS mass spectrometry were used to characterize the biochemical tail water,and Fe,Mn and humin acid in the biochemical tail water were further determined.The concentration of metal ions and humic acid were studied and analyzed,and the source of chromaticity pollution was inferred.Then the coagulation sedimentation activated carbon adsorption process and ozone oxidation process were used to treat the biochemical tail water.The influence of various factors on the treatment effect was studied and the best treatment process was determined.The main conclusions of this study are as follows:?1?The determination of the concentration of Fe and Mn in biochemical tail water shows that the low concentration of Fe and Mn is not the main cause of chroma of biochemical tail water.?2?According to the analysis of 3DEEM,humic acid is the main substance causing the chromaticity of biochemical tail water,and the humic acid may mainly come from A enterprise.The content of humic acid in biochemical tail water determined by spectrophotometry was 41.360 mg/L.The biochemical tail water was studied by FT-IR.The same functional group was found in the biochemical tail water and the effluent from A enterprise.The content of Fe and Mn in biochemical tail water was determined by phenanthroline spectrophotometric method and potassium periodate oxidation photometric method,respectively.Compared with the color of Fe and Mn standard solution,their color in biochemical tail water was found to be very low.The main reason for the color of Fe and Mn is not biochemical tail water.?3?The complexation experiment of humic acid and Fe shows that the higher the concentration of Fe is,the higher the concentration of complex is.But after aeration,the higher the concentration of Fe,the smaller the chromaticity of the reaction solution after aeration.?4?Coagulation-sedimentation activated carbon adsorption process was adopted to treat the biochemical tail water.When the removal rate of CODcr was 29.2%,the PAM concentration was determined at 1mg/L.When the optimal PAC concentration was 20mg/L,the removal rates of CODcr and chromaticity were 33.3%and 63%,respectively.When the optimal amount of activated carbon was 0.3g/L,the removal rates of CODcr and chromaticity were 26.7%and 60.7%,respectively.The chroma removal rate of 71.4%was determined as the optimal adsorption time of activated carbon for 25 minutes.?5?The ozonation process was used to treat the biochemical tailing water,and the research on the removal of chromaticity in the ozonation time was carried out.At the beginning,the chromaticity of the tailing water increased due to the oxidation of Fe²⁺into Fe³⁺and then decreased until it reached a stable state.At this time,when the removal rates of CODcr and chromaticity were 18%and 46%respectively,the ozonation time was determined to be 7 minutes.In the study on the removal of chromaticity by ozone concentration,the higher the ozone concentration added,the lower the chromaticity will be.At this time,when the chromaticity removal rate is 75%,the ozone concentration is determined to be 3.048mg/L.This study analyzed the biochemical tailwater of industrial wastewater treatment plant through characterization method,and determined that the main color substance causing the biochemical tailwater was humic acid.And humic acid may be mainly from A enterprise.Through the comparison between the two processes,it can be seen that the cost of ozone oxidation process is high,while the coagulation sedimentation activated carbon adsorption process has the advantages of low cost.Considering the efficiency and cost of chromaticity removal,coagulation-sedimentation activated carbon adsorption process was determined as the best process.