Study On The Evaluation And Reatment Echnology Of Black And Odorous Waters In Urban Area Of Chaohu

This paper takes the typical black and odor water in Chaohu City as the research object,and selects CODCr,BOD5,NH3-N,TP and DO as the key indicators for evaluation of black and odor in the water,combined with river surface pollution assessment method,single factor water quality index index method and comprehensive water quality.The index index method was used to construct a prediction and prediction system for water and foul smell in urban areas of Chaohu City.The comprehensive evaluation of heavy metal pollution in water bodies was conducted based on the method of cumulative index,potential ecological risk index and pollution load index.The research content and main conclusions are as follows:(1)This study classifies the apparent characteristics of the water into four grades: light yellow,odorless,light gray,slight black,black,and dark black,and the corresponding black water divided into four grades: black and odorless,light black and odor,moderate black and odor,and heavy black and odor.Combining the water quality index with the actual sensory judgement results,we obtained: DO = 3 mg/L,CODCr = 60 mg/L,NH3-N = 8 mg/L,TP = 0.8 mg/L,and BOD5 = 20.5 mg/L are the single-factor threshold value of black and odor appeared in the water of the urban area of Chaohu City;the integrated water quality index X1.X2=7 are the comprehensive index threshold of black odor in the water of Chaohu City.(2)This study used the water black odor prediction and evaluation system constructed to evaluate the black and odor of the water in Chaohu City.The study found that: the Tan wei xin cun reservoir and the Jia tang wei cross canal are full of heavy black and odor throughout the year,and the Dong pie hong ditch and An cheng wei trunk canal are stinking throughout the year,the middle ditch of the Century Avenue is full of youthful smell,and the Lu jia river has no black and odor throughout the year.Under the premise of no governance measures,the degree of black odor in the water is obviously lighter than that in the dry season.(3)In this study,combined with the geoaccumulation index method and the potential ecological risk index method,a comprehensive evaluation of the heavy metal pollution of the water body sediments results in: the main heavy metal pollutants in the six water bodies sediments are Cd and Hg,both of which contribute to the comprehensive ecological risk.As high as 83.22% to 90.17%,the overall ecological risk of Cd tends to be very strong,and the ecological risk of Hg is generally moderate.Combined with the pollution load index method and the potential ecological risk index method,a comprehensive evaluation of the heavy metal pollution of the water body sediments was obtained: the comprehensive pollution level of heavy metals in the sediment is all moderately polluted;the overall ecological risk level is Dong pie hong ditch> Lu jia river> An cheng wei trunk canal > Jia tang wei cross canal> Century avenue central ditch> Tan wei xin cun reservoir,where the first four sampling areas have a relatively high comprehensive ecological risk,and the latter two sampling areas have a moderate overall ecological risk.(4)This study can provide reference for comprehensive treatment of black and odor bodies in Chaohu city and similar areas.