Characterization Of Dissolved Organic Matter In The Metabolic System Of The Urban Water

Dissolved organic matter widely exists in the metabolic system of the urban water. It easily reacts with chlorine and produces disinfection by-products in the source water and the secondary effluent. The dissolved organic matter in the receiving water can be combined with metal ions and organic pollutants, such as polycyclic aromatic hydrocarbons, polychlorinated biphenyls and pesticides. It has a significant impact on their migration transformation, toxicity and bioavailability. The total amount and chemical properties of DOM in the metabolic system of the water are studied. The changes of ultraviolet, infrared, fluorescence characteristics and molecular weight of DOM are explored. The infrared, fluorescence characteristics and molecular weight of humus are studied, which is a typical DOM.It showes that the concentration of DOM in the source water is the lowest.And the aromaticity is the highest. The molecular weight is also the highest between 1 kDa~10 kDa. And also there is C=C stretching vibration of mononuclear aromatics. The concentration of DOM in the municipal wastewater is 13 over the source water. The aromaticity is lower by 73%. Most of the aromatic compounds with C=C and C=O comes from human activities. A few are derived from the source water after treatment. The concentration of DOM in the secondary effluent is lower by 84% after treatment. As affected by effluent, the concentration and aromaticity of DOM in the receiving water is similar to the secondary effluent. While as surface water, there is C=C stretching vibration of mononuclear aromatics in the receiving water.The paper uses the XAD-8 resin to extract humus and uses chemical analysis method to characterize the humus. The technique of the 3DEEM and analytical method of FRI are used in the qualitative and quantitative analysis of the fluorescence substance. Humus is included there.It showes that humus in all the water has similarity and difference. The difference shows that humus in the fluorescence substance is the most, accounting for 67%.The content of humus reduces significantly in the municipal wastewater, accounting for 24%.The humus in the secondary effluent accounts for 44%, becoming the main fluorescence substances in the DOM. The humus in the receiving water accounts for 39%.The similarity shows that humus has benzene ring, carboxyl and phenolic hydroxyl group. It also has fluorescence peak of fulvic acid and humic acid. Among the humus, fulvic acid is the most.The sewage treatment course is studied, which plays a major role in the metabolic system. It showes that the concentration of the DOM along the treatment process gradually reduces. The total removal rate was 84%. The efficiency of anaerobic microbial treatment is the highest, which has a 58% percent. The aromaticity rises step by step. The efficiency of anaerobic microbial treatment is the highest, which has a 96% percent. Among the humus, fluorescence substance in the II region is the most, reducing gradually along the treatment process.The removal rate in anaerobic stage is 74%. The removal rate in aerobic stage is 27%.Fulvic acid is the fourth fluorescence substance.It becomes the second largest category of substances starting from the end of the anaerobic tank. The relative content in the inflow is 17%. While in the effluent it is up to 26%. Its removal rate in anaerobic stage is 54%. The removal rate in aerobic stage is 23%.