Classification And Characterization Of Dissolved Organic Matter In Secondary Effluent Of Wastewater Treatment Plant And Its Characteristics Of Ozonation

Owing to dissolved organic matter(DOM) has complex structure and various types, it was one of the main remove targets of sewage treatment. According to this problem,based on the principle which ozone could change the structure of the organic matter, study took aim of the dissolved organic matter in two stages of a wastewater treatment plant.Dissolved organic matter was divided into six components by resin grade analysis, Hydrophobic base(HOB), Hydrophobic acid(HOA), Hydrophobic neutral(HON), Hydrophilic base(HIB), Hydrophilic acid(HIA), and Hydrophilic neutral(HIN). The study discussed the change rule of each composition before and after ozonation, and studied the effect of ozonation to dissolved organic matter of the secondary effluent.The research results showed that the hydrophobic substances were the main part of the secondary effluent dissolved organic matter, accounted for 70%.The HOA TOC accounted for 39% of the raw water, UV254 accounted for 51%; HON TOC accounted for 38% of the raw water, UV254 accounted for 30%. According to the three dimensional fluorescence spectrum analysis could be seen that in the secondary effluent, humic substance fluorescence intensity of HOA and HON were larger and the hydrophilic components of protein peak fluorescence intensity were bigger. X-ray photoelectron spectroscopy analysis indicated that the HOA, HON contained more aromatic compounds, while the HOB contained more carbonyl and carboxyl functional groups.After ozonation, ozone could significantly improve the secondary effluent of sensory indexes, such as removing the chroma could reach 75%.Besides ozone could react with the organic reaction of the structure of unsaturated change organic molecular structure and properties, and could make three-dimensional fluorescence intensity of the secondary effluent dissolved organics decreased obviously. When ozone dosage was 0.45 mgO3 / mgTOC, HON TOC decreased and the hydrophilic components TOC rised up more. It means that HON turned into hydrophilic components after ozonation at this ozone dosage. According to the experimental results of XPS, it could been shown at this ozone dosage, ozone will react with benzene ring first, destroy its conjugate structure, increase the fat content of organic matter.When ozone dosage continues to increase, it could be concluded that ozone and the reaction order of soluble organic matter is: HON>HOA>HOB, then ozone could react with hydrophilic components. Molecular weight distribution of the results showed that ozone had no effect on the molecular weight distribution in humic substances, but it would react with small molecule protein material priority. At the 0.98 mgO3 / mgTOC ozone dosage, ozone could react completely with the hydrophilic and hydrophobic components. Besides when ozone dosage was increasing, dissolved organic matter in the proportion of oxygen containing functional group(carbonyl and carboxyl) was increased.Above all, ozonation could change the chemical structures and properties of dissolved organic matter in the secondary effluent. It provided theory basis for the choice of technology, improved the efficiency of the urban sewage secondary effluent treatment.