Study On Biological Reduction Of Organic Pollutant In River Sediments By Increasing Oxygen

Sediment pollution is one of the important urban rivers pollution research contents, and also is a prominent environment problem worldwide. Because of costliness and destroying ecosystem environment, the ex-situ remediation technology of contaminated sediments is restricted in application, therefore the in-siu remediation technology is becoming interested. Study on biological reduction of organic pollutant in river sediments by increasing oxygen has important application value.The Shenzhen Buji River sediment was studied by artificial oxygen-increasing technology aid of bacterial augmentation on sediment reduction of organic pollutant in static small pilot study. The study includes:Firstly, the physical and chemical indicators of sediment was analysed and the results show the sediment was slightly alkaline, in a reducing environment, high organic pollutant content that reaches 157.1g/kg , and seriously organic pollution. In the sediment aeration experiment in the condition of mixing fully of water and sediment, the ultimate removal rate of organic pollutants within 30 days is measured. Experimental results show the organic pollutant content decreased 34.3% within 30 days ultimately.And then following the in-situ remediation technology requirements of sediments that it does not affect the overlying water body, two oxygen-increasing approaches that slightly perturbed the sediment were selected: the pure oxygen aeration and oxygenated water injection. The change of organic pollutant content was mearured in the biological reduction experiment of organic pollutant in sediment within 105 days. The results show that: through the pure oxygen aeration treatment, organic pollutant content in sediment decreased by 17.0%; by the oxygenated water injection treatment, organic pollutant content in sediment decreased by 22.3%. And a mathematical model was built to analyze the degradation of organic pollutant in sediment.Based on 105 days sediment treated by pure oxygen aeration and oxygenated water injection, special bacteria was added to continue sediment organic pollutant reduction. The organic pollutant content change in sediment was measured in 32 days, and the results show that by pure oxygen aeration aid of adding bacterial treatment, organic pollutant content was further decreased by 4.2%, and the removal rate of organic pollutants increased 1.9% compared to pure oxygen aeration; by oxygenated water injection aid of adding bacteria treatment, organic pollutant content was further decreased by 5.9%, and he removal rate of organic pollutants increased 2.4% compared to oxygenated water injection. The experimental results show that bacterial augmentation plays a more significant role in degrading hardly-biodegradable organic pollutant.Finally, PCR-DGGE technology was used to analyze the total number of sediment bacteria and bacterial diversity, and the result shows that after treatment by the pure oxygen aeration and oxygenated water injection analysis respectively, the number of sediment bacteria and bacterial species have a significant increase.