Effects Of Sediment Pollution And Applied Study On The In-Situ Remediation Of Sediment By Immobilized Microbe Technology

In view of the problem of secondary pollution caused by the release of pollutants from contaminated sediment.In this thesis,the present situation of sediment pollution and the influence of contaminated sediment on overlying water were studied.Then,the characteristics of immobilized microbe carriers were analyzed.The optimum conditions of immobilized microbe in in-situ sedimentation remediation was screened out by changing the installation position of the device,the overlying water DO and the pH.Finally,the microbial community structure of the immobilized microbe in-situ repair of sediment system was analyzed by high-throughput sequencing technique under the best experimental conditions.The results of this study are of great significance to optimize the operation of the reactor and improve the treatment effect.It can provide reference for the practical application of immobilized microbe technology in repairing the sediment in the lake.(1)The results of the evaluation of the sediment and water bodies in the lake showed that the pollution degree of phosphorus,nitrogen and carbon in the lake sediments belonged to severe pollution,and all the water body has reached the eutrophication,in addition,the correlation between the pollution degree of the lake water body and the pollution degree of the sediment is positively correlated.(2)The maximum amount of sediment release can make the overlying water from deionized water into inferior V water according to the surface water environment quality standard(GB3838-2002).When the pH is neutral and aerobic conditions,can reduce the release of sediment pollutants.(3)The average pore size was 3.4 nm,the total pore volume was 0.03 cm3/g,and the specific surface area was 31.7 m2/g,calculated by BET and BJH models.The results of scanning electron microscopy(SEM)show that there are various structures such as immobilized microbial carriers,which are conducive to the growth and reproduction of microbes and the increase of microbial concentration.The results of energy spectrum analysis showed that the main components of immobilized microbial carriers were SiO2.(4)The optimum conditions of in-situ remediation of sediment by immobilized microbe were as follows:the optimal position of the carrier column is muddy water interface,the best DO is 6 mg/L,and the optimum pH is 7.Under the best conditions,the polluted raw water,classified as inferior Class-?upgraded to Class-III in 30-days remediation with TOM,TN and TP removal rates of 33.4%,43.4%and 23.2%,respectively.In contract,the control group without the assistant of aerated immobilized microbe still remains at inferior Class-?.The concentration of organic matter contained in the mud is greatly reduced,and even five kinds have been disappeared,but there is also produced a new one.(5)High-throughput sequencing analysis reveals that immobilized microbe technology could improve the species diversity and abundance of the flora,and enhance the similarity between the sediment and the overlying water in the system.The dominant bacteria of the overlying water were Perlucidibaca,Limnohabitans,Bacillus,Hydrogenophaga,Mycobacterium etc.And the dominant bacteria of the sediment were Methanolinea,Methanoregula,Candidatus Competibacter,Methanosaeta etc.Total phosphorous,certified by the redundancy analysis,is the key environmental factor of microbial community structure in both overlying water and sediment.