Enhanced In-Situ Bacteria Inoculation Technology By Lifting Water And Aeration For Micro-polluted Raw Water Restoration

Lakes and reservoirs have become the main source of drinking water in northernarea in recent years, as the pollution problem of lakes and reservoirs becameincreasingly prominent, the water quality safety is subjected to extensive attention. Asthe micro-polluted source water is oligotrophic, low temperature and aerobic, whichmakes the restoration very difficult. In order to solve this problem, this study combinedthe in-situ inoculation technology and lifting water and aeration technology, studied thenitrogen removing characteristic of oligotrophic bacterium at low temperature andaerobic conditions.The nitrogen removal effect of oligotrophic aerobic bacterium at low temperaturecondition was studied here. This paper utilized the in-situ inoculation technology toresearch its remediation effect for the micro polluted water. In addion, this studyanalyzed the suspension characteristics of the bacterium by counting the bacteriacontent at different height of the reactor, to ensure that the in-situ inoculationtechnology and lifting water and aeration mixing technology could be combinedwell,which can make the denitrifiers work effectly.In order to solve the nitrogen and organic pollution problem of source waterreservoir effectively, by dosing oligotrophic aerobic denitrifiers, the effects of in-situinoculation technology for micro-polluted source water restoration was studied underthe pilot scale. The test result shows that, at the inoculating dose of bacteria is0.1 mg·L^-1, DO mass concentration is5.0⁸.0mg·L^-1, and the water temperature is16²5℃, the removal effect of the major pollutants in water system of NO₃^--N, TN andCOD_Mnis good, mass concentration of which has been reduced from1.68mg·L^-1,2.25mg·L^-1and5.50mg·L^-1to minimum value0.75mg·L^-1,0.95mg·L^-1and3.03mg·L^-1,and the maximum removal rate can reach at57.5%,57.7%and44.9%, respectively. Theremoval effect of nitrogen and organics can meet the standard of class â…¢ of "Environmental quality standards for surface water", which proves that in-situ bacteriainoculation technology applied in the quality improvement of micro-polluted sourcewater is feasible.The function mechanism of oligotrophic aerobic denitrifiers was alsodiscussed in this paper.Finally, the study also analyzed the microbial community structure. Here discussedthe diversity of the bacteria communities, and analyzed the characteristic of the mainbacterium and the differences between the water samples at different aeras and depth,which all could provide enough theoretical support for the engineering projectapplication of the in-situ inoculation technology.