Applied Study On The Treatment Of Landfill Leachate By Immobilized Microorganism Technology

In view of the complex variability and recalcitrance of landfill leachate, immobilized microorganism was used for the leachate treatment in mis thesis to investigate the effects of hydraulic retention time (HRT), dissolved oxygen(DO) and influent pH on nitrogen removal, as well as the reasonable position of immobilized microorganism, analyses the degradation characteristics of the organic pollutants in landfill leachate by immobilized microorganism, and identifies dominant bacteria, finally makes a study of application demonstration, thus improves capacity of biological treatment, effectively solves the problems of efficient denitrification of landfill leachate, lighten the load of advanced treatment. The major results are as follows:(l)The specific surface area, pore volume and average pore diameter of carriers reached 31.744 m2g,0.028 cm3/g and 3.382 nm, respectively. The carriers’surface is loose and porous, it provides a suitable microenvironment for microorganism to growth and reproduction.(2)When immobilized microorganism treat anaerobic effluent, the optimalHRT is 72 h, DO is 5.0 mg/L, and influent pH is 7.5-8.5, as for aerobic effluent, the optimal HRT is 84 h, DO is 5.0 mg/L, and influent pH is 7.5-8.5. When treat anaerobic and aerobic effluent, the average ammonia removal rate arrived at 63.8% and 92.6%, respectively. It’s more reasonable that set the treatment structure of immobilized microorganism after aerobic treatment.(3) Under pilot test conditions, the COD and ammonia removal rate of aerobic effluent arrived at 39.0% and 69.0% by immobilized microorganism, the removal of COD is not high, but the removal of ammonia is obvious, which reflected the distinct advantages of nitrogen removal of leachate by immobilized microorganism. Well removal efficiency of alkanes and carboxylic acids of landfill leachate was achieved by immobilized microorganism, and there are six dominant strains with strong organic pollutants degradation and denitrification ability in the reactor, which was identified as Acinetobacter Iwoffii, Sphingomonas paucimobilis, Stenotrophomonas maltophilia, Burkholderia cepacia group, Delftia acidovorans and Pantoea spp.(4)The results of application demonstration are coincided with pilot test, immobilized microorganism can effectively remove the ammonia nitrogen of landfill leachate, and have a certain removal ability for COD. When the HRT is 6 d, the removal of COD reached 33.2%, while the removal of ammonia arrived at 72.5%. The designed immobilized microorganism reactors treat landfill leachate had the characteristics of rapid start, short acclimation period, easy operation, low carrier filling ratio and stable operation. Immobilized microorganism can degrade landfill leachate effectively, it achieved efficient denitrification of landfill leachate, reduce the load of advanced treatment.