Screening And Application Of Heterotrophic Nitrification Bacteria And COD_CrDegrading Bacteria In Landfill Leachate

As the efficiency of the wastewater treatment reactors was highly influenced by the high concentration of NH4+-N and CODCr in the landfill leachate,two types of functional bacteria or bacterial community that could remove the ammonia nitrogen and CODCr of leachate were screened directionally,and their actual treatment effect of leachate was studied,so as to provide theoretical basis for construction of the high efficient functional bacteria agents of landfill leachate.The dissertation mainly contents:screening and identification of heterotrophic nitrification bacteria;the removal characteristics of NH4+-N of the heterotrophic nitrification strain and bacterial community;screening of CODCr degrading bacteria;treatment effect of leachate by the two types of functional bacteria.And the main results were as follows:1.The three heterotrophic nitrification bacteria with high removal efficiency of NH4+-N were respectively named as XS16,XS68 and XS76,which were screened firstly by the transparent ring method of Nash reagent,and then by the quantitative determination.Strain XS16 and XS68 were both identified as Oligella sp,and XS76 as Pseudomonas sp.by morphologic observation,physiological biochemistry experiment,and the idendification of 16S rRNA gene sequence respectively.2.After 24h cultivation of XS16,XS68,XS76 and bacterial community,there was very little accumulation of nitrate nitrogen,and no accumulation of hydroxylamine and nitrite nitrogen.3.The NH4+-N removal of heterotrophic nitrification bacteria and bacterial community was free from inoculum;The optimum carbon source of the three bacteria and strains was Sodium succinate,and all of them could not only utilize organic nitrogen,but also remove the Ni4+-N.Higher C/N ratio,better removing effect.And the optimum C/N ratio of bacterial community was 10.When the shaking speed was 160?180 r/min,pH was 6?9,temperature was 30?34 ?,the three strains and bacterial community all achieved preferable NH4+-N removal effect,and the the highest removal rate were all above 90%.When the temperature was 15 ?,XS68 and bacterial community still had good treatment effect,and the highest removal rate were respectively 16.49%and 82.92%,which suggested that they had the ability to tolerate low temperature.4.With CODCr removal rate as the indicator,6 strains were screened,which could remove the sodium humate and their CODcr removal rate were above 8;With the enzyme activity of the amylase,protease,lipase and cellulose as the indicator,14 strains were screened,which included four protein degradation bacteria,three starch degradation bacteria,four cellulose degradation bacteria and three fat degradation bacteria.With the degradation rate of the PAHs and DEP as the indicator,16 strains were screened.The Antagonism between strains was investigated by the filter paper method,11 strains that were of antagonistic effect were screened.5.When the concentration of TN and CODCr was 140.53 mg/L and 99.67?398.68 mg/L,respectively,after 2 days' treatment,the highest removal rate of biological enhancement group was 48.42%and 77.75%,respectively.Meanwhile,the removal rate of TN and CODCr could both reach above 47%high compared with the control group.When the concentration of NH4+-N?TN and CODCr was 98.02?797.36 mg/L?43.18?1405.3 mg/L and 5740.80?9568,respectively,after 8 days'treatment,the highest removal rate of NH4+-N?TN and CODCr was 75.28%?75.28%and 82.71%,respectively.Meanwhile,the removal rate of biological enhancement group could reach above 16%?15%and 37%high,respectively,compared with the control group.Therefore,It had good biofortification effect.