Screening And Application Of A Microbial Flora For The Degradation Of River Organic Pollutants

With the rapid development of economy and the accelerated process of urbanizat ion,China is facing a serious pollution of river.It is very important to use the local hi gh effective microbial bacteria to degrade organic pollutants to improve the river quali ty.In this study,a high effective complex microbial flora was cultivated and screened out by combining the advantage bacterium group technology with activated sludge tec hnology.In the experiment of urban river sewage treatment,the actual decontaminatio n effect of the microbial flora was proved to be effective.The main research results ar e as follows:(1)The complex microbial flora was highly effective on the degradation of COD and ammonia nitrogen.It included yeast,actinomycetes and bacteria.It’s growth culture medium and external culture conditions were identified for different bacteria.(2)In the process of river pollutants treatment,the organic pollutants removal eff iciency with single bacteria was affected by the concentration of the microorganism,t he number of feeding times,and the aeration condition.In the 50 L experimental devic e,the removal rate of COD of the single strain microorganism achieved the optimal ef fect at 83.58% when the microbial biomass is 2.5-3mL.With the increasing of the nu mber of impressions,the removal rate of COD remained stable.The decomposition ra tio COD and ammonia nitrogen under aeration condition(10d)increased to 68.01%,24.88%,respectively,which,are significantly better than under the condition of no aera tion.In addition,the microbial strain from the river sediment had a significant degrad ation rate of organic matter.(3)The microbial strains screened in this study are derived from the river channe l which is seriously polluted by urban domestic sewage.The selected microbial strains are suitable for the treatment of river sewage but also urban domestic sewage.In orde r to check the degradation rate of the pollutants.the screened strains were added to the most common activated sludge system to make four activated sludge system by addin g yeast,antinomies,bacteria,and multiple bacterial strains.When the hydraulic retent ion time is less than 5 hours,the COD decomposition ratio of all of four systems incre ased with the hydraulic retention time.In contrast,when the hydraulic retention time i s greater than 5 hours,the COD decomposition ratio kept at a stable level of 90.6%,88.5%,87.7%,93.9%,respectively.The multiple bacterial strains-activated sludge syst em performed more efficiency characteristic than the single bacterial strain-activated s ludge systems.In summary,the microbial flora cultivated and screened in this study w as effective on domestic sewage treatment.The multiple bacterial strains-activated slu dge system can effectively shorten the hydraulic retention time and improve the COD decomposition ratio.The results of this study provide an important reference for simil ar research and have high practical value.(4)The microbial strains screened out in the laboratory were used to degrade the river pollutantsput,and the treatment effect was obvious.