Analysis On Microbial Diversity And Physicochemical Properties Of Dispersed Rural Domestic Wastewater Treatment Process With Multi-soil-layering System

In this paper,the effects of three factors of aeration,exogenous microorganisms and submersion on wastewater treatment effect of multi-soil layer were studied.The efficiency of removal of COD,BOD,TN,NH4+-N and TP reached 90%?97%,86%?94%,64%?47%,70%?100%,92%?100%when the removal efficiency of MSL systems were stable.According to the analysis of microbial diversity in soil mixture layering,the number of species number and community diversity were compared,and the significant influence of each factor on them was analyzed.Each factor has different effects on the number of species and community diversity.In terms of the number of species,aeration had no significant effect.Submersion had negative effect and the exogenous microorganisms had a certain degree of positive effect.In terms of community diversity,aeration and submersion had positive and significant effect,and exogenous microorganisms had negative impacf effect.The number of species in the soil mixture layering and the distribution of major species were counted.The number of species in the soil layer of multi-media system increased significantly compared with that of the original soil,the top ten speciesof phyla included:Proreobacteria,Firmicutes,Verrucomicrobia,Bacteroidetes,Actinobacteria.Acidobacteria,Cyanobacteria,Fibrobacteres,Chlorobi and Choroflexi.The abundance of functional bacteria including:organic removal bacteria,nitrification and denitrification bacteria and phosphorus removal bacteria were calculated.The effects of three factors and their interaction factors on the abundance of three functional species were analyzed.Aeration and submersion had different effects as they can changthe oxygen content in soil.Aeration had positive and significant effect on the abundance of all three functional species,while submersion had negative effect on the abundance of all three functional species.Exogenous microorganisms had no significant effect on the organic removal bacteria but had positive and significant effect on denitrifying bacteria and negative effect on phosphorus removal bacteria.At the same time,the similarities of species diversity between soil samples were compared.Aeration had the greatest influence on species diversity,followed by submergence,and the influence of exogenous microorganisms was the least.The BET surface area,pore volume and pore size of the zeolite in permeable layering were reduced compared to the original zeolite.The main material adsorbed on the zeolite surface and the substances causing clogging were the Extracellular Polymeric Substances(EPS)created by microorganisms.The beneficial results and experience in experiment were applied to the multi soil layering system in field project for sewage treatment.