Study on Effects of Salinity on Biome Structure in SBBR Reactor

FENG Qingyuan; YANG Ying; WU Liang; ZHENG Yihan; CHEN Huijing; ZHU Manli; LI Weihua

doi:10.19672/j.cnki.1003-6504.1395.23.338

Abstract：This paper described an experimental study for treating salt containing wastewater with a bench-scale SBBR(se-quencing batch biofilm reactor).By gradually increasing salinity of the wastewater,the activated sludge of high salt-tolerance was acclimatized,and the treatment test of simulated salt wastewater was carried out with wastewater samples of five sorts of salinity:0 g/L,8 g/L,16 g/L,24 g/L and 32 g/L.The experimental results showed that with the increase of salinity gradient,the efficien-cies of removing NH4+-N,COD and TP decreased notably:in case where salinity was 32 g/L,and compared with salinity of 0 g/L,NH4+-N declined from 98%to 84%;COD from 98%to 73%;and TP from 97%to 47%.Additionally,the microbial activity,which was characterized by SOUR(specific consumption rate)and DHA(dehydrogenase activity)of biofilm,increased on con-dition of salinity being below 8 g/L,while decreased when salinity was up to greater than 8 g/L.Salinity made it possible to in-crease the content of extracellular polymer(EPS)in biofilms from 26.15 mg/g SS to 216.27 mg/g SS,among which polysaccha-ride(PS)content of TB-EPS grew most,and the increase of EPS could improve the resistance of microorganisms to salinity and the cells'protective effectiveness.It was found that under different salinity conditions there were growing three largest dominant phyla:actinomycetes,proteomycetes and patella bacteria in the biofilms,and the average relative abundance remained between 72%and 83%,among which the relative abundance of actinomycetes increased significantly with the increase of salinity,and the relative abundance of variant phylum decreased with the increase of salinity;the relative abundance of Kineosphaera,Microprui-naand TM7aincreased rapidly with the increase of salinity,and on the condition of salinity being up to 32 g/L,they became the three biggest dominant genera.To sum up,from the perspective of microbial community characteristics,the effects of increas-ing salinity on the structure and diversity of microbial communities were explored,the results could provide a theoretical basis for the further study on COD,NH4+-N and TP removal mechanisms of SBBR systems under high salinity stress.