Characteristics Of Microbial Community Dynamics Influenced By Ecological Factors In Sulfate-Reducing Bioreactor

The drainage of high sulfate wastewater resulted in serious ecological problems. Therefore, all nations in the world have promulgated strict laws to forbid high sulfate wastewater draining. At the same time, sulfate wastewater bio-treatment technique was born. Sulfate-reducing prokaryotes (SRP) were the main part in sulfate wastewater treatment. Their metabolism and function were influenced by many ecological factors, such as carbon resources, chemical oxygen demand (COD) to sulfate ratio, influent alkalinity and SRP inhibitors etc. Take into account the stability and high efficiency of bioreactor operation and sulfur reclaim, it is essential to completely understand the ecological factors influencing the high rate sulfate removal in acidogenic bioreactor and the important functional microbial populations.Modern molecular ecological techniques combined with chemical analysis of bioreactor were selected to demonstrate the dynamics of microbial populations and the relationship between microbial community structure and function under different operating conditions.Startup duration of bioreactors depended on the complexity and availability of carbon resources. The duration would be shortened by addition of the simple carbon resources that SRP utilized easily. The complex order of microbial community at steady state of bioreactor with different carbon resources were: seed sludge, acetic acid plus ethanol, molasses, glucose, and lactic acid. The proportion of SRP was correlated with sulfate-reducing rate. Terminal restriction fragments (TRF) of different carbon resources microbial communities were grouped two distant clusters, one contained molasses and glucose, another comprised of other communities of bioreactors by principal component analysis (PCA).After 35-day of startup, the sulfate-reducing rate of completely oxidized sulfate-reducing bioreactor reached to 80% fed with acetic acid plus ethanol. Some members of Desulfomicrobium , Desulfococcus , Aminomonas , Anaerolinea were predominant. When the ethanol in influent was removed, the relative quantity of SRP increased and band density of Desulfomicrobium sp.