Ecological characteristics of sulfate-reducing system based on substrate-utilization

Continuous-flow experiment and batch test were conducted to investigate the ecological law of acidogenic bacteria and sulfate-reducing bacteria based on substrate utilization. Continuous-flow experiment was carried out in a continuous stirred tank biofilm reactor, molasses as the sole carbon resource and activated carbon was the biofilm carrier. The key parameters were shown as follows: COD=3000 mg/L, COD/SO₄=5.0 and HRT=ll hr. The experimental results show that successful start-up of the reactor can be achieved in 20 days and the sulfate removal rate can reach 95%-100%. The batch test shows that hydrogen and ethanol produced by AB are utilized easily by SRB, and ethanol is converted into acetic acid. AB is the predominant population in floe and SRB is the predominant one in the biofilm on activated carbon. So, SRB can directionally enrich on the carrier in this acidogenic sulfate-reducing ecosystem.