Quantification and control of restrictive ecological factors in acidogenic de-sulfate bioreactor

As an artificial microbial ecosystem, acidogenic de-sulfate bioreactor has high efficiency of sulfate removal. The restrictive ecological factors, including causing ecological factors, such as COD/SO₄^2- ratio and sulfate loading rate (Ns), and following ecological factors, such as pH value, oxidation reduction potential (ORP) and alkalinity (AlK) have significant effect on the ability and stability of acidogenic de-sulfate bio-reactor. Continuous flow and batch test were carried out to investigate the quantification and control of COD/SO₄^2- ratio, Ns, pH vale, ORP and ALK in acidogenic de-sulfate bioreactor supplied with molasses wastewater as sole organic carbon source and sodium sulfate as electron donor. It was demonstrated that in order to maintain high sulfate removal rate (SRR) of 80% to 90%, the restrictive factors should meet all the requirements as follow:k_COD/SO4^2- ratio≥ 2.0, Ns≤7.5 kg (m³·d)^-1, pH=5.7-6.2, ORP=-320-420 mV and ALK=1500-2000 mg/L.