[Methane Cycle Anaerobic Membrane Bioreactor with Desulfurization for Treating High Sulfate Organic Wastewater at...

The operational performance of a methane cycle anaerobic membrane bioreactor (MCAnMBR) with desulfurization for the treatment of high sulfate organic wastewater was investigated. Within 63 days, the MCAnMBR with desulfurization was started successfully at a normal temperature of 26-34℃. The two main problems at the beginning of debugging, sludge loss and increased pH, were effectively solved by adjusting the gas path system and adding methanol to the inflow for acclimation. The results show that the inflow concentration of SO₄^2- from 650 mg·L^-1to 5800 mg·L^-1can be treated well with the conditions of hydraulic retention time (HRT)=120 h, a volume loading of 3.61-4.36 kg·(m³·d)^-1, pH of 7.18-7.61, and temperature of 23.3-25.4℃. The effluent chemical oxygen demand (COD) concentration could be lowered to 23 mg·L^-1. The total removal rate of COD could remain stable at 96.23%-99.77%, and the SO₄^2- conversion rate was about 83.83%-95.51%. These results indicated that the MCAnMBR reactor with desulfurization could effectively solve the problem of secondary sulfide inhibition. A gradient experiment revealed that the high Na₂SO₄ inflow could be treated when the influent COD ranged from 18000 mg·L^-1to 21000 mg·L^-1, the concentration of SO₄^2- ranged between 9082 mg·L^-1 and 9600 mg·L^-1, and the COD/SO₄^2-=2.