Synthetic white spirit wastewater treatment and biomass recovery by photosynthetic bacteria: Feasibility and process influence factors

Photosynthetic bacteria (PSB) can assist with wastewater purification and useful biomass recovery without excess sludge. The feasibility of using PSB to treat white spirit wastewater was studied. The effects of the crucial process factors were also tested. The results demonstrated that using PSB to treat white spirit wastewater was feasible, and biomass production was achieved. PSB exhibited the ability to acclimatize to white spirit wastewater: they were tolerant of a high COD of 9100–25,600 mg l⁻¹ and an ethanol concentration of 0.5–2.0% (v/v). In addition, PSB were able to adapt to a pH of 5.0–8.0 and adjust the effluent pH. These characteristics were favorable for white spirit wastewater treatment. In performance improving study, dilution (reflux) was used as a strategy to improve the degradation effectiveness. Refluxing with a ratio of 300% was the optimal method. A similar treatment effect as an anaerobic process was achieved: the COD removal reached 76.02%, and valuable biomass instead of excess sludge was simultaneously obtained.