Enhanced production of volatile fatty acids by adding a kind of sulfate reducing bacteria under alkaline pH

Abstract

Anaerobic digestion could make sludge stable and harmless, and the volatile fatty acids (VFAs) produced from it. The objective of this study was to reduced sludge production and realize the resource utilization of VFAs through enhance anaerobic sludge fermentation by adding sulfate reducing bacteria (SRB) under alkaline pH. Under the neutral and alkaline pH, SRB was added into the sludge fermentation liquid with sole stock solution and sterilization treatment respectively, while the liquid without any additives was used as control. The results indicated that obvious increase of the production of VFAs was observed after adding SRB under alkaline pH. And, more protein and polysaccharide were obtained which were the main substrates for the production of VFAs. The concentration of ammonia nitrogen (NH₄⁺-N) and phosphate (PO₄^3--P) were also increased with the addition of SRB. So, a high yield production of VFAs could be achieved through the addition of SRB + alkaline pH.

Keywords: Alkaline pH; Anaerobic fermentation; Sulfate reducing bacteria; Volatile fatty acids; Waste activated sludge.