Solubilization of particulate organic carbon during the acid phase of anaerobic digestion

Abstract

Hydrolysis of particulates to soluble substrates rather than bacterial growth was the rate-limiting step during the acid phase of anaerobic digestion of sewage sludge, and pH had a greater effect on the process than did influent solids concentrations, suggesting that digestability can be improved for highly variable feed sludges by separate phase digestion for acid production and CH/sub 4/ production. Carbohydrates were more readily degraded than nitrogenous materials, and lipids remained unaffected. A model of the acid phase of digestion is formulated.