Anaerobic acidogenesis of wastewater sludge.

Abstract

This paper has presented a general discussion on the theory and operating principles of the two-phase digestion process with special emphasis on the acidogenic phase of the total process. Stable, steady-state operation of the two-phase process is possible with wastewater sludge for extended time periods. It is possible to separate enrichment cultures of acidogenic and methanogenic organisms in isolated environments or phases by kinetic control involving manipulation of dilution rates and imposition of limits on the microbial generation time. Hydrolysis and acidification of waste water sludge are the predominant reactions in the acid-phase digester. Under mesophilic conditions, acidogenesis of activated sludge occurs at a pH value of 5.7, and an ORP.Ec, of -240 mV. Acidified activated sludge may be gasified efficiently in a methane digester at a detention time of 6.46 days. 7 figures, 7 tables. (DP)