Methane production from industrial wastes by two-phase anaerobic digestion

Abstract Although much attention has been paid to energy recovery from municipal sewage, industrial liquid waste is a larger potential source of renewable energy. In certain industrial sectors it is possible, in theory to displace almost all of the purchased fuels by recovering the energy content of the waste in suitable forms and utilizing them within the plant. Anaerobic digestion is probably the only available process that can achieve the dual goal of energy recovery from aqueous wastes and stabilization of the pollution load. This paper presents data illustrating the limitations and vulnerability of the conventional digestion process to this end, and discusses the application and advantages of an innovative and advanced fermentation system, two-phase digestion. Results of operation of bench-, pilot- and full-scale two-phase digestion plants with several types of industrial liquid wastes are presented. Industrial sectors that could benefit from commercial-scale application of this new process are indicated.