| abstract |
An improved process and apparatus for producing biogas having a high methane content from a feed or substrate. Feed material is injected into a reactor having anaerobic microorganisms to form a bulk liquid in the reactor. The oxidation-reduction potential, pH, and temperature of the bulk liquid and the methane, carbon dioxide, hydrogen sulfide, and flow of the biogas is monitored. The amount of the feed material (substrate) fed to the reactor is adjusted in response to the monitoring parameters of the bulk liquid and biogas. A biomass recycle is provided to the reactor, thus increasing the reactor biomass retention time, or solids retention time within the reactor. |