Anaerobic treatment of wastewater

Claim 1

In a process for the anaerobic biological growth treatment of wastewater containing pollutants comprising conducting the wastewater through at least one reactor containing anaerobic microorganisms retained on a particulate carrier material to biologically convert organic material in wastewater under anaerobic conditions to sewer gas containing methane and carbon dioxide, the improvement comprising conducting the wastewater through an agitated bed reactor employing a mechanical agitator having a rotational velocity of 1-10 rpm, so as to not comminute the particulate carrier material and so as to accelerate mass transfer and conversion of organic pollutants, said reactor containing the anaerobic microorganisms retained on said particulate carrier material having a particle size of 10-50 mm in diameter, a density of 10-200 kg/m 3 and open macropores throughout of a diameter of 1-5 mm, the carrier material being made of polyurethane foam or foam rubber and the anaerobic microorganisms growing on said open macroporous carrier material in a decentralized fashion due to said open macropores, substantially uniformly throughout the carrier whereby a high mass transfer surface is obtained and excessive localized growth is precluded, and wherein the process is conducted in a reactor wherein the carrier material is non-fluidized.