High Quality Composts by Means of Cocomposting Of Residues from Anaerobic Digestion

Abstract

Advanced treatment of residues from anaerobic digestion of leftovers and kitchen waste originating from an industrial waste treatment plant was carried out by means of cocomposting in order to reveal potential synergistic effects. After a retention time of two weeks in the anaerobic reactor, microbial activity of the residues remained high. The biogas produced is of use in combined heat and power generation. Lab-scale experiments in the liquid phase have demonstrated “cracking” of the anaerobic stabilized organic matter under aerobic conditions. The advanced aerobic treatment of residues from anaerobic digestion by means of cocomposting leads to high quality composts. The addition of output material to biowaste from the separated bin collection may improve the formation of humic substances. Extractable humic acids are considered to represent a reliable parameter in describing high quality composts. Thus, the improvement of humic acid formation by means of composting is a goal to be achieved. Process control was performed by assessing parameters such as loss of ignition, total organic carbon, nitrogen and humic acid content as well as by modern analytic methods like FT-IR spectroscopy and thermogravimetry.