Innovative Two-Stage Process for the Recovery of Energy and Compost from the Organic Fraction of Municipal Solid Waste (MSW)

Abstract

An innovative system for stabilizing the organic fraction of municipal solid waste (OFMSW) has been documented on a pilot scale at the Civil Engineering Department of the University of California at Davis. The system involves the combined methods of high-solids anaerobic digestion and aerobic composting for the recovery of energy and the production of compost from the OFMSW. The performance of the high-solids anaerobic reactor was monitored for three mass retention times. The anaerobic digester was operated under extreme as well as normal conditions. The performance of the aerobic compost unit was monitored based on the physical and chemical characteristics of the final humus by-product. In general, the combined process was very stable at a 30 d retention time and is capable of removing essentially all of the biodegradable fraction of the organic fraction of MSW. A biogas production level of up to 6 liters per liter of active volume of reactor was achieved. The process stability and gas production decreased slightly when the retention time was reduced to 15 d. The output from the second stage is a fine humus-like material with a thermal content of about 14.80 MJ/kg.

Strategies for the anaerobic digestion of the organic fraction of municipal solid waste: an overview

“…In a two-stage process investigated by Kayhanian and Tchobanoglous (1993) the aerobic post-treatment with a HRT of 3 days was mainly used for a further volume reduction by water evaporation, while the degradation of volatile solids was not significant after OFMSW was treated anaerobically for 30 days. Pera et al (1991) co-composted the effluent from anaerobic digestion of OFMSW together with fresh OFMSW for further biostabilization of the waste.…”

Digesting the Organic Fraction of Municipal Solid Waste: Moving From Mesophilic (37°C) To Thermophilic (55°C) Conditions

“…Many experiences are reported in the literature regarding two possible ranges of temperature in which the process is carried out: mesophilic (35-37°C) and thermophilic (50-60°C). Furthermore, combined anaerobic and aerobic decomposition produces good quality compost if the organic fraction of municipal solid wastes (OFMSW) is first treated under thermophilic anaerobic conditions (Kayhanian & Tchobanoglous 1993, Kostenberg & Marchaim 1993, O'Keefe et al 1993, Vallini et al 1984. Furthermore, combined anaerobic and aerobic decomposition produces good quality compost if the organic fraction of municipal solid wastes (OFMSW) is first treated under thermophilic anaerobic conditions (Kayhanian & Tchobanoglous 1993, Kostenberg & Marchaim 1993, O'Keefe et al 1993, Vallini et al 1984.…”

Compostagem Doméstica Avaliada Por Meio Da Temperatura E Relação C/N

“…Segundo Kayhanian et al (1993) a relação C/N ideal para ser usada em solos é entre 15 e 20. Sendo assim, quanto a utilização do composto como adubo, os recipientes com serragem obtiveram os resultados mais próximos do recomendado.…”