Greenhouse gas from organic waste composting: emissions and measurement

There is actually common consensus to use biological technologies for the treatment of organic wastes. For instance composting involving the aerobic biological stabilization of organic wastes is gaining popularity. The amount of materials and the variety of wastes composted is increasing fast. However composting is a process emitting gases some of which being greenhouse gases (GHG) that favour global warming. In particular carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) are responsible for the global warming potential of composting. A part of these gases can be abated by low-cost biological technologies such as biofiltration. This review compiles all the points related to the emission of GHG from composting processes, from detection and measurement to minimization and abatement. We focus on measurements of GHG to obtain reliable emission factors for designing composting technologies. This will help to compare waste treatment options based on integrated tools such as Life Cycle Assessment (LCA). A chapter discusses C and N dynamics in the compost, and implications on emitted C and N gases. Finally we review the best available practices to minimize the GHG emissions from composting. We also present the final treatment of composting gases.The authors wish to thank the financial support of the Spanish Ministerio de Ciencia y Tecnologia (Project CTM2009-14073-C02-01/02).Peer reviewe