Barcelona Study Measures Stability of Organic Waste
The composting research group at Autonomous University of Barcelona led by Antoni Sánchez, Ph.D., has investigated different methodologies to measure the stability of organic waste focusing on biological indicators, in a study funded by the Spanish Science and Education Ministry and the Catalonia Waste Agency.
Authors have presented an improved methodology in "Different Indices to Express Biodegradability in Organic Solid Wastes," the March-April 2010 issue of the Journal of Environmental Quality, which offers a reliable measurement of the biodegradable organic matter content in organic solid materials, useful for researchers and industrial operators. The journal is published by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America.
This study analyzed samples of food and garden wastes, mixed municipal solid wastes and sludge from wastewater treatment plants. The proposed methodology measures the respiration activity of microorganisms in the waste samples and establishes different respiration indices based on how fast those microorganisms consume oxygen and how much oxygen they have consumed.
The authors have established that respiration indices can be used as a measure of the biodegradable organic matter content and stability of organic materials and have defined the most suitable form of expression for those indices. Highly biodegradable wastes will have higher respiration rates, and wastes of low biodegradability will have lower respiration rates.
Research is ongoing at the Autonomous University of Barcelona to apply the developed methodology as a diagnostic tool in waste treatment facilities as well as to investigate the effect of stability on greenhouse gas emissions and the overall environmental impact of waste management systems. The authors highlight the need for an agreement of an international standard to be used by researchers and operators in the waste management field.