The feasibility of biosolids composting for the City of Winnipeg

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Beyene, Mulubrhan
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To investigate the potential for biosolids composting in the City of Winnipeg a feasibility study was initiated by the University of Manitoba. A process design for the biosolids windrow composting facility using leaves as a bulking agent was conducted. The principal factors affecting the facility design were the biosolids quantity, water content, and the carbon-to-nitrogen ratio (C/N). The process design was carried out based on the 1994 biosolids production of the City of Winnipeg. In total the City processed 48,702 wet tonnes of dewatered biosolids at an average of 26% total solids in 1994. Assuming an optimal moisture content of 55% for the feedstock mixture and using leaves at an assumed 20% moisture content and recycle at 40%, the CM ratio was calculated to be 26. This value falls within the acceptable range of C/N ratio for rapid composting rate. Because leaves may not provide sufficient structural strength to the pile during windrow composting an additional bulking agent such as wood chips may be required to provide an adequate structural integrity to the windrows. (Abstract shortened by UMI.)