Human Pathogen Inactivation during the Composting Process
This multi-phase study examined the time-temperature criteria for composting operations as defined by many environmental guidelines and regulations (e.g. USEPA and CCME) to ensure compost safety. The study consisted of a series of full-scale experiments where the compost pile temperatures were monitored during typical large scale composting operations. Novel temperature probes wee developed to use in the experiments. It was found that pathogens can survive in cool zones within the compost piles and that pathogenic organisms can survive the high temperatures specified regulations by going into a "viable but not culturable" (VBNC) state.
Composting Diseased Tree Waste
The EWMCE evaluated protocols for composting diseased tree waste to prevent the spread of fungal pathogens, expand the sources of wood chips for biosolids composting, and reduce wood chips landfilled. The project resulted in identification of infected wood waste that could be used in the composting processes.
Feasibility of Using Treated Wood from Recycling Construction and Demolition (C&D) Waste as a Composting Feedstock
Clean wood is commonly used as a bulking agent for compost, but historically, treated wood has been landfilled due to potential environment impacts from potential toxic elements (PTEs). EWMCE investigated whether treated wood can be used as a compost bulking agent, specifically determining if there are ant adverse impacts and potential environmental impacts on the composting process and product quality. It was found that treated wood could be used in the process without negatively impacting processing rates or final product quality.
Contamination Removal from Organic Fration of Municipal Solid Waste (MSW) Composting Feedstock
This project compared the effects of different operation conditions of a system that uses trommel screens to separate materials (e.g. contaminants from the organic fraction of municipal solid waste). The goal was the increase processing throughout by minimizing clogging while improving the quality of feedstock. Various parameters (trommel angle, rotational speed, and feed rate) were investigated at full scale test for various trommel screen sizes (2", 3", 4", 5", and 9"). The work resulted in an adjustment of the minimum screen size from 2 to 4" diameter.
Impact of Pre-Treatment on Compost Quality: Focus on trace Metals
This research project investigated the benefits of pre-treatment and feedstock manipulation on compost quality, and determined the rates and mechanisms of transfer of metals from municipal sources, such as batteries and scrap metal into the final compost. Metal transfer rates from various materials within a composting environment were determined resulting in some materials, e.g. light bulb tails, being removed from the garbage waste stream and directed to EcoStations.
Drywall Waste Management
The housing construction industry in Alberta currently generates one-third of the province's waste. This multidisciplinary study developed best management practices for handling drywall waste, and produced a software tool for designers that optimizes material use and prevents waste.
Pathway of Carbon Monoxide (CO) Generation in Compost
Carbon dioxide (CO) production was studied in an enclosed co-composting facility. The study involved assessing the temporal and spatial variability of CO emissions and identifying and correlations between the CO emission rate and the biological and physiochemical properties of the compost through EWMCE laboratory scale incubation experiments. Practical strategies were developed to limit CO emissions to safe levels in other enclosed composting facilities.