Landfill Leachate Toxicity to Oncorhynchus mykiss (Rainbow Trout) at the Merrick Landfill

At the Merrick Landfill, located outside of North Bay (Ontario, CA), an investigation into the potential for an environmental impact to the Little Sturgeon River as a result of landfill leachate discharge was undertaken using toxicity testing using 96 hour acute lethality on Oncorhynchus mykiss (Rainbow Trout). Landfill leachate may present a risk to receiving environments as it is comprised of an array of chemicals including organics, ammonia, and metals. Testing was conducted in three phases, firstly testing was completed on site throughout an existing natural attenuation zone where the presence of several groundwater seeps down gradient of the site had been identified to determine the effectiveness of the existing leachate control features at reducing the environmental risks. These tests indicated that the existing capture strategies were largely effective at reducing toxicity risks to the receiving environment. Testing was also completed on two pilot-scale hybrid-passive treatment systems to determine their effectiveness for leachate treatment. Summer performance of a constructed gravel wetland system was also shown to be effective at reducing the toxicity of the landfill leachate at the site. Lastly in order to support evaluation of leachate treatment requirements, a toxicity identification evaluation (TIE) was performed to determine the principle cause of toxicity within the leachate. Based on water chemistry analyses of samples collected at various locations at the site, the TIE identified ammonia toxicity as the primary source of toxicity in the leachate, with a secondary focus on metal toxicity.

Applying life cycle assessment to analyze the environmental sustainability of public transit modes for the City of Toronto

One challenge related to transit planning is selecting the appropriate mode: bus, light rail transit (LRT), regional express rail (RER), or subway. This project uses data from life cycle assessment to develop a tool to measure energy requirements for different modes of transit, on a per passenger-kilometer basis. For each of the four transit modes listed, a range of energy requirements associated with different vehicle models and manufacturers was developed. The tool demonstrated that there are distinct ranges where specific transit modes are the best choice. Diesel buses are the clear best choice from 7-51 passengers, LRTs make the most sense from 201-427 passengers, and subways are the best choice above 918 passengers. There are a number of other passenger loading ranges where more than one transit mode makes sense; in particular, LRT and RER represent very energy-efficient options for ridership ranging from 200 to 900 passengers. The tool developed in the thesis was used to analyze the Bloor-Danforth subway line in Toronto using estimated ridership for weekday morning peak hours. It was found that ridership across the line is for the most part actually insufficient to justify subways over LRTs or RER. This suggests that extensions to the existing Bloor-Danforth line should consider LRT options, which could service the passenger loads at the ends of the line with far greater energy efficiency. It was also clear that additional destinations along the entire transit line are necessary to increase the per passenger-kilometer energy efficiency, as the current pattern of commuting to downtown leaves much of the system underutilized. It is hoped that the tool developed in this thesis can be used as an additional resource in the transit mode decision-making process for many developing transportation systems, including the transit systems across the GTHA.