Evaluating the Performance of Tire- Derived Aggregate in the Leachate Collection Systems of Alberta Landfills

• Author / Creator

  Mwai, Marclus K

• The application of tire-derived aggregates as drainage media in leachate collection systems is an important component for recovery and recycling of waste tires. However, there are concerns that tire-derived aggregates may not perform adequately because of rapid clogging that is attributed to shape, particle size distribution and compressibility of the aggregates. Other factors associated with media clogging include biogeochemical characteristics of leachates, type and age of landfill, and climatic conditions. These factors are site dependent and, therefore, difficult to generalize. This study evaluated characteristics of leachates from municipal and industrial landfills in Alberta. It also determined properties of tire-derived aggregates that are processed from end-of-life tires from passenger cars and light trucks, medium trucks, and off-road vehicles. In addition, the study compared long term clogging behavior of tire derived aggregates with that of gravel using column tests for a period of up to 420 days. The study found that municipal landfills in Alberta had leachates of higher strength than those of industrial landfills and, therefore, greater potential for clogging. However, correlations between regional rainfall amounts and leachate strengths could not be established. Compression tests showed that the aggregates were highly compressible with strains of over 50% at 150 kPa. Hydraulic conductivity decreased with media compression; however, there were no significant differences between media types. Long-term clogging tests showed that leachate characteristics varied with depth but that they did not vary significantly with the type of media. Site specific pollutant fluxes were not determined, but based on past studies conducted to investigate relative importance of acidogenic and methanogenic leachates, leachate collection systems of Alberta’s municipal landfills were considered not susceptible to clogging. Based on the findings of compression tests, the study recommended that the as-spread thickness of tire-derived drainage layer should be 840 - 900 mm for a 20 m high landfill. It is further recommended that the key components of experimental set-up that included the design of the top steel plate, location of inline heater, arrangement of leachate pumps and the leachates storage period be configured to minimize variabilities and uncertainties in the study.

• Subjects / Keywords

  • Tire-Derived Aggregates
  • Sanitary Landfills
  • Clogging
  • Leachate Collection and Drainage Systems

• Graduation date

  Spring 2016

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R34F1MS35

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.