Sustainable Landfills

Landfilling is a popular waste disposal method across urban communities, as it is economical and requires less infrastructure and no specialized collection services

Landfill Hazard

The amount of waste disposed in landfills across Canada was at 25.7 million tonnes in 2018.(i) Landfill leachate is a by-product from rainwater runoff in landfills, that is dangerous from both an environmental and health perspective. It is characterized by high chemical and biological oxygen demand and consists of undesirable substances such as organic and inorganic contaminants.

The contaminants seep through the soil into local waterways leading to the contamination of water supplies and spread of diseases. Landfills are also a contributor to greenhouse gas emissions (methane and carbon dioxide) through bacterial breakdown of organic waste, and also leads to an increase in odour and scavengers. Treatment of landfill leachate is essential for minimizing risks to the environment and human health.

Treatment of Landfill Leachate

Biocarbon (or biochar) is produced from a wide variety of organic feedstock, ranging from lignocellulosic materials to nutrient rich waste streams such as food waste. Biocarbon produced through the thermochemical conversion of organic waste and agricultural residue, provides a valuable pathway for the treatment of landfill leachate that will eventually lead to sustainable landfills. Properties such as a high number of pore spaces and large surface area, coupled with a high cation exchange capacity makes the biocarbon an efficient medium for the uptake of the heavy metals and toxic liquids in the landfill leachate.

Further, the high pH for biocarbon aids in neutralizing the acidity and corrosive nature of landfill leachate. This ensures that the leachate seeping into the soil and water table does not cause long term damage to the environment. Furthermore, the biocarbon exhibits excellent structural stability and microbial resistance; this ensures that the biocarbon does not break down over time and is stable in the environment for over hundreds of years.

Greenhouse Gas (GHG) Emissions

Methane is a highly potent GHG, with approximately 25 times the global warming potential to that of carbon dioxide. Biocarbon can also act as a suitable adsorbent for managing the harmful effects of landfills via uptake of organic and inorganic components from the leachate, and the uptake of methane and reduction of odour from the landfills.

Future Applications

Carbon Lock Tech has a patented process for the carbonization of organic matter to stable biocarbon, with a wide range of applications in agriculture (soil amendment and improving plant growth), concrete mixes (cement substitution), filtration and green infrastructure. The production of biocarbon from organic waste that is typically intended for landfills eases the burden on landfills amidst the depleting landfills. The team is working in collaboration with a professor at University of Manitoba for the investigation into the use of biocarbon toward treatment of landfill leachate and consequently sustainable landfills. 

[i] Solid waste diversion and disposal – Canada.ca