Contaminant impact assessment and the contaminating lifespan of landfills

Abstract

Some of the factors to be considered in performing impact assessments for proposed municipal and non-hazardous waste landfill sites are discussed. These factors include the effect of the mass of contaminant, infiltration, and attenuation in the hydrogeologic system on the contaminating lifespan of a landfill. The potential impact of fracturing of the soil separating the landfill from an underlying aquifer is examined. The influences of a compacted clay liner and (or) a natural, intact clayey layer below the fractured soil are examined. The concept of developing "triggers" to initiate leachate control measures, and the associated potential impact on groundwater, is discussed in the context of the potential design life of the underdrain system in a landfill.

Analysis of Solute Transport from a Source with Finite Leachable Mass

“…The evolution of the chloride concentration in the leachate leaving the waste is plotted in Figure . The results are essentially identical to the analytical solution of Rowe ().…”

“…An infiltration rate of 0.102 m/year was specified for the demonstration analysis. As shown in Figure , results of the numerical model match the Rowe () analytical solution. The Rowe () solution is founded on the assumption that advection is the only transport process that leaches mass from the waste.…”

“…As shown in Figure , results of the numerical model match the Rowe () analytical solution. The Rowe () solution is founded on the assumption that advection is the only transport process that leaches mass from the waste. As the infiltration rate through the source is reduced, diffusion becomes progressively more important as a leaching process.…”

“…The results of the analysis are shown in Figure . In this case there are significant differences between the Rowe () solution and numerical results. However, the numerical results match closely the results of the general analytical solution of Booker and Rowe ().…”

Evaluating landfill aftercare strategies: A life cycle assessment approach

“…One of the easiest actions that an operator can take to reduce these timescales is to not utilise a low permeability cap, thereby allowing a higher flux of water to enter a site. Perhaps uniquely, based on Rowe (1991) landfill regulations in Ottawa, Canada require the installation of top covers that allow >150 mm infiltration per year (Ministry of the Environment, 2008). More active measures to promote the addition of moisture to the waste mass involve the controlled addition of recirculated leachate or liquids from other sources, such as freshwater or wastewater effluent.…”