Landfill Case Study

1.0 INTRODUCTION

Landfill is the disposal of waste into or onto land. Today, landfill sites are constructed and operated to strict technical standards in order to reduce environmental effects. Landfills have four types that is sanitary landfill, municipal solid waste landfills, construction and demolition waste landfills and industrial waste landfill. The Environmental Protection Agency (EPA) isrequired, under the Environmental ProtectionAgency Act, 1992 to specify and publish criteria andprocedures for the selection, management, operationand termination of use of landfill sites.

In the past, many of the problems associated with landfills occurred as a result of non engineered facilities and poor management. There are many potential environmental

The most appropriate landfill methodology for a region will be determined based on local conditions and factors and these will be identified in the early stages of the site risk assessment process.There are a range of proven engineering solutions that currently exist to overcome environmental issues and there is experience to show they can work. It is the job of the landfill designer to satisfactorily demonstrate to the department that the proposed design will afford an acceptable level of environmental protection.

2.3 Groundwater

Release of leachate, together with landfill gas migration, poses the greatest hazard and the most severe consequences for a landfill operation. All groundwater must be considered a valuable resource (whether it is currently used or not) and therefore must be protected from contamination by pollutants from the landfill.A preferred site for a landfill is one that minimises the risk of groundwater pollution by providing a natural, unsaturated attenuation layer beneath the liner for contaminants that may leach through it. This means that sites with naturally attenuating soils, such as those in clayey areas, are preferred to those that do not have such soils, such as in sandy

Clay A low permeability clay layer in a lining system retards water movement and absorbs exchangeable cations. Some of the properties of the soil measured to determine its suitability as a low permeability liner are particle size distribution and plasticity (described by the soil plasticity index) and cation exchange capacity. A key consideration is the potential for desiccation and subsequent cracking.

Geosynthetic Clay Liner(GCL) To provide a low permeability layer to limit contaminant migration, reduce water ingress into the landfill and to control landfill gas migration. They are generally used as a compliment with clay in the lining system. The assessment for the suitability of a GCL in a lining system should consider water and gas flow, contaminant transport and stability including the assessment of hydraulic conductivity, gas permeability, chemical compatibility, diffusion and shear