Environmental Engineering Reference
In-Depth Information
Chapter 16
Liners for Waste Containment Facilities
16.1. Introduction
Modern municipal solid waste (MSW) facilities are typically designed with
barrier systems intended to limit contaminant migration to levels that will result in
negligible impact. In order to approach the design of such systems in an appropriate
way, it is important to discuss the role and functions of the components of these
barriers, which are essential for a safe disposal of polluting materials.
There are various design philosophies available for the design and management
of a MSW landfill as indicated by Rowe
et al
. [ROW 95] and Manassero
et al
.
[MAN 00]. One philosophy (referred to as passive) provides a cover system that is
as impermeable as possible (see Figure 16.1) and as soon as possible after the
landfill has ceased operation, so as to minimize the generation of leachate. This
approach has the benefits of minimizing both the amount of leachate that must be
collected and treated, and the mounding of leachate within the landfill. It also has
the disadvantage of extending the contaminating lifespan. With low infiltration it
may take decades or centuries before the field capacity of the waste is reached and
full leachate generation occurs.
An alternative philosophy (referred to as active) is to allow as much infiltration
as would practically occur (Figure 16.2). This would quickly bring the landfill to
field capacity and allow the removal of a large proportion of contaminants (by the
leachate collection system) during the period when the leachate collection system is
most effective and is being carefully monitored (e.g. during landfill construction
