chapter 4: temperature inside the landfill

CHAPTER 1: INTRODUCTION
1.1 Background
Municipal Solid Waste (MSW) consists of used items such as product packaging, grass
clippings, furniture, clothing, bottles, food scraps, newspapers, appliances, paint, and batteries.
According to the Environmental Protection Agency (EPA), 245 million tons of MSW were
produced in USA in 2005 which is approximately 4.5 pounds of waste per person per day. In the
United States, 32 percent is recovered and recycled or composted, 14 percent is burned at
combustion facilities, and the remaining 54 percent is disposed of in landfills (EPA, 2006),
indicating the importance of landfills in MSW management strategies in the USA.
The traditional approach to sanitary landfill design and operation involves encapsulating
and storing waste in a manner which minimizes entry of moisture into the landfill. This approach
minimizes the leachate production but the degradation of MSW is slowed. A better approach for
MSW management is the bioreactor landfill in which leachate produced is recirculated back into
the landfill. In case leachate is not generated in sufficient quantity, addition of other liquid, such
as groundwater may be necessary. Liquid injection enhances moisture content and conditions
(temperature and pH) conducive for degradation, settlement, methane production and biological
decomposition of the waste inside the landfill (Eliassen, 1942; Rees, 1980; Buivid et al, 1981;
Townsend et al, 1996; Wreford et al, 2000; Sam and Onay, 2001).
Although many researchers have experimented with bioreactor landfills in the laboratory,
and many of them are in operation, still several difficulties exist in their operation. As liquid is
being injected into the landfill, one of the concerns is the efficacy of the injection system. It
would be beneficial for the landfill manager to know the best way to inject the liquid which
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