chapter 4: temperature inside the landfill

CHAPTER 2: LITERATURE REVIEW
2.1 Introduction
Operating a landfill as a bioreactor is an increasing trend in MSW management. One of
the problems frequently encountered is the difficulty in the assessment of the usefulness of the
liquid injection system. The injection system can be evaluated by measuring the waste moisture
content inside the landfill but measurement of moisture content poses many difficulties.
Moisture content can be measured by gravimetric technique which is considered to be the
most reliable among all the techniques. In gravimetric techniques, a MSW sample is excavated
from the landfill, weighed, dried and weighed again to find its moisture loss. Because waste is
heterogeneous, sampling is an extensive process. In-situ technologies like TDR, TDT, electrical
resistance, capacitance probe and neutron probe are quite commonly used to assess the moisture
content inside the landfill in spite of many disadvantages associated with them (Imhoff et al,
2007). These technologies often fail to provide accurate results and data collection can be costly.
2.2 Moisture Content
The moisture content of the solid waste is expressed in one of two ways (Tchobanoglous
et al., 1993). In the wet-weight method, the moisture content in a sample is expressed as a
percentage of the wet weight of the material; in the dry weight method, it is expressed as a
percentage of the dry weight of the material.
5