When using a thermoplastic process, the waste is dried, heated,
and then dispersed through a heated plastic system. Bitumen is
the most common matrix material ~Meegoda et al. 1992; Meegoda
1999!. However, paraffin and polyethylene have also been
employed. The final mixture is then cooled and usually buried in
a containment system. Organic chemicals that could react with the
plastic matrix leading to physical deterioration cannot be disposed
of using this technique. The process employs specialized equipment,
is energy intensive, and requires trained operators. The elevated
temperature of the process limits the types of materials
that can be incorporated into the matrix ~e.g., citrates!. Typically