The scenario underlying the transportation
study is based on the main assumed scenario for
landfill design. In recent years the density of waste
in semi-trailers fell to 325 kg/m
3
, thus proving that
the waste density is decreasing in Tehran. This makes the compaction more favorable. In addition
the amount of waste is increasing due to increasing
in population and public welfare. Because of lack
of yearly and continuous data on waste density, it
is assumed that with the increasing percentage of
non-degradable materials in waste the density of
waste in the horizon of study would be 250 Kg/m3
that would mean a middle range, reported for a
middle income country (Rudolf, 2000). Transfer
station alternatives include an extensive range of
facilities from a simple soil platform to a multistory building with sophisticated instruments.
Consequently, the potential technologies used for
these transfer stations vary considerably.
In Table 3 the advantages/ disadvantages and
the common usage of transfer containers are
discussed (EPA, 2002). One of the main points
that should be considered in waste storage is the
leachate generation. In tipping floor and surge pits
systems because of significant amount of waste
moisture, there would be considerable amount of
leachate to collect and treat. This will create
substantial cost of leachate treatment in order to
release it to the surface water runoff drainage
system (Ehrig, 1989).
The process of loading transport vehicles is
the main issue of waste transfer which has a great
effect on the whole transportation system. In Table
4 the advantages, disadvantages and the common
usage of various alternatives are discussed (EPA,
2002).