(best examples and good practices) on household organic waste ...

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the non-biodegradables <strong>and</strong> any recyclables. Next, the residual waste is
prepared for biological treatment by comminution, mixing <strong>and</strong>, if necessary,
moistening. The biological stage effects extensive biological stabilization of the
waste. The waste is exposed to atmospheric oxygen to induce aerobic
decomposition, or by breaking it down in the absence of atmospheric oxygen in
anaerobic fermentation process. The last step is deposition of the treated
material.
There are several advantages of MBT: reduction of the waste volume,
lengthening the useful life of the l<strong>and</strong>fill, while reducing the rate of gas
formation, hence reducing the danger of l<strong>and</strong>fill fires <strong>and</strong> reducing the leachate
load (The Deutsche Gesellscheft fur Technische Zusammenarbeit – GTZ.,2009).
3.3.4. L<strong>and</strong>fill system
Nowadays solid waste l<strong>and</strong>fills are of a ‘dry tomb’ design. The waste is isolated
from water that can generate leachate from solid waste, which may cause
groundwater pollution. The main concept of dry tomb is to isolate waste from
the environment in a compacted soil <strong>and</strong> plastic sheeting tomb. Plastic
sheeting is a thin layer of HDPE (high –density polyethylene). It is combined
with a compacted soil-clay layer to form composite liner. A typical double
composite liner l<strong>and</strong>fill containment system is shown in (Figure 21.). (Fred Lee.,
2010)
Figure 21.: Conceptual design cross section
(Epperson Waste Disposal., 2009)