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

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3.3.8. Bioreactor l<strong>and</strong>fill
A bioreactor l<strong>and</strong>fill is a sanitary l<strong>and</strong>fill that uses microbiological processes to
transform <strong>and</strong> stabilize the decomposable organic waste within 5 to 10 years of
implementation, compared to 30 to 100 years for dry Subtitle D l<strong>and</strong>fills (those
that accept MSW <strong>and</strong> so-called nonhazardous industrial waste). To promote
waste stabilization, moisture (usually leachate) is added. Stabilization means
that waste does not produce l<strong>and</strong>fill gas any more through the biochemical
reactions of bacteria utilizing some of the organic components in wastes as a
source of energy (Fred Lee., 2010).
There are three different types of bioreactor l<strong>and</strong>fill configurations: aerobic
leachate is re-circulated into the l<strong>and</strong>fill <strong>and</strong> air is injected, anaerobicleachate
is also re-circulated into the l<strong>and</strong>fill but biodegradation occurs in the
absence of oxygen, hybrid - aerobic-anaerobic treatment to degrade organics in
the upper part of the l<strong>and</strong>fill <strong>and</strong> collect gas from lower part (EPA., 2004).
3.3.9. Environmental <strong>and</strong> health impacts
The major concern regarding l<strong>and</strong> filling sites is the release of gases <strong>and</strong>
leachates. The pollution of the aerial systems occurs through release of gas. The
contamination of terrestrial <strong>and</strong> aquatic systems comes through leachates <strong>and</strong>
l<strong>and</strong>fill gases (El-Fadel et al., 1997, Tsiliyannis., 1999).
The quantity of gases released from l<strong>and</strong>fills has decreased due to the
installation of covers. These covers not only stop the gases from spreading into
the atmosphere, but can also recover <strong>and</strong> use them in energy recovery systems,
e.g. methane that can be burned <strong>and</strong> produce energy. The properties of the
leachates vary greatly depending upon the different abiotic factors like
temperature, moisture, aeration conditions <strong>and</strong> diversity of waste, etc. We will
go through the main pollutants generated in leachates.
The impermeable layer of a l<strong>and</strong>fill has a lifetime of 30 - 40 years. Even if state
of the art technology is used the lifetime of a l<strong>and</strong>fill cover is limited. The
majority of the toxic emissions will be released during the lifetime of the
covers. However, the toxic substances stored will not disappear <strong>and</strong> the toxic
emissions won’t stop completely. (Ludwig et al., 2003,).