Landfill Engineering Could Lead to Contamination

The necessity to manage leachate and rubbish heap gas will continue till the wastes contained within a site don't have the potential to cause issues in their express location. In fact the pressure to maximise dump gas and thus improve the amount energy acquired from waste is bound to continue to rise.

This fact is emphasized by the Waste Regulations and Environment Agency Allowing needs, with dump operators being legally obliged to introduce and maintain long term aftercare regimes which, in the case of rubbish heap gas control and leachate management, may continue for many decades.

It is not possible to define exactly the point at which wastes can not be considered to pose a potential environmental threat. The period necessary for a dump to reach environmental stability is much related to the character of the wastes and the rate of the decomposition processes at work within the body of wastes.

It is a recognized fact the rate of stabilization can be maximised by raising the moisture content of the landfill, but this is tough to do without allowing a zone of saturation to develop within the rubbish heap. This may cause many metres of leachate being permitted to develop above the fundamental liner.

This conflict, which is a real one and not just unproven, needs to be addressed by the dump industry.

This highlights the necessity for the rubbish heap scientist to work closely with the landfill engineer to reach an OK degree of compatibility.

There is no reason why, with careful design, this target shouldn't be achieved whilst at the same time optimizing the benefit to be gained from picking up and harnessing a useful resource in the form of rubbish heap gas.

Leachate recirculation has incredible benefits by reducing the strength of the leachate, particularly with a very young leachate where the free-of-charge anaerobic digestion it receives in such a rubbish heap as it percolates through the saturated layers is excellent pre-treatment.

Of course to gain recirculation one essentially has to have, if you like, a reservoir to drag on within the base of the dump and therefore by definition one would have some standing leachate level there to pull on. The other point of course is another, in a way, problem that is that of the hydraulics of heavily compressed waste at the bottom of a dump, which is truly quite impervious, and really quite impervious, and actually trying to get water to pass through such waste in a controlled demeanour is a hard one which neither the industry or its regulators have got to grips with yet.
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