Landfill sites - Impacts and outlook

Everyone has an idea of what a "landfill" is, because every society has always needed a means, a place, to dispose of its waste. Those in the know know that our grandfathers' habit of throwing their garbage, and more generally all waste, carelessly into the first hole that came along, has changed a great deal over the last few decades.

During this period, the field of landfills was modernized by the application of precautionary and preventive principles to protect the environment. It has become technical and economic, yet continues to be the subject of diverse and controversial "passions".

In France, as in many other countries, the most modern sites still rub shoulders with "abandoned" waste dumps. Leaving a few items of garbage, debris or bulky objects in the corner of a wood or barely concealed in any excavation whatsoever constitutes an illegal dump. It is estimated that France is faced with some six thousand illegal dumps of varying sizes.

Deliberately choosing an unconcealed place where waste is piled up without any special precautions to protect the environment, and without authorization, constitutes a crude dump.

To combat these two bad ways of disposing of waste, regulations turned their attention to this mode of disposal, and landfill became controlled (1975 to 1981). This was the expression of a desire and a need to monitor the effects and impacts on the environment.

Gradually, technical rules were laid down concerning the choice of containment sites, the recovery of gaseous and aqueous effluents for treatment prior to discharge, the selection of wastes admitted, the control and monitoring of operations, etc. To reflect this modernization, the landfill was then called a technical landfill (1980-1990).

Since the 1990s, very important and radical technical measures have been taken:

• choice of impermeable sites for waste containment ;

• waterproofing and drainage of site bottoms, sides and roofing;

• a strong selection of waste categories;

• fixed discharge conditions in terms of content and flow for biogas and leachates, which requires high-performance collection and treatment systems prior to discharge;

• monitoring of sites for at least 30 years after closure, to manage the post-mining period.

To mark this "revolution" in the field, regulations have broken with the past by giving a new name: waste storage centers. This implies that waste is stored in a confined area, with no exchange with the surrounding environment (groundwater, soil and atmosphere)....