Final disposal of sludge.

The [G 1 450] article on the characteristics and treatment of sewage sludge sets out the means of producing, in an industrial context, a minimum volume of "quality" sludge, since it is ultimately a question of paying for the disposal, or even storage, of a waste product whose cost per unit will be all the greater the higher its potential for olfactory, microbiological or toxic nuisance.

It is now time to examine the ways in which the industrial company or its delegated service provider can dispose of, or preferably recycle, the sludge or other waste produced in the course of its activities, and thus find the best match between the type of sludge and the possible outlets, of which there are four:

• recycling in agriculture ;

• recycling in another industry;

• thermal elimination ;

• technical landfills for household waste, or ordinary industrial waste, and special industrial waste.

This research will take into account all technical, economic, regulatory and environmental constraints. The latter term, to be considered in its broadest sense, includes the human environment, which can in some cases call into question choices that are nevertheless optimal in technical, economic and ecological terms.