Methanization to stabilize waste placed in landfill: instrumentation of an industrial site.

Summary The storage of waste in a non-hazardous final waste storage facility (ISDUND) is an essential link in the management of our waste flows. Although organic matter recovery and recycling processes are developing, there is still a significant proportion of biodegradable waste in these waste streams. Bioactive ISDUNDs, also called bioreactors, are an alternative to "classic" ISDUNDs. In these installations, the leachate recovered from the bottom of the cell is generally reinjected at the top of the waste mass to percolate by gravity. The objective of the increase in humidity thus obtained is to accelerate the degradation of the waste, which remains one of the key parameters for obtaining optimal anaerobic biodegradation of the organic matter of the waste in ISDUND. The effect sought by the operators is both to increase the quantity of biogas produced and to concentrate its production over a shorter period of time in order to allow an easier recovery of the latter. These objectives also lead to an important issue which is the faster and more homogeneous stabilization of the waste mass. However, at the present time, few diagnostic tools allow to inform on the possible presence, in the waste mass, of more or less degraded zones. The use of these tools is also part of the problem of the end of the post-exploitation follow-up, which is fixed by law at a minimum of 30 years. The lack of parameters or quantitative data on these systems is an obstacle to the optimization of this management method. As part of a multi-partner research project, a set of physical measurement methods providing information on variations in water content and temperature is being deployed on bioactive ISDUND cells and combined with laboratory tests to optimize the cycles of reinjection sequences envisaged in situ. Started at the end of 2011, the instrumentation is now in its final phase of implementation on site. This article proposes to illustrate the methods and the approach implemented as well as to present the first results obtained during the on-site measurements, in particular concerning the evolution of the temperature and the electrical resistivity measurements.