Aerobic Biostabilization of Old MSW Landfills

Many years after the end of the cultivation phase, landfills may generate intense odours, toxic and explosive gases and heavily-polluted leachate. A wide-spreading trend in the management of MSW landfills is represented by the forced aeration of wastes in order to achieve the stabilization, reducing the negative environmental impact of uncontrolled sites (old landfills which can be definitely considered as contaminated sites) and the management costs of controlled and working facilities. One of the most interesting challenges is the in situ waste aerobic stabilization, obtained by insufflating air into the wastes. The aerobic metabolism is energetically convenient in comparison with the anaerobic one, it is characterized by a higher degradation rate and a temperature increase (like in the compost production). In order to obtain an aerobic biostabilization of waste in landfills, several air injection systems have been developed and applied in the last years, like Biopuster^© or AEROflott^® patented systems. The feasibility of the application of in situ biostabilization must be evaluated by means of different tests, in order to evaluate the main characteristics of the wastes. The main parameters to be evaluated are the biological stability and the air permeability of the wastes. In March 2006, the biological stability of the wastes located in the Trinitapoli Landfill, Italy, has been evaluated by the Politecnico di Torino. Black Index Test and Static Respirometric Index Test have been performed in the laboratories of the Politecnico. On the basis of the obtained results, the potential biogas production from the examined landfill was estimated together with the potential volume reduction.