RESUMEN
A pilot-scale experiment was set up in the laboratory with the purpose of investigating the most relevant aspects of the anaerobic digestion of municipal solid wastes (MSW), which are necessary for the preparation of future feasibility studies and cost-benefit analyses. The experiment consisted of a comparative analysis among three different lines of operation, each one consisting of three anaerobic MSW reactors (with unit volume of 700 L): conventional landfill (line 1), raw leachate recycling (line 2), and integrated treatment, with seeded leachate recycling (line 3). So, a UASB reactor was installed in the integrated treatment line with the purpose of removing the organic load of the leachate of the MSW reactors and utilising the biological sludge produced for inoculation of the waste digestion. The endogenous inoculation promoted in line 3, by means of recirculation of the leachate and return of the exceeding biological sludge produced in the UASB reactor, has favoured the initial fermentation stage and also the acceleration of the methanogenic phase.