TREATMENT OF LANDFILL LEACHATE IN SBR SYSTEMS: ANALYSIS OF BIOMASS ACTIVITY BY MEANS OF RESPIROMETRIC TECHNIQUES

In the last decades landfilling has been the main method of municipal solid waste (MSW) disposal in many countries. MSW landfills are usually considered as a large biological reactor where the MSWs undergo anaerobic digestion producing gas and liquid emissions. Aged, or mature leachate, which is produced by older landfills, can be very refractory; for this reason mature leachate is difficult to treat alone, but it can be co-treated with sewage or domestic wastewater. The aim of the study was to investigate the feasibility of co-treatment of landfill leachate and synthetic wastewater in different percentages, in terms of process performance and biomass activity, by means of respirometric techniques. Two sequencing batch reactors (SBR) were fed with synthetic wastewater and different percentages of landfill leachate (respectively 10% and 50% V/V in SBR1 and SBR2). The obtained results showed a good organic carbon removal efficiency for both reactors; ammonia removal efficiency showed different trends between SBR1 and SBR2, probably due to inhibition factors exerted by high landfill leachate percentage present in SBR2.