LIFE CYCLE ASSESSMENT OF DIFFERENT PROCESSES AND TECHNOLOGIES FOR LEACHATE TREATMENT: A CASE STUDY

Abstract

Different technological schemes for treating the leachate generated by an existing landfill were compared in a life cycle perspective. On-site advanced processes based on reverse osmosis and evaporation were compared to conventional off-site co-treatment with civil sewage in a wastewater treatment plant. Evaporation system required 40 kWh/m3 of electricity and 18,5 kWh/m3 of heat whereas reverse osmosis needs only 8,5 kWh/m3 of electricity. On the other hand, the amount of concentrate liquid returned by the former was about 0,03 m3/m3 instead of the about 0,30 m3/m3 returned by the latter. Life cycle analysis showed that the impact categories most affected by the different options were human toxicity, both non-cancer and cancer, together with fresh water ecotoxicity. Larger contribution to the impacts was given by the off-site co-treatment of the leachate and/or liquid concentrate with civil sewage in the waste water treatment plant. On-site treatment schemes based on reverse osmosis and evaporation showed quite similar impacts even if the lower ones were always detected for the former mainly as a consequence of lower energetic consumptions.