Treatment of mechanically sorted organic waste by bioreactor landfill: Experimental results and preliminary comparative impact assessment with biostabilization and conventional landfill

• Full scale hybrid-bioreactor landfill was analyzed for MSOF management.
• DRI lower than 1000 mgO2/kgVS h was achieved within 5 months.
• Methane concentration in landfill gas achieved promptly values higher than 50% v/v.
• Impact resulted reduced up to 50% compared to biostabilization and conventional landfill.

Treatment and disposal of the mechanically sorted organic fraction (MSOF) of municipal solid waste using a full-scale hybrid bioreactor landfill was experimentally analyzed. A preliminary life cycle assessment was used to compare the hybrid bioreactor landfill with the conventional scheme based on aerobic biostabilization plus landfill. The main findings showed that hybrid bioreactor landfill was able to achieve a dynamic respiration index (DRI) < 1000 mgO2/(kgVS h) in 20 weeks, on average. Landfill gas (LFG) generation with CH4 concentration >55% v/v started within 140 days from MSOF disposal, allowing prompt energy recovery and higher collection efficiency. With the exception of fresh water eutrophication with the bioreactor scenario there was a reduction of the impact categories by about 30% compared to the conventional scheme. Such environmental improvement was mainly a consequence of the reduction of direct and indirect emissions from conventional aerobic biostabilization and of the lower amount of gaseous loses from the bioreactor landfill.