Co-disposal of electronic waste with municipal solid waste in bioreactor landfills

Three pilot scale lysimeters were adopted to evaluate the stability pattern and leaching potential of heavy metals from MSW landfills under the E-waste co-disposed condition. One lysimeter served as control and solely filled with MSW, whereas the other two lysimeters were provided with 10% and 25% of E-waste scraps (% by weight), respectively. The reactors were monitored over a period of 280 days at ambient settings with continuous leachate recirculation. Stabilization pattern of carbon appears to be more than 50% in all the three lysimeters with irrespective of their operating conditions. Iron and zinc concentrations were high in leachate during bioreactor landfill operation and correlating with the TCLP leachability test results. In contrast, Pb concentration was around <0.6 mg/L, but which showed maximum leaching potential under TCLP test conditions. But, no heavy metal accumulation was found with leachate recirculation practices in lysimeters. Mobility of the metal content from the E-waste was found to be amplified with the long term disposal or stabilization within landfills. The results showed that the TCLP test cannot be completely reliable tool for measuring long-term leachability of toxic substances under landfill condition; rather landfill lysimeter studies are necessary to get the real scenario.

Research highlights
► More than 50 % of organic matter reduction was occurred without any accumulation of heavy metal contents in leachate proved the effective functioning of landfill bioreactors for co-disposal of E-waste.
► The TCLP test is batch test and cannot provide the real conditions existing in landfills has been proved and suggested to accomplish biological factors along with the existing physic-chemical based approach for long term pollutant leachability monitoring.
► Further, study need to be considered in the field to accomplish the heavy metal behaviors in landfill and their interactions with the biological agents.
► The study outcome also specified the importance of landfill simulation experiments for real time data acquisition.