Affiliations: State Key Laboratory of Pollution Control and Resource
Reuse, Tongji University, Shanghai 200092, China | Department of Chemical Engineering, "National" Taiwan
University, No.1, Sec 4, Roosevelt Road, Taipei, Taiwan 10617, China
Abstract: Landfill is the major disposal route of municipal solid waste (MSW)
in most Asian countries. Leachate from landfill presents a strong wastewater
that needs intensive treatment before discharge. Direct recycling was proposed
as an effective alternative for leachate treatment by taking the landfill as a
bioreactor. This process was proved not only considerably reducing the
pollution potential of leachate, but also enhancing organic degradation in the
landfill. However, as this paper shows, although direct leachate recycling was
effective in landfilled MSW with low food waste fraction (3.5%, w/w), it failed
in MSW containing 54% food waste, as normally noted in Asian countries. The
initial acid stuck would inhibit methanogenesis to build up, hence strong
leachate was yielded from landfill to threaten the quality of receiving water
body. We demonstrated the feasibility to use an assisted bioreactor landfill,
with a well-decomposed refuse layer as ex-situ anaerobic digester to reducing
COD loading in leachate. By doing so, the refuse in simulated landfill column
(2.3 m high) could be stabilized in 30 weeks while the COD in leachate reduced
by 95% (61000 mg/L to 3000 mg/L). Meanwhile, the biogas production was
considerably enhanced, signaling by the much greater amount and much higher
methane content in the biogas.
