Landfilling of pretreated municipal solid waste by natural convection of air and its effects

Abstract

The problems of leachate treatment and landfill gas (LFG) emissions are increasing gradually. Reducing the hazard before emplacement, pretreatment of municipal solid waste (MSW) prior to landfilling has become very important for the conventional landfill. In this study, pretreated mixed un-shredded MSW by the natural convection of air was employed to assess the aerobic pretreatment suitability. To study the effects of pretreated waste on landfill behavior, landfill simulation reactor (LSR) was developed at laboratory scale; pretreated MSW was placed in it. In a LSR, the behavior of aerobically pretreated waste disposal on a landfill was simulated. The LSR was operated for more than 9 months. The LSR operating phases were analyzed together with the consolidation of the leachate and gas production. The leachate collected was analyzed for pH, BOD (biochemical oxygen demand), COD (chemical oxygen demand), NH₃-N and trace metals. The gas collected was analyzed for CH₄ and CO_2. The COD and BOD values were reduced to 1850 mg/L and 235 mg/L respectively within 5 months respectively. The maximum landfill gas (LFG) generation was observed about 60 m³ per ton dry matter (DM) of MSW. This work demonstrates that pretreatment is significantly effective in reducing the landfill emissions that is LFG; and leachate quality was improved in terms of COD and BOD.

Keywords:

• Pretreatment of MSW
• unsorted municipal solid waste
• biodegradation
• landfilling.

Acknowledgement

This work is acknowledged to Research Analysis Foundation, Tsinghua University, Beijing China, for extending cooperation in laboratory facilities.

Notes

^a Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant^{[ 29 ]}except organic matter (carbon) and humic acids data from Control Standards for Urban Wastes for Agricultural Use^{[ 30 ]}and Fertilizer Application Guideline for Green Food Production^{[ 31 ]}