Location

Chicago, Illinois

Session Start Date

4-29-2013

Session End Date

5-4-2013

Abstract

A new generation of sustainable landfill was designed and constructed in the City of Calgary, Canada to achieve sustainable municipal solid waste (MSW) management. This sustainable landfill called “biocell” involves sequential operation of a landfill cell to produce methane gas during the first stage of anaerobic degradation and in-situ composting within the cell footprint. Once methane recovery is minimal, the second stage aerobic degradation initiated by injecting air through methane recovery system and finally landfill is mined for resource and space recovery in the third stage. The resources that can be recovered include compost like material and recyclables such as plastics, metal, and glass. Non-recovered waste but with high energy content can be used as refuse derived fuel. The practice of this approach will no longer require the need to allocate valuable land for new landfills on an on-going basis. There is leachate re-circulation and environmental monitoring to enhance biodegradation in the biocell. The biocell eliminate problems of ground/surface water contamination, landfill gas emission and the need for new land to use for waste disposal. However, currently there is limited knowledge on landfill mining and in order to estimate the best time to initiate landfill mining a comprehensive mathematical model was developed. The model developed solves the mass and energy balance of waste decay, which computes the rate of gas generation, change of gas and gas flux through the system. This study focuses on anaerobic phase of biodegradation of biomass and the degradation of the biomass was assumed to follow first order kinetics. The decomposing bio mass is represented as cellulose for energy balance computation, which is a major constitution of the MSW. The degradation of bio mass due to micro-organisms generates methane, carbon dioxide and water as the final products and the reaction is exothermic. In this model using the decay of waste computed from mass balance and cellulose as equivalent chemical representing the waste a relationship between the mass degraded with time was established. The heat released due to anaerobic decay is computed and hence computes the increase in biocell temperature. Then selecting the representative decay constant for the computed biocell temperature, the decomposition of waste was computed for the next time step. The above computation is continued in order to obtain the landfill settlement, temperature and the movement of landfill gas and leachate.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conference on Case Histories in Geotechnical Engineering

Meeting Name

Seventh Conference

Publisher

Missouri University of Science and Technology

Publication Date

4-29-2013

Document Version

Final Version

Rights

© 2013 Missouri University of Science and Technology, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Apr 29th, 12:00 AM May 4th, 12:00 AM

A Comprehensive Model for Anaerobic Degradation in Bio-Reactor Landfills

Chicago, Illinois

A new generation of sustainable landfill was designed and constructed in the City of Calgary, Canada to achieve sustainable municipal solid waste (MSW) management. This sustainable landfill called “biocell” involves sequential operation of a landfill cell to produce methane gas during the first stage of anaerobic degradation and in-situ composting within the cell footprint. Once methane recovery is minimal, the second stage aerobic degradation initiated by injecting air through methane recovery system and finally landfill is mined for resource and space recovery in the third stage. The resources that can be recovered include compost like material and recyclables such as plastics, metal, and glass. Non-recovered waste but with high energy content can be used as refuse derived fuel. The practice of this approach will no longer require the need to allocate valuable land for new landfills on an on-going basis. There is leachate re-circulation and environmental monitoring to enhance biodegradation in the biocell. The biocell eliminate problems of ground/surface water contamination, landfill gas emission and the need for new land to use for waste disposal. However, currently there is limited knowledge on landfill mining and in order to estimate the best time to initiate landfill mining a comprehensive mathematical model was developed. The model developed solves the mass and energy balance of waste decay, which computes the rate of gas generation, change of gas and gas flux through the system. This study focuses on anaerobic phase of biodegradation of biomass and the degradation of the biomass was assumed to follow first order kinetics. The decomposing bio mass is represented as cellulose for energy balance computation, which is a major constitution of the MSW. The degradation of bio mass due to micro-organisms generates methane, carbon dioxide and water as the final products and the reaction is exothermic. In this model using the decay of waste computed from mass balance and cellulose as equivalent chemical representing the waste a relationship between the mass degraded with time was established. The heat released due to anaerobic decay is computed and hence computes the increase in biocell temperature. Then selecting the representative decay constant for the computed biocell temperature, the decomposition of waste was computed for the next time step. The above computation is continued in order to obtain the landfill settlement, temperature and the movement of landfill gas and leachate.