Unsaturated flow parameters of municipal solid waste

Area of Science:

• Geotechnical Engineering
• Environmental Engineering
• Waste Management

Background:

• Municipal solid waste (MSW) landfills present environmental challenges like leachate pollution and gas emissions.
• Accurate prediction of MSW unsaturated properties is vital for landfill design and environmental control.

Purpose of the Study:

• To review recent studies on the unsaturated properties of MSW.
• To identify limitations in experimental methods and theoretical models.
• To propose estimation methods for key unsaturated property parameters.

Main Methods:

• Literature review of experimental studies and theoretical models for MSW unsaturated properties.
• Summarization of available data on intrinsic permeabilities, water retention curves, relative permeabilities, and anisotropy.
• Development of estimation methods for water retention curve parameters (θLm, θLr, nv, α) and proposed relationships for pore connectivity (l) and anisotropy (k) with porosity.

Main Results:

• Experimental methods face limitations in sample size, requiring large test apparatuses.
• Theoretical models are constrained by changes in waste composition and particle size due to biodegradation.
• Proposed estimation methods can define effects of porosity, waste composition, and particle size distribution on unsaturated properties.

Conclusions:

• The study provides a summary of MSW unsaturated properties and proposes new estimation methods.
• Further experimental data is required to improve the accuracy and applicability of these estimation methods, particularly concerning waste composition and particle size distribution.
• Addressing these data gaps will enhance the design and management of MSW landfills.