Optimization of polymer-amended fly ash and paper pulp sludge millings mixture as a landfill liner alternative

Slim, Gerjen I (2017) Optimization of polymer-amended fly ash and paper pulp sludge millings mixture as a landfill liner alternative. Masters thesis, Northern Arizona University.

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Abstract

In 2012 the City of Flagstaff partnered with researchers at the Dept. of Civil Engineering, Construction Management and Environmental Engineering at Northern Arizona University to develop a mix design utilizing sludge derived from the manufacturing of recycled paper millings and fly ash as components of a landfill cap. This research has been extended to amend paper millings and fly ash with polymers to determine whether it is a suitable replacement for a clay based EPA Subtitle D-approvable landfill liner. An EPA Subtitle D landfill liner is not to exceed a hydraulic conductivity of 1 × 10 -7 cm/sec in order to assure that leachate release is minimized.Cinder Lake Landfill (CLL) serves several communities in Northern Arizona and is managed by the City of Flagstaff. CLL does not have a reliable source of clay required to construct an approved landfill liner, which is necessary for the upcoming 108-acre landfill expansion. However, CLL receives approximately 100 tons of recycled paper millings daily from a local tissue manufacturing plant. Paper millings are currently used as daily cover at the landfill and was tested for use as a component of a landfill cap. Incorporating polymers in alternative materials such as paper millings and fly ash has the potential to meet performance criteria and be approved by state and federal regulators, and has the potential to save the City millions of dollars over conventional composite liners of geomembrane and clay.Different mixtures of paper millings, fly ash, soil and multiple polymers were subjected to testing for the following: Hydraulic Conductivity, Shear Strength, Proctor Compaction, Optimum Moisture Content, Specific Gravity, Organic Content, Atterberg Limits (plasticity), and USCS Soil Classifications. The optimal mixture of paper millings and fly ash was then blended with a range of polymer concentrations. The goal of this project is to find an optimal mix of paper millings to achieve regulatory standards related to hydraulic conductivity, along with other desirable properties such as strength and flexibility.This project determined the polymers increased the hydraulic conductivity of the materials subjected to this treatment. The polymers did not appear to significantly influence the strength of the paper millings and fly ash mixture. This study was able to determine that paper millings should be amended with highly plastic clays to reduce the hydraulic conductivity below 1 × 10-7 cm/sec. The mixture which met the EPA hydraulic conductivity requirement included at minimum 15% bentonite clay and were compacted with Modified Proctor compactive effort.

Item Type:	Thesis (Masters)
Publisher’s Statement:	© Copyright is held by the author. Digital access to this material is made possible by the Cline Library, Northern Arizona University. Further transmission, reproduction or presentation of protected items is prohibited except with permission of the author.
Keywords:	Geotechnical; Hydraulic conductivity; Landfill liner; Paper millings; Recycled paper
Subjects:	T Technology > TA Engineering (General). Civil engineering (General)
NAU Depositing Author Academic Status:	Student
Department/Unit:	Graduate College > Theses and Dissertations College of Engineering, Forestry, and Natural Science > Civil Engineering, Construction Management, and Environmental Engineering
Date Deposited:	21 Mar 2018 05:15
URI:	http://openknowledge.nau.edu/id/eprint/5171

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