Development of Salt-resistant Bentonite as a Novel Bottom Liner Material for Marine Waste Disposal Facilities
폐기물 해상 최종처분장의 해저 바닥 차수층 조성을 위한 신형 내염성 차수재 개발

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공과대학 건설환경공학부
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서울대학교 대학원
학위논문 (박사)-- 서울대학교 대학원 : 공과대학 건설환경공학부, 2018. 8. 박준범.
With the increasing of solid waste and insufficient capacity of current on-land landfill in Korean, marine waste disposal has provided a new treatment method for municipal solid waste. In the process of waste disposal, leachates resulting from the waste landfill can cause secondary environmental pollution, and installation of a basal liner under a landfill site is essential to block and reduce permeation of leachate from flowing into the subsurface environment.

Bentonite is an impervious liner material that is widely used in landfills at present. However, there are several problems when using bentonite as a liner system material in coastal areas such as drying shrinkage cracks and high permeability under saline conditions. In addition, because of bentonite’s powder state and high liquidity, using bentonite to construct bottom liners in coastal areas is difficult and construction quantities are usually large.

To overcome these problems, the purpose of this research is the development of a salt-resistant bentonite and novel basal liner system for marine waste disposal facility. The novel bottom liner material include core material and coating material in which mixtures of bentonite, sepiolite, and guar gum are used to overcome the shortcomings in bentonite to realise a high water-resistance and a hydraulic conductivity of below 1 × 10-7 cm/s under saline water conditions.

Using drying shrinkage cracking tests, swelling index tests, and hydraulic conductivity tests, the optimal mixing ratio of bentonite, sepiolite, and guar gum in salt-resistant bentonite was obtained. The optimum mixing ratio of bentonite, sepiolite and guar gum is confirmed as 76:19:5 in salt-resistant bentonite. The hydraulic conductivity, swelling behavior and adsorption capacity of salt-resistant bentonite were evaluated. To enhanced the workability of salt-resistant bentonite, a novel concept material for bottom liner was presented. Using salt-resistant bentonite as slurry cover around cement beads to make spherical particle, then it’s hydraulic conductivity, adsorption capacity and swelling behavior were evaluated.

Three-dimensional water tank testing have been used to investigate the in situ performance of spherical particles bottom liner in laboratory. The permeability, adsorption capacity and load-settlement behavior of novel bottom liner systems were evaluated under simulated field conditions. According to the envisaged simulation results, the feasibility and effectiveness of the novel liner material for marine waste disposal facility has been verified.

Keywords: Marine waste disposal, Salt-resistant bentonite, Saline water condition, Novel bottom liner, Hydraulic conductivity, Swelling capacity, Adsorption capacity

Student Number: 2014-31435
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College of Engineering/Engineering Practice School (공과대학/대학원)Dept. of Civil & Environmental Engineering (건설환경공학부)Theses (Ph.D. / Sc.D._건설환경공학부)
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