Dissertation/Thesis Abstract

Evaluation of the effectiveness of zeolite in remediation of impacts of coalbed natural gas coproduced water on soil
by Belbase, Shashidhar, M.S., University of Wyoming, 2011, 120; 1500383
Abstract (Summary)

This research study examined the impact of high sodicity CBNG coproduced water on a soil's hydraulic characteristics (infiltration), chemical properties in relation to sodium adsorption ratio (SAR), electrical conductivity (EC), and pH, and the subsequent impact on these properties by the use of Bear River (BR) zeolite. A batch adsorption isotherm study revealed that the adsorption of sodium (Na+) was determined by the type of anions associated with Na+, indicating that bicarbonate (HCO3-) had a more positive impact than Cl- ions on the adsorption of Na+. Fitting this with the Langmuir and Freundlich models revealed that the coefficients of Na+ adsorption were higher for HCO3- than Cl-. An adsorption kinetics study indicated that adsorption of Na+ by BR-zeolite was an inverse function of particle size, with smaller particles having greater adsorption capacities. The greatest efficiency was found with the particle size 1.3–1.5 mm which removed about 72% of the Na+ in the first 30 minutes of reaction compared to 59% with the zeolite particle size 2.0–2.5 mm. The SAR was also reduced from 30 to below 10 (mol/m3)1/2 in the first 30 minutes of batch reaction. Both a laboratory columns study and a field experiment of a falling head permeameter infiltration test indicated that the negative impact of infiltration through soil in CBNG coproduced water can be at last partially mitigated by BR-zeolite.

There was a significant difference in the infiltration of CBNG coproduced water through boreholes with zeolite and without zeolite at the 95% confidence level (p=6.87*10-7<0.05 for phase I and p=2.76*10 -6<0.05 for phase II). An analysis of influent and effluent water from the column study and the post-treatment analysis of soil saturated paste extracts from the 0-5, 5-15, 15-30, 55-65, and 95-105 cm intervals below the boreholes, revealed BR-zeolite reduced the SAR and the EC of soil and water. By reducing the potential harmful impacts of high concentrations of Na+ in CBNG water on the physicochemical properties of soil and groundwater, it is possible that a Ca2+ and Mg2+ rich zeolite lining at the bottom of an infiltrated containment pond can enhance the beneficial use of coproduced water for groundwater recharge and other possible uses. It can be concluded from this study that a BR-zeolite treatment of CBNG water can be an effective method for mitigating the harmful impacts caused by high Na+ concentration on the physicochemical characteristics of soil and water.

Indexing (document details)
Advisor: Urynowicz, Michael A.
Commitee: Brant, Jonathan A., Vance, George F.
School: University of Wyoming
Department: Civil & Architectural Engineering
School Location: United States -- Wyoming
Source: MAI 50/02M, Masters Abstracts International
Subjects: Environmental Studies, Civil engineering, Environmental engineering
Keywords: Coalbed natural gas, Infiltration, Salinity and sodicity, Sodium adsorption ratio, Water treatment, Zeolite treatment
Publication Number: 1500383
ISBN: 978-1-124-92509-7
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