Semester

Spring

Date of Graduation

2021

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Civil and Environmental Engineering

Committee Chair

Leslie Hopkinson

Committee Member

John Quaranta

Committee Member

Seung Ho Hong

Abstract

To ensure the sustainable use of one of West Virginia’s precious resources, conscientious long-term management of residual waste is of immense importance. This thesis examined two main topics: i) the dewatering process of acid mine drainage (AMD) sludge, and ii) an investigation of soil loss predictions of a reclaimed coal refuse impoundment.

The first aspect of this thesis addresses clarification and remediation of AMD prior to disposal is a prominent component to preventing runoff and seepage of environmentally detrimental byproducts. To examine the effects of flocculation and dewatering more closely by means of geotextiles, an AMD sludge was analyzed. The raw AMD was sourced from the underground mine, treated by precipitation at an approximate pH of 3.2, and clarified to a pH of 6.7 using calcium hydroxide (lime). The supernatant is settled through a series of ponds. Then the sludge produced during the clarification process was dredged, flocculated with polymers concentrated at 20 ppm to create filterable flock, and dewatered through a series of geotextile tubes. Following the dewatering process, geotechnical property testing was performed in accordance with ASTM International Standards to determine the predominately lean, elastic silt soil characteristics of the sludge.

The second component utilizes the USDA’s Water Erosion Prediction Project (WEPP), a process-based computer modeling program created to anticipate soil displacement, loss, and deposition during singular or continuous storm events, was utilized to evaluate the runoff and sediment loss of a reclaimed coal refuse impoundment. To identify the unique characteristics of the impoundment, field measurements of infiltration, ground cover, and soil samples were completed and analyzed. Using TR-55 single storm predictions, the annual soil loss was predicted to be 0.397 tons for a two-year return period, 0.661 tons for a five-year return period, 0.879 tons for a 10-year return period, 1.245 tons during a 25-year return period, 1.588 tons from a 50-year event, 1.922 tons during a 100-year event, and finally a total of 2.525 tons of soil lost during a 500-year return event from the impoundment. Due to the minimal slope (i.e., 2.4%) it can be predicted that the impoundment will not experience substantial amounts of soil loss for the foreseeable future as long as vegetation is maintained.

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