Grantee Research Project Results
Passive Treatment of Metal-rich Waters through Enhanced Wetland Technologies: A Field Scale Pilot Project
EPA Grant Number: R829423E02Title: Passive Treatment of Metal-rich Waters through Enhanced Wetland Technologies: A Field Scale Pilot Project
Investigators: Nairn, Robert W.
Institution: University of Oklahoma
EPA Project Officer: Chung, Serena
Project Period: July 15, 2002 through July 14, 2004
Project Amount: $160,000
RFA: EPSCoR (Experimental Program to Stimulate Competitive Research) (2001) RFA Text | Recipients Lists
Research Category: EPSCoR (The Experimental Program to Stimulate Competitive Research)
Objective:
Degraded surface and ground water quality are major environmental concerns at many active and abandoned mining operations. Passive treatment technologies (i.e., those that rely on natural biogeochemical and microbiological processes to ameliorate mine drainage problems) provide a viable treatment alternative at abandoned sites. Our overall objective is to implement a pilot-scale field project to examine passive amelioration of metals-contaminated mine waters in ecologically engineered wetland ecosystems. We propose to employ a series of statistically replicable wetland mesocosms (small-scale ecosystems) under controlled field conditions to address a poor quality lead and zinc mine discharge at the Tar Creek Superfund Site in Ottawa County, OK. Our goals include: 1) determination of the most effective sequence of sequential unit processes; 2) determination of effects of physical variables (e.g., hydraulic retention time) on treatment effectiveness; and 3) enhancement of specific treatment processes via biotic and abiotic optimization.
Approach:
The experimental design includes alternating mesocosm sequences of three passive treatment cell designs: vertical-flow wetlands, surface-flow wetlands and vertical-flow limestone cells. Mine drainage will be metered into parallel sets of three mesocosms consisting of all combinations of the three treatment cell designs in triplicate. Treatment effectiveness under various hydrologic flow rates (and thus hydraulic retention times) will be evaluated by adjusting water inflow rates during year 1. Results of biweekly water quality and quantity sampling will be used to calculate mass removal rates and to focus further efforts at determining specific biogeochemical treatment mechanisms. Vertical profile data, underlying substrate/porewater collections, vegetation sampling, and microbiological activity will supplement these data. The second phase in year 2 will include similar sampling under controlled flow rates with additions of waste labile carbon sources (e.g., whey) to bolster microbial activity or alkaline waste products (e.g., cement kiln dust) to stimulate additional metal retention. These combinations will be tested to further optimize system performance.
Expected Results:
The expected results of these efforts will be: 1) to provide fundamental and needed results on cost-effective and sustainable passive treatment technologies for mine drainage pollution abatement at hard rock mine sites; 2) to elevate well-researched passive treatment technologies to the "next-generation" by utilizing biogeochemical performance data to design targeted sequential treatment systems; and 3) to lead to substantial reductions in risk exposure at the Tar Creek Superfund Site, recognized as U.S. EPA's most difficult remediation challenge.
Publications and Presentations:
Publications have been submitted on this project: View all 1 publications for this projectJournal Articles:
Journal Articles have been submitted on this project: View all 1 journal articles for this projectSupplemental Keywords:
water, watersheds, groundwater, ecological effects, metals, restoration, remediation, life-cycle analysis, environmental chemistry, biology, ecology, hydrology, geology, analytical, mining, Oklahoma, EPA Region 6., RFA, Scientific Discipline, Geographic Area, Water, State, Watersheds, Environmental Chemistry, Water & Watershed, Ecology and Ecosystems, mining impacted watershed, restoration planning, water quality, Oklahoma (OK), constructed wetlands, groundwater, wetland restoration, metals, biogeochemical studyProgress and Final Reports:
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.