Hedin R.S.,Hedin Environmental |
Hedin B.C.,Hedin Environmental
Mine Water and the Environment | Year: 2014
Approximately 30% of the Earth’s oceans support low rates of primary production because of low Fe concentrations. The fertilization of these waters with Fe has been proposed as a tool for creating phytoplankton blooms, increasing carbon fixation, and sequestering carbon in deep ocean waters. This paper reviews the status of the ocean iron fertilization (OIF) concept and assesses the opportunity it may provide to mining companies and mine water professionals who regularly deal with large quantities of Fe. Using data produced by large OIF experiments, calculations are provided regarding the efficiency of Fe additions for carbon fixation and the quantities of Fe that would be needed if OIF became an accepted practice. The gross value of Fe used in OIF projects is calculated from the current value of carbon credits and salmon and tuna fisheries. If the OIF concept advances, the huge demand for Fe that will be created may justify reconsideration of mine water treatment practices that produce more pure Fe solids than is the case with conventional treatment technologies. © Springer-Verlag Berlin Heidelberg 2014.
Hedin R.,Hedin Environmental |
Weaver T.,Hedin Environmental |
Wolfe N.,Hedin Environmental |
Weaver K.,Hedin Environmental
Mine Water and the Environment | Year: 2010
The Anna S coal mine complex in Tioga County, PA, produces drainage with a pH of 2.8-3 6 containing 3-36 mg/L Al, 1-36 mg/L Fe, and 6-9 mg/L Mn. In 2003, the Babb Creek Watershed Association installed two systems that passively treat three discharges from the mine complex. Both systems contain four parallel vertical flow ponds followed by aerobic wetlands. The vertical flow ponds contain a total of 35,483 t of limestone and 4,913 m3 of organic substrate. During the last 6 years, the systems have treated an average of 1,971 L/min of flow to neutral pH with 135-146 mg/L of alkalinity (as CaCO3), with less than 1 mg/L of Al and Fe, and 2-4 mg/L of Mn. The vertical flow ponds have generated alkalinity at rates of 32-53 g/m2/day as CaCO3. No seasonal variation in treatment effectiveness has been observed, despite relatively harsh winter seasons. The total cost of the passive systems was $2. 5 million (US). The 20 year projected unit treatment cost, including periodic replacement of the organic substrate, is $403-618 per t (as CaCO3) of net alkalinity generated. © 2010 Springer-Verlag.
Chapman E.C.,University of Pittsburgh |
Capo R.C.,University of Pittsburgh |
Stewart B.W.,University of Pittsburgh |
Hedin R.S.,Hedin Environmental |
And 2 more authors.
Applied Geochemistry | Year: 2013
Unplugged abandoned oil and gas wells in the Appalachian region can serve as conduits for the movement of waters impacted by fossil fuel extraction. Strontium isotope and geochemical analysis indicate that artesian discharges of water with high total dissolved solids (TDS) from a series of gas wells in western Pennsylvania result from the infiltration of acidic, low Fe (Fe < 10 mg/L) coal mine drainage (AMD) into shallow, siderite (iron carbonate)-cemented sandstone aquifers. The acidity from the AMD promotes dissolution of the carbonate, and metal- and sulfate-contaminated waters rise to the surface through compromised abandoned gas well casings. Strontium isotope mixing models suggest that neither upward migration of oil and gas brines from Devonian reservoirs associated with the wells nor dissolution of abundant nodular siderite present in the mine spoil through which recharge water percolates contribute significantly to the artesian gas well discharges. Natural Sr isotope composition can be a sensitive tool in the characterization of complex groundwater interactions and can be used to distinguish between inputs from deep and shallow contamination sources, as well as between groundwater and mineralogically similar but stratigraphically distinct rock units. This is of particular relevance to regions such as the Appalachian Basin, where a legacy of coal, oil and gas exploration is coupled with ongoing and future natural gas drilling into deep reservoirs. © 2013 Elsevier Ltd.