1 A LOW-COST, GREEN TECHNOLOGY FOR ACID MINE DRAINAGE TREATMENT USING A WATER TREATMENT BY-PRODUCT: A PRELIMINARY STUDY Louis Ackah 1, Rajesh Guru 1, Meisam Peiravi 1 and Guilherme Cordeiro 1 Faculty Advisers: Manoj Mohanty 1 and Xingmao “Samuel” Ma 2 1 Department of Mining and Mineral Resources, Southern Illinois University 2 Zachry Department of Civil Engineering, Texas A& M University Illinois Mining Institute (IMI) Annual Meeting 8/26/2015 Presented by: Louis Ackah

OUTLINE  Background  Study Area  Problem Identification  Objectives  Methodology  Preliminary observations  Conclusions 2

3 BACKGROUND  Acid mine drainage (AMD) mostly from abandoned mines poses serious environmental and health problems.  AMD results when exposed pyrite (FeS2) reacts with air and water. FeS 2 + 6Fe H 2 O 7Fe 2+ + S 2 O H +  It is characterized by a low pH-value and high levels of sulfate and metals.  Metals are non biodegradable, they accumulate in the environment.  Some metals are carcinogenic, mutagenic, teratogenic and endocrine disruptors while others cause neurological and behavioral changes especially in children (Ali et al., 2013).

4 BACKGROUND (contd)  Different physical and chemical methods used for this purpose suffer from serious limitations like: high cost, intensive labor, alteration of soil properties and disturbance of soil native microflora.  Over 12,000 miles of rivers and streams, and 285 sq. miles of lakes/reservoirs are adversely impacted by AMD.

5 STUDY AREA  Location: Tab-Simco is an abandoned coal mine located in the Illinois Basin ≈ 5 miles southeast of Carbondale, Illinois, USA.  Geology: Located on a dissected, low plateau underlain by coal-bearing Pennsylvanian System.  U/G Mining: 1890 to1955. mined – the 8.2 ft thick Murphysboro Coal and the overlying discontinuous 4.9 ft thick Mt. Rorah Coal.  Surface Mining: during the 1960’s and 1970’s in a horseshoe-shaped pattern Location and schematic diagram of Tab- simco site bioreactor system.

6 PROBLEM IDENTIFICATION  The old underground workings are partially flooded with seasonal fluctuations  Contains million gallons of acidic, metal-laden water (Smith, 2004).  AMD water impacted soil of about 9-acre area was devoid of vegetation and covered with acid salts.  Sycamore Creek: impacted with acidic water and metal precipitates.

Water Treatment Residuals( WTR)  WTR are any solid, semisolid, or liquid residue generated (as product) during drinking water treatment processes.  Challenge: finding an economical and efficient way to get rid of the residual solids that are filtered out.  Current practical disposal/reuse options: Direct land application Stabilization Composting or pelletizing Stream discharge* 7 Al based WTR Fe based WTRCa based WTR Potential for environmental remediation  adsorbs heavy metals irreversibly.  readily available for free of cost

Physico-chemical Characterization of WTRs 8 Chemical/Physical Property AL- WTR Ca- WTR Fe- WTR pH Electrical conductivity (ms/cm) Particle density (g/cm 3 ) Sample FeCaPMgTiAlNaKS Percentage % Al-WTR > Ca-WTR < Fe-WTR Sample CuPbZnCdNiCoMnAsCr ppb (µg/kg) Al-WTR Ca-WTR Fe-WTR Sample SrLaZrBaScCeGaSnY ppb (µg/kg) Al-WTR Ca-WTR < Fe-WTR Heavy metals content of the dried sludge measured using ICP-MS after extraction with Aqua-regia

9  To investigate the metal immobilization capability of locally generated water treatment residue (WTR) for the treatment of AMD water. OBJECTIVES  Optimize phytoremediation models for passive treatment of AMD and AMD impacted soil, and erosion control of the soil.

METHODOLOGY: Plug Filter Study (Metal adsorption)  Batch adsorption tests were performed with various Al, Ca & Fe WTR treatment mixes to evaluate metal adsorption capacities.  Continuous flow filter was designed with the WTR as media to treat AMD water. Metal reduction (adsorption capacity) pH increase Hydraulic conductivity 10

METHODOLOGY: Proposed phytoextraction/immobilization Metal uptake from AMD Water metal concentration change effects of planting density metal translocation in the plant. 11 Erosion and Metal Leaching Control by WTR and Vetiver/pokeweed optimum residuals mix for plant growth erosion control, adsorption and long- term immobilization of metal ions WTR-AMD soil incubation set up before column study. Two hyperaccumulators: Vetiver grass (Vetiveria zizaniodes L.) Poke weed (Phytolaccae americana) highly tolerant to very acidic, alkaline, saline, and sodic soil conditions.

PRELIMINARY OBSERVATIONS (SOIL)  Incubation test results shows significant increase in soil pH and electrical conductivity 12

PRELIMINARY OBSERVATIONS (contd)  From the Batch test it observed that all the WTRs have various degrees of metal adsorption capabilities. 13 Treat- ment Al conc. (ppm) % Removal Fe conc. (ppm) % Removal Mn conc. (ppm) % Removal Al-WTR % Fe-WTR498% Ca-WTR0100% Al:Fe-WTR % Al:Ca-WTR7.596% Control  Hydraulic conductivity of the Ca & Fe based WTRs are lower than the Al-based WTR.

PRELIMINARY OBSERVATIONS (contd)  Hydraulic conductivity of the Ca & Fe based WTRs is lower than the Al-based WTR.  In a continuous flow test at 2 flow rates, there was observed loss in filtration rate of the media (plugging) at the higher flow rate.  This major operational problem is due to the formation of precipitates and coating of available carbonate minerals. 14

PRELIMINARY OBSERVATIONS (contd) 15 Initial Conc. = 410 mg/l

PRELIMINARY OBSERVATIONS (contd) 16 Initial Conc. = mg/l Initial Conc. = 950 mg/l

17 PRELIMINARY CONCLUSIONS  Soil incubation tests shows WTR neutralizing capabilities.  The analysis of WTRs shows they can be valuable material to facilitate re-vegetation of degraded land/soil.  The preliminary study shows that this inexpensive and environmentally friendly approach can effectively treat AMD- impacted water in a continuous flow fashion.

18 Reference  Ali, H., Khan, E., & Sajad, M. A. (2013). Phytoremediation of heavy metals—concepts and applications. Chemosphere, 91(7),  Behum, P. T., Lefticariu, L., Walter, E., & Kiser, R. Passive Treatment of Coal-mine Drainage by a Sulfate-reducing Bioreactor in the Illinois Coal Basin.

19 THANK YOU