1. Unconventional Gas: Shale Gas Shale Gas  Unconventional gas (hydrocarbons) found in subsurface shale formations  Replacement to coal, oil, and natural gas  Clean burning  1,744 trillion cubic feet (tcf) of shale gas estimated reserves 110 year supply… R.A. Kerr, 2010 and D.O.E., 2009 Shale Gas Basins in the Continental U.S. U.S. Fuel Energy Consumption 2007 Energy dependence in the U.S.  Surge in exploration of shale gas in North America Energy dependence in the U.S.  Surge in exploration of shale gas in North America

2. Gas from Shale Rock? Two phase process  Horizontally Drill  Hydraulic fracturing (frac) Both processes are water intensive! (>10 million gallons) Both processes are water intensive! (>10 million gallons) Generating large volumes of wastewater as flowback Generating large volumes of wastewater as flowback

3. Typical O&G Operation External Source Water WasteStream Waste Stream OPEN SYSYTEM WASTE FRAC TANKS Prepare fracture fluids FRAC PUMPS Pressurize fracture mixture GAS WELL HEAD Horizontal drill and frac DRILL & FRAC WASTE RESERVOIR Store drilling and fracturing waste

4. What is Fracturing? Hydraulic fracturing of shale rock  Pressurize hydraulic mixture (up to 1,000 psi)  Up to 5 fractures per day/crew  2-6 million gallons of water per well

5. Fluid Management  Fluid Management Source water  Local or regional freshwater Drill/Frac wastewater  Disposal  Deep well injection  Costly  Environmentally disruptive  Recycling  Typically settle and decant  Only 50-60% water recovery! (at times <20%)

6. Oil & Gas Exploration and Production Turning Waste Streams Into Resources One industry’s waste… - Appropriate Treatment -Public Perception -Resource Management Is another's high value water resource…

7. Oil & Gas Exploration and Production Potential Beneficial Reuses Livestock Watering Irrigation Industry Stream Augmentation Internal Reuse

8. Oil & Gas Exploration and Production Is Adequate & Effective Treatment Possible?  Gelling agents, friction reducers, surfactants  10,000 to 30,000 ppm TDS  1,000 to 5,000 mg/L organic constituents  Reduced conditions  1 to 6 million gallons of waste produced/well Addressing tough industrial streams  Robust on-site treatment  Mobile and modular construction  Inexpensive waste stream reduction  Flexible under variable influent compositions  Treat high TDS waste steams

9. Potential Processes for Treatment of O&G Wastewater

10. Station 4: Oil and Gas Production Wastewater Pretreatment Objective Evaluate potential pretreatment of oilfield wastewater (a mixture of produced water and frac flowback wastewater) Focus on maximizing wastewater oxidation and subsequent turbidity removal through coagulation/flocculation

11. Station 4: Oil and Gas Production Wastewater Pretreatment O XIDATION P ROTOCOL Investigate hydrogen peroxide oxidation of oil and grease, organic matter, and metals (manganese). Tests conducted at ambient pH and temperature of approximately ~20 °C. Hydrogen peroxide (35% and SG of 1.1) will be dosed at various concentrations (0.5 to 3.0 g/L) into 1L jars. Oxidation-reduction potential (ORP), manganese concentration, and pH should be measured after 15 minutes of reaction time.

12. Station 4: Oil and Gas Production Wastewater Pretreatment C OAGULATION PROTOCOL Aluminum or iron salts will be added after sample oxidation. Aluminum (10-60 mg/L) from Al 2 (SO 4 ) 3 (alum), AlCl 3 (aluminum chloride), and iron (10-60 mg/L) from a solution of ferric chloride (FeCl 3 ) are the chosen coagulants. Turbidity and pH should be measured in the raw wastewater sample and each of the settled jars. Samples for Mn, COD, alkalinity, and hardness analysis should be taken from the jars showing the greatest turbidity removal.

13. Station 4: Oil and Gas Production Wastewater Pretreatment E LECTROCOAGULATION PROTOCOL Aluminum or iron electrodes will be used after sample oxidation. Doses will be controlled through current density (Amp./cm 2 ) Flocculation (jar tester) following electrocoagulation Turbidity and pH should be measured in the raw wastewater sample and each of the settled jars. Samples for Mn, COD, alkalinity, and hardness analysis should be taken from the jars showing the greatest turbidity removal.