civil and environmental engineering 

# Sustainable Water Management for 

# Marcellus Shale Development Radisav D. Vidic, Ph.D., PE Department of Civil and Environmental Engineering



### Swanson School of Engineering University of Pittsburgh Pittsburgh, PA 15261civil and environmental engineering 

# Shale Gas Basinscivil and environmental engineering 

# Hydrofracturingcivil and environmental engineering 

# Permitted Gas Wells in PA
Permits through February 2010civil and environmental engineering 

# Water Supply Issues • Need 1 to 8 Million gallons of water per well for hydrofracturing • Surface Water Withdrawals

– Concerns about depletion of water resources, especially in drought years
– Impacts to aquatic life
– Negative publicity
– Ability to get withdrawals approved
– Don’t really need high quality water, but consistent quality is important 

### • Transportation of water

– 1 MG = 200 trucks
– Cost can be significant ($0.1/bbl to $2/bbl) 

### • Water storage on sitecivil and environmental engineering



# Fracing Fluidscivil and environmental engineering 

# Fracture Fluid Composition Additive type Main Compound Purpose Diluted acid (15%) Hydrochloric or Muriatic Dissolve minerals and initiates cracks in rock Biocide Glutaraldehyde Bacterial control Corrosion inhibitor N,n-dimethyl formamide Prevents corrosion Breaker Ammonium persulfate Delays breakdown of gel polymers Crosslinker Borate salts Maintains fluid viscosity at high temperature Friction reducers Polyacrylamide Minimize friction between the fluid and the pipe Mineral oil Gel Guar gum or

hydroxyethyl cellulose Thickens water to suspend the

sandcivil and environmental engineering 

# Fracture Fluid Composition Additive type Main Compound Purpose Iron control Citric acid Prevent precipitation of metal oxides Oxygen scavenger Ammonium bisulfite Remove oxygen form fluid to reduce pipe corrosion pH adjustment Potassium or sodium

carbonate Maintains effectiveness of other

compounds (e.g., crosslinker) Proppant Silica quartz sand Keeps fractures open Scale inhibitor Ethylene glycol Reduce deposition on pipe Surfactant Isopropanol Increase viscosity of fluidcivil and environmental engineering 

# Wastewater Issues • Frac Flowback Water

– High flows for short duration
– 10 to 40% offrac fluid recovered
– Most recovered in first 1 to 2 weeks
– TDS quickly climbs to 30,000 mg/L up to 200,000 mg/L
– Contains numerous chemical additives and naturally occurring constituents 

## • Produced Water

– Lower flows (2 to 30 bpd per well)
– Potentially very high TDS (100,000 to 300,000 mg/L)
– Continues to flow for the life of the wellcivil and environmental engineering 

# FlowbackQuantity vs. Timecivil and environmental engineering 

# FlowbackQuantity vs. Timecivil and environmental engineering 

# FlowbackWater Quality vs. Time

0 20000 40000 60000 80000 100000 120000 140000 160000 180000

1/23 1/24 1/25 1/26 1/27 1/28 1/29 1/30 1/31 2/1 2/2 2/3 2/4 2/5 2/6 2/7 2/8 2/9 2/10 2/11 2/12 2/13 2/14 2/15 2/16 Chloride mg/l Calcium mg/l Sodium mg/l Total Dissolved Solids (TDS) mg/lcivil and environmental engineering 

# Flowback Water Quality Constituent Low

(mg/L) Medium

(mg/L) High

(mg/L) Ba 2,300 3,310 4,700 Ca 5,140 14,100 31,300 Fe 11 52 134 Mg 438 938 1,630 Mn 2 5 7 Sr 1,390 2,100 6,830 Hardness (as CaCO3) 17,900 49,400 90,337 Radioactivity ND ND ND TDS 69,400 175,600 248,000civil and environmental engineering 

# Flowback Water Management • Evaporation in pits/ponds • Injection/disposal wells 

## • Discharge to POTWs • Direct reuse for fracing • Treatment for reuse or surface dischargecivil and environmental engineering



# Evaporation • Natural pond evaporation not practical

– Precipitation < Evaporation
– Poor evaporation at high salinity
– Crusting overcivil and environmental engineering



# Disposal Wells • Significant regulatory hurdles

– Impacts to water supply aquifers
– Potential for injected water to migrate to streams 

## • Limited capacities (1200 to 3000 bpd) • Substantial capital investment with uncertain life span ($1M to $2M) • Probably will only play a limited role 

## • No new injection wells have been permitted!civil and environmental engineering 

# Disposal to POTWs • POTWs use biological processes such as lagoons, trickling filters, or activated sludge • Biological systems cannot handle high salinity


## – few case studies above 35,000 mg/l • If high TDS + flow is significant portion of POTW 

## influent, this is not an option • Regulatory limitations on acceptancecivil and environmental engineering 

# Direct Reuse for Fracing • TDS is too high • Chlorides, in particular

– Corrosion concerns
– Impacts on fracing 

## • Solids, hardness, and bacteria removal • Safety, corrosion, SRB downhole concerns • Recycling of chemical additivescivil and environmental engineering 

# Treatment Options Technology Maximum Feed TDS (mg/L) Energy Use

(kWh/100 bbl) Capacitive Deionization 5,000 20 Electrodialysis reversal (EDR) 7,000 60 Electrodialysis 40,000 - Reverse osmosis 35,000 15-30 Evaporation 100,000 400 Membrane distillation 250,000 600-700 Crystallizer 300,000 1000-1300civil and environmental engineering 

# Treatment for Reuse in Fracing Operations • Reduce O&G industry needs for surface water • Reduce overall management costs

– Volume reduction
– Transportation costs
– Disposal costs 

## • Reduce potential liabilitycivil and environmental engineering 

# Current Project at the University

of Pittsburgh Implementation of a holistic solutionfor management offlowbackwater from hydraulic 

# fracturing

– develop an approach that will allow the use offlowback water from one well as a hydrofracing fluid for subsequentwells


### – appropriate treatment/separation technology, which utilizes AMD wastewater for removing toxic divalent cations from the flowback water


### – develop novel slicking agents, which will be stable in brine solutionscivil and environmental engineering 

# AMD in Pennsylavania • Pennsylvania’s single greatest source of water pollution

– Contaminated 3,000 miles of streams 

## • Often has low pH (<5) and elevated 

## levels of iron and sulfate • Can have elevated hardness 

## • TDS typically around 1,000 mg/L • May be suitable as frac water make up with little or no treatmentcivil and environmental engineering 

# AMD in Pennsylvaniacivil and environmental engineering 

# Effect of AMD Blending on Dissolved Bariumcivil and environmental engineering



# Summary • Marcellus shale development hinges on sustainable water management • Almost no disposal options forflowbackwater • Very few treatment options for disposal • Flowbackwater reuse appears to be the most effective option • AMD is potentially a suitable makeup water source in many locationscivil and environmental engineering 

# Thank you for Your Attention 

# Questions?