evaluation of unconventional natural gas development
DESCRIPTION
Evaluation of Unconventional Natural Gas Development. Potential Impacts to Aquatic Environments. Kathleen Patnode – PAFO . Resource Concerns. WATER QUANTITIY & QUALITY. TNC Pennsylvania Chapter 2010. WATER QUANTITY. Demand 5 to 7 million gallons per well from small streams by truck - PowerPoint PPT PresentationTRANSCRIPT
Evaluation of Unconventional Natural Gas
DevelopmentPotential Impacts to
Aquatic Environments
Kathleen Patnode – PAFO
TNC Pennsylvania Chapter 2010
Resource ConcernsWATER QUANTITIY & QUALITY
Demand • 5 to 7 million gallons per well• from small streams by truck• from rivers by pipeline• need reduced by recycling of used water
Water withdrawal regulations• varies between states • varies between and within river basins
WATER QUANTITY
Chemicals added to Frac Water • Acids• Friction Reducers• Surfactants• Gelling Agent• Scale Inhibitor• pH Adjusting Agent• Oxygen Scavenger• Breaker• Crosslinkers• Iron Control• Corrosion Inhibitor• Antibacterial agent
WATER QUALITY
Wastewater Issues
Flowback Water – hydraulic fracturing fluid that flows back to surface• up to ≈ 70 % flows to surface• most recovered in first 1 to 2 weeks• TDS increases up to 200,000 ppm• frac chemicals, trace elements & NORM
Characterizing the Waste
Wastewater IssuesFlowback Water Management Options • Deep Well Injection• Discharge to POTWs• Direct Reuse for Fracking• Treatment for Reuse
Reuse Pressure to:• reduce stream and
river withdrawal • eliminate
wastewater pass-through at POTWs
Contamination of water sources
No backflow preventers installed
Contaminated water and invasive species in vac trucks can discharge into water source (well, tank, lake, stream)
Brine Treatment at Conventional Treatment Plants
• VOCs – blown off• Oil & Grease,
removed• Metals, removed• Does NOT treat
TDS salts or NORM
• TDS in = TDS out
Reusing WastewaterTreatment for Reuse • 5-7 acre impoundments for mixing• impoundments provide reuse water to multiple wells • ~2000 truck loads of wastewater on rural roads• use of reuse lines from impoundments to local wells • high risk of truck spills and waste line breaks• spills are not being reported to NRC
Potential Impacts to Natural ResourcesImpact Trust Resource
Ground water contamination public lands, water wells, T&E aquatic species, aquatic biota
Surface water contamination public lands, T&E aquatic species, aquatic biota
Flowback water disposal in evaporation ponds (COWDFs)
birds, breeding amphibians
Proppant (resin-coated sand) spills bird species(sand ingested as grit, effects unknown)
Water depletions T&E aquatic species, aquatic biota
Potential Contamination Pathways
• Well Blowouts
• Groundwater contamination• Inadequate well cementing
• Surface water contamination• Frac flowback spills• Leaking or overflowing open water impoundments• Insufficient wastewater treatment
Water quality violations: conductivity, osmotic pressure, barium, strontium, chloride, aluminum
Mortality:fish, aquatic invertebrates, amphibians
Documented Impacts to FWS Trust ResourcesFrac Flowback SpillAcorn Creek, KY in 2007
• Threatened Blackside dace• Frac flowback spilled into creek• Lowered pH from 7.5 to 5.6• Increased conductivity
• 100 to 35,000 uS/cm• Fish & aquatic invertebrate mortality
Source: Anthony Velasco, Environmental Contaminants Specialist, USFWS, KY
UNAUTHORIZED TAKE
LACK OF COORDINATION WITHOUT FEDERAL NEXUS
EROSION AND SEDIMENTATION
Extensive disturbanceInsufficient E&S controlsMultiple creek crossingsDrilling mud releases
Objective to address key science issues and data gaps
• Geological framework• Changes in water availability (groundwater and surface water)• Changes in water quality (groundwater and surface water)• Changes in air quality (stray gas and dust)• Induced seismicity• Changes in landscape and habitat condition• Effects of these changes on
• biological resources• human health• ecosystem services
Federal Interagency Team
Mussel Interagency Team (FWS, USGS, EPA)
-determine no effect concentrations for ions in flowback water-work with state to implement protective permit limits-establish injury levels for spill NRDA
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
Dow...
Cond
uctiv
ity (u
S/cm
)
Aug Sept Oct Nov Dec Jan Feb Mar Apr
Best Management Practices – Water Quality
• Development & use of “green” chemicals
• Closed loop drilling & fracturing• No pits & reuse of frac water
• Treatment and reuse of frac water
• Development & use of dry-frac process• Liquid CO2
• Explosives
• Development of spill contingency plans• public lands / easements• Other areas with sensitive species