(101a) Advanced Treatment of Shale Gas Frac Water to Produce NPDES Quality Water

Advanced Treatment
of Shale Gas Frac Water to Produce NPDES Quality
Water

Bob
Dahlin, Bill Chatterton, Behrang
Pakzadeh, Austin Vaillancourt

Southern
Research Institute, 5201 International Drive, Durham, NC, 27712

Natural gas extraction by fracking produces
two types of wastewater that must be managed: 
1) Flowback water is produced when the fracking is complete and pressure is released.  Approximately 10% to 30% of the water used
for fracking flows out of the well over a period of
about ten days, and 2) Produced water, a mixture of water that was trapped
underground with the gas deposit and frac water,
flows out of the well with the natural gas over the several years life of the
well at a rate of 100 to 1,300 gallons per day.

All wastewaters produced by drilling and fracking
are regulated by the Clean Water Act (CWA) and are subject to the
technology-based regulations (40 CFR Part 435, Subpart C) which apply to
onshore facilities ?engaged in the production, field exploration, drilling,
well completion and well treatment in the oil and gas extraction
industry.?  The effluent guidelines at 40
CFR 435, Subpart C establish best practicable control technology currently
available (BPT) requirements for onshore facilities and prohibits the discharge
of waste water pollutants into navigable waters from any source associated with
production, field exploration, drilling, well completion or well
treatment. 

Southern Research Institute, with
project partners M2 Water Treatment, Inc. and BKT United, has been awarded a
contract by RPSEA (Research Partnership to Secure Energy for America) to develop
an innovative, cost-effective, and robust approach for treatment of shale gas frac water to produce National Pollution Discharge
Elimination System (NPDES) quality water for discharge and/or reuse. The approach comprises optimizing the
combination of four technologies, two for frac water
treatment and two for treatment and disposal of residues (high solid slurry and
membrane concentrate) from the frac water
treatment.  The frac
water treatment technologies are  magnetic ballast clarification (MBC) for
removal of total suspended solids (TSS), metals, and  naturally occurring radioactive materials
(NORMs) , and vortex-generating and nano filtration membranes,
for removal of TSS and/or total dissolved solids (TDS).  The residue treatment/disposal technologies
are hydrogel adsorbent for metals, NORMs, and trace element removal, and
precipitation, solidification and stabilization. 

The project began in May of 2013 and
is anticipated to continue for a period of 24 months.  The project tasks include bench-scale
simulation, onsite field research/testing, and a feasibility analysis.  The objective of the
bench-scale simulations is to develop a method to allow for a quick evaluation
as to whether waters from a specific well are amenable to treatment with MBC,
membranes, and hydrogel media or precipitation/solidification/stabilization.  The objective of the onsite field
research/testing is to provide a linkage from the bench-scale simulations to
what can be expected in the field.  The
objective of the feasibility analysis is to bring together the technical,
economic and environmental data to assess the advantages and disadvantages of the
proposed integrations compared to conventional technologies.  If selected, Southern Research plans to present
the detailed analysis and results from the bench-scale testing and any
available preliminary data from the onsite field testing.