Membrane separation technology delivers onsite water treatment, recycling
By Katie Mazerov, contributing editor
National Oilwell Varco (NOV) FluidControl has introduced a mobile water-treatment system for hydraulic fracturing operations that uses a membrane separation technology relying on vibration rather than flow-rate technologies or chemicals.
The AQUA-VES Mobile Water-Treatment System, recently deployed in West Texas, removes all suspended solids, oil, grease, bacteria and oxidized iron from the water, breaking it down to a brine that can be reused for fracturing, said Drue Ann Whittecar, business development manager, NOV Water Services. The system can process between 2,500 bbls and 10,000 bbls of liquid waste a day. “After it is processed, the water is very clear and clean, opening up opportunities for operators to source less water on the front side of a fracturing operation and dispose less water on the backside,” she said.
The system, developed by NOV in conjunction with a third party, is transported on a 53-ft trailer and includes a pump skid and two membrane towers that remove suspended solids, total petroleum hydrocarbons (TPH), bacteria and oxidized metals from water. A combination of micro- and nano-filtration are used to extract contamination from water. The design allows the membrane to remain clean, allowing for unobstructed filtration of the flow-through water, Ms Whittecar explained. The system can accommodate a wide range of membrane sizes, from micro-filters to reverse osmosis, making it applicable for a variety of operating environments.
“Water management is not a one-size-fits-all situation but varies by shale play,” she said. “Water that comes into the system will be different in every play, as will the water requirements for drilling and completions operations. The AQUA-VES system is particularly suited to West Texas, where it is difficult to source water due to demand from the local population. We also believe AQUA-VES will be a good fit for cleaning solids out of salt water-based mud in the Bakken play, where operators need brine for hydraulic fracturing, and in the Marcellus, where used water must be shipped to Ohio for disposal.”
The self-cleaning membrane technology requires minimal pre-treatment due to the high shearing energy at the membrane surface and near the pores. It delivers throughput rates five to 15 times higher than conventional units, and uses less energy than cross-flow filtration systems that require high flow rates to keep the filters clean, she noted. Membrane cleaning can be done on the surface, without the unit being disassembled. The Teflon coating is resistant to acids, solvents and other cleaning compounds.
The company is building three more systems for deployment to shale plays and is looking at developing other applications as well, including one for offshore use, Ms Whittecar added. Regulations allow salt water to be discharged, but any water containing solids must be transported back to shore for disposal.
AQUA-VES is a trademarked term of NOV.
