Massachusetts-based Oasys Water has commissioned its first membrane brine concentrator (MBC) in West Texas’ Permian Basin oilfield. The 100 bbl/d unit employs Oasys’ proprietary engineered osmosis (EO) technology to concentrate produced water with a TDS averaging 70,000 mg/L up to 230,000 mg/L, while yielding a permeate with a TDS less than 300 mg/L.
EO is a variation of the forward osmosis (FO) process which uses an ammonia/carbon dioxide draw solution to provide the osmotic gradient necessary to drive the permeation of fresh water across a thin-film composite, spiral-wound membrane. The draw solution is then heated to separate the draw solution and produce fresh product water.
According to Oasys’ Lisa Marchewka, the MBC system’s operating costs are about $0.60/bbl, including energy, while a conventional pretreatment system treats feedwater at a cost of approximately $1/bbl. “The MBC is being operated by Select Energy Services, our partner in the Permian Basin. If the unit continues to perform as it has, Select intends to increase its capacity to 4,000 bbl/d,” she said.