디잴리테크(Desalitech)사는 ReFlex™ 역삼투 시스템 과정을 통해 텍사스 엘파소(El Paso)에 위치한 케이 베일리 허치슨(KBH, Kay Bailey Hutchison) 담수화 플랜트에 높은 물 회수율을 기록하는 성공적인 지하수 정화 공정을 구축했다. 발표에 따르면 텍사스대학교의 아일랜드 담수화 시스템 센터(CIDS, Center for Inland Desalination Systems)에서 8개월의 기간에 걸쳐 실증시험이 완료되었다.

 

실증시험의 성공까지는 기존 역삼투 공정에서 가능한 회수율을 초과해 실리카 및 스케일링이 없는 염수 담수화 과정을 통해 94%의 회수율을 보였다.

 

 

 

Desalitech announced today that its ReFlex reverse osmosis (RO) process successfully purified groundwater at the Kay Bailey Hutchison (KBH) Desalination plant in El Paso, Texas, at record high water recovery rates. The announcement was made upon completion of tests conducted by the University of Texas’ Center for Inland Desalination Systems (CIDS) over a period of eight months. The tests successfully demonstrated brackish water desalination operation at 94% recovery without silica (and other) scaling, far exceeding the recovery rates possible with traditional RO technology. The demonstration establishes a new standard for water efficiency in reverse osmosis processes with significant global financial and environmental implications.

 

Silica is a natural contaminant present in ground water around the world that is notorious for precipitating in desalination and other membrane processes, producing a dense coating that is nearly impossible to remove. Accordingly, the water recovery rate at which a reverse osmosis system can operate is limited by the presence of silica and other sparingly soluble constituents. Low-recovery operation results in a high-volume waste stream that requires difficult and expensive treatment or disposal. The prospect of sustainable inland RO operation at recovery rates that exceed the saturation concentrations of these salts represents a technological breakthrough for industrial and municipal water purification.

 

The 27.5 million gallon per day KBH plant was commissioned in 2007 to supply drinking water to El Paso. The plant assures public water supply despite drought conditions, emergency situations, population growth and salt water intrusion into fresh water aquifers. The plant pumps groundwater from an onsite nearby wellfield to treatment works that include sand strainers, cartridge filters and reverse osmosis equipment. The plant is currently operating at 82.5% recovery, limited by the traditional multi-stage RO design along with the high silica concentrations, resulting in a wastewater stream that is sent to disposal wells.

 

CIDS installed a mobile containerized Desalitech RO pilot unit at the KBH plant in June of 2015. The pilot unit was equipped with standard reverse osmosis membranes, pumps and other components, which operated at typical membrane flux and crossflow rates. Recovery rates above 90% were sustained for days of continuous testing. The highest recovery achieved without scale formation was 94%, corresponding to silica supersaturation of 273%. For context, traditional reverse osmosis and distillation systems are generally limited to a maximum of 100% silica saturation. Detailed results of the tests are expected to be published by CIDS.

 

[출처 = Water World / 2016년 4월 13일]