Membrane technology is increasingly used to treat water sources in the oil and gas industry. Nano-filtration membranes are used to remove sulphate from seawater on sulphate-reducing platforms. This prevents barium and strontium sulphate deposition and sulphate-reducing bacteria colonising the wellhead, and producing toxic hydrogen sulphide and corrosive sulphuric acid.
The development of shale gas and coal bed methane extraction has resulted in an increase in the use of membrane technology to treat produced water to an environmental profile where it can be discharged to surface watercourses or sent for aquifer recharge or site reuse.
The water treatment systems are usually a combination of settling, filtration and reverse osmosis. While the permeate quality of the RO water is high, the membranes themselves are often subject to rapid fouling due to the nature of the produced water which has a high fouling propensity.
Genesys International has launched GENAIRCLEAN - a new RO membrane-cleaning programme incorporating microbubbles.
After a three-year UK Government-funded research project, four papers were presented recently at the International Desalination Association World Congress in Tianjin. Genesys managing director Steve Chesters put forward GENAIRCLEAN, a technique that combines multiple cleaning mechanisms to improve the removal of deposits from RO and NF membranes. According to senior research chemist and process inventor Max Fazel, the cleaning process is supplemented by introducing air into the chemical cleaning solution using a microbubble generator.
"The pulsing stream of 5-500-micron microbubbles works in combination with our chemical cleaners to mechanically disrupt foulants on the membrane surface, which significantly shortens cleaning times," he said.
Genesys made a full commercial launch of the process at Aquatech Amsterdam in November 2013, where it picked up an innovation award.
"After extensive testing in both laboratory and the field we have presented papers on an innovative method to improve membrane cleaning efficiency; reducing cleaning time with lower chemical use," Chesters said. "This new system can help prolong membrane life and reduce cleaning frequency with no additional energy requirement."