Nov 26 2008
Heat and electricity developer NingBo Jiufen Co-gen is using DOW™ Ultrafiltration membranes as the sole pretreatment in its reverse osmosis water treatment process. This particular customer faced construction and economic constraints, and the ultrafiltration (UF) membranes helped them manage the site's steady supply of steam and hot water, resulting in optimal flux and high recovery.
The site handles the generation, installation, and repair of electrical services for the NingBo province in China. The site also maintains a steady supply of source water through the nearby XiePu River, which is high in total suspended solids with temperature fluctuation and seawater intrusion that increases the impurity level in the river. Nevertheless, the DOW Ultrafiltration membranes are able to overcome these challenges and demonstrate solid performance with an average product water turbidity of 0.1 Nephelometric Turbidity Unit (NTU) and silt density index (SDI) of less than two.
"One of the biggest challenges that our customers face is finding an economical solution that is able to handle variable swings in dissolved solids and feed water conditions while removing turbidity to a very low level without the addition of pretreatment prior to the utlrafiltration system," said Christina Fang, area commerical development manager, Dow Water Solutions. "Our ultrafiltration modules provide steady performance making the membranes a reliable, economical and efficient solution for the NingBo site."
The UF membranes have been in operation since August 2005 without chemically-enhanced backwash (CEB) and with only periodic clean in place (CIP) to restore or stabilize the transmembrane pressure (TMP). Overall, the reverse osmosis system has only required four chemical cleanings over a two-year period.