The City of Sherman, Texas, currently operates a 10-million gallon per day (mgd) water
treatment plant (WTP) to treat brackish water from Lake Texoma. The plant uses
conventional treatment (flocculation/sedimentation/filtration) followed by electrodialysis
reversal (EDR) to remove dissolved solids. As a result of upcoming regulations and growing
water demands, the City of Sherman is expanding its Lake Texoma Surface WTP by 5 mgd
of finished water capacity. Microfiltration/ultrafiltration (MF/UF) followed by reverse
osmosis (RO) demineralization was selected as the best apparent technology to meet the
City's operational and water quality goals.
Treatment challenges include salinity reduction, turbidity control, total organic carbon (TOC)
reduction, elimination of objectionable tastes and odors, and pathogen removal and/or
inactivation from the surface water supply sources. Furthermore, the membrane-treated
product water will be blended and must be compatible with water from the existing supply
and treatment facilities.
A pilot study was conducted to evaluate the ability of the planned treatment to meet the
City's water quality objectives. As mentioned, planned treatment includes dual-membrane
processes, MF/UF for suspended solids and pathogen removal, followed by RO for dissolved
solids and TOC reduction. MF/UF pilots from three vendors (Ionics Norit X-flow, Pall
Microza, and Zenon ZeeWeed) were followed by two Osmonics RO pilot units. The MF/UF
vendors were required to recycle their backwash to achieve an overall system recovery of 99
percent. The product water from the MF/UF units was combined and fed to the two separate
RO units so that the performance of membranes with varying characteristics could be
compared. A scale inhibitor was used in both RO units. RO performance was compared to
manufacturer's projections. Includes tables.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 330 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 18 |
| Published : | 03/05/2003 |
