AWWA MTC61220

Seawater Reverse Osmosis (RO) desalination plants operating with surface open intakes requirean efficient pretreatment to meet RO system feed water quality requirements, and insure reliableoperating conditions.Several studies performed for this application present results of ultrafiltration (UF) or microfiltration(MF) as RO desalination process pretreatment obtained on several seawater resources. Theydemonstrate generally good performances in terms of permeate quality and membrane foulingcontrol. UF/MF operation limits may appear on some seawaters, and pretreatment membranesfouling can be expected while facing important seawater pollution. Moreover, membrane only issometimes a pretreatment limited to remove dissolved pollution and organics, and to insure a lowSDI value.While conventional direct filtration gives reliable results and good surface water quality, a singlestage filtration process using conventional media could not produce filtered water with a SDI valuebelow 3, 100% of the time for the treatment of seawaters with relatively high fouling (SDI valuesaveraging 15-20), leading to at least, a second filtration stage to reach this target.The objectives of this paper are to present a comparative analysis of both conventional andmembrane pretreatments upstream reverse osmosis on open intake seawater. The data used arecoming from literature reviews and from pilot studies performed on high fouling potential surfaceseawater showing periodical degradations in terms of suspended solids, SDI or hydrocarbonpollution. On one site, specific spike tests were conducted to evaluate the pre-treatment efficiencyduring pollution events. The pilot tests were performed using in parallel membrane andconventional pretreatments. Includes 21 references, tables.

Product Details

Edition:

Vol. - No.

Published:

03/01/2005

Number of Pages:

6

File Size:

1 file , 350 KB