AWWA SP250163

This paper concludes the following: 1) Energy and particle removal efficiencies were higher with the ultrafiltration (UF) membrane than with the microfiltration (MF) membrane. The UF membrane unit was operated at a filtrate flow rate of almost 9 gpm after more than 500 days of testing, achieving filtrate particle densities in the size range between 5 and 60 microns which were comparable to the "blank" laboratory water. 2) Average membrane flux of about 90 gfd can be expected from the UF membrane tested with well water. At this flux rate, capital costs are estimated at less than $1.00 per gallon per day to add membrane filtration at a facility such as Cabot well. 3) Operating and maintenance cost estimates derived from the test unit data were $0.16 per 1000 gallons. 4) Periodic backwashing with hypochlorite at doses of up to 240 mg/L (as chlorine) proved effective in restoring flux of the UF membrane, and was enhanced by a "rest" period between chemical addition and backwashing. Daily addition of hypochlorite (at less than 50 mg/L as chlorine) in addition to twice daily backwashing has maintained a higher and more consistent flux and controlled, but did not eliminate, heterotrophic bacteria in the filtrate.

Product Details

Published:

01/01/1991

ISBN(s):

0898675758

Number of Pages:

23

File Size:

1 file , 800 KB