For the Los Angeles Department of Water and Power
(LADWP), membrane filtration offered the best option for
treating water from the city's open reservoirs because the
technology produced superior water quality, used minimal chemicals,
required only a small footprint, and could be easily automated.
Because of the lack of information about the comparative
performance of major membrane filtration systems on high-quality
open reservoir water, LADWP decided to pilot-test four membrane
systems, two microfiltration and two ultrafiltration. In undertaking
this research, the utility hoped to obtain practical, objective
data that would help develop design criteria for full-scale installations
with capacities of 6-10 mgd (23-38 ML/d).
The membrane comparison considered a range of factors
including flux, rate of fouling, and frequency and efficiency of
chemical cleaning. Although all four systems tested produced
similar quality water when the manufacturers' operating criteria
were followed, the pilot testing did uncover important differences
in flux, water recovery, and system maintenance. The key operating
factors used in the city's final selection were the winning
system's higher flux of 80 gfd (136 L/m2/h), its ability to withstand
feedwater pressure of up to 60 psi (414 kPa), its relatively higher
water recovery, and its resistance to a wide range of free chlorine
concentrations.
By evaluating the performance of the membrane systems at
pilot-scale using reservoir water, LADWP was able to pinpoint
the different membranes' potential strengths and shortcomings
for the project's specific requirements. In addition, the pilot testing
proved valuable because it provided essential operational
information that could be used in the design of the full-scale
installations. Includes 10 references, tables, figures.
| Edition : | Vol. 94 - No. 12 |
| File Size : | 1
file
, 510 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 8 |
| Published : | 12/01/2002 |
