Pre-ozone prior to microfiltration membranes was operated at the pilot scale to evaluate the benefits of
enhanced organic carbon removal and advanced oxidation of Tuolumne River water in California. The pilot
study was conducted to support the design and construction of a new treatment plant for the Turlock
Irrigation District, an irrigation and power company in California. It was anticipated that pre-ozone in
conjunction with alum would increase iron, manganese, color, turbidity, and organic carbon removal and
improve membrane performance compared to coagulant addition alone. As a result of improved organic
carbon removal, it was anticipated that a decrease in disinfection byproduct (DBP) formation would be
observed. Results from the pilot evaluation, however, showed that although iron, manganese, and turbidity
levels were significantly decreased through membrane filtration, the reduction was consistent with and
without pre-ozone. Increased reduction in the UV254 and total organic carbon (TOC) concentrations was
observed in conjunction with a decrease in the total trihalomethane (THM) and haloacetic acid (HAA)
formation for pre-ozone and alum addition compared to membrane treatment alone or with post-ozone
treatment. Oxidation with ozone resulted in a reduction in organic carbon, a DBP precursor, and the
chlorine dose necessary to provide adequate disinfection residual. Combined, these two factors reduced the
total THM and HAA formed during 7-day simulated distribution system (SDS) evaluations. Impact of preozone
on membrane system performance was membrane system dependent. Pretreatment with pre-ozone
and alum combined and alum only were found to enhance membrane performance by significantly decreasing
the rate of membrane fouling for one system, to increase the fouling rate for another membrane system, and
to result in similar fouling for the third system as observed without chemical addition. Issues with solids
carryover due to poor sludge drainage was likely the cause of some of the membrane fouling for one of the
membrane systems. However, one membrane system did not appear to be impacted by the solids carryover
and continued to show improved membrane performance during this period. Based on these piloting results,
the recommended treatment train for the new water treatment plant for Turlock Irrigation District includes
pre-ozone, alum coagulation, flocculation, plate settlers, microfiltration membranes, and post-chlorination. Includes 20 references, tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 3.1 MB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 16 |
| Published : | 11/01/2007 |
