Efficiency, whether defined in terms of capital or operational attributes, can be a critical success
factor to owners in capital project delivery. Alternate delivery methods are often determinant in
establishing the most efficient configuration for water treatment facilities. Such is the case with
the Twin Oaks Valley Water Treatment Plant where San Diego County Water Authority chose to
implement a Design-Build-Operate (DBO) delivery method for its new 100-mgd water treatment
plant. Because of the DBO process, decisions have been made on a true net present value basis
driving many decisions on the project to very high levels of sustainable, efficient, and least
impact practices including:
most cost-effective approach based on use of low-pressure membrane treatment technology
compared to conventional water treatment;
zero liquids discharge from the site by neutralizing and recycling backwash streams;
reducing consumables over the life of the project, not just during construction;
minimized footprints to reduce impact to site and construction material requirements;
substantially reduced chemical consumption and residuals handling requirements by
eliminating coagulant;
minimized environmental impacts with early site work packages to avoid impact to
wildlife habitat during nesting season;
worked win-win agreement with neighboring water district to eliminate 10,000 truck trips
for fill required onsite; and,
designed facilities to maximize use of site topography with campus style facility.
As a result, the facility requires less than 11 acres for all elements, including clearwells, of a 100-
mgd plant employing state-of-the-art treatment technologies. The plant incorporates low
pressure ultrafiltration (UF) membrane filtration, ozonation/advanced oxidation processes, and
biological activated carbon contactors. The plant utilizes high-rate residuals treatment processes
and a unique approach for neutralizing spent chemical cleaning solutions to completely recover
all waste streams generated in the main process stream. This effort, alone, saves over 5 mgd of
potentially lost water resource and results in a process that is over 99.99 percent water efficient.
All aspects of the delivery process - design, build, and operate - have been incorporated into
an integrated approach that has resulted in the highest levels of efficiency and sustainability for
the project with the least impact to the environment and community. Includes table, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 1.8 MB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 47 |
| Published : | 06/01/2007 |
