Finished Water
master page=B-dept large
A PHOTOGRAPHIC PROFILE
The Cambria Emergency Water Supply
Plant’s feedwater, a mix of fresh groundwater,
brackish water, and secondary treated
effluent, goes through three processing steps
(from left to right): ultrafiltration to remove
solids, reverse osmosis to remove salt, and
ultraviolet/advanced oxidation.
Seaside in California’s San Luis Obispo
County, the town of Cambria (population 6,000) had faced a water shortage for
decades. The current drought exacerbated
that shortage, leading to strict Stage 3 conservation restrictions, including a 50-gpd/
resident consumption limit and an outdoor
potable-water-use ban.
In 2014, the third year of severe
drought, the Cambria Community Services
District (CCSD) voted to design and build
a brackish-water emergency water supply (EWS) facility near CCSD’s production
wells on San Simeon Creek. Gov. Jerry
Brown’s drought emergency declaration
allowed the project to move swiftly from
planning to operation, because the action
exempted such projects from the usually
lengthy environmental review process.
46 Opflow April 2015
Under the emergency Coastal Development Permit that authorized its construction and operation, the EWS is allowed to
run only when Stage 3 conservation measures are in effect.
PROJECT SPECIFICS
Project Name: Cambria Emergency Water
Supply Plant
Operator: Cambria Community Services
District
Designer/Contractor: CDM Smith, with
H2O Innovation and Trojan UV
Completion Date: Jan. 20, 2015
Water Source: Groundwater underflow
from San Simeon Creek, a seasonal stream,
augmented with 5–10 percent brackish
water and 5–10 percent treated wastewater.
The brackish water is ocean-influenced
2015 © American Water Works Association
groundwater in a “wedge” below the
lighter freshwater. The treated effluent
comes from percolation ponds. Thus, the
facility incorporates both desalination and
recycling, though its feedwater is mostly
fresh. Technology: Ultrafiltration to remove solids,
reverse osmosis to remove salt, and ultraviolet/advanced oxidation.
Project Cost: $9.77 million
Service: 450 gpm of potable water, which
is injected into the San Simeon Creek aquifer and travels for about two months to
the CCSD’s production wells. Net water for
CCSD customer use is about 300 gpm. Special Features: Combined treatment
steps achieve a 92 percent permeate recovery rate, compared with about 50 percent
for a typical seawater desalination plant.
www.awwa.org/opflow
PHOTOGRAPHS: CAMBRIA COMMUNITY SERVICES DISTRICT, CDM SMITH
COASTAL TOWN BUILDS EMERGENCY WATER SUPPLY PLANT AMID DROUGHT