by Bob Hazard
Desalination Celebrates One-Year Anniversary
Santa Barbara mayor Cathy Murillowas able to take a well-deserved bow last week as she and Josh Haggmark, City Water Resources manager; Cathy Taylor, Water Systems manager; Randy Rowseand other civic leaders celebrated the one-year anniversary of the reopening of the City’s Charles E. Meyer Desalination Plant. All hailed the addition of desalinated water as a reliable water source added to the City’s diverse water portfolio.
Impressively, the rehabbed desalination plant is currently producing 3 million gallons of drinking water per day, or 30% of the City’s water supply, some 3,125 acre-feet per year (AFY) of “ocean to tap” water.
On hand, and available for interviews, was Gilad Cohen, CEO of IDE Americas, designer, builder, and operator of the local desal plant. IDE Americas also designed and was part of the construction team that built the new 50-million-gallons-per-day Poseidon Water desalination plant in Carlsbad, California, which produces desalinated water for San Diego County. IDE also built three desalination plants in Israel, enabling that desert country to be the only country in the Middle East to “go green.”
In 2014, Israel’s desalination programs produced roughly 35% of Israel’s drinking water. By June 2015, roughly 50% of Israel’s overall water sources came from desalination. By 2050, that percentage of desalinated water is projected to reach 70%.
The Israeli record should serve as a guidepost for coastal California, which is still clinging to an increasingly unreliable, antiquated 1950s technology of pumping vanishing northern snowpack from the High Sierras, conveyed through Lake Orville to the Sacramento Delta; then pumped through 660 miles of canals and pipelines to a complex of regulating reservoirs.
How energy-efficient is that? Should coastal urban areas deprive farmers and inland cities of needed state water?
History of Desalination
Funded jointly by the City of Santa Barbara, the Montecito Water District and the Goleta Water District, the original desalination plant, finished in 1991 at a cost of $34 million, had a capacity of 7,500 AFY of desalinated water, more than twice the production capacity of the current plant.
The Montecito Water District had an entitlement of 1,250 AFY; the Goleta Water District had an entitlement of 3,069 AFY, while the City had entitlement to 3,181 AFY. Costs were shared proportionately.
The original desalination plant operated for three months between March and June 1992, before abundant rainfall led to placing the plant into standby mode. On October 15, 1996, the California Coastal Commission issued a Coastal Development Permit to the City for permanent desalination facilities up to a maximum capacity of 10,000 AFY.
Foolishly, Montecito and Goleta failed to renew their five-year contract for water, preferring not to incur modest costs for permanent permits and standby maintenance charges.
In July 2015, faced with still another long-term drought, the city council voted unanimously to reactivate the Charles E. Meyer Desalination Plant. In May 2017, after start-up testing, the City began distributing desalinated water into the City’s water system.
Pass the Water; Skip the Salt
The updated desalination plant supplies a new source of potable water to City residents for household use, plus the preservation of trees and plants, regardless of rainfall or drought, thanks to the availability of the largest reservoir on the planet, the Pacific Ocean, right at our doorstep, containing a third of all the water on Earth.
Drawing a tiny amount of water from the vast Pacific Ocean reservoir makes more ecological sense than building new surface reservoirs inland at an estimated cost of a billion dollars each, and then attaching them to the overloaded State Water System, or spending $22 billion for the governor’s pet Twin Tunnels project.
Neither the City nor the Montecito Water District (MWD) is in a position to discuss the details of negotiations at this time, as they work toward a water purchase agreement. However, many of the details are already public knowledge.
Montecito is seeking the City’s commitment to provide a 50-year supply of 1,250 AFY from the City, with the City retaining the discretion to supply Montecito with State Water, imported water, Cachuma or Gibraltar water, groundwater, and, of course, desal.
The City uses approximately 10,000 AFY of water. Pre-drought usage was approximately 14,000 AFY. The Montecito Water District currently uses approximately 4,000 AFY. Pre-drought usage was approximately 6,500 AFY.
With the election of Floyd Wicksand Tobe Ploughto the Montecito Water Board in November 2016, shared development expense agreements were signed, and good-faith negotiations began between professional engineers on both sides to develop costs and terms for a water agreement with the City.
Under current permits, the City is allowed to nearly triple its desalination plant capacity from 3,125 AFY up to 10,000 AFY. The intake system has already been sized to accommodate the 10,000 AFY; the modular seawater treatment process is expandable, as needed, by adding additional trains; the outflow system to carry the desalinated water from the seaside plant up to the Mission for highline City users, and then on to the Cater Water Treatment Plant for connection to the South Coast Conduit, is in final design.
Desalination Plant Cost
Capital costs to reactivate the desalination plant were $72 million, financed over 20 years at a super-low 1.6% interest rate, which equates to $4.2 million in annual debt service.
A $10 million state grant was awarded to the City in the spring of 2018 by the California Department of Water Resources (DWR) from the $7.5 billion in Prop 1 state funding passed by the voters in November 2014 to improve California’s water reliability.
Annual operating costs are estimated to be about $4.1 million at full production. Ralph Felix, IDE America’s plant manager, noted that the new desal plant is so automated that it only requires a staff of 12 people for 24/7 operation. Amazingly, the plant can be monitored from a home laptop, but at least two operators are present on each shift for contingencies.
Seawater Intake System
Seawater enters the City’s desalination plant from 2,500 feet offshore, passing through wedge wire screens made of a durable copper-nickel alloy that have one-millimeter openings to minimize marine life entrapment and impingement. The one-millimeter openings are the size of a paper clip.
Treatment of Intake Water
A combination of intake screens, static mixers, gravity filters, and RO filters remove suspended solids. The system removes sediment, bacteria, viruses, and minerals (including salt).
The guts of the plant are the salt-removing modular reverse osmosis (RV) membrane trains that process the sea water. High-pressure pumps push the water through semi-permeable membranes at 850 pounds per square inch to remove salt and dissolved minerals and other impurities. Outflows include: 1) desalted water for further treatment and 2) concentrated brine.
The brine leaving the plant is roughly twice as salty as normal seawater, so it is diluted with a small portion of the City’s treated wastewater before being discharged back into the ocean 1½ miles offshore.
Mineralization & Outflow
The desalted water goes through a further disinfection, re-mineralization, and chlorination process. For use in the northern tier of the City, and for possible use in Montecito, the desalinated water can be pumped to the Cater Water Treatment plant, allowing MWD to receive its share of treated Cachuma water, state water, or desal water from the City through the South Coast Conduit.
The City has recently completed a potable reuse feasibility study for expanded use of recycled water. Advanced treatment of recycled water could allow for either indirect potable use through injection into its groundwater basin, or direct potable reuse when that use is permitted by California law.
The reactivated plant uses 40% less energy than the original design, reducing power demand and carbon footprint. Some residents question whether a sub-surface intake system should be required to replace the current open ocean intake system. The City conducted a lengthy study that concluded that sub-surface intakes are not feasible at this time for multiple reasons, among which are negative impacts to sensitive habitats in Mission Lagoon and unproven technology.
MWD believes that a water purchase agreement, with no ownership and no residual value by MWD, creates a major revenue stream for the City, allowing it to reduce both its current plant capital costs and operating cost loads on City ratepayers.
In addition, MWD believes that adding a new train to the desal plant to process an additional 2,500 AFY of desalinated water, at the City’s option, not only drops the unit production cost for both parties, but it blunts City ratepayer criticism that the City is providing its own water to benefit Montecito.
Win-Win negotiations always seem to work best in the rare instances that they can be negotiated and agreed to by rational potential partners.