West Basin Municipal Water District’s proposal to build a desalination plant in the South Bay has been met with backlash from environmentalists in the community.
The local water supplier is working on a draft environmental impact report (EIR) to evaluate two potential sites for a desalination plant: the NRG power plant site in El Segundo next to Manhattan Beach and the AES power plant site in Redondo Beach. A desalination site would produce 20 to 60 million gallons of potable drinking water per day.
West Basin’s general manager, Richard Nagel, emphasized the EIR is simply being prepared to examine options and no definite decision has been made to build a desalination plant.
“The board has not made a decision at all. This is just doing due diligence, a normal natural step to evaluate the prospect of potentially building an ocean desalination facility in the future,” said Nagel.
The EIR’s release, which was slated to be last June, has been delayed to December 2016. That didn't stop a planned special townhall meeting to inform the public about alternative options to desalination last week.
Desalination and water recycling
Some attendees, like Craig Cadwallader with the South Bay chapter of the Surfrider Foundation, argued that desalination is far from efficient when compared to other alternatives, like water recycling.
“The efficiency of desalinated ocean water is about 50 percent. So for West Basin to get 20 million gallons a day of potable drinking water, they would need to suck in 40 million gallons a day,” Cadwallader explained. “If they recycle water it’s 85 percent efficient. You’d only need to take in 24 million.”
To answer detractors, Nagel said in a separate interview that West Basin is exploring desalination as an additional source of water and it still intends to expand its water recycling program.
However, a water think tank expert, Heather Cooley with the Pacific Institute, said doing both desalination, a process through which salt is removed from salt water in order to make water suitable for drinking and other uses, and water recycling can potentially result in an excess of water.
In a phone interview, Cooley said often times desalination plants are built under the assumption that the demand for water will continue to grow.
“What the data shows is that we’re using less water today than we were in the 1980s despite population growth because of efficiency improvements,” Cooley said. “And those efficiency improvements are going to continue.”
Nonetheless, West Basin's Nagel stressed that the major source of water for the South Bay is imported and dependent on rainfall hundreds of miles away, as well as snow pact that is unpredictable. Nagel urged that this water would become even more difficult to predict in the future because of climate change.
“The thing that ocean desalination and water reuse do is both create drought-proof dependable supplies of water, meaning that they’re independent of hydrology conditions anywhere,” Nagel said.
Problems with desalination
During last week's meeting, opponents of the desalination plant, like Los Angeles Waterkeeper, Surfrider Foundation and Heal the Bay, extolled problems that could arise from a desalination plant. Many of these are the same issues Cooley sees with desalination plants.
Cooley said in a phone interview desalination plants have three problems: the cost, large energy use and impact on marine life.
Of all the ways to supply water, desalination is one of the most expensive Cooley said.
“As a result, when a facility is built, the water costs will go up in response,” Cooley said. “So that can be especially problematic for low income residents who may already struggling to make ends meet.”
The second problem with desalination, according to Cooley, is that it is among the most energy intensive ways to supply water.
“As we look to the future of climate change and in the interest of reducing greenhouse gas emissions, building an energy intensive supply is at odds with that sort of longer term stretch,” Cooley explained. “There can be ways to help mitigate those additional greenhouse gas emissions associated with the energy intensive water source but those too can raise the costs.”
Impact on marine life is the third issue that arises from building a desalination plant, Cooley said.
Nagel said in a phone interview that their desalination plant would be built such that marine life would be minimally impacted. He said West Basin would use “wedge wire screens” with one millimeter slot openings. The screens are “100 percent protective of all juvenile and adult marine life.”
However, Cooley said that this does not account for eggs and larvae that are smaller than one millimeter that could potentially be pulled in and killed during the desalination process.
Cooley said the discharge of brine, or extra salty water (a byproduct of desalination) can hurt marine life. Brine is twice the salinity of ocean water. As a result, when it’s discharged back into the ocean, it will sink to the bottom of the ocean because of its density. This accumulation of brine can be problematic for organisms that live at the ocean's bottom.
West Basin's Nagel said diffusers would be used to help mitigate the discharge of brine.
“For diffusers I use the metaphor of if you put a hose back out in the ocean and then strain it off,” Nagel said. “You can mechanically engineer these to emit this saltier water or discharge it back out in the ocean, and it’s safe to have it blend in with the current ocean water.”
Cooley said diffusers don’t wholly solve brine problems.
“The diffuser promotes mixing and so it reduces the sort of area at which you would have an elevated salinity,” Cooley said. “It’s sort of the best available technology but that doesn’t mean it completely eliminates the impact. It just reduces it to the best we are able to given current technology.”
After last week's meeting, West Basin issued a statement reiterating that West Basin has not decided to build a desalination facility in the South Bay.
Instead, it is “exploring ocean water desalination through scientific research, educating our communities about the program, and conducting an Environmental Impact Report (EIR) to help us understand and examine any potential project impacts.”
The statement goes on to urge the public to continue to provide input and to attend an ocean desalination briefing and tour on August 13 at the Edward C. Little Water Recycling Facility in El Segundo at 9 a.m.