A-Salt with Intense

 

A-Salt with Intense

Desalination – Can we afford it… or can we afford not to afford it?

Some call it “desal” these days, but simply, it is the removal of salt from seawater or highly mineralized groundwater to make it potable and/or useable for irrigation. Nature has its own desal process: evaporation of salty water, which returns freshwater back to earth in the form of rain. Technology to implement a human-controlled desal effort on a meaningful scale is exceptionally expensive, heavily energy inefficient. Distilling is easy, but it is often based on burning fossil fuel (or very slow solar exposure) to generate the evaporation to separate water (steam which condenses) from salt. Electrolysis was the most common man-utlized process until osmosis (forcing saltwater through a membrane that is impermeable to salt) became the more efficient method. Other systems, such as forcing saltwater through nanotubes, is a similar, but today osmosis is the most common commercial application.

Absent a massive storehouse of mineral-laden groundwater, fairly rare, desal generally takes place seaside and only in regions where accessing useable freshwater faces dwindling alterntaive opportunities. Read: desperation. The processing plants are exceptionally expensive to build, maintain and operate… and energy consumption is generally their achilles heel. But as “drought” morphs into “aridification” (aka “desertification”), as food producing regions run dry and cities run out of drinking water, desal is a real solutiuon… with problems that exceed mere cost and the use of fossil fuel to generate the needed power. As alternative energy becomes more widely available, while the high cost remains, at least the greenhouse risks are mitigated. But then, there are other pipers to pay.

The November 7th Los Angeles Times addresses some of these nasty side effects, in an examination of the resurrection of a desale future for California: “Indeed, desalination is not without downsides. In addition to high energy costs, the process can harm marine life, which can get trapped in pump systems that draw ocean water.

“And then there is the brine — the salty, sludgy byproduct of desalination that typically gets released back into the ocean at the end of the process. A global survey of desalination in 2019 found that plants produce about 5 billion cubic feet of salty brine every day — 50% more than previous estimates… High concentrations of brine can reduce oxygen and increase toxicity in marine environments. That’s caused some to worry about what decades — or even centuries — of desalination could do to the ocean.” Dead zones can develop if heavy concentrations of salt are simply dumped in the ocean, separated from the water that once diluted their toxicity.

So, if you don’t really need that potable water desperately, desal is probably not the answer. But for those regions where lack of useable water is a life-or-death challenge, desal is on the table. Assuming high construction costs are an acceptable expense, sufficient electrical power can be generated by green power generation, the question comes back to all that toxic salt. Some deploy a primitive system roll out a very, very long French drain that returns salt to the ocean gradually over the length of that pipe. Australia was desperate, so a decade ago, they allocated about $14 billion to build desal plants around their massive coastline. They faced all the above issues, failing at some, succeeding at others. But they got water… and yes, consumer water rates did rise significantly.

Today, California is becoming equally desperate. And it does face those same horrific desal-related issues, but it is finally willing to resume that effort in a big way. “Although desalination requires significant energy, California’s current extended drought has revived interest in the technology. Experts are already experimenting with new concepts such as mobile desalination units and floating buoys, and at least four major plants will soon be operational along the state’s coastline…

“Experts are working to solve many of desalination’s challenges, however. The Doheny plant [slated for eco-sensitive Dana Point] for example, will draw seawater through slanted intake wells that run beneath the sea floor. Since they avoid contact with open water, officials say the wells will nearly eliminate the chances of marine life being sucked into intake pipes.

“The facility also plans [see above picture] to ‘commingle’ its brine with South Coast Water District wastewater pipes, diluting it before expelling about two miles out to sea. Though the harm from brine is not completely eliminated, the Coastal Commission said the method was environmentally preferred, and officials say it might serve as a model for future operations.” LA Times. In the end, necessity will push desal solutions to the fore. Already, massive desal facilities are operating in exceptionally arid regions, like Saudi Arabia. As climate change continues to confiscate once arable land, we can expect to see desal as a massive and pervasive technology in our existential struggle against generations of our own self-inflicted pain.

I’m Peter Dekom, and while it may seem unfair that current generations are paying for the environmental folly and excess of past generations, life is not fair!!!!