Desalination - Advantages and Disadvantages

DESALINATION

ADVANTAGES + DISADVANTAGES

BY JACKIE HOGAN BIO 338

INTRODUCTION+BACKGROUND DESALINATION TECHNOLOGY, IN SOME FORM, HAS BEEN USED FOR THOUSANDS OF YEARS. PUT SIMPLY, DESALINATION IS THE CONVERSION OF SALINE WATER, OR SALT WATER, INTO FRESH WATER. IN ORDER TO CREATE THE FRESH WATER, THE DISSOLVED SALTS AND MINERALS FOUND IN SALINE WATER NEED TO BE REMOVED. THIS CAN BE DONE IN A FEW DIFFERENT WAYS. THERMAL ENERGY AND REVERSE OSMOSIS ARE TWO OF THE MOST WIDELY USED METHODS UTILIZED IN DESALINATION. AS THE EFFECTS OF CLIMATE CHANGE BECOME MORE AND MORE PREVALENT, THERE IS A GREATER NEED FOR FINDING WAYS TO MITIGATE THE PROBLEMS CAUSED. LACK OF AVAILABILITY OF FRESH, CLEAN DRINKING WATER IS IMPACTING POPULATIONS ALL OVER THE WORLD AND DESALINATION IS ONE WAY TO COUNTERACT WATER SCARCITY. DESALINATION IS NOT A PERFECT TECHNOLOGY, CRITICS RECOGNIZE THAT IT IS EXPENSIVE, REQUIRES A GREAT DEAL OF ENERGY, AND IMPACTS THE ENVIRONMENT, WHILE PROPONENTS BELIEVE THAT THE BENEFIT OF A RELIABLE SOURCE OF FRESHWATER MAKES IT WORTH IT. DESALINATION PLANTS EXIST AND ARE BEING BUILT ALL OVER THE WORLD. ONE AREA PARTICULARLY CONCENTRATED WITH THESE PLANTS IS THE MIDDLE EAST. A DRY CLIMATE AND AN EXPLODING POPULATION CREATED A WATER CRISIS, LEADING TO ALMOST HALF OF THE TOTAL AMOUNT OF DESALINATION TO OCCUR IN THIS REGION(U.N. 2009). ANOTHER DROUGHTSTRICKEN AREA WITH AN INCREASING POPULATION IS SOUTHERN CALIFORNIA. SAN DIEGO COUNTY “IMPORTS” THE MAJORITY OF THE WATER WE USE, WITH ABOUT SIXTY PERCENT FLOWING IN FROM THE COLORADO RIVER, AND MORE FROM NORTHERN CALIFORNIA. IN 2015, THE BUD LEWIS DESALINATION PLANT OPENED IN CARLSBAD, CALIFORNIA, COSTING $1 BILLION. BEING THE LARGEST DESALINATION PLANT IN THE WESTERN HEMISPHERE, IT HAS THE POTENTIAL TO CREATE ABOUT 50 MILLION GALLONS OF FRESH WATER, DAILY. AT LEAST FIFTEEN MORE DESALINATION PLANTS ARE PLANNED OR BEING BUILT IN CALIFORNIA(FIKES, 2015).

Photo from San Diego County Water Authority

Graph from www.carlsbaddesal.com

ADVANTAGES OF DESALINATION

THERE IS A LARGE POPULATION IN THE WORLD THAT DOES NOT HAVE RELIABLE ACCESS TO CLEAN, FRESH WATER. ESPECIALLY IN COASTAL AREAS, A DESALINATION PLANT COULD BE INVALUABLE IN SOLVING WATER SCARCITY. MOST OF THE WORLD IS COVERED IN SALT WATER MAKING IT AN ABUNDANT RESOURCE THAT CAN BE USED WITHOUT CAUSING A LOT OF HARM. WE DO NOT HAVE TO WORRY ABOUT USING TOO MUCH SEA WATER AS WE DO FROM OUR CURRENT WATER RESERVOIRS. Photo from www.dnaindia.com

ADVANTAGES OF DESALINATION DESALINATION CAN HELP TO ALLEVIATE THE STRAIN ON MANY OF THE FRESHWATER SOURCES WE ARE USING TODAY, LIKE THE COLORADO RIVER. AS DISCUSSED EARLIER, SAN DIEGO GETS MOST OF THE FRESHWATER USED IN THE COUNTY FROM THE COLORADO RIVER, BY WAY OF THE 242-MILE AQUEDUCT THAT SPANS THE STATE. THE COLORADO RIVER SUPPLIES WATER TO SEVEN STATES AND AS IT’S BASIN EXPERIENCES DROUGHT CONDITIONS THE LEVEL OF WATER IN THE RIVER CONTINUES TO DECREASE. THE RIVER IS HEAVILY DAMMED, FURTHER RESTRICTING THE FLOW OF THE RIVER AND CAUSING NUMEROUS ENVIRONMENTAL PROBLEMS. THESE BODIES OF WATER MAY BE ABLE TO START TO GET BACK THEIR NATURAL FLOW AND START RESTORING THE SURROUNDING HABITATS.

Photo from www.telegraph.co.uk

DISADVANTAGES DESALINATION IS A COMPLICATED PROCESS, REGARDLESS OF THE PLANT BEING OPERATED WITH REVERSE OSMOSIS, LIKE THE ONE IN CARLSBAD, OR THERMAL ENERGY. IT ALSO REQUIRES A GREAT DEAL OF ENERGY AND FUEL TO END UP WITH DRINKABLE WATER. IN FACT, MOST OF THE EXPENSE OF DESALINATION GOES TOWARD ENERGY COSTS TO MAINTAIN PRODUCTION AT THE PLANT. AS CLIMATE CHANGE WORSENS AND THE SALINITY OF THE OCEAN INCREASES, MORE AND MORE ENERGY WILL BE NEEDED TO COMPLETE THE DESALINATION PROCESS. THIS EXPENSE IS PASSED ON TO THE CONSUMER. EVERY THOUSAND GALLONS OF FRESH WATER OBTAINED FROM CURRENT SOURCES COSTS ABOUT $2, BUT EVERY THOUSAND GALLONS OF FRESHWATER CREATED THROUGH DESALINATION CAN COST UP TO $5(BIENKOWSKI, 2015). SOME FAMILIES MAY BE ABLE TO AFFORD THAT COST CHANGE, BUT WITH THE POSSIBILITY OF WATER BILLS BEING DOUBLED, MANY COMMUNITIES MAY STRUGGLE. CALIFORNIA'S ECONOMY IS ALSO HEAVILY BASED IN THE AGRICULTURE INDUSTRY, WHICH ACCOUNTS FOR ABOUT ONETHIRD OF THE FRESH WATER USED IN THE STATE.

As farms are using much more water than a regular household, the cost of their water may become too much to bear. The building of desalination plants is also incredibly expensive. The Carlsbad desalination plant was also more expensive than similar plants built in other countries because, in the U.S. and specifically California, the had to take the public's concern into account. Litigation, mitigation, environmental impact assessments and permitting delayed the construction almost ten years(Siegel, 2017).

DIAGRAM FROM EFDCORP.COM ONE ENVIRONMENTAL CONCERN IN THE PROCESS OF DESALINATION IS THE CREATION OF BRINE AND IT'S DISPOSAL. BRINE IS A BYPRODUCT OF DESALINATION. IT IS WATER HEAVILY CONCENTRATED WITH SALT, MUCH SALTIER THAN REGULAR SEA WATER. BESIDES SALT, THERE MAY ALSO BE CHEMICALS, LIKE CHLORINE, USED TO TREAT THE SALT WATER LEFTOVER IN THE BRINE. PRESENTLY, THE MOST COMMON WAY TO DISPOSE OF BRINE CREATED IN THE DESALINATION PROCESS IS TO SIMPLY RELEASE IT INTO A NEARBY WATER SYSTEM, WHETHER IT BE A RIVER, STREAM, ESTUARY OR OCEAN. LOCALLY AT THE DESALINATION PLANT IN CARLSBAD, THE SAN DIEGO UNION TRIBUNE ESTIMATES THAT FOR EACH GALLON OF FRESH WATER THAT IS CREATED, TWO GALLONS OF SALINE CONCENTRATED BRINE ARE PRODUCED(CARTAMIL, 2015). THE DISCHARGE WILL AFFECT THE CHEMICAL COMPOSITION OF THE WATER POSSIBLY DISTURBING THE ECOSYSTEMS. THE BRINE IS PARTICULARLY DANGEROUS TO MARINE ORGANISMS OCCUPYING MORE STAGNANT WATER SYSTEMS WHERE THE WATER DOES NOT HAVE ENOUGH MOVEMENT TO DISPERSE THE BRINE. THERE ARE OTHER OPTIONS FOR THE DISPOSAL OF THE BRINE, THAT ARE NOT AS HAZARDOUS TO ECOSYSTEMS SURROUNDING THE PLANT. THE BRINE CAN BE USED IN IRRIGATION OF PLANTS THAT CAN TOLERATE THE HIGHER SALINITY. THERE IS ALSO A TECHNOLOGY CALLED ZERO LIQUID DISCHARGE OR ZLD. WHEN ZLD IS UTILIZED THE BRINE IS CONVERTED FROM A SOLID TO A LIQUID. THE PROCESS OF THIS KIND OF DISCHARGE IS EXPENSIVE AND IS ENERGY INTENSIVE AS WELL. THE SOLID WASTE ALSO NEEDS TO BE DISPOSED OF AND WOULD USUALLY GO TO A LANDFILL INSTEAD OF THE OCEAN. FINALLY, THE BRINE CAN BE RELEASED INTO AN EVAPORATION POND WHICH, OVER TIME ALLOWS THE WATER TO EVAPORATE LEAVING BEHIND THE SALT SOLIDS THAT NEED TO BE DISPOSED OF. ON TOP OF THE POLLUTION CAUSED BY THE DISPOSAL OF THE BRINE CONCENTRATE, THE INTAKE OF OCEAN WATER CAN LEAD TO SOME PROBLEMS THAT IMPACT MARINE ECOSYSTEMS. SMALL FISH AND INVERTEBRATES CAN BE KILLED AS BY-CATCH WHEN THEY ARE IN THE SALT WATER THAT IS TAKEN IN AT DESALINATION PLANTS. SOME OF THIS CAN BE AVOIDED BY PUTTING SAFEGUARDS IN PLACE BUT, CURRENTLY, THERE IS NO PERFECT WAY FOR THE INTAKE OF SALT WATER THAT CAN ELIMINATE ALL HARM TO MARINE SPECIES.

CONCLUSION + OPINION WHILE THERE ARE ADVANTAGES AND DISADVANTAGES TO DESALINATION I BELIEVE IT MAY BE NECESSARY DUE TO A GROWING POPULATION IN CALIFORNIA AND CONTINUED DROUGHT CONDITIONS. I THINK IF DESALINATION PLANTS CONTINUE TO BE BUILT AND INCREASE PRODUCTION IT IS IMPORTANT TO MONITOR THEM TO MAKE SURE THEY ARE DOING EVERYTHING POSSIBLE TO NOT DISTURB SEA LIFE. THIS INCLUDES FINDING A SUITABLE WAY TO DISPOSE OF BRINE CONCENTRATE AND TRYING TO MINIMIZE HARM TO MARINE SPECIES AT THE INTAKE OF SALTWATER. ALSO LOOKING FOR FUTURE INNOVATIONS TO DECREASE THE AMOUNT OF ENERGY USED IN DESALINATION, THUS DECREASING ITS COST, IS VITAL IF DESALINATION IS TO HELP TO FIX WATER SCARCITY ISSUES. I THINK THE BEST COURSE OF ACTION IS TO ENCOURAGE PEOPLE TO CONTINUE TO CONSERVE WATER AND LOOK FOR INNOVATIONS THAT CAN SAVE WATER IN HOMES AND BUSINESSES. IN THE MEANTIME, DESALINATION CAN BE USED AS A VALUABLE RESOURCE TO MAKE SURE EVERYONE IS GETTING ENOUGH WATER.

REFERENCES • BELESSIOTIS, VL, AND E. DELYANNIS. "THE HISTORY OF RENEWABLE ENERGIES FOR WATER DESALINATION." DESALINATION 128.2 (2000): 147-159.

• BREMERE, INGRIDA, ET AL. "HOW WATER SCARCITY WILL EFFECT THE GROWTH IN THE DESALINATION MARKET IN THE COMING 25 YEARS." DESALINATION 138.1-3 (2001): 7-15.

• CARTAMIL, DANIEL. MARINE ENVIRONMENTAL DAMAGE WILL BE A MINIMAL TRADEOFF. SAN DIEGO UNION TRIBUNE , 28 NOV. 2015, WWW.SANDIEGOUNIONTRIBUNE.COM/OPINION/COMMENTARY/ •

SDUT-DESALINATION-CARLSBAD-MARINE-LIFE-CARTAMIL-2015NOV28HTMLSTORY.HTML.

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ELIMELECH, MENACHEM, AND WILLIAM A. PHILLIP. "THE FUTURE OF SEAWATER DESALINATION: ENERGY, TECHNOLOGY, AND THE ENVIRONMENT." SCIENCE 333.6043 (2011): 712-717.

• FIKES, BRADLEY J. STATE'S BIGGEST DESAL PLANT TO OPEN: WHAT IT MEANS. SAN DIEGO UNION TRIBUNE 13 DEC. 2015, WWW.SANDIEGOUNIONTRIBUNE.COM/NEWS/ENVIRONMENT/SDUT-POSEIDONWATER- DESALINATION-CARLSBAD-OPENING-2015DEC13-HTMLSTORY.HTML. • LATTEMANN, SABINE, AND THOMAS HÖPNER. "ENVIRONMENTAL IMPACT AND IMPACT ASSESSMENT OF SEAWATER DESALINATION." DESALINATION 220.1-3 (2008): 1-15.

• ROGERS, PAUL. "NATION’S LARGEST OCEAN DESALINATION PLANT GOES UP NEAR SAN DIEGO; FUTURE OF THE CALIFORNIA COAST." SAN JOSE MERCURY NEWS 29 (2014).

• U.N. PUBLICATION. ROLE OF DESALINATION IN ADDRESSING WATER SCARCITY. E/ESCWA/SDPD/2009/4, NOVEMBER 2009.