February 27, 2012
The Externalities of Desalination
A few centuries ago, water use was not a problem because it was seen as a renewable resource that can never be overexploited. However, as population growth increases exponentially, water use likewise increases, depleting water resources at an unsustainable rate. As we use groundwater and surface water at a rate faster than their replenishment rate, we must look towards other sources to obtain water. One proposed solution is desalination, a process that removes salt from saline water. There are three techniques associated with desalination: electrodialysis, freezing, and reverse osmosis. Electrodialysis uses porous members to remove positively and negatively charged salt ions; freezing, by default, removes salt from ice; and reverse osmosis is a process that pressurizes salt water so that water flows through a membrane while the remaining salt are retained (Desalination Process).
Desalinization, while is considered an alternative water supply, has its fair share of negative environmental impacts that could potentially harm large communities of marine organisms. First, the discharge from the desalination facilities carries saline water back into the ocean, which affects benthic organisms that are not accustomed to water with such high salinity. Similarly, discharged water can contain chloride, heavy metals, and cleaning chemicals that would foul ocean water and poison marine animals.
Furthermore, the power consumption required for the process of desalination consumes fossil fuels, which leads to carbon dioxide emissions. As known, carbon dioxide has detrimental effects on the environment, including warming of the earth and human health risks.
Desalination also requires an extensive amount of energy to work. If desalination were to produce half of America’s water, the United States would need to construct 100 more electric power plants (Why Desalination Doesn’t Work). And the energy cost of consuming the necessary amount of energy to produce usable water would exceed the cost to pump water from aquifers or to import the water. Therefore, desalination is not a very cost-effective method and should be used with caution.
In one example, Huntington Beach has proposed desalination in order to provide water to their community. This desalination facility, if successful, would provide 50 million gallons of drinking water per day (Proposed Desalination Plant Wins Permit). However, opponents criticize desalination as energy-intensive and expensive. Furthermore, the construction of the facility near a popular beach would inevitably harm aquatic organisms, which could reduce tourism and recreation.
While it’s necessary to address the current water crisis and some may claim that the damage to marine organisms is insignificant in comparison to the benefits to society, desalination conflicts with the energy-crisis, which would mean that through desalination, we are essentially trading one problem in for another. Especially since most desalination plants require the use of fossil fuels, desalination would exacerbate the energy-crisis, depleting energy resources from other uses.
Despite their criticism, opponents do acknowledge the current water problem, so they propose alternative solutions, including improving irrigation systems and requiring new homes to be water-efficient. These solutions are more focused on conservation of water, which can help communities be more conscientious of their water usage and supply more water to each individual.
http://www.paua.de/Impacts.htm
http://blogs.ua.es/montano/2008/10/28/harmful-effects-of-desalination-on-the-environment/
http://www.livescience.com/4510-desalination-work.html
http://www.arvanitakis.com/en/sw/desalination_process.htm
http://latimesblogs.latimes.com/lanow/2012/02/huntington-beach-desalination-plant-clears-environmental-hurdle.html
Kaylee Yang and Marc Chua are undergraduates in the USC Dornsife College of Letters, Arts and Sciences.
Whenever we consider water options such as desalination, building reservoirs, or pumping water to an area over long distances, it seems that one of the recurring conclusions is that no matter the source of the water on which we depend, we must first and foremost decrease the amount the of water we use. Even if desalinated water is slightly more expensive per gallon than water pumped from the ground, we are still not paying the true price per gallon of drinking water–understandable when considering that water is one of our most basic needs, but not so much when we look at the severe environmental impacts our thirst has caused, especially in California.
One additional problem with desalination is that besides the energy required to actually desalinate the water, the resulting freshwater will have to be transported away from oceans, and potentially over mountains, to reach the main consumers of water in California: agriculture. However, it is undeniable that other sources of water will need to be explored, and hopefully new, more efficient methods of desalination will pose a viable option for freshwater in the not too distant future.
Your critique on desalinization brings up very strong points against it – the discharge, fossil fuel usage, energy, harm to individual organisms, and the high expense. Despite these downfalls, we may have a chance to improve the technology and make it more efficient if we continue research on desalinization. However, developing alternative technologies is always expensive, and the question is how much we are willing to invest in developing alternative methods. An example of this balancing act is reflected in the energy crisis, through the bankruptcy of the solar panel company, Solyndra. The company received over $535 million in federal loans after Obama decided to invest in alternative energy technologies. However, due to high manufacturing costs and competition, the company was not able to survive, resulting in a “failed” investment on behalf of the government. This one case has caused people to question alternative energy and created controversy on whether or not the government should invest in it. As one business reporter put it, “[Solyndra] was never…going to make money, at least in the near future.” This is similar to many other environmental technologies, including desalinization, which is initially very expensive to develop and may not be very cost-beneficial in the beginning. This brings up the big question of whether or not we are willing to balance the short-term disadvantages with potentially positive long-term results. Although Solyndra paints a negative image of developing environmental technologies, we should not let this example deter us from further breakthroughs. It is simply an example that the early stages of any technology are going to be rough, but in terms of the environment we should be concerned with the long-term effects. In the long run, desalinization may not be simply an option, but a necessity, as climate change intensifies water shortages in regions that are more arid. If we do not have freshwater to begin with, conservation methods will not be enough. Although we could proceed with caution, the more we invest in these technologies, the more efficient and beneficial they will be in the future.
http://www.npr.org/2011/09/01/140124818/solar-panel-company-declares-bankruptcy