California Desalination Report With More Than A Grain Of Subjectivity Part 3

By Author: Nikolay Voutchkov
Total Articles: 76
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How unique is the impact of desalination operations on the environment?
The PI report points out two key areas of desalination project impact on the environment: the effect of their high-salinity discharge on aquatic life and the potential impingement and entrainment of plant intake facilities. Although the report claims that safe disposal of plant concentrate is a challenge, it fails to mention that there are over two decades of experience of safe concentrate disposal from both seawater and brackish water
desalination plants in the US and worldwide. It also ignores that there are no known cases where desalination discharges have actually caused significant environmental alterations of the ambient aquatic environment. In recognition that desalination plant concentrate can be managed without any measurable challenges, after rigorous technical and scientific review and analysis, in the summer of 2006, the San Diego and Santa
Ana Regional Water Quality Control Boards granted waste discharge permits to the 50 mgd Carlsbad and Huntington Beach desalination plants. These permits encompass desalination plant concentrate ...
... and the other side-streams (membrane cleaning solutions and pretreatment filter backwash) generated at the desalination plants.

The PI report claims that impingement and entrainment of marine organisms are among the most significant environmental threats associated with seawater desalination. This claim, however, is not supported by any data nor by any full-scale studies of existing seawater desalination intakes; neither is it substantiated by the observations and/ or monitoring of aquatic life in the vicinity of plants operating along coastal Spain, Israel or Australia—countries which have stringent regulations and elaborate legal and monitoring frameworks for protecting marine environments, comparable to that of California. The report also remains silent on the fact that existing state water project's open intakes along the Sacramento Bay-San Joaquin Delta collect source water from aquatic environments that are much richer in life and more fragile in ecological
balance than the bare ocean bottom areas in the vicinity of most of the proposed open-intake seawater desalination intakes and the fact that these fresh water intakes collect an order-of-magnitude larger volume of water than the proposed desalination projects. This subjective review
of environmental impacts of the desalination plants underrates the authors' ‘genuine' concerns regarding the impact of various water supply practices on California's environment and the fair comparison of this impact.

How does desalinated water quality fare against other alternatives?

The PI report states that use of desalinated water can be acause of health concerns and may result in water distribution system corrosion. Using outdated information regarding boron rejection of seawater membranes, the report claims that desalinated seawater can contain boron at levels exceeding the applicable safe drinking water requirements. The report states that RO membranes can remove only between 50 and 70 percent
(of the 4.5 mg/L of boron contained in the ocean water) and therefore may exceed the California Department of Health Services Action Level for boron of one mg/L.

Practitioners of seawater desalination know well that the quoted boron removal levels refer to membranes that are two generations old. Currently available seawater desalination membranes can reject over 90 percent of the boron contained in the seawater and according to
the September/October 2006 issue of the International Desalination Association's Water News, research is underway to achieve 93 to 95 percent boron removal.

Similarly, using outdated information or misinterpreting existing studies or data, the report raises unfounded concerns regarding other water quality parameters such as disinfection byproducts (DPBs), algal toxins and mineral content of the desalinated water. The report fails
to acknowledge that over two dozen large, existing brackish water desalination plants in Florida have been successfully supplying drinking water (of quality and corrosion potential similar to that of the proposed California desalination plants) for over 15 years without health or distribution system related problems. Similarly, the hundreds of seawater desalination plants worldwide have been providing safe potable water of reliable and consistent quality for over two decades without causing problems such as the 1993 Cryptosporidium outbreak in Milwaukee, Wis. or the recent corrosion-related lead water quality challenges in Washington, D.C.

Although desalinated water from the numerous existing brackish water desalination plants in California have been distributed to the public water supply for decades, the report makes the erroneous statement that the, overall effects of desalinated water on California water distribution systems are not yet known. Obviously, they are—but apparently not to the writers of the PI report.

Summary and conclusions

The recently published Pacific Institute report offers a subjective opinion of the viability of desalination in California that self-servingly renders most of the ongoing desalination initiatives immature. What is immature, however, is the knowledge and understanding of the report's authors of the current status of desalination technology and their understanding of the critical importance of the development of a diversified water portfolio
that includes a well balanced mix of conventional water supply sources, water reclamation, conservation and desalination for the long-term sustainability of the California water supply and socioeconomic development of the state.

PI report's opinion is not shared by the people of California, who in 2002 voted in support of Proposition 50, opening the opportunity for exploring brackish and seawater desalination as a new and reliable source of water supply for the state. Nor it is endorsed by the California
Department of Water Resources, which incorporated the development of 450 to 500 mgd of new desalination projects into their 2005 California Water Plan.

The key fatal flaw of the report is that it fails to recognize the wealth of international and domestic desalination experience and to understand the applicability of this experience to the site-specific conditions of California. Rather than pointing to proven solutions and state-of-the art knowledge associated with the use of desalination technology, the report tries to paint a picture of a water supply technology
of enigmatic problems and effects unknowable and not yet seen in California. Proving the century-old Will Rogers line that common sense is not that common, the Pacific Institute desalination report contributes little practical value or constructive input toward solving California water challenges and provides no useful, up-to-date information for readers interested in gaining an accurate and objective understanding of
the challenges and solutions associated with the use of desalination today.

Recognizing the value and importance of desalination for the state over the next five to 10 years, many California communities plan to make desalination a permanent part of their water portfolio. Approximately 20 medium and large desalination plants supplying up to 5.7 percent of California's total urban water demand are projected to be built by the year 2015. Although existing fresh water sources, conservation and reuse will continue to play a central role in the state's long-term water supply strategy, seawater desalination has unique appeal to many coastal communities because it allows access to a reliable and droughtproof source of drinking water that can be developed and controlled locally at
costs competitive to incremental expenses associated with the development of other water supply alternatives.