Desalination A National Perspective (2008) / Chapter Skim
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7 Implementation Issues
7 Implementation Issues
Pages 182-211
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From page 182... ...
This chapter provides a summary of implementation issues, including institutional matters, that need to be addressed by water providers when developing desalination projects. The issues covered in this chapter include environmental regulatory requirements, capital and operating costs, public perception, siting considerations, planning and design issues that consider the uncertainty of new technology, product water quality changes within conveyance systems, alternative project delivery and procurement methods, and project financing.
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From page 183... ...
Most of the permits provide for extensive review and comment from resource agencies and the public. Source Water Permits Source water permit requirements depend on the location of the desalination facility.
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From page 184... ...
Potable Water Permit The potable water permit, as required by the Safe Drinking Water Act, is typical of permits required for any drinking water treatment plant. This permit is not required if the desalted water is used for nonpotable (e.g., irrigation)
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From page 185... ...
. Nationally, separate classification of drinking water treatment plant by-products would require an amendment of the Clean Water Act.
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From page 186... ...
PUBLIC PERCEPTION Successful implementation of a desalination plant requires more than a successful resolution of technical issues. Affected persons in the area are often able to slow or block implementation if public perception is negative, whether or not a concern is justified in the particular project.
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From page 187... ...
, the public may perceive water produced by membrane-based desalination as not sufficiently protective of public health. Water providers can address this concern by educating the public on the technical advances of water treatment processes and the effective constituent removal efficiencies of these processes.
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From page 188... ...
Nevertheless, the public may be more comfortable with the reliability of familiar treatment processes using traditional sources. Water providers can address this concern by educating the public on the number of successful international seawater desalination projects and U.S.
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From page 189... ...
Water providers can address this concern by educating the public on the incremental cost of desalination as compared to other water supply alternatives. The public can also be informed that total project cost (including operating cost)
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From page 190... ...
Co-location with a power station was used for the Tampa Bay Seawater Desalination Plant and has been considered for numerous plants in the United States and worldwide, such as the proposed seawater desalination plant in Carlsbad, California. At the Tampa Bay Seawater Desalination Plant, the intake and discharge are connected directly to the cooling water discharge outfalls of the Tampa Electric Big Bend Power Station (Figure 7-1)
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From page 191... ...
The source water for a desalination plant co-located with a power plant is the cooling water discharge, which has already passed through screens similar to those used on surface water intakes for desalination plants. Therefore, a co-located desalination plant generally does not require the construction of a separate intake structure, intake pipeline, or screening facilities (i.e., bar-racks and coarse screens)
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From page 192... ...
In the absence of co-location with power plants using oncethrough cooling, seawater desalination facilities will have to develop other approaches to concentrate discharge, such as implementation of offshore diffuser technology. Should the power plant discontinue operating on an interim or permanent basis, water withdrawals would have to continue to provide source water and, in some cases, dilution of the concentrate.
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From page 193... ...
Coastal water providers can, however, take advantage of the opportunities to learn from successful large-scale seawater desalination projects that have been developed outside of the United States. Projectspecific variations (e.g., salinity, temperature, scope of work, local regulations and business practices)
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From page 194... ...
. In typical pilot studies, small-scale pilot plants use the same feedwater being considered for the desalination plant; and to ensure that the proposed design will operate properly under seasonal variations in source water quality, it is also important that pilot testing be performed for an entire year.
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From page 195... ...
. Of the 48 projects awarded through 2006, 15 are pilot and demonstration projects, representing nearly $17 million of the $46 million that has been allocated.1 FINISHED WATER QUALITY CHANGES AND EFFECTS OF EXISTING INFRASTRUCTURE Significant changes in water quality, such as that experienced when a utility brings a desalination plant or any new water supply source online, can affect the water and wastewater infrastructure and, without proper mitigation steps, can impact the quality of the water delivered to consumers.
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From page 196... ...
The seawater desalination plant at Ashkelon, Israel, serves as an example of the need for attention to the effects of water quality changes on downstream wastewater systems. At the Ashkelon plant, low alkalinity in the desalinated product water created problems in the wastewater treatment plant.
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From page 197... ...
applied to the source water or the pipe material in the distribution system. Therefore, selection of seawater desalination as a component of a utility's water portfolio should not result in adverse water quality conditions as long as proper post-treatment measures are taken (Taylor et al., 2005)
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From page 198... ...
. PROJECT DELIVERY METHODS The process of planning, designing, financing, constructing, and operating a desalination facility can be accomplished through a number of different approaches involving the water supplier (typically a public water provider)
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From page 199... ...
. Alternative Project Delivery Methods Alternative project delivery methods offer several advantages over the traditional model, because the designer, construction contractor, and operator (if included)
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From page 200... ...
This can enable site work, such as clearing and grubbing, and some structural foundation work to commence earlier than a DBB process may allow. Three of the most common alternative project delivery methods -- design-build (DB)
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From page 201... ...
DBO approaches are often used where project performance and the value of the service to TABLE 7-1a. Summary of Common Project Delivery Methods.
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From page 202... ...
• Potential for high and reduces collaboration derstood by owner degree of control and • Linear process increases • Project requires a involvement by owner schedule duration high degree of public • Independent • Prone to disputes and oversight oversight of construction creates opportunities for risk • Owner wants to be contractor avoidance by the designer extensively involved in and construction contractor the design • Low-bid contactor • Schedule is not a selection reduces creativity priority and increases risks of per formance problems • Risks are mostly borne by the owner • May not allow for economies of scale in opera tions • For new technologies, operability may not be the primary design concern Design- • Collaboration be- • Owner may not be as • Time is critical BUT Build (DB) tween designer and familiar with DB process or existing conditions and contractor contract terms desired outcomes are • Parallel processes • Reduces owner control well defined reduce duration and oversight.
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From page 203... ...
. The public water provider commits to purchase some quantity of water from the desalination facility at an agreed-upon price over some period of time.
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From page 204... ...
In November 2004, Tampa Bay Water retained a new construction completion and operations and maintenance contractor (American Water -- Pridesa) using the DBO project delivery method to complete $30 million of repairs and modifications to the facility that would ultimately deliver a reliable desalination water source for the region.
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From page 205... ...
The Tampa Bay Seawater Desalination Project is an example of a public water provider using alternative delivery methods to implement a desalination project. This project delivery started as a DBOOT and is now being implemented through a DBO arrangement.
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From page 206... ...
Following is a discussion of the public and private ownership financing considerations for desalination projects. Public and Municipal Financing The ability for public water providers to obtain financing through bond issues is largely controlled by credit ratings established by three major Wall Street rating agencies (Fitch Ratings, Moody's Investors Service, and Standard & Poor's)
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From page 207... ...
In summary, financing desalination projects should not present a significant implementation challenge for large public water providers. Small public water providers, however, may find it more difficult to finance desalination projects given the limited financial resources in rural areas, the limited access to capital markets, the limited managerial re
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From page 208... ...
Desalination plants are eligible for funding through the state revolving funds. Allotments to states for 2006 through 2009 are based on a 2003 needs survey.
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From page 209... ...
. Private Financing Desalination projects may utilize traditional equipment financing schemes with 5- to 7-year repayment and prevailing load interest rates, with loan guarantees provided by the project developer.
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From page 210... ...
Key resources include capital funds and financing capability, funds for electricity or the availability of other sources of energy, access to acceptable source waters, and cost-effective and environmentally sustainable concentrate management options. The implementation process includes the following main components: public involvement programs, regulatory requirements, procurement and project delivery establishment, financing, technology selection, and finished water quality management.
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From page 211... ...
Water providers should consider all project delivery models available and select the most appropriate model. The project delivery method selected can affect the amount of risk carried by the water provider, the access to innovative technology, and the time to project completion.
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