What is seawater desalination?
Which local governments are investigating seawater desalination as a possible drinking water source?
Why is desalination needed?
Instead of pursuing desalination, can’t we just conserve more water?
What is involved in the Coquina Coast Project?
When is desalination needed?
What is the project’s schedule?
Is the project dead?
How much water will the facility produce?
Who will receive the desalinated water?
Are there economies of scale in building and operating a desalination plant?
Is seawater a safe source of drinking water?
What process will be used to desalt the seawater?
How much seawater does it take to make 10 to 15 million gallons of drinking water?
Is the Intracoastal Waterway being considered as a source for the plant?
What are beach wells and why are they being considered as a source for the plant?
What were the initial beach well investigations?
Are beach wells installed directly on the beach? What size are the wells and what would they look like?
How does the aquifer from which the beach wells would take water differ from the freshwater aquifer?
What chemicals will be used to treat the water and how safely will they be stored?
How do you dispose of the leftover concentrated seawater?
Is seawater desalination safe for the environment?
Could the salt concentration be available for commercial processing to produce a dried salt product?
Will a desalination facility affect fishing or shrimping in the area?
Will pipelines on the ocean floor prohibit the use of fishing nets?
Will a desalination plant affect the Northern Right Whale habitat?
Will red tide affect a desalination plant?
Would an oil spill like the one that occurred in Gulf of Mexico affect the desalination plant?
Will there be marine impacts in the vicinity of the concentrate discharge?
How much energy will the plant use and does FPL have surplus energy available?
What will be done to minimize the carbon footprint or to utilize alternative energy sources for this facility?
How large will the plant be? How much land do you need?
Where are you planning to build the desalination plant?
Will the plant blend with the surrounding community?
Will the plant be noisy?
Will the plant have an odor?
How much will the desalination facility cost?
Will my water bill increase if you build a desalination plant?
Will the plant be owned by local utilities or owned by a private company?
Are you involving the public in the project?
How is public comment being used?
Are there any other seawater desalination plants in the United States?
Why don’t you tap water from the freshwater springs off Crescent and Fernandina beaches?
What led to the decision to pursue seawater desalination?
What is seawater desalination?
Seawater desalination is an advanced treatment process used to remove dissolved salts and minerals from seawater to produce a high-quality drinking water. Seawater desalination is a drought-proof alternative water supply that can be produced in an environmentally sound manner.
Which local governments are investigating seawater desalination as a possible drinking water source?
Palm Coast, DeLand, Leesburg and St. Johns County are working together to investigate the feasibility of a seawater desalination plant in the Flagler County region. The project is being funded by the participating local governments and the St. Johns River Water Management District through the end of the current phase.
Why is desalination needed?
Most of the water currently used in this region comes from fresh groundwater supplies. Fresh groundwater alone will not be able to meet all future needs. Future groundwater withdrawals in the region will be limited to protect the environment and ensure a sustainable resource. Recent demand projections show that the project participants will need 10-15 million gallons per day (mgd) of new drinking water by approximately 2020. In order to meet future demand, alternative water supplies, such as seawater desalination, brackish groundwater, surface water and reclaimed water, must be developed. Seawater desalination is being investigated because it is a drought-proof alternative and because of the project participants’ proximity to the coast.
Instead of pursuing desalination, can’t we just conserve more water?
Conservation and reuse are essential and remain important components of each partner’s water supply planning. The project participants’ goal is to conserve and reuse their way to the smallest alternative water supply project possible as late as possible. Conservation and reuse can extend existing water supplies and reduce demand, but alternative water supplies will still be needed to protect groundwater resources and meet future drinking water needs. A sustainable, reliable water supply will require aggressive conservation, use of reclaimed water for irrigation and industrial purposes, plus new, alternative water supplies.
What is involved in the Coquina Coast Project?
The Coquina Coast Seawater Desalination Project is investigating the feasibility of a seawater desalination plant in the Flagler County region. The project is being implemented in phases, with numerous studies and analyses being conducted to progressively narrow the project down to a specific size, location and design. The first phase work included collecting data on raw water quality, developing finished water quality goals, determining plant size based on future water need projections, determining permitting requirements, analyzing site locations, public outreach, preliminary cost estimates and more.
The second phase work includes conducing additional water quality analyses and environmental assessments, pilot testing of treatment processes, siting the facility and pipelines, developing a preliminary design and cost estimates for plant construction and operations, and public outreach.
When is desalination needed?
Recent projections of future water needs show alternative water supplies will be needed in approximately 2020 to protect groundwater resources and meet future demands. These projections are subject to change as forecasts and project participants change. Work is ongoing because it can take up to 10 years or more to design, permit and construct large-scale, regional alternative water supply projects.
What is the project’s schedule?
Phase 1 of the project was completed in January 2010. Phase 2 is divided in Phase 2A and Phase 2B. Phase 2A is currently underway and includes preliminary plant siting, field investigations, permitting investigations, pilot testing planning and public outreach. Phase 2A is scheduled to be completed in September 2011. Phase 2B, which has been rescheduled to start in approximately 2014 or later, includes facility siting, preliminary design, pilot testing of treatment alternatives, public outreach and preparation of a National Environmental Policy Act document. If the project moves forward, it is slated to produce drinking water by around 2020.
Is the project dead?
No. While the economic recession has slowed growth and the need for new water, alternative water supplies will still be needed in the future. The Coquina Coast project partners have decided to slow the project’s schedule to save money during this difficult economic time. Pushing the next phase of work out for approximately two years allows time for the economy to stabilize, which will provide a better indication of future water needs. Should the project schedule slow further, the work done to date is still useful and provides a strong foundation for future investigations and analyses.
How much water will the facility produce?
The ultimate plant size will not be known until the end of Phase 2B, when local governments decide whether to participate in the project. Based on current projections, the initial capacity of the Coquina Coast desalination project is likely to be 10-15 mgd in 2020 with infrastructure sized to accommodate future expansion to approximately 25 to 50 mgd by 2050. Designing the plant for future expansion ensures adequate supply while delaying additional capital costs until the new supply is needed.
Who will receive the desalinated water?
Water from a desalination facility would be delivered to local governments that move forward with the project, and the ultimate project participants won't be known for about two to four years, depending on the economy. Desalination seawater would be blended with other water supplies before being delivered to the utility’s customers.
Are there economies of scale in building and operating a desalination plant?
Yes. Essentially, the larger the plant, the lower the unit cost of desalinated water. The reason is that there are costs that are relatively constant, no matter how much water a plant produces, e.g. permitting, land, intake and discharge construction, etc. Also, larger plants can take advantage of more efficient energy recovery devices to reduce power costs.
Why not limit growth? Wouldn’t that solve the water problem?
Even with the current economic recession and the subsequent impact on water demands, alternative water supplies will still be needed in the future in order for local governments to meet their legal obligation of providing drinking water to current and future customers. As the economy recovers and the need for water increases, so will the need for new alternative supplies. Each local government is responsible for managing growth within its jurisdictional boundaries and can establish land use standards and ordinances that conserve and minimize water use.
Is seawater a safe source of drinking water?
Yes. Seawater desalination produces some of the highest quality drinking water in the world. This project has established water quality requirements that meet or surpass state and federal drinking water standards. The goal is to provide the participants with high-quality water that requires little, if any, additional treatment before being blended with other water supplies. Phase 2 of the project includes pilot testing of treatment processes to ensure that the established water quality requirements will be met.
What process will be used to desalt the seawater?
The Coquina Coast project will likely purify seawater using reverse osmosis (RO), which uses high pressure to force seawater through a semi-permeable membrane. The membrane removes salt from seawater to produce fresh drinking water. RO is a proven technology in many plants operating throughout the world. The project team will also investigate emerging technologies if they meet specific criteria.
How much seawater does it take to make 10 to 15 million gallons of drinking water?
Given the salinity of the Atlantic Ocean, it is estimated that the each gallon of seawater treated will yield 40-45 percent drinking water, leaving 55-60 percent concentrated seawater. Given that recovery rate, the plant will be designed to treat two-and-a-half times the capacity of drinking water needed. It would take 25 mgd of seawater to produce 10 mgd of drinking water. It would take about 38 mgd of seawater to produce 15 mgd of drinking water.
Is the Intracoastal Waterway being considered as a source for the plant?
No, the Intracoastal is not being considered as a direct intake source for the plant.
What are beach wells and why are they being considered as a source for the plant?
Beach wells are wells installed near the shore that extract saline water from the ground. The wells may also pull in, or induce, seawater through the ocean floor. Saline groundwater is of higher quality than seawater pulled directly from the Atlantic Ocean because the sand acts as a natural filter, removing silt, organisms and suspended particles from the water. Beach wells are being considered because initial investigations show the availability of high-quality saline groundwater, which would yield a number of benefits to the project, including:
- Lower construction costs since an intake pipeline and structure on the ocean floor are eliminated
- Lower capital costs since high-quality saline groundwater requires less pretreatment systems
- Lower operating costs since less pretreatment is required
- Reduced impacts to marine life associated with construction and direct intake
- Easier construction for onshore wells versus an offshore pipeline and intake
What were the initial beach well investigations?
The Coquina Coast project team conducted screening level aquifer testing evaluations at the Marineland facility. Marineland is not being considered as the site for future beach wells, but its existing supply wells provided an opportunity to gather information that is representative of conditions in the Coquina region’s coastal aquifer system.The testing measured aquifer drawdown as well as a number of water quality tests. Test results overall were positive, indicating sufficient quantities of saline groundwater that was of higher quality than the Atlantic Ocean. While the initial screening level results are promising, additional testing needs to be conducted to determine the potential yield of beach wells and to quantify the costs and benefits of this intake option.
Are beach wells installed directly on the beach? What size are the wells and what would they look like?
Beach wells would not be installed directly on the beach, but rather on the beach ridge. Above ground, would be a caisson that is approximately 13 feet in diameter. A caisson is a watertight chamber that would surround the wells. A caisson can be camouflaged to fit into its surroundings. From the caisson, lateral arms would be installed under the beach.
How does the aquifer from which the beach wells would take water differ from the freshwater aquifer?
The aquifer from which beach wells would withdraw saltwater is separate from the freshwater aquifer that provides drinking water. Wells located on the beach ridge would have radial arms that collect water from the saltwater aquifer beneath the ocean. Additional aquifer testing is recommended in the next phase of the project to determine the potential yield of beach wells and to quantify the costs and benefits of this intake option. Should beach wells be the preferred intake method, monitoring wells would be installed to ensure there are no adverse impacts on the freshwater aquifer.
What chemicals will be used to treat the water and how safely will they be stored?
The pretreatment and post-treatment processes have not yet been selected and will determine what chemicals are added to the water before or after desalination. In general, desalination plants use chemicals similar to those of a traditional surface water treatment plant. Any chemicals used would be stored safely in accordance with all local, state and federal regulations.
How do you dispose of the leftover concentrated seawater?
The exact disposal method that will be used for this project has not yet been decided, but typically the nearly twice-as-salty seawater is returned back to the environment. Computer models and scientific studies will be used to examine viable options and determine the best method for mixing and dispersing the concentrated seawater.
One of the main concerns associated with a desalination plant is the effect of discharging the nearly twice-as-salty seawater back into the environment. The project team will examine various options and conduct computer models to help design the best method for mixing and dispersing the concentrated seawater. Desalination will be pursued only if studies show the environment will be protected.
Additionally, if the plant is built, safeguards will be put in place to ensure the salinity of the concentrate is within permitted limits prior to leaving the plant, and permit conditions will require monitoring to assure continued safe operation.
Is seawater desalination safe for the environment?
Seawater desalination can be done in an environmentally sound manner. Protecting Florida’s natural systems and coastal ecosystem is paramount to the project participants. That’s why a number of scientific studies will be conducted to assess whether seawater desalination is a suitable choice for the project participants.
One of the main concerns associated with a desalination plant is the effect of discharging the nearly twice-as-salty seawater back into the environment. The project team will examine various options and conduct computer models to help design the best method for mixing and dispersing the concentrated seawater. Desalination will be pursued only if studies show the environment will be protected. Additionally, if the plant is built, safeguards will be put in place to ensure the salinity of the concentrate is within permitted limits prior to leaving the plant, and permit conditions will require monitoring to assure continued safe operation.
Could the salt concentration be available for commercial processing to produce a dried salt product?
Several studies have been done in the past to examine the economic value of concentrated seawater. Existing technologies to evaporate the concentrate to derive sea salt and other minerals are energy intensive and not economically viable.
Will a desalination facility affect fishing or shrimping in the area?
Before a facility can be permitted, a number of scientific studies will be required. A plant will only be permitted if those studies show that marine life will be protected. Those studies will be conducted later in Phase 2, once the project is better defined.
Will pipelines on the ocean floor prohibit the use of fishing nets?
The project partners are as concerned about protecting the commercial, economic and recreational interests of the area as they are eliminating any potential environmental impacts. The use of fishing nets, boating interests and other factors will play a significant role in the evaluation of project alternatives.
Will a desalination plant affect the Northern Right Whale habitat?
No. The primary concern associated with the desalination plant and the Northern Right Whale is construction in the calving ground and impacts to migratory patterns. Construction activities, should they occur in the habitat, will be scheduled around calving season using methods of construction that do not impact the whale habitat.
Will red tide affect a desalination plant?
Red tide, algae and other organic materials can have an adverse effect on a desalination plant’s operations, which is why water quality and pilot scale testing are so important. The project team will perform a number of tests aimed at designing treatment processes with operational flexibility to respond to a variety of raw water quality challenges.
Would an oil spill like the one that occurred in Gulf of Mexico affect the desalination plant?
Any kind of oil, fuel or chemical spill in the vicinity of a desalination plant intake would prompt concerns. If such an event were to occur, water managers would protect the facility by closely monitoring movement of the contaminant and shutting down plant before anything could reach the intake.
Will there be marine impacts in the vicinity of the concentrate discharge?
No. Many scientific studies will be done to design the concentrate dispersal system. Previous studies and designs on similar projects around the world have shown no impact in the dispersion area. In fact, the dispersion structures have become man-made habitats for many species once thought to be the most susceptible to even minute changes in salinity.
How much energy will the plant use and does FPL have surplus energy available?
At a capacity of 25 million gallons per day, the Coquina Coast Desalination Plant will use approximately 15 megawatts of power. At the projected initial capacity of 10-15 million gallons per day, the power requirement is approximately 8-10 megawatts. During initial discussions with FPL representatives, they indicated that there is sufficient power generating capacity in the region to serve such a demand, so there would not be a need to construct a new power plant to serve the Coquina Coast Desalination Plant.
What wil be done to minimize the carbon footprint or to utilize alternative energy sources for this facility?
The Coquina Coast Desalination Project is likely to receive its power from the Florida Power & Light (FPL) grid, so the power source will include any power-generating facility that supplies the grid. The project team is committed to exploring the viability of alternative energy and has talked to FPL about alternative energy options and will continue to monitor FPL's progress. Additionally, the project design can reduce the overall carbon footprint by including efficient energy recovery devices which can reduce energy costs as much as 40 percent or more. The design may include other green energy alternatives, such as on-site solar panels for lighting and building power.
How large will the plant be? How much land do you need?
A desalination facility would require approximately 25-50 acres of land for pretreatment, reverse osmosis, post treatment and on-site storage facilities. This size parcel would also accommodate future expansion.
The siting process to-date has identified 14 areas in Flagler County that may contain sites suitable for the proposed desalination plant. These locations were identified after evaluating several larger areas in the region against the project's siting criteria, which were developed with community input. The 14 areas will be further evaluated in the next phase of the project.
Will the plant blend with the surrounding community?
We understand that preserving the beauty of the coast and consistency with surroundings are important to the community. Any facility will be sited and developed with public input to ensure community’s values are reflected in the location and appearance of the facility.
Will the plant be noisy?
If a plant is built, there will be some noise associated with the heavy equipment needed during construction. Once operational, however, it will be very quiet, similar to a typical surface water treatment plant. Buildings will buffer any noise from equipment located inside, such as the pumps needed for the reverse osmosis process.
Will the plant have an odor?
No, there will be no discernible odor from a seawater desalination plant.
The exact cost of the facility will not be known until the facility is designed. An engineer’s opinion of probable construction costs and associated assumptions estimates the capital cost of a 10-15 mgd plant between $180 million and $234 million (net present value). However, the exact cost of the facility and associated pipeline will not be known until the facility is designed.
Will my water bill increase if you build a desalination plant?
If a water utility commits to receiving desalinated seawater, it will likely increase customers’ water bills, but the amount of an increase will depend on a many factors, including the ultimate size of the facility, the extent of the distribution pipelines and so on. The single factor that may most affect the water bill will be the amount of desalinated seawater a utility receives from this project compared to water from other sources. Until the project is better defined, it is difficult to estimate which water utilities will see an increase and the amount of that increase.
Will the plant be owned by local utilities or owned by a private company?
Plant ownership is not yet known. The facility could be owned by a local utility or utilities, privately owned and operated, owned by a local utility and operated by a private entity, or some other arrangement. Ownership and operating options will be fully explored in Phase 2B.
Yes. Monthly business meetings and teleconferences have been open to the public. Stakeholder meetings were held in April 2009; public meetings were held on Sept. 29, 2009, March 9, 2011, and Aug. 17, 2011, at the University of Florida Whitney Laboratory at Marineland. While the project is on hiatus, residents can stay still follow any project news on Twitter at www.Twitter.com/CoquinaDesal and on the project web site, www.coquinacoastdesal.org.
How is public comment being used?
Public comment is being used to ensure the project reflects the community’s values. In addition, public input has and will continue to play a role as a selection criterion. The project participants agreed to equally weight the four selection criteria: Community Acceptance, Environmental Stewardship, Project Reliability and Permittability. The equal weighting is a strong statement that the community and the environment are just as important as reliability and the ability to secure necessary permits.
These criteria were used to make a decision regarding a land-based or vessel-based facility. Additionally, public input helped shape the siting criteria and were used as weighted scenarios to determine the short list of site areas. Public input will be used in other project decisions should the project move forward.
Are there any other seawater desalination plants in the United States?
The only large-scale seawater desalination plant currently operating in the United States is the Tampa Bay Seawater Desalination Plant near Apollo Beach. That plant can produce up to 25 mgd. There are other desalination plants being built in California and Texas. Across the globe, brackish water and seawater desalination plants in municipal, military and industrial applications produce a combined daily capacity of more than 18 billion gallons. Large-scale seawater desalination plants are currently operating in Spain, Trinidad, Israel, Singapore, Chile, Australia, China and Saudi Arabia.
Why don’t you tap water from the freshwater springs off Crescent and Fernandina beaches?
Tapping offshore springs has been studied, but the springs do not produce the quantity of water that is projected to be needed in the future. Additionally, the water still contains a significant salt concentration and would require some level of reverse osmosis treatment. However, the project team is investigating whether it would be advantageous to locate this project’s intake near an offshore spring to benefit from the lower salinity.
What led to the decision to pursue seawater desalination?
Seawater desalination was one of several alternatives identified in the Flagler County Water Supply Plan. This plan was developed under a Memorandum of Understanding among the St. Johns River Water Management District and 13 water supply entities in Flagler County. The plan was developed from April 2005 through September 2007 with input from the participating entities and public comment.
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