Why Desalination? Q A

Why Desalination?
Q
A
Why do we need a desalination facility?
Q
A
Who will benefit from this plant?
Q
A
Has desalination worked in other areas?
Q
How does the planned desalination facility compare to other facilities as far as overall
capacity?
A
IDE’s Carlsbad, California’s desalination facility will produce 50 million gallons of water per
day. The La
¯na‘i facility will start by producing 2.5 million gallons per day and increase to 5
million gallons per day in the next expansion phase.
Q
A
What’s the cost of the facility and how will you get back the money you invested?
Q
A
What is the life of the installation?
Fresh water makes it possible to undertake the developments needed for a sustainable
La
¯na‘i. If the island stays as it is, without any additional fresh water, La
¯na‘i and its
economy will remain stagnant. For young people to return to live and work on La
¯na‘i, we
need to develop an economy that creates jobs and makes it possible to build homes and
grow food for them. Pu
¯lama La
¯na‘i’s goal is to create a model of sustainability, and the
availability of more water is key to making this happen.
The people of La
¯na‘i will be the ultimate beneficiaries because the facility will reduce
reliance on the islands aquifer. Along with protection of the watershed, reducing reliance
upon the aquifer should enhance water security for the island.
Desalination facilities have been operating successfully across the world for more than 40
years and include a number of islands that use desalinated water as their only potable
water source.
La
¯na‘i needs water. For La
¯na‘i to grow and realize a sustainable vision, a second reliable
source of water must be developed, in addition to the high-level aquifer. At this stage
of the project, Pu
¯lama La
¯na‘i has not identified all of the costs, but is making this capital
commitment to help support the vision of achieving a sustainable La
¯na‘i.
Although there is a life span for pumps and membrane filters, a normal maintenance and
parts-replacement program will keep the desalination facility operating for a long time to
come.
Understanding the Process
Q
How will the concentrate (hypersaline water) from the desalination facility go back into
the ocean? Will it affect the ocean ecosystem?
A
The desalination plant will utilize saline groundwater as its feedwater supply. The saline
groundwater will be drawn from depths that are well below the thin and brackish
basal lens so as not to disturb the lens itself. The salinity of this feedwater supply will
be essentially identical to seawater. About 42 percent of the feedwater will be the
desalinized product water for drinking water and irrigation use. The salts removed from
the product water will be in the remaining 58 percent of the feedwater, referred to as the
concentrate. Although Pu
¯lama La
¯na‘i is investigating possible uses of the concentrate,
it will initially, at least, be discharged into disposal wells at depths between 150 to 400
feet below sea level. The concentrate will be about 1.8 times as salty as sea water. It will
first go into disposal wells and will then diffusively discharge into the ocean at a depth
substantially greater than 400 feet below sea level and more than two miles offshore.
The salt added to the concentrate will make it heavier than saline groundwater or
seawater. This means it will tend to sink deeper rather than rise as it moves from the
disposal wells toward the ocean. From the time it enters the wells until it is diffused into
the ocean offshore, preliminary studies indicate it will take two or more years for it to
travel from the disposal wells through the bedrock and into the ocean. Mixing into saline
ground seawater along this lengthy travel path will mean that when it reaches the ocean
it should have about the same amount of salinity as the ocean water, so it should have no
effect on the ecosystem.
However, Pu
¯lama La
¯na‘i is also performing offshore monitoring to ensure the accuracy
of the preliminary studies. Baseline marine data has already been collected, and will
continue to be collected, to describe the existing baseline conditions inside and outside
of Hulopo‘e Bay, in Ma
¯nele Harbor, and the area downslope from the disposal wells
before the initiation of the desalination project. Comparing this baseline to data collected
after the desalination project is operating will reveal if the project is resulting in changes
to water quality within the survey areas.
Q
What will be going into the ocean and where? If concentrated salt water is going into
Hulopo‘e Bay, will it disturb the marine life?
A
The concentrate disposal wells are about 1 mile west of Hulopo‘e Bay. This location is
also down current from the bay, so no concentrate will be flowing into Hulopo‘e Bay. The
salinity of the concentrate is denser than seawater so it will sink and diffuse as it travels
through the bedrock to the ocean. By the time this water comingles with the open
ocean, it will be of essentially the same salinity, so there will be no effect on marine life at
the point of entry.
Q
A
Why not use brackish water since it contains less salt?
Pu
¯lama La
¯na‘i has made the decision to use saline groundwater rather than the brackish
basal lens so as not to change the discharge of groundwater into Hulopo‘e Bay. However,
the reality is that the amount of flow in the basal lens is very modest. Over a period of
time, wells attempting to tap the basal lens would see the pumped water salinity rise and
approach that of seawater.
Q
When the concentrate is put into the disposal wells, will it raise the temperature of the
ocean water? Has there been any testing of water quality or temperature?
A
Results from the first two supply wells establish that the saline groundwater delivered
to the desalination plant will be 78° to 79° F. The desalination process will increase
the temperature of the discharged concentrate by less than one degree over that of
the incoming feedwater. Results from the first of the disposal wells indicates that the
temperature in the receiving saline groundwater is between 77° and 78° F, possibly one to
two degrees cooler than the delivered concentrate. As the concentrate mixes with saline
groundwater over its more than two year travel time to reach the marine environment,
both its salinity and temperature will be decreased to ultimately become essentially
identical to those levels in the receiving saline groundwater body.
Q
A
What is meant by “Pre-Treatment”?
Q
What is the Post treatment noted in the Desal process. Is it poison being put in the
drinking water?
A
Post-treatment consists of pH adjustment with carbon dioxide followed by the addition
of calcium carbonate into the product water. This process also reduces the corrosion
affect the water would otherwise result in pipes. This is also described by the Langelier
Saturation Index (LSI). The additives are non-hazardous and non- toxic.
Q
A
What other chemicals are used in the drinking water?
Pre-Treatment can consist of a multi-media filter which removes particles greater than
75 microns (or 0.075 milimeters) and a cartridge filter to remove particles greater than
10-microns prior to entering the RO element array. The pilot testing will determine the
exact pre-treatment needed. All chemicals that may be used in the pre-treatment process
will have National Sanitation Foundation (NSF) 61 certification and are allowable to be
used in drinking water and are environmentally safe.
In accordance with the EPA and State Dept. of Health (DOH) drinking water regulations,
hypochlorite (bleach) is added to provide residual chlorine in the potable water to kill any
microbial growth in the water. This is the same process used with current potable water
from our drinking water wells in La
¯na‘i City.
Why Liquefied Natural Gas?
Q
A
What is the role of MECO in the desalination plant?
Q
Why do you need Liquefied Natural Gas (LNG) for the power plant and how will it be
brought to La
¯na‘i and stored?
A
Through Hawaii Gas, Pu
¯lama La
¯na‘i will be shipping in 40-foot ISO containers of LNG
from the West Coast to fuel the desalination facility. These containers will be stored in a
secured area in the Miki Basin area. Empty containers will be shipped back to the West
Coast for refilling. The supply of LNG containers on island will be sufficient to cover the
Since MECO is not able to provide all of the required power, Pu
¯lama La
¯na‘i will be
developing a source independent of the MECO grid and will work with MECO to integrate
renewable energy sources to supply power to the facility.
demand for an extended period, even if two barge cycles are missed.
The desalination plant will have state-of-the-art detection systems that identify hazardous
situations and automatic shutdown systems that halt operations in cases of emergency.
Q
A
Why LNG? Were other fuels considered?
Pu
¯lama La
¯na‘i will explore all options for renewable energy, including mini-wind, also
called community-scale wind, solar, waste to energy and other emerging technologies.
However, these are not expected to be able to be permitted and developed in time as an
immediate source of power for the desalination facility.
Pu
¯lama La
¯na‘i would like to assure residents that there will be no nuclear power.
Additional information on LNG related to safety and benefits can be found on Hawaii Gas’
website – www.hawaiigas.com .
While Pu
¯lama La
¯na‘i continues to research and plan for additional renewable energy
generation, LNG is the cleanest fuel alternative to develop the first phase of firm power
production for the desalination plant. It is also inherently safer to manage and transport.
It is the same fuel that MECO plans to use at the Miki Basin power plant in the future.
Where Does the Ground Seawater Come From?
Q
A
Why not draw water directly from the ocean?
Q
A
Do federal rules regulate water injection wells?
Q
A
What if a test well has problems?
Drawing water from the ocean would require that a large amount of particulate matter
from plants and marine life would have to be removed by pre-treatment prior to
desalination. Saline groundwater beneath the basal lens does not contain biomatter
as it has been filtered moving through volcanic rock. Drawing water directly from the
ocean would also require the construction of some form of pipeline extending from the
shoreline to a distance into the ocean where water quality would be acceptable.
Federal rules govern all types of disposal wells, including the type that will be used to
dispose of the concentrate. In Hawai‘i, the Underground Injection Control (UIC) program
of the State Department of Health implements the Federal regulations. Pu
¯lama La
¯na‘i
applied for and received the appropriate permit to construct and test concentrate
disposal wells. After the test results are submitted to the DOH UIC, a permit to operate
the wells will be issued.
Two production source wells have been successfully completed and tested and shown
to be able to provide a sufficient amount of water for the desalination project. A third
supply well will be constructed later in 2014 and its results are expected to be similar.
Similar testing will be done at stages of development of the disposal wells. If adequate
capacities are no obtained, the alternatives are to drill deeper or to construct an
additional well or wells.
Q
A
Will the desalination facility have any positive effect on the aquifer?
In theory, drawing less water from the aquifer should aid in its replenishment process.
However there are other factors that play into the process so we cannot state with certainty that there
will be a positive impact.
At the present time, the island’s total high level groundwater pumpage averages about 1.9 MGD. About
1.1 MGD of this amount is used for drinking water and golf and landscape irrigation at Manele. When
the desal plant is in operation, it will supply all the water use at Ma
¯nele. That means that use of the
high level groundwater will drop from 1.9 MGD currently to just 0.8 MGD with the desalinatin facility in
operation. This reduction in groundwater use will have a positive effect on the aquifer.
Q
A
What permits and studies are needed for this project?
Pu
¯lama La
¯na‘i submitted an Application for State Land Use Commission Special Use Permit and Project
District Phase 2 Approval with the County of Maui’s Department of Planning. A number of reports where
done to study the potential impacts of the wells and desalination plant. Pu
¯lama La
¯na‘i submitted to the
Planning Department and La
¯na‘i Planning Commission a project assessment report which summarizes
all of these reports.
Other Impacts
Q
A
Q
A
Are there other uses for brine besides salt, freezing or for packing fish?
Pu
¯lama La
¯na‘i is currently working with experts to identify other options.
What kind of jobs will the desalination plant create?
For the first two years, IDE will operate the facility. During this time, they will be training La
¯na‘i residents
to take over operations. The plant will employ 6 to 10 people.
Similar to other drinking water treatment plants, IDE will have an operating and maintenance manual
which will address DOH and additional safety regulations for the safe operating of the facility. This will
include emergency operating procedures of La
¯na‘i Water Company.
Q
A
What are the impacts of so many contractors?
Q
A
Q
A
All Pu
¯lama La
¯na‘i construction contractors are required to attend an Island cultural & community code of
conduct orientation to educate them on the uniqueness of La
¯na‘i’s way of life and natural resources and
environment. Clear expectations will be communicated to all contractor’s expected behavior and code
of conduct requirements. At the peak of construction for the desal plant, it is anticipated that 75 – 100
construction workers may be needed and commuting to La
¯na‘i from either Maui and/or O‘ahu.
How much noise will the plant make?
County zoning requires that noise levels be at or below 70 dba. Additional noise mitigation and sound
attenuation is being designed to further reduce noise levels.
What impact will desalination have on the land?
Impact to the land will be limited to the improvement of existing access roads, buildings and water
tanks.
Q
A
Q
A
Q
A
How does this affect our water rates?
Pu
¯lama La
¯na‘i has hired an independent company to look at the water rates for the
upcoming rate case mandated by the PUC. The PUC has required Pu
¯lama La
¯na‘i come
before the Commission by 2017 at the latest.
What permits and studies are needed for this project?
Pu
¯lama La
¯na‘i submitted an Application for State Land Use Commission Special Use
Permit and Project District Phase 2 Approval with the County of Maui’s Department of
Planning. A number of reports where done to study the potential impacts of the wells
and desalination plant. Pu
¯lama La
¯na‘i submitted to the Planning Department and La
¯na‘i
Planning Commission a project assessment report which summarizes all of these reports.
What about earthquakes?
All buildings will meet the Maui County building codes for earthquake and hurricane
stability.