Letter to
Florida Keys Aquaduct Authority from Tom Rooney
Date: January 31,
2005
Thank you for the
information we received during our meetings on Jan 24
and Jan 26 and on the email exchanges.
As I understand it you
plan to go ahead with a design/build approach for the
three utility systems all bundled together.
1. Potable Water
Transmission and Distribution System
2. Wastewater
Collection System
3. Reclaimed Water
System
You outline in the
preliminary bidding documents a combined wastewater
collection system that has a vacuum system in Center
Island and gravity systems on the other three islands
that make up the residential islands of Duck Key.
I am concerned about
some aspects of this approach and will make
recommendations for change.
A. Wastewater
Collection System
Your position is that
the vacuum system is generally economical except for
the effect of the 10' elevation of the barrel bridges.
These bridges would require an additional vacuum
station at each bridge and that cost is $1MM bridge
vacuum station. You have dismissed initially the low
pressure system because it cannot function in the case
of a power outage. Thus you have gone to a combination
of the gravity system in three of the four islands of
the project (Harbor, Yacht Club and Plantation) and a
vacuum system on Center Island..
A gravity system is
not suitable for the conditions on the three large
islands at Duck Key. It could be suitable for Harbor
Island because trenching is in sand. We have hard,
fractured, porous rock on the three large islands that
make excavation very expensive. The ground water
varies with the tide but is between 3' and 4' below
the road surface. A pump test would confirm the amount
of flow to be expected and that flow would be
substantial. Your initial concept was to have the
gravity pipe depth limit at 8' max. At this depth the
contractor has a high risk even with a pump test and
an unknown without one. Besides the cost issue the
inconvenience to the residents is an issue. We
recommend abandoning this gravity system concept as
not economically viable. There is no reason to abandon
the potential of the gravity system. Depending on the
method of project delivery, the design builder, or the
designer will need to make a determination of what
system may be more capital cost effective. Perhaps
they will land on the vacuum system however, as we
have found the costs of the vacuum and pump stations
(VPS) to be so expensive, the gravity system may have
merit based on capital costs; now along with
operational costs.
With up to three
potential VPSs in the system because of the existing
conditions (mainly bridges) by the way, there is not a
VPS proposed at the WWTP), a vacuum system may, or may
not be the most cost effective. Also depending on the
form of project delivery, perhaps the design build
team may find that they can lift vertical 13-feet that
would reduce the number of VPS.
I maintain that the
marketplace should determine the cost effectiveness of
the system; not to arbitrarily abandon an acceptable
potential.
The vacuum system will
have some pipe below the ground water at the
infrequent 5' depth and that will add some expense but
nothing like the gravity system. We think this should
be studied as a system throughout the islands with a
vacuum station in the center of each island but using
a force main back to the treatment plant not an
additional vacuum station. It is possible to leave
Harbor Island on gravity because of the sand. When the
nearby residents see a rendering of the Vacuum
Stations with a security fence around it and the fact
that the generators will be noisy you can expect some
feedback. In a vacuum system you have to factor in the
acquisition costs, as well as public acceptance of the
VPS. We have had major opposition to site acquisitions
for utility projects in the near past. In this case,
it would be very helpful for the Duck POA residents to
be at the vanguard in identifying VPS locations, and
prepping the neighbors to dispel the rumors about
VPSs.
A low pressure
collection system should be studied as a possible
alternative. At this point we very well may consider
its use due to the extremely, often ridiculous high
capital costs. In addition, as explained, Duck Key
frontages are much greater than typical keys lost
hence the amount of pipe per EDU increases by close to
50%, and in Duck Keys case, the development is only
about 50% built out. So, in effect, the system will
just about need to be constructed for all 700 lots
when only about half are being served.
Keep in mind that the
monthly operational costs of the grinder system will
be much greater, mainly individual pump operation and
repair however, if the Duck Key residents don't care,
this system does have merit. Also, it would be very
helpful for the Duck POA residents to again be at the
vanguard in telling residents of the need to provide
blanket easements on their property for the operation
and maintenance of the grinder systems, and dedicate
the area and utilities for the system. These issues
will greatly assist in implementing this type of
system.
3.1
The low pressure
system does in fact have some storage capacity in the
case of a power outage. Depending on the vendor chosen
it can provide up to 100 gal. of storage if you do
nothing more than use their standard equipment. With
the power out you can't work your dish washer and
clothes washer so this should be enough for one days
storage per household. In the case of a hurricane
where we could be out for a week or so the following
would be the situation. The vendor will have provided
a plug-in connection for a generator and the owner can
hook in if he has one. Alternately additional standby
capacity can be economically provided by increasing
the size of the service pipe from the house to the
pump grinder tank or by adding a plastic tank in that
line. The inverts would have to be such that effluent
wouldn't store under normal operating conditions. This
could be enough to provide storage for a week under
the conservation conditions in place after a
hurricane. The homeowner can decide to get the
additional capacity through a generator or through
storage or they may decide to do nothing. Remember
only 25% of our residence are in the Keys during the
riskier hurricane months. Most of them would leave
also when ordered so we are only talking about 30 or
so families that would be affected.
3.2
Maintenance and
operating costs should not be an issue on this system.
Typically the electric bill is $25 to $35/year for the
pump/grinder unit. The pump grinders often go years
without requiring any attention.
One vendor claims
their mean time to service a pump grinder unit is 8
years.
The units are light
enough for one man to remove it and then replace it
himself in an hour. Vendors recommend that the utility
own and maintain the units instead of the
homeowner.
3.3
The initial installed
cost of the pump/grinder station is less then
$4,000//unit for our quantity. Sometimes they can put
two houses on a unit but they only recommend that if
the utility owns the pump grinders. The cost of the
collections system is where the savings are realized.
The pipe will generally be 3' down and above the water
table and often without rock.
Because the sewage has
been ground the pipes are small. The costs are
comparable to a water distribution system as you have
a lot of freedom in locating the pipe. They typically
lay it with reels of rolled (900') HDPE pipe. Because
of the fewer joints in the pressure system compared to
the gravity system and vacuum system you have a much
tighter line over time.
3.4
This system has been
around for many years and is proven. It is especially
appropriate in hard rock and groundwater conditions.
It is installed at Key West Naval Air Station and
Sunset Key. It may be a solution for you in other
parts of the Keys also.
Summary: I would like
to see the total vacuum system and the low pressure
system studied conceptually to determine the best
solution for Duck Key on the basis of Present Value.
Once the best system is determined the project then
can go forward with the one system into the design
build phase.
B. Contracting
Methods
You have discussed two
methods of proceeding: Design Build Detail Design,
Lump Sum Bid and Construct
Before a decision is
made on a Design Build concept a survey has to be made
to determine how many competent bidders will actually
bid the project You may have done this already. The
key word here is competent. With the three piping
systems the bidder has to do some design to bid it
This will limit the number of bidders either because
of cost, sophistication or concern about award. If you
canít get 4 or so bidders to commit to respond
you shouldn't go Design Build. If you only have two
bidders you may not really have a competitive
situation although you might think you do. If you are
assured of competent competitive bidding the Design
Build approach is good.
If you can't then you
should do a complete design and get competitive Lump
Sum bids. You will no doubt get competitive bidding in
that second scenario as there are a lot of lump sum
contractors for this amount of work.. We are
discovering that design build may reduce the amount of
bidder/proposer participation. In addition, the
process does not appear to expedite the project
delivery; in fact it could slow it up. Although we are
expediting the City of Layton project through D/B, it
is a small project and was actually assisted by having
only one Proposer; a unique situation. Because there
is some much pipe in this project, the project in my
opinion lends itself to a design, bid, and build
project delivery. I believe in this case, the number
of bidders will increase because of the project
volume. Keep in mind that this is low price work, and
sometimes low price is what you get.
One reason we
considered a design build qualifications based project
delivery process.
Crawl Key
Alternative
You have just opened
bids on a major treatment plant on Crawl Key. This
plant is correctly located on an island that is
sparsely populated.
Conceptually why are
we overhauling the Hawks Cay plant for use when all of
the sewage (Conch Key, Hawks Cay and Duck Key) can be
sent to the Crawl Key plant? Is it not a better use of
our collective resources to demolish the Hawks Cay
plant, clean it up and use the property for the best
available use? I haven't seen the most current
operating figures on the Crawl Key plant. If the cost
per gallon treated there is comparable to Hawks Cay
you should study the concept of pumping the sewage to
Crawl Key. The accrued value of the pristine piece of
property under the plant should offset the cost of
routing the sewer line and the required reuse line to
Crawl Key. We need some long term thinking about what
is best fore our collective communities. I request a
study of the economics of taking the sewerage to Crawl
Key and closing the Hawks Cay plant. I believe you
just got the economics of going to Crawl Key from the
recent Marathon Cost Proposal. It appears that the
WWTP costs for that project will be equal or possibly
significantly greater than the upgrade to the
Hawkís Cay WWTP. Based on the recent equation
for the design and build of the Hawkís Cay WWTP
upgrade, the unit cost of ~ $10 per treatment gallon
has been established. We will receive the itemized
costs of the Crawl Key WWTP however, I highly doubt
that that the unit cost will rival the Hawkís
Cay quote. Also, waiting on the Marathon decision
could take a while that could jeopardize the Duck Key
in the Hawks Cay option.
I write this memo as a
resident of Plantation Island of Duck Key not on
behalf of any organization. I am concerned about
future sewer costs, unnecessary excessive interruption
in life style and government waste.
I would appreciate a
response as soon as practical.
Best
regards,
Tom Rooney
