Title: Desalting Water in Florida by Glenn M Dykes
CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/WL00004178/00001
 Material Information
Title: Desalting Water in Florida by Glenn M Dykes
Physical Description: Book
Language: English
Publisher: Journal AWWA
 Subjects
Spatial Coverage: North America -- United States of America -- Florida
 Notes
Abstract: Jake Varn Collection - Desalting Water in Florida by Glenn M Dykes (JDV Box 43)
General Note: Box 18, Folder 3 ( Treatments of Water - 1983 ), Item 2
Funding: Digitized by the Legal Technology Institute in the Levin College of Law at the University of Florida.
 Record Information
Bibliographic ID: WL00004178
Volume ID: VID00001
Source Institution: Levin College of Law, University of Florida
Holding Location: Levin College of Law, University of Florida
Rights Management: All rights reserved by the source institution and holding location.

Full Text


MANAGEMENT
AND
OPERATIONS








Desalting water

in Florida

Glenn M. Dykes

The scarcity of water resources of suitable quality for drinking
water near some of the most rapidly growing coastal com-
munities in Florida has made desalting a feasible means of
using brackish groundwater for potable supplies in many
areas. Reverse osmosis has proven to be the most satisfactory
and widespread technique for development of these alternative
sources of potable water.


Most Florida citizens and visitors to the state are
aware of its vast quantities of water and relative
abundance of rainfall, which constitute a cherished
resource. In view of this, the casual observer might
wonder why any desalting facilities are needed to satisfy
potable water demands.
Recent droughts, sinkhole formations, reduced lake
levels, and other water resource problems have concerned
those who thought the state had virtually limitless water
resources. Although there are enormous quantities of
water available, there are areas of the state where the
quantity and quality are not adequate to satisfy the
needs of the expanding population. The problem, then, is
one of managing water resources and using water of
lower quality in some areas. This article addresses some
of these management and water resource concerns.
Water resource considerations
Florida is now the seventh most populous state in the
nation with an estimated population of 10 million and is
one of the most rapidly growing states. Such develop-
ment, combined with the estimated 35 million annual
visitors, places considerable stress on the environment,
including the effects of developing an adequate supply of
potable water. To further complicate the availability of
potable water resources, most people moving into the
state have a strong desire to live along the vast coastline.
This depletes water resources in areas where sources are
least adequate to support additional stress and where, in
many instances, saltwater intrusion has occurred. Salt-
water intrusion is caused by overpumping the relatively
thin layer of freshwater overlying the saltwater, thus
allowing mineralized water to rise and increase the
salinity of water entering well casings.
The use of groundwater for expansion of agriculture,


L. ..




industry, and power generation to support the state's
growth has placed even greater stress on this resource.
The resulting effect is an overall lowering of the piezo-
metric levels in the principal statewide aquifer.
This is not intended to present a doomsday image,
especially in view of the annual average rainfall of 127
cm (50 in.) in the peninsular portion of the state.
Although much of the annual statewide rainfall, which
amounts to 189 TL (50 tril gal) a year, is lost through
runoff and evaporation, a great deal finds its way into the
aquifers and keeps them recharged. Daily consumption
for drinking water purposes approximates 5.6 GL (1.5 bil
gal). More than 90 percent of this water is supplied from
groundwater. To put this in perspective, the state's 22
first-magnitude springs, with flows of 2.8 ms/s (100 cfs)
or greater, discharge 13.6 GL/d (3.6 bgd) to estuarine
waters. These springs discharge water from the same
underground aquifers that supply potable water. Water
is available, but this background gives some idea of the
problem facing Florida's water resource planners.
Water quality concerns
Most of the state is underlaid with limestone that
stores large quantities of water. This water is satisfactory
for potable and domestic uses in most areas; however,
these uses constitute only a small fraction of groundwater
consumption since agriculture, electric power plant, and
industry withdrawals greatly exceed domestic demands.


104 MANAGEMENT AND OPERATIONS


JOURNAL AWWA







The city of Sarasota's treatment plant, shown below,
desalts 17 ML/d (4.5 mgd) of brackish water by reverse
osmosis to mix with 28 ML/d (7.5 mgd) of zeolite-
softened raw water for a total capacity of 45 ML/d (12
mgd). Shown on the left is the interior of Lee County's
Greater Pine Island plant where cartridge prefilters are
placed ahead of the 3 ML/d (0.825 mgd) reverse osmosis
units. The desalted water in this case is blended with
lime-softened water.


* '..2 ~.- *


,-.
-
4, .
m : "-" "
'*'*- ,; ~ -" .- -^ S l-
-^-.1- -.^ L"' _'. .^_,__<;i, ,;. '^'""t *J


Aside from limestone resources, several areas of the
state have shallow, unconsolidated formations that con-
tain adequate resources to meet domestic and other
demands. Portions of the deep-seated limestone forma-
tion are artesian, and some areas are also highly mineral-
ized. Open holes or improperly cased wells have per-
mitted these mineralized water resources to permeate
shallower strata in many areas.
The continuing pattern of growth in coastal areas
creates greater concern because more people are living in
water-poor areas. As population increases, more water is
needed to meet potable and domestic needs. This results
in a lowering of piezometric levels and an even greater
potential for saltwater intrusion. Some of the shallow,
unconsolidated formations along the coast have already
experienced such increased mineralization, as have some
of the deep-seated limestone formations. Thus it is
understandable that although water is available, it may
not be of suitable quality for potable use.
Meeting potable water standards
In view of the varied quality of water supply sources
and the possibility of obtaining highly mineralized
water, Florida's rules and regulations have always
contained aesthetic or secondary standards. These stan-
dards predated the Safe Drinking Water Act by, perhaps,
30 years. Until 10 years ago, it was difficult to obtain
compliance with the standards for total dissolved solids


(TDS), chloride, and sulfate because technology had not
advanced sufficiently to produce potable water quality
feasibly by reducing these constituents. But with current
desalting technology, it is possible to produce a suitable
water. Since the advent of such desalinization treatment
techniques, water quality deficiencies in many of the
older existing supplies have, to a large measure, been
corrected, or the system has been connected to larger
regional supplies that are in compliance with the stan-
dards. New facilities have had to provide this higher
degree of treatment for approximately the past 10 years.
In coastal areas, municipalities and developers have
used shallow groundwater resources to their ultimate
potential. Finding new resources that comply with
acceptable quality standards is difficult in some of these
areas. In the southern half of the state, artesian waters
have adulterated both the shallower limestone formation
and the water table aquifers. Although the artesian
formations may be creating part of the problem, they
may also provide some of the answers to meeting future
potable water demands. The mineral content in the zones
varies from 2000 to 7000 mg TDS/L and is treatable with
current technology. The problem is one of economics:
treat the mineralized water from sources along the coast
or transmit better-quality water from inland sources 32
to 48 km (20 to 30 mi) away.
Continued coastal development, combined with the
abundant source of mineralized water, has made Florida


MARCH 1983


G.M.DYKES 105


I


D~

e??~L~L~L~L~L~L~L~L~L~LI- -C~I









TABLE 1
Florida's desalting facilities


County Plant Names


Brevard
Brevard
Brevard
Brevard
Charlotte
Charlotte
Charlotte
Charlotte
Charlotte
Charlotte
Charlotte
Charlotte
Collier
Flagler
Flagler
Hendry
Hendry
Indian River
Indian River
Indian River
Indian River
Indian River
Lake
Lee
Lee
Lee
Lee
Lee
Lee
Lee
Lee
Lee
Manatee
Martin
Martin
Martin
Martin
Monroe
Monroe
Monroe
Monroe

Orange
Palm Beach
Palm Beach
Palm Beach
Sarasota
Sarasota
Sarasota
Sarasota
Sarasota
Sarasota
Sarasota
Sarasota
Sarasota
Sarasota
Sarasota
Sarasota
Sarasota
Sarasota
Sarasota
Sarasota
Sarasota
Sarasota
Sarasota
Sarasota
Sarasota
Sarasota
Sarasota
Sarasota
Sarasota

Sarasota
Sarasota
St. Johns
St. Lucie
St. Lucie
St. Lucie
St. Lucie
St. Lucie
St. Lucie
St. Lucie
St. Lucie
Volusia
Volusia
Volusia
Volusia
Volusia
Volusia
Volusia


KOA Christmas
Shelton Land and Cattle Co.
Okeelanta Sugar
Pheasant Walk (Palm Beach County System no. 6)
Bay Front (mobile home park)
Bay Lakes Estates (mobile home park)
Camelot Lakes (mobile home park)
Courtside Tennis Club
Englewood Water District*
Fairwinds Condominium Village
Heron Bay Club*
Kings Gate Club
Kings Gate Park (travel trailer)
Lake Village (mobile home park)
Lyons Cove Condominium
Myakka River State Park
Nokomis School
Palm and Pines (mobile home park)
Peterson Manufacturing
Pelican Cove (subdivision)
City of Sarasota
Sarasota Bay (mobile home park)
Siesta Key
Siesta Key
Spanish Lakes (mobile home park)
Sorrento Shores
Sorrento Shores (subdivision)
Southbay Yacht Club
City of Venice

Venice Ranch Mobile Home Estates
Workman Electronic Corporation
Mariner's Watch
Bryn Mawr Camp Resort
Fort Pierce lai Alai
Harbor Foundation
Miramar
Ocean Harbor South
Ocean Towers
Queen's Cove
Sand Dollar*
Hawaiian Tropic
Indian Harbor Estates
Kingston Shores
City of Ponce Inlet
Riverwood Park
South Waterfront Park
Terra Mar Village


Plant Manufacturer
Baic ehooy etPl ecF


*Not yet in service


JOURNAL AWWA


106 MANAGEMENT AND OPERATIONS


tput
mgd


TABLE 1
Florida's desolting facilities


Cove of Casseekee
Cove of South Beaches
Chuck's Steak House
South Brevard Utilities
Alligator Utilities
Burnt Stone Utilities
Charlotte Harbor Water Assn.
Eagle Point Nest (mobile home park)
Gasparilla Pines
Hunter Creek (mobile home park)
Rotunda West
Seaside Service System
Pelican Bay
1414 Mobile Home Park
Marineland
South Florida United Methodist Camp
Citrus Belle
Indian River County South*
Seminole Shores
Tropic Villas
Village Green
Village Green West"
Wekiva Falls Park
Cape Coral
Greater Pine Island
Gulf Coast Resort
Imperial Mobile Home Estate
lona Trailer Ranch
Sanibel Island Water Assn.
Sanibel Island Water Assn.
Sunset Captive (subdivision)
Useppa Island
Christian Retreat Camp
Indian River Plantation
Joe's Point
River Club
Sailfish Point
Aqueduct-Rock Harbor
Florida Keys Aqueduct
Florida Keys Aqueduct
Ocean Reef Club


Type of
Plant
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO (low pressure)
RO
RO
RO (low pressure)
RO (low pressure)
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
ED
RO
RO
RO
RO
RO
RO
RO
RO
RO (standby)
FD (standby)
RO
RO

RO
RO
RO
RO (low pressure)
RO
RO
RO (low pressure)
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
ED
RO
RO
RO
ED
RO
RO

RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO


I


Basic Technology. West Palm Beach, Fla.
Basic Technology. West Palm Beach. Fla.
Basic Technology. West Palm Beach. Fla.
Permutit. Paramus. N.J.
Polymetrics, Santa Clara, Calif.
Basic Technology. West Palm Beach. Fla.
Basic Technology. West Palm Beach. Fla.
Permutit. Paramus. N.J.
Permutit. Paramus, N.).
Permutit. Paramus. N.J.
Permutit, Paramus. N.J.
Gulf Environmental Systems. San Diego. Calif.
Permutit. Paramus. N.J.
Dupont, Wilmington. Del.
Permutit, Paramus, N.J.
General Atomic. Roga Systems Div.. San Diego, Calif.
Basic Technology. West Palm Beach. Fla.
Water Services of America, Milwaukee, Wis.
Basic Technology. West Palm Beach, Fla.
Dupont, Wilmington. Del.
Polymetrics. Santa Clara. Calif.
Polymetrics. Santa Clara. Calif.

Permutit, Paramus, N.J.
Envirogenics Systems Co.. El Monte. Calif.
Basic Technology. West Palm Beach. Fla.
Basic Technology, West Palm Beach. Fla.
Basic Technology. West Palm Beach. Fla.
lonics. Inc.. Watertown. Mass.
Hydranautics. Goleta. Calif.
Basic Technology. West Palm Beach. Fla.
Polymetrics, Santa Clara. Calif.
Polymetrics. Santa Clara. Calif.
Permutit. Paramus. N.J.
Basic Technology. West Palm Beach. Fla.
Basic Technology, West Palm Beach. Fla.
Basic Technology. West Palm Beach, Fla.
Fluid Systems Div., UOP. Inc.. San Diego, Calif.
Westinghouse. Pittsburgh, Pa.
Water Services of America. Milwaukee, Wis.
Gulf Environmental Systems and General Atomic,
Roga Systems Div.. San Diego. Calif.
Permutit, Paramus. N.J.
Permutit. Paramus. N.).
Dupont, Wilmington. Del.
Basic Technology. West Palm Beach, Fla.
Continental Products of Texas. Odessa, Texas
Dupont, Wilmington, Del.
Basic Technology. West Palm Beach. Fla.
Continental Products of Texas. Odessa, Texas
Hydranautics, Goleta. Calif.
Polymetrics. Santa Clara. Calif.
Emco Wheaton. Inc.. Conneaut. Ohio
Basic Technology. West Palm Beach. Fla.
Purification Sciences, Inc.. Geneva, N.Y.
Gulf Environmental Systems. San Diego, Calif.
Gulf Environmental Systems. San Diego, Calif.
Purification Sciences, Inc.. Geneva. N.Y.
Basic Technology. West Palm Beach. Fla.
Polymetrics. Santa Clara. Calif.
Continental Products of Texas. Odessa, Texas
Polymetrics. Santa Clara.-Calif.
Polymetrics. Santa Clara, Calif.
Polymetrics. Santa Clara. Calif.
lonics. Inc., Watertown, Mass.
Polymetrics, Santa Clara. Calif.
Gulf Environmental Systems. San Diego. Calif.
Permutit. Paramus. N.).
lonics. Inc.. Watertown. Mass.
Permutit. Paramus. N.J.
Polymetrics, Santa Clara. Calif. and
Basic Technology. West Palm Beach. Fla.
Dow. Midland. Mich.
Polymetrics. Santa Clara. Calif.
Permutit. Paramus, N.).
Gulf Environmental Systems. San Diego. Calif.
Permutit. Paramus. N.J.
Permutit. Paramus, N.J.
Basic Technology. West Palm Beach. Fla.
Basic Technology. West Palm Beach. Fla.
Basic Technology. West Palm Beach. Fla.
Basic Technology. West Palm Beach, Fla.
Basic Technology, West Palm Beach. Fla.
Dupont. Wilmington. Del.
Ajax International Corp.. San Diego. Calif.
Permutit. Paramus. N.I.
Permutit. Paramus, N.J.

Ajax International Corp.. San Diego. Calif.
Dupont. Wilmington. Del.


Ou
ML/d
0.075
0.037
0.018
0.302
0.113
1.362
1.703
0.136
0.378
0.151
1.892
0.037
1.892
0.170
0.378
0.037
0.003
9.463
0.075
0.227
0.378
0.503
0.056
18.927
3.122
0.105
0.363
0.075
7.949
5.678
0.064
0.102
0.075
0.189
0.454
0.227
0.567
3.785
9.463
11.356
3.936

0.052
0.015
0.158
4.088
0.007
0.162
0.378
0.003
1.892
0.162
0.037
0.227
0.227
0.022
0.022
0.189
0.003
0.034
0.001
0.454
17.034
0.018
7.570
2.365
0.227
1.514
0.378
0.776
11.356

0.075
0.001
0.060
0.567
0.147
0.071
0.151
0.378
0.454
0.037
0.378
0.162
0.302
0.567
1.491
0.011
0.056
0.162


_11 *


0.020
0.010
0.005
0.080
0.030
0.360
0.450
0.036
0.100
0.040
0.500
0.010
0.500
0.045
0.100
0.010
0.001
2.500
0.020
0.060
0.100
0.133
0.015
5.000
0.825
0.028
0.096
0.020
2.100
1.500
0.017
0.027
0.020
0.050
0.120
0.060
0.150
1.000
0.010
3.000
1.040

0.014
0.004
0.042
1.080
0.002
0.043
0.100
0.001
0.500
0.043
0.010
0.060
0.060
0.000
0.006
0.050
0.001
0.009
0.0003
0.120
4.500
0.005
2.000
0.625
0.060
0.400
0.100
0.205
3.000

0.020
0.0005
0.016
0.150
0.039
0.019
0.040
0.100
0.120
0.010
0.100
0.043
0.080
0.150
0.394
0.003
0.015
0.043






one of the leading states in the use and development of
desalting technology. Table 1 lists 88 desalting installa-
tions with a total capacity of 149 ML/d (39.6 mgd). Most
use reverse osmosis (RO) systems. Figure 1, a map of the
Florida peninsula, shows the general location of these
facilities, most of which are associated with coastal
communities.
Operational aspects
Consideration of desalting systems.for potable water
treatment commenced in the late 1960s, and, overall,
desalting systems have satisfactorily produced drinking
water that meets acceptable quality standards.
This new water treatment era began with the con-
struction of a flash distillation (FD) seawater conversion
unit in Key West, Fla. Although the design of the system
included using metals that would be less susceptible to
corrosion, the unit was plagued with serious corrosion
problems. The only time the facility produced at design
capacity was during start-up operations. This water
treatment plant has been replaced with an 11-ML/d (3-
mgd) RO seawater unit, and even this unit will be placed
on standby status as soon as a water transmission line
from the mainland can be completed. Seawater conver-
sion is substantially more costly than treating the
brackish groundwater available along Florida's coastline,
and the Keys would be the only area where a seawater
desalting system would be considered.
Three of the earlier desalinization units were electro-
dialysis (ED) plants. This process uses an electrical field
and membrane technology to separate mineral constit-
uents in water. Experience has shown this type of
treatment is less than satisfactory. Operating personnel
have had difficulty in meeting the secondary drinking
water standards. In view of this, ED should be considered
only for treatment of the lower mineral content in
brackish waters. Improvements in the process have been
reported recently with reversal of polarity in the units,
but no new ED systems have been installed in Florida.
Reverse osmosis is a feasible treatment process, with
many improvements having been made during the past
10 years. In original design concepts, pressures as high
as 6895 kPa (1000 psi) were considered. The first
installation in Florida was a 4137-kPa (600-psi) unit.
Now, low-mineral-content waters are being treated in
1379-kPa (200-psi) systems. Much has been learned
about designing the porosity of membranes for a specific
raw water. In some areas, RO-processed water is blended
with lime-softened water to meet the secondary stan-
dards. Other utilities use RO-processed water to blend
with raw water and, also, zeolite-softened waters. Such
blending permits utilities to cut operating costs and, at
the same time, to comply with drinking water regulations.
Reverse osmosis treatment units are compact, and a
system can easily be expanded with the addition of
another module. Because of the modular units, construc-
tion time is reduced considerably compared with con-
ventional treatment methods. In view of the ease of
operation and lack of ancillary problems, such as sludge
handling, several low-pressure membrane systems have
been used as interim facilities prior to integration with
larger municipal systems.
Bacteriologic fouling of membranes has been con-
sidered a possible problem in RO units, although there


Figure 1. Location of desalting plants in Florida



have been few reported incidences in Florida. In several
instances, membrane plugging was caused by turbidity
related to well-field development and well construction.
Development of brackish water as a potable supply
source has resulted in evaluation of liners and alternate
well casing materials. This fouling, related to finely
divided limestone and iron particulates in the water
source, has been greatly reduced by improved standards
for well construction.
Summary
Research is continuing on the use of RO and ultrafiltra-
tion, and these systems are being considered for treat-
ment of waste, removal of organic, and other similar
needs for separation of chemical constituents. Reports of
contamination of the nation's water supply resources are
reviewed and evaluated at an alarming rate. Desaliniza-
tion technology allows new handling of treatment pro-
cesses to meet these organic threats as well as to lower
normal mineral content. As water demand continues to
grow, it appears that RO systems will permit the
development of coastal water resources, and Florida will
continue to be one of the leading users of this technology
to fulfill the potable water goals of growing communities.

Glenn M. Dykes is administrator of the drinking water section of the
Florida Department of Environmental Regulation, Twin Towers Office
Building, 2600 Blair Stone Road, Tallahassee, FL 32301.


MARCH 1983


St. John


* Location of dealing plants


L


G.M. DYKES 107




University of Florida Home Page
© 2004 - 2010 University of Florida George A. Smathers Libraries.
All rights reserved.

Acceptable Use, Copyright, and Disclaimer Statement
Last updated October 10, 2010 - - mvs