CARIBBEAN RESEARCH INSTITUTE
WATER POLLUTION REPORT No. 13
DECENTRALIZED WATER REUSE SYSTEMS IN A WATER
SCARCE ENVIRONMENT: THE TOURIST INDUSTRY IN
ST. THOMAS, VIRGIN ISLANDS
Roger B. Kasperson
With the Assistance of Charles Schepart,
John Sorensen, and Robert Simpson
GOVERNMENT OF THE VIRGIN ISLANDS
DEPARTMENT OF HEALTH, DIVISION OF ENVIRONMENTAL HEALTH
WATER POLLUTION REPORT NO. 13
CARIBBEAN RESEARCH INSTITUTE
COLLEGE OF THE VIRGIN ISLANDS
DECENTRALIZED WATER REUSE SYSTEMS IN A WATER SCARCE
ENVIRONMENT: THE TOURIST INDUSTRY IN
ST. THOMAS, VIRGIN ISLANDS
Roger E. Kasperson
With the Assistance of Charles Schepart, John Sorensen, and
This report is based on the work of three undergraduate students from
Clark University, Worchester, Massachusetts, who operated under the partial
aegis of an agreement between the Caribbean Research Institute of the College
of the Virgin Islands and the Department of Health, Division of Environmental
Health, of the Government of the U. S. Virgin Islands. Partial funding was
also contributed by the Graduate School of Geography of Clark University and
the U. S. Office of Water Resources Research. The support from these
various sources is gratefully acknowledged.
This report continues a relationship between Clark University and the
U. S. Virgin Islands directed at research on environmental problems.
Previous studies have been conducted by Martyn J. Bowden, Associate Professor
of Geography, and John T. Reynolds, Professor of Microbiology, both of Clark
University. The present project is a continuation of an effort begun in 1970
dealing with water reclamation prospects in St. Thomas and carried over during
the independent study period at Clark University in January of 1971. The speci-
fic intent of the various projects is to collect and analyze a variety of informa-
tion concerning environmental problems which can be of direct use in planning
programs in the Virgin Islands. It also, of course, is an important application
of concepts and skills developed in pedagogy to the real world.
The present project was directed and coordinated by Roger E. Kasperson,
Associate Professor of Government and Geography at Clark University. Its
objective was to gather basic data on water consumption and sewage disposal
facilities at major tourist establishments in St. Thomas. These data were
analyzed with the specific intent of providing some rudimentary indications of
the feasibility of water reuse systems outside the limits of Charlotte Amalie.
The author wishes to express his gratitude to John Reynolds and Dan
Dworkin for reviewing the manuscript and suggesting a number of useful changes,
as well as acknowledge the helpful critical comments of Pedrito Francois,
Director of Environmental Health, and Neva Carlson, Research Assistant, at
the Caribbean Research Institute. The study is also indebted to Robert vanEepoel,
Research Associate and Project Director of the Caribbean Research Institute, who
encouraged us to do the research and provided assistance in the field work.
I. Introduction 1
II. A Definition of Terms 3
III. The Water Supply Situation in St. Thomas 4
IV. The Sewage Disposal Situation 8
V. The Growth of Tourism and Its Pact upon
Water Consumption 10
VI. Package Treatment Plants and Water Reuse 12
VII. Conclusions 14
VIII. Appendix 15
There has been much recent discussion concerning the need for techno-
logies to enlarge the range of choice in w ater supply for areas suffering from
either limited surface and ground water supplies and/or burgeoning domestic,
industrial or commercial demand. In most insular and maritime environments
the search for enlarged supply generally involves consideration of desalinization
Such has been the case in St. Thomas in the U. S. Virgin Islands where three sea-
water desalinization plants have been constructed during the last decade to meet
the municipal needs of the Charlotte Amalie system. These plants are all of the
flash-distillation type and have capacities of .275, 1.0 and 2.5 mgd respectively.
Since many outlying areas in the island also draw upon the municipal system to
augment their own supply, in effect desalinization is serving many of the .large
volume users on the island. Thus far, this means of augmentation has met the
rapid population and touristic growth in the city of Charlotte Amalie; it is a much
less satisfactory supply solution, however, for the rest of the island.
The search for means to augment water supply has included some attention
to alternative systems. Charlotte Amalie has long employed a dual water system
in which salt water has been used for flushing and waste disposal. In 1968,
Engineering-Science, Inc. completed a water reclamation study for the Virgin Islands
which included proposals for reclamation and reuse on both St. Thomas and
St. Croix. Hotels and resorts have, either on a permanent basis or during
droughts only, urged their guests to restrict their consumption of water. Some
have even tried to add incentives to compliance by suggesting "Shower with a Friend."
Some employ water-saving devices, such as automatic shut-off showers and faucets,
other systematically monitor their system for leakages.
There has apparently been little systematic study, however, of the growth of
high volume users in the tourist industry scattered throughout the island in areas
remote from the production of desalinized water. The rapid appearance of this
network of commercial establishments in an island with limited and uncertain water
resources and a high quality physical environment directly connected to its economic
well-being raises difficult problems both for efficient water supply and waste disposal.
In such a situation, there is a unique opportunity for a decentralized water reuse
system which employs package treatment plants and utilizes the effluent to reduce
the high costs of water supply. Simultaneously, the reduction of wastes disposed
directly to adjoining maritime waters helps preserve the aesthetic properties of a
beautiful physical environment.
This study has as its objective, therefore, to survey the means by which tourist
establishments are presently dealing with their twin problems of water supply and
sewage disposal and to assess in a very preliminary way the feasibility of water
reclamation and reuse systems. The scope of the study is limited, therefore, to
private touristic establishments and does not include experimentation by residential
subdivisions, other residential estates, or industrial firms. To gather data, a
stratified sample of sites was selected so as to include the largest tourist establish-
ments as well as a number of smaller resorts. A number of establishments
within the Charlotte Amalie system were interviewed as control observations with
which to compare our sites outside that system. Several sample establishments
refused to cooperate; a number of others showed obvious disinterest. The final
eighteen establishments studied are shown on Map. 1. The records kept by each
vary widely, however, so that the evidence for the study is still fragmentary
and incomplete at best. The interview utilized is included as an appendix, and was
given to owners, managers, or maintenance engineers.
H. A DEFINITION OF TERMS
The literature on water reuse is plagued by a plethora of terms and meanings.
To clarify the present discussion, a number of preliminary definitions are proposed:
Package Treatment Plant a wastewater treatment plant ranging in
capacity from 600 gpd to 140, 000 gpd that utilizes long-term aeration,
final sedimentation and chlorination and which is designed to serve
resort complexes, shopping centers, apartment buildings, factories,
small subdivisions, and even private homes.
Reclaimed Water wastewater which has been treated with the
specific intent of restoring its quality to a level where it may be
utilized as a source for augmenting water supply.
Renovated Water wastewater which has been treated to a level
which restores its quality to that which prevailed prior to its use
in the supply system under consideration. As used here, then,
renovated water is a high quality subclass of reclaimed water.
Water Reuse the use of reclaimed water.
III. THE WATER SUPPLY SITUATION IN ST. THOMAS
The climate of the Virgin Islands is, of course, a key factor in the tourist
industry. Temperature averages 780F. and generally ranges between 70 and
90F. The mean rainfall is commonly set at 44. 63 inches, but a recent study by
Martyn Bowden has indicated that less than 42 inches is probably more accurate.
In addition, his study indicates a long-term drying trend in the Virgin Islands as
a whole. 3 There is much variability in seasonal and annual rainfall. Since
most of the rainfall is convectional in type and average slope of the island great,
the rate of runoff is also high. Droughts are common; Martyn Bowden indicates
that St. Thomas has experienced a drought every year since 1934 according to
the Palmer index.4 Ground water is limited and does not constitute a source of
significant supply except in some scattered interior areas. Since most tourist
establishments locate on the shoreland perimeter of the island, surface waters
are usually unavailable and whatever ground water is present tends to be brackish.
The traditional supply system on the island is a combination of rain barrels
in residential slums, rain cisterns for most residential areas including the
isolated single family dwellings scattered throughout the island, and catchments
for institutions and settlement concentrations. It was in 1926 that small areas
for rain catchment were first installed with a drain off into concrete storage tanks
to supplement the roof water flow into house cisterns. By 1945 there were 440, 000
square feet of paved catchment areas and a 3.5 million gallon storage capacity in
the Charlotte Amalie supply system. 5 Cisterns, catchments, and rain barrels all
reply upon rain water, however, so the island has since 1955 needed a supplemental
supply to handle periods of drought as well as the rapid population, touristic growth,
and per capital consumption increases in Charlotte Amalie over the last two decades.
Water barged from Puerto Rico has filled this gap in the municipal water supply
system and provided a buffer against rainfall uncertainty. The volume of barged
water has reached extensive proportions; in fiscal year 1968, for example, 180
million gallons were barged from Puerto Rico. In recent years, however, the
construction of the desalinization plants in Charlotte Amalie has replaced barged
water as the major source for the municipal supply. The regular contract for
water barging has now been terminated.
The development of the municipal supply has not, however, solved the problem
for outlying establishments in St. Thomas. They have been forced to deal with the
question of water supply individually, and a variety of adjustments has resulted.
As Table 1 indicates, all of the establishments outside of the municipal system and
all but one (Carib Beach) inside the system utilize cisterns for at least a portion
of their supply. Not only does the cistern collect available rainwater, but the
related impoundment facility also provides storage needed whatever the source of
supply. Ground water is rarely a significant means of supply and where it is
employed the well water is generally used primarily for flushing purposes.
Cisterns are relatively economical both to install and to maintain. The Virgin
Islands Hilton indicated that their three cisterns of 50, 000 gallons capacity cost
approximately $15, 000 each to install. Assuming a 20-year project life, an
eight per cent discount rate, and an annual maintenance and operation expendi-
ture of $700, this works out to about 5.3 cents per gallon per year for construct-
ing and operating the cistern. Of course, that facility furnishes in any given
year many gallons of water for each gallon of capacity depending upon the extent
of rainfall and the total area of roof catchment.
Given the relative cheapness of installation, the low maintenance and
operating costs, and the high quality of the product delivered, the extensive use of
cisterns as the common denominator for water supply is an effective managerial
adjustment. The scale of investment in cisterns is limited largely by the roof
space available and influenced obviously by access to the municipal system. All
the larger resort complexes Pineapple Beach Club, Sapphire Bay Resort,
Limetree Hotel and Beach Club, and Cowpet Bay Village In our sample located
at some distance from Charlotte Amalie have installed cistern capacities ranging
from 750, 000 to 1,205, 000 gallons. Table 2 shows the overall pattern of cistern
development at tourist establishments.
Cisterns are not in themselves, because of the variability of rainfall, adequate
to ensure a dependable supply, however. As a result, individual enterpreneurs
have looked to several means for augmenting supply; the purchase of water from
trucking companies, desalinizing water from the sea, or utilizing either sea water
or reclaimed waste water in a dual supply system. Restricting consumption is also
a possibility, but most establishments have chosen to eschew this alternative.
Trucking companies for water have operated in St. Thomas since about 1954.
The oldest of these, Trans-Inc. Water Company, owns three trucks, each of which
can carry up to 10 tons (2500 gallons of water), and serves approximately 150
regular customers during dry years. The water companies obtain water from
the municipal system at the standard price of $2.o0 per 1,000 gallons. All
charge the consumer a standard price determined by his location in the rate
structure of the island (Map 2). Large volume consumers may be given a slightly
reduced rate, especially if they obtain a regular contract with the trucker. The
cost of water jumps astronomically as one leavesthe city limits; one hundred
thousand gallons of water obtained from a municipal connection costs the buyer $200,
whereas a consumer immediately outside the city limits must pay $1,400 for the same
amount from a trucker. A buyer on the western end of the island, perhaps 45
minutes to an hour away from the city, must pay $2,000 for those same 40
truckloads of water.
The implication for large volume water-using establishments is clear;
water becomes a very significant operating cost. Water purchases at the
Indies House, a moderate size establishment of 32 units, run $1,900 a month
during 100 per cent occupancy, even with cisterns and extensive reuse. The
respondent at the Lime Tree termed water the highest operating expense for
the establishment in the first three months of its operation. At the large
Sapphire Bay Resort (580 guest capacity), the 1970 bill for water purchases
was $60, 000, and that with only about a 50 per cent occupancy rate for the year,
with a salt water flushing system, and a water purchase rate reduced to $9.00
per 1, 000 gallons.
The high cost of water in the non-municipal areas of the island is not,
however, due to extravagant profits by the trucking companies. Rather, it
arises from a system containing a single point of supply with very high transfer
costs involved in distribution. Roads are generally poor and crowded along the
precipitious slopes of St. Thomas, and the cost of acquiring the trucks, parts,
and maintenance skills to keep a water trucking operation going in a Caribbean
island is outrageously expensive. Anticipating substantial savings in the cost
of water, the Pineapple Beach Club acquired its own water truck and bought
directly from the municipal system at $2, 00 per 1, 000 gallons. Managers of
the club estimate that they were able to reduce their total cost of water to
$7. 00 per 1, 000 gallons, but this figure includes water from all sources and they
may be under-estimating depreciation costs. Such an option is not, in any case,
a viable alternative for smaller establishments.
The second major adjustment employed to deal with the supply problem is
to reduce the volume of high cost water which must be purchased. One method
is to restrict the volume of water consumed by guests. Since the consumption
of guests was estimated in our interviews as ranging between 125 and 200 gpd
compared with a mainland figure of about 70 gpd (excluding industrial use), there
would appear to be ample opportunity for cutting costs. Yet, none of the 18
establishments interviewed presently imposed any water restrictions upon guests,
despite the fact that 1970-71 was a dry year. The extent of action in this
direction is to post signs politely asking guests to conserve water (and the Virgin
Islands Hilton and Michele Motel have removed even this request), to install
automatic shut-off showers and faucets, and to monitor and fix dripping faucets.
The explanation for the lack of adjustments to reduce guest consumption is that
tourists would not wish to pay the high price (ranging up to $70 per capital per day)
for accommodations in the Virgin Islands and be told to restrict water.
A second means of reducing the cost of high quality water is to install a
dual water supply system which will utilize a poorer quality water for such
lower order uses as flushing and lawn irrigation. This is by no means a
recent innovation in St. Thomas for the city of Charlotte Amalie has long had
a separate salt water system for exactly this purpose. Since salt water costs
only 15 per ton (with a small charge for the connection) as compared with
50 for potable water, many inhabitants and merchants in the city have taken
advantage of the savings possible. Drawing upon this precedent, resort
complexes outside the municipal limits have also installed dual systems. Such
systems have frequently been based upon salt water where the complex is
adjacent to the sea. Generally salt water is pumped from the sea, used for
flushing, treated, and returned to the ocean. In others, the fresh water
effluent is treated and circulated through the secondary system for flushing and
irrigation. There is still a third system which draws upon brackish water
from wells for the lower quality water. The distribution of these dual systems
is shown on Map 3.
IV. THE SEWAGE DISPOSAL SITUATION
Although not as severe as the water supply problem, sewage dis-
posal also creates problems for local inhabitants and merchants. Even
in Charlotte Amalie, the only municipal scale sewage disposal system on
the island, raw sewage is inadequately collected and dumped into the adjacent
harbor. The present facilities handle an average of 2 1/2 mgd and are
badly overburdened. Approximately 70 per cent of dwellings now are
connected to the municipal sewage system. A developmental plan is in the
initial stages, however, for a primary treatment plant, interceptors, force
mains, and pumping stations. Bids have already been taken on the treatment
plant and interceptor and the municipal disposal situation should be improved
over the next three to four years. There are no immediate plans for switching
from the dual system to a completely fresh water system, because of the
dramatic increase in water supply that would be required.
Outside of Charlotte Amalie, there are, according to a study conducted
by John Reynolds, some 53 treatment plants in use. 6 Tutu presently has two
package treatment plants, of which one operates at low efficiency and effect-
iveness. Ultimately there is thought of a central sewage system and treatment
plant in Tutu, but there are no plans for the immediate future. The study
by Engineering Science, Inc. suggested that Tutu could process its sewage for
ground water recharge since it is one of the few areas where such a system
would be possible.
Tourist establishments outside Charlotte Amalie use both septic tanks
and package treatment plants in sewage disposal. Reynolds estimates that there
are at least 1250 septic tanks in use at various facilities in the rest of the
island. 8 He also notes that terrain and soil characteristics create problems
in installation and maintenance. The five tourist establishments surveyed in
this study which use septic tanks confirm this generalization. Normal
maintenance charges ran between $600 and $900 per year at the five sites, but
did not include periodic major expenses.
Pelican Beach Club furnished the most complete data on septic tank costs.
For its capacity of 44 guests, it built 14 septic tanks in 1961 at costs ranging
from $1200 to $1400 for each tank. Its annual maintenance charge for the complex
is $900. Assuming a 20-year project life and an eight per cent discount rate,
this works out to be about $78 per guest per year for sewage disposal, assuming
100 per cent occupancy. Yet this figure seriously underestimates cost, for
the management has experienced considerable problems with its septic tanks.
Six years after installation, it had to dig up all the lawns and replace all the
drainage pipes and fields. Sapphire Bay abandoned their septic tank system
and moved to large-scale package treatment after experiencing problems with
their system. Although figures were not available on the costs to the Pelican
Beach Club, they must have been very substantial. Over the experience of
the past 10 years, then, an adjusted figures of about $95 per guest per year
for sewage disposal, assuming 100 per cent occupancy, would appear to be more
realistic for this establishment.
The situation for package treatment plants will be analyzed in the discussion
of water reuse systems. First, it is necessary to summarize briefly the recent
growth of tourism in St. Thomas and to analyze its impact upon water consumption.
V. THE GROWTH OF TOURISM AND ITS IMPACT UPON WATER CONSUMPTION
Tourism is presently the most important single industry in the Virgin
Islands. Attracted by the climate, beaches, the largely unpolluted environment,
and the $200 gift and one gallon of liquor duty-free allotment for visitors
returning to the mainland and Puerto Rico, tourists visit St. Thomas in large
numbers and spend sizeable sums shopping. The government of the Virgin Islands
estimates that receipts from tourism have grown from $25.3 million in 1960 to
$112.3 in 1969, a more than fourfold increase. Motor vehicle ownership has
Increased from 5, 000 in 1960 to 18, 000 in 1968. Over the same period, per
capital income has risen from $950 to $2200 per year. Since Pan American
inaugurated flights to the islands in January, 1966 (followed by Trans Caribbean
and Eastern in 1969), air traffic has grown from 339, 665 passengers in 1966 to
566,586 in 1969. Preliminary figures for 1970 show some setback, however,
reflecting the general economic decline and the lowering of North Atlantic air fares.
There is also a marked seasonality to tourism in the Virgin Islands (Figure 1); in
fact, several establishments close up entirely during the summer off-season.
Because of this growth of tourism (Table 3), the number of hotels and resorts
in St. Thomas has increased markedly. In 1960, there were 36 hotels with a total
of 841 rooms on the island. A decade later, these figures had increased to 64 and
1, 924 respectively, for an average annual growth rate of 12. 9 per cent. Although
this rate is lower than the average annual increase of 18. 6 per cent in air arrivals,
it is only recently that St. Thomas has attracted overnight visitors on a large scale.
The chronological development of tourist resorts included in this study is shown
in Map 5. The Virgin Islands Tax Incentive Act which exempts qualifying hotels
from real estate taxes for a 16 year period also encourages hotel building.
Table 4 provides a summary of the present size and projected growth of the
tourist establishments included in this study. Particularly striking are the largest
resort complexes, built in the last decade in outlying areas of the island, generally
with adjacent beaches. Pineapple Beach Club, Sapphire Bay Resort, and Cowpet
Bay Village all are examples. A number of these, as indicated in Table 4, are
planning major expansion in the near future. Given the limitations outlined above
in the water supply and sewage disposal situations, resort development has already
had an impact upon investment and operating costs.
In the Virgin Islands, water consumption is thought to have increased from
87 million gallons in 1960 to 555 million gallons in 1968. Precise estimates of
water consumption are extremely difficult to obtain, however, for records are
not kept of water obtained from rain cisterns. The only accurate figures for
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outlying resorts, except for Pineapple Beach which has overall cost estimates, relate
to purchases from either the municipal system or the water trucking companies.
Wherever possible, respondents were asked to refer directly to their records of bills,
so that the estimates shown in Table 5 can be assumed to be reasonably accurate for
that portion of the water supply. Figure 2 indicates the extent of seasonality of
consumption, and Map 6 shows the geographical pattern for water consumed at these
sites. The major consumers in Charlotte Amalie are the Virgin Islands Hilton and
Yacht Haven. The large consumption at the latter arises from the heavy use of
fresh water for washing and servicing the marina. Outside Charlotte Amalie, the
concentration of water consumption at the eastern end of the island is readily apparent.
The projected future growth at Sapphire Bay and Belongo Bay Beach Club, apart
from other resort complexes which may be expected to locate in the general area,
indicates major water supply and sewage disposal needs on this end of the island during
the next decade.
Some rough estimates of water cost may be useful in the ensuing discussion of
water reuse. Using an efficient supply system of its own water truck, 48 rain
cisterns, and a salt water flushing system, the management of the Pineapple Beach
Club estimates their cost for water over the project life of the facilities at 7/0l per
gallon ($7. 00 per 1, 000 gallons). With the guest consuming an estimated average of
200 gallons per day, this works out to a per guest per day cost of $1.40 and a per
guest per year cost of $511. Yet this figure includes substantial reduction in cost
because of the use of a salt water flushing system. A figure if water costs based on
an entirely fresh water system would be closer to $1. 85 per guest per day or 9/10
At the new Lime Tree resort complex, water is obtained from 11 cisterns of
80, 000 gallons capacity each, the balance of fresh water from water trucking companies,
and treated effluent is used for irrigation and cleaning. With a $6, 000 water bill
monthly at full occupancy and $16 for every 7 tons, per capital per day water con-
sumption is approximately 122 gallons (excluding that from cisterns and treated
effluent) at a cost of $1.12. Again, with an entirely fresh water system, assuming
cisterns but no treated effluent, the costs would probably be about $1.40 per guest
per day or about 1. 2 per gallon. If the role of cisterns is assumed equal, this is
probably quite close to the figures for Pineapple Beach Club.
With this background of present and projected water consumption and sewage
disposal needs and some very rudimentary cost guidelines, let us now consider
the development of decentralized water reuse systems in St. Thomas.
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VI. PACKAGE TREATMENT PLANTS AND WATER REUSE
Package wastewater treatment plants have been in use for perhaps the last
10 to 15 years in areas of mainland United States. They are pre-engineered units
with capacities ranging from 600 to 140,000 gpd and designed to serve shopping
centers, resort complexes, apartment buildings, etc. 10 These plants remove
80 to 85 percent of the BOD (Biochemical Oxygen Demand) and suspended solids
when properly operated and maintained. The survey by Reynolds of the performance
of package treatment plants in St. Thomas indicates that even better effectiveness
may be realized. He found some 53 treatment plants in use, of which 23 involved
some direct reuse of chlorinated effluent. 11
Our survey of tourist establishments indicates a trend away from septic tanks
and toward package treatment plants. During the 1950's two of three resort complexes
built installed septic tank systems; during the 1960's five of eight tourist establish-
ments built installed package treatment plants. This change stems largely from
legislation governing the design of sewage disposal systems passed under the Water
Pollution Control Act of 1967. Since that act, the Health Department has required
package treatment plants for sewage generated in excess of 2, 000 gallons per day.
Thus, all four complexes built since 1967 have utilized such facilities. The
analysis to follow will demonstrate the wisdom of this action. Map 7 shows the
geographical pattern of this growth of package treatment systems.
The six package treatment plants in the 18 sites studied are of two major types.
The first, such as that employed at the Indies House and Cowpet Bay Village, is a
fresh water system which reuses the effluent for flushing and irrigation. The
second, such as that at Pineapple Beach and Secret Harbour, treats a mixed fresh
and salt water (and in the case of Pineapple Beach brackish water) which is then
returned to an adjacent maritime body. Both systems clearly result in sub-
stantial savings so that ready access to salt water or alternative sources may be
the determining factor. There also is the initial benefit, not included here, of
pollution abatement in adjacent maritime bodies. Indies House, for example, is at
an inland location so that the reclamation of fresh water rather than a dual fresh and
salt water system is the obvious choice. Cowpet Bay Village has access to an
inexpensive fresh water well so that a fresh water reclamation system is probably
more feasible. In any event, water is sold directly to the guests at this resort
complex. Table 6 shows summary statistics for the six plants.
A detailed examination of several establishments provides some rough
estimates of the cost of water treatment plants for sewage disposal. Assuming a
20-year project lift, an eight per cent discount rate and 100 per cent occupancy, the
cost of sewage treatment at Lime Tree works out to $105 per guest per year. But
these figures are for the first three months of the resort's operation; it is likely
that these costs will come down. A similar calculation for Cowpet Bay Village
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reveals a figure of $66 per guest per year. For Indies House, the figure is $69.
These figures are not substantially different from the figure of $78 (or $95) for
the cost of sewage disposal by septic tanks at the Pelican Beach Club. It should
be noted that the Pelican Beach Club may not be representative of costs at other
sites. Yet there is little evidence in our study of the rough rule of thumb cited
by several respondents that septic tank systems cost only 50 per cent of that for
package treatment plants.
But the latter has the added advantage of permitting reuse of the effluent,
thereby reducing costs. Using figures derived from the tourist complexes
studied, a hypothetical example may be used to analyze the economic feasibility
of package treatment and reuse systems. Let us assume a new 50 unit resort
complex with a 100 guest capacity located on the eastern end of St. Thomas. Let
us further assume a cistern capacity of 200, 000 gallons, the ability to buy water
from trucking companies at $10 per 1, 000 gallons, and a per capital consumption
of 200 gallons per capital per day, of which cisterns will furnish 75 gallons per day.
At 100 per cent occupancy, the management could expect an annual water bill of
$45, 625; at 75 per cent occupancy, the bill would be $27,375.
Given such a resort complex, what would be the net advantages or disadvantages
of installing a septic tank disposal system versus a package treatment plant and
reuse system? Let us assume that sewage disposal by a package treatment plant
costs $80 per guest per year (the mean figure for the 3 package treatment plants
cited above.) This would be an annual fee of $8, 000 for the establishment under
question assuming full occupancy. Let us further assume, to be on the conser-
vative side, that a septic tank system could be installed at a half this cost, or
$4, 000 per year. It should be noted that such a cost differential is unlikely based
upon our study results.
The package treatment plant would permit reuse of its effluent for flushing and
lawn and garden irrigation. Managers continually estimated flushing and irrigation
at 50 per cent or more of total consumption. This figure corresponds with estimates
gathered in less arid areas of the United States where water savings fixtures are not
employed. Even a one-third reduction in water consumption would, at full occupancy,
result in savings of $23, 725. After the $4, 000 additional cost in the sewage disposal
system is considered, a net savings of $19,725 has still been realized. From this
must be deducted the additional capital investment required for the dual water supply
system (piping and storage) but there can be little doubt that the reuse system can
substantially cut costs where water supply is unusually expensive. Table 7 provides
a summary analysis of the economic competitiveness of reuse at varying occupancy
levels. The recent actions and future plans by resort complexes indicate that they
too share this belief.
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This study is obviously a preliminary effort to gather data relating to
the water supply and waste disposal problems involved in the growth of a tourist
industry in St. Thomas. The results indicate the key role played by water
supply in the investment and operating costs of resort complexes, particularly
those in areas distant from Charlotte Amalie. The data gathered in our
interviews indicate that substantial economic savings are possible through
water reclamation. There will, of course, be further growth in the use of
such decentralized water reuse systems in the Virgin Islands, but the economic
analysis contained in this report indicates the potential for package treatment
and reuse systems elsewhere in the Caribbean.
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1 Tourist Establishments included in the Study Sample
2 Rate Zones for Trucked Water (per 1,000 gallons)
3 Tourist Establishments with Dual Water System
4 Type of Sewage Disposal System used in Tourist Establishments
5 Date when Tourist Establishment Built
6 Volume of Water Purchased at Selected Tourist Establishments
7 Package Treatment Plants at Tourist Establishments (by year built and
capacity in thousand gallons per day)
1 A Seasonal Profile of Tourist Occupancy at Selected Resort Establishments
2 Cumulative Water Purchases for Selected Establishments (1970)
1 Source of Water Supply for Selected Tourist Establishments (1971)
2 The Distribution of Cisterns Among Tourist Establishments
3 Visitors to the U. S. Virgin Islands by Method of Arrival
4 Present Guest Capacity and Projected Growth for Selected Tourist Establishments
5 Managerial Fstimates of Water Purchases, 1970
6 Summary Statistics for Package Treatment Plants at Selected Sites
7 Net Costs and Savings of a Water Reuse System at an Hypothetical Tourist
Resort with a 100-Guest Capacity
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SOURCE OF WATER SUPPLY FOR SELECTED TOURIST ESTABLISHMENTS (1971)'
SITE MUNICIPAL 1 CISTERN WELLS TRUCK OTHER
Lime Tree Hotel
& Beach Club X
Mafolie Hotel X
Secret Harbor X
Miller Manor X X
Tropic Isle X na
Beach Club X
Salt water for flushing
Salt water for flushing
Salt water for flushing
Reused water for flush-
ing & gardening
Well water from Tutu
& effluent for flushing
Effluent for flushing
Salt water for flushing
Treated salt water
Salt water for flushing
Salt water for flushing
Water trucking for emergency only.
Regular contract with water trucking company
Bluebeard's Castle sends water to Beach Club by
Pineapple Beach Club owns its own truck.
Data not available
its own truck.
THE DISTRIBUTION OF CISTERNS AMONG TOURIST ESTABLISHMENTS
SITE NUMBER OF CISTERNS TOTAL CAPACITY FUNCTION
Virgin Isle Hilton
Cowpet Bay Village
Lime Tree Hotel and
Pineapple Beach Club
Pelican Beach Club
Pavillions & Pools
Bolongo Bay Beach
guest use pool
watering of land-
VISITORS TO THE U.S. VIRGIN ISLANDS BY METHOD OF ARRIVAL
METHOD OF ARRIVAL 1964-65 1965-66 1966-67 1967-68 1968-69 1969-70
BY AIR 354,371 436,775 516,295 651,098 908,776 n.a.
BY SEA* 84,653 100,00 95,066 105,810 156,975 n.a.
BY CRUTSe SHIP 109,341 117.659 133,35' 166,117 213,541 251,084
TOTALS: 548,365 654,434 744,718 923,025 1,279,292 n.a.
NUMBER OF MOTEL
BEDS 3,911 4,345 5,615 6,223 7,004 n.a.
*NOTE: These sea arrivals are for Armed Services, private yachts, and
n.a.: Data not available
SOURCE: Virgin Islands Department of Commerce, Visitors Bureau
PRESENT GUEST CAPACITY AND PROJECTED GROWTH FOR SELECTED TOURIST
SITE Number of Rooms Projected Unit Percentage
or Units Growth for Growth
I Next 10 Years____
Virgin Isle Hilton
Cowpet Bay Village
Lime Tree Hotel
Pelican Beach Club
Sapphire Bay Resort
Pavillions & Pools
Bolongo Bay Beach Clut
60 and hotel
65 rooms and
I I I-
n.a.: Data not available
MANAGERIAL ESTIMATES OF WATER PURCHASES, 1970
Virgin Isle Hilton
Cowpet Bay Village
Lime Tree Hotel
Pelican Beach Club
Pavillions & Pools
Water Purchases (in
Thousands of Gallons)
L ___ __ I 'I
Total Cost of
a. 11 month total
b. Initial fee of $2.00 plus transportation costs. Bluebeard's Castle ships water
to Bluebeard's Beach Club in:its own water truck.
c. Figures included total volume of water consumed, rate of cost is for the truck
owned by the establishment, and the total cost of water supplied by all sources.
d. 10 month total
e. of which 300,000 is from water trucks and 1,000,000 from well in Tutu
f. includes only water from trucking companies
SUMMARY STATISTICS FOR PACKAGE TREATMENT PLANTS AT SELECTED SITES
Date g.p.d. Installa- Annual
Treatment Capacity tion Operating 'Use of Projected
Site Type Installed Treatment Cost Cost Effluent Expansion
Indies House Conglomerate 1968 8,500 $20,000 $1,800 flushing, another
System: irrigation holding
Fresh Water tank
Cowpet Bay Chicago Pump 1967 25,000 $35,000 $9,000 flushing, new plant-
Village Fresh Water irrigation 80,000 gpd
Lime Tree Dafco2
Aeration and 1969 47,000 $45,000 $12,000 flushing, none
Lift station irrigation
Pineapple Dafco; mixed 1969 45,000 $80,000 $10,000+ piped to tertiary
Beach salt and bay treatment;
brackish $25,000 of
well water electric
to be in-
Secret harbour Dafcoi salt 1968 25,000 N.A. $1,000 piped to sea none
Sapphire Bay Chicago Pump; 1969 50,000 N.A. $18,000 piped to tertiary
Salt Water lagoon treatment
NET COSTS AND SAVINGS OF A WATER REUSE SYSTEM AT AN HYPOTHETICAL
TOURIST RESORT WITH A 100-GUEST CAPACITY
25% 50% 75% 100%
Total Daily Water Requiredl 5,000 10,000 15,000 20,000
Water From Cisterns 7,500 7,500 7,500 7,500
Water Purchases (@$10.00 per
1,000 Gallons) 2,500 7,500 12,500
Annual Cost of Water2 9,125 27,375 45,625
Water Provided through Reuse
(1/3 of total Consumption)3 3,500 5,000 6,500
Daily Water Purchases
with Reuse System 2,500 6,000
Annual Cost of Water
with Reuse System 9,125 21,900
Annual Savings on Water Cost
with Reuse System 9,125 18,250 23,725
Extra Cost of Package Treat-
ment Plant4 3,400 3,600 3,800 4,000
Net Annual Cost of Reuse
System 3,400 -
Net Annual Savings of Reuse
System 5,525 14,450 19,725
1. Assuming an average per capital consumption of 200 gallons per day. including
irrigation, swimming pool, and maintenance uses.
2. Excluding cistern costs which are here assumed c constant with alternative
systems. The assumed cistern capacity is 200,000 gallons.
3. Figures rounded.
4. Over the cost of a sewage disposal system using septic tanks. Calculations
assume that package treatment costs include an initial $3,200 fixed cost
and an operational expense of $200 per 25% capacity at the given scale.
MAP 1 IN
Haven Pavillions and Pools
R.:,-., i~ 'o o g a .: ':-:'::':' '-,.... ..
S= Sea Water
B= Brackish Water from Wells
Municipal System (Charlotte Amalie)
S= Septic Tanks
T= Treatment... Plant.......... ::
T= Treatment Plant
.6 .0 19........ .....
: .. .
FATER PURCHASED AT SELE
fS AT TOt
I-wu -[.% 1-16
A SEASONAL PROFILE OF TOURIST OCCUPANCY AT SELECTED RESORT ESTABLISHMENTS
I/ %.. 4.
U 5,1 at
- I V 9 -
Indies House December-March 85%
CUMULATIVE WATER PURCHASES FOR SELECTED ESTABLISHMENTS
400 / ..oO.** ,*; '
JAN FEB MAR APR MAY JUNE JULY AUG SEPT OCT NOV DEC