I I I
The Robert A, Toft
Sanitary Engineering Center
TECHNICAL REPORT
W59-2
lllllll
REMOVAL OF RADIOLOGICAL,
BIOLOGICAL, AND CHEMICAL
CONTAMINANTS FROM WATER
U.S. DEPARTMENT OF HEALTH,
EDUCATION, AND WELFARE
Public Health Service
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SEC TR W09-2
REMOVAL OF RADIOLOGICAL, BIOLOGICAL,
AND CHEMICAL CONTAMINANTS FROM WATER
This report is a reprint of a final report to the
Department of the Navy, Bureau of Yards and Docks,
prepared under Project NY 300 010, Sub-project 6,
entitled "Development of Practical Methods for
Removal of Radiological, Biological, and Chemical
Contaminants from Water Supplies". It is released
with the approval of the Department of theiNavy.
Richard L. Woodward and Gordon G. Robeck,
Water Supply and Water Pollution Research
DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE
Public Health Service
Bureau of State Services
Division of Sanitary Engineering Services
Robert A. Taft Sanitary Engineering Center
Cincinnati, Ohio
1959
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PREFACE
The investigations described in this report were
designed to meet specific requirements of the Navy,
and the findings may not be directly applicable to
civilian water systems. It is being issued as a
report of the Robert A„ Taft Sanitary Engineering
Center because of numerous requests for copies
which could not be met with the small number pre-
pared initially.
ii
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CONTENTS
Abstract v
Introduction 1
Radiological 2
Hazard .' 2
Design Criteria 6
Type,Size, and Cost of Units 7
Biological 10
Hazard 10
Design Criteria 16
Chemical 25
Hazard 25
Design Criteria t. 28
Summary • 29
Appendix A
Fallout Studies 31
Appendix B
The Effect of Free Available Chlorine and Chlorine
Dioxide upon Shellfish Poison (Aqueous) at pH 7.0
and 25 °C U2
Appendix C
I. Dechlorination with Granular Activated Carbon
Beds U5
II. Removal of Clostridium botulinum Type A Toxin
from Water by Passage Through Activated Carbon.U8
III. Use of Carbon for Removal of GB from Water ... 52
Appendix D
Design of Gravel Filled Chlorine Contact Tank .... 60
ill
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Appendix E
Estimated Costs for Re-treating Water to Protect
Against Spores, Vegetative Bacteria or Toxin
Appendix F
Monitoring for BW and CW Agents in Water with
Fish 119
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ABSTRACT
Hazard evaluation studies have shown that shore based Naval water
supplies can be contaminated by chemical, biological, and radiological
warfare agents. The greatest hazards to be guarded against appear to be
radioactive fallout in surface waters amj CQvert .^^^ ^ ^
vegetative bacteria or botulinum toxin into a water distribution system.
Laboratory and engineering studies were conducted to determine the
design criteria and cost estates of providing and operating devices to
protect against these contaminants,,
Small disposable columns of mixed cation-anion exchange resins will
remove the soluble radionuclides enough to suffice for immediate drinking
and culinary purposes near the point of use, providing a 99 percent removal
will lower the radioactivity level to 0 .1 nc/kU
Chlorination sufficient to provide free available chlorine residuals
of at least 1 mg/liter after an assured contact period of 5 minutes will
destroy 99.9 to 99.99 percent of the most likely BW agents.
Chemical warfare agents are 'so numerous and varied that it would
not be feasible to provide a single protective device to cope with them.
In general, the standard chemical warfare agents are less suitable as
intentional water contaminants than some of the biological agents. Some
of the chemical agents now being developed may be more dangerous as water
contaminants than the standard agents.
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DEVELOPMENT OF PRACTICAL METHODS FDR REMOVAL OF RADIOLOGICAL,
BIOLOGICAL, AND CHEMICAL CONTAMINANTS FROM WATER SUPPLIES
INTRODUCTION
The purpose of this project has been to develop design criteria and
operating procedures for water treatment plants intended to remove or in-
activate radiological, biological, and chemical warfare agents that may be
encountered at continental Naval Bases in the United States0
Investigation has shown that one set of design criteria is not
feasible for general application, but that the purpose of the project can
be accomplished better by considering two typical plants as followss
10 A plant for typical continental Naval Base, using water
from an open reservoir or river, not normally contaminated
by excessive sewage or industrial wastes, capable of pro-
viding about 1,000,000 gal/day of potable water. The
plant is to operate normally in peace-time, but be capable
of handling the radiological, biological, or chemical
attacks on short notice in the event of contamination of
the raw- water0
20 A plant for removal of these special warfare contaminants
only, to be cut into a potable water system in event of actual
or expected attack,. This assumes contamination of water after
undergoing ordinary treatment. This type of plant would be
located near the point of consumption,, Approximate capacity
about 100,000 gal/dayc
- l -
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- 2 -
This report will not cover other situations such as using ground-
water, although it is understood that stored water from covered tanks,
bottles, or the ground would be the most effective protection against
these contaminants0
Even when the water supply conditions are as limited as the two
given above, it is apparent that no one treatment will suffice for all
three types of warfare agents at one time. Therefore, each type of agent
will be considered separately and any combination of devices can be dis-
cussed later.
RADIOLOGICAL
Before presenting the design criteria that have been developed, it
is advisable to review some of the findings of the hazard evaluation studies
made in connection with this project, and the information available on
detection and present treatment of warfare agents since such considerations
play an important role in determining design of protective measures0
HAZARD
Short-Term Basis
The principal hazard to be guarded against is contamination of
surface waters by primary fallout from high yield nuclear weapons. Jrom
the information available, it has not been possible to evaluate all of the
pertinent factors affecting the hazard likely to be encountered. However,
it is apparent that water contamination is not likely to significantly
reduce the military effectiveness of personnel using it, except where the
general level of contamination is extremely heavy (greater than 1,000 r/hour
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= 3 -
at H+10) Under such circumstances external radiation will be the major
hazard, and water contamination will contribute significantly to the radi-
ation dose only where effective shelter is provided to reduce external
radiation exposure„
Calculations of the radiation dose to various organs due to ingestion
of water contaminated by fresh mixed fission products indicate that the
gastrointestinal tract is the most heavily irradiated organ of the body
under conditions of short time ingestionc
To determine permissible levels of activity in water under emergency
conditions, it is necessary to decide the radiation dose acceptable under
the circumstanceso If a dose of 100 rem to the G.I. tract in 10 days is accept-
able, water with an activity of 00h |ic/ml at D * 1 can be used for 10 days0
On the other hand, if the maximum acceptable internal dose is 1^ rem in a
90-day period, the acceptable water activity level at D + 1 is approximately
3 x 10"2 |ic/nil e There is little information available upon which to estimate
dose-effect relationships for radiation doses due to short time ingestion of
radioactive materials„
Many radiation biologists consider that the greatest hazard from
ingestion of mixed fission product radioactivity is due to the increase
in body burden of Sr°^ and that radiation damage to other organs and by
other nuclides is of secondary importance0
Therefore, during early times after fallout when external radiation
levels are highest the hazard from ingestion of a given amount of mixed
fission product activity is much less than for a comparable amount of
activity at later times when the percentage of Sr?° in the mixed activity
is greatero
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Radiocheraical studies of Nevada primary fallout in water further
indicates a preferential strontium dissolution five times greater than
beta emitters in general. This means that if the MFC is to be based on
strontium body burden, then a 001 nc/ml value should be lowered in pro-
portion to the degree of strontium fractionation0
In Appendix A are results of fallout studies made during the 1957
Nevada test series„ It also has computations of the levels of activity
of ideal fission product mixtures of various ages that would lead to a body
burden of J> MC of &r if used for one year together with estimates of
radiation dose to the gut and to the skeleton due to use of such water„
From these considerations it would appear that maximum permissible
concentrations of radioactivity in drinking water under military emergency
conditions might well be in the order of 001 jic/ml during the early period
after attack and that at later times considerably lower levels should be
permitted to guard against the accumulation of Sr° 0
It has been pointed out in earlier progress reports and in Appendix A
that conventional water treatment processes are relatively inefficient in
removing those soluble radioactive isotopes which present the greatest hazard
when ingested (10 to 70 percent, depending upon the isotopee) On the other
hand, they do effectively remove the insoluble particulate matter. If
further decontamination is required, only two processes are worthy of serious
consideration, namely, ion-exchange and distillation,,
For waters of mineral content suitable for drinking, distillation is
considerably more expensive than ion-exchange demineralization. Therefore,
consideration has been limited to various schemes utilizing ion-exchange
materials for removal of soluble radioactive contamination*
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-5-
The most significant fission products to be considered during "the
immediate period after fallout are Sr8?, Y?1, Zr?^, Mo", Ru103, Te132,
I131, I132, Ba3^0, La1**0, and the rare earths „ Since such a mixture
contains considerable amounts of hazardous radioactive anions, notably
iodine isotopes, removal of both cations and anions is required0 To do
this, a column of mixed cation-anion exchange resins is needed,, Such a
column will remove 99 percent of the radionuclides remaining in a normal
water treatment plant effluent„ The quantity and cost of these resins
will depend upon the mineral content of the water rather than its radio-
activity since most exchange sites will be occupied by stable rather than
radioactive ionse Break through of either type ion will occur at approxi-
mately the same time0
Long-Term Basis
As the fission products decay, a larger percentage of the activity
is due to the more dangerous long-lived isotopes, i.e0, capable of serious
internal damage., Outstanding among these isotopes is Sr°°0 As this occurs
the problem becomes one of protection against a long-term hazard0
It is not possible to predict to what extent decontamination facilities
are likely to be needed since surface water supplies are dynamic and individual„
The determination of need should be based on radiochemical analysis for such
nuclides as Sr" and Cs „ Treatment facilities need not be provided in
advance of demonstrated need0
Facilities and competence for such analyses should be available at
the Naval District level or arrangements should be made with other govern-
mental, or with private laboratories,,
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Treatment of water contaminated with the longer lived nuclides can
best be done with cation ion-exchange resinse
No consideration has been given to development of design criteria
for protection against radioactive materials covertly introducede They
have been dismissed as relatively unimportant since they appear unsuited
as a means of sabotage when compared to biological or chemical methods0
DESIGN CRITERIA
Where only surface water is available, conventional water treatment
processes must suffice for the large requirements likely to be needed for
decontamination of radioactive surfaces, and for fire protection. Ion-
exchange and distillation are not economically feasible as a treatment method
for these uses.
It is anticipated that for the first 10 days, the immediate period,
a supply of one gallon per person per day will suffice for drinking and
culinary purposes. This figure represents roughly 1/LOO of the average
water demand. For an installation with an average water use of ls000,000
gallons per day, it will be necessary then to supply 10,000'gallons per
day of water that is safe for drinking and culinary purposes . Ion-
exchange treatment is the most practical and economical method of supplying
this water o
Since the fresh fission products contain activity due to anions as
well as cations a mixed bed ion-exchange column will be required. The
anions are mostly short-lived isotopes and a cation bed alone will suffice
for the long-term requirements.
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TYPE, SIZE, AND COST OF UNITS
Immediate Demand
Although a centrally located and operated demineralizer could produce
water more economically than smaller more widely dispersed units, it has not
been considered as the most desirable solution because of the problem of dis-
tributing the watero At times when such treatment would be needed, it would
be most important to avoid all unnecessary exposure to external radiation,,
Distribution of a centrally treated supply for drinking and culinary purposes
by tank truck or other means would involve considerable radiation exposure to
personnel involved which could be avoided by providing numerous small demin-
eralizers in shelters or at other points of water use for decontaminating
the piped water supply,,
Small, mixed-bed demineralizers similar to those in common use in
laboratories would be equipped with disposable cartridges containing the
ion-exchange resins«, A sijnple conductivity meter or resin color change
would indicate the need for replacement of an exhausted cartridge. This
type of apparatus- is recommended to supply the immediate requirements for
all installationso
The typical cost estimates presented in Table I for small demineralizers
are based upon the following conditionsg
10 Total solids content of water to be treated is 10 grains
per gallon which is an average quality,, (1 grain per
gallon « l?ol ing/liter).
2o How rate of 5 gallon per hourc (2 gallon per minute/cu0 ftc)
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-8 *
3e Each demlneralizer cartridge has a capacity for 1100 grains
of dissolved solids0 (Approximately 10£ foot long and
2 inches in diameter0)
Uo Maximum cartridge changes of one per day. Discard each
cartridge safely since it will be radioactive and thus
not practical to regenerate.
TABLE I
COST OF DEMINERALIZING RADIOACTIVE WATER FOR SHORT TERM
Mater Demand
gpd
10,000
5,000
1,000
Cartridges
Required
per dayl
90
W
9
Initial Cost of
Complete Units
at $81 o each
$73000
36£00
730,
Operating Cost
Based on
Cartridge Needs
$ 870.
I3$o
87.
(9 cents/gal.)
on removal capacity,, Where the total solids in the
water are less, the operating cost will be Iess0)
It ie possible to use a much simpler throw-away ion-exchange cartridge
and holder, providing it is not put into a pressure line. The capacity for
such a model is 900 grains with a rate of 5> gph. The initial wall bracket
support, faucets, hose connections, etce would cost about $7o£0 each and
the replaceable cartridge about $9,500 Prices would vary with size of
order, but a 30 percent reduction is possible« This would reduce the
initial cost by a factor of ten, but the operating costs would be about
the same.
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,90
. 9 -
Long-Term Demand
Pressure cation-exchange beds operated on the sodium cycle are the
preferred method of decontaminating water for drinking and culinary purposes
where this is necessary on a long-term basis because of contamination by Sr
and other long-lived radionuclides. This equipment would normally be located
at the water treatment plant and operated by that plant's personnelo Where
/the water is comparatively soft, it may be economically feasible to treat
the entire water supply. Where the water is hard, it may be preferable to
treat only enough for drinking and cooking, and to make special provisions
for distribution of this water with proper sanitary precautions„
The cost estimates in Table II for such units are based upon the
following conditions?
le Hardness of water to be treated: 8 grains per gallon.
20 A maximum flow rate: 8 gallons per minute/ft „
3. A high capacity styrene resin will be used, such as Dowex-£0
or Amberlite IR-120,
ho Capacity of resin is 30 kilograins per cubic foot,,
5o Amount of regenerant required is 16 lbs« per cubic foot*
6. For maximum demand, regeneration would be required once a day*
TABLE II
COST OF DEMINERALIZING RADIOACTIVE WATER FOR LONG-TERM DEMAND
Aver. Water
Requirement
1000 gal.
per day
Max. Water
Requirement
1000 galo
per day
Tanks
No.
100 300 2
50 100 2
Dia.
ft.
Bed
Depth
ft.
Bed
Volume
ft3
Initial
Cost
Operating
Cost per
1000 gal.
U.5 2.52 80 $15,000 $ 0.1555
3 2.83 ho 10,000 0.175
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Costs will vary somewhat depending on water hardness and extent of
treatment required for a particular situation, and this can only be eval-
uated when the problem is at hand. These costs do not reflect the cost
of distribution of the water with proper sanitary precautions. At most
bases it will probably be more economical to obtain the necessary water
from safe ground water sources rather than to resort to this special
treatmente
BIOLOGICAL
HAZARD
A number of biological agents could be used quite effectively to
contaminate water supplies. The most effective method of using these
materials would be by their covert introduction into a water distribution
system0
If introduced into the raw water, normal treatment processes would
remove or destroy a considerable fraction of most biological agents; and
although they might not produce a completely safe water, they would provide
some degree of protection; or, conversely, an enemy would need to use
larger quantities of the agents to penetrate this defense.
Information on the casualty producing dose of most biological
agents is scant, but some is available0 This has been discussed in
previous reports. The agents which appear most effective for use as
casualty producers in water are the various vegetative pathogenic bacteria,
and botulinum toxin. It is not possible to rule out entirely the use of
pathogenic spore-forming bacteria, notably B. anthracis, but this organism
is not especially infectious by the oral route. If it were used, very
large doses of the agent would probably be required to produce casualties,,
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Viruses have been considered as possible water contaminants, but are
considered less suitable agents than bacteria or botulinum toxin. They are
more difficult to produce in quantity than bacterial agents or botulinum toxin,
particularly in the absence of specialized production facilities. There is
very little information on the infectious dosage of viral agents, but most
quantities of the viruses would probably be needed to infect a sizeable
proportion of the population via the water route. Epidemiologies! evidence
indicates that infectious hepatitis is the only serious virus disease frequently
spread by water. No method of growing this virus outside the human
body is known at present.
Our knowledge of the effectiveness of chlorine in inactivating viruses
is incomplete. The enteric viruses that have been studied show a wider spec-
trum of chlorine resistance than the vegetative bacteria. Some are killed
by very low chlorine doses, but some appear to be more resistant to chlorine
than vegetative bacteria „
Other biological agents might also be used but from the information
presently available, it appears that these mentioned above would present the
greatest hazard.
One potential agent which has not been considered in design is the
toxin found in some shellfish and produced by certain dinoflagelates such as
Gonyaulax catanella0 This poison has been responsible for more than 600 known
cases of poisoning and some 69 deaths. The toxin has been prepared in crystal-
line form and it may be possible to synthesize it but as present the only
source is infected shellfish or the organisms producing it. The lethal
dose to man as established from accidental human poisoning is approximately
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3-5 rag of the pure toxin. At present, production of large amounts of the
toxin would be very difficult and expensive, but if a suitable method of
synthesizing the compound could be developed, this would be an outstanding
agent for contamination of water or food.
The quantities of shellfish toxin available for use on this project
were sufficient to permit only limited study of possible water decontamina-
tion. This toxin is relatively stable to heat except at high pH. It is
removed by cation exchange materials, under certain conditions, and des-
troyed to some extent by chlorine dioxide. Details of limited studies
conducted at this Center on the effectiveness of chlorine and chlorine
dioxide in destroying shellfish toxin are presented in Appendix B.
No method is available for quickly detecting contamination of water
by biological warfare agents. For this reason any protective measures
taken must be routine once it has been determined that danger of an attack
exists.
The closest approach that exists for quick detection of BW contamina-
tion is through continuous measurement of free chlorine residuals. Since
most of the suitable biological agents arekilled or inactivated by
chlorine, an enemy would probably introduce a dechlorinating agent along
with the BW agent.
If chlorine residual levels in the distribution system are suf-
ficiently constant or slowly varying and if they are normally sufficiently
high to cause appreciable destruction of BW agents, this procedure could
provide some warning and a degree of protection. Relatively little in-
formation is available on the normal variation of chlorine residuals in
water distribution systems. To obtain some information on this question
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automatic chlorine residual recorders were operated at two Public Health
Service installations located at different points on the same distribution
system. At one location chlorine residual levels varied slowly and never
approached zero. At the other location, however, there were frequent
periods of zero residual and variations were wild and precipitous. Varia-
tions from zero to several mg/1 occurred in 15 minutes or less on a number
of occasions.
Thus the feasibility of relying on a chlorine residual recorder
to warn of contamination by BW agents would have to be determined by study
of each situation.
Several methods of disinfection for protection against BW agents
have been considered and reported on in separate reports. The ones which
hold the most promise are chlorine, chlorine dioxide, and heat. Each has
its advantages and disadvantages for a particular situation. The effective-
ness of all three are a function of concentration and time.
Chlorine
The relationship between free available chlorine concentration (C)
and chlorine contact time (t) for a stated kill (other variables constant)
is usually expressed by Cnt = K. The value of K depends on the organism to
be killed, as well as pH and temperature. For vegetative bacteria, it is
very low; for bacterial spores, it is high; and for botulinum toxin, it is
between these two extremes.
When using free available chlorine, the active agent mainly respon-
sible for destruction of both spores and vegetative bacteria is undissociated
HOC1, (hypochlorous acid). When HOC1 ionizes to H* and OC1~ in water, it
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loses most bactericidal properties. At pH values above 7.0 this ioniza-
tion becomes appreciable. For this reason, the pH of water must be held
in the range from 6.0 - 7.0 for efficient spore kill. For vegetative
bacteria, no pH adjustment is considered necessary unless the pH is in
excess of 9.£. The ability of free chlorine to destroy botulinum toxin is
not markedly effected by pH. Most water will have a "chlorine demand"
that must be satisfied before free available chlorine residuals will exist.
It is necessary then to measure free chlorine residuals after the contact
time has been provided. Combined chlorine residuals are much less ef-
fective against all of these agents and cannot be recommended.
The actual operating residual necessary to kill vegetative bacteria
rapidly is generally only a fraction of a mg per liter. Although the
resistance of toxins to chlorination varies widely, all five types of
botulinum toxin tested in this laboratory were at least 99.9 percent des-
troyed in five minutes or less by providing a free available chlorine
residual of 1 mg/1.
Bacterial spores are many times more resistant to chlorination
than vegetative bacteria. Higher chlorine concentrations, longer contact
times and special attention to pH control are needed to protect against
spores. Because of these special requirements and because of the doubt-
ful effectiveness of B. anthracis as a water contaminant separate recom-
mendations are included for protection against bacterial spores.
Chlorine is the standard water disinfectant and there is a con-
siderable background of experience in its use. Reliable equipment is readily
available to feed chlorine at rates proportional to flow. Automatic chlorine
residual recorders are available which will differentiate between free and
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- 15-
combined chlorine.
Chlorine dioxide
Chlorine dioxide is somewhat more effective than free available
chlorine in destroying botulinum toxin. A major advantage of chlorine
dioxide is that it does not react as chlorine does with ammonia that may
be present. This means less chlorine dioxide will be necessary to destroy
the harmful ingredient, toxin.
The principal difficulties which prevent recommending it instead
of chlorine are incomplete knowledge as to its effectiveness as a bacteri-
cide and uncertainty as to methods of measuring chlorine dioxide residuals
in water. It is also more expensive than chlorine.
Heat
Heat is the oldest most widely used and probably the most reliable
method of disinfection. Pathogenic vegetative bacteria and viruses are
killed in a few seconds at 70°C. Botulinum toxin requires temperatures in
the neighborhood of 80 - 100°C for rapid destruction. Shellfish poison can
be destroyed by heat at pH's above 9.0. Bacterial spores require much
higher temperatures.
Reliable automatic equipment for controlling heat disinfection
processes is readily available* The operating cost is high as compared
with chemical water disinfection even though heat exchangers may be used
to recover much of the heat. Equipment cost is also high as compared with
that needed for chemical disinfection except for very small installations.
Appreciable variations in flow make for greatly decreased efficiency of
operation and increased equipment cost of heat disinfection.
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For very small installations where freedom from operation problems
is of prime importance heat has considerable merit. Heat exchangers
designed for very small installations} such as, individual homes, rural
schools, isolated recreation areas, etc., are under test at the Sanitary
Engineering Center and results are encouraging. These must operate at a
low rate for a high percentage of the time in order to be reasonably
economicalo This requires storage and pumping in order to provide water
at demand.
For general use the high cost of heat treatment of water makes it
less desirable than chlorination. For small installations or for special
portions of larger installations, it may be reasonable in cost.
It should be emphasized that although the recommendations made for
protection against various biological agents are believed to be adequate,
it is not possible to give absolute assurance on this. The possibility
of development of more dangerous or more chlorine resistant strains of
particular organisms exists, as does the possibility of developing feasible
methods of producing materials such as shellfish toxin and infectious hepa-
titis virus which have not been considered as potential agents at this time.
DESIGN CRITERIA
Raw Water Contamination
Somewhat less attention has been paid to the details of protection
against raw water contamination since it can be more easily handled than
contamination of finished water. As a means of conducting biological
warfare, contaminating a raw water with a biological agent could not be a
notable effective method, especially since one of the prime purposes of a
water treatment plant is to remove micro-organisms. Nevertheless, suggested
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protective measures are presented here to illustrate how existing treatment
plants may be strengthened or altered to cope with various BW warfare
agents introduced into a raw water supply.
For vegetative bacteria and botulinum toxin separately or together
these measures are:
1. Chlorinate the raw water so there is a free available
chlorine residual of 0,6 mg/1 in the influent to the filters.
2. Monitor this residual by providing a continuous, automatic
chlorine indicator and recorder.
3. Arrange for the instrument to sound an alarm when the residual
drops below 0.5 mg/1.
k» If free residual chlorine drops below 0.5 mg/L prior to fil-
tration, increase chlorine feed to overcome decrease and increase
post-chlorine feed to give 1.0 mg/1 free chlorine residual in
the water leaving the plant.
5. At other times post-chlorinate to maintain a residual of 0.5 mg/1
i '
in the water leaving the plant.
These recommendations are based on an assumption of a pH level below
9.5 and a nominal detention time between prechlorination and filtration of
not less than 2 hours.
This treatment will be adequate except in lime softening plants
where the pH may be too high for effective bactericidal action of chlorine
at these recommended dose levels and in plants using upflow clarifiers
with short detention periods.
In plants where the normal fluctuation of chlorine demand is ap-
preciable, somewhat higher residuals than are recommended above may need
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to be carried routinely in order to prevent too frequent drops below the
alarm level of 0,5 rag/1.
The cost of this protection is relatively low. The largest equip-
ment item would be an automatic indicator, recorder, and alarm which would
cost about $3500 for any size installation. Larger chlorine requirements
would be the principal operating expense.
For protection against bacterial spores the special measures are:
1. Chlorinate the raw water so as to maintain a 17 mg/1 residual
°^ fr'gg available chlorine in the influent to the filters.
The nominal flow through time of 2 hours will provide enough
contact time to affect a 99.9 to 99.99 percent inactivation of
spores.
2. Monitor this residual with an automatic and continuous chlorine
residual indicator and recorder, equipped with an alarm to indicate
when the residual drops below 15 mg/1.
3. Provide an automatic and continuous pH indicator and recorder
4. •
with an alarm. It should also be placed just ahead of the sand
filters to make sure the pH is no higher than 7.5 since disin-
fection action is impaired in a higher pH range.
kc Provide sulfur dioxide feed for reducing the final chlorine
residual to 0.5 mg/1.
5. If either alarm is sounded take the necessary corrective action
and discontinue dechlorination.
As illustrated in Figure ] and in Appendix E, the estimated cost of
providing this supplemental treatment will vary from $22 per day for 0.5 MOD
to $215 per day for 10 MOD.
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i i i i i r
250
200
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- 20 -
Finished Water Contamination
The principal design problems in protection against BW contamination
of a water distribution system near the point of use arise from the de-
sirability of carrying out the decontamination process on a continuous flow
basis without appreciable pressure loss and as nearly automatically as
possible. Repumping after treatment would increase considerably the cost
and operating complexity of the procedure.
Special attention is needed in designing an efficient chlorine
contact tank to assure that all water is held for a time sufficient for
the chlorine to act. Short circuiting in such a tank could permit inade-
quately treated water to reach the consumer. A number of possible designs
have been studied. The one that appears most suitable uses a tank filled
with a coarse granular media such as pea gravel.
Measures that must be taken against covert introduction of vege-
tative bacteria and botulinum toxin are:
1. Superchlorination
2. Detention
3. Dechlorination with activated carbon
A flow diagram of such a treatment unit would be as follows:
BW Agent
Added
1
•^ 1 X-
^ Finished Wate*r
in a System
b
Flow
Rate
Meter
Chlorine
Contact
Device
>
t
Chlorine Chlorine
Feed Indicator. Recorder
Carbon
Filter
. and
'To Point
of
Consumption
Alarm
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Flow Rate Meter; The primary purpose of the flow meter is to pro-
vide the control signal for the chlorine feed. Either a propeller type
or a positive displacement type meter should be selected, depending on
the rate of flow. It should be capable of proportioning feed over the
range of flows expected. Where this is greater than 10 to 1, the meter
should be chosen to signal accurately at peak flows and, if necessary,
overfeed at low flows,,
Chlorine Feeder; For small installation, a pump of the proportioning
type to feed calcium hypochlorite solution is preferred, since it is cheaper
and does not require special safety precautions such as are needed in handling
gaseous chlorine. It will be more economical to use gaseous chlorine for
large installations. In either case, the device must be capable of pro-
portioning the feed over the range of flows to be expected. Sufficient
chlorine must be added so that a free chlorine residual of at least 1 mg/1 is
maintained throughout the chlorine contact time.
Chlorine Contact Device; The details on the developing and testing
of this special chlorine contact tank are given in Appendix D. The con-
struction cost of such a device is illustrated in Figure 2 as it varies with
size and detention time. For example, it would cost about #11;,000 to
build a tank to handle 1 MOD with a 5-minute detention.
Chlorine Indicator, Recorder, and Alarm; This instrument will con-
tinuously record the free chlorine residual of the water at the outlet of
the chlorine contact device. In the event of a covert attack, a de-
chlorinating chemical can be expected to accompany a biological agent.
An alarm, activated by this instrument, should be provided to warn of this.
-------
- 22 -
120,000
100,000
90,000
CO
b
nJ
o
O
40,000
20,000
60-minute detention
5-minute detention
0.250 0.500 0.750
Average Flow Rate MOD
1.00
1.25
ESTIMATED COST OF CONSTRUCTING GRAVEL FILL CONCRETE
TANK FOR USE AS CHLORINE CONTACT TANK
Figure 2
-------
- 23-
Activated Carbon Filter; Pressure type, granular carbon filters are
provided to dechlorinate the water. They should be 30 inches deep, and
designed for 3 gal/ft /min at the maximum flow rate. The carbon will, in
addition, provide sane protection against chemical warfare agents. A
discussion of the engineering practicability of dechlorination by using
activated carbon filters is given in Appendix C, Part I; and Part II
summarizes the work done here on using these filters to remove botulinum
toxin.
A special building to house the equipment will be unnecessary for most
installations, since it is compact and a suitable space can probably be
located in existing structures. The detention tank can be placed under-
ground or at ground level out-of-doors.
To provide protection against the covert introduction of bacterial
spores, a few additional devices and chemicals must be used so that the
entire flow diagram would be:
Bacteria
Spores
Incoming^!
Water
1
Flow
Meter
- I
Acid C]
Feed Fe
t
ed
Chlorine
Contact
Device
Indicator
Recorder
& Alarm
1,
1
f
Carbon
Filter
pH
Indicator Sods
Recorder Ash
& Alarm Feec
fy^ To point
of con-
sumption
pH
L Indicator
Recorder &
L Controller
The function and size of each unit would be similar to those dis-
cussed previously except for control of pH.
-------
- 2U-
Acid Feed; A proportioning feed pump should be provided to add acid.
The pump will be controlled by the signal from the flow rate meter, and
should be capable of adding sufficient acid to insure a pH of 6.0 - 6.2
at the peak flows. Acid feed will not be required at every installation
since pH of many water supplies will be sufficiently depressed by the
chlorine feed alone.
Chlorine Feed; A device to feed gaseous chlorine should be provided.
Chlorine gas will aid in depressing the pH and is more economical.for
this type of installation than hypochlorite. The chlorinator must be of the
automatically proportioning type since it will be controlled by the flow
meter, and capable of feeding accurately at the maximum flow rate expected.
A free chlorine residual of at least 15 mg/1 must be maintained after the
contact time0 The amount added will be more than this, of course; it
will depend on the chlorine demand of the water and whether or not chlorine
is the only chemical added to depress the pH. In many cases, this will be
found more economical than installing and operating acid feed equipment.
Chlorine Contact Device; A chlorine contact tank filled with pea
gravel should be provided to detain the maximum flow for at least one hour.
The design, construction and cost of this device is given in Appendix E.
i
Soda Ash Feed; A proportioning feed pump is provided to feed soda
asho The pump will be controlled by a signal from Hie pH instrument to
follow. Soda ash is necessary to increase the alkalinity and pH of the
water after dechlorination and to reduce its aggressiveness. The pump
should be capable of proportioning over the range of flows expected.
pll Indicator, Recorder, and Controller; This instrument will
originate the control signal for the soda ash feed pump. It should be
-------
- 25 -
capable of controlling over the range of flows to be expected. In addition,
the instrument will provide a permanent record of the pH of the water dis-
tributed for consumption.
For most installations, a special building to house the equipment
will be required; the size will, in effect, depend on the flow.
As indicated in Figure 3* the daily cost of this retreatment against
spores varies with flow from $U3 per day for 0.1 MOD to $268 per day for 1 MOD,
On the other hand, for other BW agents the cost would be only $16 per day
for 0.1 MGD to $9U per day for 1 MOD.
For estimating costs, only the prices of water treatment equipment
commercially available have been used. Equipment has been amortized over
10 years at 2.f> percent interest. In addition to the major items of
equipment, the cost includes estimates of:
1. Installation (in the U.S.)
2, Necessary piping for hookup
3. Miscellaneous equipment likely to be required for operation
U. Maximum daily chemical use.
Detailed cost figures for all types of treatment are presented in
Appendix E.
CHEMICAL
HAZARD
As covert contaminants in finished water, available chemical war-
fare agents generally would be less suitable than biological agents.
Most chemical poisons are relatively quick acting at levels which would
cause casualties and their presence would probably be noted before a
large fraction of the potential water users would be affected. In addition,
-------
.26-
300
250
200
S
m
« 150
U 100
50
Bacterial Spores
Vegetative Organisms
Botulinum Toxin
I
I
0.250
1.00
0.500 0.750
Average Flow Rate MOD
ESTIMATED RETREATMENT COST
1.25
Figure 3
-------
- 27 -
the oral toxicity of even the nerve gases (among the most potent chemical
agents) is such that comparatively large quantities of material would be
required to contaminate a water supply.
Contamination of a raw water source with chemical agents would
require more material than contamination of a finished water and would be
a less effective method of reaching the target population. Raw water
•
contamination incidental to use of chemical agents in air is, however, a
possibility and provision for emergency measures to deal with this con-
tingency should be provided.
The Army Chemical Corps has developed a kit for detection of the
common CW agents in water „ This kit, stocked by the Navy Department,
would be particularly suitable for use at water treatment plants for de-
tection of contamination of the raw water Incidental to a general CM
attack.
To detect covert attacks using chemical agents, some type of con-
tinuous monitor would be desirable. As a possible device for this use, a
continuous bio-assay technique using fish has been developed at this Center.
(See Appendix F for details). Fish are much more sensitive than humans
to many chemical contaminants, and they are particularly sensitive to the
nerve gases. Concentrations of the nerve gas GD in water which can be •
tolerated by humans are rapidly lethal to fish. The procedure is sub-
ject to some "false alarm" difficulties since certain materials harmless
to humans are toxic to fish. This procedure is not suited to detection of
biological warfare agents. Fish are not sufficiently affected by botulinum
toxin or staphylococcus enterotoxin to be useful for detecting these two
potential agents.
-------
- 28 -
There are no economically feasible water treatment methods which
could be routinely applied to a water supply to remove or destroy all
known chemical warfare agents. Granular activated carbon filters, such
as are recommended for dechlorination in the protection against BW agents,
will provide some protection against many chemical agents and are about
as close an approach to a general protective device as is available. (See
Appendix C, Part III). Specific decontamination procedures, which have
been worked out by the Army Chemical Corps, will be required when contam-
ination is discovered and the agent identified. For nerve gases this is
accomplished by adjusting the pH to promote rapid hydrolysis which reduces
the toxicity of nerve gases.
DESIGN CRITERIA
In developing general design criteria major consideration has been
given to protection against the nerve gases in water. It should be
pointed out, however, that the possibility of using still other known
chemicals does exist, as well as the possibility of development of new
agents. Since decontamination procedures must be tailored to the parti-
cular chemical involved, it is not feasible or even possible to prescribe
a routine or single treatment method suitable for all agents.
Raw Water Contamination
As indicated previously, the most practical basis for counter-
acting nerve gases in water is to raise the pH to increase the rate of
hydrolysis „ This would be done routinely where the water is softened by
a lime-soda ash process. In other cases, an alkali such as lime or soda
ash could be added to a raw water when detection methods indicate nerve
-------
-29 -
gas contamination. The resulting high pH, of course, would greatly re-
duce the disinfecting power of chlorine and hence would not be desirable
if concurrent EW contamination was suspected.
Finished Water Contamination
The activated carbon filters designed for dechlorinating and dis-
cussed previously will help to remove the nerve gas GB. However,''instailing
these filters specifically for chemical warfare agents would not be practi-
cal since there are other CW agents that would not be removed by activated
carbon. The activated carbons most suitable for removal of chemical war-
fare agents are not the most suitable for dechlorination and vice versa.
SUMMARY
It is difficult and costly to design and operate a treatment plant
to protect all water from all possible biological, chemical, and radio-
logical warfare agents. It usually will be practical to protect only against
the most likely incidents and agents. These possibilities appear to be
primary fallout from high-yield nuclear devices, and covert introduction of
vegetative bacteria or botulinum toxin into finished water.
During the immediate period following heavy contamination of a
surface water supply by radioactive fallout the most feasible method of
decontamination of the water will be by small mixed-bed ion-exchange
columns. Such a column will remove about 99 percent of the soluble
radioactivity from the water. This treatment will cost approximately
$0.10 per gallon so it should be limited to water for drinking and food
preparation. These .treatment devices should be located in shelter areas
near the point of water use.
-------
- 30 -
Chlorination with free available chlorine residuals of 1 mg/1
will suffice to handle most BW agents, but the time, temperature and pH
all have some influence on its effectiveness. A detention device made up
of a reinforced concrete tank filled with pea gravel will serve to obtain
the maximum use of chlorine in the shortest time when installed in a
finished water pressure system. In conjunction with this device, it would
be necessary to have equipment that would control the chlorine residual and
in some cases the pH. This type of retreatment would cost $16.00 per day
for 0.1 MOD and would need to be operated routinely when there is reason
to believe danger of a BW attack exists.
-------
- 31 -
APPENDIX A
FALLOUT STUDIES
Samples of fallout from the Nevada ballcoashot "Priscilla", detonated
June 2k> 1957, were collected in fallout trays at various distances from
ground zero and put through a size separation process to obtain particles
in three size ranges, <5 microns, 5 to 50 microns, and >50 microns. The
samples were shipped to this Center for solubility tests and radiochemical
analysis. The field work was done jointly with representatives of the
Corps of Engineers, Engineer Research and Development Laboratory.
TEST PROCEDURES
A gross beta activity determination was made on each sample by
counting -the radioactivity in a raw soil portion with a GM countermand
also in an acid-dissolved portion with an internal, gas-flow, proportional
counter. Decay rates on these samples were determined over a 6-month
period.
Another portion of each soil sample was mixed thoroughly with
10 liters of distilled water for 1 to 2 minutes daily and then allowed
to stand. The pH was adjusted to approximately 7 by adding a small
amount of IN HMO.,-
To obtain a representative sample of this slurry a rapid mixer was
used for a few minutes before and during the siphoning of two 100 ml
portions. These duplicate samples were filtered through a membrane filter
to separate the suspended solids. Both tiie suspended and liquid portions
were dried, plated, and assayed for gross beta activity with an internal
proportional counter. The same sampling technique was employed to obtain
portions for subsequent radiochemical analysis.
-------
- 32 -
SOLUBILITY OF FALLOUT
As indicated in Table I, about 10 percent of the radioactive
material in each particle siz e range usually went into solution. However,
the fine dust (<5 microns), at approximately U,000 yards from ground zero,
was only about 3 percent soluble. There is no apparent reason for this low
value especially since the particles in the same size range from a near
ground zero sample were ID percent soluble. The activity per unit weight
of this fine dust was 10 to 30 times higher than in the other fractions .
The percent of radioactive material soluble in each case did not
change significantly over a h to 5 month period. The radioactive decay rate
for the suspended solids was similar to the rate for the soluble portion.
RADIOCHEMICAL ANALYSES OF SOIL AND WATER
The chief objective of this study was to determine if there is any
large preferential dissolution of the internally hazardous radionuclides
associated with fallout. The low level of activity in most of the samples
made it necessary to work with large quantities of soil and this in turn
complicated the chemical manipulations and counting. "Thus it was not
possible to get satisfactory results for all the Individual radionuclides
present. However, Table II does indicate that the dissolved solids contain
about £ times as much radioactive strontium as would be expected if all of
the nuclides in the dry fallout material were equally soluble in water.
In addition further fractionation of strontium usually occurs during the
conventional water treatment process.
Table III shows the levels of activity of ideal fission product
mixtures of various ages that would lead to a body burden of 5 nc of Sir
if used for one year together with estimates of radiation doses to the gut
and to the skeleton due to use of such water.
-------
- 33 -
TABLE I
SOLUBILITY OF PRIMARY FALLOUT
NEVADA TEST, JUNE 2U, 1957
Sample
Size in ^ Source
Date
Counted
Gross Beta Radioactivity
in woe/rag
Suspended
Solids
Dissolved
Solids
S.S.
& DS
Percent
DS/~SS+DS
<5
5-50
>5o
<5
>50
30 yards
from
Gr. Zero
30 yards
from
Gr. Zero
30 yards
from
Gr. Zero
UOOO yards
from
Gr. Zero
5-50 UOOO yards
from
Gr. Zero
UOOO yards
from
Gr. Zero
8/2U/57
10/2V57
12/2U/57
8/2U/57
10/2U/57
12/2U/57
8/2V57
10/2V57
12/2U/57
7/2V57
8/2U/57
10/2U/57
U/2U/57
7/2U/57
8/2U/57
10/21/57
11/2U/57
7M/57
8M/57
10/2 V5 7
11/2U/57
UU.
2U.
18.
39.
2U.
16.5
23.
17.
llOO.
170.
69.
U8.
23.
10.
U.2
3.0
11.
5.
2.1
1.5
U.9
2.6
1.8
3.7
2.2
1.5
U.U
2.3
1.6
U.
6.
1.5
0.9
U.o
1.7
0.56
0.36
1.6
0.75
0.30
0.20
U8.9
26.6
19.8
U2.7
26.2
18.0
IiU.li
25.3
18.6
uu*.
176.
70.5
U8.9
27.0
11.7
U.76
3.36
12.6
5.75
2.UO
1.70
10.
9.8
9.1
"8.7
8.U
8.3
9.9
9.1
8.6
3Ji
3.5
2.2
1.9
12.
1U.
12.
11.
13.
13.
12.
12.
-------
TABLE II
RELATIVE SOLUBILITY OF STRONTIUM IN WATER
NEVADA TEST SHOT, JUNE 2k, 1957
Sample
Size
in jj.
Source
Date
Gross Beta
in soil
[Hic/mg
Strontium
in soil
H4ic/mg
Ratio^=
G-Bsoil
Srsoil
.Gross Beta in
Soluble Portion
J41C/1
Strontium in
Soluble Portion
mic/1
RatiO2=
G'B°water
Srwater
Ratio^=
Ratio^
Katio2
< 5 30 yds. V2V58 22
from
Gr.Zero
5-50 30 yds. U/21/58 22
from
Gr.Zero
>50 30 yds o Ii/21/58 1?
from
Gr.Zero
0.11
0.18
200
160
110
2500
2100
1700
68
70
73
37
30
23
5.3
U.8
-------
TABLE IH
GROSS FISSION PRODUCT ACTIVITY (tic/ml) AND DOSE (rep)
TO GUT AND SKELETON AT VARIOUS TIMES
Age at Start
of Use
Gross Fission Product
Activity for 365 Day
Consumption*
Total Dose to Dose to Skeleton***
Gut** for 365 Day Comsumption For 365 Day Consumption
(All Fission Products) Dose During 1st Yr. Dose to Infinity
1 Day 1.1 lie/ml
10 Days 7.0 x 10"2 jic/ml
30 Days 2.0 x 10"2 pjc/ml
90 Days 5»0 x 10~3 puc/ml
365 Days 9.5 x 10'^ uc/ml
* Consumption for
750 rep 195 rep 675 rep
500 rep 165 rep 650 rep
335 rep 125 rep 600 rep
185 rep 55 rep 550 rep
70 rep 5 rep 500 rep
365 days will accumulate a Sr90 body burden of 5.0 jic
** Dose from all fission products to large bowel (assumes no G.I. absorption)
89
*** Dose from Sr ,
Sr90-Y 9°, Sr91-Y 91, Zr9*-Nb95, Ba^-La^0, and rare earths.
f
%r>
-------
- 36-
From these considerations it mould appear that maximum permissible
concentrations of radioactivity in drinking water under military emergency
conditions might well be in the order of 0.1 to 1.0 nc/ml during the early
period after attack and that at later times considerably lower levels
should be permitted to guard against the accumulation of Sir .
Inasmuch as the Sr^° body burden is seriously considered as a
limiting basis for ingestion, the indicated fractionation of strontium
has some significance. It could mean, for instance, that if the present
gross activity MFC value were 1.0 ue/ml for D * 1, then this gross value
should be lowered 5 to 10 times or to 0.1 jic/ml, so the Sr° body burden
in one year would not exceed 5 uc.
No specialized equipment for the monitoring of low levels of
contamination in water in the presence of high gamma ray background is
in existence at the present time. However, discussions between the Corps
of Engineers and the Signal Corps have indicated a probe type instrument
which can be immersed into the water under examination might best be
suitable to satisfy the present requirement•
No construction details for such an instrument have been worked
out at this time, but it is possible to predict the performance and the
limitations of this type of probe from basic considerations. It will
probably be desirable to equip this instrument with two detectors, one
of which is sensitive only to gamma radiation (from the water under
examination and from background radiation); the other sensitive to the
aforementioned gamma radiation plus the beta radiation from the water
contamination. Special circuitry in the instrument provides for sub-
traction of the gamma only, from the gamma plus beta, resulting in a
beta only indication. The beta background from the "surrounding" or
ambient radiation can be neglected because it is completely shielded by
-------
- 37 -
the water into which the probe is immersed.
A brief calculation below shows that under these circumstances,
it will be possible to measure contamination down to 10~^ nc/ml or even
10~^^c/ml if no appreciable outer gamma background is present. A
sensitive detector of the Geiger-Mueller or scintillation type should be
used, but details are not critical. In the presence of a high gamma
outer background, the sensitivity of the detector will be reduced. It
is estimated that in an external field of 1 r/hr, contaminations down to
10~2 to 10~^ nc/ml will be measurable. In a field of 10 r/hr, contami-
i —?
nations down to 10 to 10~ p.c/ml are possible of measurement.
•
It is not believed that in the present state of the art a much
greater sensitivity can be achieved by using other methods o f monitoring
at the point of interest. Methods of differentiation between different
radioisotopes by purely physical means are so complicated that they need
not be considered in this connection. Examination of water samples at
rear locations with low radiation background; e.g. by boiling down of the
water will of course lead to much higher sensitivities. All presently
known radiac instruments measure only the gross dose rate. Chemical
separation methods will have to be used if a detailed determination of
special isotopes is proven to be necessary.
SAMPLE CALCULATION
It is assumed that an extended body of water is uniformly con-
taminated with C microcuries of activity per milliliter of water. The
gamma ray dose rate will then be constant throughout the water in all
points not too close to the surface and is given by:
-------
-38-
(1)
D. R. - - •-»" dr
D. R. = dose rate in mr/hr.
C - activity concentration In
|i = gamma ray absorption coefficient in cm~ .
F = conversion factor from activity to dose rate.
F depends on the energy of the gamma radiation and the true ab-
sorption coefficient of air at tiiis energy and is of the order of 5 for
gamma radiation of 1 Mev. Since p. is of the order of O.Qt* at this
energy,
(2) D.R. = 500 #"C
which means a dose rate of about 1/6 r/hr for an activity concentration
of 1 tic/ml. The beta dose rate which corresponds to this contamination
is of the same order of magnitude as the gamma dose rate because the
much larger absorption p. of the betas is compensated by a correspondingly
larger specific ionization in the detector (larger F.).
If only the natural background is present, dose rates of less than
0.1 mr/hr can be easily detected with senstive detectors. This means,
according to equation 2, that contamination of the order of 10~^ nc/ml
should be detectable under these circumstances. The existence of strong
additional gamma fields introduces the problem of measuring the beta
radiation from the contaminated water as the small difference of two large
readings. The higher minimum activities given in the text for specified
gamma background levels are obtained if a beta dose rate equal to one or
a few percent of the gamma dose rate are considered as measurable. Be-
cause of the absorption of gamma radiation of outside origin within the
-------
- 39 -
water, the accuracy of the activity determination increases with increasing
depth of immersion of the probe.
DECONTAMINATION BY NATURAL AND CONVENTIONAL TREATMENT
Plain Settling
Table IV indicates that where settling takes place for 16 to 2h
hours, there will be a 62 to 92 percent removal of the radioactive
material. Hence, an open reservoir will serve as a good protective
device in removing particulate matter. From other fallout studies at this
Center, it appears that any radionuclides in rain or fallout on land will
be 90 percent retained on vegetation or soil and 10 percent washed into
surface supplies during normal runoff. This retention percentage is
approximately the same for activity associated with either solids or liquid,
Thus a sizeable fraction of fallout radioactivity would be removed before
reaching a water treatment plant.
Coagulation
Supernates from the overnight settling process were coagulated
with 20 mg/1 of ferric chloride plus lime when necessary to adjust the
pH, but the success of any chemical treatment was very poor, removals
varying from U to 76 percent depending somewhat on the addition of lime.
Based on previous experience with radioactivity in ionic form, this was
to be expected. Complete softening with a lime-soda ash process or high
pH, phosphate coagulation will usually do much better, especially on
such radionuclides as strontium.
-------
TABLE IV
REMOVAL OF RADIONUCLIDES FROM MIXTURE OF FALLOUT AND WATER
BY SETTLING, COAGULATION AND FILTRATION
NEVADA TEST SHOT, JUNE 2U, 1957
Sample
Particle
Size
Microns
Source
Date
Counted
Gross Beta
Radio-
activity
mic/1
Plain
Sedimentation
Gross Beta
Remaining
tWi
Percent
Removal
Coagulation of Settled Water with
20 mg/1 of FeCl3
Gross Beta
Remaining
liUC/1
Initial
PH
Lime
added
mg/1
Final
pH
Percent
Removal
Filtration of Raw
Mixture by Membrane
Filter
Gross Beta
Remaining
Wic/1
Percent
Removal
< 5 30 yds 9/2U/57
from
Gr.Zero
5-50 30 yds 9/2U/57
from
Gr.Zero
> 50 30 yds 9/2V57
from
Gr.Zero
< 5 HOOO 8/20/57
yds.
from
Gr.Zero
2/2V58
5-50 UOOO 8/20/57
yds.
from
Gr.Zero
2/2V58
> 50 UOOO 8/20/57
yds.
from
Gr.Zero
2/2U/58
71,000 27,000 62 23,000 8.3
79,500 2U,500 69 23,600 8.3
67,000 33,000 6U 28,000 8.1j
31,000 2,600 92
7.1 15
7.0
900 6.7 26 6.8 65
U,000 (Re-run on remaining portion of sample)
15,000 2,UOO 8U 1,500 7.2 7 7.2 38
2,1*00 (Re-run on remaining portion of sample)
lii,000 3,800 73 900 7.8 7 7.8 76
2,700 (Re-run on remaining portion of sample)
7,000
7,000
7.3 15 6,100
970
t/
110
1,900
200
2,000
90
91
89
97
97
87
92
86
9U
-------
-Ill-
Filtration
By rising a membrane filter, it was possible to remove all sus-
pended material from a mixture of fallout and water. A conventional sand
filter would be somewhat less efficient so filter plants could not hope
to remove much more than 8£ to 90 percent of the activity.
When combined serially, the normal water treatment processes will
remove most of the radioactive particles, but only about 10 to 70 percent
of the dissolved radionuclides.
Ion-exchange resins can be used to reduce the dissolved material
by 99 percent. Since extensive research had been done previously on
the efficacy of ion-exchange resins for removing radioactivity, no further
tests were made during this project*
-------
- U2-
APFENDU B
The Effect of Free Available Chlorine and Chlorine Dioxide
upon Shellfish Poison (Aqueous) at pH 7.0 and 25°C.
by
A« R. Brazis, A. R. Bryant, P. Kabler, and R. L. Woodward
INTRODUCTION
Shellfish poisoning has been recognized as a problem for many years
along the eastern and western coastlines of the United States and Canada.
Although the poison is not harmful to shellfish, only a few milligrams are
fatal to man.
There is no known antidote for shellfish poisoning. It is not af-
fected by ultraviolet irradiation. When the poison in acid solution was
held at 100°C. and treated with hydrogen peroxide, there was instantaneous
inactivation. The poison is not adsorbed on aluminum hydroxide at different
pH levels. Common sea sand, free from electrolytes, adsorbed approximately
90 percent of the poison from aqueous solution and little or none from an
alcoholic solution. In aqueous solution, exposure to pH 6*6 and 11 «5 for
six days resulted in 35 and 7U percent loss in toxicity, respectively.
Little is known concerning its resistance to disinfectants.
METHODOLOGY
The resistance of the shellfish poison has been evaluated in the
presence of chlorine dioxide and free available chlorine at pH 7»0 and
storage at 25° C. for two hours. Five hundred ml aliquots of the poison
have been exposed to 2.0 mg/1 chlorine dioxide, at concentrations of U.7
and hi micrograms (ug) per ml of solution. Equal aliquots of the poison
have also been exposed to free available chlorine.
-------
-1*3-
Measurement of the toxicity of the poison was made using the''mouse
bioassay method based on median death times of 5-7 minutes. Dilutions of
the poison were necessary to induce death in White Swiss mice, weighing
/
19-21 grams, so as to occur within the designated death times. At the time
of mouse inoculation, the poison was adjusted to pH 3*0. The poison used
during this study was thought to be chemically pure.
Determinations of the chlorine dioxide and free available chlorine
concentration and preparation of the buffered test water were the same as
•those used during an investigation concerning the resistance of Clostridium
botulinum toxins. During this investigation, the buffer capacity and
neutralizer (sodium thiosulfate) concentration were decreased to produce a
neglibible salt effect upon the stability of the poison.
A buffer concentration of 0.01 molar and neutralizer concentration
of O.Ol* percent did not affect the toxicity of the poison under the condi-
tions of the study.
Intervals of sampling were 15, 30, 60, and 120 minutes of exposure to
either chlorine dioxide or free available chlorine. Samples were collected
and placed in neutralizer, adjusted to pH 3oO, and inoculated into mice
the following day. Control samples were handled similarly.
RESULTS
Exposure of h»7 mg/1 shellfish poison to 2.0 mg/1 chlorine dioxide,
added initially, at pH 7.0 and 25°C., produced greater than 93 percent
inactivation of the poison within 2 hours. Under the conditions of the
investigation, reduction of toxicity of the poison was based on the
number of mouse units present per ml of test water. One mouse unit was
equal to Oel83 micrograms of poison.
-------
- Wi-
When the poison concentration was increased to 263 mouse units per
ml. (hi rag/1) the toxicity of the poison was not affected by 2 mg/1 of
chlorine dioxide.
When 2»0 mg/1 free available chlorine were added initially to 26
mouse units/ml (hoi mg/1) of the poison, there was no reduction of
the toxicity of the poison. Daring this examination, the free available
chlorine concentration decreased from 200 mg/1 to less than 0.05 mg/1
during the first 3^ minutes of exposure to the poison. At the end of two
hours, there were 1.5 mg/1 combined chlorine in the test water. Since it is
acknowledged that the poison constitutes some type of nitrogenous base, it
is most probable that the free available chlorine was instantaneously
changed in its chemical nature, when added to the poison.
During the utilization of chlorine dioxide, in the presence of U.7
mg/1 of poison, the concentration decreased from 1.9 mg/1 to 1.2U mg/1
during the first 3| minutes and to 0.73 mg/1 at the end of 2 hours.
SUMMARY
The shellfish poison in aqueous solution .was exposed to chlorine
dioxide and free available chlorine at pH 7»0 and stored at 25°C. for 2 hours.
Of the two disinfectants used, only chlorine dioxide inactivated the poison,
and this effect only occurred using a low concentration of the poison
(hoi mg/1). When the concentration of poison was increased to 1*7 mg/1,
2.0 mg/1 chlorine dioxide produced little or no inactivation. This work
must be looked upon as exploratory only and further investigations are
needed to define the usefulness of chlorine and chlorine dioxide in destroying
shellfish poison. The lack of an adequate supply of the poison made further
work impossibleo
-------
-U5-
ATFENDIX C
Activated Carbon Experiments
I. Dechlorination with Granular Activated Carbon Beds
by
F. M, Crompton, W. K8 Muschler, and R. L. Woodward
Five small filters were used to test the practicability of de-
chlorinating water with granular activated carbon. They were constructed
of lucite plastic columns 1 inch in diameter and 6 feet long, and were
filled with 30 inches of activated carbon. Four different carbons were
tested; one was used in two columns*
1. Cliffchar Carbon (granular)
2. Pitt Carbon (10 x 30 mesh)
3. Pitt Carbon (20 x UO mesh)
U. Hydrodarco Carbon (finer of the two grades available)
Water averaging about 20 ppm-free available chlorine was run through
the carbon filters at a rate equivalent to 3 gallons per square foot
per minute o The tests were started in September, 19!?6 and continued until
early January, 1957 or until a carbon column became clogged, whichever
came first,, When necessary the columns were backwashed using Cincinnati
tap watero
A summary of results are shown in the following table:
-------
TAHT.ff. I
Initial Vol. Final Vol.
(cu. inches) (cu. inches)
I 30 27.6
: 2 30 23.2
30 26.9
30 2U.9
30 25.9
Free Chlorine
Removed
(grams)
51.6
95.2
128.9
61.1
116,3
Free Chlorine
Removed per in-* Carbon
(grams)
1.87
U.12
U.78
2.U5
Iu50
Carbon
Hydrodarco Tube I
Hydrodarco Tube 2
Pitt 10 x 30
Pitt 20 x UO
Cliffchar
The dechlorinating ability of all of the carbons tested was judged
to be satisfactory for practical application in a carbon filter. On the
basis of results for Pitt 10 x 30 carbon, the most nearly depleted when the
test was stopped, it may be estimated that a filter bed 30 inches deep
will dechlorinate water having a 15 ppm free chlorine residual for at least
6 months. Sometime after this replacement will be necessary. When the
chlorine residual is less, the life of the carbon will be correspondingly
greater.
Over the range of flow and influent chlorine concentrations tested,
the filter effluent chlorine residual was approximately constant for each
type of carbon. The highest residual, in the range of 0.1 ppm was obtained
from Pitt 10 x 30 carbon. The effluent residuals for other carbons were less,
usually between 0.1 and O.Olj. ppm. Some effluent residual is desirable.
Head loss characteristics and clogging problems are of paramount
importance to practical operation of a carbon filter. These tests showed
that they are the most important criteria for selecting a suitable
granular carbon for dechlorination. A coarse carbon is recommended to mini-
mize head loss. A carbon should be dense, as well, since a dense carbon
-------
- U7-
permits more rapid backwash rates and results in better cleaning.
A good deal of trouble from "washing over" light carbons was
experienced in backwashing during the tests. This is demonstrated in Table I
by comparing the final carbon volumes to the initial volumes.
Pitt 10 x 30 was the most coarse and dense carbon tested. For
practical operation in a carbon filter, Pitt 10 x 30 would likely give
very satisfactory service.
During the last month of operation, samples were collected for
bacteriological examination from the three columns still in operation.
The samples were plated on Tryptose Glucose Extract agar and incubated
at 20* for periods up to 72 hours. The results showed that some bacteria
do grow in the carbon columns but a test for coliform bacteria was negative.
While these growths have no health significance they are troublesome and may
be responsible for clogging. Provision must be made to eliminate them
periodically, preferably by steaming the carbon bed.
-------
- U8-
APFENDIX C
Activated Carbon Experiments
II o Removal of Clostridivun botulinum Type A Toxin
from Water by Passage Through Activated Carbon
by
A. R. Brazis, Ae R. Bryant, P. Kabler, and R. L. Woodward
INTRODUCTION
The objectives of this exploratory investigation were as follows:
1. To determine if botulinum toxin is removed from water during
passage through the activated carbon column.
2. To obtain data on the efficiency of the carbon during long
and short periods of loading.
METHODOLOGY
The carbon used in this study was produced by the Pittsburgh Coke
and Chemical Company with the nomenclature: type "GW", 10 x 30 mesh.
The carbon was placed in a 25 ml burette thus making a filter
of the following characteristics:
Weight of carbon added 5.1810 grams
Volume of Carbon 11.0 ml
Diameter of column 0.971 cm.
Height of column 15.2 cm.
Area of column 0.7U cm2
Flow rate 9.03 mg/min or 11.1 min/100 ml
The carbon column was continuously dosed with the type A toxin
during two brief experiments.
-------
-U9 -
RESULTS
In experiment #1, a stock strength of the type "A" toxin containing
ii,500 mouse LD^QS per ml of solution was used. A total of 2,000 ml, at
pH 7cO and 25°C«, was applied to the column during a period of 3|? hours.
Samples were collected in 100 ml aliquots every eleven minutes. At the
end of approximately one hour of filtration, 90 to 98 percent of the toxin
was removed. See Figure 1, At the end of approximately three hours,
l£ percent of the toxin being dosed was passing through the filter unaffected.
During Experiment //2b, the same column which had been used in
Experiment ffl was utilized, after it had been backwashed with distilled
water. The type "A" toxin was applied at the same rate* During the first
eleven minutes of carbon passage, 71 percent of the toxin was removed.
However, during the next hour and three-quarters, 99 to 100 percent of the
toxin passed through.
DISCUSSION
It appeared that the removal of the toxin'by the carbon was ad-
sorptive in character. The efficiency of the carbon column during pro-
longed periods of dosing was low, following loss of its adsorptive
capacity during early periods of toxin dosing. No conclusions were
drawn conceniing the low capacity of the carbon column following early
removal of the type "A" toxin.
SUMMARY.
A small compact carbon column has been used to remove Clostridium
botulinum type "A" toxin (crystalline) in water. Dosing periods ranged
from 2 to k hours. Using activated carbon, the toxin was removed, appar-
-------
100
Experiment II Concentration of toxin i
feed iolution w» 4.500 LDgo per ml
I
t
o
1
8
I
. Experiment IZb Concentration •
of toxin in feed wa»
S.SOO LDso/ml
eio
240
_i_
2TO
10
60
120
BO
Doling Time in Minute*
180
REMOVAL OF CLOSTRIDIUM BOTDLPTOM TYPE "A" TOXIN FROM
WATER BY FILTRATION THROUCH PITTSBURGH CARBON TYPE "CW"
10 X 30 MESH
Figure 1
-------
- 51-
ently by adsorption, by 90 to 98 percent during the first hour of treat-
i
mentc Continued dosing appeared to reduce the efficiency to 1*2 percent
at the end of three hours. Backwashing of the carbon did not appear to
increase, significantly, the efficiency of the carbon. Further loading of
the column produced 99 to 100 percent persistence of the toxin within 30
minutes following backwashing.
The carbon column appeared to reach its adsorptive capacity within
a short period of time. It seemed likely that further studies using
greater depths of activated carbon, different types of carbon, and lower
concentrations of toxin may be necessary to judge the effectiveness of
the carbon column with regard to removal of bacterial toxins.
-------
-52 -
APPENDIX C
Activated Carbon Experiments
III. Use of Carbon for Removal of GB From Water
by
Jesse M. Cohen and F. M. Crompton
INTRODUCTION
Active carbon has been recommended by several investigators for
removal of toxic war gases from water. Data are available in the literature
on the capacity of various carbons for removing the organic phosphate
class of war gases , called "nerve" gas, from water. These reports con-
cluded that several carbons were effective adsorbents, In reasonable con-
centrations, for removing toxic concentrations of G8 from water. Since
previous work covered only batch treatment of water by carbons in powdered
form and, since the carbons tested did not include the carbons under con-
sideration for chlorine removal, it was necessary for this laboratory to
obtain additional information.
The objectives of this brief study were to:
1. Obtain data for the construction of an adsorption isotherm
to enable a comparison of the carbon under study with
carbons previously investigated.
2. Determine whether removal of GB from water is feasible
by a column process in contrast to the previously re-
ported batch operation.
EXPERIMENTAL
BATCH TREATMENT
Batch treatment of water contaminated with GB with varying amounts
of carbon was performed in the usual manner for determining adsorption
-------
-53-
isotherms for carbon. Some of the conditions of the test were based on
previous experience in the literature. Other conditions were arbitrary
or dictated by tiie use of the carbon in practice.
Seven 200 ml portions of distilled water, buffered at pH 6.0 and
containing about $0 ppm of GB, were treated with varying amounts of
carbon. The solutions containing suspended carbon were agitated with an
efficient wrist-action shaker for five minutes. The usual stirrer type of
mixing could not be used in these experiments because the granular form
and high density of the carbon prevented dispersion of the suspension.
The method used provided a satisfactory dispersion. At the end of the
shaking period, suspended carbon was removed by filtration through medium
porosity fritted glass filters. Analyses for GB remaining in the filtrate
were performed immediately by the peroxide procedure which is specific
for GB0 Buffered water at pH 6.0 was chosen to minimize hydrolysis of
GB. A five-minute contact time was chosen since this corresponded ap-
proximately to the detention time in a column operation with a loading
of 3 Gal/ft /min. The data obtained in this experiment are shown in
Table I. Also shown are the data for construction of the adsorption
isotherm for this test. The latter data were computed according to the
empirical adsorption equation of Freundlich and are plotted on double
logarithmic paper in Figure 1. The equation for the straight portion of
the line is calculated to be:
|=3.13C°'558
-------
- 5U-
TABLE I
REMOVAL OF GB FROM WATER BY
CARBON TYPE "GW" 10 x 30
" Carbon
added in
grams
0.0
2.03
U.17
6.11
10.0
18.3
22.1
26.2
Solution
in
ml
200
200
200
200
200
200
200
200
GB in
Before
"V
1*6.5
U6.5
U6.5
U6.5
U6.5
U6.5
U6.5
U6.5
mg/liter
After
"C"
—
23.5
7.7
3.6
2.0
0.76
O.U8
0.11
PITTSBURGH
MESH
Removed
X(Co-C)
—
23.0
38.8
U2.9
UU.5
U5.7U
U6.02
U6.39
X
M
11.3
9.30
7.02
U.U5
2.50
2.08
1.77
Percent
GB
Removed
U9.5
83.5
92.3
95.7
98.it
99-0
99.9
-------
-55-
Conditions
100
•a
u
a
o
XiS
10
I 1 I ! I I I 11
I I I I I I I-
pH = 6 0 o
Temp = 23° - 25
Water = Buffered distilled water
Contact time = 5 minutes
Original GB concentration • 46.5 mg/liter
£=3.1300.558
I.
0.1
1.0 10
mg/liter GB remaining
REMOVAL OF G.B. FROM WATER
BY PITTSBURGH CARBON TYPE "GW"
10 x 30 MESH
J L_L
100
Figure 1
-------
- 56-
Two points not on this line can be ascribed to analytical diffi-
culties in determining accurately small amounts of G8.
The data show that the carbon under test does not compare favorably
with carbons reported in the literature«, This, however, may merely reflect
the fact that this carbon is a granular material and hence not as efficient
an adsorber in batch treatment as the powdered carbons reported in the
literature.
COLUMN TREATMENT
Determination of the capacity of this carbon to remove GB from water
solution on a continuous flow basis was made in the following manner.
A carbon filter was constructed with the following specifications:
Diameter 2.9U cm
Height of carbon column 31.U cm
Weight of air-dry carbon 105. grms.
By backwashing with distilled water, carbon fines and soluble alkaline
salts were first removed. A feed solution, 9955 ml, containing £7 mg/1
of GB in distilled water, buffered at pH 6.0, was fed to the column at an
average rate of 62.1 ml/min, which is equivalent to 2.25 gal/ft /min.
Samples of the effluent were collected in separate aliquots, ranging from
100 to 500 ml, over the entire period of the run. Determinations for GB
in the effluent were made within 2 hours of sample collection.
No GB was detected in any of the filtrate samples, which leads to
the conclusion that a minimum of 56? mg of GB put on the filter was re-
moved by 105 gram of carbon or at least 5«U mg of GB/gram of carbon.
-------
- 57-
Because of the limited supply of GB, the large column was abandoned
and a smaller filter was operated to determine the capacity of this carbon
for GB removal.
A carbon filter was prepared in a 25 ml burette with the following
specifications:
Diameter 0.971 cm.
Height of carbon column 15.2 cm.
Weight of air dry carbon 5.21 grm.
Operation of this column was similar to the larger filter. A feed
solution containing 116 ppm of GB was fed to the filter at an average
r\
ra'te of 9.06 mg/min, which is equivalent to 2.33 gal/ft /min. Samples of
the effluent were collected in separate aliquots, ranging from 50 to 100
ml, over the entire period of the run. In contrast to the previous filter,
increasing concentrations of GB appeared in the filtrate. Operation of
the filter was stopped at the end of the day's run after 3,200 ml had been
collected. Filtration was resumed the following day and an additional
1,600 ml were collected. On standing overnight the concentration of GB in
the feed solution dropped from 116 to 75 ppm. This information is shown
in Figure 2.
It is evident from these curves that the capacity of the carbon
column was exceeded very early in the operation, and increasing concentra-
tions of GB were obtained in the effluent. No conclusions on the capacity
of this carbon to remove GB can be made from this experiment. Comparison
of the data on the two columns suggest that the depth of the carbon column
has a profound influence on the capacity to remove GB.
-------
60
50
3 40
0)
e
n
o
Concentration of GB in Feed .
Solution = 116 ing/1
Concentration of GB in Feed
Solution = 75 mg/ 1
30
BO
E
10
I
ml of GB solution filtered
I
I
I
I
I
0
0
500
1,000
1,500
I
2,000
2,500
3,000
3,500
4,000
4,500
5,000
580
58
116
174 232 290 348
mg of GB put on filter
406
464
522
REMOVAL OF GB FROM WATER BY
FILTRATION THROUGH PITTSBURGH CARBON
TYPE "GW" 10 x 30 MESH
Figure 2
-------
- 59 -
The curve showing data obtained after resting the column overnight
indicates that adsorption may not be the entire mechanism for GB removal.
The greatly lowered initial concentrations of GB in the effluent would
suggest that the carbon catalytically increased the rate of GB hydrolysis.
Further evidence in support of this hypothesis is the fact that increasing
amounts of fluoride were detected in the effluents from the larger column,
as follows:
Determination of Fluoride in Filtrate
Aliquot at indicated
vol. of solution filtered
200 ml
5000 ml
9500 ml
mg/liter Fluoride
in filtrate
1.2
1.6
2.U
Percent GB
Hydrolyzed
16
21
31
SUMHftHI
1. Data was obtained for the construction of an adsorption isotherm
for carbon removal of GB from water.
2. One column experiment operated on a continuous flow basis
showed that a minimum of 5«Umg GB/grm carbon could be removed
from solution on a column 31«U cm in depth.
3. Capacity of a second, smaller column, 15.2 cm in depth, was
exceeded very early in the experiment and increasing concen-
trations of GB were obtained in the filtrate.
U. Mechanism of GB removal may include catalytic hydrolysis in
addition to adsorption.
5. Removal of GB from water by a column operation was more ef-
fective than would have been predicted from the adsorption isotherm
data.
-------
_ 6o-
APPENDIX D
Design of Gravel Filled Chlorine Contact Tank
F. M. Crompton, W. K0 Muschler and R0 L. Woodward
INTRODUCTION
The purpose of a chlorine contact tank is to retain chlorinated
water for a time sufficient to insure destruction of any microorganisms
present before the water reaches a point of use. The tests reported
here show that a tank filled with a granular media, pea gravel in this
case, is a practical way to provide chlorine contact.
A chlorine contact tank should have the following characteristics:
1. It should minimize short-circuiting of the flow.
2. It should have stable flow pattern over the range of expected
flows and temperature fluctuations.
3. It should be ^economical to construct and maintain.
In these investigations the retention characteristics of tanks
were determined by injecting a dye tracer into the influent water and
detecting the dye in the effluent from the tank. For approximate com-
parisons of various arrangements, the time of appearance of the first
trace of dye was used,, For more thorough studies complete curves of
dye concentration as a function of time were defined. The ratio of
first trace time to the theoretical displacement time of the tank gives
a measure of the effectiveness of the tank as a chlorine contact chamber.
Before considering flow through granular media as a method of
chlorine contact, flow through unbaffled cylindrical tanks was investi-
gated because of the obvious simplicity and low cost of such tanks .
-------
- 61-
Both horizontal and vertical flow arrangements were studied, bat in all
such tanks, poor results were obtained* Short circuiting was pronounced
and the flow patterns were markedly unstable. Variations in rate of
flow and minor temperature changes in the water caused major changes
in the retention characteristics of such tanks even though great care
was taken in design of the inlet to obtain even distribution across
the section of the tank. In the tanks studied, the ratio of first
trace time to theoretical flow-through time was highly variable and
generally less than 0.2.
One vertical baffling arrangement studied was found to have a
first trace time consistently greater than O.U of the average flow-
through time, and a stable flow pattern as well. This arrangement
consists of concentric cylinders, each with one open end, placed
vertically with the open ends alternately at the top and bottom of
the tank. The flow path begins at the outside and converges inward
through the over-and-under arrangement. 'While the performance of a
model of this type tank is excellent, construction costs would be
relatively high.
The device recommended here consists of a vertical-flow, tank
filled with pea gravel. Horizontal flow is not practical for obvious
reasons. A gravel-filled tank has an advantage of being simple and
economical to construct.
TEST SET-UP
To test the flow-through characteristics of a -tank filled with a
granular media, two experimental set-ups were devised.
Preliminary tests were conducted using a 55-gallon steel drum,
-------
- 62-
shoun in Figure 1, filled with pea gravel, effective size =0.13 inch
and uniformity coefficient = 1.75* Two flow rates were used, 0.25
and 0.75 gpm; the resulting mean velocities through the voids were
0.0021 and 0.0063 ft/sec, respectively.
Results using the 55-gallon steel drum showed that the method held
promise and a full depth set-up should be tested. Figure 2 shows the cy-
lindrical tank assembled for this purpose. The tank was filled with 15
feet of pea gravel, having an effective size of 0.137 inch and a uniformity
coefficient of 1.97* The gravel was supported by five grates as shown in
the figure. For an inlet distribution system, a h-inch clear space was
provided below the gravel fill. Metered flow was piped into opposite sides
of this space. The outlet arrangement was the same as the inlet distribu-
tion system. The large scale set-up was tested at three flow rates$ namely,
2*65, 10.6, and 30 gpm. These resulted in mean velocities through the
voids of 0.0021, 0.0082, and 0.023 ft/sec, respectively.
Fluorescein dye was used as the flow tracer. A concentrated solution
(586.5 mg/ml) was injected into the flow, using a hypodermic needle and a
syringe just after passing the metering device.
In both test set-ups, the flow was sampled at intervals from a tee
in the effluent line. The optical density of the sample was determined
on a Model 20, Bausch and Lomb Colorimeter, using a wave length of U?5 m^i.
HESOLIS
Figures 3 and 1; show the flow-through curves obtained in the
55- gallon steel drums at the two flow rates tested. Figures 5» 6, and 7
show the flow-through curves obtained at different flow rates in the
15-foot gravel filled tank.
-------
-63-
To Dischorge
55-qal Steel Drum-
Filled with Pea Gravel
Rotameter
Clear Plastic Hose
55-GALLON CHLORINE CONTACT TANK
Figure I
-------
-6U-
To Discharge
From Supply.
Grates
Rotameter
• 3'-cr-
Old.
T*eo Gravel^
throughout Tan
To Sample
4'-0"
2--OT1
3'-0"
2'-0"
15-Foot CHLORINE CONTACT TANK
Figure 2
-------
Jan. 30, 1957
99.75% of dye recovered
Jan.Z8, 1957
1 10 .91% of dye recovered
C = Concentration at time T
C = Average concentration
T = Actual time at concentration (C)
T = Theoretical time
o
0.2
2.O
FLOW THROUGH CURVE
55-GALLON TANK AT 0.25 GPM
Figure 3
-------
Jan. 29, 1957
1 19 .38% of dye recovered
Feb. 7, 1957
102 .89% of dye recovered
= Concentration at time T
C = Average concentration
= Actual time at concentration(C)
T = Theoretical time
o
Feb. 6, 1957
105.79% of dye recovered
Jan. 25, 1957
86.68% of dye recovered
0.2
0.4
0.6
0.8
1.0
1.2
1.4
FLOW THROUGH CURVE
55-gallon tank at 0. 75 G. P. M.
FIGURE 4
T
Tr
1.6
1.8
2.0
-------
c
c.
April 18, 1957
93.47% of dye recovered
April 22, 1957
97 .31% of dye
recove red
C = Concentration at time T
C = Average concentration
T = Actual time at concentration (C)
= Theoretical time
-April 23, 1957
J 86.24% of dye recovered
0.2
0.3
1.10
FLOW THROUGH CURVE
15-FOOT TANK AT 2.65 GPM
Figure 5
-------
April 11, 1957
91.7% of dye recovered
C
C
April 9, 1957
95% of dye recovered
CODE
C = Concentration at time T
C = Average concentration
T - Actual time at concentration (C)
T = Theoretical time
0.2
0.3
0.4
0.5 0.6
T
T
0.7
0.8
0.9
1.0
FLOW THROUGH CURVE
15-FOOT TANK AT 10.6 GPM
Figure 6
-------
c
c
April 26, 1957
85% of dye recovered
April 25. 1957
8920% of dye recovered
CODE
C = Concentration at time T
C = Average Concentration
T = Actual time of concentration (C)
T = Theoretical time
o
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
FLOW THROUGH CURVE
15-FOOT TANK AT 30 GPM
Figure 7
-------
- 70-
The ordinates of the flow-through curves have been obtained by
dividing each observed dye concentration (C) by the concentration (C0)
that would have been obtained if the dye used had been evenly dispersed
in the gross tank volume (volume without gravel fill). The abscissa
were obtained by dividing the time (T) of an observed concentration by
a theoretical flow-through time (T0) calculated by dividing the gross tank
volume by the rate of flow. In this manner, a dimensionless plot is ob-
tained •
The flow-through curves demonstrate that the flow pattern was ex-
tremely stable. Temperature differences of J?°C in the incoming water did
not upset the flow pattern in the 5>J>-gallon steel drum.
DISCUSSION OF RESULTS
(1)
Beran has shown that the following equation describes the dispersion
of a slug of material in passing through a granular bed, provided the flow
is rapid enough to neglect diffusion.
W (?
C = —. ^^rnarr* 6 l\
where: C = Concentration of tracer observed at x and T.
W = Mass of tracer introduced at x » 0 and T = 0.
A = Cross sectional area of bed.
T = Time of observation of C at x.
x = Distance along tank to point of observation of C
v = Mean velocity through the voids „
K = Dispersion parameter. This is a function of
velocity and grain size and is equal to K'vd, where
d is a measure of grain size, taken here as equal to
the effective size, and K' is a dimensionless constant,
dependent only on shape and packing.
-------
- 71 -
For the equation to be useful as a rational basis for designing a
chlorine contact tank, the constant X1 must be evaluated. This can be done
by plotting the flow-through data obtained from the experimental tanks on
arithmetic probability paper and picking off the standard deviation corres-
ponding to the first portion of the flow tracer. (See Figures 8 through 20)
The standard deviation (OQ) of the dimensionless plots in the Appendix is
related to K1 as follows:
By definition the standard deviation of equation (1) is:
<5* = (2KT)a B (2K«vdT)* (2)
where o^ = The standard deviation with length units.
Rearranging:
(3)
•2VdI
The following relationships are noted:
T - AL
To - 3—
v = TT
where: 6"t = the standard deviation with units of time.
o~0 = the standard deviation of the dimensionless plot
A = cross sectional area of the tank
L = length of the tankj
Q = discharge
f = void ratio of the gravel
Substituting the above relationships:
K1 - °Q2TQV = ^o2 AL Q
2 M 2 F" . Q Af
-------
- 72 -
o.oi
PROBABILITY PLOT FOR FLOW THROUGH A
15-FOOT TANK, Q = 2 .65 GPM. V = O.OOE06 FPS
APRIL 18. 1957
Figure 8
-------
- 73 -
0.01
0.05
•O.I
0.2
0.5
5
10
20
«, 30
c
S 40
a
& 50
*J
8 60
h
S,
80
90
95
98
99
99.8
99.9
-------
0.01
0.05
O.I
0.2
0.5
I
2
5
10
20
oo 30
3 40
Ss
8 60
h
(X 70
80
90
95
98
99
99.8
99.9
99.99
CT=0.025
(T= 0.026
0.2
0.3
0.4
T
T.
0.5
0.6
PROBABILITY PLOT FOR FLOW THlTOUGH A
15-FOOT TANK. Q .= 2.65 GPM, V = 0.00206 FPS
APRIL Z3, 1957-
Figure 10
-------
-75-
0.01
0.05 -
O.I -
0.2 -
5
10
20
30
S 60
n 70
80
90
95
98
99
99.8
99.9
99.99L-
0.2
0- = 0.030
0-= 0.029
0.3
0.4
I
T
0-5
0.6
PROBABILITY PLOT FOR FLOW THROUGH A
15-FOOT TANK, Q = 10.6 GPM, V = 0.00825 FPS
APRIL 9. 1957
Figure 11
-------
-76-
0.01
0.05
O.I
0.2
0.5
I
2
5
10
20
30
50
2 60
S. 70
80
90
95
98
99
99.8
99.9
99.991-
0.2
(T= 0.027
M = 0.377
cr=0.028
0.3
0.4
0.5
0.6
T
T
PROBABILITY PLOT FOR FLOW THROUGH A
15-FOOT TANK, Q = 10.6 CPM, V = 0.00825 FPS
APRIL 11, 1957
FIGURE 12
-------
- 77 -
0.01
).05\
O.I
0.2
0.5
I
2
5
10
20
c 30
• H
S 40
flj
ft
*. 50
8 60
u
0. 70
80
90
95
96
99
99.8
99.9
99.99
0.3
0.029
M = 0.385
-------
- 78 -
o.oi
99.99
0.3
0.4
0.5
0.6
0.7
PROBABILITY PLOT FOR FLOW THROUGH A 15-FOOT TANK,
Q = 30 GPM, V = 0. 0233 FPS
April 26, 1957
Figure 14
-------
- 79 -
0.01
0.05
0.
0.2
O.S
2
5
10
20
oo 30
•r4
% 40
S 60
0. 70
60
90
95
98
99
99.8
99.9
99.99
0- = 0.026
M= 0.345
0-=0.025
0.2
0.3
0.4
T
T
0.5
0.6
PROBABILITY PLOT FOR FLOW THROUGH A
55-GALLON STEEL DRUM, Q =0.75 GPM. V = 0 00633 FPS
JANUARY 25. 1957
Figure 15
-------
- 80 -
0.01
0.05
O.I
0.2
0.5
5
10
20
BO 30
S 40
S 60
0. 70
80
90
95
98
99
99.8
99.9
99.99
0.2
CT= 0.037
M= 0.397
-------
0 01
- 81 -
0 05
O.I
0 2
0 5
I
2
5
10
20
ea 30
r
: 40
ifl
* 50
8 60
M
(X 70
80
90
95
cr=0033
0- = 0.032
98
99
99 8
99 9
99.99
0.2
03
0.4
T
T
0.5
0.6
PROBABILITY PLOT FOR FLOW THROUGH A
55-GALLON STEEL DRUM, Q = 0 75 GPM, V = 0.00633 FPS
FEBRUARY 6, 1957
Figure 17
-------
- 82 -
U.UI
0.05
O.I
0.2
0.5
1
2
5
10
20
DO 30
.3
£ 40
rt
5 50
fl
o 60
Q)
ft 70
80
90
95
98
99
99.8
99.9
QQ QQ
'\ 1 ' 1 ' 1
- \
•~ •
- \
\
V
^^
- 26 \ .
a"l<026~^>\ .
•
\ \
\ '••
M=0.35I-TJ-
\
: \
0^=0.026-^ ^.
-
—
—
__
••
i
i
—
^
—
^""
-
™*
—
_
—
:
—
• ~
•
—
—
—
^™
—
—
'
0.2 0.3 0.4 - 0.5 0.6
T
T^
PROBABILITY PLOT FOR FLOW THROUGH A
55-GALLON STEEL DRUM. Q = 0.75 GPM, V = 0.00633 FPS
FEBRUARY 7, 1957
Figure 18
-------
- 83 -
0.01
0.05
O.I
0.2
0.5
I
2
5
10
20
BO 30
» 40
OB
It
fc 50
£ 60
u
fc 70
80
90
95
98
99
99.8
99.9
99.99
0.2
0.9
0.4
T
T
0.5
0.6
PROBABILITY PLOT FOR FLOW THROUGH A
55-GALLON STEEL DRUM, Q = 0.25 GPM, V = 0.00211 FPS
JANUARY 28, 1957
FIGURE 19
-------
- 8U -
0.01
a 40
a
50
S 60
h
£ 70
99.8
99.9
99.99
\
0.05
O.I
0.2
0.5
I
2
5
10
20
g.30
* x V
\
\\
. \ \
-\
\
M= 0.331
80
• = 0.024
90
95
98
99
\
\
0.2 0.3 0.4 0.5 0.6
PROBABILITY PLOT FOR FLOW THROUGH A
55-GALLON STEEL DRUM. Q = 0.25 GPM, V = 0.00211 FPS
JANUARY 30, 1957
Figure 20
-------
2fd
For any particular tank, the quantity ( - ^ . ) is constant. For
2 fd
each experimental run a straight line has "been drawn on an arithmetic
probability plot connecting the first several points, corresponding to the
initial trace. These first points were used since the purpose of this
analysis is to predict rationally the first trace .time. The value of K1
was calculated from the mean( — 4— )and standard deviation (<£-) obtained from
•"•o
this straight line. The values of K' obtained from both the 15-foot tank
and the 55-gallon steel drum are plotted on Figure ZL» versus tiie mean void
velocity. The information is also given in Table I. The plot shows that
a K1 value greater than U would be a safe value for design purposes, pro-
vided the mean void velocity is greater than 0.006 ft/sec, and the granular
media used is similar to the pea gravel in these tests.
If equation (l) were followed perfectly, the data would plot as a
straight line on arithmetic probability paper. The fact that it does not
indicates the extent of inlet and outlet interference in the tanks; even
so, the results show that Beran's equation characterizes the flow pattern
satisfactorily for practical purposes. Since Beran's equation was found
to characterize the flow, it is possible to predict the behavior and flow
pattern for other installations „
-------
K'
10--
8-
6--
0
steel drum
O
15-foot tank
J L
_L
_L
0 .002 .004 .006 .008 0.01 0.02
Mean Void Velocity (ft/sec)
VALUES OF K1 CORRESPONDING TO INITIAL TRACE
Figure 21
0.03
-------
- 87 -
TABLE I
VALUES OF K' CORRESPONDING TO INITIAL DIE TRACE
Date of
Run
Mean
Void Velocity
!L
(T~ nT~
0 io
L
2 f d
K«
15-foot tank:
U/18/57
U/22
U/23
U/9
U/n
U/25
U/26
55-gallon
1/25/57
1/29
2/6
2/7
1/28
1/30
0
0
0
.00206 ft/sec.
.00206
.00206
0.00825
0
.00825
0.0233
0
.0233
0
0
0
0
0
0
0
.052
.037
.026
.030
.028
.028
.029
0
0
0
0
0
0
0
.U7
.U25
.U70
.390
.377
.385
.389
1625
1625
1625
1625
1625
1625
1625
9
5
2
3
3
3
3
.3U
.2U
.97
.75
.38
.31
.51
steel drum
0
0
0
0
0
0
.00633 ft/sec.
.00633
.00633
.00633
.00211
.00211
0
0
0
0
0
0
.026
.038
.032
.026
.031
.02U
0
0
0
0
0
0
.3U5
.397
.393
.351
.379
.331
3U1
3U1
3Ui
3U1
3U1
3Ul
0
1
0
0
0
0
.668
.2U
.888
.657
.865
.59U
-------
CONCLUSIONS
10 Low velocity flow through unbaffled cylindrical tanks is not
sufficiently stable to recommend their use as chlorine contact tanks.
2. Flow through pea gravel is a practical method of providing time
for chlorine contact without appreciable short-circuiting.
3. The equation of Beran has been shown to describe reasonably well
the longitudinal dispersion of flow through pea gravel, and the
equation is suitable as a basis for design.
k. The dispersion parameter K1 has been evaluated for the "first
trace" flow through pea gravel. For design purposes a value
greater than li appears safe, provided the mean void velocity is
greater than 0.006 ft/sec.
DESIGN OF A CHLORINE CONTACT TANK
Equation (1), describing the flow dispersion through granular
media, is taken as the basis of design. The time (tc) when the "first
trace" arrives at the outlet is defined, arbitrarily but conservatively,
as that time when 3 x 10~' of the total tracer has passed the tank outlet.
If equation (l) were a normal probability curve in time this would occur
five standard deviations (SO ahead of the mean. Even though equation (1)
is not quite normal in time, it is near enough so that the following re-
lationship may be taken as correct for design purposes.
L - vtc = 5
-------
- 89 -
Rearranging and taking -=- = To, the theoretical detention times
v
T0
+ 25 K'd i/(2 + (25 K'd } ( 25 K'd/
L / L L
This equation, the porosity of a gravel (f), and the following
relationship are all that is required for designj
v _ _ £_ L
" T ~
DESIGN EXAMPLE
Problem: Calculate the inside dimensions of a gravel filled
chlorine contact tank for 5-minute and 15-minute
detention.
Given: Average Flow Rate = 100,000 gpd
Maximum Flow Rate = 300,000 gpd
K' = 5
Effective size of pea gravel (d) = 0013 inches
Porosity (f) = 0.35
Assume height of tank L = 15 ft.
Solution: To solve for the dimensions of the tank the height L
must be assumed and A, cross section area, calculated.
If these are not satisfactory another L may be assumed
and the calculations repeated.
tc
TO
i + 25 K'd */n
1 L -/U
/0.13 ^
i - 25(5/ 12 }
15
, ^ 25 K'd)
L
4.
(2$ K'dx
( L }
25(5)
15
(0.13 ) ,0.13'
12 \ /25(5) ^ 12 '
15
= 1 + .0903 - y(2.0903)(0.0903) = 1.0903 * O.U35
Use minus sign since plus sign corresponds to 5
-------
- 90 -
c n ^r- (First trace efficiency)
For tank with 5 minute detention tr = 300 sec.
v =
0.655 ^ **• = 0.05 ft/sec.
300 sec*
-°167 ft/SeC'
51" Detention
Area of tank (1)5 = -i_ = g^Vo^ = ^ Sq'ft'
Concrete tank dimensions /26.U = 5.1U ft.
Inside dimensions 5' - 2" x 5' - 2" x I?1 - 0"
(Allowance of 21 was made in the tank height for flow distribution
and collection systems)
Steel tank diameter D = A^A = /JL(26.1i) = 5.88'
yfi y "^
If the direction of flow in the chlorine contact tank is chosen
upward, the distribution system will be located on the tank bottom. One
satisfactory distribution system may be constructed by using
perforated pipes, as in a sand filter underdrain, with the perforations
in a horizontal plane. The holes should be small enough to insure good
distribution by providing a sufficiently large, controlling head loss.
The pipes can rest on the tank bottom and be connected through suitable
laterals and headers to the inlet pipe, probably most conveniently located
on the side of the tank. Coarse gravel should surround and cover the dis-
tribution system to about a foot.
Other standard type filter underdrain systems should serve equally
well.
-------
- 91-
The collecting system may be ccns true ted in a manner similar to
the distribution system. While there have been no experimental tests
on the distribution system recommended above, it is not believed they
are needed. Access ports in the cover should be provided. Figure 22
shows a sketch of a typical chlorine contact tarik constructed of
reinforced concrete.
-------
Flow
Coarse Gravel
Inlet
Built of reinforced
concrete walls
12" thick
Typical Chlorine Contact Tonk
Figure 2t
-------
- 93 -
REFERENCE
1. Beran, Mark Jay. Thesis to the Division of Applied Science for the
Degree of Doctor of Philosophy in the Subject of Engineering,
Harvard University, Cambridge, Mass., May, 1955-
-------
- 9h -
APPENDIX E
Estimated Costs for Re-treating Water
To Protect Against Spores, Vegetative Bacteria or Toxin
INTRODUCTION
Cost estimates were made for re-treating finished water using a
long length of pipe or a gravel-filled tank as the basic detention unit
to assure proper chlorination0 It was determined that a concrete tank
would be less expensive and yet as efficient. Buildings, pipe, valves,
fittings, feeders, filters, indicators, etc., will cost about the same
for either type of detention unit so these costs have been listed in
this appendix along with the costs for a tanke Tank length to width
ratios were selected so as to be similar to those in the experiments
performed at this Center, and 15-feet was considered a minimum depth.
Only prices of water treatment equipment commercially available
have been used, and these items have been amortized over a 10-year per-
iod at 2.5 percent interest. Totals include cost of Installation and
maximum daily chemical use as well as all piping and equipment.
Costs have been estimated for two types of plants:
1. High chlorine residual plant with a 60-minute detention
to protect against spores for average continuous flows of
2^,000, 100,000, 500,000 or 1,000,000 gpd, with the maximum
flow being considered to be 3 times the average.
2. Low chlorine residual plant with a 5-minute detention to
protect against vegetative bacteria or toxin for continuous
flows of 25,000, 100,000, 500,000 or 1,000,000 gpd. A
basic flow diagram is shown on the next page.
-------
-95-
Drain Valve
1
i
\
\
Re
Wo
Normal finished
water line
Valve
± S~*\ *
* (J
Flow
Meter
11. Bypass _
rr valve
|M
L| Valve
J (Optional, Acid Feed) |
1
K|
pH Indicator.
Recorder and Alarm
Chlorine Indicator,
Recorder and Alarm
Detention
Unit:
Pressure tank
filled with gravel
5 or 60-minute
detention
/Pres
( Car
\Fllt
;
^•^
treated
ter
sure\
ban I
ers 7
J (Optional, Soda Ash Feed)]
Valve
[-)- Valve
BASIC FLOW DIAGRAM OF RE-TREATMENT PLANT
-------
-96-
In addition, equipment costs and daily operating costs have been
computed for modifying conventional treatment plants in the 0,5 to 10
MOD range.
SUMMARY OF
PLANT AND OPERATING COSTS
Cost for Protection Against Spores by Re-treatment:
For Average Continuous Flow oft
GPD
2$,000
100,000
500,000
1,000,000
Cost for Protection Against Spores
Conventional Treatment Plant:
Cost of Unit
with Tank
$ 37,000
59,000
157,000
27U,000
in Raw Water by
Daily
Operating
Cost
$ 20.78
it2.ua
mo. 90
269 .Uo
Modifying
For Average Flow of: Total Cost Daily
Operating Cost
MOD
0.5
1
5
10
ft U*,i5o
16,060
20,900
28,600
$ 22.20
37.10
120.00
216.00
-------
- 97 -
SUMMARY OF
PLANT AND OPERATING COSTS
(Cont'd.)
Cost for Protection Against Vegetative Bacteria or Toxin by Re-treatment;
For Average Continuous
(with carbon filters)
(without » » )
1,
Flow of:
GPP
25,000
100,000
100,000
500,000
000,000
Total Cost of
Unit with Tank
$ 17,600
30,000
111, 000
80,000
135,200
Daily
Operating Cost
$ 9.37
16.61
8.81
52 .U5
89.57
-------
- 98 -
EXAMPLE OF THE METHOD
FOR DETERMINING TANK SIZE AMD COST
Basis of Design (see Appendix D)
Detention time: — 1 hour
Average flow: ----- 0.025 mgd
Maximum flow: ----- 0.075 mgd = 0.116 cfs
Use; 15' deep tank
K1 = (Dispersion parameter) = over U, so use 5
d = E.S. = Effective size of pea gravel = 0.13" = 0.13
-^2
U.C. = uniformity coefficient of gravel = 1.75
f = porosity = 0.35
Solution . To determine dimensions of the tank, the height, L, must
be assumed and the cross-sectional area, A, calculated. If
these are not satisfactory, another L may be assumed and Hie
calculations repeated.
1. Determine the first trace efficiency, tc
tc = 1 + 25 K'd + / (2 * 25K'd)(25K'd)
T L "V ~T~~ ~T~~
0
1 * -- + /( 2. 0902) (0.0903) = 1.0903 ± o.J;35
= 1.0903 - O.U35 = 0.655 for first trace
Velocity = tc L =0.655 * 15 = 0.0027U
~ tc" 5350
A = discharge in cfs _ 0.116 0 ^ _ 1?0 ft
velocity x porosity " 0.00271 *35 " Q' '
Select cross section of II1 x 11'
-------
- 99 -
Volume of concrete necessary;
Assume 1-foot thick walls and an extra foot on each end of tank for
distribution and collection system so inside dimensions are 11' x
11' x 17'.
2 sidewalls then are: 17 x 11 x 2 = 37U
2 end walls: 17 x 13 x 2 = Wi2
Top & bottom: 13 x 13 x 2 = 338
Total • 115U cu.ft.
U2.7 cu.yds.
Use: U3
Cost Estimate;
Concrete at $80/cu.yd. = hi x 80 = $ 3,U50
Excavation at $6/cu.yd. = 11 x 11 x 20 x 6 -, _
27 =
Gravel at fth/cu.yd. = 11 x 11 x 17 x U _ ,00
27
Under drain system 800
Piping 800
5,890
10% Installation, etc. 589
$ 6,U79
Use: 6,500
All other tank sizes and costs were determined in a similar manner.
-------
- 100 -
SUMMARY OF TOTAL COSTS OF CONSTRUCTION
FOR CONCRETE, GRAVEL-FILLED HOLDING TANK
Flow, GFD 5-Minute Period 60-Minute Period
Avg. Max.
25,000
100,000
500,000
1,000,000
75,000
300,000
1,500,000
3,000,000
1,900
3,200
8,500
Ul,000
6,500
13,500
58,000
100,000
-------
- 101 -
COST ESTIMATE TOR A
25,000 gpd, CONTINUOUS-FLOW, RE-TREATMENT SYSTEM WITH
LOW CHLORINE RESIDUAL FOR PROTECTION AGAINST
VEGETATIVE BACTERIA AND TOXIN
Item Description Cost
1 Building to house system built of cement block, flat roof, $ 3,500
no architectural treatment, built by private contractor.
2 U" Bypass Valve 125# Iron Body Wedge, Gate Valves, $20 each. UO
3 2" Bypass Drain Valve 125# Iron Body, Wedge Gate Valve 15
U U" Bypass pipe and fittings l6l
5 3" Treatment Entrance Valve 125# Iron Body Wedge Gate Valve 20
6 Flow meter and Transmitter 300
7 Residual Chlorine Recorder 3*000
8 pH indicating and Recording Instrument 1,200
Chlorine Feed Pump 653
2 Chlorine Solution Tanks $300 each (approx. 135 gal.ea.) 600
9 Temperature Indicator and Recorder. 280
10 3" Cast Iron Flanged pipe and fittings - Treatment line within 170
building.
11 Chlorine Contact tank, concrete, U1 x h* x 17', 5-minute 1,900
detention period—complete with gravel, excavation, laying
and backfilling.
12 1 Pressure Filter with appurtenant equipment 1*900
13 3" Bypass Valves for cleaning, flushing, adjusting system U5
lU Miscellaneous pipe and fittings 150
$ 13,93U
for furnishing and maintenance equip-
ment 1,393
15,327
Installation Estimate 2,300
Approx. $ 17,627
-------
- 102 -
OPERATING COSTS
I. Chemicals
A. Chlorine when dose is 5 mg/1
Quantity = concentration x flow per day x conversion to Ibs. =
5 x 0.025 x 8.33 = l.OU Ibs/day (average)
Price of hypochlorite, HTH, with 70 percent available chlorine:
$0.28/lb.
\
\
Cost per day: l.Olj. x 0,28 _ $o M
0.70
When dose is 8 mg/1
Cost per day: $O.It3 x 8/5 = $0.69
B. Carbon
Quantity necessary when carbon filter capacity for chlorine
is 20 Ibs/cu.ft. and filter dimensions are 2.5' in depth
and 5' in diameter:
rt
Q = ^(5) x2.5 = 1;9.1 cu. ft ./filter
which has chlorine capacity of: 20 x U9.1 = 982 Ibs.
since carbon cost = $7/cu.ft.
Daily Cost: Cost of a filter unit x fraction of filter used
per day = 7 x Itf x l^U = $0.36U/day
When a chlorine dose of 8 mg/1 is used daily cost of carbon =
8/5 x $OJ6U = $0.58
II. Utilities $0.20/day
III. Labor 3.00/day
IV. Amortization
With an interest rate of 2.5 percent per year, the average
annual cost of interest over a period of 10 years is
-------
- 103 -
approximately 1.25 percent, hence daily this cost is
1.0125 x 17,627 = to.90
365 x 10
Total daily cost = $9.37.
-------
COST ESTIMATE FOR A
100,000 gpd, CONTHUOUS-FLOW, RB-TREATMENT SISTEM
WITH LOW CHLORINE RESIDUAL FOR FtDYECTIOBT AGAINST
VEGETATIVE BACTERIA AND TOOT
Item Description Cost
1 2, 8", 125 pound, iron body wedge gate valves for by-pass, $ 350
$175.00 each.
2 1, 2", 125 pound, iron body wedge gate valve for by-pass 38
safety drain.
3 1, 6", 125 pound5 iron body wedge gate valve for entrance 102
valve to treatment system,
ll Mechanical Meter, 3" size, flow range, 30 to 315 gpm with 702
2% accuracy
5 Contact timer to operate solenoid in fresh water suction 103
of pump.
6 Solenoid for fresh water supply to pump suction UO
7 Chlorine feed pump 300
8 2, Hypochlorite solution feed tanks with steel cover, 1,100
gage glass dissolving device and 1/3 HP 220 volt, 60-
cycle agitator, totally enclosed motor.
9 1, pH indicator, recorder with alarm contacts. 1,200
10 1, Chlorine indicator, recorder with alarm contacts 3>100
11 Chlorine contact tank for detention period of 5-minutes, 3*200
concrete, 15' x 7' x 7'9 complete with gravel, excavation,
laying, and backfilling.
12 2, Activated carbon filters - pressure type (including 6,UOO
carbon) (8U" diameter)
13 2, U", 125 pound, iron body wedge gate valve for by-pass to 125
waste to be used in flushing system, initiating operation, etc.
Total $ 16,760
-------
- 105 -
Cost List (Cont'd.)
Item Description Cost
Total, brought forward $ l6,?60
U; Building to house system. Needed if option of carbon
filters is chosen. Otherwise, probably not necessary 7»000
15 Miscellaneous piping 500
Total $ 2U,260
Estimate an additional 10$ for misc. 2,U26
items such as small piping, desk,
chemical testing kits, etc.
Estimate Installation at an addi-
tional 15/6 3.900
Total $ 30,586
Use: | 30,000
Option without carbon filters and without building. Assume
that space can be found in existing building for equipment.
Equipment Cost 10,860
Additional 106 1,086
f 11,91*6
Installation,
approx. 15/6 1.700
Grand Total $ 13,6U6
Use: 111, 000
-------
- 106 -
OPERATING COSTS
Continuous Flow System
Low Chlorine Residual with Carbon Filters
I . Chemicals
A. Chlorine when dose is 5 nig/1
Quantity = conctn x gpd x 8»33 = 5 x 0.1 x 8.33
= U.17 Ib/day
Price of hypochlorite (1Q% in HTH) = $0.2865/lb
Cost per day = ^.l? . ^Q . ^n
u« f ~~~~
When dose is 8 mg/1, cost per day = $2.7U
B . Carbon
Quantity when 2 filters are each ?' in diameter and 2.5' in
depth = ( x 2.5) 2 = 192 cu.ft.
c.f . capacity for C12 is 20 Ib/cu.ft.
Cost per cu.ft. = $7
Cost per day = 7 x 192 x U.17 ftl , A
20 x 192 - ei*i£
When chlorine dose is 8 mg/1, cost = 8/5 x 1.U6 = $2.3U/day
II. Utilities $0.20 per day
III. Labor " 3.00 per day
IV. Amortization 8.33 per day
30,000 x 1.0125 *Q m
10 x 365 - = $8°33
Total at 5 mg/1 $ Ui.70
Total at 8 mg/1 16.61
Without carbon filters when plant cost is $lUJ000.
Chlorine cost would be the same, $1.71 and 2.7U/day
Utilities the same 0.20/day
Labor less 2.50/day
Amortization less
x 1.012
10 x 365 "
Total $ 8.31 or $9.36
-------
- 107 -
COST ESTIMATE FOE A
500,000 gpd, CONTINUOUS-FLOW, RE-TREATMBNT SYSTEM WITH
LOW CHLORINE RESIDUAL FOR PROTECTION AGAINST
VEGETATIVE BACTERIA AND TQEffl
Item Description Cost
1 Building to house system - built of cement block, flat $ 18,000
roof, no architectural treatment. Built by private
contractor.
2 2, Hi" by-pass valve - 12Jw iron body wedge gate valve,
ft!75.00 each. 350
3 1;" by-pass drain valve - 12 5# iron body wedge gate valve 20
k Hi" by-pass pipe and fittings 803
1
5 12" treatment entrance valve - 12 5# iron body wedge gate 98
valve.
6 8" flow meter 3,900
7 Residual chlorine recorder 3*100
8 pH indicating and recording instrument 1,200
9 Temperature indicator and recorder 280
10 12" C.I. Flanged pipe and fittings, (within building) 1,82U
11 Concrete chlorine contact tank, 25' x 12.5 x 12.5, 5-min. 8,500
detention, complete with gravel, excavation, laying, and
backfilling
12 7, pressure carbon filters with appurtenant piping and 22,000
equipment.
13 Air compressor, if required. . 250
111 12" by-pass valves for cleaning, flushing, and adjusting 196
system.
15 Miscellaneous pipe and fittings. 300
$60,821
10/6 for furnishing and maintenance of
equipment 6,082
for installation estimate 9,000
Total $76,903
-------
- 108 -
OPERATING "COST
I. Chemical (when using a chlorine dose of 5 mg/l)
Chlorine - 0.5 x 8.33 x 5 = 20.8 Ib/day at #0.12/lb = $2.50
Carbon (when filter dimensions are 8' in diameter and 2.51 in depth)
Q = (7) 8 x 8 1T x 2.5 = 879.2 cu.ft.
~H~
Chlorine capacity = 20 Ibs/cu.ft.
Cost per cu.ft. = $7.00
Cost per day = (7 x 879.2) 2Q jj°gj9>2 - 7.28
II. Utilities 1.50
III. Labor Hi. 00
IV. Amortization
76,903 x 1.0125 _ „ ,0
10 x 355" " *•*•••*"
T* « •* -, - , Total $ ^6'58
If o ppm residual is used.
Chemicals C12 8/5 x 2.50 U.OO
Carbon 8/5 x 7.28 11.65
Labor and Utilities 15.50
Amortization 21.30
Total
-------
- 109 -
COST ESTIMATE FOR A
1,000,000 gpd, CONTINUOUS-FLOW, RE-TREATMENT SYSTEM WITH
LOW CHLORINE RESIDUAL FOR PROTECTION AGAINST
VEGETATIVE BACTERIA AND TOXIN
Item Description Cost
1 Building to house system, built of cement block with
flat roof and no arch. Treatment-private contractor $ 32,000
2 18" by-pass valve - 125# iron body wedge gate valves 630
3 8" by-pass drain valve - 125# iron body gate valve 50
U 18" by-pass pipe and fitting 1,U31
5 16" treatment entrance valve - 125# iron body gate valve 23l»
6 12" flow meter and controls U,200
7 Residual chlorine recorder 3,100
8 pH indicator and recorder 1,200
9 Temperature indicator and recorder 280
10 16" C.I. flanged pipe and fittings 3,230
11 Concrete, chlorine contact tank, 2k x 17.5 x 17.5, 5-min. Hj,000
detention; complete with gravel, excavation, laying, aad
backfilling
12 Hi, pressure filters U2,000
13 Air compressor 250
Hi 16" by-pass valves for cleaning, adjusting, flushing plant U68
15 Miscellaneous pipe and fitting U50
Total ft 103,523
Approximately 10$ for furnishing and
maintenance equipment 10,000
Approximately 15* for installation 16,000
Total $ 129,523
Use $ 130,000
-------
- 110 -
OPERATING COSTS
I. Chemical
A.Chlorine (when dose is 5 mg/1 for average flow)
Q = 5 x 1 x 8.33 = Ul.7 lb/day
1|2 lb/day x $0.12/lb = $ 5.0li/day
B.Carbon
Assume 20 Ib/cu.ft. chlorine capacity and dimensions of each
unit are 81 in diameter and 2.5 in depth
Ui x (8)2 <7T x 2.5 = 1758 cu.ft.
1758 x 20 = 837 day (life of carbon)
H2
Cost of Carbon = $7.00 per cu.ft.
II. Utilities 2.00
III. Labor 20.00
IV. Amortization
Total $ 77.7U/day
For 8 ppm chlorine feed
Chemicals:
Chlorine = 8/5 x 5.0li -= 8.07
Carbon = 8/5 x 1U.70 = 23.50
Labor and utilities = 22.00
Amortization «= 36.00
$ 89.57
-------
- Ill -
COST ESTffl/VTE FOR A
25,000 gpd, CONTINUOUS RE-TREATMENT SYSTEM WITH
HIGH CHLORINE RESIDUAL FOR SPORE PROTECTION
USING CONCRETE HOLDING TANK
Item Cost
Building $ 5,000.00
Flow meter and transmitter 375.00
Acid feed pump including tanks 1,180.00
Chlorine feed pump including tanks 1,153.00
Chlorine indicator, recorder, and alarm 3,000.00
pH indicating, recording and control 1,800.00
Temperature indicator and recorder 280.00
Chlorine contact tank 6,500.00
Carbon filter 1,900.00
Soda ash pump including tanks 850.00
pH indicator, recorder and controller 1,800.00
Mis cellaneou s . 5,762.00
Installation 7,500.00
Amortization 37*000 x 1.0125
365 x 10
Total $37,100.00
Operating Cost
Chemicals (Carbon, $1.82; CL,, $2.15; HoSOL, $0.782;
Na2C03,$0.20; Calgon, $0.0338) $ U.98
Labor and utilities 5-50
Total $ 20.78
-------
- 112 -
COST ESTIMATE FOR A
100,000 gpd, CONTINUOUS, RE-TREATMENT SYSTEM WITH
HIGH CHLORINE RESIDUAL FOR SPORE PROTECTION
USING CONCRETE HOLDING TANK
Item
Building
Acid feed pump
Chlorine feed and proportioning meter
Chlorine recorder, indicator and alarm
pH indicator, recorder, control and alarm
Chlorine contact tank
Carbon filters pressure type
Soda ash pump
pH indicator, recorder, control and alarm
Miscellaneous,
Installation
Total
Operating Cost;
Chemicals (C12, f?2.50; Acid, $3.12; Na2C03, $0.78; Calgon,
$1.36; Carbon, $7.28)
Labor and utilities
Amortization at 2.5% for 10 years 1.012$ x 59,000
Cost
$7,000.00
2,180.00
3,970.00
3,000.00
1,870.00
13,500.00
6,UOO.OO
1,750.00
1,780.00
8,0i|0.00
9,600.00
$ 59,000.00
$ 15.Oh/day
11.00
Total
$ hz.hh
-------
- 113 -
COST ESTIMATE FOR A
500,000 gpd, CONTINUOUS, RE-TREATMENT SffiTEM WETH
HIGH CHLORINE RESIDUAL FOR SPORE PROTECTION
USING CONCRETE HOLDING TANK
Item Cost
Building $ 21,000.00
Flow meter and chlorine feed device U,2U5.00
Acid feed pump including tanks 3,800.00
Chlorine indicator, recorder and alarm 3tl.QQ.QQ
pH indicator, recorder and controller 1,800.00
Temperature indicator and recorder 280.00
Chlorine contact tank, concrete 58,000.00
Carbon filters, pressure type 22,000.00
Soda ash pump including tanks 1,280.00
pH indicator, recorder and controller 1,800.00
Air compressor 250.00
Miscellaneous 17,725.00
Installation 22,370.00
Total $ 157,667.00
Operating Cost
Chemicals (C12, $12.58; H2SO||J $15.63; Na2C03, $3.92; $ 75.20
Calgon, $6076j Carbon, $36.Ul)
Labor and Utilities 22.00
Amortization at 20S% for 10 years 1.0125 x 172,000 U3-70
Total ft lU0.90/day
-------
- 11U-
COST ESTIMATE FOR A
1,000,000 gpd, CONTINUOUS, RE-TREATMENT SYSTEM WITH
HIGH CHLORINE RESIDUAL TOR SPORE ffiOTECTICN
USING CONCRETE HOLDING TANK
Item Cost
Building U0,000.00
Flow meter and chlorine feed device 5,156.00
Acid feed pump including tanks 5,600.00
Chlorine residual indicator, recorder and alarm 3,100.00
pH indicator, recorder and controller 1,800.00
Temperature recorder 278.00
Chlorine contact tank 100.000.00
Carbon filters, pressure type 1*2,000.00
Soda ash pump including tanks 1,1*00.00
pH indicator, recorder and controller 1,800.00
Air compressor 325.00
Miscellaneous 33,1*1*1.00
Installation 39,000.00
Total $ 273,900.00
27i*,000.00
Operating Cost
Chemicals 150.1*0
Labor and utilities 1*3.00
Amortization at 2.5% for 10 years 27t*iOOO x 1.0125 76.00
3650
Total $ 269.1*0
-------
COST OF PRECHLORINATION FOR SPORE PROTECTION
FOR A CONVENTIONAL TREATMENT PIANT
( AVG. FLOW = 0.5 MOD - MAX. FLOW 1.5 liGD)
Automatic flow proportioning prechlorinator (for a feed of
15 mg/1), chlorine feed cap. required: 15 x 1.5 x 8.33 = 187.5 Ib/day
and appurtenant equipment.
Insert nozzle 8" to proportion chlorine feed $ U,250.00
Two residual chlorine indicators and recorder with
alarm, $3,200 each. 6,1*00.00
Dechlorination feed
Max S02 feed: 6| x 1$ x 8e33 x !.5 = 16? Ib/day
Use chlorinizer with appurtenant equipment est. 2,500.00
Estimate of piping required 1,000.00
Equipment total Hi,150.00
Daily Operating Cost
Chlorine = 62x0.12 7.U5
Sulfur dioxide = 57 x 0.12 = 6.83
Amortization - Ht»l50 x 1.012 -, M
3«0 = 3B92
Labor and utilities = U.OO
Total $ 22.20
-------
- 116 -
COST OF PRSCHLORINATION FOR SPORE PROTECTION
FOR A CONVENTIONAL TREATMENT PLANT
(AVG. FLC-J 1 MOD - MAX. FLOW 3
Item
Cost
Automatic flow proportioning prechlorinator (10 mp/1 dose)
Chlorine feed capacity required: 15 x 3 x 8.33 - 375 Ib/day
and necessary equipment.
12" insert nozzle flow meter to proportion chlorine
indicator, recorder, totalizer
Two residual chlorine indicators, recorders and alarms
$3,200 each.
$ 5,160.00
6,Uoo.oo
Dechlorination feed
Max S02 feed:
338 Ib/day
Hi x 15 x 8.33 x 3
Use chlorinizer, programing feed with appurtenant equipment
Estimate additional piping required
3,000.00
1,500.00
Daily Operating Cost
Chlorine • 125 x 0.12 =
Sulfur dioxide = 113 x 0.12 =
Amortization = l6,060 x 1.012
3650
Labor and utilities =
Total Equipment $ 16,060.00
15.00
13.60
U.U6
U.oo
Total, approximate
$ 37.10
-------
- 117 -
COST OF PRECHLORINATION FOR SPORE PROTECTION
FOR A CONVENTIONAL TREATMENT PLANT
(AVG. FLOW 5 MGD - MAX. FLOW 15 MGD)
Item
Cost
Automatic flow proportioning prechlorinator (15 mg/1 dose)
Chlorine feed capacity required: 15 x 15 x 8.33 - 1875 Ib/day
Use chlorinizer 200 Ib/day, pneumatic control including
scales and necessary equipment.
16" insert nozzle with totalizer, indicator and recorder
Two, residual chlorine indicator, recorder with alarm
$3,200 each.
Dechlorination feed
Max. S02 feed: |j x 35 x 8.33
Use chlorinizer 2000 Ib/day capacity, programing feed wiih
scales and necessary equipment
Estimate additional piping required
Daily Operating Cost
Chlorine «= 625 x 0.03 -
Sulfur dioxide = 56? x 0008
Amortization
20,900 x 1.012
3650
7,500.00
6,UOO.OO
5,000.00
2,000.00
Labor and utilities
Total, equipment $20,900.00
50.00
58.00
U.OO
8.00
Total
$ 120.00
-------
- 118 -
COST OF PRECHLORINATION FOR SPORE PROTECTION
FOR A CONVENTIONAL TREATMENT PLANT
(AVG. FLOW 10 MGD - MAX. FLOW 30 MGD)
Item
Cost
Automatic flow proportioning chlorinizer (15 mg/1 dose)
Chlorine feed capacity required: 15 x 30 x 8.33 • 3750 Ib/day
Use chlorinizer UOOO Ib/day, pneumatic control
including scales and necessary equipment
2U" insert nozzle with totalizer, indicator and recorder
Two, residual chlorine indicator, recorder with alarm,
$3200 each.
Dechlorination feed
Max. S02 feed: *
x 8.33 x 30 = 3380 Ib/day
Use chlorinizer lj.000 Ib/day capacity, programing feed with
scales and necessary equipment
Estimate additional piping required
Daily Operating Cost
Chlorine = 1250 Ib/day x 0.08
Sulfur dioxide = 1130 Ib/day x 0.08
Amortization = 28,600 x 1.012
3650
Labor and utilities
$ 11,200.00
6,UOO.OO
8,000.00
3,000.00
Total, equipment $ 28,600.00
100.00
93.00
7.93
15.00
Total, approximate
216.00
-------
- 119 -
APPENDIX F
Monitoring for BW and CW Agents in Water With Fish
by
Quentin H. Pickering, Aquatic Biologist
Croswell Henderson, Aquatic Biologist
INTRODUCTION
With the development of more toxic BW and CW agents it becomes in-
creasingly important to explore all methods for the detection, identifica-
tion and measurement of contaminants in water supplies. This work was
initiated to explore the possibility of using fish for continuous moni-
toring to detect highly toxic BW and CW agents in water.
Chemical methods have been developed for the detection and measure-
ment of certain CW agents in water. However, the use of such methods to
continuously monitor water supplies would be somewhat difficult and costly„
Also, other contaminants may be used for which chemical methods have not
been developed. As fish are extremely sensitive to certain toxicants, it was
believed that a rapid and inexpensive continuous detection system could be
developed by using modifications of fish bioassay procedures.
After initial detection by fish, other methods could be used to
further estimate the type and quantity of contaminant. Fish, though not
truly selective, do have certain physiological reactions and time of effect-
concentration relationships which may be useful in identifying and esti-
mating concentrations of contaminant.
TEST FISH
The fish used for monitoring must be able to live in the normal
water supply, tolerate handling, be small and uniform, and react quickly
-------
- 120 -
to concentrations of the contaminant that would be harmful to man.
Tests were made with five species to determine their suitability for
monitoring purposes. Of these the fathead minnow, Pimephales promelas,
ranging in length from 50 to 65 mm and weighing about 1 to 1.5 grams, were
used in most of the tests. Bluegills (Lepomis macrochirus), green sunfish
Lepomis cyanellus), and goldfish (Carrassius auratus) of similar size and
weight were also used as were guppies (Lebistes reticulatus) that weighed
approximately 0.1 gram and ranged from 20 to 32 mm long. All of these
species proved suitable for use in monitoring systems.
TEST CONDITIONS
Generally, the dissolved oxygen and pH of drinking waters are such
that they will not adversely affect the test fish. However, care must be
taken to remove any toxic material such as chlorine and some temperature
adjustments may be necessary. Concentrations as low as 0.5 mg/1 of free
available chlorine may be toxic to some species of fish. Of the species
tested, bluegills and green sunfish were the most resistant. Chlorine is
somewhat more toxic in soft water and at low pH water.
Dechlorination of test waters can be accomplished by aeration and
exposure to sunlight, by passage through activated carbon, or by adding a
reducing agent. The selected reducing agent, sodium thiosulfate, added
continuously, served as the best method and agent for a continuous monitoring
system. It takes about 7 mg of sodium thiosulfate (Na2S20^) to reduce 1 mg
of chlorine, and, since it is highly soluble it can be added continuously
into the influent of a test aquarium. Sodium thiosulfate is non-toxic
to fish in the required concentrations.
-------
- 121 -
The optimum temperature range for warm water fish is from 20 to
28°C. They can tolerate gradual changes between h° and 3U°C but abrupt
changes of over 5°C should be avoided. Ordinary aquarium heaters will help
to moderate extremes and make test reactions more valid*
Dissolved oxygen levels should remain above k mgA during the tests.
Lower levels may cause fish mortality or abnormal sensitivity to some
toxicants.
Most species of fish can tolerate pH levels between 5 and 9 but pH
changes can greatly influence the toxicity of chemicals. No recommendation
is made for pH control, however, an accurate record of the pH is desirable
for subsequent interpretation' of results.
False alarms caused by heavy metals, insecticides or other toxicants
seem less likely than trouble arising from chlorine. Copper, lead and zinc
can be toxic to fish in soft water above concentrations of 0.05, 0,2 and 0.$
mg/1 respectively.
MONITORING APPARATUS
The simplest type of monitoring system that can be used is the
direct flow of water from a tap through an aquarium containing fish.
If 5 to 10 three-inch fish are used, a volume of 10 to 20 liters with a
replacement time of 1 to 2 hours is adequate to get a rapid response of
fish to possible contaminants.
Modifications are necessary in most cases to dechlorinate and control
i
water temperature. Figure 1 shows the apparatus used during this project
to monitor Cincinnati tap water which contains a small chloramine residual.
Accurate records of temperature, D.O., pH, alkalinity and hardness are
-------
FROM CONSTANT HEAD SIPHON
TO WASTE
AIR STONE
INFLUENT
ro
l
CONTINUOUS FLOW MONITORING APPARATUS
Figure 1
-------
- 123 -
useful if any estimates of concentration of possible contaminant are to
be made.
Very little maintenance is required for this continuous flow system.
Dead or diseased fish should be removed and replaced from fresh stock.
The fish should be fed about three times a week with a dry food and the
aquarium cleaned occasionally. The thiosulfate solution will have to be
prepared about twice a week. A stock of a reasonable number of test fish
should be kept on hand.
TOXICITY OF CW AGENTS
Nerve gases were considered the chemical agents with the greatest
potential for use in contaminating water. Therefore, the nerve gas, Sarin,
and a few simulants such as the organic phosphorus insecticides were used
to determine the effectiveness of a continuous monitoring system,,
The Sarin (isopropyl methyl phosphono-fluoridate) used in this
study was obtained from the Army Chemical Center in Maryland. Static
(non-renewed solutions) as well as continuous flow bioassays were made
with different types of test water at a temperature of 25°C.
A summary of static bioassay results with fathead minnows is given
in Table 1. These 2h, U8 and 96-hour TLm (median tolerance limit -
concentration that causes 50% mortality of the test fish) values indicate
Sarin to be about seven times more toxic in soft Hian hard water. It has
been stated that above pH 6.5> Hie rate of - hydrolysis of Sarin increases ten
times per unit increase in pH. So the difference in toxicity is probably
due to the more rapid breakdown of the Sarin in the hard water with higher pH.
-------
- 12U -
TABLE 1
COMPARISON OF THE TOXICITY OF SARIN TO FATHEAD MMNOWS
IN SOFT AND HARD WATER
TL for Sarin
m
(ug/liter)
Date
11/15/58
12/27/56
UA5/57
U/20/57
6/13/57
7/25/57
8/1/57
8/28/57
9/10/57
9/16/57
10/3/57
10/3/57
Average
^Dilution w
S 0
2li hrs.
5.6
U.8
8.0
10.0
U.6
7.0
5.6
-
-
-
-
6.5
ater with
F T (pH 7.U)
U8 hrs. 96 hrs.
U.2 U.2
U.U U.U
5.0 5.0
10.0 U.6
U.2 U.2
5.0 U.6
U.i 3.9
-
-
-
-
5.3 U.U
exceptionally low pH (
HA
2li hrs.
2U.O
Hi .5
Ui.o
-
U3.7
23.3
-
2U.5
22.0
2U.O
32.0
U5.5
32.1
17.9) - not
R D (pH
U8 hrs.
2U.O
Hi .5
Ui.o
-
U3.7
23.3
-
23.7
21.5
2U.O
32.0
U5.5
31.9
included
8.2)
96 hrs.
2U.O
Hi.5(1)
Ui.o
-
U3.7
23.3(2)
-
23.7
21.5
2U.O
32.0
U5.5
31.9
. in average
(2'Bioassay with dechlorinated Cincinnati tap water (pH 8.3; alkalinity 6U mg/lj
hardness 186 mg/1, not included in average.
-------
- 325 -
In the static bioassays with hard water there is no significant
difference between the 2h and 96-hour TLm values. Apparently, after the
first few hours the Sarin has hydrolyzed to sub-lethal concentrations and
if the fish do not die in the first 2U-hours they will survive at least
96-hours. On -the other hand, in the tests with the soft water, there is an
increase in the toxicity from 2k to 96-hours which indicates a less rapid
breakdown of Sarin and a possible accumulative or chronic effect on fish.
Minor differences in 96-hours TI^ values obtained under similiar test con-
ditions are due to the biological variation in different lots of fish.
Table 2 shows the variation in resistance of five species of test
fish to Sarin in soft and hard water. Bluegills were the most sensitive
whereas goldfish were the most resistant species.
t
In non-renewed solutions, the concentration of a toxicant may be
reduced, in time, by hydrolysis, oxidation or other chemical change. An
apparatus was designed (Figure 2) to conduct bioassay in continuously re-
newed test solutions. Various operational controls were built in for main-
taining different experimental conditions.
The comparative results between continuous-flow and static bio-
assays (Table 3) show that Sarin is considerably more toxic when test
solutions are constantly renewed. This would indicate a considerable reduc-
tion in hydrolysis in the continuous flow tests (solutions renewed every
200 minutes). The apparant differences in toxicity in soft and hard waters
were greatly reduced from that shown by static bioassays. Sarin, however,
was still somewhat more toxic in soft water. Differences in 2h, U8 and
96-hour TL values in both hard and soft waters under continuous flow
m
conditions indicate an accummulative effect of Sarin on fish.
-------
- 126 -
TABLE 2
COMPARATIVE TOXICITY OF SARIN TO FIVE SPECIES
OF FISH IN SOFT AND HARD WTERS
Test Fish
Bluegills
Green sunfish
Fathead minnows
Guppies
Goldfish
TLm for Sarin
Dilution
Water
Soft .
Hard
Soft
Hard
Soft
Hard
Soft
Hard
Soft
Hard
2h hrs.
7.5
23.5
15 '.2
6.5
32.1
8.3
21.0
16.1
Uig/lita
W hrs.
3.2
23.5
15 '.2
5.3
31.9
7.2
lii.5
11.8
r)
96 hrs.
3.2
23.5
15*.2
- U.U
31.9
7.2
13.8
9.8
-------
- 127 -
CONTINUOUS FLOW BIO-ASSAY APPARATUS
Figure 2
-------
- 128 -
TABLE 3
COMPARATIVE TOXICITY OF SARIN SOLUTIONS
UNDER STATIC AND CONTINUOUS PLOW CONDITIONS
TL (pg/liter Sarin)
Test Fish
Fatheads
Fatheads
Fatheads
Fatheads
Fatheads
Goldfish
Type of
Dilution Water
Soft
Soft
Cincinnati tap
Hard
Hard
Soft
Continuous Flow
2k hrs. U8 hrs. 96 hrs.
2.5
U.O
8.8
5.8
6.2
10.2
2.1
2.U
5.U
3.5
6.2
6.U
1.U
0.83
2.3
3.1
U.2
U.I
2h hrs
7.2
U.6
23.3
U2.0
U3.7
16.3
Static
. U8 hrs.
7.2
U.2
23.3
U2.0
U3.7
13.0
96 hrs.
7.2
U.2
23.3
U2.0
U3.7
13.0
-------
- 129 -
TIME OF EFFECT - CONCENTRATION RELATIONSHIPS
The usual 2h and 96-hour tests are helpful in developing assay
techniques and comparing toxicants, but for water monitoring it is necessary
to know "the significance of short exposure times such as 10 to 60 minutes.
The time of response (loss of equilibrium or death) of fish is
dependent upon -the concentration of a toxicant, with the response time
usually more rapid with increasing concentration of chemical. By exposing
fish to known concentrations of toxicant, a time of effect-concentration
relationship can be established (Figure 3). Unknown concentrations can
thus be estimated from the time of fish reaction.
Since the human tolerance of Sarin is 0.5 mg/1, fish were exposed
to this concentration and reaction time noted. Using the 50 percent loss
of equilibrium as an end point, this concentration could be detected in
eight minutesj using the 50 percent death criteria, the detection time was
twelve minutese
The time of effect-concentration curve presented in Figure k shows
the effect of water quality on the time of 50 percent death of fish.
i
Above 56 |jg/l of Sarin, the water quality (within the range studied) had
little or no effect on the reaction time of fathead minnows. Below 56 ug/1
of Sarin and witii a reaction time of 70-minutes or more, the difference in
the rate of hydrolysis of the two solutions was significant in terms of
toxicity to fish.
The general response of fish to Sarin is somewhat similar in all
concentrations, but of course each sequence of events is of shorter
duration in the higher concentrations,, With fathead minnows the initial
-------
-130-
I I I MINI 1 I I IIIMI TTTT
I I I 11 I'd
7
e
9
4
J
nftx
I ,
|,.ooo
• 50 X Oeolh
O SO X Loss of Equilibrium
I I I II
I I I II
T'm,
llOjOOO
EFFECT CURVE SHOWING THE TIME OF 50 PER CENT LOSS OF EQUILIBRIUM AND DEATH OF
FATHEAD MINNOWS EXPOSED TO KNOflM CONCENTRATIONS OF SARIN
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. 131-
- i i i i 111
i i i 111 in i i i 1111
i i i i 11 in i i i 11
I 2
5-1,000
I -
I
100
I
a
7
Soli Water
J i lliim—1 1 illi.ii—1 1 111MIL J i IJiiliL 1 1 Uiiil
Time (Minutes)
TIME OF EFFECT-CONCENTRATION CURVE SHOWING THE TIME OF 50 PER CENT DEATH OF FflTuFAn
MINNOWS EXPOSED TO KNOWN CONCENTRATIONS OF SARIN IM SOFT AND HARD WATER
Figure U
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response was an increase in the depth and rate of respiration followed
by an increase in activity. This was followed by a period of high
excitability with body tremors and then a complete loss of equilibrium
after which they soon died. The most conspicious feature was the exaggerated
respiratory action, extension of gill covers, and a wide opening of the
mouth. Extension of the pictoral fins forward was a response observed with
organic phosphorus compounds that had not been observed with other chemicals.
TOXICITY OF Btf AGENTS
While fish would not be expected to react to human disease producing
organisms, it appeared possible that a reaction may be obtained from a
neuro-toxin such as botulinum toxin. The use of this material as a possible
water contaminant had been suggested.
Samples of partially purified Clostridium botulinum type A toxin,
p 0
which assayed 3.2 x 10 to 6.8 x 10 mouse IP LD^Q per milliliter, were
obtained from Fort Detrick.
In bioassays conducted with this toxin, fathead minnows survived
concentrations of 102,000 mouse LDnQ/ml for 2k hours, and concentrations
of 17,000 mouse LD^Q/ml for 96-hours. Since these concentrations are
considerably above dangerous levels in drinking water, it does not appear
feasible to use fish for detecting botulinum toxin.
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CONCLUSIONS
1. It is feasible to use fish for detecting nerve gases such as Sarin in
water supplies since they react quickly and distinctively to concen-
trations far below the tolerance limits for humans.
2. A continuous-flow-through apparatus is the most sensitive and practical
device for water monitoring. Standard static bioassays are not as
sensitive.
3. If chlorine is present in the water, it must be removed, preferably
with sodium thiosulfate.
U. Temperature control with heaters is easily arranged, and pH and water
hardness records would be helpful when interpreting results.
5. Sarin is most toxic in low pH soft waters.
6. Fathead minnows, bluegills and green sunfish are the most sensitive to
Sarin, and guppies and goldfish are the most resistant.
7. Human tolerance levels of Sarin in drinking water (O.g mg/l) can be
detected by fish reaction in 8 to 12-minutes.
8. Time of effect-concentration relationship can be used to estimate con-
centrations of toxicant in water. Characteristic physiological responses
of fish may be used to help identify types of compounds.
9. Botulinum toxin in concentrations expected to be dangerous in drinking
water did not cause a response in fish.
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