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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development U S
Environmental Protection Agency, have been grouped into seven series
These seven broad categories were established to facilitate further
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transfer^ gr°Upi^.WaS consciously planned to foster technolog"
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3r G •
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pollutants associated with energy systems. The goal of the Program
is to assure the rapid development of domestic energy supplies in fn
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an'v ? *"* C°ntrO1 technolo§y- Investigations include
anlvseoh - ons ncue
and 6 H™1*1"1" °f energy-related pollutants and their health
tPhnn effects; Assessments of, and development of, control
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REVIEW NOTICE
This report has been reviewed by the participating Federal
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This document is available to the public through the National Technical
Information Service, Springfield, Virginia 22161.
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EPA-600/7-77-053
MAY 1977
BROMINE CHLORIDE-AN ALTERNATIVE
TO CHLORINE FOR FOULING CONTROL
IN CONDENSER COOLING SYSTEMS
by
Leonard H. Bongers and Thomas P. O'Connor
Martin Marietta Corporation
Environmental Technology Center
1450 South Rolling Road
Baltimore, Maryland 21227
and
Dennis T. Burton
Academy of Natural Sciences of Philadelphia
Benedict Estuarine Laboratory
Benedict, Maryland 20612
Contract No. 68-02-2158
Program Element No. EHE624
EPA Project Officer: Fred Roberts
Industrial Environmental Research Laboratory
Office of Energy, Minerals, and Industry
Research Triangle Park, N.C. 27711
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washinton, D.C. 20460
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ABSTRACT
Bromine chloride was evaluated as a potential alternative to chlorine
for fouling control in condenser cooling systems. Two properties of bromine
chloride were examined: decay rate in estuarine cooling water and fouling
control effectiveness.
The program was conducted at an 1100-MWe, fossil-fueled, two-unit
generating facility using estuarine water for once-through condenser cooling.
Chlorine and bromine chloride were applied continuously at levels of 0.5 ppm
or less.
Fouling control effectiveness was determined by the extent of fouling
control observed on glass panels exposed to treated and untreated cooling
water, and on the basis of condenser performance data. Decay characteristics
of bromine chloride were inferred from the analysis of cooling water by an
amperometric back-titration method, which could evaluate residual oxidant
concentrations of as little as 5 ppb.
The findings of the present study show that bromine chloride is an
effective fouling control agent when applied on a continuous basis at a
level of 0.5 ppm or less. Free hypobromous acid apparently was not present
during cooling system transit. Fouling control resulted from the presence
of bromamines.
The principal factor determining the amount of bromine chloride
required to obtain adequate control was the temperature of intake cooling
water. On the basis of decay characteristics of bromine chloride and the
relationship between biocide concentration, temperature, and fouling, a
control model was formulated which predicted the minimum amount of bromine
chloride necessary to attain adequate fouling control.
Examination of the decay characteristics of bromine chloride and
chlorine confirmed earlier reports that bromine chloride-induced oxidants
dissipate faster from estuarine water than do chlorine-induced oxidants.
The decay of both biocides showed a three-phase pattern. The initial phase
was short, and the decay was rapid. First-order decay kinetics characterized
the second phase, which persisted for about 10 min. In the third phase,
oxidant decay was relatively slow.
Advantages and disadvantages of continuous and intermittent fouling
control strategies are discussed on the basis of biological and environ-
mental considerations.
This report was submitted in fulfillment of Contract No. 68-02-2158
by Martin Marietta Corporation under the sponsorship of the U.S. Environ-
mental Protection Agency. This report covers a period from May 19, 1976 to
January 18, 1977.
111
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Abstract--- •
Figures •
Tables
Acknowledgements -
Parameters
1. Results and Conclusions
2. Recommendations
3. Introduction
4. Analytical Procedures
C12 and BrCl Measurements
Other Water Quality
Fouling Assay Procedure
5. Fouling Control with BrCl an
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C. Fouling Assay Information c_ l
Organic and Inorganic Dry Weight Content of Fouling Material
Accumulated on Glass Panels - c. 2
Statistical Evaluation of Biofouling in the Presence and
Absence of Biocides c.16
D. Economic and Availability Considerations of Bromine Chloride D- 1
E. The Shipping, Storage, and Feeding of Bromine Chloride F- 1
Shipping Bromine Chloride c. 3
Unloading and Storage _ "" p_ 3
Bromine Chloride Feeding IIIIIIII"" p" 3
Materials of Construction Ill E. 4
Handling Precautions - E_ 5
F. Site and Plant Characteristics of the Morgantown Steam
Electric Station F_ ±
Location and River Characteristics Near the Site F- 2
Cooling Water Flow F_ 2
VI
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FIGURES
Number
4-1 Time-dependent decay of TOX in solutions of Ca(OCl)2 with
deionized water (EW), NaHC03 solution, artificial sea water
solution (ASW; 20 ppt salinity), and estuarine cooling
water _ 1]L
4-2 Diagram of biofouling chamber - 14
5-1 Typical time-dependent Ca(OCl)2-induced oxidant decay in
estuarine (< 7 ppt salinity) cooling water 18
5-2 Accumulation with time of fouling material on glass panels
exposed to BrCl-treated and untreated cooling water 23
5-3 Accumulation with time of fouling material on glass panels
exposed to BrCl-treated (A, B) and C12-treated (C, D) cool-
ing water. Average temperatures of the unheated and the
heated cooling water were 24.9° and 29.4° C, respectively. 24
5-4 Accumulation with time of fouling material on glass panels
exposed to BrCl-treated (A, B) and C12-treated (C, D) cool-
ing water. Average temperatures of the unheated and the
heated cooling water were 22.9° C and 27.3° C, respectively.-- 25
5-5 Relationship between fouling coefficient (day"1) and oxidant
concentration for cooling water temperatures of 22.4°, 24.9°,
and 29.4° C, and cooling water temperature (° C) --- 29
A-1 Time-dependent decay of TOX and Ca(OCl)2 added to estua-
rine water - A- 6
A-2 Semi-logarithmic transformation of Figure A-1 A- 7
A-3 First-order decay constants, kj, plotted against their date
of determination A- 9
A-4 Representative examples of the rapid (ki) and slow (k2)
decay of C12- and BrCl-induced oxidants in estuarine cool-
ing water - - A-19
A-5 Ammonia and salinity effects on decay constants of BrCl-
and Cl2-induced oxidants--- A-23
VI1
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TABLES
Number
4-1 Results of [TOX] analyses by back- titrat ions of 500-ml
samples of estuarine CEW) and deionized (DW) water spiked
with varying volumes of Ca(OCl)2 solution--- ........ ----- ..... 9
4-2 Sampling design and schedule -------- .......................... 16
5-1 Comparison of average quasi first-order decay constants (ki)-- 19
5-2 Accumulation of fouling material on glass panels for varying
concentrations of continuously injected bromine chloride
and chlorine ................................................. 22
5-3 Accumulation of fouling material on glass panels for various
oxidant concentrations and water temperature .................. 27
5-4 Summary of water quality conditions for each biocide dose
rate during the two 15-day test runs ..................... _____ 31
6-1 ^sorted list of potential fouling organisms observed in
the Potomac Estuary .................. T ........................ „
6-2 Organic fraction as percent of total accumulated fouling
material -------------------------------- s ,,
........ - ................. 41
6-3 Organic C consumption by accumulated biomass as a function
of time and temperature ....................................... 43
7-1 Condenser performance during August and September 1976 for
condenser half-shells A and B ................................. 43
7-2 Model calculations of minimum bromine chloride dose rates
pi) and concentration of bromine chloride (Ci) at point of
injection for a range of water temperatures and cooling
water condenser flow rates ............................ . ....... 52
A-l Summary of TOX decay data calculated for a quasi first -
order model ................... _ ............ . ........... . ...... A_10
A- 2 Ammonia and salinity effects on the decay of BrCl- and
Cl2-induced oxidants ...................................... ____ A- 20
A-3 Coefficients of determination (r2) between ki and various
water quality parameters for BrCl- and C12 -derived oxidant --- A- 21
Vlll
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Number
A- 4 Slow decay constant, k2,and its relationship to k! A-24
A- 5 Summary of raw halogen decay data - A-25
C- 1 Mean total dry weight, organic weight, and inorganic
weight at days 3, 6, 9, 12, and 15 for the 15-day tests
conducted during the first study 11 August 1976 to
26 August 1976 C- 3
C- 2 Mean total dry weight, organic weight, and inorganic
weight at days 3, 6, and 9 for the 9-day tests conducted
during the first study 17 August 1976 to 26 August 1976 C- 8
C- 3 Mean total dry weight, organic weight, and inorganic
weight at days 3, 6, and 9 for the 9-day tests and days
3, 6, 9, 12, and 15 for the 15-day tests conducted during
the second study 10 September 1976 to 25 September 1976 C-ll
C- 4 Station identification codes for tables - C-18
C- 5 Summary of the statistical analysis of the among mean
station comparisons of all bromine chloride stations at
days 3, 6, 9, 12, and 15 for the 15-day test conducted
during the first study 11 August 1976 to 26 August 1976 C-19
C- 6 Summary of the statistical analyses of the among mean
station comparisons of all bromine chloride and chlorine
stations at days 3, 6, and 9 for the 9-day test conducted
during the first study 17 August 1976 to 26 August 1976 C-24
C- 7 Summary of the statistical analyses of the among mean
station comparisons of all bromine chloride and chlorine
stations at days 3, 6, and 9 for the 9-day test and days
3, 6, 9, 12, and 15 for the 15-day test conducted during
the second study 10 September 1976 to 25 September 1976 C-29
C- 8 Summary of the statistical analyses of the among mean
day comparisons of each station for the 15-day tests
conducted during the first study 11 August 1976 to
26 August 1976 - C-36
C- 9 Summary of the statistical analyses of the among mean
day comparisons of each station for 9-day tests conducted
during the first study 17 August 1976 to 26 August 1976 C-40
C-10 Summary of the statistical analyses of the among mean day
comparisons of each station for the 9-day and 15-day tests
conducted during the second study 10 September 1976 to
25 September 1976 045
IX
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ACKNOWLEDGEMENTS
This work was supported by the United States Environmental Protection
Agency under Contract No. 68-02-2158, Mr. Fred Roberts, Project Officer
Special thanks are due Fred Roberts who contributed valuable suggestions
SlSL-!1?31118 ?rouShout *his F°Ject- * are grateful to the Potomac
Electric Power Company engineering and environmental staffs and the Morgan-
£H? TfEle^ric S^on operating personnel for their assistance with
program definition and implementation. We are deeply indebted to Jack F.
Mills of Dow Chemical Midland, Michigan, for advice on handling and aqueous
chemistry of bromine chloride and to William A. DiPietro of Capital Control
Company, Colmar, Pennsylvania, for assisting us in the operation of the
bromine chloride feed equipment.
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CHAPTER 1
RESULTS AND CONCLUSIONS
1. Bromine chloride, added in continuous low-level doses to the estuarine
once-through cooling waters at one of the 575-MWe generating units at
the Morgantown power plant, proved effective for controlling biofouling.
Cooling water flows were 10 to 31 m3/sec (370 to 1100 ftVsec); dose
rates were 0.2 to 0.5 ppm BrCl;salinity was equal to or less than 7 parts
per thousand (ppt); fouling coefficients were less than 0.06/day fsee
p. 27 of text).
2. On an equal weight basis, the continuous low-level application of
bromine chloride and chlorine resulted in equally good control of
biofouling in the condensers. On an equal molar basis, therefore,
bromine chloride would be nearly twice as effective but would cost
about 2% times as much as chlorine at current market prices.
3. At ambient cooling water temperatures of 25° C and below, bromine
chloride dose requirements for effective biofouling control were very
temperature dependent, with no chemical addition necessary at tempera-
tures below 14° C (57° C).
4. Because of the ambient levels of ammonia in the cooling waters, it
was concluded that combined residuals, predominantly halamines,
would be present after dosing with either chlorine or bromine chlo-
ride. Although it was not determined whether the chlorine addition
resulted in the oxidation of bromide ion found in the estuarine water,
it is a possibility that might explain the nearly equal effectiveness
of the two halogens on an equal weight basis. In any case, free halogen
residuals were assumed to be present in insufficient amounts for control
of biofouling at this site.
5. At routinely used application levels, chlorine- or bromine chloride-
induced oxidants dissipated in three decay phases. A very rapid
oxidant loss was apparent in the first phase, which lasted less than
1 rain. The order of the reaction was not determined. Quasi first-
order decay kinetics characterized the second phase, which lasted about
10 min. In the third phase, oxidant decay was relatively slow; the
order of the reaction could not be ascertained adequately.
6. In estuarine cooling water with ambient ammonia concentrations about
equal to those of injected biocides and of 7 ppt salinity or less,
bromine chloride-induced oxidants dissipated faster than chlorine-
induced oxidants. The effluent of chlorobrominated cooling water con-
tained only two-thirds to one-half the amount of oxidant present in
chlorinated cooling water even though both fouling control agents
were applied at equimolar concentrations.
-------
7. The minimum amount of bromine chloride required to prevent the h'
fouling of the condenser cooling system could be predicted on the
basis of water temperature, bromine chloride decay, and cooling water
volume flow and transit time. vm*& water
8. The concurrent fouling assay method used in the present investigation
adequately reflected the extent of fouling control in thf IcSl coo?
ing System. ThUS, thlS foulincr accav ma+Vm/4 ,-.«, U~ J ^_- • •. .
ng conro n t cl coo
eff™;, ' -fOUling aSSay m&* can be useS to jSge S"
effectiveness of a cooling water treatment strategy.
9. The precision and accuracy of the amperometric back titration method
as used in the present investigation for analyzing cSlSg SSte? con-
^^atl°f °£ cblo™e- *** bromine chloride-indued '?
^"•"te for assessing the fouling control
pare
SS Se SK1^,*119 fOUlin? C°ntro1 ^ectiveness oe wT *
rS^ i ^ ^ dld not Provide information on the nature of the
chemical species present during cooling water transit and thei? effects
-------
CHAPTER 2
RECOMMENDATIONS
%n£% ?6 °U}^g C0ntro1 efficac/ of bromine chloride when
f±f continuously at relatively low concentrations (less tha£
1 ppm) and its relatively rapid dissipation compared to chlorine,
its use as a fouling control agent for once-through cooling systems
£-C°!!S,lder?d a? m altemative to chlorinf at estufrSfsUes
-, n a esurses
where ambient levels of ammonia are relatively high (about one-half
the applied bromine chloride dose) and salinities are less than 7 ppt.
In view of the satisfactory fouling control properties and dissina-
SS s^wST15*1" lbromamines (this report) and ^recenlfLdings
that slower decaying chloramines may cause acute toxicity to aquatic
«Sr(i lt:?TatUre reports), it is evident that bromine chloride is a
safer fouling control agent than chlorine.
3* i'nt^^0nS S5°U!d be fnitiated to e*Plore the nature of the rapid,
intermediate, and slow oxidant decay processes described in this resort
Analytical techniques should be employed that characterized diSdS '
^^ T^5' •The relative ******** of water quality parameters;
?n nvK *?' araraonia» salinity, and organic and inorganic constituents,
£•? ff • speciation should be established. OxidaSt decay should be
examined in terms of the type and concentration of oxidant-consuming
o?^Mnr?£S ^ Jf^31 WSer^ **&«* into the aquatic chemistr?
of chlorine and bromine chloride could aid in refining the minimum
biofouling control model developed in the present study and provide a
SS11 I ^sesf^g the potential environmental hazards associated with
the discharge of cooling water treated with chlorine or bromine chloride.
4. The common practice of chlorinating cooling water so that measurable
quantities of hypochlorous acid are still present at the tailpipes of
the condenser system should be re-examined in light of the present
findings that halamines provide adequate fouling control for saline
water (probably due to the oxidation of bromide ion to bromamines) .
5. In light of the observed fouling control efficacy of continuous low-
level chlorination and the striking concomitant reduction in the concen-
tration of effluent oxidants, it is recommended that a similar fouling
control strategy be explored for power plants using saline water and
high-level intermittent chlorination. The efficacy of continuous low-
level chlorobromination in fouling control should be explored at fresh-
water sites where the once-through cooling water is contaminated with
ammonia.
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CHAPTER 3
INTRODUCTION
tn ™ bio£ouli*f of condenser cooling systems causes frictional resistance
to cooling water flow and loss of heat transfer efficiency. Thus, it presents
hafh^nTf^S'6^? PJ°bleni £°r the P°wer generating industry. Chlorine
has been used effectively for many years to combat the growth of microbial
slimes and such common biofoulers as molluscs, barnacles, bryozoa, hydroids
sponges, and tunicates on surfaces of bar-racks, screens, intake tunnels, '
water boxes, and condenser tube surfaces. However, recent investigations
fof-'p^V9,76' ^5.ley 6t al" 1976; CaPuzzo et al" 1976' BoSgers et al.,
1975; Polgar et al., 1976; Stober and Hanson, 1974; and Roberts et al., 1975)
showed that chlorine residuals in discharged cooling water from power plants
can be toxic to aquatic life. Concerns about the biotoxicity of discharged
chlorinated waste and cooling water have increased in response to recent
findings that the reaction of chlorine with organic constituents of natural
waters may form stable chloro-organics which could disrupt reproductive and
other biological processes (Gehrs et al., 1974; Grothe and Eaton, 1975; Jolley
et al., 1975; Patton et al., 1975; Eaton, 1973; Pitt et al., 1975). This
potentially adverse impact on the inhabitants of receiving waters has motivated
a search for alternative biocides for cooling water treatment.
Bromine chloride may be an attractive alternative to chlorine since
bromamine, its most common derivative in ammonia-containing cooling water,
is more reactive than the analogous chlorine compound, chloramine, and thus
dissipates faster (Mills, 1973, 1975; Wackenhuth and Levine, 1974). There-
fore, bromine chloride, if applied judiciously, may be less hazardous than
chlorine.
The present project, designed to evaluate the effectiveness and environ-
mental acceptability of bromine chloride as a potential alternative to chlo-
rine for cooling water treatment, has three basic purposes:
• to determine the effectiveness of continuous low-level applica-
tion of bromine chloride in maintaining cooling efficiency in once-
through systems using low-salinity estuarine water for waste heat
rejection
• to develop a procedure for estimating the minimum dosage of bromine
chloride required for this purpose, taking into account temporal
changes in water quality factors
• to assess the environmental acceptability of bromine chloride
considering its dissipation characteristics relative to those of
chlorine.
The program was conducted at the 1100-MWe, fossil-fueled, two-unit
Morgantown, Maryland, generating facility operated by the Potomac Electric
4
-------
Power Company on the Potomac River Estuary. For a description of site and
plant design characteristics, see Bongers et al. (1975) and Appendix F.
Since biocide addition to the generating units could be controlled
independently, the experimental design, formulated in consultation with
the facility's operators, provided for concurrent testing of the two
biocides. Although some limited mixing of the two cooling streams occurred
before sampling could be completed -- somewhat complicating the interpreta-
tion of the findings --.concurrent use of both biocides eliminated the more
severe problems of sequential dosing, i.e., contending with temporally vary-
ing environmental factors.
Two 15-day trials were made; continuous dose rates of 0.50 ppm BrCl and
C12 were used during trial I, August 1976, and dose rates of 0.15 and 0.35
Ppm BrCl and C12, respectively, were used during trial II, September 1976.
Fouling control effectiveness was inferred from:
• observed biofouling rates on glass panels exposed to treated and
untreated cooling water;
• monitoring data on residual concentrations of chlorine- and bro-
mine chloride-induced oxidants in the cooling water;
• cooling system performance data.
Program findings, analysis, and interpretation are presented in the
body of this report. The aqueous chemistry of chlorine and bromine chloride
raw data, and statistical treatments of biofouling data are included as
Appendices A, B, and C. Economic, handling, and safety considerations of
bromine chloride are addressed in Appendices D and E
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CHAPTER 4
ANALYTICAL PROCEDURES
C12 AND BrCl MEASUREMENTS IN COOLING WATER
Reporting Procedure
Since we are concerned here with two halogens, chlorine (C12) and
bromine chloride (BrCl), concentrations will be reported as Total Oxidant
LTOXJ, expressed as microequivalents per liter (yeq/A) and ppm or rob (Darts
?Q7cfill0n °r billion) > ™ conformant with the standardpr^edurf (APHA
fr2nn°«/?POrtin§ T°^ Resldual Chlorine concentrations. Thus, a concen-
Sn nSi f ? Of1oxidant ?er ^ter corresponds to 35.5 ppb C12 or 57.5 ppb
BrCl. Oxidant levels were determined by the addition of iodide (I') at pH 4
Titration Procedure
* fthods were tested for their ability to reliably measure low
* °*ldant: .potentiometric titration (Eppley et al., 1976);
Up0^^1"0111^^1116^0 et al" 1976^ amperometric tiira-
tion (APHA, 1975) The method selected for field use was a modified ampero-
metric end-point detection procedure. Other techniques were rejected for
several reasons. Although sufficiently precise and sensitive, the potent io-
metric method was not suitable for field use; near the titration end-point,
time had to be allowed for the EMF to stabilize after each addition of titrant.
This may not present a problem with automatic titrators working on the prin-
ciple of the first or second derivative of EMF versus titrant volume but
for manual titration, this proved very inconvenient. '
The National Bureau of Standards (NBS) prototype chlorine flux monitor
performed well when chlorine was introduced in a distilled water matrix.
With natural water samples (i.e., those containing suspended material), it
was difficult to maintain constant flow within the instrument, and changes
in flow rate caused unacceptable calibration drift. There was a further
problem with the response time of this instrument. About 2 minutes were
required for the halogenated water to reach the electrode chamber, a delay
which complicated the analysis of differences in decay properties of the
two biocides. Because of these sampling difficulties, the prototype flux
monitor was not used for field measurements.
The amperometric method chosen for field use is a particularly conven-
ient technique because it relies only on detecting the appearance (back-
titration) or disappearance (forward titration) of a current in excess of a
residual current. Because it was essential to preserve the chemical condi-
tions of samples collected in the field as of the moment of sampling, we
developed a back- titration amperometric end-point detection method. Excess
phenylarsine oxide (PAD) was added to the samples to fix all the available
-------
oxidant and prevent it from decaying. (For example, a chlorinated cooling
water sample containing 4.5 yeq/A TOX, collected near the point of haloeen
injection, will lose TOX at the rate of about 0.6 yeq/ Vmin.) Excess PAO
was then determined by back-titration with iodine solution of known concen-
trat ion .
imc^ PrinciPles °f this method are described in Standard Methods (APHA
nil, ^fa^ cbeen rao™61^ as the only reliable standard method '
(Brungs, 1973). Because of the required detection limits, the following
instrumentation set-up was employed.
h«nv A j*1™?1 re£erence electrode (Sargent -Welch #3-30490) and a platinum-
hook indicating electrode (Sargent -Welch #3-30421) with a synchronous rotor
(Sargent-Welch #3-76485) were used throughout this study. The^iSting
current was sensed by a picoammeter (Keithley, Model 616 Electrometer) with
^i?^™1!^1 £! ° *? l V' ™e outPut was fed to astriP cha« reorder
Philips #PM8110. When the strip chart was set to a 10-mV full scale sensi-
tivity, small currents in excess of the background residual current, i.e.,
titration end points, became well-defined.
Titrant was added with a 2 -ml capacity microburet (Gilmont #P-4200)
n1™.:?™ iV6IT Precision °f ± 2 microliter. A 2-microliter addition of
0.00564N phenylarsine oxide (PAD) to a 500-ml solution (corresponding to
0.02 Ueq/£ of TOX) yielded a 5% scale deflection on the strip chart, which
far exceeded the less than II scale deflection of noise in the current trace.
For back-titrations, where PAO was present in excess, the titrant was iodine
Since the iodine solution was about 1.3 times the normality of
instrumental detection limit corresponded
The routine procedure used for TOX analysis in this study was as follows.
Immediately prior to sample collection, 1 ml of KI solution (150 g/i , fresh
daily), one ml of pH 4 acetate buffer (APHA, 1975), and, with an Eppendorf
micropipet, 500 or 1000 yl (depending on expected TOX concentration) of PAO
solution (0.00564N, commercial) were put into a 500-ml sample bottle. A
halogenated water sample was then collected in a 500-ml volumetric flask
and poured into the bottle. Finally, the sample was titrated with an iodine
solution (APHA, 1975), and TOX concentration at the tjjne of collection was
calculated from the formula:
[TOX] = „ , Wn4rt ,T N(.pAO) /
where [TOX] • total oxidant concentration ( yeq/fc )
Vg • volume of sample (ml)
VPAO = volume of PAO solution added (500 or 1000
VI2 ~ volume of I2 solution to end-point (yA )
N(I2)/N(PAO) = ratio of normalities of I2 and PAO solution
-------
It was necessary to complete a sample analysis within 40 minm-P* nf
the time KI and pH 4 buffer solutions were mixed to aJS?oSdSS?|f1- to
I2. It was also necessary to redetermine the Nd2)/NfPACn ratio ai ?«*««»?
of about 6 hours to compensate for slow and smallcha^ges in £(?a) Se
use, all containers were soaked overnight in a concentrated Cl, solution and
rinsed repeatedly with Cl2-free deionized water.* solution and
Precision and Detection Limit --
Table 4-1 contains the results of a comparison of [TOX] determinations
in deionized and estuarine water. The estua?ine water, with a saSSty of
4.4 ppt, was collected at the Mbrgantown site. Chlorine from a CafOCn, solu
tion was added to 500-ml subsamplis, which were already spiked with the re
quired KI, buffer, and PAD reagents! On the basis oftiilse lata^^e^onlerv-
saSesy to'h^n^6 T?^'8 Precision ** detection limit fSraJ tolooil
samples to be 0.05 yeq/£. This estimate was confirmed by an analysis of halo-
genated discharge cooling water at the Morgantown plant: for six determina-
UvSy. aV6rage standard deviations were 2.09 and 0.05 Ueq/?, ™
Accuracy --
The accuracy of the technique has come into question because of re-
cent observations by Carpenter and Macalady (1976). Using methods depen-
dent on iodide oxidation, they found that [TOX] analyses were not quanti-
tative for TOX in seawater. Therefore, we have examined the accuracy of
the method by titrating saline solutions spiked with Ca(OCl)2 and comparine
results with those obtained by spiking deionized water. comparing
of rh-S-6 !li j1^1^!! no difference between the results of oxidant analyses
of chlorinated deionized and estuarine water when KI, buffer, and PAD are
present prior to chlorine addition. However, in field investigations,
chlorine is present prior to reagent addition. For our accuracy tests, there-
S2U i.**^ Chlorine before the reagents. Since estuarine wkter contains
components which consume oxidant, these tests were done with deionized water
SaiS?g **?&$&***• IfS8- So11*10*5 "*re mixtures of one or more of
NaCl, KBr, and NaHC03,with Cl~, Br', and HC03' concentrations corresponding
to seawater salinities from 5 to 35 ppt. The mixtures were designated as
artificial seawater solutions (ASW) .
The tests indicated that, for a range of TOX concentrations from 1 to
14 yeq/Jl, the measured concentrations in solutions containing Cl", or Br~, or
both were always 5 to 15% lower than those in deionized water. There was
no apparent correlation between the size of the TOX deficiency and Cl~ or Br~
concentration.
The source of deionized water at the Morgantown power plant was an on-site
well. It was judged to be chlorine-free and iodine-demand free on the basis
o± forward and back-titrations, respectively. At our Baltimore laboratory,
the water source is municipal, and distilled deionized water could only be
made chlorine-free by boiling for 1 hour.
8
-------
TABLE 4-1. RESULTS OF [TOX] ANALYSES BY BACK-TITRATIONS
OF 500-ml SAMPLES OF ESTUARINE (EW) AND DEIONIZED (DW)
WATER SPIKED WITH VARYING VOLUMES OF
Ca(OCl)2 SOLUTION
Volume of ,,. __
Ca(OCl)2 w.ater
solution (ml) tyPe
0
0
1
2
5
10
10
20
40
40
DW
EW
EW
EW
EW
DW
EW
EW
DW
EW
[TOX] (yeq/A)
Mean S.D.*
0.00
0.00
0.09
0.19
0.65
1.11
1.15
2.35
4.74
4.7.7
0.03
0.02
0.02
0.04
0.02
0.02 "".
0.02
0.05
0.04
0.03
No. of
samples
3
2
2
2
2
5 -
5
2
2
2
Standard Deviation
-------
Figure 4-1 is a semi-logarithmic plot of TOX concentration versus
time for four solutions. Each solution was divided into a series of 500-ml
aliquots. The first aliquot in each series (time zero) was spiked with KI
buffer, and PAD prior to the addition of Ca(OCl)2; the reagents were added'
to the other samples at the indicated times after Ca(OCl)2 addition. The
uppermost line indicates that, for deionized water or water containing only
NaHC03, time has no effect on measured TOX levels. For the ASW solution
(NaCl + KBr + NaHC03) and estuarine water, however, there are changes in
[TOXJ from its value at time zero. There was a 15% "loss" of TOX in the
ASW System in 45 seconds, with no significant further changes with time.
The change with time of [TOXJ added to estuarine water was most dramatic-
50$ of the LTOXJ was lost in the first 45 seconds with first-order decay
thereafter. This decay in estuarine water is discussed in Appendix A.
We have been able to characterize the loss of TOX in saline water as
follows:
• the loss occurs in the presence of Cl~ or Br";
• the loss occurs immediately after chlorine addition and is
insignificant thereafter;
• no loss occurs if I" is present prior to chlorine addition (PAD
and buffer need not be present);
• the loss cannot be attributed to oxidant demand since the addition
of more Ca(OCl)2 to the system after 10 minutes produces another
5 to 15% immediate loss of TOX.
We have not discovered the reason for the non-quantitative analysis of
TOX in saline water. Since it occurs only in the presence of CL" or Br" and
in the absence of I", it is tempting to attribute it to a loss of C12 or Br2
gas_via volatization at the point of halogen injection. The conversion of
OC1" to C12 or Br2 would be favored under these conditions but should not be
significant at pH 7.5. Nevertheless, the loss occurs even when an alkaline
chlorine solution is added to an alkaline saline solution. If bromate (BrO3-)
or chlorate (C103~) were formed via the reactions:
3HC10 = 2C1" + CUV + 3H+
3HOBr = 2Br~ + Br03- + 3H+
they would not be detectable by the methods used for TOX, but still could
account for the missing oxidant. Halate ion production is favored, but would
be even more favored in the absence of Cl" or Br~ where we have not observed
a loss of TOX. Furthermore, Carpenter and Macalady (1976) could not detect
(polarographically) Br03~ in chlorinated sea water.
There is indicated, however, the formation of some oxidant species --
one that forms in the absence of I' and will not subsequently oxidize I" to I2
Although this portion of total oxidant is relatively small (5 to 15%), it
should be noted that the term "TOX" in this report must be qualified to mean
only that portion of the total oxidant which is measurable by the technique
used.
10
-------
DW or 2.3 mM NaHCO-
-0 ASW(20ppt)
o>
X
o
Estuarine water (9ppt)
_L
6 8
TIME, minutes
10
1?
14
Figure 4-1.
Time-dependent decay of TOX in solutions of Ca(OCl)2 with deionized
water (DW), NaHC03 solution, artificial sea water solution (ASW; 20 ppt
salinity), and estuarine cooling water.
-------
Interferences --
Three common constituents of estuarine water were tested for their
ability to oxidize I" and thus contribute anomalously to [lOX] measurements
The constituents were manganese dioxide, ferric oxide, and nitrite which
can yield I2 via the reactions '
Mn02 + 4H+ + 21- = I2 + Mn2+ + 2H20
Fe(OH)3 + 3H+ + I" = 1/2 I2 + Fe2+ + 3H20
+
N02 + 2H + I' = 1/2 I2 + NO + H20
The two solid phase components are expected in estuarine water because of
their ubiquitous presence in coatings on suspended material (Jenne, 1968).
The nitrite ion can be expected to be present at a low micromolar level .
The reactions of ferric oxide and nitrite with I" to form I2 should
not be thermodynamically significant at pH 4. It was observed that no I 2 was
formed when systems containing 50 ppm Fe203 or 50 uM/Z NOi were treated with
KI, buffer, and PAD.
Of the three reactions, the one involving manganese dioxide is the most
thermodynamically favored. IXiring early experiments on the apparent loss
of TOX in saline solutions, high concentrations of KI, up to 20 g/i, were
being used. These high levels of KI did not yield higher measured TOX concen-
trations, but, when 2 ppm Mn02 was also present, detectable I2 concentrations
were obtained. However, at the KI concentration of 0.3 g/l routinely used,
no interference was observed with Mn02 present at even 50 ppm.
Thus, the three possible interf erents , when present at concentrations
up to and exceeding those expected in estuarine cooling water, were not found
to produce I2 under normal analytical conditions. Conceivably, naturally
occurring ferric and manganic solid phases could be more reactive than the
commercial solids used here. The extent of natural interference was tested
by comparing [TOXJ analyses for control and actual samples. The results of
such a test appear in Table 4-1 and show no evidence of I2 formation from
components other than the Ca(OCl)2 added to estuarine water. Furthermore,
numerous analyses of a single estuarine water sample showed good precision.
This would not be the case if Mn02 were reacting to produce I2 since, as
was seen when high KI concentrations were present, that reaction is not pre-
cisely reproducible. We are confident, therefore, that all TOX concentrations
reported here represent only oxidant derived from the addition of C12 or BrCl.
OTHER WATER QUALITY PARAMETERS
Ammonia
Ammonia concentrations were measured by the phenolhypochlorite method
(Soloranzo, 1969). Water samples were collected in acid-washed polyethylene
bottles and filtered through 0.45 y Millipore filters within 20 minutes of
collection. Fifty -ml samples of filtered water were spiked with 2 ml of
12
-------
phenol solution, 2 ml of sodium nitroprusside solution
sas =
»
Salinity, Temperature. pHt and Oxygen Concentrati
on
A25° C = ^T + C°'022) (
where T = temperature (QQ
A • conductivity (m Mhos/cm) .
Conductivity was in turn related to salinity via the formula:
S(ppt> A25 (0.578).
FOILING ASSAY PROCEDURE
evalua? biofouling of treated and untreated cooling water, fouline
0 at/OUr locations: the intake embaymLnSireaS^2
5irculators, the intake condenser water box, and th
of
was delivered to each fouling chamber (FC in
standpipe mounted in a 25-liter
Figure 4-2), one tank for each _
S^oShT7 f^TS^ -Wf?r Pa^r^ by «ravit5r £rom the volume control'tank
tnrough a 7.6-cm (3.0-in) long PVC connector (3.8 on, 1.5 in ID) to the foul
ing chambers. The water level in each fouling chamber could be controlled
13
-------
Cooling Water Feed
/ Glass Panel
_ft_p*— r^-r— ~*T-T— -w^ ^^ ^ _ __
/
vc r-.tf.l^L r/
1 P^TTI ~^~
,1
Waste (a) Flow Diagram Schematic
^x" ii ,' /" -^ * ~yldss panels • ^
i ;i ; ^
-J- „ ^.r,. i*,r->-f..T_n. •*..'* i_«_-^.^v!— -Nj-v^ut^rv^^--^^. . V^\A/ltr.r 1 ,..,»! P-K-%-.^— — ^.3. water Level x/
7.6 cm i <- j| V •!-> jj" 4
LUJUJLJL__ _ |
— t //<
\ i f __ •***
^-— r-
~-|
-1
'///j
\
Wa
"•*^_
^*~^_
rrJ,
'///j
*
t
i
i
,r
ste
rrr
Wr
t
10 cm
i
1
I
^
(b) Longitudinal Section of Fouling Chamber
(c) Cross Section of a
Dual Chamber
Figure 4-2. Diagram biofouling chamber.
-------
independently by an adjustable standpipe at the discharge end Duolicate
fouling chambers were used at all stations with the exception'of the conden-
ser station, where a single fouling chamber was used; the volume flow of
water at this location was insufficient to supply duplicate chambers .
h i^6 ^^8 Cambers were 122 cm (48 in) long by 5.1 cm C2.0 in) wide
by 10.2 on (4 in) high and constructed of 0.6-on (0.25-in) PVC plate. TVo
rows of glass panels, 7.6 cm (3.0 in) by 12.7 cm (5.0 in) by 0.32 cm (0.125
in), were secured edge-to-edge in a vertical position in each fouling chamber
(Figures 4-2a, b) . Two grooves, 0.4 cm (0.16 in) deep by 0.35 on (0 14 in)
wide, were cut down the length of each fouling chamber to serve as alignment
slots for equal exposure of both surfaces of the glass panels. The two rows
of panels were positioned to provide 1.4 cm (0.56 in) clearance between each
row and from the sides of the fouling chamber (Figures 4-2c).
The glass panels functioned as fouling substrates. At a water depth of
7.6 cm, the effective fouling area of each panel was approximately 116 on2
(.7.6 cmx 7.6 onx 2 sides) . The leading and trailing edges of each panel
were not available to fouling organisms because of the edge-to-edge configura-
tlOTl*
Ten clean panels were placed in each row of each fouling chamber at
the beginning of each 15-day period. Because significant fouling occurred
on exposed edges, it was necessary to add one non-experimental, or blank,
panel at the first and last positions in each row. The 20 experimental
???ls/i? per r°w) were SrouPed ^to five serial, replicate partitions (IV in
l able 4-2) , each composed of four panels. This experimental configuration
provided a balanced incomplete block design for proper statistical sampling.
Four panels were removed from four different partitions every 3 days during
the 15-day studies, as shown in the sampling schedule in Table 4-2. When
an experimental panel was removed, it was replaced by a clean panel to eli-
minate free-edge exposure of the remaining panels.
All fouling chambers were kept in the dark throughout each study, except
when panels were being removed or physical and chemical data were being
collected. Flow rates were checked at least *>wrv 1? VIOHT<= *KT.™,
-------
TABLE 4-2. SAMPLING DESIGN AND SCHEDULE
Fouling chamber
Sampling schedul
Partition Position Day Partition
I
II
III
IV
V
1
3
1
3
1
3
1
3
1
3
2 3 n
4 III
2 IV
4 . V
2 6 I
A
4 II
2 III
4 IV
2 9 I
4 II
in
V
12 I
ii
IV
V
15 I
III
IV
V
Position
1
1
1
1
2
2
2
2
3
3
3
3
4
4
4
4
1
4
3
2
16
-------
CHAPTER 5
FOULING CONTROL WITH BrCl AND C12
One of the main concerns that led to the initiation of a study for
evaluating BrCl as a potential alternative to chlorine was the observation
that chlorine may react with ambient water constituents to produce long-lived
residuals which are toxic to aquatic life. One of the purported desirable
properties of BrCl is rapid dissipation of BrCl-induced oxidants and other
reaction products after their passage through the condenser cooling system
(Wackenhuth and Levine, 1974). As discussed in the previous sections and
in Appendix A and as demonstrated elsewhere (Mills, 1975), BrCl-induced
oxidants do indeed decay faster than C12-induced oxidants, at least in low-
salinity water.
BrCl should have a second important property if it is to be an accep-
table alternative to chlorine: it should control biofouling as effectively
as chlorine, either on a weight or a cost basis.
In this section, we present data on the decay kinetics of chlorine and
bromine chloride in estuarine water and on the effectiveness of the two bio-
cides. Effectiveness is measured in terms of fouling rates in the presence
and absence of chlorine- and bromine chloride-induced oxidants. The effects
of environmental parameters on the effectiveness of the biocide will be ex-
plored. (For discussion of concurrently assessed toxicity characteristics
of the chlorobrominated effluent, see Bongers et al., 1977).
OXIDANT DECAY IN THE COOLING WATER
In order to facilitate a comprehensive analysis of the relationships
between residual oxidant concentration and biofouling, we will first sum-
marize our experimental findings and interpretations of oxidant decay in
low-salinity estuarine water. A more extensive discussion of factors con-
trolling the decay of C12- and BrCl-induced oxidants is presented in Appen-
dix A. The raw data on which this discussion is based are included in
Appendix A as Table A-5. '~
The important parameters in oxidant characterization are the rate of
decline of residual oxidant during cooling system transit and the free and
combined halogen content of the oxidants. Examination of the time-dependent
oxidant decay, illustrated for C12 in Figure 5-1, reveals a three-phase
decay pattern. At an applied dose of 0.5 ppm (14 ueq/fc), about half of the
added oxidant was consumed within about half a minute (Phase 1, Figure 5-1);
in the next phase (Phase 2, Figure 5-1), oxidant decay was distinctly slower,
and the duration of this phase varied between 10 and 15 min. In the third
17
-------
o>
o
Circulator-Biofouling Assay
- Condenser Intake-Blofouling Assay
^r- Condenser Effluent-Biofouling Assay
0
16
32
TIME(min.)
Figure 5-1.
Typical time-dependent Ca(OCl)2-induced oxidant decay in
estuarine (<7 ppt salinity) cooling water. Bottom:
arithmetic representation. Top: semilogarithmic trans-
formation. For description of decay phases and biofouling
assay procedures, see text.
-------
phase, the rate of decline of titratable oxidant was much slower than that
during the previous phases (often, further decline was not apparent after a
contact time of about 30 min ) •
The decay pattern did not appear to be part of one single overall first-
order process. Other models consistent with higher-order decay
kinetics also indicated no single pattern.
Since 50% of the oxidant was lost in the very fast initial decay, and the
third phase appeared to fit a first-order model with b- -0.02 min'1, the
differences between the two biocides during the second phase were examined
on the basis of a quasi first-order model. Table 5-1 summarizes the decay
values measured for C12 and BrCl between 13 July and 14 October 1976.
The overall average decay constants shown in the table for C12 and BrCl
were different at the 0.001 probability level, indicating that Br-Cl induced
oxidants decayed faster than C12- induced oxidants. While no strong correla-
tion between ki values and measured water quality parameters was evident,
there was a tendency for both C12- and BrCl -induced oxidants to decay faster
with increasing salinity. At salinities above 7 ppt, C12- induced oxidants
did not decay more slowly than the BrCl-induced oxidants. See Appendix A.
We want to emphasize that the pattern of oxidant decay described here
applies strictly to low- salinity estuarine waters and applied biocide con-
centrations of 0.5 ppm (14 ueq/Z C12, 8.7 ueq/Jl BrCl) or less. Since pre-
vailing salinities were below 7 ppt, and biocide doses were 0.5 ppm or less,
the ki values reported in Table 5-1 were assumed to adequately describe
oxidant decay during the field trials. These constants are, therefore,
used in subsequent chapters for the formulation of a predictive, minimum
biocide biofouling control model.
TABLE 5-1. COMPARISON OF AVERAGE QUASI
FIRST-ORDER DECAY CONSTANTS (ki)
Halog™ k.(ave) k.(8.D.*)
C12 -0.106 min'1 0.048 20
BrCl -0.127 0.032 17
Standard Deviation
The analytical technique used to determine oxidant concentration
of the cooling water did not permit analysis of free residual oxidant or
the identification of the oxidant species. Back- titrat ion at pH 7 generated
very noisy, slowly drifting background currents, which made the instrument
unsuitable for titrations at pH 4. However, we may assume that the concen-
tration of free oxidant in the cooling water was negligible, at least during
Phase 2 and Phase 3, for several reasons. First, we could infer that the
0.5 ppm application level was less than the chlorine demand (as defined by
White, 1972, and APHA, 1975) of the cooling water since rechlorination of
the same sample gave a three-phase decay pattern similar to that observed
on the first application. The second reason for assuming "combined oxidants"
19
-------
was that water quality measurements indicated that chloro- and bromo-
derivatives could be formed. Thus, the ammonia content of the cooling water,
and pH and temperature conditions favored conversion to halamine forms within
seconds (for reaction kinetics, see Weil and Morris, 1949, and White, 1972).
Thus, we assumed that mainly combined residuals, and predominantly
halamines, were present during cooling system transit.
EFFECTS OF BrCl- and C12-INDUCED OXIDANTS ON FOULING RATES
Test Design
Biofouling was monitored at four stations. To determine biofouling po-
tential of treated cooling water, glass panels mounted in fouling simulators
were exposed to flowing cooling water at three power plant locations: (1) the
circulators -- biocide contact time of the bypass stream was about 30 sec:
(2) the intake condenser waterbox -- at this point, the biocide contact time
was about 1 to 2 min; and (3) a discharge location -- at this station, the
cooling water had an elevated temperature and a biocide contact time of about
b min. (The biocide contact time at the condenser station varied from 0.7 to
2 mm, and at the discharge station from 2 to 5 min, depending on the number of
circulators in operation; see also Figure 5-1.) Intake cooling water collected
at the trash racks in the intake embayment was used to determine the fouling po-
tential of untreated cooling water. (For plant characteristics, see Appendix F.)
Biofouling control effectiveness of BrCl and Clz was compared
during two 15-day trials. During the first trial, the dose rates of BrCl
and C12 were 1360 kg (3000 lb)/day. For the volume of cooling water treated,
the calculated dose levels were 510 ppb or, on a molar basis, 14.4 \ieq/l
and 8.9 ueq/Jl of chlorine and bromine chloride, respectively.
*
During the second test run, conducted in September 1976, biocide
dose rates were considerably lower because of the lower ambient water temp-
eratures prevailing during the month of September; i.e., since biofouling
is strongly temperature-dependent, lower dose rates are needed at lower
temperatures. Chlorine was injected at a level of 910 kg (2000 lb)/day
(340 ppb; 9.6 ueq/&), a dose rate commonly used during this part of the year.
Bromine chloride was applied at the much lower level of about 360 kg (800 lb)/
day (135 ppb; 2.4 yeqA) to allow comparison of the fouling control effec-
tiveness of the two biocides on an equal cost basis, and to indicate the anti-
fouling capability of presumed sub-optimal doses of bromine chloride.
Residual halogen levels were monitored for contact times of about
30 sec at the circulator stations, 1 to 2 min at the condenser intake water-
box (hereafter referred to as condenser station), and to 5 min at the discharge
location. (The condenser discharge water was sampled at the inlet to a 40-
ft long serpentine trough used for animal exposures and for evaluating bio-
cide decay characteristics. For details, see Bongers et al., 1977.)
20
-------
Fouling Control vs Biocide Concentration
The results of the two trials are recorded in Table 5-2 where the
accretion of fouling material, in mg of accumulated dry weight over the spe-
cified tune periods, is recorded by trial and test number, time, station
location, and oxidant concentration for each biocide type. Accumulation of
fouling material with time on glass panels is illustrated in Figures 5-2a
5-3a, c, and 5-4a, c. '
Dry weight values represent averages of eight replicate observations;
oxidant concentrations are time-weighted average values based on the analysis
ot cooling water samples collected at the same locations where the fouline
assays were conducted. The oxidant.values thus represent the biocide concen-
trations experienced by the fouling communities accumulating at the respec-
tive locations. (Further details on dose rates are given in Appendix B
Analytical results and statistical treatment of biofouling assay data are
presented in Appendix C.)
A review of all the data presented in Table 5-2 and Figures 5-2,
5-3, and 5-4 shows that fouling (of glass panels),in the absence of a bio-
cide, proceeds quite rapidly at a temperature-dependent rate. This is
evident when weight increases observed for tests 1 and 5 of trial I are
compared with those for test 1 of trial II. During the September trial,
when the ambient water temperatures were about 2° C below the August values
the accretion rate was much lower. Conceivably, this decrease in rate might
be attributable to a decrease in abundance of fouling biota in the source
water. (The importance of the ambient abundance of potential fouling biota
on the rate of fouling is discussed in Chapter 60 But, as indicated below
and in Chapter 7, temperature variation appears to explain satisfactorily the
differences between rates observed during the August and September trials.
The fouling rates observed in the cooling water at the circulator and
condenser stations in the presence of BrCl were considered lower than
those in the untreated water; the reduction was proportional to the oxidant
concentration. For example, after 15 days exposure to an average of 3.1 and
1.8 yeq/A of BrCl-induced oxidants, the amount of fouling material collected
on the glass panels was only 51 and 16%, respectively, of that observed in
the absence of biocide. (Compare tests 1, 2, and 3 of trial I in Table 5-2.)
Similar trends are evident from comparisons of observations recorded for
tests 5, 6, and 7 of trial I.
Dose-response interactions with chlorine as a biocide for cooling
water treatment followed similar trends, as is apparent from the examination
of tests 9, 10, and 11 of trial I, Table 5-2,and from Figures 5-2a, 5-3a, c,
and 5-4a, c.
Although exhibiting the same general trends as observed during the
first trial, dose-response interactions seen in the second trial did not
allow further quantitative interpretations. Two factors may have accounted
for this. First, the rate of fouling encountered during the September trial
was much less than that observed during August. Consequently, the impact of
sampling and analytical errors in September was more severe. More reliable
data might have been acquired if the exposure period had been extended.
21
-------
tsj
TABLE 5-2. ACCUMULATION OF FOULING MATERIAL ON GLASS PANELS FOR
VARYING CONCENTRATIONS OF CONTINUOUSLY INJECTED
BROMINE CHLORIDE AND CHLORINE
*
I 1
2
3
4
5
6
7
8
9
10
11
II 1
2
3
4
5
6
7
TEST DESCRIPTION
Date
11/8 - 26/8
11/8 - 26/8
11/8 - 26/8
11/8 - 26/8
17/8 - 26/8
17/8 - 26/8
17/8 - 26/8
17/8 - 26/8
17/8 - 26/8
17/8 - 26/8
17/8 - 26/8
10/9 - 25/9
10/9 - 19/9
10/9 - 19/9
10/9 - 25/9
10/9 - 25/9
10/9 - 25/9
10/9 - 25/9
Duration
15
15
IS
15
9
9
9
9
9
9
9
15
9
9
15
IS
15
15
Station
Embayment
Circulator
Condenser
Discharge
Embayment
Circulator
Condenser
Discharge
Circulator
Condenser
Discharge
Embayment
Circulator
Condenser
Discharge
Circulator
Condenser
)ischarge
BIOCIDE
Type
BrCl
BrCl
BrCl
BrCl
BrCl
BrCl
C12
C12
C12
BrCl
BrCl
BrCl
C12
C12
C12
Concentration
(ueo/fc) ppb
3.1^0.3 178
1.8 +_ 0.2 103
1.4+0.2 81
2.9 + 0.2 167
2.0 + 0.2 115
1.5+0.2 86
7.3 + 0.5 259
4-9 + 0.3 174
1.9+0.2 67
1.1 + 0.1 63
0.9 + 0.1 52
1.0^0.1 58
5.3 +_ 0.3 188
3.3^0.3 117
.6 + 0.2 57
ACCRETION FOULING MATERIAL
DWj*
Ong) (t)
11 100
16 145
22 200
30 272
130 100
29 22
32 19
25 96
24 18
22 17
59 45
13 100
17 130
14 107
41 315
15 115
9 69
28 215
DW6
(mg) (1)
79 100
19 24
49 62
63 80
346 100
30 9
ND* ND
536 154
64 18
66 19
254 73
42 100
30 71
28 67
57 136
19 45
20 45
34 71
DW,
(mg) (t
224 10
43 1
95 4
267 120
808 100
53 6
118 15
1005 124
91 11
92 11
571 71
77 100
32 42
54 70
96 125
29 38
20 26
39 51
DW12
(mg) (1)
717 100
51 7
152 21
806 112
170 100
98 58
26 15
22 13
78 46
DW15
(mg) (%)
1318 100
68 5
215 17
1589 121
297 100
159 54
33 11
21 7
87 29
** ***** *** °* "~ °" 1M~'
* No Data
glass surface. The value
-------
o
vO
o
B
1600
1400
1200
1000
800
600
400
200 -
Bromine Chloride
STATION KEY:
• Embayment (Control)
* Circulator
A Condenser
0 Discharge
*
Data Table 5-2
Trial I, runs 1 thru 4
(a)
TIME (days)
Data Table 5-3
Trial I. runs 1 thru 4
(b)
en
3 6 9
TIME (days)
12
15
Figure 5-2. Accumulation with time of fouling material on glass panels exposed to BrCl-treated
and untreated cooling water: (a) Ordinate expressed in total dry weight (TDW) per
116-cm surface area; (b) Ordinate in base 10 logarithm of total dry weight. Average
temperatures of the unheated and the heated cooling water were 24.9° C uiul 29.4° c
respectively. ' ''
-------
BROMINE CHLORIDE
c\j
on
1200
900
600
300
Data Table 5-2
'Trial I, runs 5 thru 8
(a)
C7>
-§ 2
o
3 6
TIME, days
Data Table 5-3
Trial I, runs 5 thru 8
(b)
CHLORINE
CM
-O
en
1200
900
6oo
300
0
Figure 5-3.
Data Table 5-2
Trial I, runs 9thru 11
(c)
o
>—
E
TIME, days
Data Table 5-5
Trial I, runs 9thru 11
" (d)
TIME, days
TIME, days
Accumulation with time of fouling material on glass panels
exposed to BrCl-treated (a, b) and Cl2-treated (c, d) cool-
ing water. Average temperatures of the unheated and the
heated cooling water were 24.90 and 29.40 c, respectively.
Station key as in Figure 5-2.
24
-------
BROMINE CHLORIDE
CVJ
CT»
E
300
200
100
Data Table 5-2
Trial II, runs 1 thru 4
(a)
6 9 12
TIME, days
3 _ Data Table 5-3
Trial II, runs 1 thru 4
i 2
o
I—I
o
I -
(b)
15
3 6 9 12
TIME, days
15
CHLORINE
300
CVJ
E
u
S 200
100
Data Table 5-2
Trial II, runs 1,5,6,&7
(c)
Figure 5-4.
6 9 12
TIME, days
15
a
01
E
o
sF*
3
_ Data Table 5-3
Trial II, runs 1,5,6, &7
(d)
1 -
6 9
TIME, days
12 15
Accumulation with time of fouling material on glass panels exposed
to BrCl-treated (a,b) and C12 -treated (c,d) cooling water.
Average temperatures of the unheated and the heated cooling water
were 22.9° C and 27.3° C, respectively.
25
-------
Second, it appears that less biocide was necessary to inhibit bio-
fouling during the September trial than anticipated. In particular Cl
appears to have been added in excess (tests 5-7). Certain^ as^ctf of t
September trial are important, however. The data fTable^-f £lt* i
7, trial II, and Figures 5-4a'and c) indicate tSt even L tte prLen
an apparent oxidant excess, some buildup of fouling material^ill SSr
rtSSTS7' -f ^•\an ijra?ediate ^tial accumulation and attainment of some
threshold value which remains reasonably constant with time, inde^ndent oT
biocide concentration. Whether the formation of this thin fc^flayer can
be prevented or in any way affects cooling system performance^inTS bf
seen.
Comparison of the fouling data for the discharge cooling water with
those observed in the embayment water indicates that the rate of fouling is
temperature-dependent. We observed (test 1 vs 4 and test 5 vs 8 of trif 1 1
and Figures 5-2a and 5-3a) that the accretion of fouling material in BrCl-
treated cooling water, after a temperature rise of about 4. 50 C, was higher
SpTX infa?ce? than that of untreated cooling water at ambieAt^empJSS
even though significant quantities of oxidant were still present, (te will
be shown subsequently, the differences became more pronounced after tte
XS^oPv5 W6re correc^ for *» inhibitory effect of oxiS?) ?h
£?i tr£^g PTOT S6S-dld ?6COVer so readily i*Plied that the effects of
S^n 13^? W6re I1!?81*1* *? nature and' if bi°f°uling community response
tioSlw S°f^?rSa5ly "^ nt*le ^act on the Deceiving water. Addi-
tionally, the fact that an increase in temperature can, at least in part
inhibitory effects can provide insight into the nature
' " baSlS f°r f0milatillg a ™ rational
The extent of biofouling recovery seen with BrCl during the August
trial was not evident in any of the other trial I treatment conditions.
This difference may have been the result of the relatively high initial dose
tS^T ^T^T11! C^StS 9' 10' "^ U o£ trial I. and S, 6, and 7 of
trials I and II) and the low rate of fouling at the lower water temperatures.
Clearly, our data are insufficient to determine whether the observed differ-
ences were due to the nature of the biocide.
To facilitate analysis of dose- response relationships, the loga-
rithms of the accumulated fouling material weights were calculated (see
Table 5-3) . The log- trans formed data were plotted against time on an arith-
metic scale, as shown in Figures 5-2b, 5-3b, d, and 5-4b, d. Using the
least squares method, we calculated coefficients a and b of the regression
equation y = a + bx, where the regression coefficient b, the slope of the
regression line, represented the growth constant of the fouling layer,
defined here as the fouling coefficient (FC) .
To characterize the effects of the BrCl- induced oxidants on FC,
the data of tests 1 through 3 and 5 through 7 of the August trial were
selected. Because of the strong temperature dependency of fouling processes,
runs 4 and 8 (where the water temperature was higher due to condenser heat-
ing) of the August trial were not used for the analysis of the interaction
between BrCl and FC.
26
-------
TABLE 5-3. ACCUMULATION OF FOULING MATERIAL ON GLASS PANELS FOR
VARIOUS OXIDANT CONCENTRATIONS AND WATER TEMPERATURES
Test 1
From Table 1
==*=«=«=•
2*
3+
S+
6
7*
8*
9
10
11
II 1+
2
3
4
S
6
7
— — — — ^— _
Temperature
cooling
w&tcr
C°C)
•"••••^^•^
24.9
24.9
24.9
29.4
24.9
24.9
24.9
29.4
24.9
24.9
29.4
22.9
22.9
22.9
27.3
22.9
22.9
27.3
...
Type
"•"••^••WE!
BrCl
BrCl
BrQ
Bra
Bra
Bra
a,
C12
a,
Bra
BrCl
BrCl
a,
C12
C12
— — -
Biocide
(peq/C) PP
=^— =•— ««•
0 0
3.1 178
1.8 103
1.4 81
0 0
2.9 167
2.0 115
1.5 86
7.3 259
4.9 174
1.9 67
0 0
1.1 63
0.9 52
1.0 58
5.3 188
3.3 117
1.6 57
Accumulation of fouling material
log 10 (rag DW) with time (days)*
3
1.04
1.20
1.34
1.48
2.11
1.45
1.51
2.09
1.38
1.51
1.77
1.11
1.23
1.15
1.61
1.18
0.95
1.45
6
1.90
1.28
1.69
1.80
2.54
1.48
2.74
1.81
1.82
2.40
1.62
1.48
1.45
1.76
1.28
1.30
1.53
9
•SB^^BB=3
2.34
1.63
1.98
2.43
2.92
1.72
2.07
3.00
1.96
1.96
2.76
1.89
1.51
1.73
1.98
1.46
1.30
1.59
12
2.85
1.71
2.18
2.91
2.23
1.99
1.42
1.34
1.88
IS
3.11
1.83
2.32
3.20
2.48
2.20
1.52
1.32
1.94
*
a
0.721
1.023
1.167
0.999
f 0.997**
\ 1.767**
1.280
1.230
/ 0.706**
11.667
1.137
1.340
1.320
0.864
1.127
0.863
1.413
1.113
1.008
1.279
~I
+
b*
= =====
0.1697
0.0563
0.0817
0.1517
0.1283
0.0450
0.0933
0.1600
0.0967
0.0683
0.1650
0.1117
0.0467
0.0967
0.0617
0.0273
0.0260
0.0443
— i .
r20
= ._..
0.96
0.94
0.97
0.98
1.00
0.83
0.96
0.93
0.92
0.98
0.98
0.83
1.00
0.99
0.87
0.57
0.93
Base 10 logarithms of weights reported in Table 5-2.
Data used for model development.
* T, ... . .
first:order kinetics within the specified 15-day tune
•
Represents the 6- to 15-day time span instead of the 0- to 9-day period.
2 , nZxy - ExEy
h(n-l)sxsy
-------
To evaluate the dependency of FC on oxidant concentrations, repre-
sented by [TOX] , the data observed at an average water temperature of 24 9° C
were fitted to the equation y = a + bx. The following data were used
FC
(day1)
TOX
0.1697
0
0.1283
0
0.0563
3.1
0.0450
2.9
0.0817
1.8
0.0933
2.0
to obtain a regression coefficient b = -0.0323, a y intercept a = 0.1486,
and a coefficient of determination r2 = 0.89.
* r™vih! basis Of these data' the relationship between the FC
and LTOXJ for an average cooling water temperature of 24.9° C can be des-
cribed by the expression:
FC = 0.149 - 0.0323 [TOX] ,
(5-1)
where FC = 0.149 represents the fouling coefficient in the absence of
added oxidant. The observed data (open circles) and the calculated re-
gression line are shown in Figure 5-5.
The FC-[TOX] interaction model, shown here, .assumes a linear relation-
ship over the full oxidant concentration range. This assumption may be
invalid for relatively low and relatively high oxidant concentrations. For
S3?? 06 ?e/10??1 suggfsts that, at an average cooling water temperature
of 24.9° C, fouling would be prevented at a [TOX] of 4.6 yeq/A. At about
half that value, we observed only a very small buildup, similar in magnitude
to values observed at the lower cooling water temperatures in the presence
o± excess amounts of oxidant. Conceivably, this accumulation represented
some minimal, unavoidable buildup. At any rate, further quantification of
the dose-response interaction at the higher end of the oxidant concentration
scale would require much longer exposure times than those used-in our pre-
sent investigations.
The linearity assumption may also be invalid at the lower end of the
oxidant scale. Frequently, because biological processes are insensitive to
or can compensate for the presence of relatively low concentrations of inhi-
bitors, some threshold concentration of oxidant may be required before bio-
logical rate processes deviate from control values. In the present circum-
stances, the resolution of our test procedure will not extend to character-
ization of the FC-[TOX] dependency in this range, at least not under field
conditions.
From an engineering point of view, dose-response interactions at the
low and the high end of the oxidant scale are of limited practicality. While
the effects of the very small bioaccumulation occurring at relatively high
oxidant levels apparently do not perceptibly reduce condenser performance,
28 ,
-------
(a)
fO
fc
8
o
z
_l
o
29.4 °C Observations
24.9 °C Observations
22.9 °C Observations
.20
i .12
to
o
o
CD
.04
02468
OX I DANT CONCENTRATION (/xg/l)
10
(b)
o measured values
• calculated values
I
I
12 16 20 24 28
TEMPERATURE (°C)
32
7igure 5-5. Relationship between fouling coefficient (day"1) and
a. oxidant concentration (peq/Jl) for cooling water temperatures of 22.4°,
24.9°, and 29.4° C. In the shaded area, the rate of fouling is too low
to evaluate with assay procedures used in the present study;
h. cooling water temperature (° C). Arrows indicate that the rate of
fouling is too low,at a water temperature of about 18° C.to evaluate
with present assay procedures.
-------
the rapid accumulation which would occur at low oxidant levels would be-
come immediately apparent by an unacceptable reduction in heat exchange
efficiency in the condenser.
The FC- [TOX] dependence for chlorine-induced oxidants cannot be
ascertained on the basis of available data. At 24.9° C, only two b values
are available for chlorine (Table 5-3, tests 6 and 7, trial I), and as
stated earlier, the accumulation of fouling material in the presence of the
relatively high chlorine concentrations (7.3 and 4.9 Meq/£; 260 ppb and 174
ppb, respectively) was too small or the result of too little exposure time
to allow accurate quantification. Therefore, further analyses of dose-
response interactions will be restricted to BrCl data.
ENVIRONMENTAL FACTORS AFFECTING FOULING CONTROL
The influence of environmental factors on the effectiveness of chlorine
and bromine chloride for fouling control has not been extensively studied
Not only is little known about the influence of water quality on the aqueous
chemistry of these agents in marine environment, but the influence of environ-
mental factors on the abundance of potential fouling biota has been explored
even less. r
We monitored four water quality parameters, salinity, dissolved oxygen
pH, and ammonia, plus water temperature in order to establish their impor-
tance on observed fouling rates. The findings are presented below.
Water Quality
From recent reports (Morris, 1975; Carpenter and Macalady, 1976) and
discussions in previous sections and Appendix A, it is apparent that the
salinity of the cooling water may profoundly affect the aqueous chemistry
o± chlorine in a marine environment. Salinity may also impact on biological
processes. In an estuarine environment, the abundance and biotype of organ-
isms capable of fouling condenser cooling systems may be governed by salinity
and thus may vary within wide margins. Since dose-response relationships
may be biotype dependent, salinity of the cooling water should be taken into
consideration in determining required biocide dose rate.
During the August and September field investigations, the salinity of
the cooling water remained relatively constant (5 ppt to 8 ppt, Table 5-4).
For this reason, no attempts were made to relate this small variation in
salinity to the extent of biofouling encountered during both tests.
Dissolved oxygen (DO) content of the cooling water is an important para-
meter to consider because of the suspected aerobic nature of the biological
processes occurring in the fouling layer. The rates of nutrient utilization
and bioaccretion may be controlled by oxygen depletion within the deeper
fouling layers if the oxygen concentration in the external medium falls be-
low certain levels. During our field trials, the DO content of the cooling
30
-------
TABLE 5-4. SUNMARY OF WATER QUALITY CONDITIONS
FOR EACH BIOCIDE DOSE RATE DURING THE
TWD 15-DAY TEST RUNS
TEST
CONDITIONS
Biocide Dose
Rates*
kg/day
(continuous)
ueq/A+
ppb
Water Quality
Conditions
Ambient temp.
(°C)
[NH3] (ymole/Jt)
pH (range)
Salinity (ppt)
DO (ppm)
TRIAL I
C12 BrCl
1360 1360
14.4 8.9
510 510
11 thru 26 Aug. 1976
311 ' - Range
S.D.*
24. 83 *_ 1.4 26.5/22.0
10.9 +. 3.6 16. 3/ 5.1
7.3 to 7.7
5 to 8
2.01 ± 0.56 3.3/1.1
TRIAL II
C12 BrCl
910 360
. 9.6 2.4
340 135
10 thru 25 Sept. 1976
^fi Range
S.D.*
22.94 ± 0.59 23.6/21.6
3.9 ± 0.83 5.5/ 3.1
7.4 to 7.8
5 to 8
4.04 t 0.59 4.9/ 2.5
*
Due to drift and dysfunctioning of the injection equipment, actual
BrCl injection values varied, and daily adjustments were necessary.
Microequivalents of bromine chloride- or chlorine-produced oxidants
per liter.
Mean ± 1 standard deviation.
31
-------
water varied between 2 and 4 mg/l. If oxygen contents in this range impose
metabolic control, such factors should be taken into account in the inter-
pretation of fouling rates observed in response to applied biocides.
There are no experimental data on the effects of DO on the rate of for-
mation of a fouling layer on cooling system surfaces. However, the impor-
tance of DO may be evaluated on the basis of investigations dealing with bio-
logical rate processes in sewage sludge floes and biofilms. Theoretical con-
siderations and empirical investigations by Matson and Characklis (19761
and
w™ et 1- Cwno dealt
Sat ScS^^f&S1Cm ** substrate consumption in floes and films, suggest
that dissolved oxygen concentrations in the range reported here appear ade-
quate to support unimpeded development of a fouling layer. This conclusion
is based on the following considerations. conclusion
highest dry weight accumulation of fouling material observed on a
[lass panel was 1,589 mg (Table 5-2). If a biological content of
« * A T X? assumed CJable 6'2)» a biomass of 230 mg/100 cm2 can be com-
puted. To determine the apparent thickness of the biological layer, its
density must be known. The density can be estimated on the basis of inves-
tigations carried out by Hoehn and Ray (1973) and Matson and Characklis (19761
who examined relationships between volumetric density and film thickness
™u£ SMft r?Srt?d densitjes of 50 *> 100 rng/on3 within a film thickness
range of 50 to 100 microns. Assuming 100 mg/cmT as a representative density,
we may compute a 230-micron layer thickness for the observed 230 mg of bio-
logical material/100 cm2 area. From estimates by Matson and Characklis and
Hoehn and Ray, we may further assume that the rate of metabolic processes in
the exposed surface fouling layer will be limited by the availability of
oxygen when the substrate total organic carbon content is 200 to 300 mg/Jl
mSL io™^al or^^ic carbon of our source water is less than 10 mg/SL
JUSEPA, 1970), we may assume that oxygen contents of 2 to 4 mg/Si are not
limiting fouling film development. This conclusion is supported by the
observed growth response. Since first-order kinetics were obtained during
•L v X Period» we may assume that oxygen limitation did not interfere
with the development of the fouling film.
The pH value of the cooling water is an important parameter to consider
in evaluating the effectiveness of chlorine and bromine chloride. The
undissociated molecules (HOBr and HOC1) are the active species; the ionized
species (OBr- and OCl')are ineffective. Bromine chloride, therefore, has
a significant advantage because dissociation of hypobromous acid occurs at
a higher than ambient pH value. For example, at pH 8.0, 90% of an aqueous
solution of BrCl would be present as the active species whereas, under
similar conditions, only 19% of a chlorine solution would be active (Mills,
1975). With the prevailing pH values (7.3 to 7.8) and the noted differences
between dissociation of C12 and BrCl in this pH range, the need for examin-
ing pH effects on the effectiveness of the two biocides is evident.
However, for the present study, the pH of the cooling water is unimpor-
tant. Cooling water pH may be an important consideration when estimating
chlorine dose rates for fouling prevention, especially when the presence of
free chlorine is a deciding factor. But, because our cooling water contained
a sufficient concentration of ammonia, and the chlorine and bromine chloride
dose rates were relatively low, we may assume that halamine formation
32
-------
(chloramines and bromamines) was essentially complete in all cases, and
that no free chlorine or bromine was present in the cooling water.'
This supposition was confirmed by water analysis data presented in
Table 5-4 and by investigations by Morris (1975), Mills (1975), and Johnson
and Sun (1975) on the aqueous reactions and toxicity of chlorine and bromine
chloride in the presence of ammonia. During the first 15-day trial (Table
5-4), the average NH3 concentration was 10.9 ^3.6 y mole/£ while the calcu-
lated chlorine and bromine chloride concentrations at the point of injection
were 9.6 yeq/Jl and 2.4 yeq/i, respectively. Moreover, since HOBr and HOC1
readily react with oxidizable cooling water constituents (e.g., Fe++, Mn++,
NOi, and organics), we may assume that ambient reactant levels during both
test periods were more than sufficient to convert the injected biocides into
the amine forms (2 yeq of chlorine or bromine chloride combine with 1 u mole
of NH3).
Thus, for the present study, we may assume that combined residuals,
primarily chloramines and bromamines, were the active species in fouling
control.
Temperature Effects
The temperature of the cooling water may affect fouling control in two
ways. First, the effectiveness of the biocide may increase with increasing
temperature. A number of investigators, examining the effect of temperature
on dose-response interactions, observed that sensitivity of biota to an inhi-
bitor tended to increase with increasing temperatures, but the extent of the in-
crease was frequently small and depended on biotype, physiological and develop-
mental state, and the presence of extraneous substances and other milieu
variables (Lamanna and Mallette, 1965; Capuzzo et al., 1976). For the pre-
sent study, temperature effects on oxidant inhibition will be ignored.
Second, the temperature of the cooling water may stimulate fouling.
Reports indicate that the temperature coefficient of biological processes
can usually be presented by the traditional Arrhenius equation, at least
within some narrow temperature range (e.g., Varma and Nepal, 1972; Rye and
Matelis, 1968; Reynolds et al., 1975; Oppenheijner, 1970; and Kinne, 1970).
For example, using a rotating disk unit, Davis and Pretorius (1975) examined
temperature coefficients (Qio) of biofouling and observed values of 1.38
between 10 and 30° C, -2.66 above 30° C, and 13.06 below 10° C. Qio values
of 2 were commonly observed. Fouling responses measured during the two field
trials in the present study followed the traditional temperature response
pattern.
The quantitative relationship between the observed accretion rates and
temperature was established on the basis of the data recorded in Table 5-3.
The following data sets were used to determine the dependency of FC (coeffi-
cient b in Table 5-3) on temperature:
33
-------
FC
(day1)
T (°C)
0.1697
24.9
0.1283
24.9
0.1117
22.9
0.1969
29.4
0.2085
29.4
The FC values used for the 29.4° C water temperature were calculated by
correcting the observed values (Table 5-3, test runs 4 and 8 of trial I)
for biocide effect. In making this correction, we assumed the potency of
bromine chloride to be invariant with temperature within the specified range.
Because the temperature span we are dealing with is relativelysmall (4 5° C)
and the extent of biocide activity increase with temperature observed with
some biological systems_is relatively unpronounced (Capuzzo et al. 1976)
we feel justified in making this simplifying assumption. '
inhibitor effect °n fouiing>we
FCc = FCm + °'0323 [TOX]
where FC^ is the measured value for T = 29.4°C in Table 5-3.
For runs 4 and 8, respectively, we obtain:
and
FCC = 0.1517 + 0.0323-1.4 = 0.1969
FC_ = 0.1600 + 0.0323-1.6 = 0.2085
f+ ~ - — •— •**•+* v*Wh^M*S^«\S — V/*4
These values are entered for T - 29.4°C in the table above.
Using the tabulated values, we then obtain:
FC = -0.1854 + 0.0132-T
(5-2)
This expression, with a coefficient of determination r2 = 0.86, suggests
that FC increases by about a factor of 2.5 with an increase in ambient
water temperature from 21<> C to 31° C (Qlo = 2.5), and that FC approaches
zero at an ambient water temperature of about 14° C. This latter value is
substantially less than the 18° C commonly considered the water temperature
at which fouling control is required. Practical applications of this temp-
erature response will be discussed in Chapter 7
34
-------
CHAPTER 6
EFFECTS OF BROMINE CHLORIDE AND CHLORINE
ON DEVELOPMENT OF BIOFOULING LAYERS
in various ways. First, treatment of coolinl water wi?h BrCl or S, cS be
targeted at the more sensitive processes in fhe sequence of events'2 S? e
SSn'hf JeCt;°n CyC^ £re?uency ^ intermittent fouling control procedures
could be synchronized with the occurrence of the event moit vulnerable to
thf i^S^Ti ?eC°nd' ^ aPPreciation °f the relative importance of
*£. fn tS^n±f ?Ct°r? "W^iiig the biological growth processes could
aid in the formulation of a predictive, minimum dose, fouling control model.
The purpose of this section is to place fouling control of nower
cooling systems by BrCl in a broader biological perfpecSveT FoSIng
cesses occurring on panels exposed to the relatively static conditions in open
marine environments will be compared to those observed in the dynamic ewi?on-
ment of a power plant cooling system. Regulating processes, peculiar S the
f±^f Syf ^ envirTent' Wil1 also be examined on the basis of information
SSr f ?ff -scale investigations on the formation of biological slines
under controlled environmental conditions. These studies have blen particularly
informative with respect to the mode of development of fouling communities
EVENTS IN A STATIC AQUATIC ENVIRONMENT
eC?n! studies tow addressed the broad theme of biofilm development on
SJS rates,:1J,maru}? environments. The development is characterized by
ccurrence of
,:, .
the occurrence of three distinct sequential phases.
. Pnase involves the "conditioning" of the clean surface exposed
to seawater; in the second phase, epiphytic microorganisms establish colonies
°n/i *!! condltlonea surface; epifaunal communities are the subsequent colonizers
S«™Srnfr2!?^and reproduction are believed to contribute most of the biomass
observed on solid substrates suspended in estuarine and marine environments.
During the primary event, glycoproteinaceous material and simple carbohy-
ronrS!^?nn0n JJ118^*101*8 °f the relatively dilute nutrient environment--
rS M °n ° surface and "neutralize" specific surface textures
(bechler and Gunderson, 1972). Investigations by Neihof and Loeb (1972)
fn^Llir iVv7rSK1 ^1972)' and Marshall et al. (1971) indicate that the
formation of this film is a necessary precursor to the adhesion of bacterial
colonies.
35
-------
The organic and inorganic nutrients concentrated at the solid surface
function as attractants to motile bacteria. Young and Mitchell (19721 2
ploring chemotactic responses of motile bacteria, observed that positive
chemotactic compounds enhance the rate of attachment (the orosiS response
SP? ? ^ tfic c^P0^3 "ere concentrated at the Sid-liSSdtater-
face), and empirical evidence showed that accumulation and initial rate of Sowth
of the attached periphytes are Dronortinnai tn *-ho —~i~ Zl-uZT1 _rate or g7owth
cumuaon an initial ae of owt
medial. " periphytes are P™portional to the organic carbon conten? of ?£
-
witHn-Fmatter of hours, and, according to Zobell (1943) , Corpe ( 19721 and
g;tali SSL&TSS
as ass g ;
mec°bSerV?dTabi-ity of these 8elatinous bacterial slimes to accumulate met-
est in^ool^S^te^19i52) ** agg^gate Peculate mattL isTf special
? I ?VS °ll]?fn^t?n^ouling sulce observations by Mangum and Mcllhennv
foii ^°7 (19I4) ^i^6 that cooling water chlorination^esults S^the
formation of iron and manganese precipitates? ^uj-is m tne
phas\ ^ the ^cumulative process is the colonization of the
6arly Hfe StageS Of ePifaunal communities. Although
t0iClean SUr£aCeS d° °CCUr» e'g" barnacle naupli?8
n o aye? apparently is a prerequisite for the attachment
Ctet * 11 TMsT7 mVertebrate f°Uling larvae (K^ght- Jones and Crisp? 19?3;
any organism which is capable of colonizing a surface is capable of
nV-1118 ^g^15111 to estuarine environments, an extensive list of
potential fouling organisms can be prepared. Table 6-1 presents a list of the
common, potential foulers observed in the Potomac River estuary! their salinity
preferences, and their reproductive and feeding modes. salinity
occurring on fouling panels are more limited in
• u . er estuary, a tributary of the Chesapeake Bay in
*lg. lu.reSme a the Morgantown SES, the productive members of
t fuin. . ,
h!^n,n ^^g/o^^ies are the hydroids, tunicates, barnacles, tubeworms,
bryozoa, and a tube-building amphipod (Cory, 1967).
The structure of the panel communities would be expected to reflect the
reproductive cycles of the ambient communities. Investigations by Cory (1967)
and Sutherland and Karlson (1972) indeed confirmed that the intensity of larval
setting corresponds to their reproductive periods. In Chesapeake Bay, the pri-
mary reproductive period of the fouling animals mentioned above is summer.
borne start in late spring and continue through early fall.
36
-------
TABLE 6-1. ASSORTED LIST OF POTENTIAL FOULING ORGANISMS
OBSERVED IN THE POTOMAC ESTUARY
Major group
Distributional range*
Fresh-
water
Estuarine Marine
Reproduction season
Feeding type
Mode of reproduction
PROTOZOA
(single celled organisms)
FORIFERA
(sponges)
Microciona prolifera
Haliclona permollis
Cliona truitti
CNIDARIA
(hydrozoans)
Bimeria sp.
Bouganvilla sp.
Clytia longicyatha
Cordylophora lacustris
Membranipora tenuis
Sertularid argentea
Victorella pavida
VC
R
VC
c
VC
x
x
x
VC
VC Reproduce throughout the year
primarily in sunnier.
VC Reproduce throughout the year
primarily in summer.
x Sinmer-Fall
x Late Spring-Sunnier
Simmer
VC Reproduce primarily in wanner
months, information not avail-
able on a species by species
basis.
x
X
X
X
X
All feeding types occur in
this group.
Suspension feeders without
nervous integration, weak
ability to respond to ex-
ternal stimuli.
Suspension feeders, use
tentacles to capture a
wide range of food items.
Sexual and asexual, pri-
marily by cell division.
Asexual reproduction by
budding or fragmentation
and sexual reproduction
with pelagic larval
stages.
Asexual reproduction by
budding or fragmentation
and sexual reproduction
involving alteration of
generations as well as
pelagic larval stages.
EMTOPROCTA
(bryozoans)
VC Reproduce primarily in
warmer months.
Suspension feeders which
use cilia to obtain a wide
variety of particles from
the surrounding waters.
%Asexual reproduction by
budding and sexual repro-
duction with pelagic
larval stages.
(Continued)
-------
TABLE 6-1. (Cont'd.) ASSORTED LIST OF POTENTIAL FOULING ORGANISMS
OBSERVED IN THE POTOMAC ESTUARY
00
Major group
Urnatella gracilis
Nunerous species, not
identified.
POLYCHAETA
(segmented worms)
Polydora lingi
Polydora websteri
MOLLUSCA
(oysters and clams)
Brachiodontes recurvus
Congeria leucophyta
Crassostrea virginica
CIRRIPEDA
(barnacles)
Balanus amphitrite
Balanus ijnprovisus
AMPHIPODA
Corophiun lacustre
*
A = Absent
R = Rare
C =• Common
VC = Very Common
x = Dominant Species
Distributional range*
JJjjJ" E?tuarine Marine Reproduction season
x x Information not available.
x x Information not available.
A VC VC Reproduce during all seasons,
spring-fall spawners pre-
dominate.
x Spring-early summer
x Information not available.
C VC VC Reproduce during all seasons,
spring-fall spawners pre-
dominate.
x x Spring-Fall
x Spring-Fall
x x Spring -Fall
A C VC Reproduce throughout the
year, spring -fall spawners
predominate.
x x Spring-Fall
x x Spring-Fall
VC VC VC Reproduce throughout the
year, spring-fall spawners
predominate.
x Spring -Fall
Feeding type Kbde of reproduction
Omnivores, feeding by fil- Sexual reproduction with
tering and ingesting sedi- pelagic larval stages.
ments. Eggs are often brooded.
Suspension feeders with sen- Sexual reproduction with
sory perception of the water pelagic larval stages.
quality.
Suspension feeders with sen- Sexual reproduction with
sory perception of the water pelagic larval stages.
quality.
Scavengers Sexual reproduction with
brooded young.
-------
In Chesapeake Bay, most of the productivity of panel communities occurs in
July and August (Cory, 1967). Water temperature apparently is the dominant
regulating factor in that i£ controls feeding and reproduction. When ambient
water temperatures reach 20 C, accumulation due to production by epifaunal
communities starts and usually continues until fall, when the water tempera-
tures decrease to 20°C. This pattern is observed in Chesapeake Bay (Cory, 1967;
Cory and Nauman, 1969) and other geographic locations (U. S. Naval Institute,
1952). As will be seen later, biocide use to prevent fouling of cooling sys-
tems usually starts when the ambient water temperature reaches 18°C to 20°C
and is terminated in the fall when the ambient temperature declines to that value.
Another important factor having considerable bearing on the composition and
development of the fouling community is the velocity of the water relative to the
fouling surface. This, and other pertinent environmental factors are addressed in
the next section."
COOLING SYSTEM FOULING PROCESSES AND THEIR CONTROL
A sequence of events similar to that involved in the biofouling of solid
surfaces in marine and estuarine situations can be expected to occur under the
more dynamic conditions prevailing in power plant cooling systems. An important
difference lies in the flow regime. In a cooling system, flow velocities may vary
from 15 to 30 cm/sec through the traveling screens up to 200 cm/sec through the
condenser tubes. Since development and maintenance of the initial film and the
subsequent attachment and feeding of epifaunal animals are affected (all of them
differently) by the velocity of the cooling water, the nature of the fouling
communities developing in a cooling system may vary spatially.
Another difference between the two environments is the magnitude of the
initial rate processes. The objective of fouling control measures is to limit
accumulation to a level which permits efficient operation; therefore, short-term
phenomena in the initial events must be examined. To determine the importance of
factors regulating processes resulting in the initial buildup, a relatively high
sampling frequency is necessary. Therefore, the accumulation on the glass panels
was assayed at 3-day intervals over a 15-day period, and the high replication of
the sample scheme was designed to gain sufficient precision.
Fouling Layer Development
The kinetics of biomass accretion are evident from Figures 5-2b, 5-3b, and
5-4b. The weight contribution of the initial colonization is shown by the Y-axis
intercept; the time-dependent buildup due to the growth of attached fauna (phase-3
activity) is illustrated by the series of curves reflecting the growth in the
presence and absence of BrCl.
Inspection of the relation between weight increase (per 116 cm2) and time
(in days) indicates that biomass increases exponentially during the 15-day ex-
perimental period. Since the shape of these curves reflects the nature of biological
processes, we can draw some inferences from them.
39
-------
Apparently, for the given set of conditions, the observed rates of
growth are the maximum attainable rates consistent with internal biological
processes. The exponential increase in biomass continues until external
factors impose limitations; biomass accretion then proceeds at a linear
rather than exponential rate. This change in growth kinetics should be a
consideration in defining the minimum biocide dose requirements. Further-
more, with the transition to linear growth, the nature of the metabolic pro-
cesses of the deeper fouling layer may change, thus weakening the structural
integrity of the whole layer. Large patches may then peel off the intake
conduit and waterbox surfaces and block sections of the condenser system.
In view of the aerobic nature of the phase-3 activity, the transfer of
biological reactants, such as organic carbon constituents and/or oxygen,
from the external liquid and their penetration into the biomass may become
limiting factors in its growth. The ability of a reactant to fully penetrate
the attached biomass depends on biomass thickness, consumption rate of the
reactant, and its bulk liquid concentration. The functional relationship be-
tween these variables may be estimated on the basis of bench-scale kinetic
and mechanistic studies conducted by, e.g., Hoehn and Ray (1973), Matson and
Characklis (1976), Characklis and Dydek (1976), Bintanja et al. (1976), La
Motta (1976), Whalen et al. (1969), and Bungay and Harold (1971).
The possible factors affecting the transition to linear accretion were
briefly scrutinized. Since biofilm activity is frequently reported in terms
of the consumption of organic carbon per unit area and time, biomass accretion
rates observed in the investigations were converted to organic carbon con-
sumption rate based on the assumptions and computations given below.
The organic content of the biomass was determined for all treatment
conditions. As shown in Table 6-2, the organic fraction averaged about 171
and the inert (ash) fraction about 83% of biomass. Since the ratio of organic
to ash content appeared independent of treatment conditions, all biomass was
considered to contain a biological fraction of 171, which, for the present
purpose, was assumed to consist of 50% carbon, i.e., 8.51 of the biomass was
assumed to be organic C.
The consumption rate of organic C by the fouling layer was computed,
assuming, arbitrarily, that 10% of the consumed organic C was assimilated
and converted to biomass organic C. To compute organic C consumption as a
function of temperature, Eq. 5-2 was solved for desired T values. Assuming
a Y-intercept of 1.00, we obtained the following expressions for 20°, 25°,
and 30° C, respectively:
€20 = 0.362 + 0.0786 (t)
C25 - 0.362 + 0.1446 (t)
C30 = 0.362 + 0.2106 (t)
where t = time (days),
and,
GX = base 10 logarithm of the mg organic C consumed/day/
116-cm2 surface area.
40
-------
TABLE 6-2. ORGANIC FRACTION AS PERCENT OF TOTAL
ACCUMULATED FOULING MATERIAL
For detailed data presentation, see Appendix C
(Average % Organic Matter 17*)
Test # Station Biocide
(see Table 5-2) location BrCl Cl2
I, 1
I, 5
II, 1
I, 2
I, 6
II, 2
I, 9
II, 5
I, 3
I, 7 .
II, 3
I, 10
II, 6
I, 4
I, 8
II, 4
I, 11
II, 7
Embayment
Embayment
Embayment
Circulator +
Circulator +
Circulator +
Circulator - +
Circulator - +
Condenser +
Condenser +
Condenser +
Condenser - +
Condenser - +
Discharge +
Discharge +
Discharge +
Discharge - +
Discharge - +
Organic fraction
Standard No. of
I deviation samples
19.7
16.1
18.6
20.0
17.0
19.0
15.0
17.6
15.6
15.5
19.0
17.0
21.8
16.4
15.6
18.8
14.1
16.8
7.56
1.10
2.70
3.82
1.73
1.00
1.20
3.20
2.31
--
3.46
3.00
7.72
1.70
1.52
2.86
2.00
2.86
5
3
5
5
3
3
3
5
5
2
3
3
5
5
3
5
3
5
41
-------
Table 6-3 shows the effects of three cooling water temperatures on the potential
increase in organic C consumption with time. For a 25* C water temperature in
the presence of 3 y eq/i oxidant, the expression '
TOY
C 25 - 0.362 + 0.0534 (t)
may be used.
The bulk organic C content of the cooling water was estimated on the basis
of measurements of total organic carbon (TOG) in the Potomac River estuary
(U.S.E.P.A., 1970), which showed an average value of about 6 mg/i and a range
between 11.6 and 0.63 mg/4. Using high fluid velocities to minimize external
diffusional resistance, LaMotta (1976) observed the rate of glucose utilization
by the biofilm to be independent of bulk liquid concentration in the range be-
tween 16 and 2.3 mg glucose-CA, and exponential. The cooling water value of
6 mg/i is within this range, and we also found exponential kinetics.
From LaMotta's data, a maximum rate of glucose-C consumption of 1856 mg/
116 cm2/day can be computed for a 320-micron film thickness. These values co-
incide with those projected using the expressions above relating organic C and
temperature. At 20°, 25°, and 30° C, the "LaMotta maximum" would be reached at
about the 37th day
log 1856 - 0.362
20th day
ft™
1 zu 0.0786
ft-, = log 1856 - 0.362 ,
25 } '
0.1446
and 14th day
ft™ - log 1856 - 0.362 ,
1 30 0.2106 J »
respectively. In the presence of 3p eq/i (172 ppb) BrCl, the maximum rate would
be attained after 54 days.
The apparent fouling layer thickness, determined from available data at
24.9° C in the absence of BrCl, was 230 microns (Chapter 5). If film density
remained unchanged, the 20-day projected film thickness would be 940 microns,
which is about three times the value observed by LaMotta (1976) .
Hoehn and Ray (1973) , using their own observations and literature data,
found that the transition from exponential to linear accretion occurred at a
film thickness of about 200 microns. Maier's observations, quoted by Hoehn
and Ray (1973), indicated that maximum glucose removal rates were about 10,000
mg glucose-C/day/116 cm2, occurring at a film thickness of 1100 microns.
42
-------
TABLE 6-3. ORGANIC C CONSUMPTION BY ACCUMULATED
BIOMASS AS A FUNCTION OF TIME AND TEMPERATURE
(mg C/day/116 on2)
Cooling water temperature
200 C 250 C 30o c
(Days) No BrCl No BrCl 3yeq/£(171ppb) BrCl No BrCl
5 6 12 4 26 •
10 14 64 8 294
15 35 340 15 3319
20 86 1795 27 3.7 x 104
25 212 9484 50 4.2 x 10$
Values are calculated on the basis of the following expressions:
C20 • 0.362 + 0.0786 (t). No bromine chloride.
C25 = 0.362 + 0.1446 (t). No bromine chloride.
C30 = 0.362 + 0.2106 (t). No bromine chloride.
TOX
C25 = 0.362 + 0.0534 (t). 3yeq/£ bromine chloride.
t = time in days
43
-------
These estimates of maximum film thickness and C consumption assume an
adequate supply of oxygen for carbon metabolism. Observations by Hoeta a^d
Ray (1973) Bungay et al. (1969), and Whalen et al. (1969) Sdicate?£t
oxygen supply frequently becomes rate-limiting when bulk liquid nutrient
1?f10^ ^ relf 1Vfly high' ^ that biomass accretion is rlre?y
r/*7 Tg% SUPPly Wh?n bulk nutrient concentration is less than about
th, . hS PreSGnt ^r5*18**10113' diss°lved oxygen values were about
, thus, we may assume that oxygen supply satisfied the demand ConceivaMv
lower oxygen levels may well limit the attainable layer thicknSTto much lowS Y
values than those discussed above. Whether low bulk liquid SnclnSaUons con-
rS^T^fT™1^11 suf£iciently to obviate the need fo? coolSg Sater
fn,!^en? Wlll.1f 8J1 y dePend on °*ygen transfer characteristics at the Uquid-
fouling layer interface. Oxygen flux across the interface layer depends Sits
thickness, which is determined by the flow velocity at the surface.
Fouling Control Strategy
Fouling control procedures can now be considered in the context of the
biological events addressed thus far. The control parameters to be considered
are the minimum effective dose and the frequency and duration o?
mjor
First, we may consider prevention of the development of the initial micro-
ariSS* ? ?6 e?ectation that its Prevention^would inhibit the su£s££ent
attachment of epifaunal organisms and might also reduce or prevent the accumu-
xation ox scale deposits.
Since the development of the microbial slime layer is initiated by the
aggregation of microbes already present in the cooling water, the initial de-
velopment most likely is extremely rapid. Whether attachment can be prevented
is moot. Removal of the bacterial slime layer with BrCl or C12 apparently is
also very difficult. Required dose and contact time estimates^? be based on
empirical work by Characklis and Dydek (1976). Hypochlorite concentrations of
25 ppm were unable to inactivate an established slime biomass; additions of
250 ppm hypochlorite were required to completely remove the slime layer in
2 hours. The authors suggest that such high concentrations are required be-
cause chemical oxidation rather than bactericidal effect is needed for film
detachment. Beauchamp (1969) reported that chlorine concentrations of 2 to 3
ppm, applied at 6-hour intervals for 15 min per cycle, prevented slime formation
in a power plant cooling system. White (1972) notes that a dose as high as 4 ppm
may be required for a few days to remove slime accumulations. In view of the
relatively high chlorine levels necessary for removing an established slime layer,
and existing environmental restrictions on such high levels, this method of
controlling fouling does not look promising, at least for once-through cooling
i Vo wdlld •
We may now consider the initial attachment of early life stages of epi-
faunal animals to the established microbial film and their subsequent exponential
growth phase. The rationale for considering this approach is based on the
common notion that early life stages are often more sensitive to control by
L12 or BrCl than their adult stages. Data in support thereof are provided by a
number of investigators. For example, Beauchamp (1969) found that 0.5 ppm
44
-------
chlorine, applied continuously, prevented fouling by mussels- 2 to 3 n™
applied for 15 min every 6 hours, did not control mLsTfouiing BaScle
nauplii exposed for 5 min to 2.5 ppm total (applied) chlorine showed 80%
mortality (McLean, 1973) . Mangum and Mcllhenn^ (1974) foSd thaTit takes
several days and sometimes a full week for an adult barnacle to die in a
LPi!? S f ef ironment- Straufrm (1972) found that barnacle settlement
a week lor ' 7 intermittent ^plication of 1 to 5 ppm chlorine once
h, r , (i9Z2) indicated that hard-shelled organisms could most effectively
nf S£ M • 7 cont?u°us low-level chlorination that produced 0.25 to OS ppm
" e
dose autto3 C°nf S6r PiP65' CIMs ^Plies an appl
dose of about 2 to 3 ppm for seawater.) Relini and Oliva (1972) reported that
^niHf f f UOUS chlorinatlon Prevented settlement of serpulids; for killing
adults, a 1-hour exposure to 600 ppm of chlorine was required. ^^ng
On the basis of a 2-year investigation, Lamb (1972) concluded that marine
fouling can adequately be controlled by continuous application of less than
ioP,Pm4C^°rine' and that U was neither necessary to compensate for the chlorine
demand of seawater nor to maintain a certain residual in the effluent in ordeTto
secure effective control. Investigating the relative merits of intermittent and
continuous application, Mangum et al. (1972) showed that a high frequency of
application and increased chlorination tijne per cycle were important factors for
achieving effective control. White (1972) indicated that soft-bodied formf
(e.g., bryozoa, sponges, tunicates) could be adequately controlled by inter-
mittent chlorination yielding a 1-ppm concentration of free available chlorine
at the end of a 1-hour contact time, with a repeat cycle of 8 hours.
From the data presented in previous chapters, it is evident that much
lower concentrations than the ones shown above can achieve effective control
in an estuarine environment. These results show that continuous low- level
application of 0.5 ppm (applied dose) bromine chloride or chlorine can provide
adequate protection during the summer, when ambient water temperatures are
^ C and the magnitude of fouling may be considered at its maximm. Lower
dose rates were adequate with lower ambient water temperatures.
Our findings also indicate that it is not necessary to maintain a free
rYo^f iVe?idual to achieve effective control. On the basis of White's
jiy/^J definition of halogen demand, we may assume that the applied dose was
less than the demand, and, on the basis of the ammonia content of the cooling
water, it appears likely that the chemical species present during cooling system
transit were chloramines and bromamines. These compounds apparently are
effective fouling inhibitors.
Continuous application of bromine chloride or chlorine is considered a
more effective control strategy than intermittent for the following reasons.
Daring the exponential phase, biomass accretion is controlled by internal
biological processes. Inhibition of those growth-regulating processes ought
to be the most effective way of exerting control. The alternative to the control
ot the biological processes would be to meet the oxidant demand of the cooling
water by chemically oxidizing nutrient constituents. This would limit growth
by reducing the flow of energy and utilizable organic carbon from the bulk of
the liquid to the biomass. Since energy and organic carbon are available in
excess of need, oxidant addition would have to be adjusted to remove just that
excess before an energy and carbon deficiency would be achieved.
45
-------
Control of bioaccretion by continuous low-level application thus
appears the most promising approach, unless destruction through chemical
oxidation and subsequent removal of the biomass is the objective.
46
-------
CHAPTER 7
DEVELOPMENT OF A BIOFOULING CONTROL
MDDEL AND ITS APPLICATION
effectiveness of bromine chloride in controlling glass
a hr deqUa? J? tete^te the important effects of SmplraSre
Xl^n FesPSnses of rapine fouling organisms to bromine chloride into a single
framework. However, to validate the model's application to the power plant
til* «*»! 0^ the system'is truly
In the power industry, the effectiveness of cooling water treatment is
routinely evaluated on the basis of condenser performance. Similar data were
used here to relate glass panel fouling control to cooling system fouling control.
Condenser performance was inferred from the condenser "cleanliness factor "
computed in accordance with the standard procedures used by steam plants in coA-
ducting condenser performance tests. Data on condenser performance, supplied by
S!S,PiS ?T?mel^are. reC°rJed " Table 7-1' The data, which were average7
values calculated on the basis of measurements taken once a day, showed little
change over the 2-month period. On the basis of these data and opinions expressed
by power plant personnel, we assumed that cooling system performance remained
normal during the two periods when bromine chloride was used instead of chlorine
and, therefore, that glass panel fouling assays adequately reflected cooling
system fouling control. 5
An additional assumption made was that chemical composition of the source
water did not change drastically. Small variations in the so-called chlorine
demand of the intake cooling water were ignored; to the extent that they occurred
in the Potomac River estuary at the Morgantown site, it was assumed that they were
not important in terms of fouling control when the cooling water was treated con-
tinuously.
MDDEL DEVELOPMENT
A linear model structure was used to describe the relationship between bio-
touiing, temperature, and concentration of bromine chloride residuals. The
limited data output of the field trials did not permit consideration of inter-
action terms and more complex modeling procedures. As a first approximation,
we postulate the following form:
47
-------
TABLE 7-1. CONDENSER PERFORMANCE DURING
AUGUST AND SEPTEMBER 1976 FOR
HALF-SHELLS A AND B
Period
— — — — — — _
8/1/76
to
8/10/76
8/11/76
to
8/28/76
9/1/76
to
9/31/76
Biocide*
(ppm)
— — —— — — — — _ -^_
C12
0.35
BrCl
0.55
BrCl
0.15
^_
Condenser Standard Number of
Performance** deviation samples
ABA BAB
75.07 80.96 3,07 .6.66 7 7
72,88 69.98 3.48 7.50 15 15
73.91 68.51 7.52 7.22 20 20
-
Applied feed rate. Application was continuous with the exception of
short off-periods for maintenance. Data from Unit #1. Data supplied
by Potomac Electric Power Company, Washington, D.C. 20006.
**Condenser performance is the actual heat transfer rate expressed as \
of the expected heat transfer rate. For details see "Standards for Steam
M io?nCondensers"; Heat Exchange Institute; New York, N.Y. 10017, Sixth
ijCLj j.y/ u •
48
-------
FC = f (T, [TOX])
where FC = the coefficient of fouling (day"1)
T = the water temperature (° C)
[TOX] = the concentration of bromine chloride-
induced oxidants, (yeq/£)
and assume that the function can be expressed as:
FC = A • T + B •[TOX] +C
where A, B, and C are constants (independent of T or [TOX]).
The ideal way of determining values for A, B, and C is by multiparameter
regression. However, data at hand were insufficient for that purpose. Instead,
we selected values for A and B from the expression for linear dependency of
FC on T and FC on [TOX] , respectively, as shown in Chapter 5, Eqs. 5-1 and 5-2.
Thus,
A = 0.0132 and B = -0.0323 .
The value of C (Eq. 7-1, above) can be determined by substituting FC » 0.149,
A = 0.0132, and T = 24.90 c in Eq. 7-1 for [TOX] » 0. Thus, C = -0.1797. The
postulated conceptual model takes the following form:
FC-0.0132-T - 0.0323 [TOX] - 0.1797 (7-2)
From this expression, we calculated regression lines for relationships between
fouling and oxidant levels for water temperatures of 29.40 C, 24.9° C, and 22.9° C;
plots of the observed dose-response interactions are shown in Figure 5-5.
With the exception of the observations made at 22.9° C (Figure 5-5, squares),
where data were limited, all values were used for model formulation. To test the
validity of the model would require measurements of fouling material accretion
over a range of environments and temperatures (at least IQO C) at biocide levels
that inhibit the fouling from 20% to 70% of control values. Presently, such data
are not at hand.
49
-------
APPLICATION OF THE PROPOSED MODEL TO M3RGANTOWN SES
^ 7'2» the Cession can be re-
condenser = °'41 ' T ' 7-42 (7.3)
[TOX] values
^
nd'on^tr ^^ de?y-aS & &nctl°11 of contact '^ Tnlselars
pend on site- specif ic conditions and the configuration of the cooling system
Sort ^Y1*6; the inmediate biocide demand of the cooling SS^y'hSS'
' ^ on it» Content of oxidizable Sor-
nitrite, sulfide, and sulfite), organic
acids)' '
alS° te a ^^^ °f the amount of biocide
C0olln8 water- As discussed earlier, the initial decay
senn efremely raPid «* could only be estii^ted from our field
n Allowed predictable first-order kinetics. Bo?h the immediate
and subsequent oxidant consumption were accounted for as described below.
50
-------
Since condenser cleanliness is paramount to efficient performance of the
cooling system, the oxidant level during condenser passage was considered critical
to the overall performance of the system. To maintain the desired level of oxidant
at this point in the system, the decay equation oxioant
ln ^circulator ' ln ^ condenser + °'126 '* (7-4)
t determine the Celine in oxidant concentration as a function of contact
time in the system between the circulators and the condensers. The quantity t de-
innSeStion T^nr ? ^tioning circulators. With one, two, or three circulators
SrS S i t.ejV313 2, 1. °r °-67 nun, respectively. Because of the three-phase
tween O^S""^ dlSCUSSed earlier> variation in t is restricted to values be-
To account for the immediate demand consumption, the [TOX1 at the circulator
was multiplied by a factor of two. Microequivalents oxidant were then multiplied
by 57.5 to convert to micrograms of oxidant. The required minimum dose was cal-
S1^! r ^ -ems °£ weifht of b™™ chloride per day, based on the volume flow
ot the cooling water and t as defined above.
By combining Eq. 7-3 and Eq. 7-4, we obtain:
^ ^circulator = ^ (0.41 T - 7.42) + 0.126* t .
We can calculate the injection concentration from the following expression:
In (0.41 T - 7.42) + 0.126. t - 2.16 (7-5)
where C± is the concentration of biocide in ppm required at point of injection
to keep FC at the condenser from exceeding 0.06 day"1.
To calculate the minimum injection dose (DJ) in kg and Ib of bromine chloride
per day, expressions Eq. 7-6a and 7-6b, respectively, may be used:
In (Dp = In (0.41 T - 7.42) + In 00 + 0.126- t * 2.32 (7-6a)
In CDj) = In (0.41 T - 7.42) + In (V) + 0.126 -t - 0.47 (7-6b)
where V is the cooling water volume flow in m3/sec (7-6a) and cfs (7-6b) . In
Table 7-2, we record some typical dose rates and injection concentrations for BrCl,
using cooling system design characteristics applicable to the Morgantown SES and
an ambient temperature range appropriate for biocide addition.
51
-------
TABLE 7-2. MODEL CALCULATIONS OF MINIMUM BROMINE
CHLORIDE DOSE RATES (Pi) AND CONCENTRATION OF
BROMINE CHLORIDE (Ci)* AT POINT OF INJECTION
FOR A RANGE OF WATER TEMPERATURES AND
COOLING WATER CONDENSER FLOW RATES
Ambient
water
temp .
(°C)
20
21
22
23
24
25
26
27
28
29
30
V = 10.36m3/sec
V = 370 cfs
t
1
(Ppm)
0.116
0.177
0.237
0.298
0.359
0.420
0.481
0.542
0.602
0.663
0.724
= L min
/te\ Vib \
[ day H Hay )
106 234
161 355
217 478
273 602
328 723
383 844
439 968
495 1091
551 1215
606 1336
662 1459
V = 20.44m3/sec
V = 730 cfs
t = 1 min
1
(ppm)
0.102
0.156
0.204
0.263
0.317
0.370
0.424
0.478
0.531
0.585
0.638
D.
(day /Hay 1
184 406
281 619
377 831
474 1045
571 1259
668 1473
764 1684
861 1893
958 2112
1055 2326
1151 2538
V = 30.80m3/sec
V = 1100 cfs
t = 0.67 min
Ci
(Ppm)
0.098
0.149
0.201
0.252
0.304
0.355
0.406
0.458
0.509
0.561
0.612
Di
/. \ /< \
/_kg_Wlb \
1 day II day I
266 586
406 895
546 1204
685 1510
825 1819
965 2127
1105 2436
1244 2743
1384 3051
1524 3360
1664 3668
*Ci is defined as the minimum bromine chloride requirement at point of
injection to prevent the coefficient of fouling (FC) at the condenser
from exceeding 0.06 day"1.
52
-------
MODEL VALIDATION
In its present form, the "minimum biocide model" provides a reasonable
approximation of the minimum bromine chloride demand at the Morgantown site
The validity of the model for other environmental settings and other oxidant-
producing biocides, such as chlorine, can be tested in two ways.
First, historical information on biocide use, collected under a variety
of operating conditions and encompassing fresh and saline waters of known
water quality, can be compared to model calculations. Such information if
it is based on comprehensive monitoring and includes some measure of residual
fouling or condenser performance, ought to suffice for model calibration and
verification.
The second, and most direct, method of calibrating the model and establish-
ing its credibility is to collect dose-response data in representative environ-
ments over a range of ambient temperatures, providing a basis for comparisons
between empirical observations and model calculations. Aquatic environments of
special interest are the following:
• Freshwater environments with relatively high ammonia content.
Data should be collected for both chlorine and bromine chloride
as fouling control agents; bromine chloride, which forms re-
active amines with ammonia, might be the more suitable biocide
here, especially if chlorine forms less reactive, slower decaying
chloramines. The difference in chemistry will affect the oxidant
term B ITOXJ, Eq. 5-1, in the model; the difference in decay could
affect the dose required (DI in Eq. 7-6) to achieve adequate foul-
ing control. Since the data collected would be peculiar to fresh-
water fouling species and freshwater communities and may affect
both model terms, a freshwater model may be indicated.
• A low salinity (oligohaline or mesohaline) estuarine environment,
as exists at the Morgantown site during the summer. In this region,
where salinity varies from fresh water to about 10 ppt, the abundance
and biotype of potential fouling biota are governed primarily by
salinity and may oscillate within wide margins. Dose-response
data collected at such a site would therefore cover a wide spectrum
of estuarine species and could disclose species-specific differences
in toxicity and temperature responses. In terms of model verifi-
cation, data collected at a site such as Morgantown are essential
for another reason. Morgantown is situated at the interface region
where fresh and salt waters mix, and where freshwater run-off and
estuarine dynamics may cause large shifts in salinity within short
periods of time. Concurrent changes in the concentration of water
constituents may affect the initial oxidant demand of the cooling
water and alter decay properties of chlorine-induced oxidants.
Both the biological factors outlined above and the chemical factors
emphasized here could affect model parameters (A and B in Eq. 7-1)
and indicate the need for an estuarine fouling control model.
53
-------
An intermediate salinity zone with salinity values varying
between 10 and 20 ppt. A region could be selected which
would be representative of both a marine and an estuarSe
environment in terms of biofouling potential. Dose-response
data from such an environment would be most desirable for
model calibration and verification since experience in Great
Britain has shown that continuous low-level application of
chlorine in such an environment provides an efficacious bio-
fouling control methodology for once-through cooling systms.
t^n^^f '^relatively high amounts of bromine
to 40 ppm) . Both biological and non-biological factors of
rtnVlr°Tnt'C°Uld af£ect nodel Parameters The relative
mportance of species -specific effects could be examined by
calibrating the basic model with dose-response data Sllected
at a site where a broad spectrum of marin? biota and communities
is represented. The relatively high amounts of bnadneTSJSt
^•f°ntMSt-t0 th! tWS Previous en™nments) couS^fSSt
modify chlorine-induced oxidant formation and decay, thGs affect
ing the oxidant term of the model. Comparison of model calcu-
lations and empirical data could reveal the need for the formu-
validity of the ""del will be determined by its utility in
-
54
-------
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60
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APPENDIX A
OXIDANT DECAY IN CHLORINATED AND CHLORDBROMINATED
ESTUARINE CCOLING WATER
Contents
•s.
Aqueous Chemistry of C12 and BrCl in Low-Salinity Cooling Water
Test Procedures
C12 and BrCl-Induced Oxidant Decay Patterns
Factors Affecting Oxidant Decay Rates
Effects of Anmonia and Salinity on C12- and BrCl-Induced Oxidant Decay
A-l
-------
OXIDANT DECAY IN CHLORINATED AND CHLOROBRCMINATED
ESTUARINE COOLING WATER
AQUEOUS CHEMISTRY OF C12 AND BrCl IN LOW-SALINITY COOLING WATER
correlate the formation and decay of halogen derivative^wUh a££S Sd
salinity concentrations, in estuarine water. Please note that STof Se
conclusions reached are preliminary. Detailed test procedures and raw data
on water quality and oxidant decay are given for further
The inorganic forms of dissolved C12 and BrCl that may occur under the
cany follows: g ^™8 ** field investigations «n be
Chlorine
C12 + H20 -> HC1 + HOC1 (hypochlorous acid)
HOC1 -» H+ + OCT Chypochlorite ion)
HOC1 + NH3 -+ H20 + NH2C1 (monochloramine)
NH2C1 + HOC1 -+ H20 + NHC12 (dichloramine)
NHC12 + HOC1 -> • H20 + NCI 3 (trichloramine)
Bromine Chloride
BrCl + H20
HOBr
HOBr + NH3
NH2Br + HOBr
NHBr2 •*• HOBr
HC1 + HOBr (hypobromous acid)
H+ + OBr" (hypobromite ion)
H20 + NH2Br Cmonobromamine)
H20 + NHBr2 (dibromamine)
H20 + NBr3 (tribromamine)
"free
chlorine"
"combined
chlorine"
"free
bromine"
"combined
bromine"
A-2
-------
These reactions do not include organic derivatives and other forms of oxidized
halogen such as halite, halate, or perhalate (X02", XO;, XO; whereX reSS-
sents Cl or Br) . Moreover, near neutral pH, C12 and BrCl do not exisTS the
unhydrolyzed form. Therefore, we will proceed under the simplifying as^mp
tion that the forms of halogen in our study were either "free" or^om
bmed" as defined above Furthermore, since the concentration of ammonia
in the water exceeded that of oxidized halogen in most cases durinHhis
study we will assume that the most prevalent forms of oxidized halogen
were the mono- and dihalamines (see also White, 1972*).
CO-H ^^I1116 water ?f about 5 Parts per thousand (ppt) salinity (a typical
salinity at our experimental site) contains about 10 parts per million (ppm)
i (Culkin> 19^- The following reactionfor the oxidatSn of
^ equilibrium constant of 4 x 10$ (Cotton and Wilkinson,
^ * 10^ liter/-le'
HOC1 + Br" = HOBr + Cl" (A-l)
At this salinity, with the Br" concentration much larger than that of HOC1
(> 0.5 ppm) added during chlorination, it follows that there should be a
50% conversion of HOC1 to HOBr about every 2 seconds near pH 7.5 (an aver-
age pH at the experimental site) .
However, there are competing reactions which may prevent a quantitative
conversion of oxidant from chlorine to bromine forms. Weil and Morris (19491
nave described the kinetics of monochloramine formation:
HOC1 + NH3 = NH2C1 + H20 . (A- 2)
Their data indicate that, under conditions like those found in cooling water
at the experimental site (pH 7 to 7.5; total ammonia and total oxidized
halogen concentrations in the micromolar range; ammonia concentration greater
than [TOXJ), the half -life of free chlorine (HOC1 + OC1") is less than 3 seconds.
Since reactions (A-l) and (A- 2) proceed with approximately equal rapidity,
it is not possible to determine with any confidence which reaction will pre-
dominate.
Monochloramine could in turn be converted to monobromamine in estuarine
water via the reaction:
NH2C1 + Br" = NH2Br + Cl" . (A- 3)
We do not know the kinetics of this reaction, but it is known that iodide
(I") is not quantitatively oxidized by combined chlorine at pH values above
4.5 (APHA, 1975). Since iodide oxidation should proceed more easily than
For literature cited in this appendix, see List of References included
in the main body of this report.
A-3
-------
bromide oxidation it may be that combined chlorine is stable in the Dre-
sence of bromide in the pH range of natural waters. P
Eppley et al. (1976), using a semiquantitative technique, showed that
considerable amounts of bromine were formed upon chlorination of ™awater
However, their conditions do not necessarily apply to Morgan?own ££
SS& at*toTS™to™> the **er ^ ^ss skli£ {and theSfiSThas^ss
bromide) and contains more ammonia. Wackenhuth and Levine (19741 observed
that adding BrCl to saline cooling water with high ammonia content resulted
in lower oxidant levels in discharged water than did adding C12 resulted
of ™t °ur Study " arcperometric back-titration
fPAD? at S 4 d^/fr? S?tas?ium iodide CKD and phenylarsine oxide
IPADJ at pH 4 -- detects total dissolved oxidant without discriminating be-
S^°rin\0r Omne °r amDng the various forms of each oxidized halogen
meretore, we have reported our results in terms of microequivalents
" ' ^ °nly ^^ -
een n T 'i -oe.t
between C12- and BrCl- treated solutions is to observe a difference in the de-
cay characteristics between the induced oxidants. Although this is a
£JS^aiT WaI-« examininS ^at are probably very complex chemical
interactions, differences in decay characteristics do imply differences in
the chemical speciation (all other decay- affect ing parameters being equal)
and the environmental benefits of BrCl versus C12 can be inferred from such
air ferences .
TEST PROCEDURES
Data for the characterization of TOX decay were obtained by one of the
following test procedures.
1) Two gallons of halogenated water were collected in a bucket at a
cooling water circulating pump. At predetermined intervals, 500-
ml aliquots were transferred to bottles containing KI, PAD, and
acetate buffer. This process essentially preserved the aliquot
so that a later back-titration with I2 yielded the TOX concen-
tration at the time the aliquot was "pickled."
This procedure was used to quantify TOX decay in 14 cases where
BrCl was the added halogen and in 21 cases where C12 was used.
The same plastic bucket was used for all decay studies after
being thoroughly cleaned and soaked overnight in a concentrated
chlorine solution. The concentration of TOX was varied by changing
the feed rate of halogen to cooling water.
2) A highly concentrated solution was obtained from the BrCl injection
line, diluted with cooling water, and decay-monitored as in (1) above.
Eight decay curves were obtained.
As a point of reference, it should be noted that 1 yeq/Ji TOX is equivalent
to 35.5 parts per billion (ppb) C12 or 57.7 ppb BrCl.
A-4
-------
3) Since plumbing problems precluded the collection of concentrated
C12 solutions from an injection line, commercial bleach was used
as a C12 source with a technique similar to (2) above to obtain
six C12 decay curves.
4) None of the above procedures yielded a value for a TOX concentration
at time zero. Therefore, in three cases, identical volumes from a
single cooling water source were spiked with identical aliquots of
Ca(OCl)2 solution. One of the water samples contained the pickling
reagents prior to the Ca(OCl)2 addition while the other samples
were pickled at various times after that addition.
These procedures yielded the most useful decay data; the relation-
ship between TOX concentration and time was well-defined, and solution con-
ditions did not vary during a decay period. To obtain a relationship be-
tween TOX level and location, TOX decay was also observed by monitoring con-
centrations along the flow of halogenated cooling water as it moved through
the intake conduits, the condenser, and down the discharge canal. However,
this information was not as useful as "bucket data" in comparing halogens
because (1) the relationship between time and location was not precise, and
(2) in passing through the cooling system, TOX can be lost via the oxidation
of fouling material on condenser surfaces.
C12- AND BrCl-INDUCED OXIDANT DECAY PATTERNS
Figure A-l shows the decay of TOX observed when Ca(OCl)2 was added
to estuarine cooling water; the fourth procedure above was used so that
the TOX concentration at zero time was known. This figure illustrates the
pattern which was routinely observed regardless of whether C12 or BrCl was
the added halogen. Initially, there was a very fast decay during which al-
most 50% of the TOX was lost during the first 30 seconds after halogen addi-
tion. Next, there was a fast decay which extended for 10 to 15 minutes;
and finally, there was a period during which decay was so slow that often no
difference could be seen between TOX levels at 30 and 60 minutes. In the few
cases where TOX decay was followed beyond 60 minutes, the observed con-
centration change with time usually proved to be very small.
The second and third decay phases were always in evidence. The very
fast initial decay was observed only when the fourth test procedure was used.
However, comparisons of calculated TOX levels at the point of halogen injec-
tion with levels observed at the circulating pumps indicated that approxi-
mately 50% of both BrCl- and C12-derived TOX was lost within about 30 seconds
of halogen introduction to cooling water.
Figure A-2 is a transformation of Figure A-l where the logarithm of
TOX concentration is plotted against time. This plot would be a single
straight line if decay were ideal first-order in accordance with the equation:
• = -k [TOX] . (A-4)
dt
A-5
-------
14-
12
16 20 24 28 32 36 40 44 48 52 56 60
TIME (min)
Figure A-l. Time-dependent decay of TOX for Ca(OCl)2 added to estuarine water This
curve is representative of all TOX decay patterns observed during this
-------
>.
1
0 4 8 12 16 20 24
28 32 36 40
TIME(min)
44 48 52 56 60
Figure A-2. Semi-logarithmic transformation of Figure A-1.
-------
are *hree separate lines corresponding to the three
d [TOX] , . f a
at k f10^ (A-5)
TO
c^-K ?St initial decaX is not consistent with any model which de-
vaa reactions wiuch are much faster than those acco uSLg fo? sJSeqSeS! oecay.
The decay after the initial 30 seconds is characteristic onlv of TOX
in estuarine water and has been fitted to a two-phase qSJifiS^order^ model
SSST^ ^ fr0m 2™* °'5 to 1 ^e "P <^1° " 15 SSSef*1'
i a^r f^ S^^TTOX^^^^^
-^riT^^^
to depend on TOX concentrations. However, this slow phafe has not
been very well quantified; it is described by only four fsometimes
ts over a 5°"minute period> ^ r2
*»,« inabi6 ^c1 ?ummarizes all decay data in terms of ki (decay constant for
Colfftcient, ^T f™\dec*y\™* ** (decay constant for the-sSw^ec^.
S!t S ? detemLnatlon (r2) are given for the k2 values to indicate
Sfo ^-6 ValUeS ^Te,n0t always wel1 de^ed. The raw data upon which these
calculations are based are included as Table A- 5.
FACTORS AFFECTING OXIDANT DECAY RATES
Can-be sefn.fr°m Fig"1"6 A-3, where all derived kj constants are
?flr dates^f dete™i*ation, there is a range of decay con-
hal?gens. Therefore, before conparing decay constants be-
!© en5 neCSSSaiy to account for the variation in decay rate
First, it should be noted that the fitting of the observations to
J f^5t-°rder decay roodel does not imply that decay rate is determined solely
by TOX concentration. In general, there are two groups of cooling water
A- 8
-------
Salinity Range (ppt) 4.5 to 5.8
' Region j '
• CI2 derived TOX
o BrCI derived TOX
D TOX >16^ieq./l
o
o
8
0
00
7.2 to 8.9
.20
.16
.12
.08 r •
.04
00* ' ' ' J ' ' ' J ' ' ' j ' ' ' J. I I I^I-l-J-i-l
6.0 to 6.6 0.6-4.1 9.1-9.6
o
o
o
13 17 21 25 29, 2 6 10 14 18 | 14 18 22 26
V
JULY
30 2
I
AUG
SEPT
6 10
OCT
151719
NOV
Figure A-3.
First-order decay constants, kj, plotted against their date of determination
Constants within box have been excluded from overall discussion of decay
See text for meaning of Regions I-V.
-------
Table A-l. SUNMARY OF TOX DECAY DATA CALCULATED
FOR A QUASI-FIRST ORDER MDDEL
Explanation of Columns (left to right)
Run* Position of a single decay determination within temporal
sequence of all determinations. These numbers^fald
m locating raw decay data in Table A-5.
Date/Time Self-explanatory
[T°X]l SSsf50St51°nCentrati?n *° fU ^6 deCay mode1' ExcePt for
except for some cases where the precision is 2 o
to tne lower •v'^inm^i? +••:•«._..*«j —
f to [TOX]
Tp/ [POX] lfel«t point of fast decay and first point
k2(r2) ??o?T c?]^t?lt for XTslow decay and r2 for correlation of In
LTOX] with time. No constant was calculated if less than
tour data points were available.
[TOX] 60 The TOX concentration at 60 + 10 minutes. (One hour after
halogen addition, this 10-minute variation has no signifi-
cant effect on TOX concentration.)
C, S (Ppt) Water quality parameters at time of cooling water collection
02, pH (measured automatically)
[NH3] Ammonia concentration (+ 71) measured within one hour of
cooling water collection (Soloranzo, 1969)
Proc' *" 4- " stated
A-10
-------
Table A-l (continued). SUMMARY OF TOX DECAY DATA
CALCULATED FOR A QUASI-FIRST ORDER MDDEL
Run #
1
2
3
4
5
6
7
8
9
17
20
22
23
25
26
29
32
Date /Time
13/0940
13/1150
13/1345
14/0950
14/1230
14/1405
15/0855
15/1115
22/0930
AUGUST
6/1150
20/1310
SEPTEMBER
15/1300
16/1350
17/1630
23/1230
24/1525
29/1635
[TOXjj
Oieq /t)
4.79
5.97
6.14
10. 37
10.39
9.72
5.49
6.87
7.63
4.48
6.82
4.34
4.82
3.72
67.2
18.1
6.85
1 ii • i.
kl
(min"
0.097
0.078
0.097
0.074
0.088
0.093
0.082
0.098
0.097
0.085
0.140
0.199
0.186
0.209
0.025
0.051
0.123
HALOGEN ADDED: Chlorine
Tp/fTOX
14/1.32
6/3.97
12/2.06
17/3.01
12/3.80
12/3. 38
13/1.94
11/2.42
17/1.61
18/0.99
16/0.76
9/0. 68
9/0. 79
8/0.65
12/50.3
8/12.1
9/2. 20
k2 .1 (r2)
(min )
0. 006 (0. 99)
0.011 (0. 86)
0.019 (0. 94)
0.014 (0. 91)
0.010 (1. 00)
0.018 (0.96)
0.012 (0.76)
0.010 (0.74)
0.025 (0.98)
0.017 (0.89)
0.052 (0.99)
0.008 (0.99)
0.010 (0.86)
0.026 (0.97)
[T°x]60
(H eq/J)
0.96
1.04
1.15
1.32
1.55
1.55
1.01
0.90
0.96
0.65
0.23
0.28
0.08
35.1
6.5
0.62
Temp.
<°C)
25.0
25.0
25.0
24.5
25.0
25.5
24.5
24.0
26.0
26.0
24.5
23.0
23.0
23.5
22.0
22.5
21.0
Salinity
(PPM
4.8
4.5
4.4
5. 1
5. 1
4.9
4.8
4.5
5.7
4.5
8.9
8.4
7.8
7.2
8. 1
7.4
6.0
°2
(Ppm)
3.0
3.6
4.0
3. 3
3.6
3.7
3.2
4.7
1.6
1.4
1.8
4. 1
4.0
4.7
3.1
3.5
4.0
PH
6.9
7.0
7.1
7.0
7.0
7.0
6.9
6.7
6.9
7.0
7.7
7.6
7.7
7.7
7.7
7.8
7.7
NH3
((iM/l)
10.2
7.6
6.5
11.8
9.2
15.1
9.3
9.0
7.5
3.7
4. 5
3.2
3.4
3.8
6.6
Proc.
1
1
1
1
1
1
1
1
1
1
1
1
1
1
3
3
1
-------
Table A-l (continued). SUMMARY OF TOX DECAY DATA
CALCULATED FOR A QUASI-FIRST ORDER MDDEL
NJ
Run (if
33
36
38
40
41
42
43
44
46
49
50
51
52
Date /Time
•
OCTOBER
4/1025
7/1140
7/1555
7/1910
9/1045
9/1210
11/1115
11/1230
14/1005
14/1435
NOVEMBER
15/1415
16/1200
19/1230
HALOGEN ADDED: Chlorine
[TOXjj
-t" • •" ' -.—...
5.32
60.9
26.0
7.94
5.27
6.31
16.59
4.85
6.73
7.01
3.15
7.97
7.77
* Ammonia added
Temp, highcjr than ambi
water taken from discha
_
(min'1)
: —
0.134
0.107
0.050
0.042
0.105
0.059
0.028
0. 036
0.050
0.041
0.084
0.101
0.085
nt since
ge canal
= ====
14/0.99
11/19.8
9/17.5
10/5. 38
16/1.13
11/3.52
16/10.73
13/3.10
15/3.30
14/4. 17
9/1.55
12/2.23
16/2. 00
^2 fp '
(min'1)
= =====
0.015 (0.94)
0.017(0.95)
0.009(0.95)
0.006 (0.95)
0.007(0.97)
0.011(0.99)
0.006(0.93)
0.008(0.88)
0.006(0. 94)
= - —
0.48
8.3
10.1
3.94
6.68
2.23
2.20
3.07
1.21
fc" i i I—
j Temp.
- -
20.0
20.0
20.0
19.5
19.5
19.5
19.0
19.0
18.0
18.0
18.0+
17.5+
1
1 Salinity
(PPt)
6.4
6.2
6. 3
7. 1
6.5
6.4
0.9
0.6
4.1
3.8
9.1
9.6
°2
(ppm)
4.2
4.2
4.0
„
„
„
,2
:;
1
PH
7.5
7.6
7.6
7.6
7.4
7.5
7.4
7.6
7.6
7.7
-_
NH3
: •-
12 8
5 8
6 7
4 2
4O
UO
UA
> 100*
nf.
Proc
= .:
i
-3
4
4
4
-------
Table A-l (continued). SUMMARY OF TOX DECAY DATA
CALCULATED FOR A QUASI-FIRST ORDER MODEL
>
OJ
Run #
1 =
10
11
12
13
14
15
16
18
19
21
24
27
28
30
31
i •
Date/ Time
: =====
HIT v
27/1443
28/1030
28/1315
AUGUST
5/1040
5/1240
5/1420
6/1040
14/1100
19/1630
20/1445
SEPTEMBER
17/1520
23/1535
24/1310
29/1330
29/1430
[TOXjj
ftieq It)
•
1.38
2.17
1.38
1.58
4.59
4.85
3.44
3.58
4.08
4.17
5.63
67.3
49.7
36.6
6.85
I,.
-j k HALOGEN ADDED: Bromine Chloride
kl
(min"1)
: =====
0.138
0.138
0.142
0.158
0.167
0.110
0.109
0.128
0. 103
0.126
0. 190
0.052
0.038
0.072
0.143
Tp/f TOX ]
=====
13/0.25
11/0.51
11/0.31
11/0.28
11/0.76
15/0.90
16/0.62
16/0.48
19/0.65
k2 , (r2)
(min )
======
0.11 (0.42)
D.017 (0.82)
0.027 (0.97)
3.039 (0.79)
D.009 (0.55)
3.013 (0.79)
>. 014 (0.93)
"
16/0.65 k). 006 (0.97)
11/0.93 B.018 (0.98)
6/49. 3
13/31.4
10/18.5
9/1.80 JC
0.008 (0.88)
).010 (0.98)
>.017 (0.87)
1.012 (0.95)
,
[TOX]6fl
-------
>
i
Table A-l (continued). SUMMARY OF TOX DECAY DATA
CALCULATED FOR A QUASI-FIRST ORDER MODEL
HALOGEN ADDED:
0.020 (0.95)
O.OZ3(0.97)
-------
characteristics which may affect the decay of TOX. The first group is re-
presented by water quality parameters, such as PH, ammonia concentration*
tv temperatures, and possibly salinity, that can affect the speciation
"°™r
by
An example of the first type of effect would be a change in decay rate of
Cl2-induced oxidants due to the presence of NH3 or a change in pH. These para-
^??rSM^ri S T \l * P^ti1:i°ning °£ dissolved chlorine among the forms HOC1,
OC1 , NH2C1, and other chloramines. For a given oxidizable substrate, the rate
of its oxidation (i e. , the rate of chlorine decay) may depend on the kinetics
of its reaction with each particular form of oxidized chlorine. As indicated
above, in saline waters there is the possibility that the number of oxidant
species will be expanded due to the presence of Br~ . A second-order effect
of salinity is the change in speciation among different forms of a single halo-
gen due to the effect of ionic strength and complex formation on the thermodyna-
mic activities of each individual species. This latter effect has recently
been quantified by Sugam and Helz (1976) for the HOC1, OC1' partitioning.
Regardless of the speciation of dissolved oxidant, no decay will .occur
unless something is oxidized. The most prevalent oxidizable substrate is
water. Thermodynamically, the reactions of both dissolved C12 and BrCl with
H20 to produce oxygen are favored. In practice, .however, these reactions are
extremely slow in the absence of ultraviolet (U.V.) irradiation. Using the
fourth test procedure, we observed no decay of C12 in distilled water. Since
sunlight does not enter the cooling water system, halogenated water samples
used for decay studies were normally not exposed to sunlight. When subsamples
of estuarine water were divided so that half were exposed to sunlight (in a
bucket) and half were not, there was no difference in TOX levels 1 hour after
halogenation. This lack of a sunlight effect may be due to the natural turbi-
dity of estuarine water.
While we have no measurements of oxidizable substances in cooling water,
they must be present for TOX decay to occur. Eppley et al. (1976) observed
that chlorine decay in natural seawater could be slowed by either the removal
of participate material or treatment of the water by U. V. irradiation
prior to chlorination, i.e., removing or destroying oxidizable substrate.
Consequently, it follows that TOX decay rate depends on both the quantity and
quality of the oxidizable substrate.
A second avenue of TOX disappearance is via the formation of halogenated
organic molecules. However, while this aspect of halogenation may be of prime
importance in assessing environmental hazards of the process , it is negligible
with regard to the loss of TOX. Jolley et al. (1975) observed that less than
31 of the C12 added to two cooling water solutions became incorporated into
stable chlorinated organics.
Given that TOX decay depends on both TOX speciation and quality and
quantity of oxidizable substrate [S] , the overall decay of TOX may be written
«•»*•»•
as:
The term "ammonia" in this report is intended to include both forms of
dissolved inorganic ammonia (NH3 and MHO.
A-15
-------
where, for each combination of TOX species (i) and substrate (i) there is a
kinetic expression of order (at + bj) with a decay constant kr .'
The speciation of dissolved halogen can, in theory, be calculated from
thermodynamic data (properly corrected for effects of temperature and ionic
strength) so that one can write:
[TOX]. = g. [TOX] . (A-7)
with Zgi - i. The gj_ values are functions of thermodynamic data and solution
conditions. For a sunple solution of C12 in pure water at pH 7, for instance,
8HOC1 = °'73» and SOGI- = °-27> as calculated from White (1972):
K = l [Hl _ 1Q-7.43
HOC1
The data obtained in this study are consistent with TOX decay being
first order in [TOX]. Thus, if we use Eq. A- 7 and set a; = 1 for all i
Eq. A-6 becomes: '
Comparing Eqs. A- 8 and A- 4 yields:
ij gi [S]jJ CA-9)
where the left-hand member (k) is a quasi- first order constant derived
from the observed decay data. It follows from Eq. A-9 that a series
of decay determinations can yield the same empirical k value only if g-
and [S] remain constant, i.e., only if oxidant speciation and quantity
and quality of oxidizable substrate remain constant. Furthermore, the
observed decay will follow first-order kinetics only if [S] is large
relative to [TOX] so that loss of [S] is insignificant.
The observed decays should be functions of oxidant speciation and [S] .
However, two observations suggest that the relationship is not simple. First,
a change from fast to slow decay within 10 to 15 minutes after halogenation
was consistently observed; and secondly, when a water sample was re-halogenated
about 1 hour following an initial halogenation, the decay curve obtained upon
rehalogenation was identical in form to the one observed initially. Thus,
the transition to the slow phase did not occur because all the available, easily
oxidizable substrate was exhausted. Conceivably, after 10 to 15 minutes of con-
tact, the supply of certain oxidant species was exhausted due to reaction with
oxidizable substrate. Upon the readdition of a "fresh" supply of C12 or BrCl,
A- 16
-------
of such oxidant species could again permit rapid oxidation
Implicit in this line of reasoning are two assumptions: first, with low-
level chlorination or chlorobromination, only a small portion of the available
oxidizable substrate is indeed oxidized; second, the C12- and BrCl-induced
oxidants are indeed reduced to Cl' and Br~. If, instead they were transformed
^nS"? °*ldlzed£orm ?f ^gai such as C10I or BrO;, which cannot bfde?™
mined by the analytical method, the observed decay would not be due to conlump
™? ™ ?£ldan 7 TdlZable substances ^ Doling water. Since we have ind?-
*?™on!c. at some undetectable form of oxidant may be forming in saline solu-
tions (Figure 4-1), we feel reasonably certain that decay in the estuarine
system was due to an actual reduction (acceptance of electrons) of TOX.
EFFECTS OF ANMONIA AND SALINITY ON C12- AND BrCl-INDUCED OXIDANT DECAY
We have investigated the differences between the decay of the Cl,-induced
2L JS"3??*? °5ldants ^ estuarine water. We have also attempted to deter-
mine the effects of water quality parameters on these decay rates
th* fS^fJ " ? S relatlvely rapid decay, defined as klf occurring during
the first 15 minutes of contact between the biocide and estuarine water (The
initial decay occurring during the first 30 seconds of contact is not consid-
ered in this discussion; since the first sample for oxidant analysis was usually
tS VP™™?!f-3^Se?°!?dS a£t!r mixing Of the biocide ^ cooling wter, often
the very rapid initial decay phase was completed.) The relatively slow decays
(k2) occurring after the first 15 minutes are less important in continuous low-
level chlorination or chlorobromination because the slow-phase oxidant loss
is minimal with this mode of application. Thus, characterization of this phase
is not crucial to determining either minimum dosage required for biofouline
control or differences between the decay of C12- and BrCl-derived oxidants?
The Fast-Decay Phase
For the present analysis, we have eliminated from consideration those
k! values determined from runs where the first measured TOX concentration was
greater than 16 ueqA (Runs 26-30, 35-38, 43; cf. Table A-l). Except for Run
43, the initial halogen concentration in all these cases exceeded the ammonia
concentration. Therefore, instead of the amine species that are the major
dissolved oxidants at lower halogen concentrations (White, 1972; Johnson and
Overby, 1971), noncombined halogen species (hypohalite ion and hypohalous acid)
were probably present. Since such differences in speciation may have resulted
in anomalous decay constants, these runs were deleted from the data set. We
also eliminated Runs 40 and 42 because alkaline commercial bleach was used as
a chlorine source. As pointed out by Carpenter and Macalady (1976), chlorite
ion may form during alkaline storage, and we do not know how chlorite reacts
with the reagents used for oxidant analysis. Runs 46 and 47 were eliminated
because ammonia was added in abnormally high concentrations, and Runs 4, 9,
13' .» 15» 19» 40» 45» 50> 51» and 52 were not used because ammonia and/or
salinity information was incomplete.
A-17
-------
The runs included in the present analysis (10 BrCl and the 17 ci,1 arP
recorded in Table A-2; representative runs are plotted in Figure A-4 From
the relationship shown in Figure A-4 and a review of the k, values recorded
in Table A-2, it is evident that the decay constants for both biociSs vary
over a relatively wide range. To determine to what extent measured water
quality parameters could be responsible for the observed spread in decay con
stants, we tested the correlation of kx values with water temperature dis-
solved oxygen salinity, PH, and ammonia. We also tested the correlation of
k: values with initial measured oxidant concentration since the existence of
such a relationship would violate the assumption of first-order decay
° *et*rmination Cr2) for these correlations, recorded
in ae
S aloltttTto^yTf £
« ^
by any of the six parameters tested individually S1g*i±icantly affected
Because the C12 -decay constant showed NH3 and salinity deoendencv a
prediction equation for chlorine decay was calculated £ multiSe iSr
regression, using the Table A-2 data sets. We obtained
= -0.0508 + (0.004+ 0.002) [NH3] - (0.018 ±0.004) [S] (A-10)
With « ^flession coefficient of 0.9051 and a standard error of estimate
of ± 0.0230.
This relationship suggests that, at relatively low salinity values, the
rate of oxidant decay will decrease with increasing ammonia concentrations.
Conversely, at constant ammonia values, an increase in salinity will tend
to speed up the rate of oxidant decay.
As pointed out earlier, these differences in decay may reflect differ-
ences in oxidant speciation occurring upon chlorine injection. At high
ammonia concentrations, the reaction between HOC1 and NH3 (Eq. A-2) may pre-
dominate over the reaction between HOC1 and Br~ (Eq. A-l). The formation
of the relatively stable chloramines would then account for the rather slow
decay observed under these conditions. At high salinity values, the Br~ would
compete more effectively for the limited amount of HOC1 than NH3, thus allow-
ing the formation of the more reactive hypobromous acid or bromamines.
Alternatively, one may postulate that the quality and quantity of oxidiz-
able substrates in the cooling water change with salinity. At relatively high
salinity values, therefore, the amounts of reduced organic and inorganic con-
stituents, which react more rapidly with available oxidants, would be higher
than in the fresher cooling water. Our data do not allow selection between
the alternative hypotheses.
Obviously, the applicability of expression (A-10) for predicting
chlorine-induced oxidant decay in estuarine water is limited to a certain
range of salinity and ammonia values. The boundary conditions can be esti-
mated on the basis of the decay characteristics observed with BrCl.
A-18
-------
BROMINE CHLORIDE
0.97
0.97
0.98
0.95
10
20 30
Time (min)
40
50
60
CHLORINE
Run 7 ,
kj ' -0.082 min l
k2 = -0.010 min"1
Run 20 T
kj = -0.140 min l .
k,=-0.025 min"1 r2
= 0.96
= 1.00
= 0.94
0.98
Run 32 , 9
kj * -0.123 min l r = 0.
k, = -0.026 min r - 0.
.98
r^ = 0.97
Time (min)
Figure A-4.
Representative examples of the rapid (k,) and slow (k2) decay of Cl2-and BrCl-induced
oxidants in estuarine cooling water.
-------
Table A-2. ANMONIA AND SALINITY EFFECTS ON THE DECAY
OF BrCl- AND C12-INDUCED OXIDANTS
(Data from Table A-l)
Run [TOX]1
Number neq/ i
CHLORINE
1 4. 79
2 5.97
3 6.14
5 10.39
6 9.72
7 5.49
8 6.87
17 4.48
20 6.82
22 4. 34
23 4.82
25 3.72
32 6.85
33 5.32
41 5.27
44 4. 85
49 7.01
Average
Standard Deviation (+)
ppb
170
212
218
369
345
195
244
159
242
154
171
132
243
189
187
172
249
Salinity
ppt
4.8
4.5
4.4
5.1
4.9
4.8
4.5
4.5
8.9
8.4
7.8
7.2
6.0
6.4
6.5
0.9
3.8
MS
( (i M/ i )
10.2
7.6
6. 5
11.8
9.2
15. 1
9.3
9.0
7.5
3.7
4.5
3.2
6.6
12.8
4.2
11.8
13.6
Obs.
-0.097
-0.078
-0.097
-0.088
-0.093
-0.082
-0.098
-0.085
-0.140
-0.199
-0.186
-0.209
-0. 123
-0.134
-0. 105
-0.028
-0.036
-0. 1105
0.0507
kj (min~ )
Pred.
-0.0924
-0.0980
-0.1009
-0.0910
-0.0983
-0.0718
-0.0909
-0.0922
-0. 1758
-0.1829
-0. 1690
-0.1639
-0.1286
-0.1096
-0. 1474
-0.1360
-0.0518
-0.1105
0. 0458
Pred/Obs.
0.95
1.26
1.04
1.03
1.06
0.88
0.93
1.08
1.26
0.92
0.91
0.78
1.05
0.82
1.40
0.49
1.44
1.018
0.234
k - (min )
Obs.
-0.006
-0.011
-0.019
-0.014
-0.010
-0.018
-0.010
-0.025
-0.017
-0.052
-0.026
-0.015
-0.006
-0.006
-0.016
0.012
BROMINE CHLORIDE
11 2.17
12 1.38
16 3.44
18 3. 58
21 4.17
24 5.63
31 6.85
34 3. 94
39 9. 15
48 7. 18
Average
Standard Deviation (+)
125
80
198
206
240
308
394
227
526
413
5.5
5.3
4.5
7.6
8.7
7.2
6.0
6.4
7.1
3.4
10.5
7.6
9.0
10.9
6.5
3.4
6.6
10.7
6.7
13.6
-0.139
-0.072
-0.109
-0.163
-0.126
-0.190
-0.143
-0. 134
-0.100
-0.092
-0. 127
0.035
-0.1180
-0.1184
-0.1087
-0. 1400
-0. 1554
-0.1421
-0. 1266
-0. 1274
-0.1384
-0.0931
-0.1268
0.0182
0.85
1.64
1.00
0.86
1.23
0.75
0.89
0.95
1. 38
1.01
1.056
0.278
-0.017
-0.027
-0.014
-0.006
-O.M8
-0.012
-0. 026
-0.023
-0.0179
0.0072
A- 20
-------
Table A-3. COEFFICIENTS OF DETERMINATION (r2)*
BETWEEN kj AND VARIOUS WATER QUALITY PARAMETERS
FOR BrCl- AND C12-DERIVED OXIDANT
(Runs included in analysis are recorded in Table A-2)
Parameter
S (ppt)
NH3-N (fiM/ a)
PH
T (°C)
O2 (ppm)
[TOXJ,,^*,
*
V2 _ n 2Xy - 2
r2
0.76
0.50
0.35
0.03
0.00
0.43
Ix Zy
uniorine
No. Samples
17
17
16
17
17
17
Bromine
r2 No
0.23
0.20
0. 15
0.01
0.13
0.00
Chloride
. Samples
10
10
10
10
10
10
n(n-l)SxSy
A-21
-------
If we assume that the postulated speciation hypothesis is correct, and
that the ratio of the concentrations of Br" and NH3 determines the distribution
of added oxidant between chloramine and bromamine constituents of the cooling
water (reactions A-l over A-2), the maximum rate of C12-induced oxidant decay
that can be attained would be equal to the rate of BrCl-induced oxidant decay.
This latter rate can be estimated on the basis of the 10 data sets* recorded
in Table A-2. The available data allow the calculation of the following rela-
tionship:
-0.0686+ (0.001 ±0.005) [NH3] -(0.009+0.011) [S] (A-ll)
The multiple regression coefficient is 0.5188; the standard error of the esti-
mate ±0.0339. This expression indicates that the average decay rate is
-0.13 min' , and that the decay of bromine chloride-induced oxidant is rela-
tively insensitive to variations in salinity and NH3 concentrations.
Substitution of the average BrCl decay value in Eq. A-10 allows calcu-
lation of salinity and ammonia values at which C12-induced and BrCl-induced
oxidant decay rates are equal. Figure A-5 illustrates the results of these
calculations. The relationship depicted indicates that, for a given ammonia
concentration in the cooling water, the rate of oxidant decay, and therefore
the advantage of BrCl over C12 in limiting environmental impacts of biocide
use, will depend on salinity.
The Slow-Decay Phase
As seen from Table A-4, no strong relationship exists between ki and k2,
nor does the exclusion of data (discussed above") from our analysis of ki con-
stants greatly affect the average k2 values. Most important, unlike ki values,
there is no significant (at the 0.10 level) difference between slow decay
constants for BrCl" and C12-derived oxidant.
A crucial unanswered question is the reason for the change in decay
rate observed 10 to 15 minutes after halogenation. We have already shown
that the change cannot be due to a decrease in available oxidizable substrate:
upon rehalogenation of a 1-hour old sample of halogenated estuarine water,
the pattern of very fast initial decay followed by periods quantifiable by
k! and k2 constants is repeated. The change in decay rate must, therefore,
be due to a change in the speciation of TOX, but we have no ready explanation
for the observed behavior.
Ten data sets are insufficient for estimating three coefficients. There-
fore, the derived relationship must be considered as tentative.
A-22
-------
no
CO
8 16
Figure A-5. Anmonia and salinity effects on decay constants of BrCl- and
and G.2-induced oxidants.
A-23
-------
TABLE A-4. SLOW DECAY CONSTANT, k2, AND ITS RELATIONSHIP TO ka
(Data from Table A-2)
C12 BrCl
Ave k2 (rnin"1) -0.016 -0.018
S.D. k2 0.012 0.007
(ki x k2) r2 0.57 0.24
Number of samples 13 8
Potential Environmental Benefits of BrCl for Biofouling Control
While rigorous determination of factors affecting halogen decay re-
mains to be done, the quasi-first order decay models discussed earlier
can be used to estimate the relative advantage of replacing C12 with BrCl
in power plant applications. Consider a system where two streams from a
single source of low salinity cooling water are halogenated with equimolar
amounts of C12 and BrCl. Within the initial 30 seconds, 50% of tS TOX in
• V^vT5 1S 1?sJ'and» durinS the next 10 minutes, the C12- and BrCl-de-
rived TOX decays with first order constants of -0.11 rain-1 and -0 13 min'1
respectively (these constants are the overall averages fromTable A-2)? '
After 10 minutes, the ratio of TOX levels can be described by:
[TOX]^
e-0.20
™a ,Thus» t*16 TOX concentration of the BrCl- treated stream will be about
201 less than that of the C12 -treated stream. If the first-order decay were
to last for 15 minutes instead of 10 minutes, the oxidant concentration of
the chlorobrominated stream would be 30% less than that of the chlorinated
stream.
If BrCl and C12 were dosed on an equal weight, rather than equimolar
basis, the above ratios for [TOX]BrC1 to [TOX]cl2 would be 0.50 for a 10-'
minute decay and 0.45 for a 15-minute decay. Since equal weights of the two
biocides are comparable in antifouling effectiveness (see Chapters 5 and 6) ,
it is reasonable to expect a 50 to 60% decrease in effluent oxidant levels
when C12 is replaced with BrCl. Whether or not this decrease is significant
in lowering any toxic effect of such treated effluents will depend on the
absolute value of discharged TOX levels and the toxicity response of the biota
of the receiving water.
A-24
-------
Table A-5. SIMMY OF RAW HALOGEN
DECAY DATA
Key to Table Headings
1) Run number identified as #X. These numbers are the same as those
used in Tables A-l and A-2.
2) Type of halogen: C12 and BrCl
3) The first number in parentheses (1 through 4) identifies test proce-
dures as described in this Appendix under 'Test Procedures."
4) The subsequent numbers in parentheses, separated by "/," are month
and day, respectively.
Key to Columns
The first column is the biocide contact time in minutes; the second
column is the oxidant concentration in yeq/£ observed at the specified
time.
A-25
-------
# 1
C12. (1
1.0
2.0
4.0
6.0
14.0
29.0
49.0
68.0
(7/13)
4.79
4. 11
3. 55
3. 10
1.32
1.24
1.07
0.96
# 2
C12. (1) (7/13)
0.75
2.0
3.5
6.0
16.0
41.0
62.0
5.97
5.21
4.62
3.97
__
1.21
1.04
# 3
C12. (1) (7/13)
0. 50
1.75
3.0
4.75
12.0
30.0
48.0
64.0
6. 14
5.46
5.04
4. 39
2.06
1. 38
1.21
1.15
f 4
C12, (1) (7/14)
0.75
1.92
3.33
5.67
17.0
32.0
61.0
10.37
8.87
8.25
7.18
3.01
2.28
1.35
* 5
C12, (1) (7/14)
0.67
1.75
2.83
4.42
12.0
32.0
47.0
60.0
10.39
9.27
8.48
8.56
3.80
2.23
1.66
1.55
# 6
C12, (1) (7/14)
0.75
1.75
2.83
4.67
12.0
28.0
49.0
67.0
9.72
8.65
7.97
7.01
3.38
2.23
1.69
1.55
A-26
-------
# 7
C12, (1
0.67
2.83
7.08
9.50
12.75
27.0
43.0
67.0
(7/15)
5.49
4.79
3. 38
3.10
1.94
1.52
1.30
1.01
# 8
C12, (1) (7/15)
0.58
1.50
5.83
7.50
11.0
29.0
47.0
66.0
6.87
6.17
4. 17
3.72
2.42
1.52 •
1.10
0.90
# 9
C12, (1) (7/22)
0. 50
2.0
9.0
17.0
36. 0
39.0
59.0
64.0
7.63
6. 14
2. 11
1.61
0.99
1. 15
0.82
0.96
I 10
BrCl, (1) (7/27)
0.67
1.50
2.67
4.50
13.0
39.0
54.0
59.0
1.38
1.21
1.10
0.99
0.25
0.31
0.20
0. 14
# 11
BrCl, (l)(7/28)
0.42
1.08
1.92
3.67
11.0
26.0
42.0
53.0
59.0
2.17
2.03
1.83
1.66
0.51
0.56
0.31
0.25
0.28
f 12
BrCl. (l)(7/28)
0.42
1.25
2.42
4.58
11.0
24.0
35.0
62.0
1.38
1.30
1. 13
1.07
0.31
0.25
0.20
0.08
A-27
-------
# 13
BrCl, (1) (8/5)
0.50
1.50
3.0
5.0
11.0
18.0
33.0
54.0
1. 58
1. 15
1. 18
0.93
0.28
0.23
0.06
0.06
# 14
BrCl, (1) (8/5)
0. 58
1.75
3.58
6. 50
11.0
20.0
35.0
49.0
60.0
4. 59
3.77
2.99
2.17
0.76
0.54
0.39
0.45
0.45
i 15
BrCl. (1) (8/5)
0.42
1.58
4.08
9.0
15.0
25.0
39.0
55.0
4.85
4.00
3.04
2.03
0.90
0.62
0.54
0.51
* 16
BrCl, (1) (8/6)
0.42
1.50
4.17
8.42
15.75
26.50
48.0
63.0
3.44
2.90
2.08
1.41
0.62
0.45
0.34
0.31
f 17
C12, (1) (8/6)
0.50
1.50
4.08
9.17
18.0
27.0
42.0
59.0
.4.48
3.86
2.87
2.00
0.99
0.79
0.62
0.65
# 18
BrCl, (1)(8/14)
0.33
2.42
4.17
9.45
16.00
22.50
3.58
2.34
1.86
0.79
0.48
0.42
A-28
-------
# 19
BrCl, (1) (8/19)
0.50
1.50
3. 50
7.50
12.45
19.00
26.25
51.0
4.08
3. 35
2.68
1.97
0.85
0.65
0.37
0.34
f 20
C12, (1) (8/20)
0.42
2.00
4.25
7. 58
10.67
15.50
22. 33
35.17
59.0
68.0
6.82
3.92
2.48
1.77
1.04
0.76
0.56
0.45
0.23
0.25
(if 21
BrCl, (1) (8/20)
0.42
2.00
4.00
7.50
10.33
15. 50
22.42
34.0
60.0
4. 17
3. 35
2.56
2.03
0.99
0.65
0.51
0.48
0.42
* 22
C12. (1) (9/15)
0.58
1.67
3.25
6.75
9.08
13.50
24.50
44.17
90.0
4.34
3.13
2.25
1.55
0.68
0.65
0.34
0.31
0.17
f 23
C12. (1) (9/16)
0.42
1.33
2.92
7.17
9.17
19.17
30.0
4.82
3.58
2.51
1.52
0.79
0.48
0.37
* 24
BrCl. (1) (9/17)
0.50
1.42
3.33
4.92
7. 17
11.0
23.75
36.33
60.0
5.63
4.54
3.24
2.62
1.21
0.93
0.62
0.56
0.37
A-29
-------
1 25
C12, (1) (9/17)
0.42
1.33
3.50
6.25
8.25
14.75
26.0
47.0
3.72
2.68
1. 55
1.13
0.65
0.39
0.25
0.08
I 26
C12, (3) (9/23)
0.33
1.25
2.42
5.37
7.70
11.62
24.33
38.33
55.50
114. 50
263.33
67.2
63.8
62.1
57.7
55.0
50.3
46.1
41.0
35.1
29.0
19.0
# 27
BrCl, (2) (9/23)
0.25
1. 13
2.42
5.92
8.83
14.75
18.42
28.00
37.50
54.87
105.75
67.3
60.9
55.9
49.3
_.
__
36.8
32.8
29.6
25.8
20.3
# 28
BrCl, (2) (9/24)
0.33
1.25
2.75
5.67
8.30
12.50
20.22
30.72
47.77
63.17
49.7
46.8
43.2
39.8
34.2
31.4
28.4
24.6
21.0
19.0
# 29
C12. (3) (9/24)
0.33
1.33
2.92
6.17
8.30
14. 50
26.33
43.33
66.75
18.1
17.4
15.2
13.4
12. 1
10.3
8.1
6.9
6.5
f 30
BrCl, (2) (9/29)
0.50
1.33
2.92
7.03
9.58
14.80
24.83
43.25
79.95
36.6
30.2
25.2
18.9
18.5
12.3
9.0
7.0
4.8
A-30
-------
#31
BrCl,(2) (9/29)
0.92
2.08
3.50
6.75
8.83
13.08
27.92
44. 17
73.67
6.85
5.52
4.34
2.99
1.80
1.24
0.73
0.54
0.42
# 32
C12, (1) (9/29)
0.67
1. 58
3. 50
7.42
9.42
13.83
26.83
49.92
6.85
5.83
4.59
3.10
2.20
1.63
0.99
0.62
# 33
C12, (1) (10/4)
0.42
1.25
3.25
6.83
9.00
. 13.58
22.25
33.50
61.25
5.32
4.79
3.89
2.70
1.41
0.99
0.85
0.62
0.48
# 34
BrCl, (1) (10/5)
0.42
1.33
3.17
6.58
9.00
14.00
26.08
56.00
3.94
3.30
2.59
1.72
0.70
0.62
0.42
0.45
#35
BrCl, (2) (10/7)
0.33
1.17
2.83
5.58
7.67
12.67
25.25
32.83
45.25
59.33
267.0
.58.2
52.1
44.9
35.9
30.2
23.7
«,_ ••
14.0
10.8
9.7
5.0
# 36
C12, (3) (10/7)
0.50
1.09
2.25
3.75
4.92
10.92
18.92
35.42
46.67
61.17
183.0
60.9
54.1
49.4
• *
32.7
19.8
15.5
10.8
9.5
8.3
4.5
A-31
-------
1 37
BrCl. (2) (10/7)
0.33
1.17
2.33
5.17
8.08
12.75 ,
24.00
32.25
49.75
67.58
164.0
22.1
19.4
17.5
15.6
11.2
8.6
6.0
4.5
3.3
2.4
U7
# 38
C12. (3) (10/7)
0.33
1.17
2.33
3.58
5.25
8.83
15.83
25.50
41.67
67.0
130.0
26.0
25.3
23.3
23.0
18.9
17.5
15. 1
13.6
11.7
10.1
8.3
f 39
BrCl, (2) (10/7)
0. 50
1.67
3.17
6. 17
8. 50
14.50
24.75
36.00
51.08
62.83
9.15
7.52
6.28
4.65
3.35
2.25
1.46
1.13
0.85
0.76
f 40
C12, (3) (10/7)
0.58
1.42
2.67
4.58
6.25
10.25
20.75
30.00
41.67
60.75
7.94
7.55
7. 15
6.73
5.80
5.38
4.73
4.56
4.34
3.94
f 41
C12. (1) (10/9)
0.42
1.58
3.50
6.42
8.67
12.67
15.83
26.00
40.25
5.27
4.68
3.86
3.01
1.89
1.38
1.13
0.82
0.76
#42
C12, (3) (10/9)
0.58
1.50
2.67
4.50
5.50
10.58
20.67
29.83
44.83
6.31
5.94
5.61
5.30
4.51
3.52
3.18
3.01
2.79
A-32
-------
#43
C12, (1
0.42
1.42
4.00
8.00
11.00
16.42
25.58
34.50
44.50
60.00
(10/11)
16.59
15.94
14,68
13.32
11.69
10.73
9.41
8.56
7.72
6.68
#44
C12, (1) (10/11
0.42
1.58
3.67
7. 16
9.75
13.33
22.50
32.25
64.00
4.85
4.56
4.25
3.86
3.27
3.10
2.73
2.56
2.23
#45
BrCl, (1) (10/11
0. 45
1.42
3.67
7.67
10. 00
14.25
25.92
35.67
55.42
6.03
5.58
4.82
3.97
3.13
2.42
1.69
1.07
0.70
1 46
C12. (1) (10/14)
0.58
1.67
4.33
8.00
10.75
15.42
27.58
42.42
62.17
6.73
6.28
5.49
4.59
3.83
3.30
2.68
2.34
2.20
#47
BrCl (1) (10/14)
0. 58
1.67
4.25
8.00
10.42
15.92
29.42
44.00
63.00
8.28
7.63.
6.45
5.07
3.66
2.85
1.44
0.87
0.68
#48
BrCl (1) (10/14)
0.42
1.50
3.92
7.33
9.75
14.08
23.67
42.00
66.75
7. 18
6.42
5. 18
3.97
2.85
2.06
1.15
0.85
0.54
A-33
-------
# 49
C12, (1) (10/14)
0.42
1.42
3.83
7.33
9.67
13.58
22.67
34.42
50.92
60.00
7.01
6.56
5.92
5.38
4.51
4,17
3.69
3.41
3.18
3.07
# 50
C12, (4)(11/15)
0.00
0.75
0.92
1.75
3.08
9.33
9.04
3.15
3.32
2.70
2.14
1.55
51
C12, (4) (11/16)
0.00
0.67
1.50
4.42
12.00
13.24
7.97
5.61
3.69
2.23
# 52
C12. (4) (11/19)
0.00
0.75
1.67
3.58
5.75
9.83
15.83
16.00
21.42
30.67
60.17
13.63
7.77
6.23
5.07
4.25
3.10
2.00
1.94
2.06
1.44
1.21
A-34
-------
APPENDIX B
SUMMARY OF BrCl AND C12 DOSE RATES (kg/day) AND TOX
LEVELS (yeqA) AT THREE BIOFOULING SIMULATORS
DURING TRIALS I AND II
Contents
Trial I (11 August - 26 August)
Trial II (10 September - 24 September)
B-l
-------
SUMMARY OF BrCl AND C12 DOSAGES (kg/day) AT THR]
BIOFOULING SIMULATORS DURING TRIALS I AND II
TRIAL I (11 August - 26 August)
During this period, dose rates varied as follows:
Time Interval
Date/Time Date/Time
11/0900
12/0050
12/0730
16/1800
19/1630
24/0900
11/0900
12/0050
12/0730
14/1130
15/2200
16/0500
12/0050
12/0730
16/1800
19/1630
24/0900
26/0900
12/0050
12/0730
14/1130
15/2200
16/0500
26/0900*
Applied Dosage (kg/day)
Unit #1 CBrCl)
1360
OFF
1360
OFF or between 725
and 1040
1360
725 to 1090
Unit
(C12)
910
OFF
910
OFF
910
910
*For this period, only two of three circulating pumps were in operation;
thus, dose is equivalent to one of 1360 kg/day for a flow of three pumps.
Each pump delivers 10.4mVsec.
B-2
-------
rnv ,Within discreet regions of the total test period, the August
TOX levels are summarized as follows: ^jgust
ate/Time Date/Time
Unit #1 (BrCl)
H
11/0900 12/0050 |3.9 0.4
|224)*k
3.4
T7T
12/ 0050 12/ 0730 JBrCl + C^ OFF
12/0730 14/1130
14/1130 15/2300
15/2300 16/1800
13.4
Dd96)
16/1800 19/1630 JBrC]
D
19/1630 24/0900 B 4. 0
J(230)
24/ 0900 26/ 0900
11/0900 12/0050
12/0050 12/0730
12/0730 14/1130
14/1130 15/2ZOO
15/2200 16/0500
16/0500 26/0900+
1.9
(109)
0.2
OFF
0.3
0.3
3.0
375
or flu
3.6
47?
1.7
77?
(4)
(17)
ctuatii
(5)
(5)
2.6
(150)
2.2
(127)
V
2.6
(150)
1.3
(75)
0.4
0.2
0.2
0.1
2.3
77Z
1.7
775
2.4
775
1.1
T77
(4)
(17)
(5)
(5)
1.8
(104)
1.5
(186)
0.9
(52)
. 4
(81)'
1.1
(63)
1.7
(98)
1.5
(86)
0.4
0.2
0.2
0.2
0.1
0.1
0.2
1.5
777
1. 1
T75
0.7
T7T
1.2
T-r
1.1
T7Z
1.6
T75
1.4
T77
(4)
(11)
(3)
(4)
(4)
(4)
(5)
Unit #2 (Clj)
-------
TRIAL II CIO September - 24 September)
«. oi S^f th^s Period> dose rates for each halogen remained constant
S^&sp a ss sss s s.rf s as GsSi
simulators on each unit are summarized as follows: ^uiouimg
Circulator
Water box
Discharge
Unit 1 (BrCl)
Mean S.D. ^'^
Samples
1.1 0.1 14
(63)*
0.9 0.1 14
(52)
1.0 0.1 15
(58)
Unit 2 (C12)
Mean S.D.
5.0 0.3
(178)*
3.3 0.3
(117)
1.6 0.2
( 59)
No. of
Samples
18
17
17
*Values in parentheses are biocide concentrations in ppb.
B-4
-------
APPENDIX C
FOULING ASSAY INFORMATION
Contents
Organic and Inorganic Dry Weight Content of Fouling Material Accumulated
on Glass Panels
Statistical Evaluation of Biofouling in Presence and Absence of Biocides
C-l
-------
FOULING ASSAY INFORMATION
ORGANIC AND INORGANIC DRY WEIGHT CONTENT OF FOULING MATERIAL ACCUMULATED
ON GLASS PANELS
The organic and inorganic dry weight contents of fouling material
accumulating with time of exposure on 116-ra2 glass panels are presented.
The data are recorded in Tables C-l, C-2, C-3, andare givenbytime (day)
o± sampling, biocide type, and station location.
C-2'
-------
Table C-l. MEAN TOTAL DRY WEIGHT, ORGANIC WEIGHT, AND INORGANIC
WEIGHT AT DAYS 3, 6, 9, 12, AND 15 FOR THE 15-DAY TESTS CONDUCTED
DURING THE FIRST STUDY 11 AUGUST 1976 TO 26 AUGUST 1976
*\
(Weight Values Represent 116-cm Glass Panel Area)
Test Conditions
Stut ion
Location Type
limhaymunt
Circulator CI2
Condenser Cl^
Ilischarge ctz
Circulator BrCl
Condenser RrCl
Discharge BrCl
Biocide
Mean Conc.a Total
(lieq/lk (ppb) Weight (wg)
0.0 0 11. 39(13. 589)b
3.1 178.Z5 16.13(14.851)
1.8 103.50 22.36(110.099)
1.4 80.50 29.82(18.409)
Days of Fouling Exposure
Day 3 (14 August
Organic
n c Weight (ing)
8 3.79(11.158)
no data
no data
no data
8 3.79(10.682)
4 4.39(i0.97H)
7 5.11(12.038)
1976)
Inorganic
n Weighting)
8 7.60(13.439)
8 12.34(14.275)
4 17.97(19.175)
7 24.71(16.457)
n
8
8
4
7
Mean concentration Tor trial period
SlS.D.
Number of samples
-------
Table C-l (continued)
Test Conditions
Station
Location
limbayment
Circulator
Condenser
Discharge
Ci rculator
Condenser
Discharge
Type
Cl,
CU
C12
BrCl
BrCl
BrCl
Biocide
Mean Cone. Total
(ueq/1) (ppb) Weightdng)
°.° 0 78.96(110.471)
3.1 178.25 19.47(15.490)
1.8 103.50 49.29(125.593)
1.4 80.50 63.34(128.273)
Days of Fouling Exposure
Day 6 (17 August 1976)
Organic
n Weight(mc)
8 14.03(11.855)
no data
no data
no data
8 4.57(11.033)
4 7.48(12.836)
8 11.58(13.660)
Inorganic
n Weight(mg) n
8 64.93(110.242) 8
8 14.90(14.545) 8«
4 41.81(122.793) 4
8 51.76(124.759) 8
Muan concentration for IS days
-------
Table C-l (continued)
Test Conditions
Days of Fouling Exposure
Day 9 (20 August
Station Mean Conc.a Total Organic
Location Type (ueq/l) (ppb) Weight(mg) n WeiKht(»K)
HMhaywent 0.0
Circulator c\2
Condenser Cl,
o 2
en Discharge C^
Circulator BrCl 3.1
Condenser BrCl 1.8
Discharge BrCl 1.4
0 224.98(t26.S99) 8 36.7S(i4 .025)
no data
no data
no data
178.25 42.95(110.120) 8 7.12(tl.312)
103.50 95.28(117.319) 4 13.70(±1 . 338)
80.50 267.12(153.039) 8 39. 66(16 .196)
1976)
Inorganic
n Weight(mg) n
8 188.23(122.704) 8
8 35.83(i9.395) 8
4 81.58(±17.379) 4
8 227.46(147.019) 8
concentration for IS days
-------
Table C-l (continued)
Test Conditions
Station
Location
linhayMent
Circulator
' Condenser
ON
Discharge
Circulator
Condenser
Discharge
Type
C12
C12
ci2
BrCl
BrCl
BrCl
Biocide
Mean Cone. Total
(Meq/I) (ppb) Wcifiht(mfi)
0.0 0 716.75(1166.149)
3.1 178.25 51.44(±11.381)
1.8 103.50 151.58(145.578)
1.4 80.50 806.85(1187.589)
Days of Foul ing Exposure
Day 12 (23 August
Organic
n WeiKht(m.Q)
8 112.43(129.517)
no data
no data
no data
8 40.57(18.230)
4 22.38(18.357)
8 141.57(131.645)
1976)
Inorganic
n Weij>ht(me)
8 604.32(1136.831)
8 lol. 87(14.877)
4 129. 20(437. U20)
8 665.28(1156.938)
n
8
8
4
8
''Mean concentration for IS days
-------
Table C-l (continued)
n •
Test Conditions Days of Fouling Exposure
Blocidc Day 15 (26 Aucust 19761
Station
Location
IJNbayaent
Circulator
Condenser
Discharge
Circulator
Condenser
Discharge
Type
ci2
CI2
C12
BrCl
BrCl
BrCl
Mean Cone.
to'*!/1) Weight(wg) n Weight(nc) n
°-° ° 1318.26(1223.394) 8 206.14(133.300) 8
no data
no data
no data
3.1 178.25 67.63(122.255) 8 10.42(12.772) 8
1.8 103.50 215.35(160.085) 4 29.62(16.123) 4
1.4 80.501588.50(1640.376) B 230.53(182.062) 8
Weiglit(iDfi) n
1112.12(1191.107) 8
57.21(119.573) 8
185.73(153.980) 4
1357.97(1560.704) 8
'Mean concentration for 15 days.
-------
Table C-2. MEAN TOTAL DRY WEIGHT, ORGANIC WEIGHT AND INORGANIC
WEIGHT AT DAYS 3, 6, AND 9 FOR THE 9-DAY TESTS CONDUCTED
DURING THE FIRST STUDY 17 AUGUST 1976 TO 26 AUGUST 1976
(Weight Values Represent 116-on2 Glass Panel Area)
n
GO
Test Conditions
Station
l.ocu t i on Type
liwbuyMcnt
Circulator Cl,
Condenser C12
Discharge Cl_,
Circulator BrCl
Condenser BrCl
discharge BrCl
Blocide
Days of Foul
Day 3 (20
Mean Cone. *
(peq/1) (ppb)
0.0
7.3
4.9
1.9
2.9
2.0
1.5
0 130
259.15 24
173.95 21
67.45 58
166.75 29
115.00 31
86.25 125
Total
Weighing)
.39(±22. 158)b
.12(±10.189)
.83(13.663)
.73(111.610)
.47(16.076)
.74(15.023)
.25(126.495)
ing Exposure
August 1976)
Organic
nc Weight (ing) n
5
10
5
10
5
4
5
20.11(13
3.93(11
4.37(10
8.40(11
4.58(11
5.45(10
20.52(14
.057)
.367)
.972)
.543)
.629)
.879)
.412)
5
10
5
10
5
4
5
Inorganic
Weight(me)
110
20
17
SO
24
26
104
.28(119.370)
.19(18.
.46(14.
.33(110
.89(15.
.29(14.
.73(122
995)
025)
.204)
284)
339)
.233)
n
5
10
5
10
5
4
5
Mean concentration for trial period
b± 1 S.D.
Number of samples
-------
Table C-2 (continued)
Test Conditions
Station
Location Type
liwbuymunt
Circulator C12
Condenser C12
Discharge Cl,
-------
Table C-2 (continued)
Test Conditions
Days of Fouline Exnosure
Day 9 f26 August 107*)
Station
Location Type
limbayment
Circulator C12
Condenser C12
Discharge C12
Circulator BrCl
Condenser BrCl
Discharge BrCl
Mean Cone.
(Meq/l) (ppb)
0.0
7.3
4.9
1.9
2.9
2.0
1.5
0 808
259.15 91
173.95 91
67.45 571
166.75 52
115.00 118
86.25 1005
Total
Wei6ht(«fi)
.46(1247.854)
.00(135.
.71(120.
.10(1177
355)
542)
.274)
.77(17.533)
.39(174.
.49(1278
920)
.485)
n
S
10
5
10
5
4
S
Organic
Weight(mg) n
125
12
12
70
8
16
142
.56(140.980) S
.30(14.
.81(12.
.52(118
780) 10
807) 5
.838)10
.59(10.833) 5
.28(110
.93(133
.847) 4
.641) S
Inorganic
Weight(me) »
682.90(1206.996)
78
78
500
44
102
862
.70(130.834)
.90(117.943)
.58(1159.334)
.18(16.823)
.11(164.255)
.56(1244.866)
5
10
5
10
S
4
S
concentration for 9 days.
-------
Table C-3. MEAN TOTAL DRY WEIGHT, ORGANIC WEIGHT AND INORGANIC
WEIGHT AT DAYS 3, 6, AND 9 FOR THE 9-DAY TESTS AND DAYS 3, 6, 9, 12,
AND 15 FOR THE 15-DAY TESTS CONDUCTED DURING THE SECOND
STUDY 10 SEPTEMBER 1976 TO 25 SEPTEMBER 1976
(Weight Values Represent 116-cm2 Glass Panel Area)
Test Conditions
Station
Location Type
tiwbayMcnt
Circulator C12
Condenser C12
Discharge C12
Circulator BrCl
Condenser BrCl
Discharge B'Cl
Diocides
Mean Cone.
(ueci/M
0.0
5.3
3.3
1.6
1.1
0.9
1.0
Days
Day 3
a
(Ppb)
0
188.15
117.15
56.80
63.25
51.75
57.50
Total
Weifiht(mK)
13. 33(i3. 160)b
15.05(11.175)
8.88(11.165)
28.25(110.144)
16.80(15.151)
13.62(13.263)
41.32(118.098)
nc
8
8
4
8
8
4
8
of Fouling Exposure
(13 September
Organic
WeiCht(mR)
3.14(10.785)
3.03(10.468)
2.31(10.292)
5.35(12.447)
3.44(10.880)
3.10(11.463)
6.00(11.032)
1976)
n
8
8
4
8
8
4
8
Inorganic
Weiglit(ng)
10.19(12.609)
12.02(11.309)
6.57(11.291)
22.90(17.869)
13.36(14.376)
10.52(12.165)
35.32(117.880)
n
8
8
4
8
8
4
8
*Mean concentration for trial periods
b+lS.D.
£
Number of samples
-------
Table C-3 (continued)
n
— ,.
Test Conditions
Station
Location Type
liuibaymcnt
Circulator CI2
Condenser C12
Discharge C1-,
Circulator Brd
Condenser BrCl
Discharge BrCl
Diocideu
Mean Cone.
(Meq/1) (ppb)
0.0 0
5.3 188.15
3.3 117.15
1.6 56.80
1.1 63.25
0. 9 51. 75
1.0 57.50
Total
Weight(mc)
42.33(110.006)
18.64(14.763)
20.35(12.605)
33.65(18.303)
29.78(17.375)
28.32(113.204)
56.70(116.035)
Days of Foulinc Exnosure
Day
n
8
8
4
8
8
4
8
6 (16 September 19761
Organic
WeiKlit(mjj)
7.60(11.051)
3.57(10.999)
4.29(11.081)
5.81(11.356)
5.58(11.317)
4.75(11.939)
10.64(13.282)
n
8
8
4
8
8
4
8
Inorganic
Weiolit(me)
34.73(19.195)
15.07(13.951)
16.06(11.535)
27.84(17.129)
24.20(16.123)
23.57(111.274)
46.06(112.879)
8
8
4
8
8
4
8
concentration for IS days.
-------
Table C-3 (continued)
n
Test Conditions
Station
Location Typ*
limbayMCitt
Circulator C12
Condenser C12
Discharge C12
Circulator BrCl
Condenser BrCl
Discharge BrCl
Biocide*
Days of Fouling Exposure
Day 9 (19 September 1976)
Mean Cone?
(Heq/l> (ppb)
0.0
5.3
3.3
1.6
1.1
0.9
1.0
0
188.15
117.15
56.80
63.25
51.75
57.50
Total
Weight(«K)
76.77(118
28.56(114
20.39(114
38.50(16.
31.85(17.
53.77(16.
95.68(126
.652)
.143)
.603)
972)
425)
580)
.254)
n
8
8
4
8
8
4
8
Organic
Weight(mR)
14.27(12.
4.97(11.
5.84(14.
7.24(11.
6.13(il.
9.22(13.
21.74(111
945)
531)
798)
313)
287)
757)
.669)
n
8
8
4
8
8
4
8
Inorganic
Weight (m«)
62.50(115
23.59(112
14.55(110
31.26(15.
25.72(i6.
44.55(15.
73.94(128
.782)
.787)
.744)
714)
218)
515)
.075)
n
8
8
4
8
8
4
8
''MUUII concentration for 15 days.
-------
Table C-3 (continued)
Test Conditions
Station
Location Type
liMbayncnt
Circulator C12
£ Condenser Cl^
Discharge Cl_
Circulator BrCl
Condenser BrCl
Discharge BrCl
Biocide*
Mean Cone.' Totaj
JlifflM) (ppy Weight(m^)
°-° ° 169.75(150.225)
5.3 188.15 25.50(112.347)
3'3 117-15 22.39(18.904)
1.6 56.80 77.99(116.504)
1.0 57.50 97.78(125.091)
Days of Fouling Exposure
Day 12 (22 September 1976)
Organic Inorganic
n Weight(mg) n Weichtr.K.1
8 28.09(16.347) 8
8 3.08(11.497) 8
< 2.04(11.349) 4
8 9.55(12.933) 8
no data
no data
8 17.59(13.852) 8
1*^ \ Of ^
141.66(144.048) 8
22.42(110.983) 8
20.35(18.765) 4-
68.44(113.770) 8
80.19(121.554) 8
''Moan concentration for 15 days.
-------
Table C-3 (continued)
Test Conditions
Days of Fouling Exposure
Biocides Day IS (25 September 1976)
Station
Location Type
limhaywent
Circulator CU
n *•
t-> Condenser cl?
in '
Discharge C12
Circulator BrCl
Condenser BrCl
Discharge BrCl
Mean Cone.* Total
(Mcq/1) (ppb) Weight (rag)
°-° ° 297.95(147.455)
5.3 188.15 33.22(122.549)
3.3 117.15 21.07(15.891)
1.6 56.80 86.52(120.003)
1.0 57.50 159.37(126.977)
Organic
n Weiuht(mg)
8 50.03(162.02)
8 6.31(12.242)
4 5.02(11.741)
8 15.09(12.685)
no data
no data
8 29.98(13.686)
Inorganic
n Wei gh t(ms)
8 247.92(141.966)
8 26.91(120.520)
4 16.05(14.445)
8 71.43(117.380)
8 129.39(123.509)
n
8
8
4
8
8
4Mcua concentration for 15 days.
-------
EVALUATION OF BIOFOULING IN PRESENCE AND ABSENCE
period yed tfoSlacJ11 ^ £!" V" Second
of variance (ANOVA). Before toANW?.?.^ ^ hierarchal analysis
. ere toANW.. ays
greater than the smallest one ' therefole sev^^ " I** C3Se was several fold
transformation, square root transforStion I?r l trans£o™tions (e.g., log
variance. "^ " honoen
, soron r l
variance. The log trans forma STfS S d ^ "^ " hono«eni«
fore, an data Werge
ee of the three study variables
bers nested within station! and C4) rSliclSe ±? 4 ( 'K^' (3) foulinS cham-
1
sa
.
chambers could only be run in duplicate kTSL /?, ?St f^7 Period' fouling
Anaiytical Procedures, "
weight foraliS9ttsh0^STe t^^-E-^. and inorganic
.
^?^d sSS?2^^^^^
o.e *?* sfatij"-b>'-day interactions.
of the station ?actor was Der?^^?^ ^ ^A f°r ^ e£fect at each le^
stations, Tukey's test Winlr ^ * S^lflcant effect was found between
yC Se tes™** tO deteCt si^i«it differences
C-16
-------
Significant differences were found for station effects at each level of
the day factor in all studies. The specific differences by day among the BrCl
^2. and «ference stations for all three variables are summarized iS Tables
C-5 to C-7. Table C-5 is a summary of Tukey's test (Winer, 1971) of the among
mean station comparisons of all BrCl stations at days 3 6 9 12 anri ?<; ft£
the 15-day trial conducted between 11 August 1976 anl 26 August 976
of the among mean station comparisons of all BrCl and C12 stations for
r an 2 stations for tte
T^eSCCrfsT™^17fAtr5 ,1976 *°* 5? ^UgUSt 19?6' *S Presented L?able^6
Table C-7 is a summary of the 9-day and 15-day trials conducted during September
Significant differences were also found for day effects at each level of
the station factor in all studies. The specific differences by station among
the days for all three variables are summarized in Tables C-8 to C-10 Table
C-8 is a summary of Tukey's test (Winer, 1971) of the among mean day comparisons
?Q7f ^f A°n f°r1S!^15'day trial conducted during the first study (11 August
1976 and 26 August 1976) . A summary of the among mean day comparisons of each
station for the 9-day trials conducted between 17 August 1976 and 26 August 1976
is presented in Table C-9. Table C-10 is a summary of the 9-day and IsSay
trials conducted during September 1976.
Literature Cited
Bancroft, T.A. Topics in Intermediate Statistical Research. Iowa State
Univ. Press, Ames. 129 p. 1968
Winer, B.J. Statistical Principles in Experimental Design. iMcGraw Hill,
New York. 387 p. 1971
C-17
-------
Table C-4. STATION IDENTIFICATION CODES FOR TABLES
Station s*a «•*.... TJ . ,.
Identification Code
Erabayment (reference) _ . „
crab - R
Unit I circulator-BrCl
v-i r * fi
Unit I condenser-BrCl
Con-B
Unit I dischargc-BrCl
ui s • B
Unit II circulator-Cl, „. „
*• Lir-C
Unit II condcnser-Cl,
2 Con-C
Unit II discharge-Cl,
2 Dis-C
C-18
-------
Table C-5. SUMMARY OF THE STATISTICAL ANALYSES OF THE
AMONG MEAN STATION COMPARISONS OF ALL BROMINE
CHLORIDE STATIONS AT DAYS 3, 6, 9, 12,AND 15 FOR THE
15-DAY TEST CONDUCTED DURING THE FIRST STUDY
11 AUGUST 1976 TO 26 AUGUST 1976a>b
Station
Emb-R
Cir-B
Con-B
Dis-B
Station
Emb-R
Cir-B
Con-B
Dis-B
Station
Emb-R
Cir-B
Con-B
Dis-B
Emb-R
Day 3 Total Weight
Cir-B
NS
Emb-R
Con-B
*
NS
Day 3 Organic Weight
Cir-B Con-B
NS NS
-- ' NS
Emb-R
Day 3 Inorganic Weight
Cir-B Con-B
NS *
NS
Dis-B
*
*
NS
Dis-B
NS
NS
Dis-B
NS
Concentrations with an * were significantly different at P<0.01;
concentrations with NS were not significantly different at P>0.01
"See TableC-4 for station identification codes.
C-19
-------
Table C-5 (continued)
Station
Cir-B
Con-B
Dis-B
Emb-R
Station
Cir-B
Con-B
Dis-B
Emb-R
Station
Cir-B
Con-B
Dis-B
Emb-R
Day 6 Total Weight
Cir-B Con-B Dis-B
* *
NS
Cir-B
Day 6 Organic Weight
Con-B Dis-B
NS *
NS
Cir-B
Day 6 Inorganic Weight
Con-B Dis-B
* *
NS
Emb-R
*
*
NS
Emb-R
NS
Emb-R
NS
C-20
-------
Table C-5 (continued)
Station
Cir-B
Con-B
Dis-B
Emb-R
Station
Cir-B
Con-B
Dis-B-
Emb-R
Station
Cir-B
Con-B
Emb-R
Dis-B
Cir-B
Day 9 Total Weight
Con-B
Dis-B
*
Day 9 Organic Weight
Cir-B • Con-B Dis-B
* *
Day 9 Inorganic Weight
Cir-B Con-B Emb-R
* *
*
Emb-R
*
*
NS
Emb-R
NS
Dis-B
*
*
NS
C-21
-------
Table C-5 (continued)
Station
Cir-B
Con-B
Emb-R
Dis-B
Station
Cir-B
Con-B
Emb-R
Dis-B
Station
Cir-B
Con-B
Emb-R
Dis-B
Pay 12 Total Weight
Con-B Emb-R
* *
Day 12 Organic Weight
Cir"B Con-B Emb-R
* *
Day 12 Inorganic Weight
Cir'B Con-B Emb-R
* *
Dis-B
*
*
NS
Dis-B
*
*
NS
Dis-B
*
*
NS
C-22
-------
Table C-5 (continued)
Station
Cir-B
Con-B
Emb-R
Dis-B
Station
Cir-B
Con-B
Emb-R
Dis-B
Station
Cir-B
Con-B
Emb-R
Dis-B
Cir-B
Day 15 Total Weight
Con-B
*
Emb-R
Cir-B
Day IS Organic Weight
Con-B Erab-R
Day IS Inorganic Weight
Cir-B Con-B Emb-R
Dis-B
NS
Dis-B
NS
Dis-B
NS
C-23
-------
Table C-6. SUMMARY OF THE STATISTICAL ANALYSES OF THE
AMONG MEAN STATION COMPARISONS OF ALL BROMINE
CHLORIDE AND CHLORINE STATIONS AT DAYS 3, 6, AND
9 FOR THE 9-DAY TEST CONDUCTED DURING THE FIRST
STUDY 17 AUGUST 1976 TO 26 AUGUST 1976a'b
Station
Con-C
Cir-3
Cir-C
Con-B
Dis-C
Dis-B
Erab-R
Con-C
Day 3 Total Weight
Cir-C Cir-B Con-B
NS NS NS
NS NS
NS
Dis-C
*
*
*
NS
._•
Dis-B
*
*
*
*
*
E.r.b
*
*
*
*
*
-R
Day 3 Organic Weight
Station Con-C Cir-C Cir-B
Cir-C -- NS NS
Con-C -- NS
Cir-B
Con-B
Dis-C
Emb-R
Dis-B
Con-B Dis-C Enb-R Dis-3
NS * * *
NS NS * *
NS NS * *
NS * *
* *
NS
--
™*»- "**£ an * were significantly different at P<0.01-
concentrations with NS were not significantly different at P>o!6l
k
See TableC-tfor station identification codes.
C-24
-------
Table C-6 (continued)
Day 3 Inorganic
Station Con-C Cir-C Cir-B
Con-C -- NS • NS
Cir-C -- NS
Cir-B
Con-B
Dis-C
Dis-B
Emb-R
Keight
Con-B Dis-C Dis-B Enb-R
NS * * *
NS * * ..*
NS * * *
* * *
* *
NS
Station
Cir-B
Cir-C
Con-C
Dis-C
Emb-R
Dis-B
Day 6 Total Weight
Cir-B Cir-C Con-C Dis-C
-. * * *
NS *
.. *
Emb-R
*
*
*
NS
Dis-B
*
*
*
'*
NS
C-25
-------
Table C-6 (continued)
Station
Cir-B
Cir-C
Con-C
Dis-C
Emb-R
Dis-B
Station
Cir-B
Cir-C
Con-C
Dis-C
Emb-R
Dis-B
Cir-B
Day 6 Organic Weight
!ir-C
NS
--
Con-C
NS
NS
--
Dis-C
*
*
*
Emb-R
*
*
*
NS
Dis
*
*
*
*
-B
NS
Cir-B
Day 6 Inorganic Weight
Cir-C Con-C Dis-C
* *
Emb-R
Dis-B
NS
*
*
*
*
*
*
NS
NS
C-26
-------
Table C-6 (continued)
Station
Cir-B
Con-C
Cir-C
Con-B
Dis-C
Emb-R
Dis-B
Station
Cir-B
Cir-C
Con-C
Con-B
Dis-C
.Emb-R
Dis-B
Day 9 Total Weight
Cir-B
n.-C Cir=C Con-B Dis-C Emb-R
S NS * * *
NS NS * *
NS * *
* *
NS
.
Dis-B
it
*
*
*
NS
NS
Cir-B
Day 9 Organic Weight
Cir-C Con-C Con-B
NS NS NS
NS NS
NS
Dis-C
Emb-R
*
*
.*
*
NS
Dis-B
NS
C-27
-------
Table C-6 (continued)
Day 9 Inorganic Weight
Station Cir-B Con-C Cir-C Con-B Dis-C Erab-R Dis-B
Cir-B -- NS ' NS * * * *
Con-C -- NS NS * * *
Cir-C -. NS * * *
Con-B .. * * „
Dis'C -- NS NS
Erab-R ..
.\O
Dis-B
C-28
-------
Table C-7. SUMMARY OF THE STATISTICAL ANALYSES OF THE
AMONG MEAN STATION COMPARISONS OF ALL BROMINE
CHLORIDE AND CHLORINE STATIONS AT DAYS 3, 6, AND
9 FOR THE 9-DAY TEST AND DAYS 3, 6, 9, 12, AND 15
FOR THE 15-DAY TEST CONDUCTED DURING THE SECOND
STUDY 10 SEPTEMBER 1976 TO 25 SEPTEMBER 1976a'b
Station Con-C
Con-C
Emb-R
Con-B
Cir-C
Cir-B
Dis-C
Dis-B
Station Con-C
Con-C
Con-B
Cir-C
Emb-R
Cir-B
Dis-C
Dis-B
Day 3 Total Weight
Emb-R Con-B Cir-C
NS NS NS
NS NS
NS
•
Day 3 Organic Weight
Con-B Cir-C Emb-R
NS NS NS
NS NS
NS
--
Cir-B Dis-C Dis-B
NS * *
NS * *
NS * *
NS NS *
NS *
NS
Cir-B Dis-C Dis-3
NS NS *
NS NS NS
NS NS NS
NS NS NS
NS NS
NS
Concentrations with an * were significantly different at P<0.01;
concentrations with NS were not significantly different at P>0.01.
bSeeTableC-4 for station identification codes.
C-29
-------
Table C-7 (continued)
Day 3 Inorganic Weight
Station Con-C Emb-R Con-B
Con-C -- NS NS
Emb-R - -- NS
Con-B
Cir-C
Cir-B
Dis-C
Dis-B
Cir-C Cir-B Dis-C Dis-B
NS NS * *
NS NS * *
NS NS * *
NS NS *
NS *
NS
Station
Cir-C
Con-C
Con-B
Cir-B*
Dis-C
Emb-R
Dis-B
Day 6 Total Weight
Cir-C Con-C
NS
C Con-B Cir-B
NS NS
NS NS
NS
_
Dis-C
NS
NS
NS
NS
--
Emb-R
*
*
NS
NS
NS
Dis-B
*
*
*
NS
NS
NS
C-30
-------
Table C-7 (continued)
Station Cir-C
Cir-C
Con-C
Con-B
Cir-B
Dis-C
Emb-R
Dis-B
Day 6 Organic Weight
Con-C Con-B Cir-B Dis-C
NS NS NS NS
NS NS NS
NS NS
NS
--
Emb-R
NS
NS
NS
NS
NS
--
Dis-B
*
*
*
NS
NS
. NS
— —
Station
Cir-C
Con-C
Con-B
Cir-B
Ois-C
Emb-R
Dis-B
Day 6 Inorganic Weight
Cir-C Con-C Con-B Cir-B Dis-C
NS NS NS NS
NS NS NS
NS NS
NS
Emb-R
*
*
NS
NS
NS
Dis-B
*
*
NS
NS
NS
NS
C-31
-------
Table C-7 (continued)
Station Con-C
Con-C
Cir-C
Cir-B
Dis-C
Con-B
Era'b-R
Ois-B
Station Cir-C
Cir-C
Con-C
Cir-B
Dis-C
Con-B
Emb-R
Day 9 Total Weight
Cir-C Cir-B Dis-C Con-B Emb-R Dis-B
NS NS * * * *
NS NS * * *
NS NS * *
NS NS *
NS NS
NS
_
Day 9 Organic Weight
Con-C Cir-B Dis-C Con-B Emb-R Dis-B
NS NS NS NS * *
NS NS NS * *
NS NS * *
NS NS *
NS *
vc
Dis-B
C-32
-------
Table C-7 (continued)
Day 9 Inorganic Weight
Station Cir-C Con-C Cir-B Dis-C Con-B Emb-R
Cir-C -- NS NS * * *
Con-C -- NS NS NS *
Cir-B -- NS NS *
Dis-C -- NS NS
Con-B -. NS
Emb-R
Dis-B
Dis-B
*
*
*
NS
NS
NS
..
Station
Con-C
Cir-C
Dis-C
Dis-B
Emb-R
Con-C
Day 12 Total Weight
lir-C
NS
--
Dis-C Dis-B
* *
* *
NS
..
Emb-R
*
*
*
*
C-33
-------
Table C-7 (continued)
Day 12 Organic Weight
Station Con-C Cir-C Dis-C
Con-C * *
Cir-C .- *
Dis-C
Dis-B
Emb-R
Day 12 Inorganic Weight
Station Con-C Cir-C Dis-C
Con-C -- NS *
Cir-C -. *
Dis-C
Dis-B
Emb-R
Day IS Total Weight
Station Con-C Cir-C Dis-C
Con-C -- NS *
Cir-C -. *
Dis-C
Dis-B
Emb-R
Dis-B Enb-R
* *
* *
NS *
NS
Dis-B Emb-R
* *
* *
NS *
NS
Dis-B Erab-R
* *
* *
* *
*
C-34
-------
Table C-7 (continued)
Day 15 Organic Weight
Station Con-C Cir-C Dis-C
Con-C -- NS *
Cir-C ' -- *
Dis-C
Dis-B
Emb-R
Dis-B Enb-R
* *
* *
* *
NS
Station
Con-C
Cir-C
Dis-C
Dis-B
Emb-R
Day IS Inorganic Weight
Con-C Cir-C . Dis-C
NS *
*
Dis-B
*
*
*
C-35
-------
Table C-8. SUMMARY OF THE STATISTICAL ANALYSES OF THE
AMONG MEAN DAY COMPARISONS OF EACH STATION FOR THE
15-DAY TESTS CONDUCTED DURING THE FIRST STUDY
11 AUGUST 1976 TO 26 AUGUST 1976a
Day
3
6
9
12
IS
Day
3
6
9
12
15
Day
3
6
9
12
IS
Embayment (Reference) - Total Weight
369 12 IS
* * * *
* * *
* *
*
--
Embayment (Reference) - Organic Weight
3 6 9 • 12 IS
* * * *
* * *
* *
*
'
Embayment (Reference) - Inorganic Weight
3 6 9 12 . 15
* * * *
* * *
* *
*
Days with an * were significantly different at P<0.01; days with
.NS were not significantly different at P>0.01.
C-36
-------
Table C-8 (continued)
Day
3
6
9
12
15
Day
3
6
9
12
15
Day
3
6
9
12
IS
Unit I Circulator (BrCl) - Total Keight
369 12
.. NS * *
* *
NS
'
Unit I Circulator (BrCl) - Organic Weight
369 12
NS * *
* *
NS
--
Unit I Circulator (BrCl) - Inorganic Weight
36 9 12
NS * *
.. * *
NS
--
15
*
*
NS
NS '
--
15
*
*
NS
NS
--
15
*
*
NS
NS
C-37
-------
Table C-8 (continued)
Unit I Condenser (SrCl) - Total Weight
Day 3 6 9 12
3 - - * * *
6 -- * *
9 -- NS
12
IS
Unit I Condenser (BrCl) . Organic Weight
Day 3 6 9 12
3 NS * *
6 -- * *
9 -- NS
1 2
-------
Table C-8 (continued)
Day
3
6
9
12
15
Day
3
6
9
12
15
Day
3
6
9
12
IS
Unit I Discharge (BrCl) - Total Weight
3 69 12
* * *
* *
*
--
Unit I Discharge CBrCl) - Organic Weight
369 12
NS * *
* *
NS
--
Unit I Discharge (BrCl) - Inorganic Weight
3 69 12
* * *
-- « *
- - *
--
is
*
*
*
*
--
IS
*
*
*
NS
15
*
*
*
A
C-39
-------
Table C-9. SUMMARY OF THE STATISTICAL ANALYSES OF THE
AMONG MEAN DAY COMPARISONS OF EACH STATION FOR
9-DAY TESTS CONDUCTED DURING THE FIRST STUDY
17 AUGUST 1976 TO 26 AUGUST 1976a
gmbayment (Reference) - Total Weight
Day 3 6 9
3 -- * *
6 -- *
•9
Embayment (Reference) - Organic Weight
Day 3 6 g
3 -- * *
6 -. *
9
Embayment (Reference) - Inorganic Weight
Day 3 6 9
3 * *
6 .- *
9
Unit I Circulator (BrCl) - Total Weight
Day 3 5 9
3 NS *
6 -- *
9
aDays with an * were significantly different at P <0.01; days with
NS were not significantly different at P>0.01.
C-40
-------
Table C-9 (continued)
Unit I Circulator (BrCl) - Organic Keight
Day 3 69
3 -- NS *
6 NS
9
Unit I Circulator (BrCl) • Inorganic Weight
Day 3 6 9
3 NS *
6 -- *
9 --
Unit I Condenser (BrCl) - Total Weight
Day 3 9
3 -- *
9
Unit I Condenser (BrCl) - Organic Weight
Day 3 9
3 . *
9 ..
Unit I Condenser (BrCl) - Inorganic Weight
Day 3 9
3 -- *
9
C-41
-------
Table C-9 (continued)
Unit I Discharge (BrCl) - Total Weight
Day 3 6 9
3 .. , ' ,
6
9
Unit I Discharge CBrCl) - Organic Weight
Day 3 6 o
3 * *
6 " NS
9
Unit I Discharge (BrCl) - Inorganic Kci?ht
Day 3 6 9
3
6 ...
9
Unit I| Circulator (C12) - Total Weight
Day 3 6 9
3 * *
6 - - NS
9
C-42
-------
Table C-9 (continued)
Unit II Circulator (Cl?) - Organic Weight
Day 36g
3 * *
6 . -- NS
9
Unit II Circulator (C12) - Inorganic Weight
Day 369
3 -- * *
6 -- NS
9
Unit II Condenser (C12) - Total Weight
Day 3 6 9
3 -- * *
6 . -- NS
9
Unit II Condenser (C12) - Organic Weight
Day 369
3 * *
6 • -- NS
9
C-43
-------
Table C-9 (continued)
Unit II Condenser (Cl?) - Inorganic Weight
3 6 9
3
6 " MS
9
Unit II Discharge (C12) - Total Weight
Day 3 6 9
3
6
9
Unit II, Discharge (C12) - Organic Weight
Day 3 6 Q
3
6
9
Unit II Discharge (Cl2) - Inorganic Weight
Day 3 6 9
3 -- *
6 ...".
9
C-44
-------
Table C-10. SUMMARY OF THE STATISTICAL ANALYSES OF THE
AMONG MEAN DAY COMPARISONS OF EACH STATION FOR THE
9-DAY AND 15-DAY TESTS CONDUCTED DURING THE
SECOND STUDY 10 SEPTEMBER 1976 TO
25 SEPTEMBER 1976a
Day
3
6
9
12
IS
Day
3
6
9
12
15
Day
3
6
9
12
15
Embayment (Reference) - Total Weight
369 12
* * *
* *
*
--
Embayment (Reference) - Organic Weight
369 12
* * *
* *
*
--
Embayment (Reference) - Inorganic Weight
3 69 12
* * *
* *
"
•
.
15
*
*
*
*
--
IS
*
*
*
*
--
IS
*
*
It
*
Days with an * were significantly different at P<0.01; days with
NS were not significantly different at P>0.01.
C-45
-------
Table C-10 (continued)
Unit I Circulator (BrCl) - Total Weight
Day 3 6 9
3 * *
6 NS
9
Unit I Circulator (BrCl) • Organic Weight
Day 36g
3 -- NS *
6 NS
9
Unit I Circulator (BrCl) - Inorganic Weight
Da/ 369
3 * *
6 NS
9
Unit I Condenser (BrCl) - Total Weight
Day 3 6 9
3 * *
6 *
9
C-46
-------
Table C-10 (continued)
Unit I Condenser (BrCl) - Organic Weight
Day 3 6 9
3 -- NS *
6 -- NS
9
Unit I Condenser (BrCl) - Inorganic Weight
Day 369
3 * *
6 *
9
Unit I Discharge (BrCl) - Total Weight
Day 36 9 12 IS
3 NS . * * *
6 » * *
9 -- NS *
12 *
IS
C-47
-------
Table C-10 (continued)
Day
3
6
9
12
IS
Day
3
6
12
9
15
Day
3
6
12
' 9
IS
Unit I Discharge (BrCll - Organic Weight
3 6'9 12
NS * *
NS *
NS
Unit I Discharge fBrCl) - Inorcanic Weiaht
3 6 12 9
NS * *
NS *
NS
Unit II Circulator (C12) - Total Weight
3 6 12 9
-- NS NS *
NS NS
NS
--
15
*
*
*
NS
..
15
*
*
*
NS
..
15
*
*
NS
NS
C-48
-------
Table C-10 (continued)
Day
3
6
12
9
IS
Day
3
6
12
9
IS
Day
3
9
6
IS
12
Unit II Circulator (C12) - Organic h'eight
3 6 12 9
NS NS NS
NS NS
NS
--
Unit II Circulaf.or (Cl2) -Inorganic Keiqht
3 6 12 9
NS NS NS
NS NS
NS
--
Unit II Condenser (C12) - Total Weight
3 9 6 IS
-- * * *
NS NS
.'•- NS
--
15
*
*
NS
NS
15
A
*
NS
NS
12
*
NS
NS
NS
C-49
-------
Table C-10 (continued)
Unit II Discharge (C12) - Organic Weight
Day 3 6 9 12 1S
3 NS NS * *
6 -- NS NS *
9 -- NS *
12 -- NS
IS
Unit II Discharge (C12) - Inorganic Weight
Day 3 6 9 J2 15
3 . " NS NS * *
6 NS * *
9 -- * *
12 -- NS
IS
C-50
-------
APPENDIX D
ECONCMIC AND AVAILABILITY CONSIDERATIONS
OF BROMINE CHLORIDE
D-l
-------
ECONOMIC AND AVAILABILITY CONSIDERATIONS
OF BROMINE CHLORIDE
Cost comparisons of cooling water treatment with Cl, vs BrCl
are given below These estimates are based on biocide 6ost information
supplied by Dow Chemical (personal communication, Dr. Jack Mills) and Ethyl
Corporation (personal communication, Dr. A. H. Filbey) . Biocide costs were
based on a price of $0.22 per kg for chlorine and $0.55 per kg for BrCl
(costs of transportation and injection were assumed to be the same for both
biocides). In comparing the two biocides, it was assumed that effective
treatment resulted from a continuous chlorine or bromine chloride input of
2; rnP; • S °Sage °f 135° kg/day of each biocide Cthe amount required
ser^ow^ ;iC3/5tratl°?-o£ °'5.ppm * the coolinS streara) "d a 2onden-
ser flow of 31 m-Vsec, continuous injection of chlorine and bromine chloride
3$0/day- ** $75°/day' ^spectively. In other wordsTc^loro
of cooling water may be 2% times the cost of chloriAation.
ahlv ^ Pr^6 £°r broi?ine chloride, presently $0.55 per kg, would prob-
ably decline if mass production were initiated. Future pricing of this
product may follow cost trends of similar developmental product! as they
achieve adult status. Although the price of bromine chlSride is relatively
insensitive to fluctuations in the cost of energy*, future increases in
the cost of power may change this situation. increases in
Bromine chloride is made by mixing stoichiometric quantities of bro-
°ri
ni-ii i«-»*i-\ ° ~-~-i-»-"-i-w""-'-i -»•*- v(ucuii..i. 1.1.69 ux oro-
(Mills, 1975). The present U. S. bromine chloride produc-
stimated at 45 million kg per year. The capacity could
'^ •+' ----sed several fold within months, based on an estimate of the
capacity expandable within a year and/or adjustments in bromine end-use.
In_i97?' the total bromine production capacity in the United States
was over 225 million kg, divided among the five bromine producers: Dow,
Etnyl Corporation, Great Lakes, Michigan Chemical, and Arkansas Chemical
fcthyl Corporation, Great Lakes, and Dow control about 85% of the U. S. bro-
mine production capacity. With the 1976 increase in production, the total
U. S. capacity is estimated at about 250 million kg per year. If this pro-
duction were totally dedicated to bromine chloride, it would yield 360
million kg of bromine chloride.
The capacity for base bromine production could be easily and sub-
stantially increased by drilling additional brine wells and expanding sur-
Sf6 * SltieS'., WeU caPacity P^sently increases by 10% per year. The
present known underground bromine brine reserves in Arkansas and Michigan
will afford at least a 100-year bromine supply at present consumption levels.
* The energy cost of BrCl and C12 production is approximately 1 to 2 kwh
per pound; that of 03 is 10 to 12 kwh per pound.
D-2
-------
Additionally, there are large seawater reserves. Much of the present bro-
mine production is committed to various end-uses, including brominated or-
ganic and inorganic products. About 50-551 of the bromine produced is used
to manufacture ethvlene dibromide, a lead scavenger for gasoline. This
market is declining at about 101 per year because of the use of unleaded
gasoline in automobiles. Additional quantities of bromine thus will be
available in the future.
The present domestic consumption of chlorine for condenser cooling
water treatment is estimated at 27 million kg per year. This is about
0.5% of the domestic annual chlorine production (Chemical Marketing Reporter,
1973). If all power plants switched to BrCl, 27 million kg per year would be'
required for cooling water treatment.* The production of this amount of
BrCl would require 18 million kg of bromine, which is about 7% of the
present domestic production.
Assuming that BrCl effectiveness, as determined in the present study,
applies nationally.
REFERENCES
Chemical Marketing Reporter. 1973. Schnell Publishing Company, Inc. New
York, New York. May 1973.
D-3
-------
-------
APPENDIX E
THE SHIPPING, STORAGE,AND FEEDING OF BROMINE CHLORIDE
Contents
Shipping Bromine Chloride
Unloading and Storage
Bromine Chloride Feeding
Materials of Construction
Handling Precautions
E-l
-------
THE SHIPPING, STORAGE, AND FEEDING OF BROMINE CHLORIDE
(Prepared by Dr. Jack Mills, Dow Chemical, Midland, Mich.)
tprhnnf31711116 chioride shiPPing» storage, and feeding closely parallel chlorine
technology, with some important differences. For details concerning the shS-
SM srr i
e
'
S^
describe unloading procedures, materials of construction corrosivity,
analysis, environmental properties, and safe handling practices.
SHIPPING BROMINE CHLORIDE
Bromine chloride is classified by the Department of Transportation fDOTI
^Ann^051^ liqUld> Tt is avail*ble from Dow in tank cars, 'and S cVlinde
use- At the present
ures «i t v °£ bromine chloride ** bromine chloride
mixtures in steel tank trucks and tank cars similar to those used for chlorine:
• DOT Specification MC-331 tank motor vehicles having cargo
tanks of 225 psig service pressure and mimjnum wall thick-
ness of 0.625 inch.
• DOT Specification 105ASOOW tank cars or 106A500X tanks.
^A J?* I1CfT peimit reftricts the loading limit of tank cars to 110,000 pounds,
and their outage must be not less than 21. Smaller cylinders, -such as 150
pounds or less, da not require a DOT Special Permit but fall under the DOT
regulations covering corrosive liquids found in paragraphs 173-244 and 173-245
of the Code of Federal Regulations on Transportation.
+1, cAt-the Present time> bromine chloride shipments and use are regulated under
the Environmental Protection Agency Experimental Use Permit No. 464 -EUP-47, issued
July 9, 1976, under the provisions of the Federal Insecticide, Fungicide, and
Rodent ic ide Act.
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UNLOADING AND STORAGE
Chlorine unloading facilities, including unloading lines made of steel
can be used for bromine chloride. However, for longer service, it is re- '
commended that Kynar-lined steel pipe or its equivalent be used to transfer
liquid bromine chloride.
Bromine chloride should always be removed from a cylinder or tank car
as a liquid because the dissociation above the liquid produces a chlorine-
rich vapor. Therefore, cylinders loaded with BrCl contain dip tubes for
easy removal of the liquid under its own pressure. When liquid is withdrawn
by the prescribed method, its composition will remain substantially constant
throughout the removal process. On unloading bromine chloride from 3000-
pound cylinders or tank cars, special care must be taken to use the proper
(liquid) angle valve.
In some locations subject to low winter temperatures, the vapor pressure
in a tank car or cylinder may not be sufficient for unloading. The car or
cylinder may then be unloaded by padding - i.e., by the addition of completely
dry, oil-free, compressed air or nitrogen, similar to the procedure for chlorine
padding. However, because of its lower vapor pressure (30 psig) and higher
density (2.34 g/cc), BrCl may require padding more frequently than chlorine
normally does.
Tank cars loaded with bromine chloride are equipped with ball check valves.
If the valve is opened too rapidly, the ball check valve will close, and BrCl
will not flow. The liquid angle valve should never be used to regulate the
flow rate of BrCl. This valve must be kept completely open to allow the ex-
cess flow valve to close if the unloading line is broken.
The same instructions for storage of chlorine also apply to bromine
chloride storage. The corrosivity of BrCl to steel is sufficiently low
(0.93 mils/yr) to allow storage in steel-constructed cylinders and tank cars
for extended periods of time. However, it is recommended that BrCl not be
stored for more than 5 years in cylinders.
BROMINE CHLORIDE FEEDING
Bromine chloride can be utilized either in liquid or gaseous form.
Generally, it is withdrawn from containers as a liquid, piped to an evaporator,
changed to a gas, and fed through process equipment to the application point.
Capital Controls Company, Colmar, Pennsylvania, has developed a bromine
chloride vapor feed system which is a modification of their vacuum operated
gas chlorinator.
In contrast to chlorine feed systems, which require an evaporator only at
high feed rates, BrCl vapor feed systems always include an evaporator. The
evaporator may consist of a chamber immersed in a controlled, heated water bath,
which increases the temperature of the BrCl liquid, causing it to boil. Bromine
chloride liquid enters the chamber and maintains the required liquid level and
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pressure necessary to meet the vaporization rate for the gas demand The eas
released passes through the chamber and is super-heated as it leaves en route
to a vacuum regulator. The vacuum regulator, connected to a remote flow meter
reduces the pressure to a negative (vacuum) pressure. The metered gas is
directed to the ejector which creates the vacuum and mixes the gas with a
water system. The BrCl solution is piped from the ejector to the point of
is lost>the vaanm regulaSr
The BrCl feed system should be located in a room that is heated to 60° F
on and contains provisions for exhausting gas, should a leak develop.
> should not be routed through cool areas as this may cause
-eliquefaction in the process piping. If the application point is re-
mote from the equipment area, piping the BrCl solution to the required area
is recommended Before start-up, the BrCl feed system should be tested for"
leaks, using the prescribed method suggested by the equipment manufacturer.
The estimated cost of the BrCl feed system is comparable to that of a
tSir^iK A*°l™e fystem "hich includes the cost of a chlorine evaporator;
there will be additional cost depending on the choice of materials of construc-
u?n' • j C°ft .. the 400° pound P61" fey development system for feeding bromine
chloride at the Morgantown station was approximately $9500. Capital Controls
Company should be consulted for additional information concerning future pricing
of various size feeder systems for bromine chloride. p^-uig
MATERIALS OF CONSTRUCTION
Piping should be of schedule 80 seamless black iron or carbon steel.
Cast iron piping, fittings or equipment should never be used for BrCl service
since the possibility of failure is greater with such materials, and the con-
sequences of failure are likely to be serious. When bending of carbon steel
piping is necessary, it is best bent hot and stress relieved to prevent it
trom becoming hard and brittle and to reduce the likelihood of failure in
service.
Pipeline joints should preferably be flanged or welded. If threaded
joints are necessary, extreme care must be taken to obtain clean, sharp pipe
threads to ensure pressure-tight joints. Following the pipe-thread cutting
operation, the pipe should be reamed and wiped with a solvent-soaked rag to
remove cuttings and cutting oil. Solvents such as trichloroethylene or per-
cnloroetnylene are suitable for this purpose. Alcohols or hydrocarbons should
never be used. A small amount of a linseed oil and white lead paste is re-
commended as a pipe dope.
Piping should be well supported, protected against extremes in temperature,
and adequately sloped to allow drainage. Long liquid BrCl lines are not re-
commended, but, if used, they should be provided with shut-off valves at each
end. A properly designed expansion chamber, with a volume equivalent to 20%
of the volume of the pipe section, should be installed between the shut-off
valves at the highest point. Its purpose is to absorb increases in the volume
of BrCl caused by increases in temperature, and thus prevent hydrostatic rupture
of a full line. The Dow Chemical Company may be consulted on installation.
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Acceptable fittings include schedule 80 forged-steel welding tees and ells
cast steel 300-pound flanged ells and tees with ASA-faced and-drilled small
tongue-and-groove facings, and forged-steel, 2,000-pound screw-end elbows and tees.
Asbestos, impregnated with Teflon polytetrafluoroethylene, and graphite-
lubricated asbestos are common packing materials.
Gaskets should be of 31 antimony lead or of bonded asbestos fiber as per
Military Specification MIL-A-17472 (Navy) or equivalent. For pipe smaller than
2 inches, I/16-inch thick gaskets should be used; for pipe 2 inches or larger
gaskets should be 1/8 inch thick. Rubber gaskets are attacked by liquid BrCl'
and should never be employed.
Pressure gauges should be designed for BrCl service and be either the
diaphragm-protected type or the forged-steel, welded bourdon tube type.
Suitable diaphragms may be of Monel, silver, or tantalum. A pressure range
of not less than 0-250 psig is desirable. Gauge glasses are a potential
source of danger and are not recommended on BrCl equipment.
Special care should be taken in avoiding plastic materials which may be
attacked by liquid BrCl or its concentrated vapors. Polyvinyl chloride and
ABS plastic, which are common to chlorine feeding systems, should be avoided.
Plastic pipes made of PVC can be used to carry a water stream containing bromine
chloride from the point of injection. Kynar, Teflon, Viton, and other equivalent
highly resistant plastics are recommended as replacements for rubber, PVC, or ABS
plastics.
HANDLING PRECAUTIONS
Bromine chloride is a heavy, highly corrosive, fuming liquid with a sharp,
harsh, penetrating odor. Chemically, it is a very active oxidizing agent, both
as a liquid and a vapor. Liquid BrCl rapidly attacks the skin and other tissues,
producing irritation and burns which heal very slowly; even comparatively low con-
centrations of vapor are highly irritating and painful to the respiratory tract.
The warning properties of BrCl are such that a person will avoid gross over-
exposure if he is capable of getting to fresh air. However, repeated day-long
exposures to low levels may be injurious.
For emergencies, the preferred protection consists of self-contained breathing
apparatus; a rubber, neoprene, or suitable plastic slicker suit; neoprene rubber
gloves; rubber boots or high rubber shoes; and chemical worker's goggles. Full-
face plastic shields with forehead protection should be worn in addition to chemical
worker's goggles when complete face protection is desirable.
In case of gross vapor contact, immediately remove the victim to fresh air,
keep him warm and quiet, and call a physician immediately. If the person shows
signs of lung irritation, coughing, or respiratory embarrassment, 100% oxygen
should be administered by properly trained personnel.
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K t, ^* of ,?antfct W1*h ll?uld bromine chloride, the affected area should
be flooded immediately with copious quantities of water from a safety shower or
other source of flowing water, and medical help summoned. All contaminated
clothing, including shoes, should be removed as quickly as possiScwSS the
lif mf1S If1^ ?? SJ°Wer* Washillg should be Continued foH? leasHs minutes
and, if medical help has not arrived by then, continued for another 15 -minute
period. Contaminated clothing should be washed before reuse
If eye contact is made, the affected eye should be immediately irrigated
E^^VT1- Jtl6S -f rUnning Water' Eye fountains are preferable for
^g "J K' bf ' lf ?nVS not availaMe, a bubbler drinking fountain or a hose
with a liberal gentle flow may be utilized. The eyelids should be held LarT
during irrigation to ensure contact of water with all accessible tissues of the
eyes and the lids. Eyes should be washed continuously for at lean 15 mimrtes
and medical attention obtained immediately. minutes
In the event that a- BrCl leak is detected, it should be immediately located
and stopped. Even small leaks can create a safety hazSd Sd^Se slrioul
corrosion to equipment in the area. Ammonia should be used to detect leaks.
i« *o!5? 5°^°^ de5ontaminairts should be kept immediately at hand where BrCl
is handled (water-safety showers and eye-wash fountains should be provided for
Uzerfma^' ** 6yeS' ^ WeU ^ a h°Se £°r rinSing ""* "^^
• Anhydrous Ammonia - Cylinders of anhydrous ammonia should be
available for decontamination of atmosphere containing BrCl fumes.
• Lime Slurry or Dry Soda Ash - A slurry of hydrated lime or dry
soda ash may be applied to liquid BrCl spills to neutralize them.
• Potassium Carbonate or Sodium Carbonate Solution - These solutions
are prepared by dissolving five pounds of the carbonate in 10 quarts
of water. They are best for neutralizing halogen spills because
their heats of solution and reaction are lower than those of lime
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APPENDIX F
SITE AND PLANT CHARACTERISTICS OF THE MORGANTOWN
STEAM ELECTRIC STATION
Contents
Location and River Characteristics Near the Site
Cooling Water Flow
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SITE AND PLANT CHARACTERISTICS OF THE MORGANTOWN
STEAM ELECTRIC STATION
LOCATION AND RIVER CHARACTERISTICS NEAR THE SITE
PEPCO's Morgantown Steam Electric Station (SES) is located on the
25
Average water depth is about 7 m (23 ft) .
surface layers, and upstream at depth The
ranges typically between 140 to 1400 m3/sec (5000 to SOOOOrfsT
10 and 20
COOLING WATER FLOW
A once- through cooling system is employed at the plant to reject
6 hfat °t the twin 570-MWe generating onits. Separate condlnser
anrLeaCh mi?- J1? «»dcnser discharge from both condensers Inters
S5 J fCha5f canal'whlch ^turns the thermally elevated cooling water
ake g & momentum Jet located 0.5 km (0.3 mi) upstream of the
intake
t;tT,,,.1^CoolTing wa?er is drawn from the river through a deep-water intake
structure Lower layer withdrawal is accomplished by a combination of a
curtain wall reaching 10 m (33 ft) below the mean low water level and an
intake channel dredged to 15.2 m (50 ft), extending from the river channel
to the curtain wall. The intake channel is 520 m (1700 ft) long and 106 m
(350 ft) wide.
™-i temPer^ture a114 salinity vary continuously through the annual
cycle, the vertical density structure of the river water determines the
degree of selectivity in deep-water withdrawal. As long as salinity
differences of at least 0.1 ppt exist vertically, the curtain wall is
effective in drawing water from layers 10 m (33 ft) below the surface.
1his situation prevails during most of the year. Because there are longitu-
dinal temperature and salinity gradients in the river that vary tidally? the
depth of flow separation near the curtain wall may also change with a tidal
period.
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The cooling water,drawn in underneath the curtain wall at average
velocities of 0.09 to 0.15 m/sec (0-3 to 0.5 fps), is mixed rapidly in an
intake embayment (25000 m3) before entering the intake ports located behind
the bar racks and traveling screens. The pumphouse, which is the site
of chlorine injection into the cooling stream, is also located behind the bar
racks and vertical traveling screens. There are two sets of three pumps,
one set per generating unit. The maximum condenser flow per generating unit
is 31 m3/sec; the cooling water transit time (intake to outfall) is 65 min.
At full plant load, the heat absorbed by the cooling water amounts to
1.6 x IQll BTU per day. During passage through the condenser system, an
abrupt rise in water temperature, about 6 to 7° C, occurs.
Temperature decay through the discharge canal is slow, amounting to less
than 10% of the rise across the condensers. The phytoplankton, zooplankton,
fish eggs and larvae, and other small organisms present in the cooling water
will experience "a thermal dose of about 400 C degree-min for a 65-min tran-
sit time and an average temperature rise of 6°C.
In addition to thermal stresses, biota entrained in the cooling water
may be affected by mechanical stresses caused by abrasion, velocity shear,
and rapid pressure changes, estimated at 1.3 atmospheres. Although the
effects of mechanical stresses have not been quantitatively determined,
they should be considered in evaluating biocide and thermal stresses.
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/« TECHNICAL REPORT DATA
(Flease read Inunctions on the reverse before completing)
EPA-600/7-77-053
3. RECIPIENTS ACCESSION-NO.
4. T.TLE AND susT.TLE BRQMINE CHLORIDE--AN ALTERNA-
TIVE TO CHLORINE FOR FOULING CONTROL IN
CONDENSER COOLING SYSTEMS
5. REPORT DATE
May 1977
6. PERFORMING ORGANIZATION CODE
AUTHOR^) Leonard H. Bongers, Thomas P. O'Conner,
and Dennis T. Burton
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Martin Marietta Corporation
Environmental Technology Center
1450 South Rolling Road
Baltimore, Maryland 21227
10. PROGRAM ELEMENT NO.
EHE624
11. CONTRACT/GRANT NO.
68-02-2153
12. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Industrial Environmental Research Laboratory
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
Final: 5/76-1/77
4. SPONSORING AGENCY CODE
EPA/600/13
this report *Fred Roberts (EPA'
''A8STRACT The report gives results of a comparison of bromine chloride and chlorine
for fouling control in condenser cooling systems, by evaluating their decay rate in
estuarine cooling water and their fouling control effectiveness. The program was
conducted at an 1100-MWe, fossil-fueled, two-unit generating facility using estuarine
water for once-through cooling. The halogens were applied continuously at doses of
0. 5 ppm or less. Fouling control was evaluated by observing the accumulation of
fouling on glass panels exposed to treated and untreated cooling water, and on conden-
ser performance data. Decay characteristics of the halogens were evaluated by
measuring residual oxidant concentrations using an amperometric back-titration
method sensitive to 5 ppb. Fouling control resulted from the presence of bromamines
expected from the rapid reaction of free hypobromous acid with the ambient levels of
ammonia present. Dosing requirements depended primarily on cooling water temper-
ature. Using BrCl decay and fouling response to treatment data, a control model was
formulated which predicted minimum BrCl dose necessary to attain adequate fouling
control. BrCl was found to be effective when dosed continuously at 0. 5 ppm and less.
Oxidant residuals resulting from BrCl treatment were found to dissipate more rapidly
in the estuarine water than did the chlorine-induced oxidants.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIEHS/OPEN ENDED TERMS
c. COSATI Field/Group
Pollution
Cooling Systems
Condensers (Liquefiers)
Fouling Prevention
Bromine Halides
Pollution Control
Stationary Sources
Bromine Chloride
13 B
ISA
07A
13H
07B
3. DISTRIBUTION STATEMEN1
Unlimited
19. SECURITY CLASS (ThisReport)
Unclassified
21. NO. OF PAGES
171
20. SECURITY CLASS (Thispage)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
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