EPA-600/4-77-038
May 1977
600477038 fY]'
Environmental Monitoring Series
STUDY OF m
DETERMINE CHEMICA
EMAND
Environm
port Laboratory
nd Development
election Agency
I, Ohio 45288
-I
-------
RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination ol traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the ECOLOGICAL RESEARCH series. This series
describes research on the effects of pollution on humans, plant and animal spe-
cies, and materials. Problems are assessed for their long- and short-term influ-
ences. Investigations include formation, transport, and pathway studies to deter-
mine the fate of pollutants and their effects. This work provides the technical basis
for setting standards to minimize undesirable changes in living organisms in the
aquatic, terrestrial, and atmospheric environments.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
-------
EPA-600/4-77-038
May 1977
A STUDY OF NEW CATALYTIC AGENTS TO DETERMINE
CHEMICAL OXYGEN DEMAND
by
Ray F. Wilson
Texas,Southern University
Houston, Texas 77004
Grant No. R803779-01
Project Officer
Morris E. Gales, Jr.
Environmental Monitoring and Support Laboratory
Cincinnati, Ohio 45268
ENVIRONMENTAL MONITORING AND SUPPORT LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
-------
DISCLAIMER
This report has been reviewed by the Environmental Monitoring and
Support Laboratory, U.S. Environmental Protection Agency, and approved
for publication. Approval does not signify that the contents neces-
sairly reflect the views and policies of the U.S. Environmental Protection
Agency, nor does mention of trade names or commercial products constitute
endorsement or recommendation for use.
ii
-------
FOREWORD
Environmental measurements are required to determine the quality of
ambient waters and the character of waste effluents. The Environmental
Monitoring and Support Laboratory-Cincinnati conducts research to:
o Develop and evaluate techniques to measure the presence and
concentration of physical, chemical, and radiological pollutants
in water, wastewater, bottom sediments, and solid waste.
o Investigate methods for the concentration, recovery, and inden-
tification of viruses, bacteria, and other microbiological orga-
nisms in water. Conduct studies to determine the responses of
aquatic organisms to water quality.
o Conduct an Agency-wide quality assurance program to assure
standardization and quality control of systems for monitoring
water and wastewater.
There is an ever-increasing interest in improving methods to analyze
water and waste samples, whether the resulting data are to be used for
research, surveillance, compliance monitoring, or enforcement purposes.
Accordingly, the Environmental Monitoring and Support Laboratory has an
on-going methods research effort in the development, evaluation, and
modification of standard procedures. This particular report pertains to
procedural modification for chemical oxygen demand measurement. The
method has potential routine application for the analysis of chemical
oxygen demand in surface waters and domestic and industrial wastes.
Dwight G. Ballinger
Director
Environmental Monitoring and Support Laboratory
iii
-------
ABSTRACT
Of the several methods proposed for chemical oxygen demand (COD)
determinations, the dichromate reflux method has generally been adopted
as the standard procedure using silver sulfate as the catalyst. Inasmuch
as silver sulfate is extremely expensive, the purpose of this study was
to ascertain which of the nontoxic elements, iron, copper, zinc, aluminum,
etc. could be employed for a substitute catalyst for silver sulfate in
the procedure. The results obtained in this study show that among the
catalysts investigated, silver sulfate is generally the best for carrying
out COD determinations. However, substantially the same results could be
obtained from samples in the high-level range of approximately 500 milli-
grams by using a reduced amount of silver sulfate in combination with
magnesium sulfate.
A procedure is described for determining the COD values of solutions
having sample concentrations in the range 5 to 50 milligrams. The method
is a modification of the standard Moore procedure, in that a combination
of silver sulfate, aluminum sulfate, and magnesium sulfate is used to
replace the silver sulfate catalyst. This revised procedure is generally
comparable in completeness of oxidation and is less expensive than the
Moore procedure. Data are reported for pure synthetic organic samples
and for certain bayou samples.
This report was submitted in fulfillment of Grant No. R803779-01 by
Texas Southern University under the sponsorship of the U.S. Environmental
Protection Agency. This report covers the period July 20, 1975, to
December 20, 1977, and work was completed as of March 1, 1977.
iv
-------
CONTENTS
Foreword ............................... ill
Abstract ............................... iv
Acknowledgment ............................
1. Introduction ........................ 1
2. Conclusions ......................... 2
3. Recommendations ....................... 3
4. Experimental Procedures ................... 4
5. Results and Discussion ................... 7
References .............................. 11
Appendices
1. Effect of Silver Sulfate Using Moore Method for Deter-
mining Oxygen Consumed .................... 12
2. Effect of Different Volumes of Sulfuric Acid on COD Values
Using 15 ml of Silver Sulfate Catalyst ............ 13
3. Effect of Different Substitute Catalysts for Silver Sulfate
for Determining Oxygen Consumed ............... 14
4. Effect of Different Combination Catalysts for Determining
Oxygen Consumed ....................... 16
5. Effect of Time of Heat on COD Values of Acetic Acid Using
the Revised Moore Method .................. 18
6. Comparison of Certain COD Values Using Revised Method
Friedrich's Condenser Vs. Dry-Ice Condenser ......... 19
7. Carbon Content of Stock Sample Solutions Using Total Carbon
Analyzer ........................... 20
8. Statistical Analysis for Acetic Acid Using 15 ml Ag SO +
Igr MgS04 .......................... 21
9. Effect of Silver Sulfate Using Moore Method for Determining
Oxygen Consumed ....................... 22
-------
10. Effect of Different Catalysts on COD Values for Different
Organic Compound 23
11. Effect of Combinations Catalysts on COD Values for
Different Organic Compounds 24
12. Effect of Silver Sulfate on COD Values in the Presence
of Aluminum and Magnesium Sulfates 26
13. The Effect of Different Catalyst or Catalyst Combi-.
nations on COD for Acetic Acid 27
14. Standard Method Vs. Revised Method Using Houston Area
Water Samples 28
vi
-------
ACKNOWLEDGMENTS
The author wishes to extend sincere thanks to the personnel of the
Environmental Monitoring and Support Laboratory, especially Mr. Morris E.
Gales, Jr., for their invaluable assistance to the project. Also acknowl-
edged is the assistance of George Witt, Hessamodin Ebrahimzodeh,
Abdolkarim Ghafouripour, Mohammad Khorassani, Sharhrokh Shirazi, and
Patricia A. Smith for their help.
vii
-------
-------
SECTION I
INTRODUCTION
Previously several methods have been proposed for determination of
chemical oxygen demand (COD) values in certain waters and wastes. The
dichromate reflux method (1) using silver sulfate as a catalyst is gen-
erally accepted as the standard procedure (2) for COD determinations.
This method suffers from the fact that the availability of silver sulfate
is low and the cost of this catalyst is extremely high, presently approxi-
mately $400 per pound. In addition to the dichromate procedure, several
other less well accepted methods have been proposed, e.g., the iodic method
of Dzyadzio (3), later modified by Johnson, Halvorson, and Tsuchiya (4),
the permanganate method (5), the perchloratoceric acid procedure (6), and
the elimination of chloride interference in the dichromate reflux COD test
by Dobbs (7) and Williams and Baumann (8) by the addition of mercuric sul-
fate to form unionized mercuric chloride.
In attempting to control-our environment, we frequently need to know
the amount and extent of oxidation of organic matter in our water and waste
systems. Thus, there is a need for an economical, sensitive, and rapid de-
termination of oxygen required to oxidize the organic matter in waste sam-
ples. The low availability and high cost of silver sulfate catalyst employed
in the standard COD procedure give rise to a need for finding a low-cost
substitute catalyst. This study was undertaken, first, to ascertain which
of the nontoxic elements (iron, nickel, copper, zinc, aluminum, etc.), may
be used for a substitute or partial substitute catalyst for silver sulfate
in the standard COD procedure and secondly, to evaluate the best replacement
catalytic agent for COD determination, standardize the procedure, and test
its validity.
This project was divided into two phases. Phase (I) was concerned
with high level COD determinations and involved: (a) an evaluation of the
effect of sulfuric acid on the completeness of oxidation, (b) effect of
different proposed substitute catalysts, (c) effect of different combi-
nation catalysts, (d) effect of time of heating, and (e) a comparison of
COD values using the Friedrich's condenser versus a dry ice condenser.
In Phase (II), low level COD studies in the concentration range 5 to 50
milligrams per sample were carried out involving considerations similar
to those for high level COD determinations.
-------
SECTION II
CONCLUSIONS
This work has demonstrated
1. that among the catalysts studied, silver sulfate is generally
the best catalyst for carry out COD determinations.
2. that in the high-level, revised COD procedure substantially
the same COD values could be obtained using 15 ml of silver
sulfate solution in combination with 1 magnesium sulfate in-
stead of the 70 ml of silver sulfate solution required in the
standard COD procedure.
3. that in the low-level, proposed procedure comparable results
could be obtained by using 20 ml of sulver sulfate solution
in combination with 1 g aluminum sulfate and 1 g magnesium
sulfate instead of the 70 ml of silver sulfate solution re-
quired in the standard procedure.
4. that the data obtained using the standard method vs. the re-
vised method for measuring COD values of real water samples
showed that the revised method is comparable to the standard
method.
Preliminary work indicated that the COD values for certain extremely
volatile organic compounds could be materially increased by using a dry
ice condenser filled with crushed ice instead of a Friedrich's condenser.
These studies suggest that further studies using a dry ice or modified
dry ice condenser are desirable.
-------
SECTION III
RECOMMENDATIONS
1. In this study the Friedrich's reflux condenser was generally
employed; however, a limited number of determinations were
carried out using a dry ice condenser. The COD values for
certain volatile compounds was substantially higher when a
dry ice condenser filled with crushed ice was used. Thus
more studies should be carried out using a dry ice condenser.
2. Further studies should be carried out using a dry ice con-
denser filled with different freezing point mixtures.
3. It is recommended that further studies be carried out on
the variables such as time of heating and temperature of re-
fluxing medium using a dry ice or modified dry ice condenser.
4. It is recommended that the silver sulfate-magnesium sulfate-
aluminum sulfate catalyst replace the silver sulfate catalyst
in the Standard Chemical Oxygen Demand Method.
-------
SECTION IV
EXPERIMENTAL PROCEDURES
APPARATUS
Each reflux apparatus used consisted of a pyrex 500 ml round bottom
or Erlenmeyer flask fitted with a 24/40 taper-joint neck connected with a
Friedrich's reflux condenser or a dry ice condenser, in designated cases,
in which crushed ice was used. Standard hot plates were employed to heat
the reflux solutions. All samples, unless otherwise indicated, were run
in triplicate, simultaneously with a blank containing 50 ml of deionized
water.
A total organic carbon analyzer, model DC-50, obtained from the
Dohrmann Division, Division of Envirotech Corporation, Mountain View,
California, was used to verify the carbon content in the COD samples used
in this study. This instrument was standardized before each series of
determinations against reagent grade potassium hydrogen phthalate dis-
solved in deionized water.
REAGENTS AND SOLUTIONS
All solutions were prepared from reagent grade chemicals. For high-
level range COD determinations (approximate range of 500 mg of sample
per liter), standard potassium dichromate, 0.250 N, was prepared by
dissolving 12.2588 g of dried K Cr 0 in a 1 liter flask and diluting the
solution to volume. Sulfuric acid containing 23.5 g of silver sulfate per
9 Ib bottle was employed after allowing two days for complete dissolution.
Phenanthroline ferrous sulfate (ferrion) indicator solution was prepared by
dissolving 98 g of 1-10 (ortho) phenanthroline monohydrate and 0.70 g of
FeSO,.7H90. Standard ferrous ammonium sulfate, approximately 0.250 N was
prepared by dissolving 98 g of Fe(NH,)~(SO ) 6H.O in deionized water, then
adding 20 ml of concentrated sulfuric acid, cooling, and diluting the
solution to a volume of 1 1. The standard ferrous ammonium sulfate was
standardized daily as its concentration decreases on standing.
Standard reagents solutions for low level COD determinations were
prepared as described above for the high level procedure, except the
solutions were made one-tenth the concentrations used in the high-level
procedure. For bayou samples which contained chlorides, mercuric sulfate
was added to the digestion flask to complex the chlorides, thus eliminating
the chloride interference, except for samples which contained a very high
chloride and required a chloride correction (2).
-------
CALCULATIONS
1. Theoretical COD: A typical theoretically calculated COD, Mg/1,
for acetic acid is presented using the following balanced equation
HC2H302 + 202 2C02 + 2H20
The theoretical COD in this case for a 500 mg sample of acetic dcid
is:
COD, mg/1 = 500 mg °f HC2H3°2 X 64 mg o£ °2/2 mmoles = 533 mg °f °2
60 mg of HC-H 0 mmoles 1
2. Experimental COD value: The experimental COD values reported in
this study are expressed in mg/1 using the following equation.
mg/1 COD = (A - B)C x 8,000
ml sample
where: COD. = Chemical Oxygen Demand, mg/1 of sample
A = ml of ferrous ammonium sulfate used for blank
B = ml of ferrous ammonium sulfate used for sample
C = the normality of ferrous ammonium sulfate.
RECOMMENDED REVISED MOORE HIGH LEVEL COD PROCEDURE
Several boiling stones are placed in a reflux flask which has been
placed in an ice bath. To this flask is added 25 ml of potassium dichro-
mate solution, 15 ml of silver sulfate solution (23.5 g of silver sulfate
per 9-16 bottle of cone, sulfuric acid) plus one gram magnesium sulfate.
While swirling the resultiing solution, 55 ml of concentrated sulfuric acid
and 50 ml of a test COD sample which contained an accurately known amount of
compound ranging from approximately 250 to 500 mg of sample per liter are
added to the mixture in the reflux flask. After this solution is refluxed
for two hours, the flask is allowed to cool, and the inside of the condenser
is washed with 25 ml of deionized water. Ten drops of ferrion indicator are
added to the solution at room temperature and the excess potassium dichro-
mate is titrated with 0.25 N ferrous ammonium sulfate to the ferrion end
point, where the solution changes from blue green to reddish brown. The
COD values of the aromatic hydrocarbons are increased markedly by sub-
stituting a dry ice cooled condenser, filled with crushed ice (frozen
water), in place of a Friedrich's condenser.
-------
RECOMMENDED REVISED MOORE LOW LEVEL COD PROCEDURE
Several boiling stones are placed in a reflux flask which has been
placed in an ice bath. To this flask is added 25 ml of potassium dichro-
mate, 20 ml of silver sulfate solution (23.5 g of silver sulfate per 9-lb
bottle of cone, sulfuric acid) plus one gram magnesium sulfate and one gram
aluminum sulfate. While swirling the resulting solution, 50 ml of concen-
trated sulfuric acid and 50 ml of a test COD sample which contained an
accurately known amount of compound ranging from approximately 5 to 50 mg
of sample per liter are added to the mixture in the reflux flask. After
this solution is refluxed for two hours, the flask is allowed to cool, and
the inside of the condenser is washed with 25 ml of deionized water. Ten
drops of ferrion indicator are added to the solution at room temperature
and the excess potassium dichromate is titrated with 0.025 N ferrous ammo-
mium sulfate the ferrion end point.
-------
SECTION V
RESULTS AND DISCUSSION
PHASE I
The first part of this study consisted of evaluating the COD values
of ten selected organic compounds by using various amounts of silver sulfate
solution (23.5 g Ag^SO, per 9 ob bottle) as a catalyst. The concentration
effect of silver sulfate as a catalyst was ascertained by determining the
COD values for each of ten selected compounds in the presence of 5, 10, 15,
20, 35, 50, 70 ml of the silver sulfate solution. The organic compounds
selected represent different classes of organic substances that may be
found in wastewater. A solution of each of the ten organic compounds
was prepared by dissolving approximately 500 mg of each in 100 ml of de-
ionized water and diluting to 1000 ml. The results of the oxidation of
these compounds are shown in Table 1. According to these tabular data
acetic acid and ethyl alcohol gave essentially the same results in the
presence of 15 ml of silver sulfate solution as the 70 ml recommended in
the standard procedure. These results suggest that using 15 ml of silver
sulfate solution gives substantially the same catalytic effect as 70 ml.
Such reduction in the required amount of silver sulfate catalyst gives
rise to approximately a 4-fold reduction in the cost of running a COD
determination because of the materially high cost of sulver sulfate.
The effect of sulfuric acid concentration on typical COD values
obtained using the standard Moore COD procedure is shown in Table 2.
These results show that high-percentage results are generally obtained
with high sulfuric acid concentrations. For the compounds studied, that
are almost completely oxidized by 15 ml of silver sulfate solution plus
55 ml of sulfuric acid, significantly lower COD values were obtained at
very low sulfuric concentrations.
In the third part of this study 16 suggested substitute catalysts
were employed to obtain chemical oxygen demand values for the same organic
compounds which were used in the first step. It should be emphasized that,
although used for this study, none of these individual catalysts could be
used as a replacement for silver sulfate giving the same completeness of
oxidation of the compounds studied as are shown in Table 3. These data,
however, do indicate that several of the catalysts do give high COD values
for certain of the high molecular weight organic compounds.
The various combination of different catalysts such as
-------
1" 1 g Fe2(S04)3 + 1 g A12(S04)3
2" 1 g A12(S04)3 + 1 g MgS04
3" 1 g Fe2(S04)3 + 1 g MgS04
4" 1 g MgSO. + 15 ml Ag0SO. solution
004 °2 4
5" 1 g A12(S04)3 + 15 ml Ag2S04 solution
6" 1 g Fe2(S04)3 + 15 ml Ag2S04 solution
7" 1 g MgS04 + 1 g A12(S04)3 + 15 ml Ag2S04 solution
8" 1 g MgS04 + 1 g Fe2(S04)3 + 15 ml Ag2S04 solution
9" 1 g Fe2(S04)3 + 1 g A12(S04)3 + ml AgS04 solution
were used in the last step. The evaluation of the above catalysts with the
ten different organic compounds showed that 15 ml of silver sulfate solution
in combination with MgS04> Al (S04> , or Je (SO.) gave reasonable higher
COD values as compared to the first three combination catalysts as shown
in Table 4. The data in Table 4 indicate that comparable COD values are
obtained for most of the above ten compounds when 15 ml of silver sulfate
solution plus one gram of MgS04 are used to replace the 70 ml of silver
sulfate solution required as the catalyst in the standard COD procedure.
The magnesium sulfate-silver sulfate suggested replacement catalyst combina-
tion for silver sulfate does not substantially oxidize pyridine or aromatic
hydrocarbons. These results are similar to one obtained using 70 ml of
silver sulfate solution in the standard procedure. However, preliminary
studies, Table 6, indicated that the COD values for aromatic hydrocarbons
are materially increased by substituting a dry ice cooled condenser filled
with crushed ice in place of a Friedrich's condenser. The selection of
the best possible cooling mixture for a dry ice condenser in COD deter-
minations should justify further study.
The results of the oxidation of these compounds showed that formal-
dehyde is oxidized by 74% when 70 ml of silver sulfate solution is used
and 69% when 15 ml of silver sulfate solution is used in the standard
procedure, acetic acid is 99% oxidized and 92% oxidized when 15 ml of
silver sulfate solution is used as a catalyst (see in Table 1).
For high molecular weight organic compounds, viz., toluene, oleic
acid, benzene, certain of the new catalysts gave higher oxidation values
than 70 ml of silver sulfate solution. For example, toluene is oxidized
by ferric oxide (70.5%), and benzene is oxidized by aluminum sulfate (38.7%),
whereas silver sulfate gave respective oxidation values of 38.1%, 32.2%,
37.6% for toluene, oleic acid, and benzene (see Table 3).
Tabular data for effect of time of heating on COD values of acetic
acid are shown in Table 5. Typical data were obtained for other compounds
that are readily oxidized in boiling dichromate sulfuric acid solution,
which indicate that such compounds are generally and substantially oxidized
within the recommended 2-hour digestion period.
-------
Typical data of the carbon content of stock sample solutions using
the total carbon analyzer described above under Apparatus are reported in
Table 7. These measurements were carried out to verify and test the com-
parative accuracy of the revised procedure.
Statistical treatment of certain data obtained in this study was carried
out as described by Laitinen and Harris (9). Eleven replicate measurements
of COD values for acetic acid, reported in Table 8 using the revised method
proposed in this study gave a mean of 489 with a standard deviation of two
COD units. The 95% confidence interval of the mean and the standard de-
viation are 489 + and 1 to 8, respectively.
The data obtained in this phase of the study show that among the
catalysts studied, silver sulfate is generally the best catalyst for carry-
ing out COD determinations. However, substantially the same results could
be obtained using 15 ml of silver sulfate solution in combination with 1 g
magnesium sulfate. Thus, based on the data obtained in this study, the
already described procedure is proposed for carrying out chemical oxygen
demand determinations in the high level concentration range, thereby ob-
taining essentially the same COD values as those of the standard Moore
method at less expense.
PHASE II
Inasmuch as the Moore method using silver sulfate as a catalyst has
generally been accepted as a standard method for carrying out COD deter-
minations, this procedure was selected for the studies reported herein.
The primary emphasis in this study was to find a recommended replacement
catalyst in the low level COD range of 5 to 50 mg of sample, for silver
sulfate because of the extremely high cost of this catalyst.
The concentration effect of silver sulfate catalyst using the standard
Moore method on eleven different organic compounds that might be found in
certain wastes are shown in Table 9. These tabular data indicate that
20 ml of silver sulfate solution gives COD values fairly close to the ones
obtained for 70 ml of silver sulfate solution for most of the compounds
Based upon exploratory tests, the 5 catalysts (MgSO,, Al (SO ) , Fe (SO,),
CaSO, and ZrOSO,) were selected for detail study using eleven organic sub-
stances. These studies were carried out by placing accurately weighed
samples of approximately 50 mg of each organic compound in separate 1 liter
volumetric flasks and diluting the volume with deionized water. The data
for these studies are shown in Table 10. Among the catalysts employed,
MgSO, and A1.(SO,), generally gave fairly high COD value; however, none of
the 5 catalysts were effective in oxidizing acetic acid.
In an attempt to ascertain the additive catalytic effect of the afore-
mentioned 5 selected catalysts, these catalysts were grouped in pairs
giving rise to ten possible combinations. The pair combination catalytic
effect of these catalysts are shown in Table 2 . The MgSO, and Al-tSO )
generally gave the highest COD value.
-------
The effect of silver sulfate concentration on COD values in the
presence of ong gram each of aluminum sulfate and magnesium sulfate are
reported in Table 12. Correlation of these tabular data with the ones re-
ported in Table 9, with the exception of acetic acid, show that 20 ml of
silver sulfate solution in combination with aluminum sulfate and magnesium
sulfate generally gave COD values fairly comparable to the ones obtained
using 70 ml of silver sulfate solution.
Tabular data reported in Table 13 for true samples taken from selective
sites locations in the Houston Ship Channel and adjoining wastewaters show
that the COD values obtained using the revised procedure proposed in this
study are comparable to the one determined using the standard procedure.
10
-------
REFERENCES
1. Moore, W. Allan, F. L. Ludzack, C. C. Ruchhoft. Determination of
Oxygen Consumed Values of Organic Wastes. Analytical Chemistry, 23,
p 1297, 1951.
2. Methods for Chemical Analysis of Water and Wastes, EPA-625/6-74-003,
Method Development and Quality Assurance Research Laboratory, National
Environmental Research Center, U.S. Environmental Protection Agency,
Office of Technology Transfer, Washington, D. C. 20460, 1974.
3. Dzyadzio, A. M., Vodosnabzhenie i sanit. Tekh., No. 8-9, pp 117-25,
1938.
4. Johnson, P. W., H. 0. Halvorson, and H. M. Tsuchiya. Abstracts of
109th meeting, American Chemical Society, Atlantic City, p 25, 1946.
5. Standard Methods for the Examination of Water and Sewage, 9th edition.
American Public Health Association, New York, 1946.
6. Pitt, W. W., S. Katz, and L. H. Thacker. A Rapid Senstive Method for
the Determination of COD in Polluted Waters. Water Alche Series,
pp 1-5, 1972.
7. Dobbs, R. A., and R. T. Williams. Elimination of Chloride Interferences
in the Chemical Oxygen Demand Test. Analytical Chemistry, 35, p 1064,
1963.
8. Bauman, F. J. Dichromate Reflux Chemical Oxygen Demand. A Proposed
Method for Chloride Correction in Highly Saline Wastes. Analytical
Chemistry 4£, p 1336, 1974.
9. Laitinen, H. A., and W. E. Harris Chemical Analysis, 2nd Edition,
McGraw-Hill Book Company, New York, pp 540-541, 1960.
11
-------
TABLE 1. EFFECT OF SILVER SULFATE USING MOORE METHOD FOR
DETERMINING OXYGEN CONSUMED
Volume of Silver Sulfate Solution
COD Values, mg/1 (% of Recovery)
Compounds
Acetic
acid
Benzene
Tert-Butyl
alcohol
Ethyl
alcohol
Formalde-
hyde
3-Hydroxy-
pyridine
Oleic acid
Pyridine
Sucrose
Toluene
0
36.0(6.8)
37.8(2.5)
223(34.4)
346(33.2)
308(57.8)
844(37.1)
141(19.5)
-
-
427(27.3)
5
364(68.3)
98.0(6.4)
467(72.0)
650(62.3)
331(62.1)
966(42.5)
174(24.1)
10.0(0.7)
559(99.6)
244(15.6)
10
436(81.8)
208(13.5)
542(83.6)
759(72.7)
347(65.1)
838(36.9)
214(29.6)
10.0(0.7)
526(93.8)
262(16.7)
15
490(91.9)
304(19.8)
571(88.0)
824(79.0)
370(69.4)
834(36.7)
289(40.0)
18.0(1.2)
526(93.8)
306(19.6)
20
528(99.0)
185(12.0)
584(90.0)
887(85.0)
312(58.5)
954(42.0)
362(50.0)
15.0(1.0)
559(99.6)
246(15.7)
35
530(99.4)
83.3(5.3)
607(93.6)
942(90.3)
293(55.0)
954(42.0)
407(56.3)
27.7(1.9)
556(99.1)
211(13.5)
50
532(99.8)
81.5(5.3)
616(95.0)
950(91.0)
300(56.3)
952(41.9)
403(55.7)
-
554(98.8)
185(11.8)
70
530(99.4)
578(37.6)
646(99.6)
946(90.7)
396(74.3)
846(37.2)
407(56.3)
-
553(98.6)
594(38.0)
-------
u>
TABLE 2. EFFECT OF DIFFERENT VOLUMES OF SULFURIC ACID ON COD* VALUES
USING 15 ml OF SILVER SULFATE CATALYST
Volume of l^SO^,
COD Values, mg/1 (% of
Compounds
Acetic acid
Benzene
Tert-Butyl alcohol
Ethyl alcohol
Formaldehyde
3-Hydroxypyridine
Lactic acid
Oleic acid
Sucrose
Toluene
10
304(57.0)
92( 6.0)
224(34.5)
356(34.1)
368(69.0)
784(34.5)
220(41.3)
28( 3.9)
504(89.8)
60( 3.8)
20
324(60.8)
148( 9.6)
388(59.8)
352(33.7)
380(71.3)
788(34.7)
208(39.0)
36( 5.0)
516(92.0)
153( 9.8)
ml
Recovery)
30
352(66.0)
360(23.4)
396(61.1)
352(33.7)
372(69.8)
808(35.5)
236(44.3)
180(24.9)
524(93.4)
380(24.3)
40
364(68.3)
450(29.2)
468(72.2)
360(34.5)
376(70.5)
844(37.1)
256(48.0)
215(29.7)
528(94.1)
470(30.0)
55
490(91.9)
304(19.8)
571(88.0)
824(79.0)
370(69.4)
834(36.7)
480(90.0)
289(40.0)
526(93.8)
306(19.6)
i
*Each COD value was calculated from triplicate determinations
-------
TABLE 3. EFFECT OF DIFFERENT SUBSTITUTE CATALYSTS FOR SILVER
SULFATE FOR DETERMINING OXYGEN CONSUMED
COD Values, mg/1 (% of Recovery)
Catalysts*
Compounds
Acetic acid
Benzene
Tert-Butyl alcohol
Ethyl alcohol
Formaldehyde
3-Hydroxypyridine
Oleic acid
Pyridine
Sucrose
Toluene
NONE
36.0(6.8)
37.7(2.5)
446(68.8)
346(33.2)
308(57.8)
842(86.9)
143(19.8)
-
522(98.0)
492(31.4)
Ag2S°4
520(97.5)
578(37.6)
646(99.6)
936(89.7)
396(74.3)
847(87.5)
233(32.2)
-
532(95.0)
596(38.1)
MgS04
27.9(5.2)
74.8(4.9)
472(72.8)
560(53.7)
381(71.5)
846(87.4)
246(34.0)
-
540(96.0)
772(49.3)
MgO
27.9(5.2)
257(16.7)
444(68.5)
571(54.7)
381(71.5)
852(88.0)
210(29.0)
-
508(101)
756(48.3)
Mg(N03)2
35.9(6.7)
121(7.9)
464(71.5)
556(53.3)
388(72.8)
848(87.0)
536(74.1)
-
-
294(18.8)
Fe2(S04)3
69.7(13.1)
154(10.0)
496(76.5)
560(53.7)
369(69.2)
988( 102)
468(64.7)
-
572(102)
282(18.0)
-------
TABLE 3 (continued)
COD Values, mg/1 (%
Catalysts
Compounds
Acetic acid
Benzene
Tert-Butyl alcohol
Ethyl alcohol
Formaldehyde
3-Hydroxypyridine
Oleic acid
Pyridine
Sucrose
Toluene
F62
43.8(8.
416(27.
512(78.
567(54.
360(67.
843(87.
575(79.
-
556(99.
183(11.
2)
0)
9)
3)
7)
1)
5)
0)
7)
Mn02
35.9(6
304(19
409(63
450(43
376(70
797(82
274(37
-
368(66
-
.7)
.8)
.2)
.7)
.5)
.3)
.9)
-
.4)
-
A12(SO
39.8(7
596(38
627(96
600(57
361(67
840(86
421(58
-
4>3
.5)
.7)
• 7)
.5)
.7)
.7)
.1)
-
of Recovery)
CuO
49.8(9
79.4(5
419(64
564(54
380(71
.3)
.2)
.6)
.0)
• 3)
988( 102)
189(26
-
.1)
-
568( 101)
132 ( 8
.4)
460(29
.4)
ZnSO
8.0(1
28.0(1
409(63
400(38
374(70
826(85
392(41
-
560(99
79.0(5
4
-5)
.8)
.0)
.3)
.2)
.3)
.7)
-
.8)
.0)
CdSO.
4
43.5(8.2)
404(26.3)
544(83.9)
364(34.9)
386(72.4)
957(98.8)
333(46.0)
-
548(97.7)
88.9(5.7)
*In Tables Ilia, Illb and IIIc, seventy milliliters of Ag2S04 solution or in the other cases
1 gram of the specified catalyst was used, except that only 0.1 gram of any platinum element com-
pound was employed.
-------
TABLE 4. EFFECT OF DIFFERENT COMBINATION CATALYSTS
FOR DETERMINING OXYGEN CONSUMED
Compounds
Acetic acid
Benzene
Tert-Butyl alcohol
Ethyl alcohol
Formaldehyde
3-Hydroxypyridine
Oleic acid
Pyridine
Sucrose
Fe (SO )
M2(S(y3
23.8(4.5)
317(20.6)
395(60.9)
325(31.1)
323(60.6)
819(84.6)
631(87.2
6.0(0.5)
516(92.0)
COD Values,
+ MgSO +
59.5(11.2)
460(29.9)
532(82.0)
331(31.7)
532(99.8)
835(89.3)
675(93.3)
29.8(2.4)
552(98.4)
mg/1 (% of Recovery)
MgSO +
Fe^(SO, )
i 2 43
71.4(13.4)
339(22.0)
442(68.1)
363(34.8)
385(72.2)
887(91.6)
417(57.6)
37.7(3.0)
561 ( 100)
MgSO +
15 ml. Ag2S04
514(96.4)
603(39.2)
608(93.7)
1,017(97.5)
405(76.0)
857(88.5)
-
43.6(3.4)
181(11.6)
-------
TABLE 4 (continued)
COD Values*, mg/1 (Z of Recovery)
Compounds
Acetic acid
Benzene
Tert-Butyl
Alcohol
Ethyl
Alcohol
Formaldehyde
3-Hydroxy-
pyridine
Oleic acid
Pyridine
Sucrose
Toluene
15 ml. Ag2S04
444(83.3)
577(37.5)
573(88.3)
923(88.4)
373(70.0)
752(77.7)
-
19.8(1.4)
-
143( 9.1)
15 ml. Ag2S04
440(82.6)
567(36.9)
546(84.1)
859(82.3)
371(69.6)
954(98.5)
-
15.9(1.1)
556(95.0)
105( 6.7)
MgSO + Fe2(S04).
15 ml. Ag2S04
474(88.9)
672(43.7)
593(91.4)
913(87.5)
383(86.5)
838(86.5)
466(64.4)
37.7(2.6)
552(98.4)
162(10.4)
, Fe.(SO ), +
f £• J
15 ml. Ag2S04
476(89.3)
469(30.5)
558(86.0)
722(69.2)
344(64.5)
836(86.3)
539(74.5)
38.7(2.7)
515(91.8)
156(10.0)
MgS04 + A12(S04)3
+ 15 ml. Ag2S04
520(97.5)
612(40.0)
624(96.2)
871(83.5)
371(69.6)
834(86.1)
352(48.7)
19.8(1.4)
555(98.9)
120( 7.7)
*In each case one gram of each catalyst plus 15 ml of
solution was used.
-------
TABLE 5. EFFECT OF TIME OF HEAT ON COD VALUES OF ACETIC ACID
USING THE REVISED MOORE METHOD
Time, Minutes
1) After 30 Minute Shaking
2) Before Boiling Point
3) 5 Minute After Boiling
4) 10 "
5) 15 "
6) 20 "
7) 25 " " "
8) 30 " "
9) 35 "
10) 40 "
11) 60 "
12) 80 "
13) 100 "
14) 140 "
15) 180 "
16) 220 "
17) 340 "
Mean COD* Value, mg/1
20.0
68.0
236
244
300
316
328
340
412
448
460
476
496
504
504
508
508
% of Recovery
3.8
12.8
44.3
45.8
56.3
59.3
61.5
63.8
77.3
84.0
86.3
89.3
93.0
94.5
94.5
95.3
95.3
*Mean COD values were determined from triplicate determinations using the
recommended revised Moore procedure.
18
-------
TABLE 6. COMPARISON OF CERTAIN COD VALUES USING REVISED METHOD
FRIEDRICH'S CONDENSER VS. DRY-ICE CONDENSER
Compound
1) Sodium Stearate***
2) Glutamic Acid
3) Isobutyric Acid
4) Acetic Acid
5) Toluene
6) Benzene
Mean COD,** mg/1
604(44.9)
448(78.4)
592(65.1)
490(91.9)
306(19.6)
304(19.8)
Mean COD* Value. mg/l(%)
792(58.8)
460(80.5)
888(97.7)
500(93.8)
748(47.8)
792(51.5)
**COD values determined using a Friedrich's condenser
*COD values determined using a dry ice condenser filled with crushed ice-
water mixture
***Sodium stearate's low value appears to result partially from incomplete
oxidation
19
-------
TABLE 7. CARBON CONTENT OF STOCK SAMPLE SOLUTIONS USING
TOTAL CARBON ANALYZER
Organic Compound
Formaldehyde
Benzene
Toluene
Acetic Acid
Sucrose
Ethyl Alcohol
Oleic Acid
T-butyl Alcohol
3-Hydroxypyridine
Lactic Acid
Pyridine
Carbon Taken, mg/1
200.0
461.0
456.0
200.0
210.5
260.8
382.9
324
316
200
380
Carbon Found, mg/1
193.9
451.4
448.1
192.1
205.7
268.5
390.6
317.8
308.4
207.0
385.2
% Error
3.1
2.1
1.7
4.0
2.3
3.0
2.0
2.0
2.3
4.0
1.5
20
-------
TABLE 8. STATISTICAL ANALYSIS FOR ACETIC ACID
USING 15 ml AgS0 + Igr MgS(>
Mean COD Value, Mg/1 (% of Recovery)
488(91.5)
492(92.3)
492(92.3)
488(91.5)
488(91.5)
488(91.5)
488(91.5)
488(91.5)
488(91.5)
492(92.3)
488(91.5)
Mean 489
Sd. dev. +1.87
Coeff. of
Var. .4%
Theoretial
Value 533
% Recovery 91.7
-------
TABLE 9. EFFECT OF SILVER SULFATE USING MOORE METHOD FOR
DETERMINING OXYGEN CONSUMED
Volume of Sliver Sulfate Solution
COD Values, mg/1 _(% of Recovery)
Compounds
0
10
15
20
35
50
70
to
to
Acetic
acid
Benzene
Tert-Butyl
alcohol
Ethyl
alcohol
Formalde
hyde
3-Hydroxy-
pyridine
Lactic acid
Oleic acid
Pyridine
Sucrose
Toluene
28.3(53.1) 31.5(59.1) 33.0(62.0) 35.5(66.6) 37.7(70.7) 45.6(85.5) 51.8(97.1) 52.2(98.0)
19.4(12.6) 13.7( 8.9) 12.8( 8.3) 6.2( 4.0) 14.0( 9.1) 10.0( 6.5) 75.5(49.1) 66.5(43.2)
53.1(41.0) 60.5(46.6) 65.6(50.6) 68.3(52.7) 71.9(55.4) 74.9(57.7) 76.7(59.1) 77.4(57.7)
36.8(35.3) 80.8(77.4) 87.8(84.1) 98.8(88.0) 93.4(89.5) 95.8(91.8) 98.2(94.1) 98.5(94.4)
34.8(65.3) 37.0(69.4) 36.4(69.3) 31.5(59.1) 37.7(70.7) 33.0(61.9) 51.8(97.2) 47.2(88.6)
83.2(85.9) 86.6(39.1) 84.4(37.1) 90.9(93.9) 91.2(94.2) 93.3(96.3) 94.0(97.1) 89.0(91.1)
44.0(82.5) 45.6(85.5) 47.6(89.3) 48.4(90.7) 49.0(92.0) 51.6(96.8) 51.8(97.1) 51.9(97.3)
30.1(20.9) 13.3( 9.2) 11.2( 7.7) 29.2(20.2) 19.8(13.7) 46.8(32.4) 26.9(18.6) 33.9(23.4)
0.8( 0.6) 0.8( 0.6) 0.9( 0.7) 1.2( 0.9) 3.5( 2.8) 9.2( 7.2) 13.9(11.0) 14.3(11.3)
49.1(87.5) 53.2(94.9) 52.4(93.4) 50.1(89.3) 50.4(89.9) 50.7(90.4) 52.2(93.0) 53.6(95.5)
53.5(34.2) 42.3(27.0) 24.0(15.3) 10.9( 7.0) 12.4( 7.9) 7.3( 4.7) 20.8(13.3) 14.5( 9.3)
-------
TABLE 10. EFFECT OF DIFFERENT CATALYSTS ON COD VALUES
FOR DIFFERENT ORGANIC COMPOUND
COD Values, mg/1 (% of Recovery)
Compounds
Acetic acid
Benzene
Tert-Butyl alcohol
Ethyl alcohol
Formaldehyde
3 -Hy dr oxypy r id ine
Lactic acid
Oleic acid
Pyridine
Sucrose
Toluene
A12(S04)3
10.0(18.8)
20.2(13.1)
60.6(46.7)
51.5(49.4)
36.0(67.4)
74.3(76.7)
41.6(78.0)
25.5(17.6)
0.8( 0.6)
51.7(92.2)
44.4(28.4)
CaSO.
4
6.3( 11.8)
11. 0( 7.2)
61. 0( 47.0)
20. 5( 19.6)
41. 0( 76.9)
97.0(100.2)
43. 0( 80.6)
28.0(19.4)
0
-
33.0(21.0)
MgS04
8.0(15.0)
25.5(16.6)
59.0(45.5)
52.3(50.1)
35.5(65.9)
76.4(78.9)
41.6(78.0)
10. 1( 7.0)
2.0( 1.6)
52.5(93.6)
19.8(12.7)
Fe2(S04)3
2.0( 3.8)
27.9(18.1)
48.1(37.1)
48.3(46.0)
35.2(65.9)
76.0(78.5)
25.5(47.8)
39.6(27.4)
.40(3.2)
51.7(92.2)
25.1(16.0)
ZrOSO.
4
5.2( 9.8)
12. 0( 7.8)
54. 0( 41.6)
30. 0( 28.8)
48. 0( 90.0)
-
51. 5( 96.6)
32. 8( 22.7)
5.2( 4.1)
66.0(101.5)
56. 0( 35.8)
-------
TABLE 11. EFFECT OF COMBINATIONS CATALYSTS ON COD VALUES
FOR DIFFERENT ORGANIC COMPOUNDS
COD Values, mg/1 (%
Compounds
Acetic acid
Benzene
Tert-Butyl alcohol
Ethyl alcohol
Formaldehyde
3-Hydroxypyridine
Lactic acid
Oleic acid
Pyridine
Sucrose
Toluene
Al (SO ) +
figsoj
29.6(55.5)
46.8(30.4)
79.2(61.0)
55.6(53.3)
42.0(78.8)
77.2(79.7)
45.6(85.5)
31.2(21.6)
6.8( 5.40)
51.2(91.3)
50.4(32.2)
Al (SO ) +
CaSO, J
4
8.5( 15.9)
6.4( 4.2)
29. 0( 22.3)
31. 0( 29.7)
42. 0( 78.8)
107 (110.5)
31. 0( 58.1)
46. 0( 31.8)
3.1( 2:4)
61.0(108.6)
3.7( 2.4)
of Recovery)
Al (SO ) t
Fi2(S&4?3
8.4(15.8)
17.4(11.3)
49.6(38.2)
51.5(49.4)
38.8(72.8)
78.0(80.5)
36.4(68.3)
24.8(17.2)
5.6( 4.4)
56. 1( 100)
16.4(10.5)
Al (SO ) +
ZrOSO?
4
7.0(13.1)
5.5( 3.6)
34.1(26.3)
40.5(38.8)
37.3(70.0)
-
45.0(84.4)
28.2(19.5)
1.4( 1.1)
54.3(96.7
7.8( 5.0)
Fe (SO ) +
ZrOSO^ *
9.2( 17.3)
12. 0( 7.8)
74. 8 (57.?)
76. 0( 72.0)
55.0(103.3)
-
55.6(104.2)
54. 2( 37.5)
4.8( 3.8)
-
38. 0( 24.3)
-------
TABLE 11 (continued)
ro
in
COD Values, mg/1 (% of Recovery)
Compounds
Acetic acid
Benzene
Tert-Butyl alcohol
Ethyl alcohol
Formaldehyde
3-Hydroxypyridine
Lactic acid
Oleic acid
Pyridine
Sucrose
Toluene
Fe (SO ) +
HgSOj ^
7.0(13.1)
10. 5( 6.8)
49.3(38.0)
52.7(50.5)
33.8(63.4)
71.8(74.1)
32.2(60.4)
32.6(22.5)
5.1(4.00)
14.4(25.7)
12. 4( 7.9)
Fe (SO ) +
CaSO,
4
8.7( 16.3)
4.1( 2.7)
37. 5( 29.0)
36. 0( 34.5)
45. 0( 84.4)
-
53. 0( 99.4)
47. 0( 38.9)
3.0( 2.4)
60.5(107.8)
10. 0( 6.4)
MgSO +
CaSO,
4
7.5( 14.0)
5.0( 3.2)
31. 3( 24.1)
33. 0( 31.6)
46. 0( 86.3)
96. 0( 99.1)
37. 0( 69.4)
27. 0( 18.7)
2.0( 1.6)
63.0(112.2)
8.5( 5.4)
MgSO +
ZrOSO.
4
6.0( 11.3)
6.0( 4.0)
39. 6( 30.5)
38. 0( 36.4)
42. 8( 80.3)
-
40. 0( 75.0)
23. 6( 16.3)
0
59.2(105.5)
5.6( 3.6)
CaSO, +
ZrOSO.
4
12. 4( 23.3)
4.3( 2.8)
31. 0( 24.0)
37. 0( 35.5)
33. 0( 62.0)
102.0(105.3)
36. 0( 67.5)
42. 0( 29.0)
2.4( 2.0)
58.0(103.3)
5.1( 3.2)
-------
TABLE 12. EFFECT OF SILVER SULFATE ON COD VALUES IN THE
PRESENCE OF ALUMINUM AND MAGNESIUM SULFATES
Volume of Silver Sulfate Solution
COD Values, mg/1 (% of Recovery)
Compounds 0 5 10 15 20 35 50 70
Acetic
acid 29.6(55.5) 35.6(66.8) 39.9(74.9) 44.0(82.6) 46.0(86.3) 50.1(93.9) 50.8(95.3) 51.5(96.6)
Benzene 46.8(30.4) 41.5(27.0) 50.1(32.6) 50.4(32.8) 54.6(35.5) 66.1(43.6) 71.2(46.3) 69.9(45.4)
Tert-Butyl
alcohol 79.2(61.0) 85.0(65.5) 88.4(68.2) 91.9(71.0) 98.5(73.99) 100.1(77.2) 107.9(83.2) 109.3(84.3)
Ethyl
alcohol 55.6(53.3) 84.4(81.0) 87.1(83.5) 95.0(91.0) 94.1(90.2) 98.4(94.3) 98.4(94.3) 95.6(91.6)
Formalde-
hyde 42.0(78.8) 43.1(80.9) 41.5(77.9) 41.9(98.6) 48.3(90.6) 51.7(97.0) 51.7(97.0) 52.8(99.1)
3-Hydroxy-
pyri-
dine 77.2(79.7) 79.1(81.7) 80.3(82.9) 86.4(89.2) 86.9(89.7) 90.1(93.1) 95.0(98.1) 91.5(94.5)
Lactic
acid 45.6(85.5) 47.2(88.5) 47.0(88.1) 48.2(90.4) 49.9(93.6) 51.1(95.9) 52.5(98.4) 52.9(99.2)
Oleic
acid 31.2(21.6) 18.9(13.1) 17.4(12.0) 31.5(21.8) 27.5(19.0) 51.3(35.5) 43.1(29.8) 50.2(34.7)
Pyridine 6.8( 5.4) 7.0( 5.5) 7.2( 5.7) 7.5( 5.9) 7.9( 6.2) 8.7( 7.0) 9.5( 7.5) 10.7( 9.5)
Sucrose 51.2(91.3) 51.7(92.2) 52.4(93.4) 53.3(95.0) 53.8(95.4) 53.5)95.4) 54.0(96.3) 54.6(97.3)
Toluene 50.4(32.2) 51.5(32.9) 52.8(33.7) 54.5(34.8) 58.4(37.3) 69.2(44.2) 76.7(49.0) 77.9(49.8)
-------
TABLE 13. THE EFFECT OF DIFFERENT CATALYST OR CATALYST
COMBINATIONS ON COD FOR ACETIC ACID
Catalyst
Ig A12(S04)3
Ig MgS04
Ig MGS04 + Ig A12(S04)3
Ig MgS04 + Ig A12(S04)3 + 5 ml
Ig MgS04 + Ig A12(S04)3 + 10 ml
Ig MgS04 -f Ig A12(S04>3 + 15 ffll
Ig MgS04 + Ig A12(S04)3 + 20 ml
Ig MgS04 + Ig A12(S04)3 + 50 ml
Ig MgS04 + Ig A12(S04)3 + 70 ml
COD, mg/1 (% of Recovery)
10.0(18.8)
8.0(15.0)
29.6(55.5)
Solution 35.6(66.8)
" 39.9(74.9)
„ 44.0(82.6)
" 46.0(86.3)
" 50.8(95.3)
" 51.5(96.6)
27
-------
TABLE 14. STANDARD METHOD VS. REVISED METHOD USING
HOUSTON AREA WATER SAMPLES
Mean COD, mg/1
Sample Site Location Standard Method
1
2
3
4
5
6
7
8
9
10
11
12
- Buffalo Bayou-Franklin
at U.S. Post Office
- Allen's Landing at Main
- First Southwest Downfall
- Buffalo Bayou at Eastex
Freeway
- Brown & Root
- Buffalo Bayou at Lockwood
- Northside Sewage Treatment
Plant
- Ship Channel Turning Basin
- 610 Bridge
- Sims Bayou at Ship Channel
- Olins Downfall #1 on Ship
Channel
- Bouy #139 in Ship Channel
34.0
26.8
20.4
30.8
32.0
40.8
89.6
95.6
116.4
99.6
135.2
152.4
Revised Method
Standard Method
Revised Method X100
45.6
28.4
58.0
49.5
34.6
50.6
69.6
105.5
144.8
120.4
155.6
164.45
134
106
284
161
108
124
78
110
124
121
115
108
Av. 131
28
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/4-77-038
2.
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
A STUDY OF NEW CATALYTIC AGENTS TO DETERMINE CHEMICAL
OXYGEN DEMAND
6. REPORT DATE
May 1977 (Issuing Date)
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Ray F. Wilson
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Department of Chemistry
Texas Southern University
Houston, Texas 77004
10. PROGRAM ELEMENT NO.
1BA027 1HA323
11. CONTRACT/GRANT NO.
R803779-01
12. SPONSORING AGENCY NAME AND ADDRESS
Environmental Monitoring & Support Lab.
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, OH 45268
- Gin., OH
13. TYPE OF REPORT AND PERIOD COVERED
7/20/76 - 12/20/77
14. SPONSORING AGENCY CODE
EPA/600/06
15. SUPPLEMENTARY NOTES
16. ABSTRACT
This study was made to find a catalyst to replace silver sulfate in the COD
method in order to reduce the cost of the determination. The results show that
comparable results to the standard method for concentration of 50-500 mg/1 could be
obtained using a reduced amount of silver sulfate in combination with magnesium
sulfate. Another procedure is described for determining COD in the range of
5-50 mg/1 using a combination of silver sulfate, aluminum sulfate and magnesium
sulfate to replace silver sulfate.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Magnesium sulfates
Water analysis
Catalytic
Chemical oxygen demand
(COD)
Silver Sulfate
07B
18. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY CLASS (ThisReport/
UNCLASSIFIED
21. NO. OF PAGES
37
20. SECURITY CLASS (Thispage)
UNCLASSIFIED
22. PRICE
EPA Form 2220-1 (9-73)
29
U. S. GOVERNMENT PRINTING OFFICE: 1977-757-056M37 Region No. 5-11
-------
-------
-------
-------
-------
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Technical Information Staff
Cincinnati, Ohio 45268
OFFICIAL BUSINESS
PENALTY FOR PRIVATE USE, S3OO
AN EQUAL OPPORTUNITY EMPLOYER
POSTAGE AND FEES PAID
US. ENVIRONMENTAL PROTECTION AGENCY
EPA-335
Special Fourth-C lass Rate
Book
I
5
o
V
%
\
UJ
If your address is incorrect, please change on the above label;
tear off; and return to the above address.
If you do not desire to continue receiving this technical report
series. CHECK HERE l~~|. tear off label, and return it to the
above address.
------- |