&EPA
United States
Environmental Protection
Agency
Municipal Environmental Research EPA-600/2-78-115
Laboratory July 1978
Cincinnati OH 45268
Research and Development
Biodegradation
Studies of
Carboxymethyl
Tartronate
-------
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 of 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 ENVIRONMENTAL PROTECTION TECH-
NOLOGY series. This series describes research performed to develop and dem-
onstrate instrumentation, equipment, and methodology to repair or prevent en-
vironmental degradation from point and non-point sources of pollution. This work"
provides the new or improved technology required for the control and treatment
of pollution sources to meet environmental quality standards.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
-------
EPA-600/2-78-115
July 1978
BIODEGRADATION STUDIES
OF
CAKBOXYMETHYL TARTRONATE
by
E. F. Earth
H. H. Tabak
C. I. Mashni
Biological Treatment Section
Wastewater Research Division
Municipal Environmental Research Laboratory
Cincinnati, Ohio 45268
MUNICIPAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
-------
DISCLAIMER
This report has been reviewed by the Municipal Environmental Research
Laboratory, U.S. Environmental Protection Agency, and approved for publica-
tion. Mention of trade names or commercial products does not constitute
endorsement or recommendation for use.
11
-------
FOREWORD
The Environmental Protection Agency was created because of increasing
public and government concern about the dangers of pollution to the health
and welfare of the American people. The complexity of that environment and
the interplay between its components require a concentrated and integrated
attack on the problem.
Research and development is that necessary first step in problem solu-
tion and it involves defining the problem, measuring its impact, and
searching for solutions. The Municipal Environmental Research Laboratory
develops new and improved technology and systems for the prevention, treat-
ment, and management of wastewater and solid and hazardous waste pollutant
discharges from municipal and community sources, for the preservation and
treatment of public drinking water supplies, and to minimize the adverse
economic, social, health, and aesthetic effects of pollution. This publica-
tion is one of the products of that research; a most vital communications
link between the researcher and the user community.
This report describes biodegradation studies conducted on the chemical
carboxymethyl tartronate, which has been considered as a replacement for
phosphates in laundry detergents.
Francis T. Mayo
Director
Municipal Environmental Research
Laboratory
iii
-------
ABSTRACT
Carboxymethyl tartronate (CMT) was shown to be biodegradable in bench
scale activated sludge reactors.
After initial exposure to CMT in continuous flow systems an acclimation
period of 14 weeks was necessary before efficient degradation occurred.
Once acclimated to CMT the biomass could be starved in regard to this
substrate for at least 1.6 times the sludge age and still retain capacity
to degrade the material upon re-introduction.
Activated carbon was not found to be effective for CMT removal at a pH
value of 7.
iv
-------
CONTENTS
Foreword iii
Abstract iv
Figures vi
Tables vii
Acknowledgement viii
1. Introduction 1
2. Conclusions and Recommendations 3
3. Materials and Methods 4
Biodegradation apparatus 4
Municipal wastewater 8
Synthetic waste 8
Special inocula 9
General analytical methods 10
Analytical methods for CMT 10
4. Results
Continuous flow reactors 13
300 ml reactor studies 19
CMT starvation studies 19
Carbon adsorption studies 20
5. Discussion 22
References 23
Appendices 25
A. Analytical methods 26
B. Carbon adsorption 32
-------
FIGURES
Number
1 5.7 liter Suspended Growth Reactors 6
2 300 ml Suspended Growth Reactors
3 GMT and TOC of Reactor Effluents with Synthetic Feed 14
4 CMT and TOG of Reactor Effluents with Synthetic
Feed and External Inoculum 17
A-l Comparative Analytical Methods for CMT in Reactor Effluent ... 27
A-2 Resolution of CMT by Gas Chromatography 31
B-l Carbon Adsorption of CMT at Various pH Values 34
vi
-------
TABLES
Number Page
1 Composition of Builder M 5
2 Efficiency and Operational Data for Synthetic Feed
Reactors for a Period of 23 Weeks 15
3 Efficiency and Operational Data for Synthetic Feed
and External Inoculum Reactors for a Period of
18 Weeks 18
4 Degradation of CMT in Synthetic and Municipal
Wastewater Using 300 ml Reactors 20
5 Stability of Acclimated Biomass for Biodegradation
of CMT 21
B-l Carbon Adsorption of CMT 33
vii
-------
ACKNOWLEDGEMENTS
The cooperative help of the Monsanto Chemical Company, St. Louis,
Missouri was appreciated. Dr. William Gledhill and Mr. Paul MacDonald,
of Monsanto Chemical Company, visited the Laboratory and assisted in the
reported studies.
Mr. Timothy Miller, University of Cincinnati, aided in the project
during the summer of 1976.
Mr. Robert Bloomhuff, Municipal Environmental Research Laboratory,
provided analytical assistance.
Mrs. Rita Bender, Municipal Environmental Research Laboratory, prepared
the manuscript for final publication.
viii
-------
SECTION I
INTRODUCTION
In recent years, the national concern for protecting natural waters
from environmental pollution has been extended to the problem of accelerated
eutrophication due to man's activities. Although the basic understanding
of all causes of eutrophication is not fully agreed upon, it is certain
that compounds of nitrogen or phosphorus can contribute significantly to the
problem.
In the case of phosphorus compounds it is recognized that about half
the phosphorus content of municipal wastewater is derived from phosphate
containing detergents. Since municipal wastewaters are discharged as a
point source, control of effluent phosphorus compounds could be achieved by
banning phosphates in detergents, or by modified process control at the
wastewater facility. In view of the low residual phosphorus required for
eutrophication control it is likely both approaches will be implemented (1).
Phosphates in synthetic detergent formulations serve as water softeners,
therefore any material that would chelate calcium ions can be considered as
a replacement for phosphates. Various organic chelating agents have been
evaluated by Pollard (2)- Bunch and Ettinger (3) studied the biodegradation
of a series of organic chelating agents using the Bunch and Chambers test
procedure (4). For various reasons none of the compounds studied by these
investigators gained acceptance as a commercial replacement for phosphates
in the United States.
It may be reasonably assumed that current regulatory attitudes and past
experience by detergent manufacturers will dictate that neither toxic or
nondegradable materials will be introduced into a detergent product. Recent-
ly attention has been directed towards synthetic, nitrogen free, ether
polycarboxylates as phosphate replacements for use in areas where phosphates
have been restricted. A material of this type has been synthesized by
Lamberti (5). The material is trisodium carboxymethyl oxysuccinate (CMOS).
Biodegradation and other environmental tests are currently being conducted
by the manufacturer. Another compound of this class, trisodium carboxy-
methyl tartronate (CMT) has been investigated by Gledhill (6). Using
continuous and semi-continuous activated sludge processes he reported that
CMT was biodegradable after a suitable acclimation period for the micro-
organisms .
-------
Trade journals indicated that this latter compound would be vigorously
promoted and production could reach 70 million kilograms annually by the
year 1978 (6, 7).
It can be estimated that municipal wastewater would contain CMT at a
concentration of 20 mg/1 if this material replaced all the phosphate in
today's detergent formulations.
In anticipation of this product's wide scale distribution, it was deemed
important that the Municipal Environmental Research Laboratory confirm the
biodegradability of CMT.
-------
SECTION 2
CONCLUSIONS AND RECOMMENDATIONS
CONCLUSIONS
As a result of this research these conclusions have been reached:
1. Trisodium 20-oxa-l, 1, 3-propane tricarboxylate (carboxymethyl
tartronate or CMT) is biodegradable by activated sludge treatment.
2. An acclimation period of 14 weeks is required before the biomass
develops a population capable of efficient degradation.
3. External innoculum of soil and municipal wastewater microorganisms
into a synthetic medium did not reduce the acclimation period.
4. Once acclimated the biomass retained the capacity to degrade CMT for
at least 1.6 times the sludge age in the absence of the substrate.
5. Activated carbon was efficient in adsorption of CMT from distilled
water at pH 3. At pH values of 7 and 9 carbon adsorption was not effective.
6. The synthetic wastewater employed in these studies gave similar
results when compared with municipal wastewater.
RECOMMENDATION
In view of the above the following recommendation is made:
1. The degradation of CMT in anaerobic sludge digestion systems
should be investigated.
-------
SECTION 3
MATERIALS AND MEHODS
Chemistry and Characteristics of Carboxymethyl Tartronate (CMT)
CMT can be described as trisodium 2-oxa-l, 3-propane tricarboxylate in
the international nomenclature system. This chemical is the major ingredient
in a formulation named "Builder M" which is combined with synthetic surfac-
tants to produce a complete laundry product.
"Builder M" functions to sequester calcium and magnesium ions in
aqueous solution. It is a buffering agent, has deflocculating properties,
is compatible with other ingredients such as bleaches, and is stable in
neutral and basic solution over a wide range of temperature. The material
is not stable in strong acid solution.
Commercial lots of "Builder M" are expected to contain mixtures of
several polycarboxylates and other ingredients. A typical formulation would
have the composition shown on Table 1 (8) . For the work described in this
report Lot #237028 "Builder M" was used. It had a CMT content of 78 percent.
Throughout the report this material will be identified as CMT.
Biodegradation Apparatus
Bench-scale Bio-oxidation Units:
One portion of the biodegradation studies on CMT was conducted with
aerobic suspended growth reactors of 5.7JI capacity constructed as described
by Ludzack (9) . This continuous flow type unit is shown on Figure 1.
The feed solution for the reactors was placed in 20fc capacity poly-
ethylene containers and stored in a refrigerator maintained at 5°C to
retard microbial action. Mixing, to prevent settling of the feed solution,
was accomplished by low rate air addition through a coarse bubble sparger
located in the containers. Chemical metering diaphragm pumps transferred
the feed solution from refrigerated storage to the reactors maintained at
room temperature. Effluent from the reactors were collected in 201 capacity
glass bottles.
300 ml Bio-oxidation Units:
Continuous flow studies were also performed with 300 ml aerobic reactors
shown on Figure 2. Feed solution for these reactors was contained in 4SL
-------
glass bottles. Refrigeration was not provided. Mixing of the feed was
accomplished by magnetic stirrers. A Technicon Auto Analyzer manifold pump
was used to transfer the feed to the small reactors through the side inlet
to the aeration chamber. Reactor effluent was collected in 4& glass bottles.
These reactors were maintained at room temperature.
Biomass Development:
Initial studies on CMT degradation were conducted with the 5.7£ of
mixed licjuor from an activated sludge pilot plant treating municipal waste-
water were placed in the reactor. Synthetic wastewater, on a continuous
flow basis, was then started and the reactors were operated in this fashion
for one month before actual experimentation on CMT.
Throughout the entire study, sludge was wasted from the reactors to
maintain the biomass at a concentration of about 2,500 mg/1 on a volatile
solids basis.
Feed Solutions
At different times during the study the feed to the bio-oxidation
reactors was either municipal wastewater or a synthetic waste prepared from
laboratory reagents.
TABLE 1. COMPOSITION OF BUILDER M
Name of Ingredient Chemical Structure Percent of Total
Product
(Weight Basis)
Carboxymethyl Na°2? c°2Na 78
tartronate (CMT) H-
-------
FIGURE 1. 5.7 Liter Suspended Growth Reactors
-------
FIGURE 2. 300 ml Suspended Growth Reactors
-------
Municipal Wastewater:
When studying the biodegradation of CMT with municipal wastewater feed
the source of wastewater was the Wilmer Avenue interceptor sewage of the
City of Cincinnati. The collected raw wastewater was settled for 0.5 hr and
the supernatant filtered through a layer of glass wool before transfer to
the dosing container. Each second day the dosing containers were thoroughly
washed before being returned to service.
Synthetic Waste:
In order to eliminate the variable nature of municipal wastewater and
prevent possible introduction of toxic materials during the acclimation
period a synthetic waste was used in most of these studies. This feed
solution was formulated after a review of prior published formulations (10
through 23).
The final synthetic waste solution, prepared by diluting stock solutions
with distilled water had the following composition:
Constituent Concentration, mg/1
KH PO 8.5
22
Na HPO 33
NH4C1 2
MgSO 22
CaCl2 36
FeCl3
Urea
50
NaHCO 30°
Yeast Extract (Difco) 55
Baco Peptone (Difco) 50
Meat Extract (Difco) 50
Fish Meal Extract (Purina Trout Chow) 0.5 ml
-------
The fish meal extract was prepared by grinding lOg of Purina Trout
Chow with 200 ml of distrilled water in a high speed blender for 3 min. The
mixture was allowed to settle for 10 min and then 0.5 ml added to each liter
of synthetic waste. Experience has shown this additive helps control bulk-
ing of sludges produced from synthetic feeds.
The synthetic feed typically has the following characteristics:
Item Concentration, mg/1
Chemical oxygen demand 160
Total organic carbon 76
Suspended solids 2
Total Kjeldahl nitrogen 47
Ammonia nitrogen 2
Nitrite and nitrate nitrogen <0.1
Total phosphorus 13
Alkalinity, as calcium carbonate 215
pH 7.3 units
The nitrogen and phosphorus content is slightly higher than most
municipal wastewaters. However it was deemed necessary to have these
nutrients in excess to insure the waste was not growth limiting. The
suspended solids are low because the waste is composed of soluble materials
for ease of preparation of the feed from stock solutions.
Special Inocula
To insure that an acclimated biomass could be developed, on occasion a
soil extract or wastewater concentrate was added to the reactors to provide
a diversity of microorganisms.
Soil Extract:
To prepare a soil extract 50g of forest soil and 50g of garden soil;
both collected in Anderson Township, Ohio, were added to 1£ of distilled
water and blended at high speed for 1 min. The blend was transferred to
an Erlenmeyer fask and shaken on a rotary shaker for 15 min. The mixture
was then allowed to settle for 0.5 hr. The resulting supernatant was used
to inoculate the reactors to yield 2 percent by volume of the mixed liquor.
-------
Wastewater Concentrate:
Wastewater from the Wilmer Avenue interceptor sewer of the City of
Cincinnati was placed in a refrigerator and allowed to settle for six hours.
The supernatant was discarded and the settled solids were used to inoculate
the reactors to yield 2 percent by volume of the mixed liquor.
General Analytical Methods
Except as noted all methods were in accordance with the procedures
authorized in "Standard Methods for the Examination of Water and Wastewater,1
13th Edition (24) . The tabulation below lists the various tests and pro-
cedures used according to the cited pages of Standard Methods.
Test Procedure Page Number
pH Glass electrode 276-281
Temperature Mercury thermometer 348-349
Alkalinity Potentiometric 52-55
Suspended solids 224C 537-538
Total solids 224A 535
Volatile suspended 224D 538
solids
Volatile total solids 224B 536
Chemical oxygen demand Bichromate reflux 495-499
Kjeldahl nitrogen Digestion 469
*
Ammonia nitrogen Automated 616-620
*
Oxidized nitrogen Automated 620-624
*
Phosphorus, total Automated 624-628
* 14th Edition of Standard Methods
Analytical Methods for CMT
Two methods were used to determine CMT. A colorimetric method, which
is simple and fast but non-specific and therefore subject to interferences,
was employed for daily monitoring of CMT concentrations. A gas chromato-
graphic method which is specific but time consuming and cumbersome was used
periodically to check the colorimetric results.
All analytical results in this report are based on using Lot #237028 of
"Builder M" as 100 percent CMT content; since this* single lot was used
throughout the study for both reference and working samples.
10
-------
Colorimetric Method:
Except for minor modifications the colorimetric method is the same as
that reported by Viccaro and Ambye for the analysis of carboxymethyloxy-
succinate (25).
The method is based on the hydrolysis of CMT to glycolic acid, which
in turn yields formaldehyde in the presence of high concentrations of
sulfuric acid. 3-naphthol is added to condense with the formaldehyde to
form a highly colored diarylamine. The intensity of the color is propor-
tional to the concentration of CMT in the original sample. A detailed
description of the method is given in Appendix A, Part I.
A thorough shakedown of the method was made before the biodegradation
studies were initiated. Samples of distilled water, tap water, secondary
effluent and raw wastewater were dosed with quantities of CMT up to 20
mg/1. Linear and consistent responses were obtained on all samples except
CMT in distilled water. This unusual problem was circumvented by using tap
water for reference samples. The erratic results with distilled water are
probably due to the lack of ions to stabilize the colored end product of
the reaction. As with many colorimetric procedures occasional aberrant
results were experienced. Minor fluctuations of CMT content of duplicate
samples raised doubts about the reliability of the method. A thorough test
of the method was made in September 1976. A total of 34 samples of
standards and test samples were assayed independently by both MERL and
Monsanto Chemical Company personnel. The collective results agreed well
and indicated the procedure was suitable for daily monitoring.
Samples of raw wastewater and final effluents containing no added CMT
seldom exceeded 2 and 1 mg/1 respectively. This background level is
probably due to materials such as glycolic acid and acetaldehyde which can
be expected in low concentrations in wastewaters.
Gas Chromatographic Method:
The gas chromatographic method used in this study was developed by
C. B. Warren of Monsanto Chemical Company and has not been published. It
is based on esterification of CMT with n-propyl alcohol. A detailed
description is given in Appendix A, Part II.
Experiments with raw wastewater and secondary effluent dosed with CMT
at different concentrations produced linear response in peak height.
However plots of detector response versus CMT concentration shifted with
different samples, although no interferring substances were noted in any
wastewater or effluents. Also duplicate samples of a CMT standard solution
occasionally produced inconsistent results. These anomalies are suspected
to be due to incomplete esterification of CMT.
11
-------
Since both the colimetric and gas chromatographic procedures were
shown to have inherent limitations, the fate of CMT in these biodegradation
studies was not judged by any single analysis but rather by establishing a
pattern of results and comparison of the results obtained by each procedure.
12
-------
SECTION 4
RESULTS
5.7 Liter Continuous Flow Reactor Studies
The biodegradation of CMT at a concentration of 20 mg/1 in synthetic
feed was studied with and without inoculum of soil extract and wastewater
concentrate. In each case a control reactor, without CMT addition was
operated under similar conditions as the experimental reactors.
Synthetic Feed Only:
Table 2 gives the operational characteristics and efficiency for the
experimental and control reactors during this portion of the study, which
covered a period of 23 weeks. The values for CMT are not given because an
acclimation period for degradation was required and several spike doses were
added; therefore, average values would be meaningless. The data on Table 2
shows the reactors were operated under a control scheme that was favorable
to oxidation of COD, TOC and organic nitrogen. Almost all the oxidized
nitrogen was in the nitrate form.
Values for nitrite in the effluents never exceed 2 mg/1. The control
and CMT experimental reactor produced nearly identical quality effluent
indicating no adverse effect of the 20 mg/1 CMT dose on overall efficiency.
Figure 3 shows the CMT concentration of the effluent from each reactor
on a weekly average basis for the entire study period. Also shown is the
TOC concentration of the CMT reactor effluent. The control reactor's
effluent TOC values were slightly lower during the early portion of the
study and slightly higher during the later portion. As shown on Table 2
the average TOC values for both effluents, over the entire study, were
equivalent.
The figure shows that the control effluent gave small but measurable
amounts of CMT when using the colorimetric procedure due to the non-specific
nature of the assay. Starting at week #1 with the first introduction of the
20 mg/1 CMT feed the CMT concentration of the experimental reactor effluent
increased greatly. For a period of 12 weeks the CMT content of the effluent
was erratic. The CMT concentration did not approach the control values
until week #14 and then stabilized to near background levels for four weeks.
At that time the feed CMT concentration was increased to 50 mg/1 for a
period of two weeks. The reactor degraded the increased concentration of
CMT to background levels. The feed concentration was then increased to
100 mg/1 CMT for a period of two weeks. After an initial slight rise in
13
-------
O)
E
o
z
u
0 TOC, EXPERIMENTAL
REACTOR
CMT, EXPERIMENTAL
REACTOR (20 mg/l)
CMT, CONTROL
REACTOR
50 mg/l CMT
O
100 mg/l CMT
4 6 8 10 12 14 16 18 20 22 24
TIME, PROGRESSIVE WEEKS
FIGURE 3. CMT and TOC of Reactor Effluents
with Synthetic Feed
14
-------
TABLE 2. Efficiency and Operational Data for
Synthetic Feed Reactors for a Period
of 23 Weeks
Efficiency Items
COD, mg/1
TOC, mg/1
SS, mg/1
NH4-N
Oxidized-N, mg/1
TKN, mg/1
Total-P
Reactor
Average and
Control
Feed Effluent
161 20
148-175 11-32
79 9
70-88 3-16
2 3
1-11 1-8
3 1
1-4 0.1-9
0.1 33
0.1-0.4 14-51
41 2
34-48 0.2-10
13 13
11-15 9-24
Alkalinity, mg/1 as 180 56
CaC03 102-243 14-80
Range
CMT Experimental
Feed Effluent
159 22
151-175 12-29
79 10
69-89 2-17
2 3
1-8 1-10
2 1
1-3 0.1-9
0.3 33
0.1-1.8 24-53
41 2
35-48 0.2-10
13 13
11-15 8-23
186 53
144-245 13-86
Operational Items
pH , units
DO , mg/1
Temperature , C
MLSS, mg/1
MLVSS, mg/1
Volatile , Percent
Control Reactor
6.9-7.3
3.8
2.4-5.0
20.6
20.0-21.5
3,200
3,000-3,600
2,100
1,900-2,400
66
61-72
F/M, g COD/g MLVSS/d 0.29
0.20-0.36
SRT , days
17
15-18
Hydraulic detention time, hr 6
CMT Experimental Reactor
6.9-7.3
3.7
2.8-4.2
20.8
20.0-21.5
3,300
2,900-3,700
2,200
1,900-2,700
67
62-75
0.28
0.21-0.35
17
15-18
6
15
-------
effluent CMT the experimental reactor's effluent CMT concentration began to
decline toward background concentrations.
It was concluded that an activated sludge biomass developed with the
synthetic wastewater, without an external inoculum of microorganisms, could
acclimate to CMT and efficiently degrade the material. The on-set of
acclimation however did not occur until 12 to 13 weeks of continuous expo-
sure to CMT. Once acclimation occurred the biomass could efficiently
degrade increased concentrations of the material.
Synthetic Feed With Soil Extract and Wastewater Concentrate as
Inoculum:
To determine if the long acclimation period observed in the previous
continuous flow study could be shortened, by adding an external source of
microorganisms to enhance population diversity, an additional study was
performed.
Two reactors, one a control and the other receiving 20 mg/1 of CMT,
were operated in the same manner as the previous study. Each 48 hours the
continuous flow reactors were dosed with soil extract and wastewater con-
centrate. Each inoculum was added to replace 2 percent of the reactor
volume after the reactors had remained quiescent for one half hour and the
proper amount of supernatant withdrawn.
This study was carried out for 18 weeks. Table 3 gives the operational
characteristics and efficiency for the experimental and control reactors
during this portion of the study. In regard to feed concentrations and
efficiency, the results were quite similar to the 23-week study with
synthetic feed alone. The only major difference was the level of MLSS in
the reactors and the percent volatile content of this biomass. Due to the
addition of the soil extract and wastewater concentrate inert solids were
added to the system, decreasing the volatile content from about 66 percent
to 44 percent.
Figure 4 shows the CMT concentration of the effluent from each reactor
on a weekly average basis for the entire study period. Also shown is the
TOC concentration of the CMT reactor effluent. The control reactor's
effluent TOC values were very similar to the experimental effluent values.
As shown on Table 3 the average TOC values for both effluents, over the
entire study, were about the same. Also the effluent TOC values are similar
to those on Table 2 indicating the external inoculum procedure did not im-
pose a significant increase in organic loading on the reactors.
The pattern of CMT concentration in the experimental reactor effluent
was not very different than the pattern observed on Figure 3. After a
rapid increase at the start of the 20 mg/1 CMT feeding there was erratic
response followed by a declining concentration. At week #14 the effluent
concentration of the CMT experimental reactor stabilized to the background
levels of CMT in the control reactor effluent.
16
-------
0 TOC, EXPERIMENTAL
REACTOR I
CMT, EXPERIMENTAL
REACTOR (20 mg/l 1
CMT, CONTROL -
REACTOR
24 6 8 10 12 14 16 18
TIME, PROGRESSIVE WEEKS
FIGURE 4. CMT and TOC of Reactor Effluents with
Synthetic Feed and External Inocula
17
-------
TABLE 3. Efficiency and Operational Data for Synthetic Feed and
External Inoculum Reactors for a Period of 18 Weeks
Reactor
Average and Range
Efficiency Items
COD, mg/1
TOC, mg/1
SS , mg/1
NH4-N
Oxidized-N , mg/1
TKN, mg/1
TP , mg/1
Alkalinity, mg/1 as
CaCO
Control
Feed Effluent
160 16
148-176 10-29
79 6
70-87 3-14
2 2
1-10 1-3
2 0.1
1-3 0.1-0.3
0.1 37
0.1-0.4 23-59
42 1
34-48 0.1-2
13 13
11-14 10-15
190 54
171-243 30-83
CMT Experimental
Feed Effluent
157 19
151-164 14-29
79 8
69-84 5-13
2 2
1-8 1-3
2 0.1
1-3 0.1-0.3
0.2 34
0.1-0.4 25-39
40 1
35-45 0.1-2
13 12
11-14 10-15
189 57
165-245 34-76
Operational Items
pH, units
DO, mg/1
Temperature, C
MLSS, mg/1
MLVSS, mg/1
Volatile, Percent
F/M, g COD/g MLVSS/d
SRT, days
Hydraulic detention
Control Reactor
6.9-7.2
4.0
3.0-5.6
20.9
20.0-21.5
6,600
3,400-7,200
2,900
2,100-3,200
44
37-68
0.22
0.19-0.28
18
15-19
time, hr 6
CMT Experimental Reactor
6.9-7.3
3.8
3.0-5.0
20.7
20.5-21.5
6,600
3,200-7,300
2,900
2,100-3,800
44
37-67
0.22
0.17-0.33
19
18-19
6
18
-------
It was concluded that external inoculum of soil and wastewater micro-
organisms did not accelerate the acclimation time of the reactor biomass to
CMT degradation. CMT is a compound that requires adaptive enzyme formation.
Since the external inoculum furnished a source of heterogenous micro-
organisms, and the acclimation time was not shortened, apparently the
adaptive enzyme system for CMT degradation is not a common occurrence.
300 ml Continuous Flow Reactor Studies
To determine if the synthetic feed studies were as suitable as munici-
pal wastewater for biodegradation studies of this nature, and to observe
the degradation of higher concentrations of CMT, four small 300 ml reactors
were used.
One unit was fed continuously with synthetic feed containing 50 mg/1
CMT and the other was fed continuously with settled municipal wastewater
dosed with 50 mg/1 CMT. For each type feed a control reactor was operated.
The control feeds contained no CMT. The mixed liquor content of each
reactor was obtained from the CMT acclimated biomass developed in the 5.7 1
reactor study reported in the above section. The reactors were operated to
maintain about 2,000 mg/1 of MLVSS in each reactor. The F/M ratio was about
0.25 g COD/g MLVSS/d in each reactor. The hydraulic detention time was 6 hr.
Duration of the study was three weeks. Results are shown on Table 4. These
data show that there was no difference in the efficiency of biodegradation
of CMT when this substrate was in either synthetic or municipal wastewater,
and a CMT concentration of 50 mg/1 could be degraded.
The percent loss of CMT was calculated on actual effluent CMT values,
neglecting the background level of CMT in the control reactors effluents.
Since the CMT colorimetric assay is non-specific and variable, and the
concentrations observed in the effluents were low compared to feed concen-
trations, use of a corrected value would have no significant effect on the
efficiency values.
CMT Starvation to Determine Acclimation Stability
To determine if the induced enzyme system of CMT acclimated biomass was
a stable property two 300-ml reactors were used. The mixed liquor for each
reactor was acclimated biomass from the 20 mg/1 CMT study utilizing the
5.7 1 continuous flow reactors. One small reactor received synthetic feed
containing no CMT and the other received municipal wastewater containing
no CMT. These units were operated continuously on their respective CMT
free feeds for 28 days under operational parameters listed in Table 2.
At the end of this CMT starvation period CMT at a concentration of
20 mg/1 was reintroduced into each type feed. Table 5 shows CMT concentra-
tions for feeds and effluents for both type wastewaters and percent loss of
CMT for two weeks prior to CMT starvation, during the four-week starvation
period and after resumption of CMT dosing.
19
-------
TABLE 4. Degradation of CMT in Synthetic and
Municipal Wastewater Using 300 ml Reactors
CMT, mg/1
Progressive days
Reactor
Synthetic
Wastewater, 50 mg/1 CMT
Feed
Effluent
*
Percent Loss of CMT
Municipal
Wastewater, 50 mg/1 CMT
Feed
Effluent
*
Percent Loss of CMT
1
39
1.7
96
45
3.1
93
468
52 54 49
3.7 4.5 3.7
93 92 92
50 55 50
3.4 2.7 2.4
93 95 95
11
44
2.8
94
52
2.3
96
13
52
3.2
94
53
2.6
95
15
48
2.8
94
48
3.2
93
18
47
2.6
94
49
1.9
96
20
53
3.5
93
51
3.1
94
* Not corrected for background level of CMT in a synthetic wastewater
control effluent which averaged 0.3 mg/1 during this study.
**Not corrected for background level of CMT in a municipal wastewater
control effluent which averaged 0.8 mg/1 during this study.
Immediately upon re-introduction of CMT into each type feed the
response of the previously acclimated biomass in each reactor was rapid.
Very efficient degradation of CMT occurred during the first 24-hour period.
This was not an extreme test of adaptive stability since the sludge
retention time was about 17 days. The 4-week starvation period was only
1.6 times the sludge retention period and consequently a portion of the
original mixed liquor still existed in the reactors at the end of this time.
The studies did show that acclimated microorganisms could be deprived of
CMT for a considerable length of time and still retain the capacity to
degrade the substance upon subsequent exposure.
Carbon Adsorption Study
During the initial phase of the biological studies when it was not
clearly evident that CMT was biodegradable a preliminary screening for
carbon adsorption was conducted.
Various dosages of activated carbon were added to 20 mg/1 distilled
water solutions of CMT. Adsorptivity at pH 3, 7 and 9 was investigated.
20
-------
TABLE 5. Stability of Acclimated Biomass
for Biodegradation of CMT
Reactor
Synthetic
Wastewater
Feed
Effluent
Percent Loss of CMT*
Municipal
Wastewater
Feed
Effluent
Percent Loss of CMT*
Pre-starvation
Continuous feed,
20 mg/1 CMT
Starvation
Continuous feed,
no CMT added
Re-start CMT
Continuous feed
20 mg/1 CMT
CMT, mg/1
2 Week Average
21
1.3
94
20
1.7
92
4 Week Average
1.1
1.1
1.3
0.6
Progressive days
127 14
20 20 20 20
1.4 0.5 1.4 0.9
93 97 93 96
20 20 20 20
2.8 2.5 1.7 1.8
86 87 92 91
*Not corrected for background CMT values.
The solution at pH 3 showed over 90 percent removal of CMT at the
various carbon dosages. At pH values of 7 and 9 the carbon adsorption was
not efficient, and even at high carbon dosages the removal of CMT did not
exceed 50 percent.
Detailed data is given in Appendix B.
21
-------
SECTION 5
DISCUSSION
These studies on CMT biodegradation were conducted to reflect usual
operating parameters controlled in activated sludge treatment. Under this
set of conditions CMT was shown to be biodegradable; however, it was
determined that a rather protracted induction period was necessary before
the adaptive enzyme system for efficient oxidation was obtained.
Once acclimation of the biomass occurred, the stability of the system
was compatible with the expected occurrence of CMT in municipal wastewater.
Acclimation was shown to be retained for a period of 1.6 times the SRT of
the biomass. If CMT were introduced into municipal wastewater as a substi-
tute for phosphates in detergent formulations, the material would occur as
a continuous constituent of wastewater. Once the municipal biological
system acclimated to the presence of CMT a continual high efficiency of
degradation would be expected.
The formulation of synthetic wastewater used in these studies was
shown to be a suitable substitute for determination of biodegradation in
comparison with municipal wastewater.
The pattern of adsorption of CMT by activated carbon at the several pH
values is consistent with the chemical structure shown in Table 1. At pH 3
the compound would be in the unionized carboxylic acid form and have
greater affinity for carbon adsorption than when it is ionized at the more
alkaline pH values.
Since municipal wastewaters usually have pH values near 7 the use of
activated carbon for removal of CMT would not be practical.
22
-------
REFERENCES
1. Detergent Phosphate Ban Review. U.S. EPA Region V, Chicago, 111., 56 pp.
February (1977).
2. Pollard, R. R., "Amino Acid Chelating Agents in Detergent Applications."
Soap and Chem. Specialities, 42, 9, 58 (1966).
3. Bunch, R. L. and M. B. Ettinger, "Biodegradability of Potential Organic
Substitutes for Phosphates." Proc. 22nd Industrial Waste Conference,
Purdue University, Ext. Series 129 (1967).
4. Bunch, R. L., and C. W. Chambers, "A Biodegradability Test for Organic
Compounds." Journal Water Pollution Control Federation, 39, 181 (1967).
5. Lamberti, V., M. D. Konort, and I. Weil, Lever Brothers Co., U.S. Patent
3, 692, 685. (1972).
6. Chem. Engr. p. 25, (July 21, 1975).
7. Household and Personal Products Ind., p. 16, (August 1975).
8. Builder M. Information Bulletin. Monsanto Chemical Company. St. Louis,
Mo., 23 pp. (October 1975).
9. Ludzak, F. J., "Laboratory Model Activated Sludge Unit." Journal Water
Pollution Control Federation, 32, 605 (1960).
10. McKinney, R. E., and J. M. Symons, "Bacterial Degradation of ABS." I.
Fundamental Biochemistry. Sewage Ind. Wastes, 31, 549-556 (1959).
11. Weinberger, L. W., "Nitrogen Metabolism in the Activated Sludge Process."
Sc.D. Thesis, Massachusetts Institute of Technology, Cambridge, MA (1949),
12. Huddleston, R. L., and R. C. Alfred, "Evaluation of Detergents by Using
Activated Sludge." Journal American Oil Chem. Soc., 41, 732-735 (1964).
13. Husmann, W., F. Malz, and H. Jendreyko. "Removal of Detergents from
Wastewaters and Streams." Forschungsber. Landes Nordhein-Westfalen
No. 1153 (1963).
14. Lashen, E. S., F. A. Blankenship, K. A. Booman, and J. Dupre, "Biodegra-
dation Studies on a p-t-octylphenoxypolyethoxyethanol." Jour. Amer. Oil
Chem. Soc., 43, 371-376 (1966).
23
-------
15. Nelson, J. F., R. E. McKinney, J. H. McAteer, and M. S. Konecky.
"Biodegradability of ABS." Develop. Ind. Microbiol., 2_, 92-101 (1961).
16. Fitter, P., and J. Trauc. Synthetic Surfactants in Wastewaters. IV.
"Biodegradation of Nonionic Agents in Laboratory Models of Aeration
Tanks." Sb. VSChT, 7^(1), 201-216 (1964).
17. Schonoborn, W. "Methods for Testing Biodegradability of Detergents."
Seifen-Ole-Fette-Wachse, 88, 870-875 (1962).
18. Urban, P. J., G. J. Stander, D. W. Osborn, P. F. Theron, and S. M.
Walker. "Experiments to Establish the Degradability of a New Biologically
Soft Detergent." CSIR Research Report 231, South African Council for
Scientific and Industrial Research, Pretoria, (1965).
19. Gray, P. H. H., and H. G. Thornton. "Soil Bacteria That Decompose Certain
Aromatic Compounds." Zentr. Bakteriol. Parasitenk, Abt. II, 73, 74-96
(1928) .
20. Butter field, C. T., C. C. Ruchhoft, and P. D. McNamee. Studies on Sewage
Purification. V. "Biochemical Oxidation by Sludges Developed by Pure
Cultures of Bacteria Isolated from Activated Sludge." Sewage Works J.
9, 173-196 (1937).
21. Cordon, T. C., E. W. Maurer, O. Panasiuk, and A. J. Stirton. "Analysis
for Sulfate Ion in the Biodegradation of Anionic Detergents." Jour.
Amer. Oil Chem, Soc., 45, 560-562 (1968).
22. German Government. Ordinance on the Degradability of Detergents in
Washing and Cleaning Agents. Bundesgesetzblatt (Bonn) Part I, No. 49,
698-706 (12 Dec. 1962).
23. Biodegradation Subcommittee. The Status of Biodegradability Testing
of Nonionic Surfactants. Jour. Amez. Oil Chem. Soc., 46, 432-440
(1969).
24. Standard Methods for the Examination of Water and Wastewater. American
Public Health Association, 1015 Eighteenth Street NW, Washington, D.C.
20036. Thirteenth Edition (1971).
25. Vicarro, J. and E. Ambye, "Colorimetric Assay for Carboxymethyloxy-
succinate." Jour. Amer. Oil Chem. Soc., 50, 213-217 (1973).
24
-------
APPENDIX A
ANALYTICAL METHODS
Two analytical methods were used to monitor CMT (also referred to as
"Builder M"); a colorimetric method which is simple and fast, but non-
specific and subject to minor interferences; and a gas chromatographic (GC)
method which is specific, but time consuming and cumbersome. For daily
monitoring of the fate of CMT the colorimetric method was used exclusively.
Once a week, however, samples were also analyzed gas chromatographically
for comparison of results by both methods.
The "Builder M" used in this investigation contained only 78 percent
CMT; however, all calculations were based on 100 percent purity.
Colorimetric Method
Except for minor modifications this method is the same as one reported
by Viccaro and Ambye (25) for the analysis of carboxymethyloxysuccinate.
This method is based on the hydrolysis of CMT to produce glycolic acid,
which in turn yields formaldehyde in the presence of high concentrations of
sulfuric acid, g-naphthol condenses with formaldehyde to form highly colored
diarylamines and the intensity is proportional to the quantity of CMT in the
sample. A detailed description of the method is given later in Part I of
this Appendix.
A thorough shakedown of the method was made before the biodegradation
study was initiated. Several samples of distilled water, tap water,
secondary effluent, and raw wastewater were dosed with various quantities of
CMT up to 20 mg/1 and assayed. Linear and consistent responses were
obtained on all samples except those made up in distilled water. This
unusual problem was circumvented by using tap water for reference and
standard preparations. It is suspected that the erratic results obtained
with distilled water were due to the absence of ions which may stabilize
the colored end product.
As with many colorimetric methods occasional erratic results even on
duplicate samples were experienced. Fluctuations in the measured CMT
content of the same feed, and the apparent lack of significant biodegra-
dation on CMT after ten weeks of exposure raised some doubts about the
reliability of this method. A thorough check of the method, jointly by
personnel from this laboratory and a visiting chemist from Monsanto
Chemical Company, was made early in September 1978. A total of thirty-four
standard and experimental samples were assayed independently by both
25
-------
laboratory personnel. The results obtained were remarkably close to one
another on all samples, thus reaffirming confidence in the method and its
suitability for this study.
Interferences with the CMT analysis seldom exceeded 2 mg/1 in the raw
and 1.0 mg/1 in the secondary effluent. These are suspected to be due to
glycolic acid and acetaldehyde among many other possible interfering compo-
nents found in wastewater. In view of this, coupled with experimental
errors, any quantity of 2 mg/1 or less should be viewed with uncertainty.
Gas Chromatographic Method
This unpublished method was developed by C. B. Warren of Monsanto
Chemical Company. It is based on esterification of CMT with n-propyl
alcohol and subsequent analysis by GC. A detailed description of the GC
procedure including the esterification step is given in Appendix A, Part II.
Experiments with raw wastewater and secondary effluent dosed with
several concentrations of CMT produced linear response. However, plots of
the detector response versus CMT concentration shifted with different
experiments though no interferences were noted in any raw wastewater or
secondary effluent. Also, identical samples of a CMT reference standard
solution analyzed routinely with authentic samples, occasionally produced
inconsistent results. These anomalies are suspected to be due to an
occasional incomplete esterification of the CMT. Despite these shortcomings
sufficient data were gathered to indicate when biodegradation of the CMT
started, and to verify the reliability of data obtained by the colorimetric
method.
Comparison of Analytical Methods
A total of sixty-six parallel analyses were made by both the colori-
metric and the GC methods using samples of feed and effluent of the
fermenters. In forty-six of these analyses agreement within +_ 25 percent
was obtained by both methods; the remaining twenty analyses exceeded this
limit. The seemingly wide margin of error and the high incidence of
"disagreement" of results by both analytical methods are not considered
excessive in view of the several critical steps in the esterification
process of the gas chromatographic samples, combined with the usually large
experimental errors of non-specific colorimetric methods. Results on
comparative samples for an effluent from a reactor receiving synthetic
wastewater and 20 mg/1 CMT are shown on Figure A-l.
Repeated analyses of identical samples of 20 mg/1 standard solution
of CMT by the GC method often produced results far more inconsistent and
erratic than comparable analyses by the colorimetric method. Consequently,
the utility of the GC method was limited to checking the patterns of the
GC results versus the colorimetric results. These patterns were reasonably
parallel particularly once biodegradation of the CMT began to occur.
26
-------
SYNTHETIC WASTEWATER
25-1
20-
H 15-|
U
EFFLUENT BY GC
METHOD-•
O>
E
10-
5-
\A
\ EFFLUENT BY
\~" COLORMETRIC
« METHOD- A
^^^^~i i ~T " "i ~ i ^^^~T i i ( i i^"™ i ™~""" ~ T^^^^^^^^^™
1 3 5 7 9 11 13 15 17 19
PROGRESSIVE WEEK
Figure A-l. Comparative Analytical Methods
for CMT in Reactor Effluent
27
-------
APPENDIX A, PART I
Colorimetric Assay for Carboxymethyltartronate
Reagents:
92.5% Sulfuric Acid: Add 100 ml concentrated sulfuric acid (95.5-96.5%)
to 7 ml distilled water.
80% Sulfuric Acid: Add 100 ml concentrated sulfuric acid to 37 ml
distilled water, cool to room temperature.
3-Napthol Reagent: Weigh out 50 mg of reagent grad 3-Napthol and
transfer into 100 ml volumetric flask. Add 75 ml of 92.5%
sulfuric acid and allow 1 hour for complete dissolution of
the 3-Napthol crystals, and dilute to 100 ml with 92.5% sulfuric
acid. When not in use, store in dark cool place. This reagent
is stable for up to four days if refrigerated.
3:1 Hydrochloric Acid: Add 75 ml of concentrated hydrochloric acid
to 25 ml of distilled water.
Procedure:
One ml sample (unfiltered) is placed in a test tube and 0.1 ml of 3:1
mixture of HCl is added. Place in an oven maintained at 105° for 18-20
hours (overnight) , remove from the oven and allow to cool to room
temperature. Add 1 ml of 3-Napthol solution, mix vigorously for one
minute on a vortex mixer and return to the same oven for one hour.
Allow to cool and add exactly 3 ml of 80% sulfuric acid, mix thoroughly.
Allow the sample to stand at room temperature for twenty minutes and read
the absorbance at 480 nm using distilled water in the reference side
of the spectrophotometer.
A reagent blank and 1 ml sample of standard solution containing 20 mg/1
CMT are assayed along with the authentic samples for reference.
Calculations:
Subtract the blank absorbance from the standard and sample absorbances
and proceed as follows.
mg/1 CMT = corrected sample absorbance x ^ ±n gt& (2Q /1}
in sample corrected std absorbance
28
-------
APPENDIX A, PART II
Gas Chromatographic Assay for Carboxymethyltartronate
Reagents:
1-propanol, trifluoracetic acid, acetyl chloride, 1,2-dichloroethane,
tetracosane (C-24), Freon 113 (1,1,2-trichlorotrifluorethane, b.p.
47°C).
Solutions:
Propanol-HCl: Slowly add, with rapid stirring, 20 ml of acetyl chloride
to 70 ml of ice bath cooled propanol contained in a 250 ml Erlenmeyer
flask. The solution is then adjusted to 100 ml with propanol.
Tetracosane solution: A final solution of 5 mg/1 of tetracosane (C-24)
in 1, 2-dichlorethane is prepared from appropriate stock solutions.
A more concentrated final solution will interfere with the CMT
analysis. C-24 is used as a marker to identify CMT in the chromatogram.
Derivatization:
1 ml sample (unfiltered) is placed in a 150 x 15 mm test tube, freeze
dried, and an internal standard of 1.0 mg of tetracosane (0.004 ml of
final reagent solution) is added. 0.5 ml of trifluoracetic acid was
also added to remove nitrite interference. The tube is shaken
vigorously on a vortex mixer for one minute and placed in a 65°C water
bath to help dissolve all of the residue. The test tube is then placed
in a 70°C water bath and the trifluoracetic acid stripped off with a
stream of nitrogen; 2.0 ml of propanol-HCl solution was added, warmed
to 65°C and mixed vigorously on the vortex mixer for one minute, and
placed in a 65°C water bath for thirty minutes to esterify the CMT.
The test tube is then placed in a 70°C water bath and the propanol-HCl
solution is stripped off with a stream of nitrogen. The residue is
dissolved into 2 ml of Freon 113 and transferred into a 5 ml graduated
centrifuge tube. One subsequent washing of the test tube with 1 ml
of Freon 113 is recommended, with the addition of the wash solution
into the centrifuge tube. The final volume of the Freon solution is
adjusted to 1.0 ml using nitrogen to strip off the excess Freon.
A standard CMT solution containing 20 mg/1 of CMT should be analyzed
with the experimental samples for reference and calibration of the gas
chromatograph.
29
-------
Analysis:
0.005 ml samples of the final Freon solution were analyzed on a Perkin-
Elmer Model 3920 gas chromatograph equipped with a dual flame ionization
detector system. The column was 0.91 m x 3.2 mm stainless steel packed
with Talsorb (0.65% ethylene glycol adipate on heat treated acid washed
chromosorb W) available from Regis Chemical Company, Morton Grove,
Illinois. The oven temperature was programmed from 80°C to 220°C at
16°C/minute. Nitrogen carrier gas was used at a flow rate of 25 ml/minute.
The CMT emerged from the column after 7.4 minutes followed by tetracosane
(C-24) at 7.7 minutes. Though the retention times of the two peaks were
close, their resolution was excellent as shown in Figure A-2.
For calculating sample content CMT, the peak height was compared with
the corresponding peak of a standard solution processed through the
entire procedure at the same time the unknowns were determined.
30
-------
n
BLANK
C-24-
iu
tn
z
o
Q.
CO
UJ
oc
oc
UJ
Q
OC
§
OC
20 mg
STANDARD
CMT
C-24
CMT-
SAMPLE
FEED
C-24-*
CMT-
80480
RETENTION TIME IN MINUTES
8
Figure A-2. Resolution of CMT by Gas
Chromatography
31
-------
APPENDIX B
REMOVAL OF CMT BY CARBON ADSORPTION
The adsorption of CMT by activated carbon was investigated at pH 3, 7
and 9 using five different doses of carbon and a blank. Distilled water
spiked with 20 mg/1 CMT was used in this experiment.
The carbon, Calgon Filtrasorb 200 (200/400 mesh) was stirred magnetic-
ally for one hour into 1 liter samples of spiked water contained in 2-liter
beakers, filtered and the filtrate subsequently analyzed for CMT by colori-
metric analysis. Table B-l gives the residual CMT (C_) and the percent
removal. Figure B-l shows the removal efficiency as a function of carbon
dosage for the three pH levels tested.
Maximum CMT removal was obtained at an impractical pH 3 value. At pH 7,
which would be typical for wastewater, the removal rate ranged only from
12-50% for the various carbon doses; and at pH 9 the removal efficiency
declined further to a range of 15-36%. Thus it appears that carbon treatment
for the removal of CMT on a full plant scale basis would be unrealistic.
32
-------
TABLE B-l. Carbon Adsorption of CMT
Carbon
Dose
mg/1
0
200
400
600
800
1000
Distilled Water With 20 mg/1 CMT Added
pH = 3
Percent
C_ C - C_ Removal
f of
25.3
2.4 22.9 91
1.4 23.9 94
1.3 24.0 96
0.5 24.8 98
0.2 25.1 99
pH = 7
Percent
C_ C - C_ Removal
f o f
22.4
18.6 3.8 17
19.8 2.6 12
14.6 7.8 35
14.4 8.0 36
11.3 11.1 50
pH = 9
Percent
C_ C - C_ Removal
f of
20.3
15.7 4.6 23
17.2 3.1 15
15.5 4.8 24
12.9 7.4 36
15.6 4.7 27
w
w
-------
100
u
y. 80
o
60
o—o pH-3
D—a pH-7
x—x pH-9
0 40
Of.
20
200 400 600 800
mg/l CARBON DOSAGE
Figure B-l. Carbon Adsorption of CMT
at Various pH Values
1000
34
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
i. REPORT NO.
EPA-600/2-78-115
2.
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
BIODEGRADATION STUDIES OF CARBOXYMETHYL TARTRONATE
5. REPORT DATE
July 1978 (Issuing Date)
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S).
UTHOR(S)
E. F. Earth, H. H. Tabak and C. I. Mashni
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Municipal Environmental Research Lab.-EPA
Wastewater Research Division, TPBD, BTS
26 W. St. Clair St.
Cincinnati, Ohio 45268
10. PROGRAM ELEMENT NO.
1BC6117 SOS #3, Task A/04
11. CONTRACT/GRANT NO.
In-house Report
12. SP.ONSORING-AGENCY NAME AND.AD.DRESS
Municipal Environmental Research Laboratory—Cin.,OH
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
13..
PERIOD COVERED
14. SPONSORING AGENCY CODE
EPA/600/14
15. SUPPLEMENTARY NOTES
Project Officer: Edwin F. Earth, (513) 684-7641
16. ABSTRACT
Carboxymethyi tartronate (CMT) was shown to be biodegradable in bench-scale
activated sludge reactors.
After initial exposure to CMT in continuous flow systems an acclimation
period of 14 weeks was necessary before efficient degradation occurred.
Once acclimated to CMT the biomass could be starved in regard to this substrate
for at least 1.6 times the sludge age and still retain capacity to degrade the
material upon re-introduction.
Activated carbon was not found to be effective for CMT removal at a pH
value of 7.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
COSATI Field/Group
Activated Sludge
Acclimation*
Biodeterioration
Phosphate replacement
Continuous flow reactors
13B
18. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY CLASS (ThisReport)
Unclassified
21. NO. OF PAGES
43
20. SECURITY CLASS (Thispage)
Unclassified
22. PRICE
EPA Form 2220-1 (Rev. 4-77)
35
* U.S. GOVBWUEHTKlimiKeofnCi 1978— 757-140/1441
------- |