Treatment Of MTBE Using Fenton's Reagent

EPA/600/JA-00/193
2000
TREATMENT OF MTBE USING FENTON'S REAGENT

Asim B. Ray and Ariamalar Selvakumar
U.S. Environmental Protection Agency
National Risk Management Research Laboratory
Water Supply and Water Resources Division
Urban Watershed Management Branch
Edison, New Jersey
ABSTRACT
This paper addresses the removal of MTBE from water, using Fenton's Reagent.
Although complete mineralization of MTBE by Fenton's Reagent was not achieved, greater than
99% destruction of MTBE was realized. This was accomplished at a Fe+2:H2O2 ratio of 1:1 and
one hour of contact time. In all tests, twice the stoichiometric ratio of H2O2 to MTBE was used.
The major byproducts were tertiary butyl alcohol, tertiary butyl formate, and acetone with traces
of 2-methyl-l-propene (isobutene). While small quantities of O2 evolved, no significant quantity
of CO2 gas was detected.

INTRODUCTION

Several oxygenates have been used in the United States since the 1970's as octane-
enhancing replacements for lead tetraethyl. These include ethanol, methanol, ethyl tertiary butyl
ether (ETBE), and tertiary butyl alcohol (TEA) as well as the currently controversial methyl
tertiary-butyl ether (MTBE). Addition of MTBE to gasoline improves fuel combustion and
reduces the resulting concentrations of carbon monoxide and unburnt hydrocarbons. The use of
MTBE in gasoline at levels in excess of 10% by volume began in November 1992 when the
requirements of the 1990 Clean Air Act Amendments (CAAA) mandated the use of oxygenated
gasoline during the winter to help meet standards for carbon monoxide emissions. Furthermore,
since January 1995, the CAAA also required nine metropolitan areas that have the most severe
ozone pollution to use, year-round, reformulated gasoline that contains fuel oxygenates.
Currently MTBE is added to about 30% of gasoline nationwide at an average concentration of
about 11% by volume (USEPA, 1994). Since 1993, MTBE has been the second most produced
organic chemical manufactured in the United States (USEPA, 1998). MTBE is the most
commonly used fuel oxygenate because of its many favorable properties such as low production
cost, ease of production, high octane rating, and favorable transfer and blending characteristics
(Ainsworth, 1992; Shelly andFouhy, 1994).

Unfortunately, the increased production and physical properties of MTBE have led to its
introduction into the environment. It has been detected both in ground and storm waters. In a
recent survey by the United States Geological Survey (USGS), MTBE was detected in 27

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percent of the 210 wells and springs sampled, but none was found in drinking water wells
(Squillace et al., 1996). Measurable concentrations of MTBE were also found in some of 592
storm water samples collected by the USGS in 16 cities and metropolitan areas required to
obtain National Pollutant Discharge Elimination System (NPDES) permits (Delzer et al., 1996).

       Physical and chemical properties of MTBE control its fate in the environment. MTBE,
molecular weight 88, is a colorless liquid aliphatic ether with a characteristic odor. It gives
water an unpleasant taste and odor at only a few tens of microgram per liter (|ig/L). It is highly
soluble in water (about 48,000 mg/L) and has a low octanol-water partition coefficient (log Kow ~
1.24).  Therefore, MTBE is highly mobile,  undergoing little or no retardation as it travels
through a groundwater system.  Because of its very low Henry's Law Constant (0.022 at 25
degrees Celsius), almost 1/1 Oth of benzene, it is difficult to remove MTBE from aqueous streams
by air purging. It is resistant to biological degradation with a degradation half life of 10,000
days (27 years). Laboratory studies have shown that MTBE is resistant to all forms of aerobic as
well as anaerobic biodegradation, key components in the natural attenuation process (Vance,
1998).

       The U.S. Environmental Protection Agency (USEPA) has tentatively classified MTBE as
a possible human carcinogen, but no drinking water regulation has yet been promulgated for
MTBE (USEPA, 1997). However, a drinking water advisory of 20 to 40 |ig/L to avoid
unpleasant taste and odor effects has been issued. This advisory concentration provides a large
margin of safety for non-cancer effects and is in the range of margins typically maintained for
potential  carcinogenic  effects (Squillace et al., 1998).

       In July 1999, a USEPA  advisory panel called for a  substantial reduction in the use of
MTBE as a gasoline additive and recommended that Congress remove the current requirement
that 2% of reformulated gasoline by weight consist of oxygen - a mandate of the 1990 CAAA
(Grisham, 1999).

       MTBE's high solubility in water and recalcitrant characteristics make it difficult to
remove from impacted water by conventional treatment technologies such as granular activated
carbon (GAC), air stripping, or biological treatment. Previous research has demonstrated that
Fenton's  Reagent, a combination of hydrogen peroxide and ferrous sulfate, can effectively
mineralize pure MTBE in water (Chen et al., 1995). Fenton's Reagent generates hydroxyl
radicals, which are second only to fluorine  in oxidation potential, and are capable of nonspecific
oxidations (Bull and Zeff, 1992).  The following equations represent the formation of hydroxyl
radicals and complete oxidation of MTBE by Fenton's Reagent:

       Fe(aq)+2 + H2O2   	  Fe(OH)(aq)+2 + OH" 	(1)

       C5H12O + 15 H2O2	  5 CO2 + 21 H2O       	(2)

Under the sponsorship of USEPA's National Risk Management Research Laboratory (NRMRL),
a bench-scale study was conducted by Battelle (Contract No. 68-C7-0008, Work Assignment

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No. 1-11) to evaluate the use of Fenton's Reagent for treatment of MTBE in water.

EXPERIMENTAL METHODS

Materials

All chemicals used were obtained from Aldrich Chemical, Inc. and of ACS analytical
grade or better. All solutions were prepared in deionized water (Millipore). All glasswares were
rinsed, sequentially, with Alconox™ cleaning solution, 10% nitric acid, tap water, methanol, and
deionized water (DI).

Stock solutions of acetone, MTBE, and tertiary butyl formate (TBF) each at 5,000 mg/L,
and 1,000 mg/L of TEA were prepared in DI water. The stock solutions were stored in
aluminum foil wrapped-volumetric flasks at 4°C. Calibration standards were prepared by serial
dilution of the stock solutions.

Test samples for MTBE degradation studies were prepared from appropriate stock
solution immediately before use.

A 5% H2O2 solution was prepared by diluting 50% H2O2by DI water. Ferrous sulfate
solution for Fenton's Reagent was prepared by dissolving FeSO4.7H2O solids in DI water.

Bovine catalase (Sigma) was used as received to help decompose excess H2O2.

Analytical Procedure

Aqueous samples were analyzed (EPA 5021) with a Tekmar 7000 Headspace Analyzer™
equipped with a Varian Star 3400CX gas chromatography (GC) (Supelco SPB-1 60 meter long,
0.53 mm inside diameter, and 3.00 • m film fused silica capillary column) with a flame ionization
detector (FID) and an auto-sampler. Samples were heated to 95°C for 55 minutes, agitated for 2
minutes, purged with helium into the GC column held at 35°C. With a 2-minute hold, the GC
oven was programmed at 8°C/min to 150°C, then 10°C/min to 200°C.

A five-point calibration with concentrations of 0.5, 1, 5, 10, and 50 mg/L was performed
for MTBE and TEA analyses. Triplicate samples were run for MTBE and TEA calibrations. A
three-point calibration with 0.5, 1, and 5 mg/L was performed for acetone and TBF analyses.
Duplicate samples were run for the acetone and TBF calibrations.

H2O2 was analyzed using the Lamotte titration kit HP-5; residual H2O2 after the reaction
was determined using the Lamotte Octet Comparator test kit HP-40 after quenching with bovine
catalase. Iron was determined using the Hach test kit following Standard Method 3500-Fe D.

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For organic byproduct analysis, samples of the solution collected during the tests were
analyzed by GC/mass spectrography (MS). The GC/MS consisted of a Hewlett-Packard (HP)
GC with an HP 5970 mass selective detector and a Supelco SPB-1 column operating in full scan
mode. In this mode, the mass spectrometer scanned all masses continuously between m/z 30 and
m/z 300. Sample vials each containing 2-mL aqueous sample were heated in an oven to 60°C for
30 minutes. A sample was taken from the headspace of each vial and immediately injected into
the GC/MS. Byproducts in the form of tentatively identified compounds (TICs) were confirmed
using the National Bureau of Standards (NBS) data base. After by-products were identified by
GC/MS, individual pure compounds were injected into the GC/FID and GC/MS for further
confirmation of their retention times and mass spectra. After confirmation by both GC/MS and
GC/FID, these compounds were calibrated on the GC/FID and quantified. Retention times of
MTBE and associated byproducts are given in Table 1.

For gas analysis, the samples were analyzed using an SRI GC equipped with a CTRI
concentric column connected to a thermal conductivity detector (TCD).

Experimental Setup

Figure 1 shows the schematic diagram of the experimental apparatus used in this study.
It consisted of a three-neck, 500-mL round bottom flask fitted with a pH meter, a sampling
syringe, and a gas sampling assembly. The pH probe was inserted through one of the side necks
into the test solution. The other side neck was fitted with a gas collection assembly consisting of
a sampling port and a graduated burette designed to measure the volume of gas produced during
the reaction. The center neck was fitted with a long needle syringe inserted through the septum.
The needle was used to introduce nitrogen gas (N2) for flushing the reactor, to inject H2O2 to
begin the reaction, and to withdraw solution samples for chemical analyses. A magnetic stirrer
was used to mix the test solution throughout the experiment.

Experimental Procedure

Four experiments were conducted to accomplish the following three objectives:

1. identify and optimize operational parameters for treating MTBE contaminated
water using Fenton's Reagent;
2. determine the percent destruction of MTBE; and
3. identify and quantify the possible reaction products.

Test conditions are tabulated in Table 2. For all tests, H2O2 was added at two times the
stoichiometric amount required for complete mineralization of MTBE (Eq. 2). The amount of
ferrous sulfate added varied with each test and corresponded to the specific H2O2:Fe ratio.

For each test, 500 mL of MTBE test solution and a known amount of ferrous sulfate solid
were quickly added to the flask through the center neck. After sealing the center neck with the
septum, the solution was stirred until the ferrous sulfate solid was completely dissolved. The

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tubing connected to the graduated burette was lifted up to bring the water level in the burette
close to the top to minimize the head space in the burette. The valve at the bottom of the burette
was then closed and the venting valve in the top of the burette was opened. The reactor was then
flushed with ultra-pure N2 gas through the syringe for about 20 minutes. Subsequently, the
burette valve was opened and the venting valve was closed. The water level in the burette was
pushed down to the bottom of the burette before the valve on the N2 gas cylinder was turned off.
A 10-mL gas mixture sample and a 10-mL aqueous sample were collected and then a known
amount of H2O2 was injected into the reactor to initiate the reaction. The reactor was sampled at
time intervals following the initiation of the reaction.

Liquid samples were collected from the reactor vessel from the center neck using a glass
syringe fitted with a 4-inch long needle. The sample was placed in 20-mL glass sample vial
containing 5 drops of bovine catalase, which terminated the reaction by decomposing excess
H2O2. Two 2-mL subsamples were transferred into two 20-mL auto-sampler vials, each
containing 0.5 g NaCl, for duplicate head space analysis of MTBE by GC/FID. At the end of
each test, the amount of H2O2, total Fe, and Fe2+remaining in the solution were measured. H2O2
was measured using a titration kit and iron was measured using Hack test kits.

Gas samples were collected from the gas sampling port using a 10-mL gas-tight syringe
that was flushed twice with helium prior to use. Before the syringe was removed from the
sampling port, the tubing connected to the burette was lifted to equalize water levels in the
tubing and in the burette. The burette reading was recorded before and after each sampling event
to calculate the volume of gas produced. Gas samples were analyzed for oxygen and carbon
dioxide using a GC.

RESULTS

The results of each test are summarized in Tables 3 through 6. During all tests, the
solutions in the reactor (containing MTBE and Fe+2) turned yellow and turbid immediately after
the addition of H2O2, indicating the formation of iron precipitates. The pH values of the
solutions dropped rapidly after H2O2 addition. Concentrations of MTBE decreased rapidly but
stabilized within 5 minutes, indicating fast degradation kinetics (Tests #3 and #4). MTBE
degradation products, 2-methyl-1-propene (C4H8), acetone, TEA, and TBF were identified in all
samples collected during the tests. But the amounts of gases produced during these tests were
not quantified. Although some O2 was evolved, no detectable quantity of CO2was found.

Effects of H2O2:Fe+2 ratios on MTBE reduction, after 60 minutes of reaction, are shown
in Table 7. Percentage reduction of MTBE of > 99, 97, 66, and 0 were achieved at H2O2:Fe+2
ratios of 1:1, 6:1, 10:1, and 100:1, respectively. As the Fe+2 dose increased (i.e., the H2O2:Fe+2
ratio was decreased), the percentage of MTBE degradation also increased.

CONCLUSIONS

Oxidation of MTBE showed that the main reaction products were: acetone, TEA, and

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TBF. Small quantities of 2-methyl-l-propene (isobutylene) (C4H8), a gas of molecular weight 56
and insoluble in water, were found, but due to their small quantities were not quantified. Also,
no CO2 was observed. Quantities of oxygen evolved were also minimal. These results indicate
that the degradation of MTBE by the classical Fenton's Reagent as represented by the equation:
C5H12O +15 H2O2 • *5CO2 + 21 H2O was not realized under the experimental conditions of this
study.

In these oxidation reactions, the amounts of MTBE used were at or below 21 mg/L.
Even at these low concentrations, under optimum reaction conditions, the residual concentrations
of MTBE, after 1 hour of contact, were below 2 mg/L. These results show that Fenton's Reagent
can reduce the concentrations of aqueous MTBE well below the regulated limit. Other important
findings of the study are:

1. The optimum ratio (molar) of H2O2to Fe appears to be 1:1. At this ratio more than 99%
removal of MTBE was achieved at a contact time of only one hour. This ratio of
hydrogen peroxide to iron is the recommended ratio for preparing Fenton's Reagent and
it is no surprise that the highest reduction of MTBE was achieved at this ratio.

The classical Fenton's reaction consists of following steps:

Fe+2 + H2O2 • «Fe+3+ OH''+ OH"
Fe+3 + H2O2 • «Fe+2 + H+ + HO2"
Fe+3 + HO2"« «Fe+2 + H+ +O2

These equations explain why a large excess of either iron or hydrogen peroxide does not help in
the destruction of MTBE.

2. After one hour of contact, the initial pH of the mixtures dropped from about 5 to 3
signifying the formation of organic acids. The formation of TBF supports this
contention.

A cursory look at the results of the two tests (#1 and #4) which gave high percentage of
MTBE removal, showed that input of MTBE (as carbon) and the products (calculated as carbon)
do not match. As a matter of fact, close to 80 and 60 percent of the product were missing for
Tests 1 and 4, respectively (Table 8). This may be due to the formation of some volatile
products which are escaping the reaction system or the generation of some nonvolatile organics,
for example, formic and/or acetic acids.

In an ongoing study (Contract No. 68-C98-157, Work Assignment No. 0-2), an attempt
will be made to resolve these unanswered questions.

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REFERENCES

Ainsworth, S. 1992. "Oxygenates Seen as Hot Market by Industry." Chemical Engineering
News.  Vol. 70, pp. 26-30.

Bull, R.A. and J.D. Zeff.  1992. "Hydrogen Peroxide in Advanced Oxidation Processes for
Treatment of Industrial Process and Contaminated Groundwater." Proceedings of the First
International Symposium, Chemical Oxidation: Technologies for the Nineties, Nashville,
Tennessee. February 20-22.

Chen, C.T., A.N. Tafuri, M. Rahman, M.B. Forest, E. Pfetzing, and M. Taylor.  1995.
"Oxidation of Methyl-t-Butyl-Ether (MTBE) Using Fenton's Reagent." Proceedings of the 88th
Annual Meeting of the Air and Waste Management Association, 95-WA91.03.  San Antonio,
Texas, June 18-23.

Delzer, G.C., J.S. Zogorski, TJ. Lopes, and R.L. Bosshart. 1996.  "Occurrence of the Gasoline
Oxygenate MTBE and BTEX Compounds in Urban Stormwater in the United States, 1991-
1995." U.S.  Geological Survey Water Resources Investigation Report 96-4145, 6 p.

Grisham Julie. 1999.  "Cutting Back MTBE." Chemical and Engineering News. August 2.

Shelley, S. and K. Fouhy.  1994. "The Drive for Cleaner Burning Fuel." Chemical Engineering.
Vol. 101, No. 1, pp. 61-63.

Squillace, P.J., J.S. Zogorski, W.G. Wilber,  and C.V. Price.  1996. "Preliminary Assessment of
the Occurrence and Possible Sources of MTBE in Groundwater in the United States, 1993-
1994." Environmental Science and Technology, Vol. 30, No. 5, pp.  1721-1730.

Squillace, P.J., J.F. Pankow, N.E. Korte, and J.S. Zogorski.  1998. "Environmental Behavior and
Fate of Methyl tertiary-Butyl Ether (MTBE)" U.S. Geological Survey Fact Sheet FS-203-96.

U.S. Environmental Protection Agency.  1994.  "Health Risk Perspectives on Fuel Oxygenates."
EPA/600/R-94/217. Office of Research and Development, Washington, D.C.

USEPA.  1997. "Drinking Water Advisory: Consumer Acceptability Advice and Health Effects
Analysis on Methyl tertiary-Butyl Ether (MTBE)." EPA 822-F-97-008.  Office of Water,
Washington, D.C.  December.

USEPA.  1998. "MTBE Fact Sheet #3: Use and Distribution of MTBE and Ethanol." EPA 510-
F-97-016. Office of Solid Waste and Emergency Response. January.

Vance, D.B.  1998. "MTBE: Character in Question."  Environmental Technology.
January/February.

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Table 1.  GC Retention Time of MTBE and Associated Degradation Byproducts
Compounds
2- methyl- 1-propene
Acetone
TEA
MTBE
TBF
Retention Time
(minutes)
2.5
3.3
3.9
4.9
6.4
            Table 2. Test Conditions for MTBE Degradation
Chemical Addition
20 mg/L MTBE solution
5% H2O2 solution
Ferrous sulfate solid
H2O2:Fe+2
Test duration
Unit
mL
mL
mg
mole: mole
hr
Test 1
300
1.2
568
1:1
1
Test 2
300
1.2
5.68
100:1
4
Test3
500
2
96
10:1
4
Test 4
500
2
158
6:1
4

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Table 3.  MTBE Degradation Test 1 Results (H2O2:Fe+2= 1:1)
Time
(min)
0

30

60
Aqueous Sample Measurement
pH
4.6

2.49

2.47
MTBE
(mg/L)
21.0
21.2
0.15
0.1
0.1
Acetone
(mg/L)
ND
0.1
3.9
3.7
3.8
TEA
(mg/L)
0.1
0.1
1.0
0.9
0.7
TBF
(mg/L)
0.2
ND
0.8
0.7
0.1
H202
(mg/L)
236

156

125
Total
Fe
(mg/L)
NA

NA

NA
Soluble
Fe(II)
(mg/L)
NA

NA

NA
Gas Sample Measurement
02
0.28

1.89

1.89
CO2
ND

ND

ND
Gas Production
(mL)
NA

ND

ND

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Table 4.  MTBE Degradation Test 2 Results (H2O2:Fe+2 = 100:1)
Time
(min)

0

30

60

150

240

Aqueous Sample Measurement
pH

4.96

3.96

3.98

3.98

4.08

MTBE
(mg/L)

19.6
16.9
22.6
18.2
19.5
21.1
18.0
20.6
19.1
18.2
Acetone
(mg/L)

ND
ND
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.2
TEA
(mg/L)

ND
ND
0.5
0.4
0.5
0.5
0.6
0.7
0.8
0.7
TBF
(mg/L)

ND
ND
1.6
1.3
1.3
1.5
1.2
1.5
1.4
1.3
H202
(mg/L)

236

NA

NA

NA

>200

Total
Fe
(mg/L)
NA

NA

NA

NA

3.2

Soluble
Fe(II)
(mg/L)
NA

NA

NA

NA

ND

Gas Sample Measurement
02
(%)

ND

0.4

NA

0.36

0.52

CO2
(%)

ND

ND

ND

ND

ND

Gas Production
(mL)

NA

ND

ND

ND

ND

                           10

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Table 5.  MTBE Degradation Test 3 Results (H2O2:Fe+2 = 10:1)
Time
(min)

0

5

10

30

60

120

240

Aqueous Sample Measurement
pH

5.41

3.17

3.13

3.1

3.07

3.04

3.01

MTBE
(mg/L)

18.3
16.9
6.6
6.2
6.4
6.2
6.6
6.4
6.2
5.9
5.8
5.7
5.1
5.1
Acetone
(mg/L)

ND
ND
2.3
2.0
2.3
2.1
2.2
2.2
2.2
2.0
2.4
2.3
2.4
2.3
TEA
(mg/L)

ND
ND
4.9
4.4
4.8
4.3
4.6
4.6
4.6
4.3
4.6
4.5
4.5
4.4
TBF
(mg/L)

ND
ND
6.9
5.6
6.9
6.9
6.9
6.4
6.0
5.6
5.2
5.4
5.5
5.6
H202
(mg/L)

236

NA

NA

NA

NA

NA

200

Total
Fe
(mg/L)
NA

NA

NA

NA

NA

NA

3.2

Soluble
Fe(II)
(mg/L)
NA

NA

NA

NA

NA

NA

ND

Gas Sample Measurement
02
(%)

0.87

NA

NA

NA

NA

NA

0.67

CO2
(%)

ND

NA

NA

NA

NA

NA

ND

Gas Production
(mL)

NA

ND

ND

ND

ND

ND

ND

                           11

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Table 6.  MTBE Degradation Test 4 Results (H2O2:Fe+2 = 6:1)
Time
(min)

0
5

10

30

60

120

240

Aqueous Sample Measurement
pH

5.08
2.99

2.96

2.93

2.91

2.88

2.86

MTBE
(mg/L)

17.4
0.7
0.3
0.6
0.4
0.5
0.6
0.5
0.5
0.3
0.3
0.2
0.2
Acetone
(mg/L)

ND
1.8
0.9
1.7
1.1
1.7
1.8
1.8
2.0
1.9
2.1
2.1
2.2
TEA
(mg/L)

0.1
1.5
0.7
1.4
1.1
1.4
1.7
1.3
1.6
1.1
1.3
1.0
1.1
TBF
(mg/L)

ND
3.7
1.7
2.9
2.2
3.0
3.1
2.9
2.7
2.1
2.3
1.8
1.8
H202
(mg/L)

236
NA

NA

NA

NA

NA

185

Total
Fe
(mg/L)
NA
NA

NA

NA

NA

NA

6.8

Soluble
Fe(II)
(mg/L)
NA
NA

NA

NA

NA

NA

0.2

Gas Sample Measurement
02
(%)

ND
NA

NA

NA

NA

NA

1.3

CO2
(%)

ND
NA

NA

NA

NA

NA

ND

Gas Production
(mL)

NA
ND

ND

ND

ND

ND

ND

                           12

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                Table 7. Reactions of Aqueous MTBE with Fenton's Agent Under Several Conditions
                          (All data are after 60 minutes of reaction. All concentrations are in mg/L)
Subject
Molar ratio MTBE: Fe
Molar ratio H2O2 : Fe
Input MTBE (mg/L)
Residual MTBE (mg/L)
Initial pH
Final pH
% MTBE removal
%H2O2* utilized
Acetone (mg/L)
TEA (mg/L)
TBF (mg/L)
Test#l
1:29
1:1
21.10
0.10
4.60
2.47
>99
47
3.80
0.70
0.10
Test #2
1:34.7
100:1
18.25
20.30
4.96
3.98
0
< 15
0.20
0.50
1.40
Test #3
1:34.7
10:1
17.60
6.05
5.41
3.07
66
15
2.10
4.45
5.80
Test #4
1:34.7
6:1
17.40
0.50
5.08
2.91
97
22
0.50
1.45
2.80
* calculated on the basis of input and outputs of hydrogen peroxide
                                                       13

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  Table 8.  Mass Balance of Test #1 (-100% MTBE Removal) and Test #4 (>97% MTBE
                                    Removal)
Input
Output
%
missing
Test #1
21.1 mg/L MTBE=14.36mg/L 'C'
0.1 mg/L MTBE=0.07 mg/L 'C'
3.8mg/L acetone=2.36 mg/L 'C'
0.7 mg/L TEA = 0.46 mg/L 'C'
O.lmg/L TBF = 0.06 mg/L 'C'
Total = 2.95 mg/L 'C'
79.5
Test #4
17.4 mg/L MTBE = 11. 83 mg/L 'C'
0.5 mg/L MTBE = 0. 34mg/L 'C'
1.90 mg/L acetone = 1.18 mg/L 'C'
1.45 mg/L TBA = 0.94 mg/L 'C'
2.80 mg/L TBF = 1.62 mg/L 'C'
Total = 4.08 mg/L 'C'
65.5
Note:  'C' = as carbon.
      In either of these tests, no CO2 or any volatile organic compound was detected.
                                        14

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About the Authors
Dr. Asim B. Ray is a Technical Scientist with the Senior Environmental Employee Program
with U.S. Environmental Protection Agency, National Risk Management Research Laboratory,
Water Supply and Water Resources Division, Urban Watershed Management Branch, 2890
Woodbridge Avenue, Edison, NJ 08837. Dr. Ariamalar Selvakumar is an Environmental
Engineer with the same branch at USEPA.
                                         15

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