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Challenges of Water Monitoring
• Volatile Organic Compounds
(VOCs) can have negative
health impacts even at ppb
levels
• VOC concentrations can
fluctuate widely depending on
water system conditions
• Public water utilities are
concerned about sudden
spikes in VOC concentrations
caused by unexpected events
8/16/2017Autonomous, Real Time Detection of 58 VOCs in the Panama Canal 2
Site of chemical spill into the Elk River in
Charleston, WV
http://news.nationalgeographic.com/news
Challenges of Water Monitoring
• How is water monitoring
accomplished?
• Manual collection of grab samples
• Problems
• Time consuming
• Difficult to collect enough samples
evaluate time trends
• Transport of samples: sample integrity
may be compromised
• Cost of third-party sample analysis
• Solution
• Automatic, integrated sampling
system
8/16/2017Autonomous, Real Time Detection of 58 VOCs in the Panama Canal 3
http://www.sacwsd.org
Challenges of Water Monitoring
• How are VOCs in
water analyzed?
• Analytes must be
purged out of water
and into the gas phase
• Analysis by gas
chromatography (GC)
or gas chromatography
coupled with mass
spectrometry (GC-MS)
8/16/2017Autonomous, Real Time Detection of 58 VOCs in the Panama Canal 4
Challenges of GC Analysis
• USEPA Method
8260B
• 110 compounds via
GC-MS
• Complex
chromatogram
• Can a complex
mixture be analyzed
by GC?
8/16/2017Autonomous, Real Time Detection of 58 VOCs in the Panama Canal 5
http://www.restek.com/chromatogram/view/GC_EV00640
Challenges of GC Analysis
• Data Overload
• How can treatment plant operators receive the maximum impact from continuous data?
• Can GC analysis of VOCs be automated?
8/16/2017Autonomous, Real Time Detection of 58 VOCs in the Panama Canal 6
Drinking Water at the Panama Canal
• Man-made, 77 km
passageway
• Connects Atlantic and
Pacific Oceans
• Highly trafficked
8/16/2017 7
http://www.shutterstock.com/
Autonomous, Real Time Detection of 58 VOCs in the Panama Canal
Drinking Water at the Panama Canal
• Potential for release of
volatile organic
compounds (VOCs)
• Fuel
• Cargo
• Liquid chemicals
• Oil/gas
8/16/2017 8
http://maritime-connector.com/wiki/panamax/
Autonomous, Real Time Detection of 58 VOCs in the Panama Canal
Drinking Water at the Panama Canal
• Three water treatment
plants
• >100 million gallons of
water daily
• Miraflores (50 MGD)
and Mendoza (40 MGD)
on the Pacific
• Mount Hope (35MGD) on
the Atlantic
• CMS5000 installed at the
Miraflores Filtration Plant
8/16/2017 9
http://www.thepanamadigest.com
Autonomous, Real Time Detection of 58 VOCs in the Panama Canal
Drinking Water at the Panama Canal
• Miraflores is the largest
treatment plant on the
Panama Canal
• 40% of drinking water for
Panama City is
processed by the
Miraflores Filtration Plant
• Automated testing of
VOCs will help the water
utility to ensure public
safety
8/16/2017 10
Water Intake at Miraflores Treatment Plant
Autonomous, Real Time Detection of 58 VOCs in the Panama Canal
8/16/2017
Automatic Testing of VOCs
• CMS5000
• Autonomous testing
• In-house screening
• Less wasted time and money
Autonomous, Real Time Detection of 58 VOCs in the Panama Canal 11
8/16/2017 12
Automatic Testing of VOCs
• Water samples are continuously pumped through the sampling chamber
• VOCs are extracted from water using purge and trap technology
• Argon gas bubbles through the water sample
• A portion of the VOCs will pass from the water phase to the gas phase and collect in the “headspace” at the top of the sample collection tube
• The sample is collected from the headspace
Autonomous, Real Time Detection of 58 VOCs in the Panama Canal
8/16/2017
Automatic Testing of VOCs
• VOCs are
loaded onto a
Tri-Bed
concentrator
• The sample is
then desorbed
onto the GC
column
• Detection by a
Micro Argon
Ionization
Detector
(MAID)
Autonomous, Real Time Detection of 58 VOCs in the Panama Canal 13
8/16/2017
Automatic Testing of VOCs
• Nickel-63 radioactive source (Ni63)
• Ionizes the argon gas by emitting beta particles
• Detection Capabilities
• VOCs with ionization potentials (IP) < 11.7 eV
• Boiling point up to 250 °C
• PPT detection limit for most compounds
• 0.5 ppb – 1 ppm
Autonomous, Real Time Detection of 58 VOCs in the Panama Canal 14
8/16/2017
Panama Canal
• Requires the automated monitoring of
several USEPA 8260B compounds
• Compounds must be detected to 1 ppb
• SCADA system integration
• Ability to analysis calibration check
standards
• Generation of alarms
Autonomous, Real Time Detection of 58 VOCs in the Panama Canal 15
58 Compounds
8/16/2017 16
vinyl chloride chloroformtrans-1,3-
dichloropropenebromoform 4-isopropyltoluene
bromomethane 2,2-dichloropropane 1,1,2-trichloroethane styrene 1,3-dichlorobenzene
chloroethane 1,2-dichloroethane toluene o-xylene 1,4-dichlorobenzene
trichloro-
fluoromethane1,1,1-trichloroethane 1,3-dichloropropane
1,1,2,2-
tetrachloroethanesec-butylbenzene
1,1-dichloroethene 1,1-dichloropropenedibromo-
chloromethane1,2,3-trichloropropane tert-butylbenzene
methylene chloride benzene 1,2-dibromoethane isopropylbenzene 1,2-dichlorobenzene
trans-1,2-
dichloroethenecarbon tetrachloride tetrachloroethene bromobenzene n-butylbenzene
1,1-dichloroethane dibromomethane1,1,1,2-
tetrachloroethane2-chlorotoluene
1,2,4-
trichlorobenzene
MTBE 1,2-dichloropropane chlorobenzene 4-chlorotoluene naphthalene
cis-1,2-dichloroethenebromodichloromethan
eethylbenzene n-propylbenzene
1,2,3-
trichlorobenzene
bromo-chloromethane trichloroethene m-xylene1,3,5-
trimethylbenzenehexachloro-butadiene
cis-1,3-
dichloropropenep-xylene
1,2,4-
trimethylbenzene
Autonomous, Real Time Detection of 58 VOCs in the Panama Canal
8/16/2017
Panama Canal
Challenge: Develop an analytical method
that will autonomously detect and quantify 58
VOCs by GC
Proposal: Use two GC systems with complementary column phases run in tandem.
Autonomous, Real Time Detection of 58 VOCs in the Panama Canal 17
Analysis of VOCs
8/16/2017 18
• Two GCs with different columns
DB-1 (100% PDMS, non-polar) DB-624 (94% PDMS, 4%
Cyanopropylphenyl, slightly polar)
Autonomous, Real Time Detection of 58 VOCs in the Panama Canal
Analysis of VOCs
8/16/2017 19
• Each column separates
different compounds
• Water is automatically sampled
• Attachment to the plumbing
system to allow for standard
spikes
Autonomous, Real Time Detection of 58 VOCs in the Panama Canal
CMS5000 installed at the Panama Canal
GC Method
• Calibration 1-10 ppb
• 51 minute method
• 15 minute isothermal hold time at 45 °C, followed by slow ramp
• Separation of early eluting compounds
• Calibration stable over 4-6 months
8/16/2017 20Autonomous, Real Time Detection of 58 VOCs in the Panama Canal
1
2
4
5, 6
7
8,9 10
11
14
15
1617
18
19,20
21, 22
24
25
26,27
28 29
30
31, 32
33
34, 35, 36
37
38, 39
40
41
23
43
44, 45
46
47, 48
49
50
5152
53
54
55
56
57
58
423
12, 13
Analysis of VOCs
DB-1, 1 ppb standard
8/16/2017Autonomous, Real Time Detection of 58 VOCs in the Panama Canal 21
1
3
4
5
6
10,
13
1112
15
16, 18
14,
17
22
20
1921
23
26
24, 25
30
27
2829
32
31,
33
34, 35
38 37
36
41
39, 40, 43,
45
44
46
48
47
51
49
52
50, 53
54
55
58,
56
57
42
2
7,9
8
Analysis of VOCs
DB-624, 1 ppb standard
8/16/2017Autonomous, Real Time Detection of 58 VOCs in the Panama Canal 22
Coelutions
• Coelution: Two or more chemical compounds elute from a column at
the same time, making separation and identification difficult
8/16/2017 23
• With MS coeluting compounds
can be separated using ion
profiles
• In GC analysis coeluting
compounds cannot be
separately quantified
Autonomous, Real Time Detection of 58 VOCs in the Panama Canal
Coelutions on DB-1
8/16/2017 24
vinyl chloride chloroformtrans-1,3-
dichloropropenebromoform 4-isopropyltoluene
bromomethane2,2-
dichloropropane
1,1,2-
trichloroethanestyrene
1,3-
dichlorobenzene
chloroethane 1,2-dichloroethane toluene o-xylene1,4-
dichlorobenzene
trichloro-
fluoromethane
1,1,1-
trichloroethane
1,3-
dichloropropane
1,1,2,2-
tetrachloroethanesec-butylbenzene
1,1-dichloroethene1,1-
dichloropropene
dibromo-
chloromethane
1,2,3-
trichloropropanetert-butylbenzene
methylene chloride benzene 1,2-dibromoethane isopropylbenzene1,2-
dichlorobenzene
trans-1,2-
dichloroethene
carbon
tetrachloridetetrachloroethene bromobenzene n-butylbenzene
1,1-dichloroethane dibromomethane1,1,1,2-
tetrachloroethane2-chlorotoluene
1,2,4-
trichlorobenzene
MTBE1,2-
dichloropropanechlorobenzene 4-chlorotoluene naphthalene
cis-1,2-
dichloroethene
bromodichlorometh
aneethylbenzene n-propylbenzene
1,2,3-
trichlorobenzene
bromo-
chloromethanetrichloroethene m-xylene
1,3,5-
trimethylbenzene
hexachloro-
butadiene
cis-1,3-
dichloropropenep-xylene
1,2,4-
trimethylbenzene
Coelutions on DB-624
8/16/2017 25
vinyl chloride chloroformtrans-1,3-
dichloropropenebromoform 4-isopropyltoluene
bromomethane2,2-
dichloropropane
1,1,2-
trichloroethanestyrene
1,3-
dichlorobenzene
chloroethane 1,2-dichloroethane toluene o-xylene1,4-
dichlorobenzene
trichloro-
fluoromethane
1,1,1-
trichloroethane
1,3-
dichloropropane
1,1,2,2-
tetrachloroethanesec-butylbenzene
1,1-dichloroethene1,1-
dichloropropene
dibromo-
chloromethane
1,2,3-
trichloropropanetert-butylbenzene
methylene chloride benzene 1,2-dibromoethane isopropylbenzene1,2-
dichlorobenzene
trans-1,2-
dichloroethene
carbon
tetrachloridetetrachloroethene bromobenzene n-butylbenzene
1,1-dichloroethane dibromomethane1,1,1,2-
tetrachloroethane2-chlorotoluene
1,2,4-
trichlorobenzene
MTBE1,2-
dichloropropanechlorobenzene 4-chlorotoluene naphthalene
cis-1,2-
dichloroethene
bromodichlorometh
aneethylbenzene n-propylbenzene
1,2,3-
trichlorobenzene
bromo-
chloromethanetrichloroethene m-xylene
1,3,5-
trimethylbenzene
hexachloro-
butadiene
cis-1,3-
dichloropropenep-xylene
1,2,4-
trimethylbenzene
Analysis of VOCs
• If a compound coelutes on one column but not the other, it can be
quantified
• If a compound coelutes on both columns it cannot be quantified by
the software
• Five compounds coelute on both columns
• MTBE
• 2,2-dichloropropane
• n-propylbenzene
• 1,1,1,2-tetrachloroethane
• 1,1,2,2-tetrachloroethane
8/16/2017 26Autonomous, Real Time Detection of 58 VOCs in the Panama Canal
Analysis of VOCs
• Calculate the concentration manually by subtraction
• Example: MTBE
8/16/2017 27
Conc. 1,1-DCE/MTBE, Column 1 – Conc. 1,1-DCE, Column 2 =
Conc. MTBE
Conc. trans-1,2-DCE/MTBE, Column 2 –
Conc. trans-1,2-DCE, Column 1 = Conc. MTBE
Autonomous, Real Time Detection of 58 VOCs in the Panama Canal
Analysis of VOCs
• System alarms when concentrations over 2 ppb are detected
8/16/2017 28Autonomous, Real Time Detection of 58 VOCs in the Panama Canal
Conclusions
• Two GC systems with purge and trap working in tandem
• Long term, automated detection of VOCs in water of the Panama
Canal
8/16/2017 29
https://priceonomics.com
• Ensure the water
in the Panama
Canal can be
used for both
transport and
drinking water
Autonomous, Real Time Detection of 58 VOCs in the Panama Canal