AUTONOMOUS, REAL TIME DETECTION OF 58 VOCS IN THE PANAMA CANAL

AUTONOMOUS, REAL TIME DETECTION OF 58 VOCS IN THE PANAMA CANAL

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 A chemical spill occurred in the Elk River in Charleston, WV in 2014 Photo Credit: Tim Kiser 3/16/17 2

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 Photo Credit : David McClenaghan, CSIRO 3/16/17 3

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) Photo Credit : Polimerek 3/16/17 4

Challenges of GC Analysis USEPA Method 8260B 110 compounds via GC-MS Complex chromatogram Can a complex mixture be analyzed by GC? 3/16/17 5

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? 3/16/17 6

Drinking Water at the Panama Canal Man-made, 77 km passageway Connects Atlantic and Pacific Oceans Highly trafficked 3/16/17 7

Drinking Water at the Panama Canal Potential for release of volatile organic compounds (VOCs) Fuel Cargo Liquid chemicals Oil/gas Photo Credit : Stan Shebs 3/16/17 8

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 Photo Credit : Dozenist 3/16/17 9

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 Water Intake at Miraflores Treatment Plant 3/16/17 10

Automatic Testing of VOCs CMS5000 Stationary, wall-mounted instrument Continuous monitoring system that provides detection and quantitation of VOCs (volatile organic compounds) in water Can be integrated into a SCADA system using MODBUS Programmable sample collection system allows for automated, on-site analysis 3/16/17 11

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 3/16/17 12

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) 3/16/17 13

Automatic Testing of VOCs Nickel-63 radioactive source (Ni63) Ionizes the argon gas by emitting beta particles Has a 96 year half life 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 3/16/17 14

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 3/16/17 15

58 Compounds vinyl chloride chloroform trans-1,3- dichloropropene bromoform 4-isopropyltoluene bromomethane 2,2-dichloropropane 1,1,2-trichloroethane styrene 1,3-dichlorobenzene chloroethane 1,2-dichloroethane toluene o-xylene 1,4-dichlorobenzene 1,1-dichloroethene 1,1,1-trichloroethane 1,1-dichloropropene 1,3-dichloropropane trichlorofluoromethane 1,1,2,2- tetrachloroethane 1,2,3-trichloropropane sec-butylbenzene tert-butylbenzene methylene chloride benzene 1,2-dibromoethane isopropylbenzene 1,2-dichlorobenzene dibromochloromethane trans-1,2- dichloroethene 1,1-dichloroethane carbon tetrachloride tetrachloroethene bromobenzene n-butylbenzene dibromomethane 1,1,1,2- tetrachloroethane 2-chlorotoluene 1,2,4- trichlorobenzene MTBE 1,2-dichloropropane chlorobenzene 4-chlorotoluene naphthalene cis-1,2-dichloroethene bromodichloromethan e ethylbenzene n-propylbenzene 1,2,3- trichlorobenzene bromo-chloromethane trichloroethene m-xylene 1,3,5- trimethylbenzene hexachloro-butadiene cis-1,3- dichloropropene p-xylene 1,2,4- trimethylbenzene 3/16/17 16

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. 3/16/17 17

Analysis of VOCs Two GCs with different columns DB-1 (100% PDMS, non-polar) DB-624 (94% PDMS, 4% Cyanopropylphenyl, slightly polar) 3/16/17 18

Analysis of VOCs Each column separates different compounds Water is automatically sampled Attachment to the plumbing system to allow for standard spikes CMS5000 installed at the Panama Canal 3/16/17 19

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 3/16/17 20

Analysis of VOCs 34, 35, 36 DB-1, 1 ppb standard 44, 45 47, 48 5, 6 7 26,27 30 31, 32 33 41 38, 39 43 46 51 52 54 37 1 3 8,9 10 12, 13 16 17 21, 22 42 49 50 53 58 2 4 11 14 15 18 19,20 23 24 25 28 29 40 55 57 56 3/16/17 21

Analysis of VOCs 7,9 5 DB-624, 1 ppb standard 34, 35 2 10, 13 16, 18 14, 17 1 39, 40, 43, 45 46 54 3 8 15 22 26 30 31, 33 32 38 37 41 44 51 47 48 49 52 6 12 11 20 42 50, 53 55 58, 56 4 19 21 23 24, 25 27 28 29 36 57 3/16/17 22

Coelutions Coelution: Two or more chemical compounds elute from a column at the same time, making separation and identification difficult With MS coeluting compounds can be separated using ion profiles In GC analysis coeluting compounds cannot be separately quantified 3/16/17 23

Coelutions on DB-1 vinyl chloride bromomethane chloroform 2,2-dichloropropane trans-1,3- dichloropropene 1,1,2- trichloroethane bromoform styrene chloroethane 1,2-dichloroethane toluene o-xylene trichlorofluoromethane 1,1,1- trichloroethane 1,1-dichloroethene 1,1-dichloropropene 1,3-dichloropropane 1,1,2,2- tetrachloroethane dibromochloromethane 1,2,3- trichloropropane methylene chloride benzene 1,2-dibromoethane isopropylbenzene trans-1,2- dichloroethene carbon tetrachloride 4-isopropyltoluene 1,3- dichlorobenzene 1,4- dichlorobenzene sec-butylbenzene tert-butylbenzene 1,2- dichlorobenzene tetrachloroethene bromobenzene n-butylbenzene 1,1,1,2-1,2,4-1,1-dichloroethane dibromomethane 2-chlorotoluene tetrachloroethane trichlorobenzene MTBE 1,2-dichloropropane chlorobenzene 4-chlorotoluene naphthalene cis-1,2- dichloroethene bromodichlorometh ane trichloroethene hexachlorobutadiene cis-1,3- dichloropropene ethylbenzene m-xylene p-xylene n-propylbenzene bromochloromethane 1,3,5- trimethylbenzene 1,2,4- trimethylbenzene 1,2,3- trichlorobenzene 3/16/17 24

Coelutions on DB-624 vinyl chloride bromomethane chloroform 2,2-dichloropropane trans-1,3- dichloropropene 1,1,2- trichloroethane bromoform styrene chloroethane 1,2-dichloroethane toluene o-xylene trichlorofluoromethane 1,1,1- trichloroethane 1,1-dichloroethene 1,1-dichloropropene 1,3-dichloropropane 1,1,2,2- tetrachloroethane dibromochloromethane 1,2,3- trichloropropane methylene chloride benzene 1,2-dibromoethane isopropylbenzene trans-1,2- dichloroethene carbon tetrachloride 4-isopropyltoluene 1,3- dichlorobenzene 1,4- dichlorobenzene sec-butylbenzene tert-butylbenzene 1,2- dichlorobenzene tetrachloroethene bromobenzene n-butylbenzene 1,1,1,2-1,2,4-1,1-dichloroethane dibromomethane 2-chlorotoluene tetrachloroethane trichlorobenzene MTBE 1,2-dichloropropane chlorobenzene 4-chlorotoluene naphthalene cis-1,2- dichloroethene bromodichlorometh ane trichloroethene hexachlorobutadiene cis-1,3- dichloropropene ethylbenzene m-xylene p-xylene n-propylbenzene bromochloromethane 1,3,5- trimethylbenzene 1,2,4- trimethylbenzene 1,2,3- trichlorobenzene 3/16/17 25

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 3/16/17 26

Analysis of VOCs Calculate the concentration manually by subtraction Example: MTBE 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 3/16/17 27

Analysis of VOCs System alarms when concentrations over 2 ppb are detected 3/16/17 28

Conclusions Two GC systems with purge and trap working in tandem Long term, automated detection of VOCs in water of the Panama Canal Ensure the water in the Panama Canal can be used for both transport and drinking water Photo Credit : Stan Shebs 3/16/17 29