perimeter air monitoring for vocs and pm at mgp sites- exceedances – frequency, origins/causes and...
DESCRIPTION
TRC's Gary Hunt describes issues related to effective air monitoring during remediation at manufactured gas plant (MGP) and other industrial sites. This presentation was part of the Fifth International Symposium & Exhibition on the Redevelopment of Manufactured Gas Plant Sites (MGP 2014).TRANSCRIPT
Gary Hunt, Principal Scientist and Vice President TRC Environmental Corporation
650 Suffolk Street Lowell, MA 01854
Perimeter Air Monitoring For VOCs and PM at MGP Sites –
Exceedances – Frequency, Origins/Causes and Mitigation
1
Ø TVOC/PM alarm levels and their origins
Ø TVOC/PM exceedances and causes
Ø Data capture – network performance
Ø Data validation criteria
Ø Exceedances – corrective actions and mitigation
Ø PM10 as a surrogate for naphthalene isomers
2
Ø PM as PM10
Ø NAAQS of 150 µg/m3 (24 hour TWA)
Ø Short averaging times (5, 10 minute average)
Ø With and without background correction (most predominant upwind station)
3
Ø 0.5 ppm as Benzene (New Jersey)
Ø 1.4 ppm as Benzene (Michigan)
Ø Based upon published human inhalation exposure data for Benzene
Ø ATSDR Acute Minimum Risk Level of 29 µg/m3 (14-days) for example
Ø Short averaging times typical (5, 10, 15 minute average)
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5
MGP Site
No. Stations
TVOC Interval
(minutes)No.
MeasurementsNo.
Exceedances% of Total
A 3 15 9,625 3 0.03
B 4 15 NA 2 NA
C 4 5 46,000 31 0.07
D 4/5 10 101,000 3 0.003
156,625 37 0.02*TVOC Action Level = 0.5 ppm (500 ppb v/v)
TOTAL (ALL)
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ªTVOC >0.5ppm as measured by ppb RAE PID. Measured as Benzene
#MGP Site Exceedance Cause
3 A Refueling gasoline powered chainsaw1 B PVC pipe assembly (dope cement)1 B Spray paint cans discharge -‐ roll off disposal1 C Cutting pavement -‐ mini saw exhaust1 C Gas holder excavation2 C Tar holder excavation1 C Gas holder excavation3 C Cutting metal/tubing power saw exhaust2 C Excavation and load out -‐ MGP soil2 D Fuel tank cutting-‐foam fill caused fuel discharge1 D Relocation of same fuel tank (wrapped in plastic)
7
PM10* Exceedance History Summary of Results-Four (4) MGP Sites
MGP Site
No. Stations
PM10
Interval (minutes)
No. Measurements
No. Exceedances
% of Total
A 3 5 28,900 18 0.062
B 4 5 NA 89 NA
C 4 10 23,000 255 1.1
D 4/5 10 15,000 39 0.26
66,900 401 0.60
*PM10 Action Level = 150 µg/m3
@ Phase 2 results only
TOTAL
@
8
PM10 Exceedances* Typical Causes/Origins
*PM10 > 150 µg/m3 Action/Alarm Level
# MGP Site Cause
18 3 7 2 15 2 2 2 5 3 5 5
A B B B B B B C C C C C
Asphalt cu:ng – on street off site Excavator loading trucks exhaust Diesel truck exhaust – parked idling Pavement cu:ng/saw on street – off site Adding/mixing of calciment with wet excavated material Stockpiling of excavated material Clean backfill delivery ExcavaNon of contaminated material Leveling of sand & soil; excavaNon stopped to allow for miNgaNon ExcavaNon of holder ExcavaNon of holder – work stoppage for intensive wet down Backfilling of excavaNon area
Remedial Activity Corrective Action
#Exceedances
3 Asphalt Sweeping
TOTAL: 50
Stockpiled Soils and Fugitive Dust 1
Excavation Activities 1
Site Grading 6
Truck and Vehicle Traffic and Fugitive Dust 6
28 Post Remediation Site Paving
Site Activity
4 Asphalt Cutting
1 Vehicle Exhaust (idling)
Figure 4 PM10 Exceedance Types - % Distribution
(> 150 ug/m3 for 5 minute average)
Excavation Activities2% Stockpiled Soils and
Fugitive Dust2%
Site Grading12%
Post Remediation Site Paving
56%
Truck and Vehicle Traffic and
Fugitive Dust12%
Asphalt Sweeping6%
Asphalt Cutting8%
Vehicle Exhaust (idling)
2%
Post Remediation Site Paving
Asphalt Cutting
Asphalt Sweeping
Vehicle Exhaust (idling)
Truck and Vehicle Traffic and Fugitive DustSite Grading
Excavation Activities
Stockpiled Soils and FugitiveDust
Note: 197,500 PM10 5 minute averages collected during 192 day program.
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Ø Goal of > 90% on a Weekly Basis
Ø Network Wide – All Stations
Ø TVOC/PM10 Combined
Ø Defined as ratio of number of valid measurements collected weekly to total number of time intervals when monitoring is required*
*Monitoring during active remediation only; (8-10 hours/day ) 24 hours/day, etc.
10
Ø Instrument Malfunction – PID NOT Measuring (e.g., Pump, Detector)
Ø Data Logger Fault
Ø Calibration Event
Ø Weather Bias (e.g., high humidity, driving rain, etc.)
Ø Instrument Repair/Maintenance and/or Replacement (Downtime due to “swap out”).
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Ø Parts and spare instruments on site. Ø Multiple calibrations daily. Ø Power source/supply redundancy (marine
battery). Ø Raw data logged/archived at each station. Ø Raw data logged on central computer. Ø Background corrected data reported and stored
on hard drive.
12
Data capture (weekly %) = valid data points (TVOC + PM10)
3600ª x100 ª3600 = #10 minute periods in a calendar week (60/10 hr day x 5 days/week x 2 (TVOC + PM10 ) x 6 stations).
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90% Goal
Mean = 96.4%
Week #
15
} On Site Enclosure- “Sprung Building” } Water/Foam Spray } Perimeter Monitoring with Corrective Actions
Triggered via Action Levels } Cover Soil Piles (Tarps) } Public Outreach- Odor Hotline } Document Off Site Emissions < Levels of
Health Concern
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05
101520253035404550
NaphthalenePM10
Date 5/10 6/7 6/21 7/5 7/19 8/2 8/16 9/13 10/11 12/13
Temp. F°
54.0 63.8 76.4 79.6 63.6 79.7 77.7 72.6 58.7 26.3
ug/m
3
18
05
101520253035404550
NaphthalenePM10
Date 5/10 6/7 6/21 7/5 7/19 8/2 8/16 9/13 10/11 12/13
Temp. F°
54.0 63.8 76.4 79.6 63.6 79.7 77.7 72.6 58.7 26.3
ug/m
3
19
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Thank You For Your Attention !
Gary Hunt TRC Corporation 650 Suffolk Street Lowell, MA 01854 978.656.3551 (w) 508.320.5479 (c)
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