AQ_F_0800112_20220722_MOD_ModRvw

DIVISION OF AIR QUALITY
July 22, 2022
MEMORANDUM
TO: Robert Bright, Permit Engineer, WaRO
Yongcheng C en, Permit Coordinator, WaRO
FROM: Nancy Jones eteorologist, Air Quality Analysis Branch(AQAB)
4-
THROUGH: Tom Anderson, AQAB Supervisor
SUBJECT: Review of Toxics Dispersion Modeling Analysis GreenGasUSA
Lewiston, Bertie County, North Carolina Facility ID: 0800112
I have reviewed the dispersion modeling analysis, received June 10, 2022 for GreenGasUSA
(GreenGas) in Lewiston, Bertie County, North Carolina. The modeling was submitted with the
permit application to construct and operate a renewable gas facility at the Perdue Farms
processing plant. The purpose for modeling was to demonstrate compliance with guidelines
specified in 15A NCAC 2D .1104 for Toxic Air Pollutants (TAPs)emitted in excess of the Toxic
Permitting Emission Rates(TPERs)listed in 15A NCAC 2Q .0711. The modeling adequately
demonstrates compliance for hydrogen sulfide on a source-by-source basis.
Hydrogen sulfide, was evaluated using AERMOD(v2l 112) using the 2014-2018 surface data for
Elizabeth City and upper air data for Newport. Direction-specific building dimensions,
determined using EPA's BPIP-Prime program (04274), were used as input to the model for
building wake effect determination. Receptors were placed at 25 meter intervals along the
fenceline and in nested grids out to 2,000 meters. The facility has multiple flares that emit
hydrogen sulfide. To maximize operational flexibility, a worst-case stack approach was used
and modeled impacts were scaled up to develop a facility-wide limit of 112.21 lbs/day. Release
parameters and emission rates are attached.
Maximum Impacts —Optimized Emissions
GreenGas Lewiston,Bertie County,North Carolina
Averaging Max. Conc. AAL % of
Pollutant Period (µg/m) (µg/m3) AAL
Hydrogen Sulfide 24-hour 118.8 120 99
This compliance demonstration assumes the source parameters and pollutant emission rates used
in the dispersion modeling analysis are correct.
cc: Tom Anderson
Nancy Jones

Model Inputs GreenGas Lewiston,Bertie County,NC
Easting Northing Base Stack Exit Stack
Source ID (X (I) Elevation Height Temp. Velocity Diameter 1-12S
m m (m) (ft) (°F (fps) ft lb/hr
FLRIAC 300033 4001999 27 34 1832 66 2.76 7.94
FLRIBC 300051 4002002 26 34 1832 66 2.76 7.94
FLRIAC 300403 4001812 26 26 1832 66 1.08 7.94
FLR2BC 300424 4001815 26 26 1832 66 1.08 7.94
FLR2ANC 300403 4001812 26 21 169 50 0.49 7.94
FLR2BNC 300424 4001815 26 21 169 50 0.49 7.94