Appendix A of the ESDM used…

Appendix A of the ESDM used AERMOD calculations for emission sources from the many stacks. For three of these emission the calculations are predicted on rural settings. the Coronation Drive site is urban, not rural, with residential areas in the immediate vicinity. concern that, especially for emergency releases, these data based on a rural setting will not be safe for residents.

Emission Source and 4: “STACKP4a and STACKP4b” Natural Gas Boiler for Anaerobic Digesters
As per Procedure for Preparing an Emission Summary and Dispersion Modelling Report
[Guideline A-10], Section 7.1.1 Combustion of Natural Gas and Propane, there is one significant
contaminant associated with Emission Source 4: nitrous oxides (NOx).

AERMOD INPUT Input
Type of Emission Point Source
Setting Rural
Stack height [m] 6.3 (2.6 m tall building + 3.7 m tall stack)
Stack Diameter [m] 0.3556
Temperature [K] 394
Exhaust Velocity [m/s] 2.2The

Emission Source 5: “STACKP5” Biogas Upgrader
There are three contaminants associated with P5: total reduced sulfur (TRS), methane (CH4)
and carbon dioxide (CO2).
The expected TRS emission from the biogas upgrader is 1 ppm H2S, but a conservative value

AERMOD INPUT Input
Type of Emission Point Source
Setting Rural
Stack height [m] 5.5
Stack Diameter [m] 0.1AERMOD INPUT Input
Type of Emission Point Source

Emission Source 6: “STACKP6” Emergency Flare
There is one open flare on-site that is capable of flaring all of the biogas produced in the
anaerobic digester in case the upgrader is not functional (maintenance). In this case, biogas
that is flared will not be treated through the desulphurization process used to pre-treat biogas
prior to the biogas upgrader.
There are five contaminants that are being modelled from the flare and they are nitrous oxides
(NOx), particulate matter (PM), carbon dioxide (CO2), sulphur dioxide (SO2) and methane (CH4).
Sulphur dioxide is considered at 500 ppmH2S.
The flare that is chosen has an 12” diameter outlet which corresponds to a capacity of 4095 m3
biogas/hour. The expected biogas production at the facility is 2,800 m3 biogas/hour and as such
the flare is modelled with this flowrate and a 10% contingency for overgas production. This is a
flowrate of 3,080 m3 biogas/hour.

Emission Source 7: “STACKP7a and STACKP7b” Pressure Relief Valve (PRV) at AD
In the event that biogas upgrader and flare cannot consume all of the biogas that is generated,
the emergency pressure relief valve may be engaged to quickly reduce pressure within the AD.
There is one contaminant from the pressure relief valve: hydrogen sulphide as total reduced
sulfur (TRS). Hydrogen sulphide is considered at operating condition of 500 ppm H2S.

AERMOD INPUT Input
Type of Emission Point Source
Setting Rural
Stack height [m] 3
Stack Diameter [m] 0.2032
Temperature [K] 313
Exhaust Velocity [m/s] 8
The emission rates for both cases of TRS are calculated as follows.
1. Total Reduced Suflur, 500 ppm H2S
The hydrogen sulphide (H2S) from the PRV is 1,000 ppmH2S, which is