Odour Control at Organics Processing Centre (OPC)
Odour control for the 28,000 ft2 (2601 m2) building consists of a carbon filter that is sized to process 62,500 ft3 air/min (106,188 m3 air/hour) through a stack that is 36” in diameter. The scrubber system contains 21,146 kg of Sulfursorb-A media for odour control and air treatment. The activated carbon filter is sized to provide 1.5 years of air treatment, although the lifespan of the filter will vary depending upon the nature of the feedstocks being received at the facility.
All entry ways to the facility are equipped with fast acting doors and air curtains. Doors are closed prior to material being off-loaded from the trucks and all doors remain closed except for when a truck is entering or leaving the building. All of the air in the building is continuously drawn from the building and cycled through an odour control to ensure that all air within the building is treated through the odour control unit prior to recirculation into the building or discharge to the environment.
The odour control system is designed with continuous emissions monitoring (CEM) technology to monitor hydrogen sulphide concentration. The scrubber is designed to provide continuous air treatment even during media change out. The scrubber is subdivided length-wise so that each side can work independently from one another. During carbon change out, one side is shut down for media change-out while the other side remains in operation with a lower flow. Once change-out has occurred, air flow would be switched to the other side. Spent media is removed and landfilled appropriately. In addition to the use of the CEM hydrogen sulphide sensors, sniff tests and a daily site walk around are part of ensuring adequate odour control on-site.
All entry ways to the facility are equipped with fast acting doors and air curtains. Doors are closed prior to material being off-loaded from the trucks and all doors remain closed except for when a truck is entering or leaving the building. All of the air in the building is continuously drawn from the building and cycled through an odour control to ensure that all air within the building is treated through the odour control unit prior to recirculation into the building or discharge to the environment.
The odour control system is designed with continuous emissions monitoring (CEM) technology to monitor hydrogen sulphide concentration. The scrubber is designed to provide continuous air treatment even during media change out. The scrubber is subdivided length-wise so that each side can work independently from one another. During carbon change out, one side is shut down for media change-out while the other side remains in operation with a lower flow. Once change-out has occurred, air flow would be switched to the other side. Spent media is removed and landfilled appropriately. In addition to the use of the CEM hydrogen sulphide sensors, sniff tests and a daily site walk around are part of ensuring adequate odour control on-site.
ODOUR EMISSIONS SUMMARY AND INTERPRETATION OF RESULTS
Odour emissions from the odour control stacks and the biogas upgrader are based on stack characteristics and an odour emission of 1,000 ou as a worst case scenario. The AERMOD model provides predicted ambient concentrations at each human receptor in one-hour averages. The conversion factor provided in the Regulation of 1.65 is used to convert from 1-hour to 10-minute averages.
The emission concentrations are compared to the MECP odour threshold of less than 1 ou at human receptors. The MECP Dispersion Modelling Guidelines allow for the removal of the anomalous eight hours with the highest 1-hour average predicted concentrations in each single meteorological year. The summary of all the data points that is provided in Table 2 below indicate that there are no data points above the 1 ou threshold (prior to removal of meteorological anomalies).
Table 2 below provides a summary of all of the data for five years of meteorological data at the site. In the table below you will see the number of data points (1-hour of time per data point) where data odour concentrations were within each range. This table indicates that over 96% of the resulting odour units are below 0.1 ou at all four human receptors.
Odour emissions from the odour control stacks and the biogas upgrader are based on stack characteristics and an odour emission of 1,000 ou as a worst case scenario. The AERMOD model provides predicted ambient concentrations at each human receptor in one-hour averages. The conversion factor provided in the Regulation of 1.65 is used to convert from 1-hour to 10-minute averages.
The emission concentrations are compared to the MECP odour threshold of less than 1 ou at human receptors. The MECP Dispersion Modelling Guidelines allow for the removal of the anomalous eight hours with the highest 1-hour average predicted concentrations in each single meteorological year. The summary of all the data points that is provided in Table 2 below indicate that there are no data points above the 1 ou threshold (prior to removal of meteorological anomalies).
Table 2 below provides a summary of all of the data for five years of meteorological data at the site. In the table below you will see the number of data points (1-hour of time per data point) where data odour concentrations were within each range. This table indicates that over 96% of the resulting odour units are below 0.1 ou at all four human receptors.
CONCLUSIONS
The AERMOD dispersion model of odour emissions from the proposed facility indicate that the facility will not result in negative odours at the human receptors.
It must be reiterated that the use of 1,000 ou exiting each odour control stack is a very conservative value and it is anticipated that the outlet from the stacks will be much lower Regardless of this conservatism, the results from the dispersion model indicate that the MECP requirement of less than 1 ou at all human receptors is met using a dispersion model with site-specific meteorological data.
The AERMOD dispersion model of odour emissions from the proposed facility indicate that the facility will not result in negative odours at the human receptors.
It must be reiterated that the use of 1,000 ou exiting each odour control stack is a very conservative value and it is anticipated that the outlet from the stacks will be much lower Regardless of this conservatism, the results from the dispersion model indicate that the MECP requirement of less than 1 ou at all human receptors is met using a dispersion model with site-specific meteorological data.
