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→Performance Test Results
In general, OGS should not be installed as stand-alone units for [[water quality]] treatment. While every effort has been made to ensure that the ISO 14034 verified lab test is an accurate representation of actual performance, there remains uncertainty about how lab results translate to the field, particularly for group 2 technologies. Installing OGS only as [[pretreatment]] to other downstream practices helps to mitigate this uncertainty and risk because downstream stormwater treatment practices can be relied on to provide a second line of defense.
In general, OGS should not be installed as stand-alone units for [[water quality]] treatment. While every effort has been made to ensure that the ISO 14034 verified lab test is an accurate representation of actual performance, there remains uncertainty about how lab results translate to the field, particularly for group 2 technologies. Installing OGS only as [[pretreatment]] to other downstream practices helps to mitigate this uncertainty and risk because downstream stormwater treatment practices can be relied on to provide a second line of defense.
A summary of OGS MTD test results from the verification statements is provided [https://etvcanada.ca/home/verify-your-technology/current-verified-technologies/ here]<br>
A summary of OGS MTD test results from the verification statements is provided [https://etvcanada.ca/home/verify-your-technology/current-verified-technologies/ here]<br>
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Sediment removal performance results were relatively consistent across different MTD designs, with slightly more variation at higher surface loading rates (see Graph below). <br>
Sediment removal efficiencies for ISO 14034 verified OGS. '''Group 1''' units (n=10) are conventional OGS with large openings. '''Group 2''' units (n=2) contain additional components that filter or strain flows. Sediment removal performance results were relatively consistent across different MTD designs, with slightly more variation at higher surface loading rates (see Graph below). <br>
[[File:OGS-Protocol-Webpage-Image.jpg|thumb|320px|Performance testing of an OGS unit in St Anthony Falls Laboratory in Minnesota (Saddoris, et al. 2010)<ref>Saddoris, D.A., McIntire, K.D., Mohseni, O., and J.S. Gulliver, 2010. Hydrodynamic Separator Sediment Retention Testing – Final Report. Minnesota Department of Transportation, St. Paul, MN.</ref>]]
'''<small>*Note:''' Oil Grit Separators do not achieve the 80% removal efficiency required for stand alone application in Ontario, even at very low flow rates.</small>
'''<small>*Note:''' Oil Grit Separators do not achieve the 80% removal efficiency required for stand alone application in Ontario, even at very low flow rates.</small>
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[[File:OGS-Protocol-Webpage-Image.jpg|thumb|320px|Performance testing of an OGS unit in St Anthony Falls Laboratory in Minnesota (Saddoris, et al. 2010)<ref>Saddoris, D.A., McIntire, K.D., Mohseni, O., and J.S. Gulliver, 2010. Hydrodynamic Separator Sediment Retention Testing – Final Report. Minnesota Department of Transportation, St. Paul, MN.</ref>]]
[[File:Surface loading groups 1 & 2 OGS Update.png|900px]]<br>
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The graph above shows the average, minimum and maximum sediment removal efficiencies for ISO 14034 verified OGS at seven surface loading rates (n = 10).
The graph above shows the average, minimum and maximum sediment removal efficiencies for ISO 14034 verified OGS at seven surface loading rates (n = 10).