Draft Air Quality & Odour Net Effects Analysis & Comparative Evaluation Report

Transcription

1 Clean Harbors Canada Inc. Lambton Landfill Expansion Environmental Assessment Draft Air Quality & Odour Net Effects Analysis & Prepared By: JANUARY, 2014

2 Executive Summary Two expansion alternatives were identified in the approved Terms of Reference (ToR) and developed to a preliminary conceptual design level. Alternative 1 Vertical Expansion On-Site would involve the vertical expansion of the existing landfill site (i.e., expansion would take place over the previously approved and landfilled areas of the site) (see Figure 1). Alternative 2 Shallow Entombment Off-Site would involve the expansion of the site to the south of the existing landfill on adjacent lands already owned by Clean Harbors (see Figure 2). Conceptual designs for these two Alternatives have been further refined in the Conceptual Design Report (CDR), which was made available during the EA to St. Clair Township and the appropriate review agencies, First Nations, Métis organizations, and the public for their review and comment. This report utilizes the findings of the Air Quality & Odour Existing Conditions Report, the Emission Summary and Dispersion Modelling (ESDM) Reports, conditions associated with the currently approved landfill at closure, and the CDR to conduct net effects analyses for the two alternatives proposed for the Clean Harbors Lambton Landfill Expansion, in accordance with the methodology outlined in the approved ToR. This report also details the comparative evaluation of the two proposed Alternatives with respect to Air Quality & Odour based on the results of the net effects analyses. As part of the effects assessment, an ESDM Report was prepared for each alternative to predict the potential maximum point-of-impingement (POI) concentrations based on the operating conditions where all Facility air emission sources would be operating simultaneously at their individual maximum rates of production. The Facility was assessed from the ground up to determine all potential sources of air emissions. These sources are documented in detail in the ESDM Reports, and include the Thermal Desorption Unit (TDU) and support processes, Facility laboratory exhausts, the incinerator stack and pre-treatment system tanks, the land disposal restrictions (LDR) baghouse and fugitive emission sources. The Facility emission sources and locations are shown on Figure 3 and Figure 4 for Alternative 1 and Alternative 2, respectively. Each source was assessed individually to determine potential air contaminant emissions and in each case an appropriate estimation methodology was selected. Methods used include stack testing, mass balance calculations, engineering calculations and published emission factors. Potential compounds emitted from the Facility include volatile organic compounds (VOCs), products of combustion, particulate matter, metals and polychlorinated biphenyls (PCBs). A complete listing of all compounds is provided in the ESDM Reports. The potential maximum emission rates for each contaminant emitted from the Facility sources were calculated in accordance with the Ministry of the Environment s publication "Summary of Standards and Guidelines to Support Ontario Regulation 419/05 Air Pollution Local Air Quality" dated April The results of the net effects analyses for Air Quality & Odour for both Alternatives are detailed in the ESDM Reports in Appendix B and C. The ESDM Reports represent the potential maximum worstcase off-site POI concentrations for each Alternative based on the maximum equipment operating capacity and the worst-case on-site truck routes. For the purposes of air quality and odour assessments, point-of-impingement impacts at the property line or beyond are assessed. In addition, potential air emissions from the short-term construction activities, such as fugitive dust, for each Alternative are discussed in Section 2.2. It should be emphasized that Clean Harbors has a Fugitive Dust and Odour Best Management Plan in place to manage and mitigate fugitive dust emissions from the site and this plan will continue regardless of the Alternative chosen. The management plan will effectively manage and mitigate potential emissions of particulate, and therefore these emissions were not assessed quantitatively. 09ra_ _Net Effects Analysis_Air Quality_ Docx i

3 The worst-case net effects are also representative of the potential net effects for an extended site life at an average waste receipt rate of 130,000 tonnes per year. Air emissions from the Facility result in predicted POI concentrations that are below the O. Reg. 419/05 criteria. The AERMOD air dispersion model, used in the ESDM Reports, calculates the predicted maximum off-site POI concentration for each contaminant. The model uses a grid that considers the Facility property boundary and any receptor within five kilometres of the property boundary. An additional receptor grid was used at the Aamjiwnaang First Nation lands to identify the predicted maximum offsite POI concentration for each contaminant at any potential receptors within the Aamjiwnaang First Nation boundary. Further details on the receptor grids used in the AERMOD air dispersion modelling are provided in the ESDM Reports. For normal, long term Facility operation, Alternative 1 has slightly higher potential off-site POI concentrations than Alternative 2; however, the difference is not considered substantial. In order to better understand which Alternative is preferred, potential short-term off-site impacts from construction activities were considered. Potential off-site POI impacts from construction activities would be higher for Alternative 2 as a greater degree of construction is required; earth-moving construction activities and wind erosion of stockpiles are related to potential emissions of particulate. Section 2.2 provides further detail on the construction activities and the discussion for each Alternative. Due to the nested grid method that the AERMOD model uses, the number of off-site receptors evaluated for air quality and odour considerations for each Alternative is the same. For Alternative 2, the potential net increase in POI concentrations at the southern receptors is higher than the potential net increase in POI concentrations at the northern receptors, as they are already exposed to air contaminant emissions from the existing landfill, whereas the southern receptors are not located in close proximity to the existing landfill. Therefore, Alternative 1 is preferable when considering the number of off-site receptors potentially affected during long term normal operation of the Facility. Under normal operations, there are currently no off-site odour concentrations from the Facility. Considering future normal operation, Alternative 2 has a greater potential to produce odour than Alternative 1, due to the leachate management system. Alternative 1 will be an above-ground landfill, and thus leachate will drain from each cell (due to gravity) via a sealed drainage system. There will be no opportunity for leachate to pool in the landfill cells. Alternative 2 will make use of a pump system to drain leachate from the landfill cells on an as-needed basis. Managing the odour impacts from Alternative 2 will therefore be more challenging. Alternative 2 also presents a greater risk of an upset condition related to the leachate. Therefore, Alternative 1 is the preferred method when considering odour concentrations. The results of both the net effects analyses and comparative evaluation for Air Quality and Odour will be presented to St. Clair Township, review agencies, First Nations, Métis organizations, and the public for their review and comment prior to conducting the full comparative evaluation of the two Alternatives and identifying a Preferred Alternative. 09ra_ _Net Effects Analysis_Air Quality_ Docx ii

4 Table of Contents Executive Summary 1. Introduction Net Effects Analysis Methodology Evaluation Criteria & Indicators Key Design Considerations & Assumptions Future Baseline Conditions & Assumptions Maximum Impact / Worst-Case Scenario Net Effects Analysis Results Alternative Method 1 Vertical Expansion Alternative Method 2 Southern Expansion Extended Site Life Comparative Evaluation Methodology Comparative Evaluation Results References List of Figures Figure 1. Alternative Figure 2. Alternative Figure 3. Air Emission Source Location Plan Alternative Figure 4. Air Emission Source Location Plan Alternative List of Tables Table 1. Assessment Criteria, Rationale, Indicators and Data Sources... 4 Table 2. Net Effects Analysis Atmospheric Environment - Alternative Method 1 (Vertical Expansion On-Site) Table 3. Alternative Method 2 (Shallow Entombment Off-Site) Table 4. Comparative Evaluation Atmospheric Environment Appendices Appendix A Appendix B Appendix C Glossary of Terms Emission Summary and Dispersion Modelling Report Prepared to Document Alternative Method 1 Evaluation for Environmental Assessment Proposed Lambton Landfill Vertical Expansion Emission Summary and Dispersion Modelling Report Prepared to Document Alternative Method 2 Evaluation for Environmental Assessment - Lambton Landfill Southern Expansion 09ra_ _Net Effects Analysis_Air Quality_ Docx

5 1. Introduction Investigative studies of the following environmental components were carried out as part of the Clean Harbors Lambton Landfill Expansion Environment Assessment (EA) for the purpose of generating a more detailed description and understanding of the existing environment that may potentially be affected by the proposed undertaking: Agriculture Archaeological and Cultural Heritage Atmospheric Environment Geology and Hydrogeology Natural Environment Socio-Economic Surface Water Technical These reports were made available during the EA to St. Clair Township and the appropriate review agencies, First Nations, Métis organizations, and the public for their review and comment. Two expansion alternatives were identified in the approved Terms of Reference (ToR) and developed to a preliminary conceptual design level. Alternative 1 Vertical Expansion On-Site would involve the vertical expansion of the existing landfill site (i.e., expansion would take place over the previously approved and landfilled areas of the site) (see Figure 1). Alternative 2 Shallow Entombment Off-Site would involve the expansion of the site to the south of the existing landfill on adjacent lands already owned by Clean Harbors (see Figure 2). Conceptual designs for these two Alternatives have been further refined in the Conceptual Design Report (CDR), which was made available during the EA to St. Clair Township and the appropriate review agencies, First Nations, Métis organizations, and the public for their review and comment. Following the characterization of the existing environment and further development of the two alternative landfill designs in the CDR, the next step in the EA process is to undertake net effects analyses and a comparative evaluation of the two alternative methods in order to, ultimately, identify a Preferred Alternative. This report utilizes the findings of the Air Quality & Odour Existing Conditions Report, the Emission Summary and Dispersion Modelling (ESDM) Reports, conditions associated with the currently approved landfill at closure, and the CDR to conduct net effects analyses for the two alternatives proposed for the Clean Harbors Lambton Landfill Expansion, in accordance with the methodology outlined in the approved ToR. This report also details the comparative evaluation of the two proposed Alternatives with respect to Air Quality & Odour based on the results of the net effects analyses. The results of both the net effects analyses and the comparative evaluation for Air Quality & Odour will be presented to St. Clair Township, review agencies, First Nations, Métis organizations, and the public for their review and comment prior to conducting the full comparative evaluation of the two Alternatives and identifying a Preferred Alternative. 09ra_ _Net Effects Analysis_Air Quality_ Docx - 1 -

6 TRAILERS CEMETERY PETROLIA LINE TELFER ROAD SURFACE WATER POND SURFACE WATER POND SURFACE WATER BUILDING LEGEND GROUND SURFACE CONTOUR PROPERTY BOUNDARY CURRENT WASTE DISPOSAL LIMIT FENCE PROPOSED BASE CONTOURS PROCESS WATER PROPOSED SURFACE WATER DITCH/POND ALIGNMENT SURFACE WATER FLOW DIRECTION CONCEPTUAL LANDFILL EXPANSION FOOTPRINT EXISTING/PROPOSED SCREENING BERM Lambton Landfill Expansion Alternative Method 1 December 2013 Clean Harbors Canada Inc (021)GN-WA001 DEC 23/2013 Project Figure N E W S

7 196.0 S15 EASTING 393, NORTHING 4,747, ,380 sq.m EASTING 394, NORTHING 4,747, WETLAND WOODLOT CULVERT FOR WOODLOT DRAINAGE WOODLOT m LIMIT OF WASTE PERIMETER ACCESS ROAD 10 m BUFFER FROM PROPERTY LINE TELFER ROAD PROPERTY LINE DRAINAGE DITCH SURFACE WATER DISCHARGE DITCH SURFACE WATER TREATMENT PLANT ROKEBY LINE LEGEND GROUND SURFACE CONTOUR SURFACE WATER 197 DRAINAGE DITCH PROPERTY BOUNDARY TREE N FENCE CONCEPTUAL LANDFILL EXPANSION FOOTPRINT CURRENT WASTE W E DISPOSAL LIMIT EXISTING/PROPOSED WOODED AREA SCREENING BERM S Clean Harbors Canada Inc Lambton Landfill Expansion Alternative Method 2 December 2013 Project Figure (021)GN-WA002 DEC 23/2013

8 2. Net Effects Analysis Methodology With the evaluation criteria, indicators, rationale and data sources confirmed in the approved ToR, the existing conditions characterized and confirmed through the Existing Conditions Report, and the estimated point-of-impingement concentrations (POI) for each air contaminant assessed in the ESDM Reports, a net effects analysis was carried out for each of the alternatives consisting of the following activities: 1. Identify potential effects (based on indicators) on the environment from each alternative in combination with the currently approved landfill considering maximum predicted waste receipt levels (200,000 tonnes of waste per year for approximately 25 years) for the maximum impact stage or worst-case scenario; Based on design considerations and assumptions included in the CDR Document key design considerations and assumptions applicable to air quality and odour (including mitigation measures built into the design) Document future baseline considerations and assumptions applicable to air quality and odour 2. Identify mitigation measures to address potential environmental effects; and Additional mitigation measures beyond those included in the CDR required to further minimize or mitigate identified potential effect(s) associated with the proposed landfill alternatives 3. Identify net environmental effects taking into account mitigation measures. 2.1 Evaluation Criteria & Indicators The approved ToR set out the assessment criteria and indicators for evaluating the alternative methods (i.e., the two alternatives) in the EA. Evaluation criteria were developed for each environmental component listed in the previous section. The criteria and indicators listed in Table 1 were used in the net effects analysis and comparative evaluation for Air Quality & Odour. Table 1. Assessment Criteria, Rationale, Indicators and Data Sources Criteria Rationale Indicators Data Sources AIR QUALITY & ODOUR Air Emissions Waste disposal facilities can emit contaminants that degrade air quality. Construction and operation activities at a waste disposal facility can also lead to increased levels of particulates (dust) in the air. Predicted off-site point of impingement concentrations (g/m 3 ) of indicator compounds. Number of off-site receptors potentially affected (residential properties, public facilities, businesses/farms, institutions). Environment Canada Sarnia Airport meteorological data; MOE meteorological data; Site ambient air monitoring, stack testing and continuous emissions monitoring data; Receptors confirmed on recent mapping; 09ra_ _Net Effects Analysis_Air Quality_ Docx - 4 -

9 Table 1. Assessment Criteria, Rationale, Indicators and Data Sources Odour Criteria Rationale Indicators Data Sources Operation activities at a waste disposal facility can result in odours from the site. Predicted off-site odour concentrations (g/m 3 and odour units). Number of off-site receptors potentially affected (residential properties, public facilities, businesses/farms, institutions). 2.2 Key Design Considerations & Assumptions Sarnia Lambton Environmental Association meteorological data and background air quality data; Waste materials and leachate characterization and sampling data; Emissions Summary and Dispersion Modelling (ESDM) reports; Landfill design and operation data; Landfill expansion alternatives concepts; Proposed facility characteristics. Environment Canada Sarnia Airport meteorological data; MOE meteorological data; Sarnia Lambton Environmental Association meteorological data and background air quality data; Site odour related data; Site odour complaint history; Waste materials and leachate characterization and sampling data; Receptors confirmed on recent mapping; Odour assessment reports; Landfill expansion alternatives concepts; Proposed facility characteristics. The CDR provides the proposed layout of the Facility for each Alternative. The existing Facility process sources of air emissions will remain unchanged for each Alternative; therefore, the key design considerations used for evaluating air quality impacts for each Alternative relate to the location of the proposed landfill, the on-site truck routes and the associated construction activities. Under normal operations, there are currently no off-site odour concentrations from the Facility. Considering future normal operation, Alternative 2 has a greater potential to produce odour than Alternative 1, due to the leachate management system. Alternative 1 will be an above-ground landfill, and thus leachate will drain from each cell (due to gravity) via a sealed drainage system. There will be 09ra_ _Net Effects Analysis_Air Quality_ Docx - 5 -

10 no opportunity for leachate to pool in the landfill cells. Alternative 2 will make use of a pump system to drain leachate from the landfill cells on an as-needed basis. Managing the odour impacts from Alternative 2 will therefore be more challenging. Alternative 2 also presents a greater risk of an upset condition related to the leachate. Potential fugitive dust emissions from the normal, long-term operation for each Alternative were considered based on the new on-site truck routes that would be used for access to the landfill under each alternative, along with the existing Facility truck routes. Additionally, the location of the leachate ponds is different for each Alternative, and thus the location of the leachate pond vent was modelled for each Alternative to determine off-site POI impacts of indicator compounds. Potential fugitive dust emissions from the short-term construction activities for each Alternative were considered to provide further insight into which Alternative is preferred. As detailed in the CDR, construction required for Alternative 2 is more involved than construction required for Alternative 1 and as such, construction activities for Alternative 2 will have greater potential off-site effects from fugitive dust emissions. It should be emphasized that Clean Harbors has a Fugitive Dust and Odour Best Management Plan in place to manage and mitigate fugitive dust emissions from the site and this plan will continue regardless of the Alternative chosen. The management plan will effectively manage and mitigate potential emissions of particulate, and therefore these emissions were not assessed quantitatively. Construction activities required for each Alternative are described in the following sections. For Alternative 1, no cover would be placed over the existing landfill until the working landfill cell is complete (approximately 3 years for the pre-1986 subcell area). Actual landfilling activity would be the same as existing conditions. There would be some soil movement occurring on a monthly basis. Soil and earth moving activities have the potential to create fugitive dust emissions, which would need to be addressed by the Facility as part of their Fugitive Dust and Odour Best Management Plan. For Alternative 2, all of the southern berm would be constructed initially except for approximately 350 m of the eastern portion. The berm, stormwater pond and ditches, relocation of the northwest pond, south process water pond, and south leachate pond would all be a part of initial construction. Cells would be excavated as required based on the landfilling rate. Soil and earth moving activities have the potential to create fugitive dust emissions, which would need to be addressed by the Facility as part of their Fugitive Dust and Odour Best Management Plan. Under this Alternative, there would also be potential for stockpiles of excavated material. Stockpiles may generate fugitive dust emissions because they are susceptible to wind erosion. The Facility would need to include management and mitigation of the stockpiles in the Fugitive Dust and Odour Best Management Plan. As such, Alternative 2 would require additional mitigation measures with regard to fugitive dust than Alternative Future Baseline Conditions & Assumptions The Existing Conditions Report prepared in the previous stage of the EA process provides a complete inventory of the environmental conditions within the Clean Harbors Lambton Landfill Facility Expansion Study Area at a particular point in time (approximately 2012) and reflect the current operation of the existing Clean Harbors Lambton Facility. In order to predict potential environmental effects resulting from each of the proposed alternative methods, the analysis must consider the Study Area s existing conditions at the time of development 09ra_ _Net Effects Analysis_Air Quality_ Docx - 6 -

11 of the proposed alternatives. These are referred to as the future baseline conditions. At the future baseline year the currently approved Lambton Landfill will be closed; however, all other on-site waste management activities will continue. As per the Closure Plan described in the Lambton Landfill Design and Operational Report (March 2010), upon closure of the landfill, the landfill cap will be constructed to its final elevation and contours, covered with topsoil and vegetative cover will be established. Access roads, other earthen works (such as berms, drainage ditches and swales, surface water reservoirs, etc.), surface water runoff collection, treatment and discharge, and noise, dust and lighting abatement measures will be maintained as they were during the operational life of the landfill. The Future Baseline Conditions have been considered in the evaluation of the net effects for the Alternative Methods. For each Alternative, the air dispersion modelling in the ESDM Report in Appendix B and C includes the existing Facility sources and the proposed landfill. The existing landfill has not been included in the evaluation of net effects, as the assumption is that it will be closed and capped with no further emissions. 2.4 Maximum Impact / Worst-Case Scenario The ToR states that potential environmental effects will be evaluated considering maximum predicted waste receipt levels. During the period from 2001 to 2010, Clean Harbors landfilled an average of 170,000 tonnes of waste per year. Clean Harbors anticipates that the maximum future waste receipt rate will be comparable to past years and, as such, the net effects analysis considered a conservative maximum predicted waste receipt level of 200,000 tonnes of waste per year for a site life of approximately 25 years. An ESDM Report was prepared for each Alternative to predict the potential maximum point-of-impingement (POI) concentrations based on the operating conditions which considered the maximum predicted waste receipt levels and included all Facility air emission sources operating simultaneously at their individual maximum rates of production. The Facility was assessed from the ground up to determine all potential sources of air emissions. These sources are documented in detail in the ESDM Reports, and include the Thermal Desorption Unit (TDU) and support processes, Facility laboratory exhausts, the incinerator stack and pre-treatment system tanks, the land disposal restrictions (LDR) baghouse, and fugitive emission sources. The Facility emission sources and locations are shown on Figure 3 and Figure 4 for Alternative 1 and Alternative 2, respectively. Each source was assessed individually to determine potential air contaminant emissions, and in each case an appropriate estimation methodology was selected. Methods used include stack testing, mass balance calculations, engineering calculations, and published emission factors. Potential compounds emitted from the Facility include volatile organic compounds (VOCs), products of combustion, particulate matter, metals, and polychlorinated biphenyls (PCBs). A complete listing of all compounds is provided in the ESDM Reports. The potential maximum emission rates for each contaminant emitted from the Facility sources were calculated in accordance with Section 11 of O. Reg. 419/05 Air Pollution Local Air Quality. In addition to considering the maximum predicted waste receipt levels, the net effects analysis was carried out for the maximum impact stage or worst-case scenario for each Alternative. This is a very conservative analysis and results in POI concentrations below the standards in the O. Reg. 419/05 criteria. 09ra_ _Net Effects Analysis_Air Quality_ Docx - 7 -

12 (007)GIS-WA001 December 02, 2013 ² m :4,100 UTM Zone 17N, NAD 83 Legend Clean Harbors Canada Inc. Air Quality & Odour Net Effects Analysis & Comparative Evaluation Report December 2013 Project Figure 3

13 (007)GIS-WA002 December 02, 2013 ² m :8,200 UTM Zone 17N, NAD 83 Legend Clean Harbors Canada Inc. Air Quality & Odour Net Effects Analysis & Comparative Evaluation Report December 2013 Project Figure 4

14 For Alternative 1, the on-site haul roads will change over time depending on where the working landfill face is located. The potential worst-case scenario for road dust was identified to occur when the working landfill face is located to the west of the existing landfill face. The worst-case on-site truck routes for Alternative 1 are presented on Figure 3. This was incorporated into the ESDM Report to evaluate the potential worst-case future off-site concentrations for Alternative 1. For Alternative 2, the on-site haul roads will change over time depending on where the working landfill face is located. The potential worst-case scenario for road dust was identified as being at the beginning of the landfill life when the working landfill face will be located at the point furthest south from the existing Facility (longest haul road); this was incorporated into the ESDM Report to assess the potential worst-case future off-site concentrations for Alternative 2. Under this alternative, the leachate ponds and the carbon pits would be relocated south of the existing Facility. These sources emit volatile organic compounds which are indicator compounds assessed in the ESDM Reports. 3. Net Effects Analysis Results As previously discussed, the net effects analysis was conducted by documenting potential effects associated with each indicator for the maximum impact stage or worst-case scenario. Mitigation measures were identified to avoid or minimize potential effects and then the net effects were evaluated taking into consideration the application of mitigation measures. The results of this net effects analysis for Alternative 1 and Alternative 2 are described in the following sections. The AERMOD dispersion model was used to predict potential effects on air quality at receptors within 5 km of the Study Area boundary in addition to receptors located within the Aamjiwnaang First Nations lands. Receptors were chosen based on recommendations provided in Section 7.1 of the Air Dispersion Modelling Guideline for Ontario, which is in accordance with s.14 of O. Reg. 419/05. Specifically, a nested receptor grid was used, based on an area that is bounded by a rectangle that encloses every source of contaminants, and spaced out as follows: 20 m spacing within a distance of 200 m from the bounding rectangle 50 m spacing from 200 m to 500 m from the bounding rectangle 100 m spacing from 500 m to 1,000 m from the bounding rectangle 200 m spacing from 1,000 m to 2,000 m from the bounding rectangle 500 m spacing from 2,000 m to 5,000 m from the bounding rectangle In addition to the nested receptor grid, receptors were also placed every 10 m along the property line. No receptors were located within the Lambton Landfill property line. As there is no childcare facility, health care facility, seniors residence, long-term care facility, or educational facility located at the Facility, same structure contamination was not considered. Receptors within the Aamjiwnaang First Nation lands were located using a uniform discrete receptor grid with 100 m spacing within the community. In addition to the discrete receptor grid, receptors were placed every 10 m along the edges of the Aamjiwnaang First Nation boundary. 09ra_ _Net Effects Analysis_Air Quality_ Docx

15 With the receptors identified in accordance with O. Reg. 419/05, the AERMOD air dispersion model then calculated the predicted maximum off-site POI concentration for each indicator compound. A list of these compounds and associated concentrations is provided in Appendix B and C for review. The following sections provide the results of the net effects analysis as it relates to the indicators identified in the approved Terms of Reference for the proposed Lambton Landfill Expansion. 3.1 Alternative Method 1 Vertical Expansion As the same methodology for identifying receptors was used for both Alternative 1 and 2, the total number of receptors potentially affected by off-site POI concentrations and off-site odour concentrations would be the same. Given that the air dispersion model uses a nested receptor grid, as described in Section 3, to identify the maximum off-site POI concentrations, and the grid used is the same for the assessment of each Alternative, all potential receptors within the grid were included in the evaluation and assessed. It is important to note that for Alternative 1, the receptors that are in the closest vicinity to the proposed landfill are already in the vicinity of the existing landfill, and the net change in impacts would not be significant compared to the net change in impacts for Alternative 2. The predicted off-site POI concentrations of over 150 indicator compounds assessed for Alternative 1 were compared against criteria listed in the Ministry publication "Summary of Standards and Guidelines to Support Ontario Regulation 419/05 Air Pollution Local Air Quality" dated April The air emissions from the Facility result in predicted POI concentrations of indicator compounds that are all below their respective O. Reg. 419/05 criteria. Potential fugitive dust emissions from the short-term construction activities for Alternative 1 were considered to provide further insight into which Alternative is preferred. For Alternative 1, no cover would be placed over the existing landfill until the working landfill cell is complete (approximately 3 years for the pre-1986 subcell area). Actual landfilling activity would be the same as existing conditions. There would be some soil movement occurring on a monthly basis. Soil and earth moving activities have the potential to create fugitive dust emissions, which would need to be addressed by the Facility as part of their Fugitive Dust and Odour Best Management. It should be emphasized that Clean Harbors has an existing Fugitive Dust and Odour Best Management in place to manage and mitigate fugitive dust emissions from the site, and this plan will continue regardless of the Alternative chosen. The management plan will effectively manage and mitigate potential emissions of particulate, and therefore these emissions were not assessed quantitatively. Under normal operations, there are no off-site odour concentrations from the Facility. As Clean Harbors will continue with their existing practices for managing odour, it is anticipated that there will be no off-site odour concentrations from the Facility under normal operations. 3.2 Alternative Method 2 Southern Expansion As previously described, the total number of receptors modelled for each alternative are the same given the implementation of the nested receptor grid used in the assessment. It is important to note that for Alternative 2, the receptors that are in the closest vicinity to the proposed landfill are not currently in the vicinity of the existing landfill, and the net change in impacts at these receptors would therefore be more significant than the net change for Alternative 1. 09ra_ _Net Effects Analysis_Air Quality_ Docx

16 The predicted off-site POI concentrations of over 150 indicator compounds assessed for Alternative 2 were compared against criteria listed in the Ministry publication "Summary of Standards and Guidelines to Support Ontario Regulation 419/05 Air Pollution Local Air Quality" dated April The air emissions from the Facility result in predicted POI concentrations of indicator compounds that are all below their respective O. Reg. 419/05 criteria. Potential fugitive dust emissions from the short-term construction activities for Alternative 2 were considered to provide further insight into which Alternative is preferred. For Alternative 2, all of the southern berm would be constructed initially except for approximately 350 m of the eastern portion. The berm, stormwater pond and ditches, relocation of the northwest pond, south process water pond, and south leachate pond would all be a part of initial construction. Cells would be excavated as required based on the landfilling rate. Soil and earth moving activities have the potential to create fugitive dust emissions, which would need to be addressed by the Facility as part of their Fugitive Dust and Odour Best Management. Under this Alternative, there would also be potential for stockpiles of excavated material. Stockpiles may generate fugitive dust emissions because they are susceptible to wind erosion. As such, potential off-site POI impacts from construction activities would be higher for Alternative 2 as a greater degree of construction is required. The Facility would need to include management and mitigation of the stockpiles in the Fugitive Dust and Odour Best Management. It should be emphasized that Clean Harbors has an existing Fugitive Dust and Odour Best Management in place to manage and mitigate fugitive dust emissions from the site, and this plan will continue regardless of the Alternative chosen. The management plan will effectively manage and mitigate potential emissions of particulate, and therefore these emissions were not assessed quantitatively. Under normal operations, there are no off-site odour concentrations from the Facility. As Clean Harbors intends to continue with their existing practices for managing odour, it is anticipated that there will continue to be no off-site odour concentrations from the Facility under normal operations. 09ra_ _Net Effects Analysis_Air Quality_ Docx

17 Table 2. Net Effects Analysis Atmospheric Environment - Alternative Method 1 (Vertical Expansion On-Site) Environmental Component Atmospheric Environment Criteria Air Emissions Odour Indicators Predicted off-site point of impingement concentrations (µg/m3) of indicator compounds. Number of off-site receptors potentially affected (residential properties, public facilities, businesses/farms, and institutions). Predicted off-site odour concentrations (µg/m3 and odour units). Number of off-site receptors potentially affected (residential properties, public facilities, businesses/ farms, and institutions). Key Design Considerations & Assumptions Existing Facility process sources of air emissions will remain unchanged. Key design considerations used for evaluating air quality impacts relate to the location of the proposed landfill, the on-site truck routes and the associated construction activities. Some soil movement will occur on a monthly basis. AERMOD dispersion model was used to predict potential effects on air quality at receptors within 5 km of the Study Area boundary in addition to receptors located within the Aamjiwnaang First Nations lands. Clean Harbors maintains and will continue to implement the existing Fugitive Dust and Odour Best Management Plan. AERMOD dispersion model was used to predict potential effects on air quality at receptors within 5 km of the Study Area boundary in addition to receptors located within the Aamjiwnaang First Nations lands. Future Baseline Considerations & Assumptions The air dispersion modelling in the ESDM Reports include the existing Facility sources and the proposed landfill. The existing landfill has not been included in the evaluation, as the assumption is that it will be closed and capped with no further emissions. The air dispersion modelling in the ESDM Reports include the existing Facility sources and the proposed landfill. The existing landfill has not been included in the evaluation, as the assumption is that it will be closed and capped with no further emissions. Clean Harbors will continue to implement the existing Fugitive Dust and Odour Best Management Plan. The air dispersion modelling in the ESDM Reports include the existing Facility sources and the proposed landfill. The existing landfill has not been included in the evaluation, as the assumption is that it will be closed and capped with no further emissions. Potential Effects Mitigation Measures Net Effects Predicted off-site POI concentrations of over 150 indicator compounds assessed were compared against MOE criteria and resulted in predicted POI concentrations of indicator compounds that are all below their respective standards. Alternative 1 has slightly higher potential off-site POI concentrations than Alternative 2; however, the difference is not considered substantial. Soil and earth moving activities have the potential to create fugitive dust emissions during the short-term construction activities. As the same methodology for identifying receptors was used for both Alternative 1 and 2, the total number of receptors potentially affected by off-site POI concentrations would be the same. Under normal operations, there are no off-site odour concentrations from the Facility and therefore, there are no potential effects anticipated. As the same methodology for identifying receptors was used for both Alternative 1 and 2, the total number of receptors potentially affected by off-site odour concentrations would be the same. As all POI concentrations of indicator compounds are below their respective standards, no mitigation measures are required. Continue with the implementation of the existing fugitive dust best management program to manage and mitigate potential emissions of particulate. None required. Clean Harbors will continue to implement the Fugitive Dust and Odour Best Management Plan. None required. Although Alternative 1 has slightly higher potential off-site POI concentrations than Alternative 2; the difference is not considered substantial and all potential offsite air quality impacts from the Facility comply with the MOE health and risk based Air Quality Standards. Furthermore, fugitive dust emissions will be mitigated through the implementation of the fugitive dust best management program. As such, no net effects from air emissions are anticipated. Although the total number of receptors potentially affected by off-site POI concentrations would be the same for each Alternative, the receptors that are closest to the proposed landfill are already in the vicinity of the existing landfill, and the net change in effects is not considered significant. Under normal operations, there are currently no off-site odour impacts from the Facility. As such, no net effects from odour are anticipated. Under normal operations, there are currently no off-site odour impacts from the Facility; however, under an upset scenario in the future, potential off-site odour concentrations would be the same for either Alternative. As such, no net effects from odour are anticipated. 09ra_ _Net Effects Analysis_Air Quality_ Docx

18 Table 3. Alternative Method 2 (Shallow Entombment Off-Site) Environmental Component Atmospheric Environment Criteria Air Emissions Odour Indicators Predicted off-site point of impingement concentrations (µg/m 3 ) of indicator compounds. Number of off-site receptors potentially affected (residential properties, public facilities, businesses/farms, and institutions). Predicted off-site odour concentrations (µg/m 3 and odour units). Number of off-site receptors potentially affected (residential properties, public facilities, businesses/farms, and institutions). Key Design Considerations & Assumptions Existing Facility process sources of air emissions will remain unchanged Key design considerations used for evaluating air quality impacts relate to the location of the proposed landfill, the on-site truck routes and the associated construction activities All of the southern berm would be constructed initially except for approximately 350 m of the eastern portion The berm, stormwater pond and ditches, relocation of the northwest pond, south process water pond, and south leachate pond would all be a part of initial construction. Cells would be excavated as required based on the landfilling rate AERMOD dispersion model was used to predict potential effects on air quality at receptors within 5 km of the Study Area boundary in addition to receptors located within the Aamjiwnaang First Nations lands. Clean Harbors maintains and will continue to implement the existing Fugitive Dust and Odour Best Management Plan. AERMOD dispersion model was used to predict potential effects on air quality at receptors within 5 km of the Study Area boundary in addition to receptors located within the Aamjiwnaang First Nations lands. Future Baseline Considerations & Assumptions The air dispersion modelling in the ESDM Reports include the existing Facility sources and the proposed landfill. The existing landfill has not been included in the evaluation, as the assumption is that it will be closed and capped with no further emissions. The air dispersion modelling in the ESDM Reports include the existing Facility sources and the proposed landfill. The existing landfill has not been included in the evaluation, as the assumption is that it will be closed and capped with no further emissions. Clean Harbors will continue to implement the existing Fugitive Dust and Odour Best Management Plan. The air dispersion modelling in the ESDM Reports include the existing Facility sources and the proposed landfill. The existing landfill has not been included in the evaluation, as the assumption is that it will be closed and capped with no further emissions. Potential Effects Mitigation Measures Net Effects Predicted off-site POI concentrations of over 150 indicator compounds assessed were compared against MOE criteria and resulted in predicted POI concentrations of indicator compounds that are all below their respective standards. Soil and earth moving activities have the potential to create fugitive dust emissions during the short-term construction activities and potential off-site POI impacts from construction activities would be higher for Alternative 2 as a greater degree of construction is required. As the same methodology for identifying receptors was used for both Alternative 1 and 2, the total number of receptors potentially affected by off-site POI concentrations would be the same. Under normal operations, there are no off-site odour concentrations from the Facility and therefore, there are no potential effects anticipated. As the same methodology for identifying receptors was used for both Alternative 1 and 2, the total number of receptors potentially affected by off-site odour concentrations would be the same. As all POI concentrations of indicator compounds are below their respective standards, no mitigation measures are required. Continue with the implementation of the existing fugitive dust best management program to manage and mitigate potential emissions of particulate. None required. Clean Harbors will continue to implement the existing Fugitive Dust and Odour Best Management Plan. All potential off-site air quality impacts from the Facility comply with the MOE health and risk based Air Quality Standards and fugitive dust emissions will be mitigated through the implementation of the fugitive dust best management program. As such, no net effects from air emissions are anticipated. Although the total number of receptors potentially affected by off-site POI concentrations would be the same for each Alternative, the receptors that are the closest to the proposed landfill are not currently in the vicinity of the existing landfill, and the net change in effects at these receptors is therefore more significant than the net change for Alternative 1. Under normal operations, there are currently no off-site odour impacts from the Facility. As such, no net effects from odour are anticipated. None required. Under normal operations, there are currently no off-site odour impacts from the Facility; however, under an upset scenario in the future, potential off-site odour concentrations would be the same for either Alternative. As such, no net effects from odour are anticipated. 09ra_ _Net Effects Analysis_Air Quality_ Docx

19 3.3 Extended Site Life It is possible that actual waste volumes received annually at the Lambton Landfill might be lower than the volumes predicted and, if so, that the landfill might operate beyond the 25 year planning period. As such, it is also important to consider the net environmental effects in the context of the landfill lasting beyond 25 years. The ESDM Reports represent the potential maximum worst-case scenario for each Alternative. These potential worst-case net effects are therefore still representative of the potential net effects for an extended site life at an average waste receipt rate of 130,000 tonnes per year. 4. Comparative Evaluation Methodology The net environmental effects identified and documented in the net effects analysis for a 25 year site life were then utilized in a comparison of the two alternatives to one another at the indicator and criteria level for each discipline. The following two step methodology was applied in order to carry out the comparative evaluation for Air Quality & Odour: 1. Identify the predicted net effect(s) associated with each alternative for each indicator and assign a preference rating (i.e., Preferred, Not Preferred, No Substantial Difference); and 2. Rate each alternative at the criteria level (i.e., Preferred, Not Preferred, No Substantial Difference) based on the identified preference rating for each indicator and provide a rationale 5. Comparative Evaluation Results For normal, long term Facility operation, Alternative 1 has slightly elevated potential off-site POI concentrations for a few compounds when compared to the results for Alternative 2; however, the difference is relatively minor and both Alternatives comply with the O. Reg. 419/05 criteria. Therefore, there is no clear preferred Alternative when considering POI concentrations alone. Potential fugitive dust emissions from the short-term construction activities for each Alternative were considered to provide further insight into which Alternative is preferred. As detailed in the CDR, construction required for Alternative 2 is more involved than construction required for Alternative 1 and as such, construction activities for Alternative 2 will have greater potential off-site effects. However, as previously noted, Clean Harbors has an existing Fugitive Dust and Odour Best Management Plan in place to manage and mitigate fugitive dust emissions from the site and this plan will continue regardless of the Alternative chosen. The management plan will effectively manage and mitigate potential emissions of particulate, and therefore these emissions were not assessed quantitatively. Alternative 2 would require further mitigation measures than Alternative 1. Therefore, when considering short-term construction activities, Alternative 1 is the preferred Alternative. Under normal operations, there are currently no off-site odour concentrations from the Facility. Considering future normal operation, Alternative 2 has a greater potential to produce odour than Alternative 1, due to the leachate management system. Alternative 1 will be an above-ground landfill, 09ra_ _Net Effects Analysis_Air Quality_ Docx