AIR QUALITY IMPACT ASSESSMENT FOR THE MONDI MILL MODIFICATION, RICHARDS BAY

Transcription

1 Project completed on behalf of SRK Consulting AIR QUALITY IMPACT ASSESSMENT FOR THE MONDI MILL MODIFICATION, RICHARDS BAY Report No.: APP/10/SRK-10 Rev 5 DATE: May 2011 Authors: GT Feig G Kornelius

2 Reference APP/10/SRK/10 Status Revision 5 Report Title Date June 2011 Client Prepared by Notice Declaration Copyright Warning Acknowledgements REPORT DETAILS Air Quality Impact Assessment for the third steam turbine at Mondi Richards Bay SRK Consulting Gregor T. Feig, PhD (Biogeochemistry, Mainz, IMPRS) Gerrit Kornelius PrEng PhD MBA BEng(Hons)(Chem) (Pretoria) Airshed Planning Professionals (Pty) Ltd is a consulting company located in Midrand, South Africa, specialising in all aspects of air quality, ranging from nearby neighbourhood concerns to regional air pollution impacts. The company originated in 1990 as Environmental Management Services, which amalgamated with its sister company, Matrix Environmental Consultants, in Airshed is an independent consulting firm with no interest in the project other than to fulfil the contract between the client and the consultant for delivery of specialised services as stipulated in the terms of reference. Unless otherwise noted, the copyright in all text and other matter (including the manner of presentation) is the exclusive property of Airshed Planning Professionals (Pty) Ltd. It is a criminal offence to reproduce and/or use, without written consent, any matter, technical procedure and/or technique contained in this document. We would like to thank Natalie Way-Jones from SRK Consulting for the help in preparing this report.

3 LIST OF ACRONYMS AND ABBREVIATIONS ACS American Cancer Society AQA Air Quality Act (South African) CAPCO Chief Air Pollution Control Officer DEA Department of Environmental Affairs. EC European Community EHS Environmental Health and Safety Guideline (WHO) EIA Environmental Impact Assessment g Gram GIIP Good International Industry Practice h Hour IFC International Finance Corporation of the World Bank IT Interim Target km Kilometre m Metre Mg Mega gram (10 3 kg) NA Not applicable NAAQS (SA) National Ambient Air Quality Standards ng nanogram (10 12 kg) PM 10 Particulate Matter with an aerodynamic diameter of less than 10 µm RBCAA Richards Bay Clean Air Association SABS South African Bureau of Standards SANS South African National Standard SAWS South African Weather Service TPA, tpa Mg per annum (10 3 kg/annum) TSP Total suspended Particulate, generally accepted as aerosols < 30 micron diameter UK United Kingdom µm Micron US EPA United States Environmental Protection Agency US EPA IRIS United States Integrated Risk Information System WHO World Health Organisation ii

4 Executive Summary Airshed Planning Professionals (Pty) Ltd was appointed by SRK Consulting to undertake an air quality impact assessment for the proposed modification of the power boiler facility and the installation of a chlorine dioxide storage facility at the Mondi Richards Bay pulp and paper mill. The proposed power boiler facility modification will consist of the refurbishment of the two existing coal fired boilers and the installation of a third steam turbine for the production of electricity, provision will be made for one of the boilers to be converted into a biomass boiler in the future. The chlorine dioxide facility will consist of two 250m³ above ground closed tanks. The aim of the investigation is to quantify the possible impacts resulting from the energy generating activities on the surrounding environment and on human health. To achieve this, a good understanding of the regional climate and local dispersion potential of the site is necessary. The primary pollutants of concern are the emissions of sulphur dioxide (SO 2 ) and oxides of nitrogen (NO x ) and particulate matter (PM 10 ) emissions from power generation activity. This study focused on the air quality impacts of the proposed Mondi Richards Bay modification including: Understanding the dispersion potential of the site based on regional meteorological data; Identification and quantification of all sources of air pollution from the steam boiler modification and from the construction of a 500m³ ClO 2 storage facility; Dispersion simulations to determine the impact zones from the refurbished steam boilers; Identification of the main sources of emission and impact and ranking of these sources for the purpose of mitigation measures to be implemented; and, Mitigation recommendations and management measures. Summary ClO 2 Storage Tank If the design of the chlorine dioxide storage tank meets the emission requirements of the National emission standards (HCl emission of 15mg/Nm³) it will be in accordance with the NEM:AQA. The ClO 2 storage tanks are sealed and not expected to release HCl. iii

5 Incremental Impact (Mondi Sources Only) Sulphur Dioxide (SO 2 ) The SO 2 emissions from the modified boilers at the Mondi Richards Bay facility are expected to reach a maximum of 2932 Mg/annum if the national emission limits are met. This is approximately 10.5% of the total annual SO 2 emission for the Richards Bay area. The Phase 1 scenario is expected to result in reduced ambient SO 2 concentrations due to the reduced SO 2 emission concentration and the lower total amount of SO 2 released annually. The direct impact of both the current and phase 1 operations at the power boilers is expected to be low, less than 10%, 25% and 34% of the annual, daily and hourly NAAQS standards respectively. Nitrogen Dioxide (NO 2 ) The scenarios show a significant difference in the NO 2 emissions between the current and Phase 1 boiler scenarios where the current NO 2 emission rate is 638.9Mg/annum and the phase 1 emission rate is expected to be 4383Mg/annum. This difference is due to the fact that the emission limits were used to determine the emission rate and probably represents an over estimation of what the actual emissions will be. The highest annual average ambient NO 2 concentration is expected to account for 4% of the NAAQS (National Ambient Air Quality Standard) under the current scenario and 15% of the NAAQS under the phase 1 scenario. For the hourly averaging period the highest NO 2 concentration from the current emissions is expected to be less than 15% of the NAAQS, while the highest hour from the Phase 1 scenario is expected to exceed the National standard but for less than the allowed 88 hours per year. Particulate matter (PM 10 ) The emissions of particulate matter from the modified Mondi Power boiler are expected to account for 7% of the total PM 10 emissions in the Richards Bay area. The impact from the modified boilers is likely to be small, less than 15% of the NAAQS for both the highest daily and annual averaging period. If the Phase 2 scenario is implemented it is expected that there will be a further reduction in the local PM 10 concentration due to the expected reduction in material handling related emissions. Cumulative Impact (Mondi Sources and Background) Sulphur Dioxide (SO 2 ) The cumulative impact of SO 2, where the other Richards Bay sources are included, shows exceedances of the NAAQS in the annual, daily and hourly averaging periods, From a study of the position of the areas of exceedance relative to the major sources and the individual impact of the Mondi Richards Bay power boiler sources, it is concluded that these exceedances are due to sources other than the Mondi Richards Bay power boilers. iv

6 Nitrogen Dioxide (NO 2 ) The cumulative NO 2 concentration does not show any exceedances of the NAAQS under either the current or the phase 1 scenarios for the annual averaging period, however there are exceedances in the hourly averaging period current and phase 1 scenarios although the number of exceedances is less than the 88 allowed annually. Particulate Matter When the cumulative impact of PM 10 is considered, exceedances of the NAAQS occur for both the annual and daily averaging periods. When the cumulative impacts are considered there are areas in exceedance of the NAAQS standards. From a study of the position of the areas of exceedance relative to the major sources and the individual impact of the Mondi Richards Bay power boiler sources, it is concluded that these exceedances are due to sources other than the Mondi Richards Bay power boilers. Conclusion The proposed modification of the power boilers at the Mondi Richards bay facility is likely to have a limited impact on the ambient air quality in the Richards Bay region, if the emission standards are met. Of the three pollutants that were considered during this study the greatest impact would be on the NO 2 concentrations, however this is a very conservative scenario using the national emission limits to determine the emission rate. There is expected to be a local increase in the PM 10 concentrations, mostly due to the increased coal handling to power the boilers, this however is likely to be reduced during the second phase of the modification when biomass is used as a fuel source. The ambient SO 2 concentrations are expected to decrease slightly with the modification if the national emission standards are met. v

7 Table of Contents LIST OF ACRONYMS AND ABBREVIATIONS...ii Summary...iii ClO 2 Storage Tank...iii Incremental Impact (Mondi Sources Only)...iv Cumulative Impact (Mondi Sources and Background)...iv Conclusion...v 1 Introduction Terms of Reference Project Description Outline of Report Methodology Site Description Sensitive Receptors Emissions Inventory Dispersion Model Methodology Dispersion Modelling Results Assumptions Legislative Overview of Air Quality Standards South African Legal Requirements According to the Air Quality Act No.39 of National Ambient Air Quality Standards Listed Activities which may result in Air pollution BASELINE CHARACTERISATION Meteorological conditions Prevailing Synoptic Climatology Local Meteorology Surface Wind Field Temperature Precipitation vi

8 4.3.4 Mixing Height and Atmospheric Stability Existing sources Sources of Atmospheric Emissions Existing Sources of Emissions within the City of umhlathuze Ambient Air Quality Monitoring carried out in Richards Bay Impact Assessment Emissions inventory Chlorine Dioxide Storage Tank Stack emissions Material Handling Emissions Dispersion modelling results Sulphur Dioxide Concentrations Nitrogen Dioxide Concentrations Particulate Matter Summary and Conclusion Summary ClO 2 Storage Tank Incremental Impact (Mondi Sources Only) Cumulative Impact (Mondi Sources and Background) Conclusion References Appendix A: Methodology Calculation of Emission Factors Materials handling (confidence rating C- average) vii

9 Figures Figure 4-1: Major synoptic circulation types affecting southern Africa and their monthly frequencies of occurrence over a five year period (Preston-Whyte and Tyson 1988) Figure 4-2: Location of the five ambient monitoring stations within the study area (SGS 2010) Figure 4-3: Annual average wind roses depicting the wind profile at the RBCAA stations for the period January 2008 to December Figure 4-4 Annual Wind roses for 2009 and 2010 for the meteorological station at Arboretum (SGS 2010) Figure 4-5 Temperature Profile for Richards Bay (SGS 2010) Figure 4-6: & Petzer, 2006) 4-13 Location of all the main industries and mines within the area (after Liebenberg-Enslin Figure 4-7: Location of the five SO 2 ambient monitoring stations within the study area Figure 4-8 Comparison of annual average SO2 for the period Figure 4-9 Daily average SO 2 concentration measured at Arboretum during Figure 4-10 Daily average SO 2 concentration measured at Arboretum during Figure 4-11 Daily average SO 2 concentration measured at Arboretum during 2010 (SGS 2010) Figure 4-12 Daily average SO 2 concentration measured at Brackenham during Figure 4-13 Daily average SO 2 concentration measured at Brackenham during Figure 4-14 Daily average SO 2 concentration measured at Brackenham during 2010 (SGS 2010) Figure 4-15 Daily average SO 2 concentration measured at CBD during Figure 4-16 Daily average SO 2 concentration measured at CBD during Figure 4-17 Daily average SO 2 concentration measured at CBD during 2010 (SGS 2010) Figure 4-18 Daily average SO 2 concentration measured at Scorpio substation (cnr John Ross and West Central Arterial) during viii

10 Figure 4-19 Daily average SO 2 concentration measured at Scorpio substation (cnr John Ross and West Central Arterial) during Figure 4-20 Daily average SO 2 concentration measured at Scorpio substation (cnr John Ross and West Central Arterial) during Figure 4-21 Daily average SO 2 concentration measured at Harbour West during Figure 4-22 Daily average SO 2 concentration measured at Harbour West during Figure 4-23 Daily average SO 2 concentration measured at Harbour West during 2010(SGS 2010) 4-28 Figure 4-24 Daily average PM 10 concentrations at the CBD during Figure 4-25 Daily average PM 10 concentrations at the CBD during Figure 4-26 Daily average PM 10 concentrations at Brackenham during Figure 4-27 Daily average PM 10 concentrations at Brackenham during Figure 5-1 Annual average SO 2 concentrations due to current Mondi Boiler operations (contours represent 0.38ppb blue, 0.76ppb green, 1.15ppb magenta and 1.53ppb orange) Figure 5-2 Annual average SO 2 concentrations Mondi Phase 1 sources only (contours represent 0.38ppb blue, 0.76ppb green, 1.15ppb magenta and 1.53ppb orange) Figure 5-3 Annual average SO 2 concentrations due to actual Mondi Boiler operations for 2010 (contours represent 0.38ppb blue, 0.76ppb green, 1.15ppb magenta and 1.53ppb orange) Figure 5-4 Annual cumulative SO 2 concentrations (Mondi current and background) Figure 5-5 Annual cumulative SO 2 concentrations (Mondi Phase1 and background) Figure 5-6 Annual cumulative SO 2 concentrations, Mondi actual 2010 and background) Figure 5-7 Highest Daily SO 2 concentrations, current Mondi boiler sources only. Contours represent 1.9ppb (blue), 3.8ppb (green), 5.8ppb (magenta) and 7.7ppb (orange) Figure 5-8 Highest Daily SO 2 concentrations, Mondi Phase 1 sources only. Contours represent 1.9ppb (blue), 3.8ppb (green), 5.8ppb (magenta) and 7.7ppb (orange) Figure 5-9 Highest Daily SO 2 concentrations, actual 2010 emissions Mondi boiler sources only. Contours represent 1.9ppb (blue), 3.8ppb (green), 5.8ppb (magenta) and 7.7ppb (orange) ix

11 Figure 5-10 Highest Daily SO 2 concentrations, Mondi current and background sources. Contours represent 28.8ppb (blue), 46.1ppb (green), 76.8ppb (magenta) and 115.2ppb (orange) Figure 5-11 Highest Daily SO 2 concentrations, Mondi Phase1 and background sources. Contours represent 28.8ppb (blue), 46.1ppb (green), 76.8ppb (magenta) and 115.2ppb (orange) Figure 5-12 Highest Daily SO 2 concentrations, Mondi 2010 actual and background sources. Contours represent 28.8ppb (blue), 46.1ppb (green), 76.8ppb (magenta) and 115.2ppb (orange) Figure 5-13 SO 2 Daily frequency of exceedance of the South African National Ambient Air Quality standard of 125 µg/m³ (48ppb), Baseline + Current contour represents area where standard is exceeded more than 4 days per annum Figure 5-14 SO 2 Daily frequency of exceedance of the South African National Ambient Air Quality standard of 125 µg/m³ (48ppb), Baseline + Phase 1 contour represents area where standard is exceeded more than 4 days per annum Figure 5-15 Pollution Rose for SO 2 for the Scorpio station 2010 (SGS 2010) Figure 5-16 Highest hourly SO 2 concentrations due to current Mondi activities. Contour lines represent 9.6ppb (blue), 19.2 ppb (green), 28.8 ppb (magenta) and 38.5ppb (orange) Figure 5-17 Highest hourly SO 2 concentrations due to Phase 1 activities. Contour lines represent 9.6ppb (blue), 19.2 ppb (green), 28.8 ppb (magenta) and 38.5ppb (orange) Figure 5-18 Highest hourly SO 2 concentrations due to the actual Mondi boiler activities in Contour lines represent 9.6ppb (blue), 19.2 ppb (green), 28.8 ppb (magenta) and 38.5ppb (orange) Figure 5-19 Cumulative highest hourly SO 2 concentrations, Mondi current and background sources. Contours represent 67ppb (blue), 134ppb (green), 193ppb (magenta) and 269ppb (orange) Figure 5-20 Cumulative highest hourly SO 2 concentrations, Mondi Phase1 and background sources. Contours represent 67ppb (blue), 134ppb (green), 193ppb (magenta) and 269ppb (orange) Figure 5-21 Cumulative highest hourly SO 2 concentrations, Mondi actual 2010 and background sources. Contours represent 67ppb (blue), 134ppb (green), 193ppb (magenta) and 269ppb (orange) Figure 5-22 Frequency of exceedance of the South African National Ambient Air Quality standard of 350 µg/m³ (134ppb), Baseline and Current contour represents area where standard is exceeded more than 88 hours per annum x

12 Figure 5-23 Frequency of exceedance of the South African National Ambient Air Quality standard of 350 µg/m³ (134ppb), Baseline + Phase 1 contour represents area where standard is exceeded more than 88 hours per annum Figure 5-24 Annual average NO 2 concentrations, current power boiler sources only. Contours represent 0.15ppb (blue), 0.32ppb (green), 0.5ppb (magenta) and 0.64ppb (orange) Figure 5-25 Annual average NO 2 concentrations, Mondi Phase 1 sources only. Contours represent 0.15ppb (blue), 0.32ppb (green), 0.5ppb (magenta) and 0.64ppb (orange) Figure 5-26 Annual average NO 2 concentrations, actual 2010 power boiler sources only. Contours represent 0.15ppb (blue), 0.32ppb (green), 0.5ppb (magenta) and 0.64ppb (orange) Figure 5-27 Annual average NO 2 concentrations, baseline and Mondi current. Contours represent 0.53ppb (blue), 1.05ppb (green), 1.6ppb (magenta) and 2.6ppb (orange) Figure 5-28 Annual average NO 2 concentrations, baseline and Mondi Phase 1 sources. Contours represent 0.53ppb (blue), 1.05ppb (green), 1.6ppb (magenta) and 2.6ppb (orange) Figure 5-29 Annual average NO 2 concentrations, baseline and Mondi actual Contours represent 0.53ppb (blue), 1.05ppb (green), 1.6ppb (magenta) and 2.6ppb (orange) Figure 5-30 Highest hourly NO 2 concentrations, current sources only. Contours represent 5.3ppb (blue), 26.3ppb (green), 52.6ppb (magenta) and 106ppb (orange) Figure 5-31 Highest hourly NO 2 concentrations, Mondi Phase 1 sources only. Contours represent 5.3ppb (blue), 26.3ppb (green), 52.6ppb (magenta) and 106ppb (orange) Figure 5-32 Highest hourly NO 2 concentrations, actual 2010 sources only. Contours represent 5.3ppb (blue), 26.3ppb (green), 52.6ppb (magenta) and 106ppb (orange) Figure 5-33 Highest hourly NO 2 concentrations, Mondi current and background sources. Contours represent 26.3ppb (blue), 52.6ppb (green), 78.9ppb (magenta) and 106ppb (orange) Figure 5-34 Highest hourly NO 2 concentrations, Mondi Phase 1 and background sources. Contours represent 26.3ppb (blue), 52.6ppb (green), 78.9ppb (magenta) and 106ppb (orange) Figure 5-35 Highest hourly NO 2 concentrations, Mondi actual 2010 and background sources. Contours represent 26.3ppb (blue), 52.6ppb (green), 78.9ppb (magenta) and 106ppb (orange) Figure 5-36 Expected annual average NO 2 concentrations as a result of phase 1 activities at Mondi xi

13 Figure 5-37 Expected annual average NO 2 concentrations as a result of phase 2 activities at Mondi Figure 5-38 Expected annual average NO 2 concentrations as a result of phase 1 activities at Mondi plus background Figure 5-39 Expected annual average NO 2 concentrations as a result of phase 2 activities at Mondi plus background Figure 5-40 Expected highest hourly NO 2 concentrations as a result of phase 1 activities at Mondi.5-33 Figure 5-41 Expected highest hourly NO 2 concentrations as a result of phase 2 activities at Mondi.5-33 Figure 5-42 Expected highest hourly NO 2 concentrations as a result of phase 1 activities at Mondi plus Richards Bay baseline Figure 5-43 Expected highest hourly NO 2 concentrations as a result of phase 2 activities at Mondi plus Richards Bay baseline Figure 5-44 PM 10 annual average, Mondi current sources only Figure 5-45 PM 10 annual average, Mondi Phase 1 sources only Figure 5-46 PM 10 annual average, Mondi actual 2010 sources only Figure 5-47 PM 10 annual average, Mondi current and background sources Figure 5-48 PM 10 annual average, Mondi Phase 1 and background sources Figure 5-49 PM 10 annual average, Mondi 2010 actual and background sources Figure 5-50 PM 10 highest daily, current sources only Figure 5-51 PM 10 highest daily, Mondi Phase 1 sources only Figure 5-52 PM 10 highest daily, actual 2010 emissions Mondi power boiler sources only Figure 5-53 PM 10 highest daily concentrations, baseline and current PM 10 emissions Figure 5-54 PM10 highest daily concentration, baseline and Phase 1 PM 10 emissions Figure 5-55 Highest daily PM 10 concentrations, baseline and actual 2010 PM 10 emissions Figure 5-56 Frequency of exceedance of the Daily PM standard of 75µg/m, baseline plus current Mondi emissions xii

14 Figure 5-57 Frequency of exceedance of the Daily PM standard of 75µg/m³, baseline plus Phase 1 Mondi emissions xiii

15 Tables Table 3-1 National Ambient Air Quality Standards (DEA 2009) Table 3-2 South African Emission Limits for Solid Fuel combustion installations (DEA 2010) Table 3-3 South African emission Limits for solid biomass combustion installations (DEA 2010) Table 3-4 South African emission Limits for Chlorine Dioxide Plant (DEA 2010) Table 4-1 Long-term minimum, maximum and mean temperature ( C) for Richards Bay for the period (Schulze, 1986), and for (SAWS, 2005) Table 4-2: Long-term average monthly rainfall (SAWS, 2005) Table 4-3: Atmospheric Stability Classes Table 4-4: All industrial sources within the study area and associated air pollutants Table 4-5 Percentage SO 2 data capture for Table 4-6: Comparison of SO 2 annual averages (ppb) for the period (Ecoserv) Table 4-7: Highest SO 2 concentrations (ppb) measured at each station for 2007 to 2010 and percent of standards Table 4-8: Percentage PM 10 data capture and annual average concentrations for Table 4-9 Maximum daily average particulate concentrations for Table 5-1 Emission rates from the boiler stack Table 5-2 Emission concentrations from the boiler stack Table 5-3 Particulate emissions from the material handling operations Phase 1 scenario Table 5-4 Summary of maximum modelled SO 2 Concentrations Table 5-5 Summary of Maximum Modelled NO 2 Concentrations Table 5-6 Summary of Maximum modelled PM 10 concentrations xiv

16 Air Quality Impact Assessment for the Mondi Mill Modification, Richards Bay 1 Introduction Airshed Planning Professionals (Pty) Ltd was appointed by SRK Consulting to undertake an air quality impact assessment for the proposed third steam turbine at the Mondi facility in Richards Bay. The aim of the investigation is to quantify the possible impacts resulting from the increased capacity of steam turbine operation on the surrounding environment and on human health. To achieve this, a good understanding of the regional climate and local dispersion potential of the site is necessary. The primary pollutants of concern are the emissions of sulphur dioxide (SO 2 ) and oxides of nitrogen (NO x ) and particulate matter (PM 10 ) from the steam turbine boiler. Sulphur dioxide is an important criteria pollutant due to its health effects, and is damaging to the human respiratory function (on exposure to bodily fluids sulphuric acid is formed). Exposure to sulphur dioxide concentrations above certain threshold levels increases the prevalence of chronic respiratory disease and the risk of acute respiratory illness. Due to it being highly soluble, sulphur dioxide is more likely to be adsorbed in the upper airways rather than penetrate to the pulmonary region. Nitrogen dioxide (NO 2 ) is a criteria pollutant with implications for human health. Human respiratory tract irritation represents a direct effect of NO x exposures. Due to it being relatively insoluble (relative to sulphur dioxide), NO 2 can penetrate deep into the lungs where tissue damage occurs. Effects of NO 2 exposure include alveolar tissue disruption and obstruction of the respiratory bronchioles. Longterm effects of exposure include increased potentials for lung infections (Koenig, 2000). Particulate matter from fly ash released from the steam boiler is a criteria pollutant. PM 10 (particulate matter less than 10µm in diameter) due to its small size has the ability to penetrate deep into lungs and therefore has important health implications. In addition small quantities of toxic and/or persistent organic compounds and heavy metals are likely to be adsorbed on to the surface of the particulate matter. 1.1 Terms of Reference The terms of reference for this study focused on the air quality impacts of the proposed Mondi Richards Bay power boiler modification including: 1-1

17 Understanding the dispersion potential of the site based on regional meteorological data; Identification and quantification of all sources of air pollution from the steam boiler modification and from the construction of a 500m³ ClO 2 storage facility; Dispersion simulations to determine the impact zones from the modified steam boiler operations; Identification of the main sources of emission and impact and ranking of these sources for the purpose of mitigation measures to be implemented; and Mitigation recommendations and management measures. 1-2

18 1.2 Project Description The Mondi Richards Bay steam boiler modification project is situated in the Mondi Mill facility in the town of Richards Bay in the umhlathuze municipality in the province of KwaZulu-Natal. The objective of project is to identify the changes in atmospheric emissions due to the modification of the current power producing facilities at the plant. The proposed power boiler facility modification will consist of the refurbishment of the two existing coal fired boilers and the installation of a third steam turbine for the production of electricity, provision will be made for one of the boilers to be converted into a biomass boiler in the future, which would use bark and other material unsuitable for pulping from the chipping facility. The modification proposed for this project (which are expected to have been completed by 2015) have the potential of producing a number of positive impacts on the air quality; firstly the refurbishment of the boilers will require the installation of flue gas desulphurisation infrastructure to ensure that the boiler emissions meet the National Emission Standards; secondly it is proposed that there will be the co-generation of steam and electricity, resulting in greater energy efficiency and a reduced reliance on Eskom for electricity supply. If the second phase is undertaken with the conversion of one of the boilers from a coal fuel source to a biomass fuel source it is expected that there will be a potential reduction in the SO 2 emissions (since biomass has a lower sulphur content than coal). This fuel substitution may result in a net reduction in greenhouse gas emissions (Baral and Guha 2004). For the purposes of this project all emission estimates were based on the national emission limits which have the same standard for both coal and biomass fired power generation. The findings are therefore valid for both the fuel types. It must however be noted that the sulphur content of biomass is likely to be much lower than that of coal. It is therefore expected that the ambient SO 2 concentration will be lower when biomass is used. A second section of the project is to determine the impact of installing a 500m³ chlorine dioxide storage facility to provide chlorine dioxide for the bleaching plant when the chlorine generator is out of service. The chlorine dioxide facility will consist of two 250m³ above ground closed tanks. It is not expected that the chlorine dioxide storage tanks would result in any releases on HCl, which is the pollutant of concern with this facility 1.3 Outline of Report This report is divided into eight sections: 1-3

19 Chapter 1 is the introduction which provides the terms of reference a description of the project and an outline of the most important parts of the study. Chapter 2 covers the methodology including a site description, a description of the sensitive receptor points in the region, a description of the emission inventory methodology and requirements, a description of the dispersion model and a list of the assumptions made during this study. Chapter 3 provides an overview of the legislation and guidelines pertaining to air quality in South Africa, including the Air Quality Act, National Ambient Air Quality Standards, and the National Emission Limits. Chapter 4 provides information on the background climate, weather, atmospheric dispersion potential and the background air quality. Chapter 5 covers the air quality impact assessment, including the emissions inventory, the dispersion modelling results Chapter 6 is the summary and conclusions, where the impacts are summarized and the impact discussed. Chapter 7 is a bibliography of the literature consulted for this study Appendix A is an in depth discussion of the methodology, including the emission factors that were used to calculate emissions from various material handling operations. 1-4

20 2 Methodology 2.1 Site Description Richards Bay is a harbour town situated on the KwaZulu-Natal North coast and contains the largest coal terminal in the southern hemisphere. Mondi operates a pulp and paper mill to the west of the port (28 76S and 31 99E) at an altitude of 33m above sea level. 2.2 Sensitive Receptors A number of sensitive receptors occur in the vicinity of the Mondi facility including the industrial area of Alton, located approximately 1km to the east of the plant; the harbour and coal terminal located 5km to the south east of the plant, the residential suburbs of Richards Bay 5km to the east and north east of the Mondi facility, Empangeni 8km to the west and Bhiliya 8km to the south west of the Mondi paper mill. 2.3 Emissions Inventory An emissions inventory was used to identify the most important air pollution sources and to estimate the total emissions from each of these sources. Where possible this was done using information provided by the client. Emissions from this project are expected to be due to two main sources, firstly the emissions from the stack; these were calculated from the emission limits published in the National Environmental Management: Air Quality Act (NEMAQA) (DEA 2004; DEA 2010) for sulphur dioxide (SO 2 ), nitrogen oxides (NO x ) calculated as nitrogen dioxide (NO 2 ) and particulate matter (PM 10 ) from the boilers. Particulate matter emissions from material handling operations were calculated using an emission factor derived from the Australian National Pollution Inventory documentation (NPi 2001). 2.4 Dispersion Model Methodology The use of dispersion modelling by facilities in the Richards Bay area is standardised by the Richards Bay Clean Air Association (RBCAA) to the use of the HAWK model, which is run on-line for all the facilities in the Richards Bay area on a 5 minute time step. For predictive purposes the same model was used to enable a direct comparison between the results. This does have the advantage that all the other major industrial sources in the Richards Bay area are well characterised and therefore the background data is fairly good. Dispersion models compute ambient concentrations as a function of source configurations, emission strengths and meteorological characteristics, thus providing a useful tool to ascertain the spatial and temporal patterns in the ground level concentrations arising from the emissions of various sources. 2-1

21 Increasing reliance has been placed on ground level air pollution concentration estimates from models as the primary basis for environmental and health impact assessments, risk assessments and determining emission control requirements. In the selection of a dispersion model it is important to understand the complexity of the dispersion potential of the area (i.e. the terrain and meteorology), and the potential scale and significance of potential effects (i.e. other sources that might have an influence the ground level concentrations). It was decided to use the HAWK model currently utilised by the RBCAA for dispersion simulations within the study area. The HAWK dispersion model has the ability to simulate unsteady emissions and heavy clouds. The model allows calm, or no-wind conditions, as well as spatially and temporally varying wind fields produced by complex topography. The software package consists of a group of Lagrangian Puff-type models, each applicable to a different dispersion mechanism (e.g. neutral or buoyant normal gases, heavy gases, particles etc.). The choice of dispersion mechanism is done automatically by the code, depending on the factors listed above. The various models in the code were derived from internationally published articles, the accuracy of which is discussed by the respective authors. Input data types required for the HAWK model include: source data, meteorological data, and information on the nature of the receptor grid Source Data Requirements The HAWK model is able to model various source types point (stack/chimney/vent), area, line, volume and fire sources. The source groups included in the model only relate to industrial sources which are modelled as point sources. It is understood that there are a number of other sources in the area, but they have not been quantified in the RBCAA database. All sources require emission rates, coordinates, height above sea level and release height of emissions. In addition, point source parameters include stack height, stack diameter, exit temperature and volumetric flow rate Meteorological Requirements Meteorological parameters that were included in the Hawk model consisted of pressure, wind speed, wind direction, temperature, precipitation, solar radiation, and humidity. Meteorological data for the year 2008 was used for the dispersion simulations using the HAWK model. SGS provided the data on behalf of the RBCAA. 2-2

22 Receptor Grid A grid of 39 km east-west, and 30 km north-south was used to include industries within the umhlathuze and Mbonambi municipalities, with 2043 receptor points over the modelled area Model Accuracy There will always be some error in any geophysical model, but it is desirable to structure the model in such a way to minimise the total error. A model represents the most likely outcome of an ensemble of experimental results. The total uncertainty can be thought of as the sum of three components: the uncertainty due to errors in the model physics; the uncertainty due to data errors; and the uncertainty due to stochastic processes (turbulence) in the atmosphere. The stochastic uncertainty includes all errors or uncertainties in data such as source variability, observed concentrations, and meteorological data. Even if the field instrument accuracy is excellent, there can still be large uncertainties due to unrepresentative placement of the instrument (or taking of a sample for analysis). Model evaluation studies suggest that the data input error term is often a major contributor to total uncertainty. Even in the best tracer studies, the source emissions are known only with an accuracy of ±5%, which translates directly into a minimum error of that magnitude in the model predictions. It is also well known that wind direction errors are the major cause of poor agreement, especially for relatively short-term predictions (minutes to hourly) and long downwind distances. All of the above factors contribute to the inaccuracies not even associated with the mathematical models themselves. Nevertheless, dispersion modelling is generally accepted to be a valuable tool in air quality management practice Dispersion Modelling Results Simulations were undertaken to determine the ground level concentrations from the main pollutants of concern within the study area reflecting current operating conditions. Criteria pollutants included are inhalable particulate matter (PM 10 ) sulphur dioxide (SO 2 ) and nitrogen dioxide (NO 2 ). The predicted exposure periods include highest hourly, daily and annual averages. Dispersion simulations for SO 2 reflect concentration contours for emissions from all major industrial sources within the umhlathuze and Mbonambi areas. The predicted ambient SO 2 concentrations are shown for the hourly, daily and annual averaging periods. Data is presented for the current scenario, the phase 1 scenario and both current and phase 1 with the background modelled SO 2 concentration from all other sources in the Hawk model. Dispersion simulations for NO 2 reflect concentration contours for the annual and hourly averaging periods (no daily average limit values exist for NO 2 ). Data is presented for the current scenario, the phase 1 scenario and both current and phase 1 with the background modelled NO 2 concentration from all other sources in the Hawk model. 2-3

23 The predicted air concentrations of inhalable particles (PM 10 ) are shown as the highest daily and annual average periods for comparison to the respective ambient air concentration limits no hourly average limit values exist- for the current scenario, the phase 1 scenario and both current and phase 1 with the background modelled PM 10 concentration from all other sources in the Hawk model. Particulate matter from the industrial point sources was assumed to be within the PM 10 fraction, as control equipment limiting the emission of larger particles is fitted to the point sources. 2.5 Assumptions In utilizing a dispersion model and emissions inventory such as was done in this project it is necessary to make a number of assumptions, the most important of which relate to the inherent accuracy of the dispersion model that is used, the assumptions made during the emission calculations and the meteorology that is used. These assumptions include: Routine emissions were estimated and modelled. Atmospheric releases occurring as a result of accidents were not accounted for. A minimum of 1 year, and typically 3 to 5 years of meteorological data are generally recommended for use in atmospheric dispersion modelling for air quality impact assessment purposes. One year of meteorological data was analysed (2008), due to the extended running time of the HAWK model. The year 2008 was chosen since the Richards Bay background has been modelled for this year and it therefore provides an opportunity to compare the modified Mondi impacts against the background ambient air quality at Richards Bay. A comparison was made with the wind roses for and temperature profiles for the years 2009 and 2010 and these years show similar wind fields and meteorological conditions. We therefore feel confident that the meteorology for 2008 is representative of the conditions that occur in Richards Bay (see Figure 4-3, Figure 4-4 and Figure 4-5). Power boiler emission estimates were limited to include SO 2, NO x and PM 10., While other emissions are known to occur they were not modelled in this study. Operations were assumed to be twenty-four hours over a 365 day year as a conservative approach. 2-4

24 3 Legislative Overview of Air Quality Standards Prior to assessing the impact of the proposed modification steam boilers at the Mondi Richards Bay site, reference needs be made to the environmental regulations and guidelines governing the emissions and impact of such operations. Air quality guidelines and standards are fundamental to effective air quality management, providing the link between the source of atmospheric emissions and the user of that air at the downstream receptor site. The ambient air quality guideline values indicate safe daily exposure levels for the majority of the population, including the very young and the elderly, throughout an individual's lifetime. Air quality guidelines and standards are normally given for specific averaging periods. These averaging periods refer to the time-span over which the air concentration of the pollutant was monitored at a location. Generally, five averaging periods are applicable, namely an instantaneous peak, 1-hour average, 24-hour average, 1-month average, and annual average. The application of these standards varies, with some countries allowing a certain number of exceedances of each of the standards per year. 3.1 South African Legal Requirements According to the Air Quality Act No.39 of 2004 Under the (now defunct) Atmospheric Pollution Prevention Act (Act No 45 of 1965) (APPA) the focus was mainly on source-based controls with Registration Certificates issued for Scheduled Processes. Scheduled processes, referred to in the Act, are processes which emit more than a defined quantity of pollutants per year, including combustion sources and smelting. Best Practicable Means (BPM), on which the Registration Certificate requirements are based, represents an attempt to restrict emissions while having regard to local conditions, the prevailing extent of technical knowledge, the available control options, and the cost of abatement. The Department of Environmental Affairs (DEA) was responsible for the administration of this Act with the implementation thereof charged to the Chief Air Pollution Control Officer (CAPCO). Although emission limits and ambient concentration guidelines were published by DEA, no provision was made under the APPA to publish formal ambient air quality standards or emission standards. The decision as to what constituted the best practicable means for each individual case was reached following discussions with the industry. A registration certificate, containing maximum emission limits specific to the industry, was then issued. The APPA was outdated and not in line with international best practice. It also proved inadequate to facilitate the implementation of the principles underpinning the National Environmental Management 3-1

25 Act (NEMA) and the Integrated Pollution and Waste Management (IP&WM) white paper. In this light, the National Environmental Management: Air Quality Act (Act no. 39 of 2004) was drafted, shifting the approach from source based control to decentralised air quality management through an effectsbased approach. The new National Environmental Management: Air Quality Act (DEA 2004) has shifted the approach of air quality management from source-based control only to the reduction of impact on the receiving environment. The Act has also placed the responsibility of air quality management on the local authorities (district and metropolitan municipalities) who are tasked with baseline characterisation, management and operation of ambient monitoring networks, licensing of listed activities, and emissions reduction strategies. The main objective of the act is to ensure the protection of the environment and human health through reasonable measures of air pollution control within the sustainable (economic, social and ecological) development framework. 3.2 National Ambient Air Quality Standards The Air Quality Act (AQA) makes provision for the setting of ambient air quality standards and emission limits at national level, which provides the objective for air quality management. More stringent ambient standards may be implemented by provincial and metropolitan authorities. National ambient standards were published on 24 Dec 2009 (GG 32816) as per Table 3-1 (DEA 2009). 3-2

26 Table 3-1 National Ambient Air Quality Standards (DEA 2009) Averaging Period Concentration Allowed Frequency of Exceedence Compliance Date Sulphur Dioxide (SO 2) 10 minutes 500µg/m³ (191ppb) 526 Immediate 1 hour 350µg/m³ (134ppb) 88 Immediate 24 hours 125µg/m³(48ppb) 4 Immediate 1 year 50µg/m³ (19ppb) 0 Immediate Nitrogen Dioxide (NO 2) 1 hour 200µg/m³ (106ppb) 88 Immediate 1 year 40µg/m³ (21ppb) 0 Immediate Particulate Matter (PM 10) 24 hours 120µg/m³ 4 Immediate- End 24 hours 75µg/m³ 4 1 January year 50µg/m³ 0 Immediate-End 1 year 40µg/m³ 0 1 January Ozone (O 3) 8 hours (running) 120µg/m³ (61ppb) 11 Immediate Benzene (C 6H 6) 1 year 10µg/m³ (3.2ppb) 0 Immediate-end year 5µg/m³ (1.6ppb) 0 1 January 2015 Lead (Pb) 1 year 0.5µg/m³ 0 Immediate Carbon Monoxide (CO) 3-3

27 Averaging Period Concentration Allowed Frequency of Exceedence Compliance Date 1 hour 30mg/m³ (26ppm) 88 Immediate 8 hour (calculated from 1 10 mg/m³ (8.7ppm) 11 Immediate hour averages) 3.3 Listed Activities which may result in Air pollution Listed activities were identified by the Minister and include all activities regarded to have a significant detrimental effect on the environment, including health. Emission limits are established at national level for each of these activities (DEA 2010) and an atmospheric emission licence will be required in order to operate. With the decentralisation of power to provincial and local authority level, district and metropolitan municipalities will be responsible for the issuing of licences for listed activities. An air quality officer appointed by local authorities and responsible for the issuing of atmospheric emission licences may require a company or person to submit atmospheric impact reports in order to determine the impact of the proposed emissions on ambient air quality. The proposed modification of the coal fired steam boilers falls under subcategory 1-1 of the regulations and must meet emission standards as given in Table 3-2 below. During phase 2 when one of the boilers is to be converted to operate on solid biomass the emission standards fall under subcategory 1.3: Solid biomass combustion installations. The installation of a chlorine dioxide storage facility may trigger listed activity Subcategory 9.4 relating to chlorine dioxide plants as given in Table 3-4 although the legislation refers to the production and use, rather than the storage of ClO 2. Table 3-2 South African Emission Limits for Solid Fuel combustion installations (DEA 2010) Description Solid fuels (excluding biomass) combustion installations used primarily used for steam raising or electricity generation Application All installations with design capacity equal to or greater than 50MW heat input per unit, based on the lower calorific value of the fuel used Substance or mixture of substances Plant Mg/Nm 3 under normal conditions of 10% Common Name Chemical symbol Status O 2, 273 Kelvin and kpa Particulate matter N/A New 50 Existing 100 Sulphur Dioxide SO 2 New 500 Existing 3500 Oxides of nitrogen NO x expressed as New 750 NO 2 Existing

28 Table 3-3 South African emission Limits for solid biomass combustion installations (DEA 2010) Description Solid biomass fuel combustion installations used primarily used for steam raising or electricity generation Application All installations with design capacity equal to or greater than 50MW heat input per unit, based on the lower calorific value of the fuel used Substance or mixture of substances Plant Mg/Nm 3 under normal conditions of 10% Common Name Chemical symbol Status O 2, 273 Kelvin and kpa Particulate matter N/A New 50 Existing 100 Sulphur Dioxide SO 2 New 500 Existing 3500 Oxides of nitrogen NO x expressed as New 750 NO 2 Existing 1100 Table 3-4 South African emission Limits for Chlorine Dioxide Plant (DEA 2010) Description Production and use of chlorine dioxide for paper production Application All installations Substance or mixture of substances mg/nm³ under normal Common Name Chemical Symbol Plant Status conditions of 273 Kelvin and kpa Hydrogen Chloride HCl New 15 Existing

29 4 BASELINE CHARACTERISATION 4.1 Meteorological conditions Meteorological characteristics of a site govern the dispersion, transformation and eventual removal of pollutants from the atmosphere (Pasquill and Smith 1983; Godish 1990). In the assessment of the possible impacts from air pollutants on the surrounding environment and human health, a good understanding of the regional climate and local air dispersion potential of a site is essential. Meteorological mechanisms govern the dispersion, transformation, and eventual removal of pollutants from the atmosphere. The extent to which pollution will accumulate or disperse in the atmosphere is dependent on the degree of thermal and mechanical turbulence within the earth s boundary layer. Dispersion comprises vertical and horizontal components of motion. The vertical component is defined by the stability of the atmosphere and the depth of the surface mixing layer. The horizontal dispersion of pollution in the boundary layer is primarily a function of the wind field. The wind speed determines both the distance of downwind transport and the rate of dilution as a result of plume stretching. The generation of mechanical turbulence is similarly a function of the wind speed, in combination with the surface roughness. The wind direction and the variability in wind direction, determine the general path pollutants will follow, and the extent of cross-wind spreading (Shaw and Munn 1971; Pasquill and Smith 1983; Oke 1990).The analysis of hourly average meteorological data is necessary to facilitate a comprehensive understanding of the ventilation potential of the site. The vertical dispersion of pollution is largely a function of the wind field. The wind speed determines both the distance of downward transport and the rate of dilution of pollutants. The generation of mechanical turbulence is similarly a function of the wind speed, in combination with the surface roughness. Air temperature is an important parameter for the development of the mixing and inversion layers. It also determines the effect of plume buoyancy as the larger the temperature difference between ambient air and the plume, the higher the plume will rise. This in turn will affect the rate of dissipation of pollutants before it reaches ground level. Incoming solar radiation also determines the rate of development and dissipation of the mixing layer. Relative humidity is an inverse function of ambient air temperature, increasing as ambient air temperature decreases. Precipitation represents an effective removal mechanism of atmospheric pollutants and is therefore frequently considered during air pollution studies. Evaporation is a function of ambient temperature, wind and the saturation deficit of the air. Evaporation rates have important implications for the design and implementation of effective dust control programmes. Pollution concentration levels fluctuate in response to changes in atmospheric stability, to concurrent variations in the mixing depth, and to shifts in the wind field. Spatial variations, and diurnal and 4-1