Investigation of the Composition and Emissions of Trace Components in Landfill Gas R&D Technical Report P1-438/TR T. Parker, J. Dottridge, and S. Kelly Research Contractor: Komex . Publishing Organisation Environment Agency, Rio House, Waterside Drive, Aztec West, Almondsbury, BRISTOL, BS32 4UD Tel: 01454 624400 Fax: 01454 624409 Website: www.environment-agency.gov.uk Environment Agency 2002 ISBN: 1 84432 018 9 All rights reserved. No parts of this document may be reproduced, stored in a retrieval system, or transmitted, in any form or by any other means, electronic, mechanical, photocopying, recording or otherwise without the prior permission of the Environment Agency. The views expressed in this document are not necessarily those of the Environment Agency. Its officers, servants or agents accept no liability whatsoever for any loss or damage arising from the interpretation or use of the information, or reliance on views contained herein. Dissemination Status Internal: Released to Regions External: Public Domain Statement of Use This research & development report is one of a series relating to the management of landfill gas. It underpins work to develop guidance for measuring the composition and concentraion of trace components in landfill gas at permitted or licensed landfill sites in England and Wales. Further research in being undertaken as part of R&D Project P1- 491 ‘Quantification of trace comonents in landfill gas’. Keywords Trace components, landfill gas, monitoring, emissions, health effects, odour, prioritisation. Research Contractor This document was produced under R&D Project P1-438 by: Komex, 129 Cumberland Road, Bristol, BS1 6UY Tel: 0117 925 1304 web: www.komex.com Komex were supported by G. Apps, and J. Cox of Harwell Scientifics for analytical techniques. Environment Agency Project Manager The Environment Agency’s Project Manager for R&D Project P1-438 was: Alan Rosevear, Thames Region. CONTENTS Abbreviations Executive Summary 1 INTRODUCTION 1 1.1 Background to the project 1 1.2 Objectives 1 1.3 Report contents 1 1.4 Issues associated with trace components in landfill gas 2 1.5 Potential sources of trace components 2 2 PUBLISHED DATA 5 2.1 UK research until 1988 5 2.1.1 Trace component data 5 2.1.2 Trace component odour data 7 2.2 Post-1988 UK research 8 2.2.1 Trace component data 8 2.2.2 Trace component odour data 9 2.2.3 Monitoring methods 9 2.2.4 Treatment prior to use in landfill gas engines 9 2.2.5 Landfill gas migration in the subsurface 10 2.2.6 Human health and ecological risk assessment 10 2.2.7 Leachate and landfill gas 11 2.3 European research 11 2.3.1 Landfill gas data 11 2.3.2 Trace component odour data 12 2.3.3 On-site health impacts 12 2.3.4 Leachate and landfill gas 12 2.4 North American research 12 2.4.1 Landfill gas data 13 2.4.2 Trace component odour data 14 2.4.3 Ambient air concentrations 15 2.4.4 Particulate emissions 15 2.4.5 Human health 16 2.4.6 Monitoring methods 16 2.4.7 Emissions 17 2.5 Japanese research 19 3 RELEVANCE OF PUBLISHED DATA 21 4 ASSESSING VALUES OF PUBLISHED DATA 23 4.1 Data Assessment 23 4.1.1 Type of waste 23 4.1.2 Age of waste/Stage of waste degradation 27 4.1.3 Analytical methods used 27 4.1.4 Moisture content of landfill 28 4.1.5 Site location 28 4.2 Data quality matrix 29 5 SITE SPECIFIC STUDY 31 R&D TECHNICAL REPORT P1-438/TR i 6 DATABASE 33 6.1 Data sources 33 6.1.1 Operator data 33 6.1.2 Research data 33 6.2 Database structure 33 6.3 Development 34 6.4 Database data worth 35 6.4.1 Type of waste 35 6.4.2 Age of waste/Stage of waste degradation 36 6.4.3 Analytical methods 36 6.4.4 Moisture content of landfill 37 6.4.5 Site location 37 6.5 Data quality matrix 37 6.6 Repository of data 37 7 POTENTIAL TOXICITY IMPORTANCE MATRIX 39 7.1 Rationale 39 7.2 Toxicity ranking methodology 40 7.2.1 Reference concentration rating 40 7.2.2 Safety factor ranking 42 7.3 Physical property ranking methodology 43 7.4 Results 45 8 POTENTIAL ODOUR IMPORTANCE MATRIX 47 8.1 Rationale 47 8.2 Odour ranking methodology 47 8.3 Results 48 9 TRACE COMPONENT CONCENTRATIONS 49 9.1 Use of median versus average concentrations 50 9.2 Amount of data 52 9.3 Chemical group results 523 10 TRACE COMPONENT PRIORITISATION 55 10.1 Prioritising components with a potential for health impact 55 10.2 Prioritising components with a potential for odour impact 57 10.3 Sensitivity analysis 58 10.4 Detection limits 61 10.5 Omission analysis 62 11 POTENTIAL SYNERGY 63 11.1 Other effects 63 12 METHODS TO MONITOR EMISSIONS OF PRIORITY COMPONENTS 65 12.1 Real time analysis 65 12.2 Laboratory methods 66 12.3 VOC sample collection 67 12.3.1 Tedlar bag sampling 67 12.3.2 Summa canister 68 12.3.3 Thermal desorption tube 68 12.4 Methanal sampling and analysis 69 12.5 Hydrogen sulphide sampling and analysis 70 12.6 Metals sampling and analysis 70 12.6.1 Arsenic 70 12.6.2 Mercury 71 R&D TECHNICAL REPORT P1-438/TR ii 12.7 Summary of analytical methods selection 71 12.8 New developments 72 13 TREATMENT METHODS TO REDUCE EMISSIONS 75 13.1 Reduction/Control 75 13.2 Pre-treatment 76 13.2.1 Water removal 77 13.2.2 Particulate removal 77 13.2.3 Pre-treatment emission reduction 78 13.3 Secondary treatment 78 13.3.1 Wet scrubbing 78 13.3.2 Dry scrubbing 79 13.3.3 Membranes 79 13.3.4 Pressure swing processes 80 13.3.5 Cryogenics 80 13.4 Combustion/Energy utilisation 80 13.4.1 Flares 81 13.4.2 Boilers 82 13.4.3 Internal combustion engines 82 13.4.4 Gas turbines 82 13.4.5 Fuel cells 82 13.4.6 Emissions from combustion technology 83 13.4.7 Post combustion/energy utilisation 83 13.5 Other uses of landfill gas 84 13.5.1 Methanol production 84 13.5.2 Cleaning to natural gas pipeline specifications 84 14 CONCLUSIONS 85 14.1 Review of published data 85 14.2 A database of published information, grey data & site specific data 85 14.3 Ranking the inherent toxicological and odour importance 86 14.4 Ranking significance of trace gases reported in UK landfill gas 87 14.5 Monitoring methods 88 14.6 Emission reduction 89 15 REFERENCES 91 APPENDICES APPENDIX I Site specific sampling data APPENDIX II Identified trace components of landfill gas APPENDIX III Assessment tables (Contained as spreadsheets on enclosed CD) TABLE 1 Toxicity Ranking Data TABLE 2 Mobility Ranking Data TABLE 3 Toxicity Significance Matrix TABLE 4 Odour Ranking Data TABLE 5 Odour Significance Matrix TABLE 6 Toxicity Significance Ranking TABLE 7 Odour Significance Ranking TABLE 8 Emission Reduction Technology R&D TECHNICAL REPORT P1-438/TR iii ABBREVIATIONS AAS Atomic Adsorption Spectroscopy AFS Atomic Fluorescence Spectrometry ASTM American Society for Testing and Materials ATD Automated Thermal Desorption tube CCR California Code of Regulations (CCR); CEQA California Environmental Quality Act CFR Code of Federal Regulations CIWMB California Integrated Waste Management Board CO Carbon Monoxide EAS Emission Atomic Spectroscopy GC Gas Chromatography HAPs Hazardous Air Pollutants HCl Hydrochloric Acid HDPE High-Density Polyethylene HPLC High Pressure Liquid Chromatography IC Ion Chromatography ICP Inductively Coupled Plasma MDHS Methods for the Determination of Hazardous Substances MS Mass Spectroscopy MSWL Municipal Solid Waste Landfill NIOSH National Institute of Occupational Health and Safety NMOC Non-Methane Organic Compounds OSHA Occupational Safety and Health Organisation PAH Polycyclic Aromatic Hydrocarbon PM Particulate Matter PVC Polyvinyl Chloride RCRA Resource Conservation and Recovery SCAQMD South Coast Air Quality Monitoring District SOx Oxides of Sulphur TAC Toxic Air Contaminant TOC Threshold Odour Concentration USEPA United States Environmental Protection Agency VOC Volatile Organic Compounds R&D TECHNICAL REPORT P1-438/TR iv EXECUTIVE SUMMARY This project addresses the source term for trace components that are emitted with the bulk gases from UK landfills. Comprehensive sampling of gas at one landfill site has augmented published and unpublished data on gaseous trace components. These data have been input into a database of information on trace components in UK landfill gas. Published toxicological and odour properties of trace components identified in landfill gas have been used to rank the potential impact of substances listed in the database. This ranking has been scaled against the average concentration of the substances reported in the database to estimate the potential contribution of each substance to the toxicological and odour impact of landfill gas. Analytical methods capable of measuring the substances ranked high in these priority lists have been identified and evaluated and methods that might reduce the emissions of these priority substances reviewed. Review of existing data The review of publicly available data on trace components of landfill gas concluded that most of the published UK data had been gathered at ‘problem’ sites likely to generate gas with relatively high concentrations of a wide range of trace components. This subsequently skewed the available dataset towards worst case conditions. It was also concluded that previous research had concentrated on discrete aspects, such as odourous components, rather than looking at the full spectrum of trace components in a particular sample and their overall impact. A database of published, unpublished and new information Trace component concentrations and associated ‘metadata’ from published reports have been entered into a database.