2. Research Methodology
2.1 Preliminary Literature Review
A preliminary literature review of recent journals, conference papers, theses, government reports, newspapers and periodicals was carried out by Nerac Incorporated (Nerac) on behalf of MWH. Nerac performed two keyword searches. The first search on "use or disposal of old used tires (sic.)" provided 17 references and the second on "storage of old used tires (sic.)" provided 10 references. The majority of the references were not related directly to storage. The low number of references returned suggests there is little published research material related directly to tyre storage.
2.2 Review of Technical Guidelines on the Identification and Management of Used Tyres
This document, produced by the Technical Working Group of the Basel Convention in 1999, provided the starting point for the research. It provided a description of tyre properties, an overview of potential environmental risks of tyre storage, an outline of various reprocessing options for used tyres and a description of landfilling and stockpiling used tyres. This document was poorly referenced to source material; however references were followed up when given.
2.3 Preliminary Outline for Guideline on Management of End-of-life Tyres
A preliminary outline structure of a best practice guideline for the management of end-of-life tyres was prepared by MWH and is presented in Appendix C. This guideline set the context for the investigation to ensure the research was focused on the output required by the Ministry.
2.4 Review of Previous MWH Work
MWH has had limited experience in the area of tyre storage. Research was carried out in 2003 on the development of a regional waste recovery/processing sector in the Wellington region. [MWH New Zealand Ltd (June 2003)"Development of a Regional Waste Recovery / Processing Sector". A report prepared for the Wellington City Council, Ministry for the Environment and Ministry of Economic Development.] The research included reprocessing technologies for end-of-life tyres but did not include tyre storage.
2.5 Review of Recent Literature from Waste Management Organisations
Recent literature was reviewed from international waste management organisations, including:
- United States Environmental Protection Association, USEPA, United States
- Rubber Manufacturers Association, RMA, United States
- Clear Washington Council, CWC, United States
- Used Tyre Working Group, United Kingdom
- United Kingdom Environmental Agency, UKEA, United Kingdom
- Oregon Department of Environmental Quality, DEQ, United States
- National Research Council Canada, NRC, Canada
- California Integrated Waste Management Board, CIWMB, United States
- National Fire Protection Association, NFPA, United States
- International Association of Fire Chiefs, IAFC, United States
- Scrap Tyre Management Council, STMC, United States
- Ministry of Waste, Land and Air Protection, Canada
- South Australian Environmental Protection Agency, Australia
- EcoFlex, Australia.
2.6 Key Word Web Search
Several key word searches were also done using the search engine "Google". Key words used in various searches included: scrap tires, used tyres, storage, monofill, best practice, guidelines, and leachate. References obtained through these searches were reviewed.
2.7 International Experts and Practitioners
Contact was established with a variety of national and international experts and practitioners in the hazardous waste field. Communications were made by telephone, e-mail or by using MWH's Intranet system known as Knet. In many cases these experts admitted to little direct knowledge of the specific area of end-of-life tyre storage and disposal, perhaps indicating just how specialised this issue is.
However Owen Douglas, a contact provided by Ministry for the Environment, was able to provide MWH with a copy of the Scrap Tire and Rubber Users Directory, 2003 Edition. It contains many contacts throughout the world. The directory was received too late to be used in this investigation; however it would be a useful resource for the Ministry in further investigations on end-of-life tyres.
Owen Douglas also provided contact details for Michael Playton, who has 20 years' experience in the tyre reprocessing industry and is currently the International Sales Manager for Columbus McKinnon, manufacturers of tyre shredding machines. Mr Playton has experience with tyre storage throughout the world, including Asia and the United States, and provided information for this report.
2.8 Reference List
During this investigation a list of relevant references and websites was compiled. This list is presented in Appendix A.
