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Publications archive - Hazardous waste


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Hazardous Waste Technical Group - 58th meeting

Friday 22 November 2002
Pasminco Cockle Creek Smelter
Main Road, BOOLAROO NSW 2284

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Professor Paul Greenfield


Dr Paul Brown
Dr Peter Nadebaum
Dr Peter Di Marco
Dr Peter Scaife
Mr John Hogan
Dr Neill Stacey
Mr Stephen Moore


Dr Peter Brotherton


Mr Robert Angel
Dr Geoff Thompson
Dr Greg Rippon


Dr Robyn Eckersley
Dr Jenny Stauber
Ms Diane Kovacs

Agenda Item 1. Draft Minutes of the 57th meeting

1. The meeting amended paragraphs 8, 15 and 19 and deleted paragraph 10. As amended, the draft Minutes were adopted.

Agenda Item 2. Matters arising

2. There were no matters arising.

Agenda Item 3. Progress report on operation of the Hazardous Waste Act

(a) Permit report for previous twelve months

3. The meeting noted the agenda paper.

Agenda Item 4. Technical issues arising from applications and inquiries

(a) Proposed export of spent potlinings

4. The meeting noted from the agenda paper that the NSW Environment Protection Authority was not in favour of temporary storage of hazardous waste in shipping containers while the export option was available. Tomago had provided a timeline for constructing a new storage building on site indicating that, from the decision to proceed to handover, design and construction would extend over a period of ten months. Regain Services Pty Ltd had written to Tomago to ensure that Tomago was properly informed about the work that Regain was doing, and to support the current application for an export permit. The Department of the Environment and Heritage had asked Tomago to justify the quantity of 10,200 tonnes to be shipped, and why a lesser amount would not be sufficient. Tomago had replied that 10,200 tonnes was the minimum that needed to be shipped and that Tomago's occupational health and safety officials had questioned whether enough SPL would be removed to create a safe working environment. If not, it might be necessary to consider applying for a second shipment.

5. The meeting agreed that a single shipment of 10,200 tonnes should be permitted. It was important that Tomago continue to actively assist Regain with their work, and no future export applications were anticipated.

(b) Possible import of POPs wastes

6. There was no report under this standing item.

(c) Possible import of Flue-gas Desulphurisation Gypsum to rehabilitate land

7. The secretariat had yet to finalise its letter to Professor Rudolph.

(d) Proposed export of used lead-acid batteries to New Zealand

8. The Technical Group noted the agenda paper, which described the relationship between Australia's obligations under the Basel Convention and its obligations under two economic conventions, the WTO Agreement (particularly the GATT) and the Australia New Zealand Closer Economic Relations Agreement (CER). Under both economic conventions, Australia has obligations not to impose export restrictions other than through duties, taxes or other charges. However, both conventions provide for exceptions to this obligation under certain circumstances. If Australia were to refuse an export permit, consideration would need to be given to whether such an action would be prima facie consistent with the exceptions outlined in Article XX of the GATT and Article 18 of CER.

9. The reason for refusing to grant a permit would be to meet the obligation under Article 4.2(d) of the Basel Convention, to reduce transfrontier movements to the minimum consistent with the environmentally sound and efficient management of the waste. The problem is that the refusal to issue a permit would result in Exide's New Zealand smelter losing half its feedstock. If this led ultimately to closure of the smelter and it became necessary to export ULABs from New Zealand, transboundary movements might continue at the same, or even an increased, level, but in the opposite direction. In this event, refusing the permit would not have been necessary to achieve the environmental objective contained in Article 4.2(d) of the Basel Convention, the exceptions provisions in the GATT and CER would not apply, and Australia could have been in breach of its GATT and CER obligations as well as its Basel Convention obligation.

(e) Proposed import of used lead-acid batteries from New Zealand

10. The chair noted that at the previous meeting, the Group had advised that this permit should be refused.

(f) Red water sample export determination

11. Red water is generated during the final aqueous stage of trinitrotoluene (TNT) production. TNT, which is heavier than water, was separated out as a stable product, leaving dissolved by-products in the aqueous residual, that is, red water. As an aqueous material, red water is stable but is regulated due to its toxic characteristics. TNT is not currently produced in the USA and it was proposed to export two 400-kilogram samples for experimental treatment by supercritical water oxidation, which destroys organic materials using an oxidant in water at temperatures and pressures above the critical points of water, that is 374 C and 218 atm. The object was to demonstrate that the sample material could be rendered non-hazardous and completely oxidised into carbon dioxide, water and common salts.

12. The Department of the Environment and Heritage had been unable to identify the red water with any of the waste categories listed in Annex I of the Basel Convention. Category Y15 covers wastes of an explosive nature, and the red water contains traces of TNT and other explosive nitrated aromatics, but the 75-85% water content nullifies any explosive potential of this waste. The information provided indicated that the water contained no other Basel Annex I constituents at levels likely to exhibit Annex III hazardous characteristics.

13. The meeting agreed that supercritical water oxidation should be an effective method for decomposition of organic contaminants in water, but it was expensive. A member expressed concern that hazardous wastes could be exported with a permit if they were not listed in Annex I of the Convention.

(g) Possible export of Chemcollect wastes.

14. The meeting noted that various technologies were capable of destroying these wastes, but only one facility was currently operating commercially in Australia. This had a limited capacity and could not handle some contaminated materials. For example, there were problems with possible cross-contamination by arsenic and mercury. It was possible that some applications would be made for export permits for the more difficult wastes.

15. If NSW approved the Geomelt process for the hexachlorobenze wastes currently at Port Botany, it would then go through a seven-stage process that would have been rigorously trialled. It would not have been trialled on the Chemcollect materials, but the technology had real capabilities. At the moment, however, there was insufficient basic information on the wastes being stored and the secretariat was asked to approach the States and Territories to obtain data on types and quantities.

Agenda item 5. Reports of international meetings

16. There was no discussion of this item.

Agenda Item 6. Work Program of the Technical Group

17. There was no discussion of this item.

Agenda Item 7. Criteria for separating hazardous from non-hazardous wastes

(a) Australian submission on the hazard status of ozone-depleting substances.

18. The meeting commented that the use of dictionary definitions was very self-defeating. The argument that ozone-depleting substances impacted the environment by means of toxic effects was drawing a very long bow. Even carbon dioxide would be hazardous under such a definition. Ozone-depleting substances were being managed under the Montreal Protocol and were not core business for the Basel Convention.

(b) Hazard status of PVC

19. There was no discussion of this item.

(c) Hazard status of zinc ash

(i). The hazard status of zinc secondary materials originating from hot dip galvanising processes

(ii). Draft evidentiary certificates for zinc ash and zinc granules

20. Hot dip galvanizing is a batch process where iron and steel articles to be coated with zinc are immersed in an electrically heated steel bath (or kettle) of molten zinc and then removed from the bath, where the zinc solidifies forming a tightly adhering casing to the steel work pieces. It is usual for the zinc bath to contain a small amount of lead (typically 1-1.5%). There are a number of reasons why the lead is beneficial, and these include improved appearance of the final zinc coat (a property known as spangle), and protection for the steel bath against "burn out" as the molten zinc attacks the steel, The lead drops to the bottom of the bath and helps even distribution of heat - thus avoiding "hot spots" where the attack on the steel by the molten zinc is exacerbated

21. The molten zinc at the top of the bath is in contact with air, and some zinc reacts to form zinc oxide. This becomes entrained in molten metal, and as the bath continues in use a crust of mixed ZnO/Zn builds up on the surface. This is known as galvanisers' ash, zinc ash or zinc skimmings, and typically contains 55% zinc metal and 45% zinc oxide, with the overall zinc content around 80-85%. The ash also contains around 1 to 1.5% lead and 0.5% iron.

22. Due to the lead content and the high content of fine particulate (dispersible) material, there is no question that the zinc ash is a hazardous waste. However, the material under consideration was zinc ash that had been fed into an "autogenous mill" which had a similar function to a conventional ball mill, except that particle attrition was achieved through impact of particles of the charge with each other, rather than through impacts between the charge and steel balls. This general process is also known as "Self Attrition Grinding" or SAG.

23. The mill operated under a partial vacuum (or air sweep) and fine particles were continuously removed in the air stream and recovered in a bag house. All of the oxide material was abraded from the surface of the metallic particles, ground to very fine size and removed in the air sweep. Fine metallic particles are also removed in the air stream leaving relatively large metallic particles, which are removed at the discharge end of the machine. The problem before the meeting was how to distinguish smaller particles that were waste zinc residues containing lead, a hazardous waste, and larger particles that were zinc scrap in metallic, non-dispersible form, a non-hazardous waste.

24. Members discussed the difficulty of defining an essentially subjective expression like "non-dispersible". So far as human health was concerned, members agreed that particles with high specific gravity whose diameter was larger than 100 microns would not present a respiratory hazard. Setting a particle size to protect the environment was more difficult. For example, did non-dispersible mean that spilt material could be picked up and put on a truck? One way to approach the problem was to refer to the procedures for leachate tests, which provide a measure of a whether a material is likely to leach chemicals into the environment. The Australian Standard for preparation of leachate requires that particles shall be reduced if necessary to pass through 2.4 mm aperture sieve and this could be used to distinguish the larger particles from the smaller ones.

25. After further discussion, the meeting agreed that zinc scrap in metallic, non dispersible form includes material that is retained on a sieve of 1 mm aperture size. This size is a pragmatic compromise between 100 microns, a conservative limit for respirable dust, and 2.4 mm, the size to which particles must be reduced in the Australian Standard for preparation of leachate. Because leachates are prepared to assess the potential for contamination of groundwater, the latter size was regarded as a surrogate for dispersibility into the environment. The meeting further decided that 99 percent of the material should be retained on the sieve, and asked the Secretariat to use appropriate language from the Australian Standard for Test sieving procedures.

(iii). EA Information Circular for Customs No. 2002/01

26. The meeting noted the EA Circular for Customs No. 2002/01.

(iv). Hazard status of zinc and copper ash, dross and residues under the Hazardous Waste Act. Guidance Paper, April 2001

27. There was no discussion of this item.

Agenda Item 8. Criteria for separating wastes from non-wastes

Agenda Item 9. Defining environmentally sound management

Agenda Item 10. Regional Centres

28. There was no discussion of these items.

Agenda Item 11. Avoidance, minimisation and treatment of hazardous wastes

(a) Environment Protection and Heritage Council: National Environment Ministers act on air quality and waste management

29. The meeting noted the Ministers were taking a broader view of chemicals in the Chemicals Working Group and this was very encouraging.

Agenda Item 12. Other Business

30. There was no discussion of these items.

Agenda Item 13. Dates of next meetings

(b) Friday 7 February 2003, Port Kembla

(c) Friday 7 March 2003, Melbourne