CMPS&F - Environment Australia
Appropriate technologies for the treatment of scheduled wastes
Review Report Number 4 - November 1997
A Ball Milling process for the treatment of chlorinated wastes is being developed by the University of Western Australia (McCormick, 1994 and Donecker, 1994). CRA-ATD was involved in the earlier stages of process development but have since withdrawn their support. The process uses a mineral processing ball mill to effect treatment of the waste material.
The Ball Milling process is a mechano/chemical process, relying on the energy released at the point of collision between balls in a ball mill to activate a reaction between the waste and CaO (lime), breaking down the organochlorine compounds. By-products of the destruction of organochlorine compounds using CaO are generally of low toxicity and may include graphite, calcium chloride and calcium hydroxide. Details of system performance were still unavailable for this review. However, the treated materials are expected to be suitable for disposal to landfill in the case of solid wastes, or other normal disposal methods in the case of liquid wastes (McCormick, 1996).
The process may be applied to concentrated forms of halogenated hydrocarbons such as PCBs and DDT. In the case of contaminated electrical components, the possibility exists to destroy the encapsulating container in the same process. Disperse wastes (eg contaminated soil) would preferably be concentrated by solvent extraction or a similar process prior to destruction within the ball mill treatment system.
While still very much at an experimental stage, the ball milling process has a number of potential advantages:
No information on the costs of the process and operating requirements such as energy usage are available as the process is still in the experimental stage. The proponents suggest that costs are likely to be competitive with other scheduled waste treatment systems that are able to treat a range of wastes.
The technology is currently demonstrated only at laboratory scale. Development is continuing, but no time scale for commercialisation is set. Tests undertaken to date have been on concentrated materials.
(a) Proponents (In Australia)
University of Western Australia.
(b) Wastes Applicable
Ball Milling is likely to be able to treat most waste types including PCB contaminated electrical equipment. It is most effectively applied to concentrated wastes.
(c) Contaminants Applicable
This process is likely to be able to treat all scheduled compounds, although testing to date is limited.
The process remains at laboratory scale with further research and development work continuing.
(e) Timing for Commercialisation in Australia
Expected to be greater than 5 years but the time frame is uncertain.
(f) Cost (example only)
Unknown, proponents suggest the cost of this process will be competitive with incineration.
(g) Safety/Environmental Risk
There is a low potential for release of waste and no gaseous emissions. Dioxins are unlikely to be formed in the process.
(h) Non-technical Impediments
Nil at this stage.
(i) Preferred Mode of Implementation
Insufficient information was provided by the proponents to determine this, however, the process could be established on a fixed, centralised basis or as a mobile system.
It is difficult at this stage to evaluate when and whether this process will be commercially available for the treatment of scheduled wastes.
|Chapter 3 - Treatment Technologies||Chapter 5 - Base Catalysed Dechlorination|