A groundbreaking process that could destroy asbestos’ dangerous fibres and transform them into a useful by-product that might replace cement is being tested at the Silverstream Landfill in Wellington’s Hutt Valley.
If successful, the three-week trial by Auckland-based company Environment Decontamination Limited (EDL) of its mechanochemical destruction (MCD) reactor could shake up how New Zealand, or even the world, manages asbestos waste.
“What we’re doing is a mechanical treatment of asbestos,” said EDL’s chief technology officer Dr Kapish Gobindlal at a demonstration at the landfill.
“By mechanically milling or ball milling under high intensity with our reactor systems, we can destroy the asbestos fibre.”
It’s the first test of the reactor outside of the lab, using different variables to formulate the best operating conditions and collect other data.The reactor is one third filled with metallic balls which, when spun at high speeds, smash the asbestos material that’s fed in.
The repeated impact and friction break down the fibrous crystal structure of asbestos, ending up with very fine powder with the property of cement.
The trial will test how much asbestos-containing material to feed into the reactor every hour, the materials’ hardness and properties, or the balls’ size, ratio and materials.
Gobindlal said it could be stainless steel, hardened steel and they previously tested using tungsten carbide, the material used to make drill bits.
Furthermore, samples of the material produced in the trial would be sent overseas for analysis on how it functions as construction material, for fillers or a potential cement replacement.
Currently, most councils in New Zealand bury asbestos at landfills and the only technology to render them harmless is effectively melting it. Gobindlal said mechanical treatment used much more simple systems, would consume 10 times less energy and produce something useful.
“That adds value from something that we believe is a waste, but it’s just a surplus material,” he said.
The company had been working with asbestos since 2016. The expertise from its other projects in nuclear waste and dangerous “forever chemicals” such as PFAS, or perfluoroalkyl and polyfluoroalkyl substances, helped with planning the MCD reactor.
It picked Silverstream for the trial because of the landfill’s infrastructure and ability to safely host pilot-scale activities.
Lower Hutt mayor Fauono Ken Laban, whose Hutt City Council runs the Silverstream landfill, called the trial “innovative, revolutionary and transformative work”.
“For decades, the safest thing we can do with asbestos was bury it. This trial gives us the chance to change that, neutralising the material and putting the end product back to us.”
Laban also reassured residents of their safety during the trial, where it is held at the asbestos cell of the landfill, inside a controlled environment with decontamination units, negative pressure systems and HEPA filtration systems.
“We’re partnered with a world-class organisation where health and safety is at the forefront of everything that they do,” he said.
– LDR is local body journalism co-funded by RNZ and NZ On Air
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