Asbestos has been one of the biggest things we’ve had to contend with in recent years regarding home renovations. Every time we want to make changes to our aging housing stock, we have to consider asbestos testing to confirm the presence of asbestos, then expert asbestos removal when we find it in an area we can’t safely manage.

But there’s one part of asbestos removal that very few of us generally consider, and that’s asbestos dumping. What happens to asbestos once it has left our homes, and is landfill truly our only option?

As it turns out, no. Microwave thermal treatment of asbestos, which involves heat treatment to make it safe, could be on the horizon.

How Do We Dump Asbestos in New Zealand?

Currently, after asbestos materials like asbestos roofing are removed from a New Zealand home, a qualified asbestos removalist will arrange for it to be transferred to an authorised dumpsite.

Typically, this is a contained area away from general waste dumping sites that complies with the Resource Management Act. Asbestos removalists also dump all smaller asbestos materials into two layers of heavy-duty plastic bags with twisted and tied tops, adhesive tape, and asbestos warning labelling.

While this dumping process has been the procedure for several years and has stopped people from coming into contact with asbestos waste accidentally, it has never seemed like the ideal solution. But that ideal solution may not be too far away, thanks to thermal treatment of asbestos.

Socially and Environmentally Responsible Asbestos Disposal Alternative

Wolverhampton, United Kingdom company Thermal Recycling believes they have found the solution to the unsustainable practice of asbestos dumping.

In November 2020, they opened a demonstration plant that diverts asbestos from landfill and turns it into a new asbestos-free material. It can then be broken down to create a sustainable aggregate.

How Does Thermal Treatment of Asbestos Work?

Turning asbestos into a safe product essentially involves heat treatment. The heat denatures the asbestos, which consists of changing the asbestos’ characteristics with control, precision, and a touch of science.

By the time the chemical and physical transformation takes place, the asbestos is no longer asbestos. When the demonstration plant was opened, they tested over 350 asbestos samples after they had been through kiln treatment. When they were analysed, no asbestos was detected.

But tests simply stating they didn’t contain asbestos wasn’t proof enough for Thermal Recycling. They also put the materials under an X-ray fluorescence and X-ray diffraction to look at the asbestos structure. They determined that it was no more hazardous than any other material.

How Does the Microwave Thermal Treatment Plant Operate?

The heat treatment plant involves a moving hood kiln that lifts, moves, and repositions over a kiln base. It contains a burner system with a temperature control unit that carefully monitors the temperature.

There is also a filtration system to remove any volatile organic compounds, particle matter, and fumes. These are cleaned before being exhausted into the atmosphere. The entire plant also includes HEPA filtered local exhaust ventilation, which removes dust from the atmosphere at a rate of five air changes an hour.

The kiln is designed to take asbestos cement sheets, which are removed from construction sites in specially-designed ‘load bags’. Plant workers load the bags onto the kiln base, and the hooded kiln system, as previously mentioned, is lifted and moved over the base.

Once the heat is applied, the denaturing process begins to remove the asbestos. The entire process takes around 24 hours. Once it has cooled down, workers remove it from the kiln, and it becomes crushed to produce a recyclable aggregate product.

 Thermal Recycling chairman Graham Gould said he was delighted about the announcement of the demonstration plant.

“We can’t continue putting asbestos in landfill sites for future generations to deal with,” he said.

What About Other Safe Asbestos Waste Methods?

So far, Thermal Recycling’s innovative heat treatment plant is proving to be one of the most effective asbestos waste solutions available. However, that doesn’t mean we’re not trying to come up with other solutions, as well.

In 2019, Terri-Ann Berry from Unitec was working on a way to break down asbestos into a non-hazardous form using bacteria and fungi. Terri-Ann believes this could one day allow for asbestos composting, even though we are “some years away from asbestos treatment facilities in New Zealand”.

According to Tony Edmonds from The Board consultancy, which advises Chemcare, recycling asbestos-contaminated products is a “100 percent inevitability”.

What Do We Do with Asbestos in the Meantime?

Because the technology doesn’t yet exist in New Zealand to turn asbestos into safe materials, there’s only one thing we can do. We must hire licensed asbestos removal teams to not only remove the materials from our homes safely but dispose of them safely at authorised landfill sites.