New methods pave the way for efficient removal of PCB
8/06/2020
Article by Ms. Katrine Hauge Smith (DANISH TECHNOLOGICAL INSTITUTE) included in EDI Special Publication 2020
The Danish Technological Institute (DTI) has tested two innovative methods for the removal of PCBs from buildings and construction waste. Both methods have proved effective, and there is great potential in further developing and optimizing on both methods.
PCBs are widespread in the Danish building stock and the substances may pose a problem for the indoor climate in buildings.
Sometimes there is so much PCB in a building that it poses a health risk to the building’s users. At thesame time, the PCB also poses a problem when the building is demolished, and the construction waste has to be treated.
Together with the companies Tscherning, DAB and RenoSyd, the Danish Technological Institute has just completed a project with support from the Environmental Technology Development and Demonstration Program (MUDP) under the Danish Environmental Protection Agency. In the project, the partners have investigated two technologies that can remove PCBs in buildings and construction waste.
One is thermal treatment of the building with electrical panels that can remove PCB-related indoor air problems from the building and the other is microwave treatment of construction waste that can remove PCBs from the waste so it can be recycled, explains Katrine Hauge Smith, senior consultant at DTI and project manager for the project.
Electric panels provide flexibility for thermal heating
Today, thermal treatment is performed by heating an entire building, but we have investigated whether there is potential in using smaller and more flexible heat sources in the form of electric panels, so that you can just heat parts of the building.
With the flexibility of the electric panels, you can heat one room at a time, which means the building can be used during the renovation, and not least that the entire building does not need to be heated, says Katrine Hauge Smith.
Thermal treatment with electrical panels has shown to be a promising technology for removing PCB pollution. The technology is currently only 10% less cost effective than traditional thermal treatment but has great potential to be optimized.
The technology requires an optimization of power consumption, for example with heat control, as well as a flexible rail system that makes the electric panel mobile.
From undocumented waste to recycling
Although in Denmark there is a requirement that PCBs must be removed from the building before it is demolished, we know that this is often not done.
And once the construction waste arrives at recycling sites, it can be difficult to document the cleanliness, since the waste comes from many small sources.
In the project, we have investigated the use of microwaves to remove PCBs, which has the potential for undocumented construction waste at recycling sites. The project shows that processing of PCB contaminated building waste in the microwave is a promising technology.
Here, however, power consumption must also be optimized before the technology becomes as profitable, both economically and environmentally, as when the PCB is removed from a building.
But there is clearly a great potential to purify especially the “undocumented” waste from “the many small sources” with this technology.
If successful, we will be able to ensure that far more construction waste is free of PCBs and thus send more of the construction waste for recycling, Katrine Hauge Smith says, emphasizing that it will make sense that both technologies are further developed with a focus on optimizing power consumption, which is the aspect that environmental and economic analysis has identified as crucial.
