The catalyst for developing the microwave extraction apparatus dates back to the Technology Research Laboratory established in 2002 (currently the Eco-Innovation Promotion Department). When it was first established, it had a staff of just two people. We rented a room at the Business Incubation Center located on the grounds of the Industrial Technology Center of Kochi Prefecture and commenced research on microwave heating jointly with the center.

The first project we tackled was "sludge volume reduction" collected and transported by powerful vacuum trucks. At the time, since we anticipated mounting the system on vehicles, we focused on microwaves using electricity as a heat source rather than equipment using fire such as boilers. In addition, considering operational safety, we adopted a "vacuum drying method" so that the sludge temperature would not rise excessively.

First, we investigated microwave generators and found that many industrial microwave oscillators were expensive due to performance guarantees. Therefore, as our research budget was small at the time, we purchased a cheap microwave oven at a home electronics retailer, extracted the microwave generator called a magnetron, and built a prototype for Experimental Unit No. 1, which was about the size of a bucket. Subsequently, we produced Unit No. 2 fitted with eight magnetrons, and about two years after starting our research, we succeeded in developing a vacuum drying technology to efficiently dehydrate sludge. However, even though we could efficiently reduce the volume of sludge, the sludge itself lacked added value, making the processing cost unfeasible, so mounting it on a powerful vacuum truck was never realized.