New approach to PFAS treatment

September 3, 2024

MSP Corporation (CEO: Takashi Yabe, Professor Emeritus at Tokyo Institute of Technology) conducted a reduction test of PFOS and PFOA with the cooperation of Kakamigahara City, Gifu Prefecture, and succeeded in reducing the levels by 80% in one treatment. Not only is further reduction expected by treating twice, but by improving part of the equipment, a dramatic reduction effect is expected. The equipment is very simple and currently has a daily processing capacity of 1 ton, but it can be scaled up and is fully capable of processing tens of thousands of tons per day as required by various local governments.

PFAS (fluorinated organic compounds), a collective term for PFOS and PFOA, are used in a wide range of applications, including waterproofing, coating frying pans, cellophane tape, and fire extinguishing agents. However, these compounds are difficult to break down, and are considered to pose a risk of causing cancer when accumulated in the human body, and are subject to strict regulations in various countries around the world. Interest in PFAS is growing in Japan as well, and as testing is being carried out in various areas, the number of municipalities exceeding the regulatory limit is increasing. For example, Settsu City, Osaka Prefecture, has detected 21,000ng/L, which is 420 times the national regulatory limit.

Furthermore, PFAS are used in the semiconductor industry as materials for photoresists and other products, and as construction of semiconductor manufacturing plants progresses across the country, this issue will become unavoidable.

A common removal method is to adsorb PFOS and PFOA to activated carbon, but there is a concern that disposing of the activated carbon may lead to further contamination. Therefore, it is necessary to incinerate the activated carbon at high temperatures (1,100 degrees) to break down PFOS and PFOA, but this goes against the principles of the SDGs (Sustainable Development Goals). In addition, there are household water purifiers that remove PFOS and PFOA, but because they use membranes, the discarded membranes become a new source of contamination, or incineration is unavoidable.

Our equipment was originally manufactured to extract magnesium from seawater, and has a track record of reducing the salinity of seawater to 0.00%, as well as purifying ink and contaminated water from wastewater treatment plants. The purified water achieves an electrical conductivity of 1mS/m, the standard for pure water. We have also succeeded in separating tritiated water, an achievement that was published in the Journal of Nuclear Science & Technology in 2023. Separating tritiated water was previously considered impossible, but our original approach was highly praised by the reviewers of the paper.

Conventional reverse osmosis (RO) equipment uses membranes to filter seawater, but when salt adheres to the membrane, it stops functioning and the membrane must be discharged into the ocean, raising the problem of an increase in the salinity of the surrounding seawater. On the other hand, our equipment does not use membranes and collects salt and magnesium as solids, making it a completely new seawater desalination method that does not require discharge. This technology has already been commercialized and patented.

This feature allows us to collect substances in water without using membranes or activated carbon, and was applied to the PFOS/PFOA reduction experiment. This technology is applicable to all of the nearly 10,000 types of PFAS. Removal methods that use chemicals are limited to a certain number of substances, and the chemicals themselves pose new problems after removal, so our method, which can remove all substances, is extremely important.

Features of this test machine

No chemicals are used, allowing for safe and environmentally friendly processing. This device is designed to recover salt and magnesium from seawater, and can recover all solids generated during the processing process. Since it does not use adsorbents such as membranes or activated carbon, no replacement parts are required, significantly reducing maintenance work and costs. Ultimately, all PFAS can be recovered in solid form and reused. In addition to electricity, various thermal energies such as solar heat and waste incineration heat can be used as power sources, allowing for sustainable operation. By expanding the scale of the device, it is possible to build a system with a processing capacity of 20,000 tons per day.