Automation of a rotating bed reactor for PFAS remediation

Abstract: Properties such as being water and oil repellent and being heat resistant make per- and polyflouroalkyl substances (PFAS) useful in a wide range of products. Since they do not break down in the environment, PFAS pollution makes it way back into drinking water and seafood. They can have negative health effects and standard water treatment facilities can not remove these substances. Spinchem has combined its rotating bed reactor (RBR) technology with a mixed bed resin to construct a water treatment system to treat PFAS polluted water. In this project, I have automated the system to make it more economically viable and investigated the efficiency of the system. This was done by experimenting with different RBR bed geometries and revolutions per minute of the RBR and measuring the time and energy cost for each setup. The PFAS remediation process was modelled with the process of deionizing water for fast and accurate measurements and the experiments were performed with an RBR S14 and Purolite® MB400 resin. From these experiments it was found that the process time decreased with an increased RBR speed while the energy required increased with an increased RBR speed. It was also found that having a thin and tall bed geometry in the RBR gave a faster process, while consuming more energy than having a bed geometry that is wide and short. The results indicated that the geometry of the RBR bed did not show results that could not be achievable by adjusting the RBR RPM. The RBR speed experiments showed that between 125 RPM and 300 RPM, the energy cost increased linearly with reduced time. The process time with an RBR RPM of 100 was significantly longer than with the other speeds. A cost analysis indicated that the major factors to the operational cost of the system is the resin cost and capacity.