Fouling in a high pressure, high recovery rotating reverse osmosis system

Concentration polarization and membrane fouling have limited the efficiency of reverse osmosis. Rotating filtration may minimize the effects of concentration polarization and membrane fouling by increasing the shear at the membrane surface. A second-generation high-pressure rotating reverse osmosis device was designed to perform long-term tests of the purification of a complex wastewater ersatz based on what is expected to be produced on a long-term space mission. A significant amount of fouling occurred after three days of operation during the tests. The fouling potential was used to characterize this fouling and was incorporated into a theoretical model of rotating reverse osmosis. The effect of cleaning cycles and a biocide on the reduction of flux due to fouling was investigated. Cleaning cycles every 48 h significantly improved the flux of the device. The addition of a biocide reduced the fouling including the sharp decrease in flux at day three, which can therefore be attributed to biofouling of the membrane surface.