Micro-Hole Membrane for Solid-Liquid Separation of Micron-Scale Particulate

There is great demand for low energy dewatering technologies to harvest very fine particulate, such as microalgae. Current dewatering methods (e.g. centrifuge, press filter) consume much energy and are less effective for separating high value micro-particulate. One promising method for very low energy dewatering is capillary solid-liquid separation; but its processing rate for the most valuable microparticle because the small pores that trap particles also present too much resistance to water flow. This SBIR project is developing a novel microhole separation membrane that combines high water flow with the need small pore size. In Phase I, advanced laser micromaching techniques were used to create and optimize versions of this microhole membrane. These were tested at bench scale in conjunction with capillary separation and showed performance far superior to existing membranes for dewatering and capturing microalgae 5 microns and smaller. In Phase II the speed of fabrication will be increased to commercially affordable levels, and the membrane will be turned into a prototype belt for demonstration on a pilot scale capillary separation machine. Commercial Applications and Other Benefits: If successful, this technology will enable scaling of low energy capillary separation to address dewatering, harvesting and water purification in a wide array of industries. Capillary separation exploits the principals of liquid adhesion and was originally developed with support from US Department of Energys Advanced Research Projects Agency (ARPA-E). It has been described as transformative because of its ability to dewater suspended solids using less than a tenth of the energy of incumbent methods like centrifugation. Using the microhole membrane to help scale this technology can slash energy use and processing costs in the areas of algae and biofuels, pharmaceuticals, nutritionals, food and beverage, chemicals, and corn-based ethanol. An entire range of alternative applications exists in the field of water remediation, effluent and sewage treatment, as for example from energy producing anaerobic digesters, with the potential to capture valuable co-product as well.