This Small Business Innovation Research Phase II project will build upon the data compiled during Phase I in which Selenium Ltd. worked with university and commercial partners to develop a novel anti-biofouling technology to be deployed in water filtration membranes and membrane spacers. The technology explores the use of organo?]selenium compounds and their ability to generate reactive oxygen species (ROS) while being covalently bound to a substrate. As biofouling remains one of the largest problems to be solved in water filtration, the integration of the proposed technology into numerous filtration components at the point of manufacture emphasizes the technology?fs flexibility and capability to mitigate this problem in a commercially viable and economic way. The objectives in this Phase II project will be to optimize integration strategy specific to the manufacturing parameters of each filtration component (i.e. feed spacers, polyamide reverse osmosis and polysulfone ultrafiltration membranes, etc.). Further objectives will be to integrate organo-selenium compounds into pilot scale modules, developing a data set measuring antifouling capabilities in real world scenarios with the help of commercial partners. Selenium anticipates the results of this project will concretely identify the technical integration strategy and added value for delivering produced water at reduced costs.
The broader impact/commercial potential of this project is based on the notion that mitigating the industry problem of biofouling will reduce energy and maintenance demand, thus decreasing the costs associated with water filtration and produced water. Furthermore, the technology has broad applicability to a number of other filtration markets such as pharmaceutical and oil and gas, which could benefit equally from the reduction in biofouling. As the necessity to produce drinkable water from a growing number of sources emerges as a leading societal need, the ability to reduce costs positions the technology to be deployed worldwide allowing for populations across the world to benefit. By increasing the efficiency to produce drinkable water from sources such seawater and wastewater, water producers may produce drinkable water at reduced costs with less cleaning. The ability to combat biofouling continues to be an ongoing area of development. While a broad spectrum of technologies have been employed to explore antifouling properties, few have had much success. Should the technology substantially reduced the problem of biofouling while proving viable in the commercial manufacturing of filtration equipment, it could be considered one of the most influential innovations the filtration market has seen in the past decade.
The purpose of the NSF Phase II grant was to develop a commercially viable Reverse Osmosis (RO) spacer product to reduce the biofouling in RO modules. Selenium, Ltd., in collaboration with subawardees, Texas Tech University and Texas Tech Health Sciences Center, industry experts, consultants, resin compounders, spacer manufacturers, and reverse osmosis element manufacturers, successfully completed and surpassed all Phase II research objectives. Specifically, over the last two years, the Company was able to professionally masterbatch its proprietary Seldox™ compound, have commercial grade spacers manufactured, test spacers in numerous dynamic and real world environments, test said spacers for efficacy and risk, as well as transfer, and scale synthesis to a commercial manufacturer. Lab bench tests of commercial spacers demonstrated a 3.22 log reduction of total specific biomass concentration versus E.coli, and a 3.76 log reduction of total specific biomass concentration versus S. aureus. Furthermore, biofilm thickness (µm) was reduced by 4.32 logs versus S. aureus and 3.84 logs against E.coli. As fouling occurs in RO modules, the pressure needed to maintain the flow rate increases. This yields higher energy demands as well as long down time for module maintenance. Because of its importance, Selenium monitored the flux loss throughout the course of each experiment. Since the system was operated at a constant pressure, the net change in permeate flux was a major indicator of the occurrence of fouling during each experiment. For experiments using the city wastewater, control feed spacers experienced a permeate flux loss of 73 ± 16% over the course of the trial. When the selenium grafted feed spacers were used in the trial, permeate flux loss was reduced to 38 ± 9%. For experiments using Semiconducter wastewater, control feed spacers experienced a permeate flux loss of 92 ± 3%. When the selenium feed spacers were used in this same system, permeate flux loss was only 23 ± 5%. The effect of organo-selenium commercial spacers on flux loss is important as they may enhance RO performance by increasing treatment efficiency while reducing energy consumption. With the work conducted through this grant, it can be observed that Selenium’s Seldox compounds may allow RO facilities to use their RO modules for longer periods of time with lower energy demands. Furthermore, because of lower microbial growth, facilities may no longer have to use harsh chemicals to clean and maintain their equipment. All these factors may lead to lower RO processing costs and environmental concerns. Going forward, Selenium is focused on assisting commercial partners in conducting large scale in situ tests, scaling compound production to meet the demands of commercial partners, and ultimately bringing a new technology into the water treatment industry.
