Impurity-specific water purification technology and its implication in biofuel distribution systems

Biofuels are taking the center stage in the total energy portfolio and their utilization is increasing both in the stationary and transportation sectors. The production of two commercially available biofuels, biodiesel and ethanol, has more than doubled since 2005. Fuel ethanol production is legislated to increase to 60 billion gallons by 2025. As fuel ethanol increases in the distribution system, the likelihood of small spills into the ground water is likely that must be monitored and removed. Water utilities dealt with a similar issue when methyl tributyl ether (MTBE), an octane enhancer fuel additive, was discovered in the wells in the 1980s'. The Environmental Protection Agency (EPA) regulations on water quality are becoming stringent but so are the detection methods. The sophisticated analytical techniques allow water utilities to detect certain impurities down to parts per trillion (ppt) levels. One approach is to modify present method of water purification to remove biofuels. Biofuels are oxygenated compounds and as such could be categorized with other oxygenated volatile organic compounds (VOCs') found in water wells. The standard method is to use Granulated Activate Carbon (GAC) that can effectively remove essentially all the VOCs' but it is not very effective for all the organics. The less adsorbed compounds elute fast and slowly the "breakthrough" occurs and the GAC batch must be replaced, a costly step. We are taking the following multi-step approach to develop a VOC removal method. First, the impurities are being categorized, the properties of various available GACs' are matched with those of categorized impurities and develop hybrid GAC bed that delays "breakthroughs". The talk will discuss the approach and merit of such a method.