Environmental sustainability initiatives are becoming important as the combined effects of human resource utilization and climate change are placing an increasing demand on the earth’s resources and ability to absorb waste materials. As a result, treatment of wastewater sludges is now considered an important component of a comprehensive water conservation and use strategy.  Organic waste sludge treatment typically occurs as a multi-step process within a single reactor that involves anaerobic fermentation of complex organic materials into fatty acids, acetate, and carbon dioxide (CO2) and hydrogen (H2) gases.  Acetate and H2 are then converted into methane (CH4) by a second type of microbe. Although water reclamation is a desirable achievement, this process creates end products (CO2 and CH4) that contribute to climate change and exacerbate water management issues. Moreover, the methanogenic microorganisms that convert acetate into CH4 are sensitive to the environmental conditions of the reactor system; imbalances in pH or reaction materials can inhibit these bacteria.

Drexel University has recently developed a novel way to treat biodegradable organic materials that provides a more environmentally friendly approach to waste water sludge treatment. In this process, hydrogen is continuously removed from the reactor system and captured for alternate energy uses while eliminating the methane producing step. Other potential valuable biofeedstocks such as acetic acid are also removed and the remaining end products including CO2 are recycled into the reaction mixture. Not only does this approach overcome traditional problems encountered in anaerobic digestion while reducing the formation of greenhouse gases, it also enables the recovery of low molecular weight organic acids and hydrogen that can provide alternate fuels or biomaterials.