In a move that builds on current ecological processes to create energy, Stanford researchers are developing a system that turns sewage waste into rocket fuel. Exploiting the fact that bacteria operate in high concentration in sewage waste, researchers are looking to turn their byproduct, nitrous oxide (laughing gas), into a viable energy source for rocket thrusters:
Stanford professor Brian Cantwell specializes in designing rocket thrusters that run on nitrous oxide, also known as laughing gas. He and some of his grad students wanted to use nitrous oxide as an emissions-free energy source. While nitrous oxide is a powerful greenhouse gas, when it’s burned as rocket fuel, the only byproducts are hot oxygen and nitrogen.
The development of the substance as fuel is an answer to the problem that excess nitrous oxide had previously presented waste management systems. Although anaerobic bacteria are more cost effective for sewage treatment, their byproduct proved to be another costly and dangerous obstacle to resolve. The sewage/bacteria/rocket thruster fuel conversion system presented here accounts for each byproduct with as little environmental impact as possible.