A Powerful Byproduct.

This article discusses the evolution of the biogas energy system at the Hyperion Wastewater Treatment Plant in Los Angeles, California over the past half century. According to the authors, the system was designed with several diesel/biogas engines which were very reliable. However, they produced too much sulfur dioxide and nitrous oxides to meet air quality standards. The engines were replaced with fluidized bed which used vanadium catalysts and then chelated iron and activated carbon to remove pollutants. Later gas turbines were used, but they required frequent maintenance so steam boilers were added.