The traditional way of dealing with the methane generated in the waste treatment is to burn it off – an utter waste. Why would anyone do this? Gas companies spend millions of dollars every year drilling and fracking to collect natural gas, which is mostly comprised of methane. By using anaerobic digesters sewage is converted into methane and the solids that are left over can be used for fertilizer or as building material. Next, the methane is sent to a plant to be further refined before it can be used for electricity.