im guessing a portion of the sewer gases would need to directly drive a pump to have a flowrate and then the methane could be changed to a liquid hydrocarbon close in weight. between doing this and melting pennies i would be rich. this is the closest thing to free energy as it gets. even if i heated a home with it that would be a success. for a wood fire in the home, giving it a sewer gas intake would allow low methane not to extingish or lower reactor(stove) temp; the quality of combustion would remain good.