According to NASA, roughly "1,000 pounds of methane are produced on International Space Station and dumped overboard as waste gas every year"[1].
It seems like an awful waste to just get rid of it. The Morpheus Project page talks about possibly using the methane as fuel, it's curious that they don't do that already. What is all that methane gas a byproduct of, and why can't it be used for something more productive?