Small quantities of methanol can actually go right into the sewer system. I know it sounds odd, but methanol is destroyed pretty quickly by microbial digestion. It may be different in different areas, but that is what I was told by water treatment people here in St. Louis, when we were asking about the effects of small quantities of methanol getting into the sewer system as a byproduct of biodiesel production. They said, "If its less than a liter at a time, its no problem." You just don't want to overload the system.
peace,
sam