Left to right: the Air Head, the SunMar EcoLet, ûand the plumbed-through office toilet.

The safe disposal of human waste in the waters of the world is a major problem today. A steady increase in the number of boats and a growing awareness of how easy it is to damage a fragile environment have made it less feasible to simply chuck the waste overboard—laws against this kind of discharge are getting tighter with each passing year.

This has left boaters with three alternatives: head offshore to a point where it can be legally dumped, store it until it can be pumped out to a shore-based treatment facility, or pre-treat it to a point where it's safe to dump it in a legal discharge area. …