I agree most boating literature and personal comments consider urine separation to be the holy grail of a composting toilet. The boat we had to make a toilet for did not have the space available for a separation scheme. Research into the Humanure sawdust toilet indicated separation was not needed and was actually counterproductive to composting. The Humanure instructions were followed and both my son and I had very positive experiences, although we used different bucket toilets on different boats with different mediums.
The commercial composting toilets in reality do not seem to be an actual composter, but a depository for solids until the contents can be composted. The urine needs to be dumped frequently, perhaps daily. The difference appears to be that a commercial composting toilet empties the solid tank every several weeks and empties the urine tank daily while the sawdust toilet empties the tank about every three days for a couple. I have no experience with the commercial products but I do read the posts describing how much the urine jug can smell. i think the commercial units are good products and better than a holding tank sanitation system. None would fit the Baba 30.
The toilet for the Baba 30 is a collecting toilet, a different concept than a composting toilet. If you wish to compost, that option is available. It could be argued that placing the contents into a dumpster is composting in a way. I suspect this would be beneficial to the mass deposited into a landfill. This toilet is a simple device that will fit into the smallest of cruising boats, is ecomonical to build, simple to operate, inexpensive to run and does not smell. Composting is at the bottom of a list of objectives. The top objective is no smell!
We have used plain sawdust, pelletized sawdust, red cedar planer shavings, bald cypress planer shavings, pine planer shavings, cross cut paper shreds and peat moss mixed with all the above. All of the media worked well, but the sawdust was the cleanest and easiest to use. We gravitate to the pelletized sawdust because it is the easiest compact material to obtain. It stores in about 1/4 the space that planer shavings and raw sawdust occupy. It is easy to rehydrate. It is pretty much dust free. It smells good. It is easy to handle. It costs about $6 per 40 pound bag in the Houston, Texas area. John plans to store it aboard in the clear 1/2 gallon pretzel canisters. By our experience and Humanure data, a 40 pound bag will last approximately 30 days for an average size couple.
Once we got the design working, we thought that the smaller cruising boat community might like to hear about our experiences with this marine sanitation system.
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