Saturday, February 28, 2015

Composting marine head, revisited.....

NOTE:  If you find the following post too descriptive I'm not sure you will enjoy long term sailboat life.

Its hard to believe that it was over 6 years since I first mentioned the idea of installing a composting marine head on TIH.  The idea was rapidly knocked on the "head" by the boss.

Times have moved on, we now know a number of cruisers who have installed and love their composting heads.  Lynne has stated that she "might" be open to the idea.  Ok!  It helps that we have two heads on board, the forward one is a Lavac connected to a holding tank.

There are three main marine composting head manufacturers / suppliers (correct me if you know of more);

The Airhead

Nature's Head


The one that I am most interested in is the Airhead.  I like the overall design and was impressed when I met and spoke to the aptly named Geoffrey Trott.  Do your own research and pick the one that works for you.

 Firstly, let me clarify a few points for anyone unfamiliar with marine toilets and composting toilets.  

1.  Body Waste (Urine and feces) does not magically disappear after we use the toilet, despite what modern society would have us believe.  This fact becomes painfully obvious when on a boat.  If you poo on a boat someone will have to deal with it later.  If your boating experience consists of touching a lever with your foot, hearing a reassuring whoosh and seeing everything disappear then you are on a power boat.  This is the ubiquitous VacuFlush system, which just means that you have hoovered the shit down a series of pipes into an inaccessible place deep in the boat. It will sit there, feeling annoyed and plotting.  

2. It is illegal to dump untreated waste inside the three mile limit.  You can dump "treated waste", unless you are in a NO DISCHARGE ZONE. "Treated Waste" requires a Electro Scan or similar device.  No discharge zones are becoming more common and will continue to do so.

3.  Your boat will require a holding tank to hold the waste until it can be pumped out at a pump-out station,  pump-out boat or outside the three mile limit.  From my research most live-aboards have to pump the holding tank every 3 to 5 days.  This is  PITA.  I you secretly dump your holding tank into the bay / harbor at night eventually karma or the Marine police will catch up with you.

4.  Holding tanks require hoses and pumps.  These have to be changed out at various intervals.  I you choose to install the standard macerating 12v pump you can count on this being an annual event.  If your macerating pump has worked flawlessly for 6 years and you tell me, it will hear you and die. 

My point is that if you live on a boat you will have to get up close and personal with poo at some time, or pay someone else to do it.

Enter the composting marine toilet;

1.  The lower container is partially filled with moistened coconut fiber or peat moss.  This is sealed off with a trap door.  You can either poo directly through the open trap door or onto a paper coffee filter with the trap door closed.  Opening the door then allows the coffee filter and its contents to drop through.

2.  Because of the limited time the poo stays in the toilet in does NOT actually compost.  It is simply mixed with the peat or coconut fiber.  Because urine is separated you are not dealing with the Porta Potty effect (i.e. a slurry of waste in a bucket).  I am reliably informed that the smell is minimal.

3.  Urine is diverted into a smaller forward tank which has to be dumped every three days.  On the Airhead (and possibly on others) there is a connection to pump this urine into a holding tank.

4.  A tiny computer type fan is constantly running and vents the head, via a hose, above deck. 

5.  Every 60 or so uses (said to be a month for a cruising couple)  you will have to;

     a.   Remove the top section of the contraption.

     b.   Empty the contents of the lower section into a plastic bag.

     c.   Dump the bag and its contents in a suitable site.

If you or someone else on board can't handle this then a composting marine head is not for you.

A few other minor issues; 

1.  I have heard that bug infestation can be an issue.  The vent hose has a screen.  Sometimes users have resorted to bug killing chemicals to control this.

2.  Dumping of the poo/fiber mix in a sealed plastic bag in a dumpster appears to be legal or at the very least a grey area.  It will be interesting to see how this evolves.  I'm sure the Diaper industry will have a major say in any attempt to regulate dumping and at the very least buy the appropriate politicians.

Long story short, the installation of a composing toilet on TIH is a POSSIBILITY.  To this affect I borrowed one (not use) from a friend and did a test install.  Much thanks to Karen from my neighboring Whitby 42 who acted as a model.