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GETTING RID OF THAT SMELL! BY MICHAEL PIGNÉGUY I t's certainly not unusual when opening up your boat after a period of being closed up, that your sense of smell is accosted by the effluvia from the heads. Even if the head's bowl is clean the attached hoses can become saturated with the smell of the materials that they convey. Then there is the holding tank and all its incumbent fittings with their special problems of leaks and replacement. Toilets that use a fresh water flush system certainly have a much reduced smell problem, but there is still the hose, fittings, and the holding tank problems. While in British Columbia recently I spent a few days cruising on a 52ft launch, the Steveston Lifeboat, that was fitted with a composting toilet and I was pleasantly surprised at how well it performed. Although there were only four on board on this particular trip, the boat was at other times used as a training vessel with a complement of six to eight on board with no problems in the 'heads' department. Like me, before taking this trip, I'm sure that many of you will be thinking that a composting toilet would be a messy and smelly (in the disposal of the effluent) operation. Well, I have to advise that it is a clean and inoffensive operation that has a definite benefit to the environment, both at sea and on land. A brief explanation to passengers on the use of most marine toilets is required on charter boats, and this is also certainly the case with a composting toilet. Hopefully, they would have to be impressed with the benefits to the environment anyway. We are way past the time when everyone should know that they alone are responsible for their own actions when it comes to protecting our increasingly fragile environment. A composting toilet will not only protect the sea, lakes and rivers by the elimination of the discharge of sewage and nutrients, but the land will benefit from a natural fertiliser. INSTALLATION The unit on the Steveston Lifeboat was approximately the same size as the old toilet it replaced, so space was not an issue. All the old hoses and fittings were dispensed with and replaced with one air vent hose and through-deck fitting. Apart from bolting the unit down to the cabin sole, all that remained was to connect a 12volt power source to the unit's in-built fan which runs continuously drawing 0.08amp. A five watt solar panel connected to the house bank batteries easily handles this consumption. And that was that, all ready for operation. If your boat is already fitted with a holding tank, a composting toilet such as this Air Head toilet can be integrated into the system. USE Because this is a waterless operation, a pump is not required for the intake of water and for flushing. What a relief that is! This particular composting toilet has a bowl and an actuator which provides a 'flush'. Before use for solids, a paper bowl liner is placed into the bowl and acts as a carrier for solid matter and paper to be carried into the solid's tank, and a flap in the bowl is manually opened to allow this. Liquids do not generally go into the solid's tank but run into a separate tank on the forward side of the unit. The liquid tank can be removed independently of the solid's tank and has sufficient volume for approximately four days use for one person. 20 Professional Skipper November/December 2012 Because there is a separation of solids and liquids and there being no flushing water, the volume of storage space for the solids is greatly reduced. This model had a US five gallon or 18.9 litre capacity, which the maker says is good for around 80 uses. When turned, a handle on the side provides agitation and desiccation of the solid matter that helps increase the decomposition process, which then renders it non-offensive. WHY IT DOESN'T SMELL Although most of us expect a compositing toilet to smell, it actually doesn't if used properly. The reason is that as soon as the solid matter enters the main tank, the foul-smelling anaerobic bacteria start to die off, and in a few days are replaced by the non-odorous aerobic bacteria. If urine is present in the solids tank this process is inhibited, as aerobic bacterial action is optimised in a dry environment due to the best necessary carbon/ nitrogen ratio being reached in these conditions. Oxygen is required to assist in the decomposing process and this is the problem when disposing raw sewage at sea, or in a lake, as it depletes those environments of the oxygen necessary for marine life. With the composting toilet the oxygen is supplied by the 12 volt fan which is positioned in the ventilator hose at the deck-head. Instead of this 'in-line' fan, a small solar powered ventilator could be installed on deck instead. No smell was noticed out on deck. DISPOSAL OF CONTENTS How often the unit should be emptied very much depends on its use. With a capacity of 80 uses it could be roughly worked out. The longer the contents remain in the tank, with occasional agitation from the handle being turned, the better chance that the contents will dry out, ending up as being quite dry or slightly moist with possibly having a slight musty smell. Although in its pure decomposed form the content of a composting toilet is no longer regarded as sewage, it would pay to treat it as such if discharging while at sea or in a lake. At sea: Current New Zealand regulations state that within the 12 mile limit sewage is not allowed to be directly discharged from an on-board toilet or holding tank: 1 Closer than 500m from MHWS shore, a marine farm or a gazetted matatai reserve. 2 Closer than 200m to a marine reserve. 3 In less than five metres of water. On land: Emptying the solids tank will not be a daily chore, but once the matter has reached a stage of being decomposed, it can then be used in an ornamental garden, around fruit trees, or for real gardening types it will go very well in a compost bin. Emptying the urine tank will be more frequent and it easily disconnected and carried with a convenient carrying grip to dispose of its contents overside. BENEFITS No hoses, apart from the ventilator, no pumps, no blockages, no through-hull fittings and no holding tank required. Easily installed and cheaper overall than a standard marine toilet with all its required fittings. Non-polluting and beneficial to the environment. And, da daaa…! No smell!