Toilet Composting » marine composting head

Composting Toilets for Boats: General Features and Requirements

M Day — Wed, 15 Jul 2009 22:39:21 +0000

There are many reasons to consider switching to a marine composting toilet for your boat. Composting toilets provide an excellent alternative to holding large amounts of waste during sailing expeditions, or to discharging chemically treated waste into open waters. Even though the starting costs run around $1200 for most composting toilet models, they can still be quite a bit cheaper than outfitting a boat with a standard marine head and holding tank.

And besides these practical advantages, composting toilets have additional environmental advantages to consider as well. A compost toilet will help save on water usage, eliminate the need for chemicals to treat waste, and produce a valuable end product that can be used in place of chemical fertilizers around trees, flowers and other plants.

However, composting toilets also present certain challenges for boaters as well. They must be constructed so as to be able to handle a considerable amount of turbulence. There is a problem regarding the space requirements of many self-contained composting toilets, and the power requirements as well: most composting toilet models require that a vessel have enough power so that they can run a 12-volt, 4 watt fan continuously, and a heating unit occasionally (to control moisture and prevent odors).

Fortunately in recent years several manufacturers have stepped up to the challenge and started to produce composting toilets meant specifically for marine use. The Sun Mar Mobile is one such example. With this model, the Sun Mar corporation created a special mechanism to ensure the composting drum is always held in upright position during “violent motion.” They also developed a special gasket system around the finishing drawer to ensure there are no leaks from it as well during rough weather. Space modifications features were put in place to that more vessels can accommodate them (such as fold-up foot rests) and special filters were installed for the vent stack so there are no odors at deck level. The model is not cheap, however, and starts around $1600, but it is an excellent example of a composting toilet built specifically for marine uses.

The space requirements will still be a challenge for smaller craft, however. If you are considering purchasing a composting toilet you need to ensure that it will be able accommodate the number of people using it, otherwise you will end up with an overflowing toilet with unfinished compost inside. The Sun Mar Mobile is suitable for one person, possibly two, but would not be able to accommodate any more people except for occasional outings. You will also need to provide some space to store the dry carbon matter that is used instead of water for these models (sawdust and peat moss are probably the most commonly used materials). And you need to ensure that there is adequate space to be able to remove and empty the finishing drawer once the compost is ready.

If you are interested in learning more about the composting process, you should read the article “Toilet Composting Basics.” If you would like to learn more about what you can do with the finished compost from a composting toilet, read “What is Humanure and What Can I Do with It?“ Otherwise, return to the Toilet Composting Homepage, where you will find many additional articles and resources regarding composting toilets.

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Marine Composting Toilets

M Day — Wed, 15 Jul 2009 15:55:53 +0000

Marine composting toilets (boat composting toilets, or marine composting heads) can be a great addition to any vessel, and can help solve many problems that boaters encounter when it comes to holding and emptying toilet waste. However, many composting toilets may be considered too large to use on small vessels, although composting toilet manufacturers are increasingly working on creating models better suited for both the space requirements and the motion requirements needed for marine toilets.

Because the composting toilets manufactured for marine use are self-contained models, you will need enough space to accommodate both the toilet itself as well as room to pull out the composting drawer. There will be no additional plumbing required for most models. However, in order to lessen potential for odor and to help maintain the composting system in order, most system use a fan and your boat will need to have adequate power to be able to continuously run the fan (usually 4 watts, 12 volts).

In terms of cost, marine composting toilets can compare quite favorably against the cost of other marine toilet systems, particularly those that require a holding tank for waste. Most marine composting models run around $1200 or more. Although it may be tempting to go with a slightly cheaper self-contained composting toilet not built specifically for marine uses, you may regret this decision due to the specific challenges boats present in terms of properly containing the waste during bad weather.

For example, the Sun Mar Mobile composting toilet, probably one of the most sophisticated marine composting toilets currently on the market, currently costs around $1600. It can be used by one to two people full time use, and possibly accommodate even more for weekend outings. Sun Mar has put a lot of effort into designing a toilet that will deal well with “violent motion.” For their mobile unit, they made sure that the finishing drawer was gasketed in a manner so that absolutely no liquid could escape, and they also built a special drum locker that could ensure that the composting drum is continually held in an upright position. Additional special modifications for marine units include such features as fold-up foot rests and activated carbon and zeolite filters to ensure that there is no odors on the deck where the vent stack protrudes.

From an environmental standpoint, marine composting toilets are beneficial for multiple reasons, but not the least because they do not require any chemical additives, require no water to maintain, and create an end product (humus) that is a valuable soil additive that actually benefits the environment (instead of a waste product that needs to be treated and disposed of properly). The compost that is produced by marine composting toilets is absolutely sanitary and can used to fertilize a wide variety of plants and trees (for more, read “What are the Environmental Benefits of Composting Toilets?” and “What is Humanure and What Can I do with It?“)

Self-contained composting toilets are generally Coast Guard Certified Type III MSD. For more information about composting toilets, you can also read “Toilet Composting Basics” or return to the Toilet Composting Information Home Page, where you will find dozens of informative articles about composting toilets.

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