How To Choose Marine Composting Toilets?
Below is a buyers guide for marine composting toilets. First I explain what exactly composting toilets are and how they work. Followed by the types, typical installations and general benefits of these types of toilets for your vessel.
What Is A Composting Toilet?
A composting toilet is a type of dry toilet that separates solid and liquid waste using little to no water. It treats human waste via a biological process called composting. This creates an oxygen-rich environment where aerobic organisms break down the waste.
Composting toilets are good solutions for boats without a space for drainage systems. Alternatively, they are a practical option for use in RV camping or for an off-grid cabin.
It’s important to understand that this type is U.S. Coast Guard-certified and meets all “no discharge” regulations as a Type III marine head.
Types Of Composting Toilets
Composting toilets fall into two categories either self-contained or remote compost systems. They further break down into two types based on their features, these are:
Simple dry composting toilets
A dry composting toilet uses no water, which is why it’s also called a waterless toilet. This type uses a natural air vent but may use a hand crank agitator to speed up the composting process.
Electric composting toilets
This type is a dry compost toilet but adds the use of an electric fan to enhance the process. A small fan creates continuous airflow through the ventilation line. Helping to dry out the solids tank and evacuate odors. An electric composting toilets is the best option for marine environments. Power for this type can be from a 12 volt system or through a standard 110v onshore supply.
How Does A Composting Toilet Work?
To use a composting toilet a user must sit down to do their business. Liquids get channeled to a separate tank or to a holding dank downstream of the toilet. For solid waste, it gets diverted into its own tank or bin. This bin can be a part of the toilet unit or a separate composting tank away from the toilet.
Inside the bin, waste mixes with a carbon additive. Such as sawdust, coconut coir, or peat moss. This mixing creates air pockets in the human waste to promote aerobic action. It also improves the carbon-to-nitrogen ratio and reduces potential odor.
To compost with aerobic action, the toilet must establish and maintain the following:
- The correct moisture level.
- A balance of carbon and nitrogen.
- The right temperature.
To create these three factor the toilet uses an air vent, flapper and a carbon additive. As well, some brands use a method of agitating the tank such as a hand crank. Another component most marine composting toilets use is an integral 12-volt vent fan. This helps to keep the compost dry and speed up the process.
Once the liquid bin is full it’s time to empty it. If you are over 3-miles off shore you can dump over board. For boats inside the 3-mile limit it needs emptying at an approved facility, like a marina.
Inside the solids bin, after the waste transforms it should look and smell like regular soil. Empty the bin into a trash bag and deposit in a dumpster or spread it on non-edible plants.
Install Tips For Composting Marine Heads
Mounting composting marine heads is a simple process as long as you have a spot that allows the toilet to fit. Some will mount on the floor and others can attach to the wall. Most use L-brackets to hold the unit in place.
To start, mark the position of the L-bracket(s). Next, drill the needed holes in the floor, and bolt the brackets down. On most toilets there is a port on the compost bin for attaching a vent hose. Depending on the individual toilet, some may provide the option to attach the hose and fan on either side. Now, determine the route for the vent hose. You have two typical choices, either up through the deck or into an exterior locker, like an anchor locker.
After routing the vent, it’s time to power the vent fan. Most fans connect to a 12-volt DC power source, like a deep cycle battery. Some give you the option of both 12 volt DC and 110 volt AC onshore power. Another solution is to retrofit a solar vent fan to pull air through the vent lines. Sailboat owners who convert away from holding tanks often do this.
To complete the installation, fill the solids bin with the appropriate amount of peat moss or sawdust. That’s it, you’re composting head is ready to use.
Benefits Of Composting Toilets For Boats
Are composting toilets worth it? Yes, there are many benefits to owning a composting toilet for your boat. Including:
Marine Composting Head Are Space Savers
Most composting heads are a special design that are a single unit. As a result, it can be easily installed in vessels with limited space. For boats with a holding tank, adding a composting toilet helps to consume less space too. The holding tank will only hold liquid waste which means you don’t need to worry about emptying it out as often.
Composting Toilets Are Waterless
They don’t need any water for flushing waste which will reduce water use onboard. Less water consumption also reduces the amount of wastewater disposal.
Good For The Planet
A marine composting toilet is an eco-sensitive solution to treating human waste. Using natural decomposition to break down solids’ means there are no chemicals involved. Fewer chemicals is great for the environment.
Simple To Use
Beyond sitting on the unit, the system is easy. Without the use of valves, plumbing pipes or holding tanks, there isn’t much to worry about. There aren’t any moving parts to break down.
* The only caveat here is using toilet paper with a composting toilet. You have two choices when it comes to toilet paper:
- Use single-ply toilet paper as it breaks down faster in the solids bin.
- Have a sealable toilet paper waste-basket to take care of toilet paper. Europeans have done this for years due to their ancient plumbing systems.
Compost Toilets Are Odorless
On many boats with traditional marine plumbing, you might notice a distinct stink. Poor maintained boat plumbing systems are often the culprit. Especially urine caked hoses and holding tanks. With a compost toilet the vent fan takes care of the solids bin while the liquid tank is simple to empty and clean.
Much More Lightweight
Most typical marine heads need holding tanks that can contain around 18 gallons (ca. 68 l) of waste. Whereas a composting toilet might add around 10 pounds of weight until it needs emptying. This is a big weight difference which is paramount on small vessels.