Composting is the controlled aerobic (atmospheric oxygen-using) biological decomposition of moist organic solid matter to produce a soil conditioner. Because it requires molecular oxygen, it cannot be immersed in water (saturated).

The emphasis is on “controlled.” This sets it apart from the uncontrolled decomposition that occurs in the natural environment. A leaf falls from a tree branch to the forest floor, and microbes transform it into a nutrient form that the tree can consume. The biochemical process is the same.

In a composting toilet, the objective is to transform potentially harmful residuals — mostly human excrement — into a stable, oxidized form.

The primary microorganisms responsible for composting are bacteria, actinomycetes, and fungi. However, algae, mixomycetes (slime molds), viruses, lichens, and mycoplasmas are other organisms present in the compost process. Soil organisms, such as protozoa, amoeba, nematodes, earthworms, and arthropods, also perform major roles by degrading surface litter — consuming bacteria and assisting in aeration.

Back To Top

1. Put on gloves and dust mask
2. Bridge the inner and outer doors (bottom and up the sides) with heavy duty aluminum foil to keep the solids from falling in between the chamber and fouling the bottom where it cant be easily removed
3. Shovel the contents into a biodegradable and compostable bag then remove the foil and close the inner and outer doors.
4. Bring the bag to a burial site (away from foot traffic) and add a few buckets of water to the bag contents to hydrate the contents as it will only decompose when moist
5. Dig a hole and bury the bag under 6 inches of top soil under some trees or bushes where the nutrients will do the most good.
6. Dispose of the gloves, dust mask and the aluminum foil in a municipal solid waste container.
7. Mark and date the disposal site and enter it in a log that can be shown to health officials if necessary

Back To Top

A composting toilet system (sometimes called a biological toilet, dry toilet, or waterless toilet) contains and controls the composting of excrement, toilet paper, carbon additive, and, optionally, food wastes. Unlike a septic system, a composting toilet system relies on unsaturated conditions (material cannot be fully immersed in liquid), where aerobic bacteria and fungi break down wastes, just as they do in a yard waste composter.

Sized and operated properly, a composting toilet breaks down waste to 10 to 30 percent of its original volume. The resulting end product is a stable soil-like material called “humus,” which legally must be either buried or removed by a licensed septage hauler in accordance with state and local regulations in the United States. In other countries, humus is used as a soil conditioner on edible food crops.

Back To Top

A batch composting toilet system utilizes two or more interchangeable or movable bins. One is filled at a time and then turned aside allowed to cure while another bin fills — just as with twin-bin and triple-bin yard composters. By not continually adding fresh excrement and urine to older, more advanced material, the material decomposes more thoroughly, uninterrupted by the added nutrients, pathogens, salts, and ammonia in fresh excrement. Also by dividing the material, it can have more surface area, and thus better aeration. Batch systems require monitoring the level of the bins to determine when a bin has filled and a new one must be moved into place. However, because there is more surface area and the material is divided, there is often less or no mixing and raking of the material.

Back To Top

Properly installed and maintained, composting toilet systems will contain, immobilize, and/or destroy pathogens — organisms that cause human disease.

Still, when planning composting toilet systems, pathogens and vectors (flies and crawling insects) need to be considered. This is a particular concern in areas with endemic diseases, such as warm regions, where pathogens flourish.

Back To Top

Containment: Pathogens cannot survive for long, once they have left the human host. They have co-evolved over thousands of years with the human race and can thrive only within the narrow chemical and environmental parameters of the human body. Containing the excreta for an extended period of time brings about the death of pathogens and reduces the risk of infecting new hosts through ingestion —the primary pathway for enteric pathogen transmission

Competition: The competition among composting organisms for available carbon and other nutrients is intense.

• Human pathogens become food for the well-adapted aerobic soil organisms that thrive in the Carousel.
• When the available nutrients are consumed, the microorganisms begin to consume their own protoplasm to obtain energy for cell maintenance. When this occurs, the microorganisms are said to be in the “endogenous phase.”
• When these organisms die, their protoplasm and cellular matter is digested by other organisms.
• Eventually, if no new food sources are presented, all the energy will be released and the matter fully oxidized. The end of this phase results in an end product that is stable and safe.

Antagonism: Some composting organisms produce toxic substances that harm, inhibit, or kill other organisms. For example, the actinomycete Streptomyces grieus produces streptomycin, a well-known antibiotic. The soil bacterium Bdellovibrio bacteriovorus parasitizes the infamous Echerichia coli (E. coli) and multiplies within the host cell, eventually killing it.

Adverse Environmental Factors: Factors such as pH, temperature, moisture, and ammonia content also play important roles in pathogen multiplication or death.

Back To Top

To install a composting toilet in a new home or as part of a renovation of an existing system, you might need a permit from local or state agencies. (Strictly speaking, you should get a permit for any installation.)

What your state and local agent will allow might limit your options and might rule out site-built systems. Some states have approved systems based on their own research, some do it on a case-by-case basis, and some require NSF listing. Check with your board of health agent first before you buy.

Back To Top

Performance is the composter’s ability to safely manage the excrement for the number of people who will use the system on a daily basis for the number of days it will be in use. Research the various systems and decide what you think will work best for your situation. See also Capacity Issues.

Back To Top

Lifestyle relates to what you can live with, both in terms of maintenance and aesthetics.

• Are you willing to maintain the system yourself and how often? Or do you prefer to pay for routine service?
• Do you mind being able to see the contents of the composter? Or worry about the occasional fly? If not, consider a toilet stool with a trap of some kind or at least a view barrier.
• Be sure you can manage the tasks detailed in the instructions or are willing to pay a service person to do them. Read between the lines: operation and maintenance instructions cannot present the sensory (sight and smell) experiences associated with dealing with a system up close and personal.
• Some composters require manual mixing of the excrement, toilet paper, and additive (ETPA) with a rake or a pitchfork while it is composting.
• Others require turning mixing device handles. Others have automated this process, but that means more components that break and wear out eventually. Fixing an internal mechanism in a composter can be an unpleasant task. If this bothers you, call a professional, such as your local septage pumping and hauling or sewer cleaning service organization, and arrange to have these tasks performed on a regular fee-for-service basis.

Back To Top

The toilet seat is attached directly to the composter and the whole unit usually sits on the floor of the toilet room.

Back To Top

Also known as remote or bi-level systems, where the toilet is on the floor, but the composter is on a level below or adjacent to the toilet room. The larger central systems are usually easier to live with, as they provide more processing volume and thus are more forgiving and allow longer intervals between maintenance tasks. Central systems are used mostly in year-round homes and public facilities. And they allow you to use a vacuum or gravity microflush toilet.

Back To Top

Do not assume that nonelectric cottage composting toilets perform as well as their electrically heated and power-ventilated big brothers. You will be disappointed, if you think you can use a nonelectric cottage composting toilet full-time, year-round for a family of three and more. It won’t work without some kind of supplementary system, such as urine diversion, leachate drainage, and passive heat.

Non Electric systems cannot actively evaporate leachate with only ambient air temperatures and passive chimney effect. Power venting is always recommended, even if it is from a 12V battery source. Make sure exhaust pipes are at least 4 in. in diameter with no bends or obstructions, and make sure ventilation is as direct as possible.

Back To Top

Many composting toilet systems must be positioned below the floor underneath the toilet or in a separate building. If you use a waterless toilet, the composting toilet system must be positioned directly beneath the toilet. It can be a few floors down, but there should be no angles in the toilet chute. Remember: “chute straight”. Your composting toilet system does not have to be in the basement. Laundry and utility rooms are also potential locations. If you have no basement or sufficient crawl space, your most likely options are to install a vacuum-flush toilet system or to use a self-contained composter. (again, if you do not want to manage this, call a professional.)

Back To Top

Leave Plenty of Space for Maintaining Your Composter! When locating the composting toilet system, consider how it is going to be maintained and emptied. You must provide an easy-to-clean area with easy access to outdoors for removing compost. If the system will be maintained by a sewage hauling company, make sure the company’s equipment can access the composter. It’s best to consult the sewage hauling company before you install the composter.

Back To Top

Servicing a composter in a tight space is tricky; the air quality might be bad, and raking and removing the end product difficult. Warning: Many odorless and invisible gases, such as carbon dioxide, carbon monoxide, sulfur dioxide, methane (natural gas), and radon are heavier than air and can fill up a foundation from external sources and displace the oxygen-carrying atmosphere. You cannot survive in such an anoxic environment. If you or a service person climbs down into the room that contains these gasses, you could be in big trouble and not know it until you pass out from lack of oxygen.

Back To Top

You must provide adequate space for making connections to the toilet, exhaust pipes, leachate drains, and routine service. It might be helpful to consult with a licensed plumber regarding regulations for installing composters, leachate drains, exhaust pipes, and gray water drains.

Back To Top

Most composting toilet systems require electricity to operate heating or forced ventilation exhaust systems (fans).

If you do not have adequate power, be it 110V or 220V alternating current or 12V or 24V direct current, your only option is a passive composting toilet system (sometimes simply called a non electric composting toilet). Remember that the performance of these toilets is not as predictable, and they require exhaust pipes of at least 4 in. or more in diameter, with no bends or obstructions.

Back To Top

Some promotional brochures for composting toilet systems show the unit under a cottage exposed to the elements. However, after you buy the toilet, you might see in the operating manual that the unit must be kept at 65°F (18.33°C) to operate properly.

A frozen composter might never thaw out — even during summer months, because its insulation prevents the summer heat from penetrating the ice in the fiberglass or plastic composter. Even electric heating during the summer might not bring the toilet to operating temperatures before the cottage is shut down for the season. Then the system is more a holding tank than a composter.

Back To Top

As you know, composting happens faster when it is warm. Too-low temperatures will slow down the process. (Some composters are also heated to evaporate leachate.) That means that composters might need to be heated where ambient temperatures are too low for active composting, such as northern USA, Canada, Scandinavia and most of Europe

Because faster composting means faster reduction of the material, heating is a way to increase your composter’s capacity. At the same time, the warmer the process, the more you should monitor moisture, as heat dries material.

To get heat to your composter:

Warning: To be safe, don’t let your heater get wet, if it’s not designed to be wet. Keep it away from flammable materials. Always make sure your heating system is installed in accordance with state and local building codes.

1. Locate the composter in sites that are already warm.

2. Connect the composter to warm air sources.

3. Heat and insulate the composter itself. If your system doesn’t come with a heater, you can buy and install a small heater, such as those used for fish tanks.

Back To Top

Locate your composter in an interior heated room, such as just under the second floor bathroom. Then you do not need to insulate the composter. Keep the ambient temperature at a minimum of 65°F (18.33°C). Or locate your composter near a South-facing window. Or next to a boiler, furnace, clothes washing machine, dryer, or water heater.

Back To Top

Look for cheap or free heat, such as wasted heat. Some composters have convenient air intakes that can be connected to a warm air source, such as:

• An insulating fire proof box with an incandescent light bulb in it
• A heat exchanger connected to the exhaust system of a generator or the flue from a gas hot water heater
• The lint-filtered exhaust from your clothes dryer
• Hot discharge air from your air conditioner or dehumidifier
• Solar heat from a solar collector, window, or a greenhouse
• In the summer, hot air pumped from your attic via a fan-powered duct
• A connection from an existing space heating system
• Bread box solar heater

More sophisticated systems like heat pumps, while elegant from an engineering point of view, are often cost prohibitive for use with a composter alone.

Back To Top

For solar heating, you have to have available solar energy, such as a clear, unobstructed south-by-southeast opening, not blocked by trees or other buildings. In most North American communities, 8-12 square feet of solar hot air collection area all year long will sufficiently warm a composter in a heated home. Contact your state solar energy association for collector designs.

There are many designs for heating small outhouses with composters in them. Some designs direct solar heat onto the composting mass through a south-facing window, some onto the leachate, and some onto the composter.

Note: Direct solar heat can dry out the surface of the mass, creating a crust that actually insulates the center, so you might actually need more heat. Turning the material and adding water helps.

Back To Top

You can also zone the location for your home heating system or hot water heater to provide heat to your composter. Think of it as heating a small room in your house.

These numbers are gross fuel data. Heating appliances have different efficiency ratings, so ask your local supplier to tell you the conversion factors relevant to your specific application. Electric heating has the lowest cost to install and the highest cost to operate, but it might be the most economical for seasonal use.

Back To Top

Increasing temperature can increase the rate of processing – within certain limits.

Back To Top

The process of ventilating and exhausting the composting toilet also sends heat out of your composter. Toilet flush water also cools it. Evaporating leachate can cool the process, too, through evaporative cooling. So do not overdo the exhaust system. To minimize the heat loss, install a fan speed controller to keep the fan speed at levels just adequate for odor control, but not high enough to cool and dry the compost too much. Turn down the fan speed until you smell odor in the bathroom. Then turn up the fan just a little until the odor goes away. This should be sufficient.

Or, place a lit incense stick inside the toilet, if you see smoke coming out of the bowl, then there is not enough ventilation or exhaust. A rate of 1 to 5 cfm (cubic feet per minute) should control odors and provide sufficient oxygen to the process.

This heat loss also underlines the value of using warm air sources:

• Insulate the vent pipe, if it passes through cold unheated spaces, to prevent condensation — the vapor from evaporated water and urine, which will run back into the toilet. Keeping the exhaust chimney warm encourages throughput of the vapors.
• Or paint the un-insulated vent stack black and put it in its own window or a greenhouse facing south. Solar chimneys help maintain a draft. (This is a little complicated and heats only the pipe on sunny days.)

Back To Top

Ensuring that air enters (ventilation) and exits (exhaust) the composting toilet system in the right direction is critical for maintaining the composting toilet system and preventing odors from entering the home.

If your toilet room is on the side of the house opposite the prevailing winds, wind pressure on the windward size of the house pulls a vacuum on the opposite or leeward side. So, when you open your bathroom window on the leeward side, odor will be pulled from your toilet and into the room. You will know that this is the case if the window curtains blow out. If they blow into the room, then the toilet is pressurized, and no odor will come into the room.

This is not as much of a problem with fan-forced ventilation/exhaust systems, because the fan can overcome the negative wind pressure. However, when the fan is off, well, that’s another story. This is not a problem with systems with trap-seal toilets.

Wind turbines work in areas with steady strong winds but according to a National Forest Service study can actually impede air flow at wind speeds of less than 10 to 15 mph.

Instead of the wind turbine, A simple plumbing tee at the top of the pipe both keeps the rain out and provides sufficient venture action effect (whereby wind sucks air out of the pipe).

Sophisticated extractors, such as the Vacu-Stack™ available from wood stove dealers, both keep out the rain and increase the rate of exhaust extraction when wind blows across rigid foils arranged in a globe fashion around the pipe opening.

Back To Top

Some assume that the wider the connecting pipe from the toilet to the composter, the less chance of streaks going down it. That’s probably true; however, this connecting pipe can act as a chimney through which odors can back up into the toilet room. In fact, the larger the diameter of the connecting pipe and toilet seat opening, the greater the chance of odor.

• However, the taller the exhaust pipe, the greater the chimney effect and effective odor exhaust.
• To reduce the toilet-as-chimney effect, make sure that there is not a negative pressure in the toilet room, so air is not pulled up the connecting pipe.
• Disconnect or reverse the bathroom exhaust fan. (The composter’s exhaust can take its place).
• Be aware that whole-house attic fans, fireplaces, wood stoves, and air conditioners can pull odor from the composter into the building.
• Fans are built into many composting toilet systems, and usually their speeds cannot be regulated. These fans will pull air into your composter from either the toilet room or wherever the air intake is. Make sure this is not cold air that will cool your composter. Yes, that might come at a cost, as the composter exhaust fan can suck in as much as 100 cu ft of air per minute (100 cfm or 2.83 cmm) from the building, increasing your heating bill.
• That’s another reason why a fan-speed controller should be installed with a powerful fan (25 to 100-plus cfm or .7 to 3.0 cmm), so that you can set the minimum amount of fan power to control odor. Again, most composters will need only 1 to 5 cfm (.03 to 14 cmm) for adequate aeration for composting, so your primary issue with fan speed is managing odor.
• If the toilet room is cooler than the composter, heat might rise from the composter into the room.

Back To Top

The odor from the composter will not normally be noticed on the ground outdoors if the exhaust pipe terminates at least 12 in. (305 mm) above the peak of the roof. If the exhaust pipe is lower than the roof peak, odors from the exhaust pipe might be swept to the ground through wind downdrafting.

Odor filters, can be installed in the exhaust pipe after the fan and before the pipe terminus

Some manufacturers, such as Sun-Mar Corp., include air diffusers that mix the exhaust gasses with fresh air to dilute the odors and help promote updraft.

Back To Top

In a waterless situation, gravity is the only way to convey excrement and toilet paper from toilet to composter, so the composter must be almost directly under the toilet, although it can be several floors down. There should be few, if any, angles at all. Do not underestimate the viscosity (stickiness) of excrement.

If you cannot establish such a location or if you decide that aesthetic and life style issues dictate a barrier between you and the composter, a microflush toilet stool or a vacuum-flush toilet system are your alternatives.

Back To Top

If the diameter of the connecting pipe for your toilet is too large, odors are most apt to enter the toilet room, insects have better access to the composter, and pets, toys, and infants could fall in (although we have yet to hear of a child falling into a composting toilet system).

• If the pipe diameter of your connecting pipe is too small, the pipe gets caked with excrement and might discourage ventilation/exhaust and require frequent cleaning. A good size is 8 in. to 12 in. (203 to 305 mm).
• Just check the outlet dimensions, so that you can get the necessary adapters to connect the toilet to the composter you have selected.

Back To Top

When deciding what capacity you need for your composting toilet system, consider:

• How many people will likely use the system every day?
• For large-capacity applications, also ask: How many people will use it every year?

Most manufacturers classify their models by how many people can use the system during a specific period of time and still have the system produce an acceptable end product. This classification takes into account the composter’s ability to contain and compost excrement and toilet paper, plus its ability to contain or evaporate excess leachate.

Caution: Before you buy a composting toilet system, you must understand the formula that each manufacturer uses to classify models. The formulas differ unless they were tested under a uniform performance standard, such as NSF/ANSI International Standard 41 or the basis for Product Label’s Nordic Environmental Labeling Criteria for Closed Toilet Systems.

Back To Top

Most small, self-contained appliance composters were designed for seasonal use only. When a manufacturer states that a model should be used only for seasonal or cottage use, then the number of users listed is usually for 20 to 60 days out of a 365-day year. Manufacturers of seasonal systems usually list a much smaller number of users for residential (365-day) use.

European manufacturers use the person-day (PE) approach (one person over 24 hours). For example, a toilet with 600 person days of capacity means one person could use the system for 600 days or four people, 150 days.

Some composters sized for public facilities are rated by uses per year, as many public facilities measure usage this way. The problem: The usage of a public facility can vary widely; parks have found that systems rated for 3000 uses per year cannot manage when 2000 of the park’s uses can occur in two months!

Back To Top

In a capacity rating, one person is an average adult (male and female). However, women can use three to four times more toilet paper than men, as women use toilet paper after urinating and men usually do not. The table shows the capacity rating developing by one study.

Urine and Feces Produced by Average Northern European Adult

Back To Top

The ratio of urine-to-feces volume varies in different settings. In a day-use facility, there will be a much higher ratio of urine to feces — as high as 10 to 1. However, in a residential setting, a ratio or 3 to 4 is common. So a predominately day-use facility will need to consider a system for managing leachate (lots of urine) more than feces.

Back To Top

The size (volume) of the composter is an important factor, but not the only one. The processing rate can be speeded up by increasing aeration (including thorough mixing or batching) and raising the temperature.

A composter is not just a storage tank, so buying a larger composter does not mean you will get the same efficiency of processing that you will get in a smaller one. The larger the chamber, the more important it is to get air to the composting material and avoid compaction. You might even consider installing two smaller ones instead of one larger one.

Large volume does have advantages: Larger systems serve more users in a fixed time period. They allow longer retention and processing time (for a fixed number of users), which might produce a more thoroughly processed end product. Larger means fewer maintenance events too.

Back To Top

Cost alone is usually the last consideration when choosing a system, because the cost factors are driven by the first four categories: Location, temperature/heat, ventilation/exhaust, toilet stool, capacity.

It can be all too easy to choose a composter model based on purchase price alone. It could be a costly mistake.

Of manufactured systems, the small self-contained composters are purchased for seasonal second homes and cottages. Because they are used only 14 to 30 days a year, they are much smaller and less expensive than large central systems. However, be careful when selecting any appliance composter for residential use. Yes, it might have been tested for a limited number of persons in continuous use by a small family, but you might soon become weary of the daily and weekly routines required to keep it operating well. Self-contained composters such as Sun-Mar composting toilet systems, are highly mechanized, but while they are small and lower priced, their operating, maintenance, and lifecycle costs can be much higher. The size of larger composters might require a significant modifications to your house. Consider those costs, too.

Back To Top

Check with local authorities to determine if approvals are required. In Massachusetts, only plumbers are permitted for installation.

Back To Top

Lifestyle issues

• Are you willing to maintain the system yourself? How often?

• Or do you prefer to pay for routine service?

• Do you mind seeing the composter contents? If not, get a trap of some kind or at least a view barrier.

• Do you need a large system for year-round use? A small system for a vacation home?

Installation Space Requirements

• Does the system require space underneath toilet in a basement or appropriate crawl space? Consider a vacuum toilet or a separate room (laundry or utility room), or separate building

• How much floor space (footprint) is required?

• How much headroom is required for making connections

• Is there adequate space for connections, exhaust pipes, leachate or graywater drains, and routine service?

• Can you provide an easy-to-clean area with easy access to outdoors for removing compost?

• If the system will be maintained by a sewage-hauling company, can its equipment access the composter? Consult with the company.

Plumbing and Venting Issues

• U.S. or metric pipes

• Exhaust pipe diameter

• Exhaust pipe insulation diameter

• Standard plumbing fitting/pipe

• Location of vent pipe termination

• Fan-forced exhaust required

• Supply air (is there  and required temperature

• Exhaust system

• Leachate drain

Power Requirements for Heating or Fans

• Voltage: 110 to 220 VAC (12 to 25 VDC)
  Amperage

• Nonelectric option. See exhaust pipes 4 in. or more diameters with no bends or obstructions.

Heating Issues: Composter must be kept at 65°F (18.33°C).

• Specified temperature for rated performance?

• Accommodates supplementary heat?

• Air intake for connection to warm air source?

• Location? (South-facing window; next to boiler, furnace, washer, dryer, or water heater; interior heated room; for example, under second floor bathroom)

• Heater options (if needed)

• Self-regulating heating cables

• Heat exchanger

• Conventional heating system: Electrical, forced hot water, forced hot air

• Compatible heating devices: Aquarium heater

• Radiant floor heater (electric or hydronic)

• Heated room

• Dryer duct and lint filter

• Hot air discharged from your air conditioner or dehumidifier

• In the summer, hot air pumped from your attic via ducts

• Bread box heater

• Solar heat

Service Issues

• Leachate drains provision?

• Frequency of service at rated capacity?

• Parts available for old models?

• Support for old models?

• Can it be upgraded?

• Maintenance contract availability?

• Access space required for service?

• Are such components available from local sources?

Back To Top

Urine is the fluid secreted from the blood by the kidneys, stored in the bladder and discharged by the urethra. In healthy humans, it is amber colored. About 1,250 milliliters (about a third of a gallon or 0.044 cu ft of urine are excreted in 24 hours with normal specific gravities of 1,024. Flow ranges from 0.5 to 20 milliliters/minute with extremes of dehydration and hydration.

Composition of Urine Normally Produced Daily by an Adult

Source: Van Nostrand’s Scientific Encyclopedia

Back To Top

A range of 6.7 to 182 grams (.23 to 6.4 oz) of nitrogen-containing constituents are excreted by one person in 24 hours. Many studies give the average daily output for a healthy adult at 11 grams.

The average northern European adult produces about 40.6 fluid ounces (1.2 liters) of urine and 20.3 fluid ounces (0.6 liters) of feces daily. In one year, the same person produces 155.8 gal (589.77 liters) of urine and 57.9 gal (219.18 l) of feces. Just one person!

Back To Top

The nutrients in urine can cause overgrowth of aquatic plants in lakes, rivers, and streams. When they die and decompose, they use up oxygen in the water, which suffocates other aquatic, life such as fish. This is called hypoxia

When it gets into drinking water supplies, nitrogen can result in such diseases as methemoglobinemia or blue baby syndrome. To protect public health, The Safe Drinking Water Act now requires reducing the nitrogen through tertiary treatment, often involving expensive denitrification equipment.

Back To Top

Urine has had a bad rap in many cultures due to its association with the smell and disease-causing nature of feces, according to Jan-Olof Drangert of the University of Linkoping in Sweden. In his paper, “Perceptions, Urine Blindness and Urban Agriculture,” Drangert reports that this has not always been the case; throughout history, urine has been used for beneficial purposes.

He reports that in Sweden, urine has commonly been used to clean wounds and, to some extent, to drink as therapy. Recently urine has been shown to have a disinfectant property. In the Danish countryside in the 19th century, urine was stored and used as a detergent for washing clothes and yard dying. A century earlier, European artisans collected urine and canine excrement for industrial uses. U.S. military survival training manuals say it is safe to drink one’s own urine if no drinking water is available.

Back To Top

The 155.8 gal (589.77 liters) of urine produced by one person in a year is a significant load for any composting toilet system to manage, so dealing with it separately offers some advantages. Draining it for immediate use is the most direct solution. Consider the following for one person:

• To evaporate one gallon would require a minimum of 9000 BTUs (2.6 KwH) of energy (enthalpy of about 1044 BTU/lb or 87°F). However, so much is lost in the transfer of heat, you would likely require more BTUs of fuel.
• To store it would require at least two 55-gal (208.20-l) drums.
• To soak up one year’s worth of urine into a moist carbonaceous form, so that it will compost (minimum 50 percent moisture by weight) will require at least 980 lb (441 kg) of an absorbent, such as bone-dry sawdust. That might require a lot of material. For example, sawdust has a density of 12 pounds (5.4 kg) per cu ft, so you might need 82.5 cu ft (2.3 cu meters) of dry sawdust to soak up 115.7 gal (437.97 l) of urine.

If you plan to use urine for fertilizer, it needs to be oxidized to a plant-available nitrate state first or diluted and mixed into well-aerated soil, where the aerobic microbes will complete the oxidation (nitrification) process.

• To utilize effectively the nutrients in urine:
• Drain urine combined with graywater directly into an aerobic soil system. Drain urine from the urinal or urine-diversion toilet, combine it with graywater, and use it on site; no storage necessary.

Note: Urine is high in nitrogen. Graywater is high in carbon from soaps, detergents, and hair conditioners and low in nitrogen. Combine the two, and you have a better effluent to use in a planted system. However, both contain a lot of sodium, so be sure to use salt-tolerant plants. Collect the urine for later use. Drain the urinals or urine-diversion toilet to storage tanks that can be carried or pumped to the point of use; for example, an orchard. Then the urine should be diluted. For one part urine, dilute it with eight parts fresh water, because the urea and salt in urine is too concentrated for most plants. The diluted urine should be sprinkled on the soil, not on the plants. The soil microbes will oxidize the nitrogen-containing compounds to a form that the plants can best utilize.

• The bacteria mostly responsible for converting urea into a nitrate are Nitrobacter and Nitrosomonas. These nitrifying bacteria need carbon for their protoplasm, cell walls, and enzymes that convert organic nitrogen molecules to nitrates. For a more specific inoculate, you can grow a Nitrobacter-Nitrosomonas culture by mixing urine and sugar, letting it process aerobically, and adding this to the urine barrel or composter

Back To Top

Remember that the carbon-to-nitrogen (C:N) ratio of urine (8:1) is too low for microbes to use and fully break down into a plant-usable form. To preserve all the fertilizer value of urine, a carbon-to-nitrogen ratio of 25:1 is needed to convert all the nitrogen to nitrates by aerobic soil bacteria. (Again, nitrate is the form of nutrient that plants use best.)

But that would require loads of high-carbon materials such as wood chips, peat moss, and so forth. Most of us are not on a farm that could provide enough straw or leaves from trees for this purpose. And, remember, that the primary use of additives is to provide pore spaces for air, not to provide carbon.

Instead of adding a room full of sawdust (C:N 400:1) to a year’s worth of urine to achieve C:N 25:1, consider adding some more concentrated forms of carbon, such as sugar.

Why add sugar to a urine composter? Sugars are the most “available” of all carbohydrates and can provide a lot of carbon with little volume compared to straw, leaves, and wood chips. These are primarily difficult-to-digest celluloses and lignin that, in a composter, are decomposed by fungi and actinomycetes – not by bacteria.

Sugar, however, is a simple carbohydrate. Adding some cane sugar might not seem ecologically elegant, but it will surely adjust the C:N ratio, in place of a truckload of sawdust. About a third of a cup of sugar per person per day should do it. Diverting and using urine might seem on the “lunatic fringe” now, but the benefits of doing so are hard to ignore, and it will be a “common sense” practice in the future.

Back To Top

In one year, the average northern European adult produces 116 gal (439.11 l) of urine. Many studies give the average daily nitrogen output for a healthy adult at about 11 grams That figure ranges widely, mostly depending upon diet. The more plant or animal protein the population consumes the more nitrogen it excretes.

Two Swedish university studies report that one northern European adult (who consumes plant and animal proteins) produces enough fertilizer in urine to grow 50 to 100 percent of the food requirement for another adult. We excrete these nitrogen-containing compounds as urea, creatine, ammonia, and a small amount of uric acid. These nutrients could feed a hungry and growing population at a lower cost than producing more expensive chemical fertilizer.

The world needs all the nutrients we are flushing away each day in our urine. Given the far-reaching costs of using manufactured fertilizers, utilizing this valuable and usually sterile resource deserves more consideration. Urine costs nothing to produce (unless you count the plant and animal protein we eat), but it does have storage and transportation costs, as does commercial chemical fertilizer.

Back To Top

Leachate can be difficult to manage because, as the water evaporates, sludge forms, which should be removed periodically. It can clog screens, grates, and filters in some composters; block outlet holes and openings, drain hoses, and pipes; and harden on internal mixing equipment — causing maintenance headaches over time.

Some composters have fittings that can be connected to drain pipes. A marine bilge pump can be used to manually pump out the leachate from most composters.

Back To Top

Some composting toilet systems, especially the cottage models, have internal electric heaters to evaporate leachate. They are usually effective, but they require a lot of energy – about 9000 BTUs per gallon. At 10 cents per kWh, that’s about 30 cents a gallon (3.79 l).

Back To Top

Draining leachate with a drain line lowers your handling of the leachate. Generally, you should drain it to:

• A tank that is pumped out by a septage hauler;
• A septic system (septic tank and leach field);
• A system to be combined with graywater for irrigation of plants such as the Ecocyclet.

U.S. regulators usually require that leachate must either be evaporated inside the composter or removed for transport to a conventional treatment plant.

Leachate can build up, but many people think it occurs only during peak use or power outages. In the authors’ experience, it does collect, even in composters with electric heaters. So, it is better to provide an easy and automatic means of removal, such as a gravity drain line or pump.

Leachate can be recombined with filtered graywater for subsurface aerobic irrigation; it is a natural combination of nitrogen and carbon for plants. You can also dilute it with eight parts water to irrigate biologically active soils with non edible plants. (Wear gloves!) Remember: Leachate and graywater contain nutrients for soil microbes, which transform them into plant food.

Back To Top

With proper engineering, a composter can drain leachate through 1 to 2 in. (25.4 to 50 mm) drain pipe. This large size prevents clogging by solids and allows larger volumes, should a flush toilet be used.

Note: Drain lines should be vented. Many codes require separate venting for any drain system, but you might be able to use your composter’s vent system.

Install a union (an easily separated connection) between the composter and a vented drain to allow servicing of the drain line. If you can, place the composter on a raised platform, so leachate will drain out by gravity (and maintaining the composter will be more convenient).

Back To Top

Many individuals and communities worldwide are diverting and using urine for several reasons

• In wastewater, urine accounts for most of the nutrients — as much as 90 percent of the nitrogen and potassium.
• These nutrients can get into groundwater and lakes, rivers, and streams where they can pollute by over-fertilizing aquatic plants.
• The nitrogen in urea is quickly converted to ammonia, which is toxic to composting microbes and causes odor.
• The fertilizer value is lost when the ammonia in it evaporates and escapes up the exhaust pipe. For that reason, some might overestimate the nutrient value of composted human excrement.
• Urine adds more water than is necessary to compost feces and toilet paper. The moisture content of the feces (66 to 80 percent), plus the addition of toilet paper, is sufficient for good processing.
• The excessive salt (sodium chloride) we put in our foods is excreted in urine. Salt is toxic to living organisms in amounts above their minimum requirements and can inhibit the composting organisms. Further it can turn into “salt concrete” in locations where removing it is difficult and can “gum up” the composter’s mechanisms.
• Oxidized and diluted, urine makes a good liquid nutrient for plants.
• Although most of the nitrogen is either drained away as leachate or evaporated, it would require significant amounts of carbon (25 parts of carbon for one part nitrogen) to provide the optimum ratio to convert the nutrients in urine to a plant-available form. For some systems, that would require wheelbarrows full of additive.
• Several studies validated the collection and use of urine to fertilize crops, such as wheat, corn, and oats.
• Urine is usually sterile in healthy populations.
• Urine is portable and easy to collect separately and drain away.
• Urine mixed with feces produces a malodorous compound — worse than each of its components alone.
• When urine is combined with feces, certain malodorous compounds form, which do not form if they are kept apart. The bacterium, Micrococcus urea, is the responsible culprit.
• However, collecting and using urine presents some challenges:
• The urea in urine degrades rapidly to the gasses ammonia and carbon dioxide, unless it is contained or directly utilized.
• Urine contained without air will smell bad.
• Urine can be diluted and immediately used on plants. When it is used immediately, however, it has not been transformed into a plant-available form; one is relying on the soil microbes in the plant bed to do that. To preserve all of the fertilizer value of urine, it needs to be oxidized or composted. (an aerobic process.). For this, a carbon-urine mixture requires a carbon-to-nitrogen ratio (C:N ratio) of one part urine to 25 parts carbon to convert all the nitrogen to nitrates by aerobic soil bacteria. Nitrate is the form of nutrient that is available to plants.

Our bodies keep urine separate naturally, so we can collect and use it separately. Urine-diverting toilets which feature a urine collector and drain cast into the front of the toilet bowl opening, make urine collection as easy as using a flush toilet.

Back To Top

For easy maintenance and repair, be sure to provide convenient access to the emptying door as well as the liquid draining system, the exhaust pipe system, and the electrical service connections for any heating system and fan. (If flooding is a concern, it should be at least 18 in. above the high flood line.)

Ensure that the support or floor where the composter will be placed is dry and strong enough to support the load. The composter should be placed on an insulated, level, flat, and stable surface, such as concrete, compacted earth, moisture-resistant and rot-resistant lumber, or similar material.

If the floor is cold, such as in a basement, insulate the composter bottom to prevent heat loss with a minimum of 2 in. closed-cell foam insulation board. FOAMGLAS™ insulation from Pittsburgh Corning Corporation is best because it is rigid cellular glass foam, will not burn, or become unstable and has constant insulating efficiency and zero moisture permeability. It is expensive and hard to get, but you need only a small piece of it.

Back To Top

Consider locating the composter 2 in. to 18 in. (51 mm to 457 mm) above the grade of the floor. This will allow easy access (less stooping) for routine maintenance. Also, an elevated composter creates a grade drop, so you can better drain the leachate into another area or container.

Note: Draining leachate is mostly an issue with composters that do not have power-assisted evaporation systems.)

A self-contained appliance composter that sits on the toilet room floor has a fixed height from the floor to the toilet seat, but you could place it on a platform to make the removal area easier to access. Doing this, however, raises the height of the toilet seat. Remember to include the space needed to pull out the end-product removal drawer.

To move leachate horizontally you will need to provide a downward pitch of ¼ in. per linear ft (6.35 mm per linear meter). For example, if the destination is 4 ft. away from the leachate outlet, a one inch drop is required to drain it by gravity. (Typical pitch for clear, fresh water is ⅛ in. (3.3 mm) per linear foot, but leachate contains suspended solids, so it requires a steeper pitch.)

Elevating the system might not be necessary if the composter has access doors at knee level or higher or if there is an integrated leachate collection tank with an automatic pump.

With a self-contained composter that has a drain in the rear, such as the Sun-Mar composting toilet system, it can be helpful to shim (elevate) the front ⅛ in. to ¼ in. (but no more), so that liquid drains to the back. This will encourage drainage of the leachate. Your hardware store can provide you with beveled shims, or you can use cedar roofing or siding shingles. Be sure to keep the unit from tipping from side to side. Of course, you might choose to shim it only just before draining the system.

Back To Top

Always read the installation instructions and plan the installation before making any cuts in the composter, your building, or the exhaust pipes. To provide more flexibility in locating the pipe (to permit alignment of the toilet-connecting pipe and/or the compost removal door), use flexible synthetic rubber no-hub connectors as unions to facilitate servicing and repairs. They will also serve as vibration-absorbers that reduce noise from fan motors.

Note: In the Carousel, the air-intake opening is in the center of the composter lid, and it might be covered with a plastic cap, which should be removed. Consider connecting a hot-air supply duct to the air-intake opening to provide warmed air to the composter. Or you can simply cover it with a tube made from rolled-up fly screen.

Back To Top

When installing a microflush toilet such as the SeaLand Traveler™ with a composter, remember that drainage is tricky. One pint (half a liter) of water cannot move solids in excrement and toilet paper laterally or horizontally unless the pitch is a 35 to 45 degree angle down from the toilet to the composter. The steep downward pitch required for one-pint toilets is far greater than that for conventional toilets, because a well-designed 1.6 gal (6.06 l) flush toilet has a drain-line carry of 59 ft. at ¼ in. per ft. pitch in a 4 in. PVC pipe. (A 6-liter flush toilet has a drain-line carry of 17.9 meters at 6.35 mm per meter pitch in a 101-mm PVC pipe.)

Issues of optimum pipe diameter versus pitch are critical, as a given portion of excrement and toilet paper will not move unless there is sufficient water behind it to push it through or to lift and float it through the pipe. There is an optimum pitch and pipe diameter for every mix of solids and liquids:

• If the pitch is too shallow, solids will drop to the bottom and the liquids will slowly seep away.
• If the pitch is too great, then the liquids will precede the solids and the solids will drop out.
• If it is correct, the flush surge will lift up the solids and carry them down the pipe.
• If the pipe diameter is too large, then the sidewalls of the pipe will not be scoured by the water, and the energy in the water will be too diffuse to move the solids.
• You might not know that a problem exists until several portions of solids have blocked the pipe – and then it is too late for a quick and easy solution. For a low-flush installation, consider providing removable clean-out fittings at each end of the horizontal pipe run to provide easy access should a blockage occur.

A licensed plumber should make the connection with an appropriate flange on top of the composter to accommodate the toilet drain line. One innovative plumber we know used a plastic flow flange that would normally be used to connect a flush toilet to the drain line and to the floor. A union (a threaded plumbing fitting designed to be routinely separated) should serve as a quick disconnect should it be required. Hard connections, such as solvent welding, are too permanent for this purpose.

Back To Top

To install a gravity-drop exhaust pipe with the composter beneath:

1. After carefully measuring, cut a hole in the floor or floors and place the connecting pipe through the hole and into place in the top fitting of the compost container, if it is provided. Remember that the composter can be moved to adjust the location.
2. Use a plumb bob from the center of the hole to locate the inlet to the composter.
3. Using a waterproof sealant such as silicone caulk, seal any gap between the connecting pipe, floor and the top of the tank.
4. Unlike solvent-welded joints, silicone perfects a seal, but allows the connection to be broken if you want to change the location of the composter or pipe in the future.
5. Place the toilet stool atop the connecting pipe.
6. The connecting pipe can be cut to desired height to accommodate your toilet above the floor surface.
7. Position the toilet stool around the pipe – according to the specifications of the toilet stool you have selected.

Note: Some composters might have problems with the impact of the flush water and excrement and feces falling 30 ft (9 m) from the second floor toilet to the composter in the basement. It causes major craters and splashing of the processing material. One could add splash plates to prevent this. Ask the manufacturer for recommendations.

Back To Top

To connect the exhaust pipe:

1. Fasten the top mounting coupling for the vent pipe with screws to the top (or the side) of the composter.
2. Use the flange provided or secure the proper flange for the diameter of the exhaust pipe selected.
3. If there is no flange available, cut a ¾ in. (67 mm) length of the vent pipe and cement it into a coupling. This will leave a short one-in. stub beyond the edge of the coupling.
4. Find the best possible place to make the hole on the top of the composter, if there is none provided, taking into consideration that the pipe should be as straight as possible. Note: The fewer the elbows the better the ventilation.
5. Using the outside diameter of the vent pipe as a guide, draw a circle on the top of the composter where you want the vent pipe to be located.
6. Carefully cut a hole in the composter (unless one exists).
7. Place the stub of the vent pipe in the hole cut into the composter and caulk it thoroughly with silicone to prevent odors from escaping when the system is in use.
8. Insert a union or a no-hub flexible coupling in the line to allow you to remove the composter for service without destroying the exhaust pipe.
9. Install the fan (if required).
10. Cut a hole in the roof straight above the exhaust vent pipe. Use a plumb bob to determine exactly where to cut.
11. Push the ventilation pipe through the hole in the roof and down into a roof boot on the roof. (The roof boot must match your roof pitch and the pipe diameter.)
12. Fasten the rubber flashing gasket both to the ventilation pipe and to the roof with the silicone. This prevents rainwater from seeping into the building.
13. Make sure the exhaust vent pipe is as straight as possible and that all joints are sealed with silicone caulk. In colder climates, insulate the vent pipe to prevent condensation and to improve the draft.
14. If you suspect that wind might cause strain on the pipe where it meets the roof, install a wood stove pipe brace on the roof to prevent damage.
15. Mount a rain cap (or a 90-degree tee) on the exhaust pipe and fasten it with silicone.
16. Cover the outside of the cap or tee coupling with a loose bag of rust-proof fly screen. Fasten it around the vertical pipe with corrosion-resistant fasteners, such as stainless-steel wire or hose clamps.

The UNISEAL™ rubber grommet is a simple, one-piece, and inexpensive way to connect a pipe to a tank. It can be installed in minutes. Use it for pipe diameters from ⅜ in. to 6 in.

Back To Top

The following installation instructions are adapted from those provided by EcoTech, a popular fan choice of composting toilet system owners These instructions are for Model FR-100, designed for high-humidity environments. Available in 115 VAC and 220 VAC or 120 VDC. Use a fan-speed controller.

Select the fan mounting location:

• Allow sufficient access to the fan for service.
• Insert a piece of the exhaust pipe in place of the fan, when you are servicing it or the electric power has been turned off. An in-line fan is an obstruction to natural chimney effect draft, so it should only be in-line when it is meant to be continuously running.
• Mount the fan as close as practical to the termination of the vent pipe. This minimizes the transmission of vibration and motor sounds back to the toilet room.
• To prevent bathroom odors, ensure that there are no competing demands for air, such as fireplaces or bathroom exhaust fans, and open windows on the side of the building opposite the direction from which the prevailing wind blows. If necessary, cut one or two inches off the bottom of the bathroom door to supply make-up air to the stool
• Using wood screws, attach the mounting bracket for the fan motor to a support beam at the selected location. We recommend vertical mounting to reduce condensation buildup.

However, if horizontal installation is necessary, either wrap insulation around the fan or drill a ¼ in. (6.35 mm) hole in the bottom of the housing (along with a threaded insert and drain tubing), allowing condensation to drain out of the fan motor housing.

Note: Step 2 and Step 3 might be reversed.

1. Using sheet metal screws, attach the fan to the mounting bracket. Caution: Do not over tighten any rubber vibration isolation pads or grommets provided with the brackets to prevent the transmission of sound through the structure. Also take care not to strip the plastic housing on the fan.
   • Ensure that direction of airflow is up the exhaust pipe to the roof from the composter
   • Although sheet metal screws are self-tapping, we recommend that you drill pilot holes – no larger than 3/32 in.
2. Connect 4 in. (101.6 mm) ID vent pipe (drain, waste, and vent pipe recommended) to the inlet and outlet of the fan housing, using quick disconnect rubber couplings, such as Fernco flexible couplings. While the worm clamps on the couplings should be snug, take care not to over tighten (60 lb or 27 kg of torque maximum).

Back To Top

Electrical installation work and electrical wiring must be done by qualified persons in accordance with all applicable codes and standards.

Do not connect the power supply until the fan is completely installed. Make sure electrical service to the fan is locked in the OFF position.

While we recommend that the fan be left running at all times, choose a fan suitable for fan speed control use. Pulling too much air through the composter could cool the process, if the temperatures are below the minimum recommended by the manufacturer. A number of users have found it advantageous to have a wall-mounted fan speed controller near the toilet, so that the fan can be optimally efficient, operated at minimum noise/air velocity and shut off temporarily while it is being serviced.

Caution: The fan can be turned on immediately following service. Never place a switch where it can be reached from a tub or shower.

The incoming electrical service should come through the connector clamp and the knockout on the junction box. The necessary connection must be made in accordance with state electrical codes. You must have a proper ground, unless the fan motor is isolated within a plastic housing, where case grounding is not necessary.

Connections, clamp connector, and terminal box screws must be secured.

Back To Top

If the fan fails to operate, check the following:

• Is the power on?
• Consult the wiring diagram provided by the fan manufacturer to assure proper connection.
• Check the motor lead wiring and incoming supply leads to assure definite contact.

Back To Top

Because fan bearings are usually sealed and provided with an internal lubricating material, no additional lubrication is necessary.

If the fan is turned off and left inoperative for more than 10 days, we recommend that you remove it from the vent pipe and store it in a dry environment. (Install a short section of the vent pipe in the fan’s position in the vent pipe.) When do I put the fan back in place

Back To Top

To install a leachate drain line:

1. Using clamps, fasten a flexible transparent drain hose (if your plumbing code approves this design) between the composter’s leachate drain fitting and the drain pipe or leachate container.
2. The drain hose can function as a leachate-level indicator, if the hose is mounted in a vertical position. Better, have your plumber make a permanent drain with hard pipes, with removal unions that flow to a leachate management system. Caution: Leachate should never reach levels as high as the air intake holes or any non-water tight doors. Leachate can spill out of the unit and cause serious trouble (odor, damage to floors, and health threat, not to mention an unpleasant mess).
3. For non electric models, place the hose in a horizontal position to continuously drain the liquid to a container or an approved soil absorption system. This can also be done on electric models, if the leachate is not evaporating rapidly enough (or to save energy).
4. Make sure all connections are both airtight and watertight. If necessary, use silicone or plastic duct tape to seal joints.
5. Periodically check to see if there is excess leachate that should be emptied.

Back To Top

The exhaust system should be constructed so that a minor vacuum is created in the compost container to draw air into the unit and up the exhaust pipe. Odors might result if this vacuum disappears, if there are loose connections or if an emptying door or toilet seat is left open.

To check air paths:

• Make sure all connections are airtight and watertight.
• If necessary, use silicone as a sealant. Such a vent provides a good air supply and prevents air from being sucked back out of the composter and through the toilet stool, which could produce odors silicone or plastic duct tape to seal joints. The exhaust system should be constructed to seal joints.
• A make-up fresh air supply vent to the wall in the toilet room should be installed below the level of the toilet stool at the floor.

Note: If you install a makeup fresh air supply vent, there should be no other exhaust fans in the same room. The composter itself will suck all odors out of the room, so it replaces the customary bathroom vent fan.

Back To Top

When in Doubt, Rely on Your Plumber for Installation Assistance!

It is impossible to cover all installation issues of specific technologies in this guide, so let us leave you with one major thought: When in doubt, rely on your plumber for installation assistance.

Many composting toilet systems require just installing an exhaust pipe, which carpenters and many homeowners can do. However, for more complicated installations such as those with microflush toilets, a licensed master plumber is the best qualified professional to install your system. No other specialist better understands proper installation of mechanical systems and pipes of any kind. A seasoned plumber has worked within the local and state building codes to solve the most difficult drain and ventilation problems. He or she has negotiated the walls, floors, and roofs of countless buildings to move sanitary effluents and odors safely through the building and to perfect the necessary exhaust and makeup air-supply system.

Many plumbers might be unfamiliar with the terms “composting toilet system’ or “graywater system,” but they do understand moving air in and out of any unit process and the drainage or pumping of liquids (leachate or graywater). Give the plumber your engineering documents, plans, specifications, and installation and operation manuals. Be sure to refer to specific approval documents or applicable state code sections.

Back To Top

As with regulators, some plumbers are more open to these technologies than others. Some might even tell you that certain things cannot be done (because they have not done them before). If that is the case, your options are to either educate the plumber or find another. Have them call our toll-free phone line, (855) 864-5980, for assistance.

For those plumbers who still consider composting toilet systems a funky technology, let them know that the Commonwealth of Massachusetts has included composting systems within its State Plumbing Code and requires that licensed plumbers install plumbing board approved composting toilets just as they do water closets (their term for flush toilets).

If you want your plumbing contractor to bid the installation job competitively, you will probably need a plumbing specification to furnish to each of the bidding companies.

Back To Top

If you cannot find a plumber to do the installation and want it to be installed according to best plumbing and mechanical practices, you could go to your library and browse through the Uniform Plumbing Code (UPC) published by the International Association of Plumbing and Mechanical Officials. The UPC has been adopted by many states in the United States and even such faraway places as the Republic of Palau in the South Pacific. Although the code itself is instructive, the illustrated Training Manual is rich with information and provides pictures and diagrams to illustrate all plumbing work, including the exhaust venting, drainage, and piping requirement that would apply to a composter installation.

Many installation considerations are the same as those for hot water heaters, furnaces, and boilers. That is because many fundamental issues are the same, such as location, support, length, pitch, rise, and clearance of pipes and vent components, methods of supplying make-up air, distances of the access opening above grade (18 in. or 457 mm, for example), seismic bracing, roof flashing techniques, use of flexible pipe, unions, and where the end of the exhaust pipe with a vent cap should be relative to open windows and so forth.

Back To Top