Commercial Composting Toilets

Sun-Mar Composting Toilets
Sun-Mar offers toilets that are quick to install and easy to use with models that require no water and no plumbing. Sun-Mar toilets range from $249 for a toilet (which is combined with Sun-Mar Central Composting Systems, which start from $1,299) to $1,299-1,599 for their complete composting toilets. Sun-Mar composting toilets recycle through decomposition and evaporation. Water content is evaporated and released into the atmosphere through a vent system, the rest of the material composted through natural decomposition.

Sun-Mar toilets use three separate chambers. The drum, the evaporation chamber and the finishing drawer. The drum works to compost waste in a warm and moist environment with the organic material and oxygen needed to promote the work of aerobic microbials (found in the topsoil that is added to the compost) for decomposition. A peat mix is used as a bulking material. You must mix this with the waste by periodically by rotating the drum 4-6 full turns via a handle, which will also ensure aeration of the contents. Turning the drum should be done 3 times a week when the toilet is in use.

Emptying the drum into the finishing drawer is a mater of releasing the drum locker and rotating it backwards when it is 1/2 to 2/3 of the way full. The drum also maintains optimal moisture content for the aerobic microbials. When moisture rises above 60%, liquid is drained into the evaporation chamber through a screen at the bottom of the drum. Sun-Mar ensures moisture content in the drum for composting by not applying direct heat to the compost. Sun-Mar's electric units include a base heater, which they say supports the heat generated by the microbes.

The evaporation tray in Sun-Mar's electric units work with a 110 Volt heating element controlled by a thermostat, heating the floor of the evaporating chamber without drying the compost. In non-electric units, excess liquid is evaporated through passive venting and through overflow drains. The finishing drawer completes the composting process, ensuring the compost is not contaminated with fresh waste and is sanitized. The compost drops into the drawer when the drum is rotated backwards and is surrounded by a stream of drying air to dry it until it is ready for removal. The contents of the drawer should be left to age for 3 to 4 weeks. The drawer should be removed and/or emptied of compost before more compost is deposited from the drum.

Sun-Mar toilets are free of odour. Then environment created in Sun-Mar's toilets promote aerobic decomposition which produces no bad smells, as opposed to anaerobic decomposition. In addition to this, electric models include a fan that draws air in, creating a partial vacuum that ensures no smell escapes the unit. Non-electric models do this through a vent chimney, placed over the evaporating chamber, as is the fan in electric models. They suggest adding peat to the drum at a rate of one cup per person per day.

Rota-Loo
The system of the Rota-Loo requires no water to transport your deposits in the toilet and sits directly below your toilet room. The system is made of polyethylene and contains 6 removable compost bins housed on a turntable. When one bin is full, the turntable is manually rotated so a fresh bin is under the toilet. These bins remain inside the system where the composting process continues until all of the other bins have been filled and it comes full circle, full of humus. You just pull the bin out, empty it and replace it inside the system to be filled again. If all of the bins in the system fill up before the first bin is finished composting, you can remove the bin to a safe place for the composting to finish and put a spare bin in its place within the system.

Each composting bin has a geo-textile filter in the bottom that has a porous rate of around 300 litres/second/square meter and a mesh density of 175 microns, allowing liquids and oxygen to pass through and no solids larger than 0.175mm. This is supposed to assure an aerobic process with minimised smell. You may also add a far to the system to avoid having too high a moisture content if this is a problem. Any odours in the toilet room are said to be taken down the waste chute, due to air being continually pulled through the vent. The air inlet is placed as close to the base of the system as possible with the vent coming off close to the top, allowing for air to pass directly over any liquid drained through the bin to be stored under the base turntable.
Rota-Loos come from a 65cm tall/120cm diameter system that will cater to 4-5 people, designed for holiday homes, to a 95cm tall/120cm diameter system that will cater to up to 8 people and can accommodate 2 pedestal toilets as opposed to 1.

Clivus Multrum
This system comes in many convenient sizes, taking into consideration how many people will be using it, how much space there is for the composting system; ranging from a small system suitable for small homes or holiday houses, to a much larger system suitable for high-traffic public areas. Any but the smallest of these systems can support more than one toilet room if they are located beside each other. If the toilet rooms are located at some distance from each other, however, they will each require their own composting system.

Since aerobic composting requires warmth, additional insulation around the system may be required in areas where the temperature is cooler to ensure that the heat generated by the aerobic microbials is kept inside. This system needs to be placed under the floor of the toilet room, like that of the Rota-Loo. This system allows you to connect two toilets on different floors to one system simply by extending the length of the chute that connects to the toilet on the second floor, so long as the toilet room is located close to the toilet room below it.

The Clivus Multrum uses electricity to run, with a solar power package available to run the fan during daylight hours, or 24 hours. If neither is desired, or available, continuous odourless operation is not guaranteed. A normal 240V power point is required near the fan housing in a weatherproof location, with a 12V transformer plugged into it if a smaller fan is to be used. This system has three fans available to it, from 12V/5Watts (2.5Watts for solar installations) to 240V, used with commercial installations.

You may also use worms with this system, if this is desired. If you are going to add worms to the system, then you need to take special care to ensure adequate moisture, good pH and a balance of carbon/nitrogen, as well as plenty of food.

Envirolet
Envirolet toilets range in cost from $1,450 to $1,995. Models are waterless with or without electricity requirements, with a low-water system that uses 1 pint of water to flush. They offer a self-contained system as well as the style used by the previously mentioned Rota-Loo and Clivus Multrum.

The self-contained system is recommended for use in ground-level homes, or for cottages and cabins. They are constructed of polyethylene plastic and have UV protection, available for 12VCD battery, 120VAC electric, and non-electric. The electric models have a switch control for fans and/or heating systems. These self-contained systems also contain a built-in Rake-Bar and a collecting tray to make emptying the compost easy and a Mulcherator to occasionally assist in the composting process. The non-electric model with service 2 people full-time and 4 people if used as a vacation toilet. The battery operated toilet will service 4-6, while the electric model will service 6-8. They are fitted with a filter drain and require a proper drain site; a vertical vent system. Costs range from $1,450 to $1,650.

The waterless remote system is made from HDPE plastic and is comprised of a toilet with a remote waste treatment center that is installed directly underneath the toilet, below the floor. This system has the highest capacity, servicing up to 10 people per day with occasional guests. The system is ideal for cold-weather use and, like the self-contained system; electric models come with a switch control for fans and/or heating systems. The non-electric model will service 4 people full time and 6 people if used as a vacation toilet. The 12VCD model will service 6-8, and the 120VAC model 8-10 (with occasional guests). These models also require a proper drain site and a vertical vent system. Costs range from $1,795 to $1,995.

The low-water remote system is made of porcelain and comes with the same features as the self-contained systems and the waterless remote systems. Additionally, natural organic products may be added to the treatment center via a service port. This system requires good insulation if used in cold weather and will service the same number of people as the waterless remote models (minus the occasional guests on the 120VAC model, apparently). These systems cost no more than the waterless remote systems, although you have the added cost of the pint of water being flushed down the toilet every time

Cotuit Dry Toilets
Cotuit toilets use a separate urinal to keep the compost bin from becoming anaerobic due to excess liquid. Excess liquid shouldn't be a problem though if you just keep an adequate cover of clean organic material. Generally, you may find the need to add moisture, not reduce it. Their toilets use no mechanical devices to turn the contents of the compost bin. They stress the importance of cleaning all surfaces that come into contact with manure to remove any fly larva, which should only be the composting bin itself in these toilets, lending cotuit one of the highest in terms of toilet management demands.

Cotuit toilets run in two modes:
They maintain that nitrogen conversion into ammonia will be inhibited by the closing of an inner hatch after every use to cut off the supply of air, limit moisture build-up and inhibit insects. They suggest the use of a power vent as well as insecticides or diatomaceous earth once a month to further inhibit insect development in hot weather.
The second mode is one of dehydration through the continuous use of a vent, rendering the end product hard instead of decomposed compost and potentially doubling the capacity of the chamber. Manure coming from their system has a generally mild odour and it is recommended that it is used in an ornamental garden underneath a layer of mulch, keeping it away from possible contact with people or animals.
Another suggestion is to add it with other organic materials to a compost bin, but for all that, you might as well just build yourself a cheap sawdust toilet

Cotuit also maintain that urine is free of pathogens so long as it does not come into contact with feces, which is why it is so important to urinate in a separate area from your composting toilet. Suggesting that this urine is therefore free of all pathogens, they say you can use it straight on your vegetable garden and the vegetables will still be safe to be eaten raw.

Cotuit dry toilet sells for $850 with additional supplies ranging from $5 (for a scoop) to $260 (for a flush toilet interchange vent kit).