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Urine Diverting Toilets (UDTs) work by separating urine and solids at the source. The urine is collected at the front and channeled and the solids fall into a container at the rear of the toilet. It is important to note that a urine diverting toilet does not break down waste, it simply collects it so it can be removed and allowed to decompose in an outdoor compost bin. The urine is channeled into a drain. It does not present an environmental threat as pure urine (from a healthy person) is relatively sterile. Composting toilets (CT) do not separate urine from solids. Nitrogen (from urine) is needed to fuel the composting process. With a composting toilet, bacteria will break down waste and in doing so generate enough heat (up to 70 degrees C) to kill pathogens found in fecal matter – thermophilic composting. Check out this post on composting for more information. Excess fluid from a composting toilet has soaked into the compost pile and is also a mixture of urine and fecal matter. This is called filtrate.

The filtrate can be treated or collected in a container and ideally stored for 6 months before adding to the soil. As for male urination with a UDT, males have to sit down, whereas with a composting toilet they can stand normally. Waterless urinals are an optional extra for both types.

Ability

The great thing about a UDT is that there is no maximum drive capacity. As long as the owner changes the bin to a new one, the toilet can go on and on. Urine is channeled neatly to a drain. Conversely, if a composting toilet is used, there is a maximum capacity, rated in people. The composting process occurs in the unit and lasts about 6 weeks. Therefore, if the amount of material entering the toilet is greater than the amount that the toilet’s bacterial population can process, it will build up in the toilet and take some time to recover. So it’s important not to choose a composting toilet that is below its intended use because with a CT you rely on a biological process to break down the waste for you; see post. But with UDT this is not a concern as all you have to do is replace the container.

Follow-up

The best thing about a composting toilet is that when the compost is removed from the toilet, it is safe to put it under shrubbery or in a flow garden. The thermophilic composting process has eliminated pathogens and is therefore safe.

No further follow-up care is required. There has been little to no unit failure with the UDT. That means you’ll need to flush the UDT more often (every 2-3 weeks) than a CT (every 3-6 months). In addition, the material that comes out of the UDT needs additional composting for 18 months before burial. This composting should be done in a compost bin that is sealed at the base and does not allow rainwater to enter. Therefore, more follow-up care is required with the UDT, which is up to the owner to manage it properly. Some local authorities view this aspect of UDT as a negative, as there is a potential for human error and faecal matter coming into contact with the water table.

Price

Examples of urine diverting toilets are Separett Privy 500 and 501, Separett Villa and Biolan Separating dry toilet. Generally speaking, since UDTs do less for you, they are easier to design and manufacture, they are cheaper than CTs (Sun Mar and Biolan Eco range) which are more well designed and do more for the owner.

I hope this explains this problem a bit. Please contact us for more information.