Compost toilet: function & instructions for building it yourself

Compost toilets do not use water and are kind to the environment. With our tips you can build a compost toilet yourself or learn more about it.

The compost toilet - how gladly it is dismissed as a crude idea of ​​the ecological movement and just accepted as a vacation or allotment garden alternative. But hardly anyone knows that the composting toilet was in the 19th century. Century developed parallel to the water closet. Modern compost toilets are also hygienic and can look just as appealing as a water closet. The following article deals with the structure, function and use of composting toilets, we also give you brief instructions for self-assembly and introduce some manufacturers.

Composting toilet: what is it?

The compost toilet - also called dry toilet or humus toilet - is usually operated completely without water. The goal is always to return human remains to the nutrient cycle, because these contain valuable plant nutrients that can be used as fertilizers and compostable. This is where humus toilets differ from chemical toilets or plum toilets, because in these models human feces are disposed of without being used. The idea of ​​the compost toilet is ecologically and economically very sensible: Instead of first contaminating our water cycle with excrement and then To clean in wastewater treatment plants, which is time-consuming and laborious, could constantly separate the nutrient and water cycle with the help of composting toilets stay. In addition, there is no need for the complex - and in some locations impossible - connection to the sewage system. For this very reason, in Scandinavia people have relied on the compost toilet in rocky, water-based and lonely locations for decades.

Tip: The history of the compost toilet already includes several chapters: The British pastor Henry Moule invented and patented the so-called earth toilet as early as 1860, in the Victorian era. For a long time, separating toilets were also operated in many German cities - the urine was drained out where it hit a so-called clay wall. This absorbed the liquid and after the evaporation of the water, crystallized calcium nitrate (calcium nitrate) remained. From the so-called saltpeter, this was regularly removed and profitable to fertilizer manufacturers or ammunition manufacturers sold - because converted to potassium nitrate it was used in the production of Gunpowder. Here is a video showing the Labor of the saltpeter introduces.

Summary: what is a composting toilet?

• A compost toilet is operated without water, which is why it is also called a dry toilet
• The water and nutrient cycle should remain separate from the start
• The excrement is then not disposed of, but used
• Reason for use can be an ecological claim, a lack of connection to the sewer system or the desire to save water

Composting toilet: structure and function

Compost toilets are divided into two different categories - the "collection toilets" and the "dry separation toilets". Like every toilet, they naturally have a seat, glasses and a lid. Unlike toilets, they also have an exhaust air system. This ensures good ventilation of the compost and, via a suction effect - similar to the chimney chimney - for good air in the compost toilet. The use of so-called structural material is also important in any case. Bark mulch, straw or wood chips - natural materials with a wide C / N ratio, i.e. a wide carbon to nitrogen ratio - should soak up excess liquid, loosen the compost and become a carbon source for the composting microorganisms Offer. If you want to read exactly what the C / N ratio and carbon is all about, we can provide you with this special article Humus economy recommend.

The conventional compost toilet or "collection toilet"

In this model, solid and liquid are not separated from the start, but are collected together in a container. Depending on the design, the next steps are different:

1. The container is filled with solid and liquid and then emptied - this is often solved by removing a compostable sack. Everything can then be composted together in a composter.
2. There is a composter under the toilet seat, in which solid feces are composted. Liquid seeps down, is discharged and drained into the sewer system or, in a highly diluted form, is used as liquid fertilizer. The composter is gradually emptied via the removal flap, fresh and finished compost can be removed.
3. Solid and liquid are fed into a combination tank. Both are then kept separately until they are finally emptied.

The compost toilet with urine separation or "dry separation toilet" (TTC):

With the dry separation toilet, urine and excrement are collected separately from the start. The urine is either drained into the sewage system or collected in a canister and used as a liquid fertilizer in a highly diluted form. The solid components, on the other hand, are either composted directly in a container located under the dry separation toilet or collected dry and regularly brought to the composter. A flap can block the view of the composter from above.

How do you use a composting toilet?

How a composting toilet is used is probably something everyone can think of for themselves. But the operation of a composting toilet also includes other aspects:

• The "sprinkling" with bark mulch, bark chaff or wood chips
• Possibly rinsing the urine separator clean with a little water
• Emptying the urine can at regular intervals (on most models) - depending on the volume of the can and the number of users
• The removal of the solid part - either for composting or as finished compost - depending on the model

Tip: It is actually absurd to dispose of the urine completely unused. As this contains large amounts of nitrogen and other plant nutrients, it is suitable as a fertilizer. More about the pros and cons of Urine fertilization can be read here.

Composting toilet in the house, on the boat, while camping?

Compost toilets can be used in a variety of ways. We have compiled the different places for that special quiet place for you below.

Composting toilet in the house

If you want to install a composting toilet in your home, a dry separation toilet is a good choice. Because a toilet with a directly connected composting facility would mean that a large-volume composter would have to be installed permanently in the house and under the quiet place. Since a toilet in the house should also blend in with the design of the bathroom, building it yourself is the rule. Construction kits are used here, which form the functional core of the toilet. The scope of such a set can vary. All around you can then design the toilet according to your own wishes. Here you can find out more about the Construction of a composting toilet at the permanent residence and read about the kits used here.

Composting toilet in the mobile home

A compost toilet can also be operated in a mobile home or on board a ship. Again, the dry toilet is recommended, because separating the urine significantly extends the emptying interval. Also, unpleasant smells only develop when urine and excrement come together. If a trip lasts longer than three weeks or if there are more people on board, the sack with the dry excrement can be disposed of with residual or organic waste. If one cannot be found either, in an extreme emergency it is possible to bury the sack so that nature can take care of its recycling. Liquids must be collected and disposed of when the opportunity arises.

Compost toilet in the allotment garden and at the summer house

If it is planned to set up the toilet in a separate toilet block, composting can be connected directly to a collective toilet. To do this, the toilet must be high enough so that there is enough space underneath for a composter. However, such a dimensioning is usually not necessary at all. Small to medium-sized, combined models are available for purchase and only need to be installed in an existing house.

Legal requirements for the composting toilet

The operation of composting toilets in Germany is in legal gray areas in many areas. While the own use in the private ornamental garden is legally unproblematic, there are no suitable guidelines for communal gardens - for example of multi-family houses. The spreading of human excrement is prohibited on commercial horticultural or agricultural areas. However, if they have been composted at a recycling center, they are converted into hygienic compost and can be used.

After all, pathogens that are dangerous to humans can be found in our legacies. If they are to be used on areas that are used for food production, they must first be "sanitized". Hygienization through composting or pasteurization can be used for this. According to the World Health Organization (WHO), the former should last at least two years, the latter can be carried out within about two hours in a sufficiently dimensioned oven.

It can also be important whether a building application has to be submitted for the construction of a free-standing, stationary composting toilet. You should definitely clarify this before setting up. Incidentally, the composting plants required in Germany do not require a permit up to a daily throughput of ten tons.

Build a compost toilet yourself

Depending on where you want to set up a composting toilet, the models presented above are better or worse. Basically, a higher level of comfort or aesthetic demands always requires self-work, because almost all of them Composting toilets are made entirely of plastic and are more of a functional design held. If you are toying with the idea of ​​building a composting toilet yourself, we recommend using kits for the basic elements. The next section provides an overview of the steps you can take when building your own composting toilet. In this case we are assuming the use of a Separett Privy model. The result is a dry-separate toilet. Please note, however, that a wall breakthrough is required to install an exhaust air pipe. In contrast, very small toilets can do without ventilation.

Instructions for building a composting toilet yourself

What you need:

• Separett Privy kit (e.g. Separett Privy 500)
• A bucket for the solid, a canister with a lid for the liquid
• Building material and tools for base cabinet and cover plate. In these instructions we assume a substructure made of wood. Of course, other building materials are also possible
• Pipe with a diameter of at least 75 mm for installing the exhaust air, which must lead out of the room to the outside. Eventually bends, gaskets and pipe lubricants to make this happen
• At the latest for the first emptying you need a composter or at least an organic or residual waste bin

We have compiled the various work steps for you below:

1. It all starts with the construction of a base cabinet in which the two collecting containers for solid and liquid will later have space. Build at a height that allows you to sit comfortably. Beveled or round designs can also increase seating comfort. If the collecting bins are very high, it may be necessary to step at a heightened height to put the feet down. It is also important to install a lockable door behind which the containers and other toilet utensils can be hidden.
2. Then the toilet seat is inserted into the cover plate of the base unit. To do this, simply saw in a suitable lock and then insert the seat - if possible using foam sealing tape. Also note the later seating position here: especially for smaller users, the seat should be as far forward as possible on the edge. Seal the seat all around with silicone.
3. It continues with the installation of the exhaust pipe. For this purpose, a suitable hole is also sawn in the cover plate or the rear wall, the pipe is inserted up to the position of the collecting container and fixed. The exhaust air pipe is now extended to the wall breakthrough with bends and further pipes. The outside must be covered with a rain cover. The pipe is fixed with mounting clamps and sealed at the entrance to the base cabinet. Of course, you should also make the wall penetration tight and insulated. Insulating the entire exhaust duct can involve hiding it behind a panel and prevents the duct from cooling the entire room with outside air.
4. Now position the solid container under the toilet seat. This is lined with a compostable bag. The urine separator hose must be placed in a canister. Here, too, you should pay attention to the tightness: It is best to insert the hose through a hole in the lid. A second lid without a hole can also be very useful for transporting the canister.
5. Your compost toilet is now almost ready for use. We recommend that you oil or paint the substructure in a water-resistant manner in order to make regular cleaning pleasant. Of course, you also need a container for structural material and a small shovel or trowel to sprinkle on.

Rent a compost toilet

Are you planning an event and need toilets? In addition to the Dixie, you also have the option of renting composting toilets.

Eco toilets has several models to offer: from very small to very large and comfortable. In any case, the large models no longer look at all like the hippie or ecological movement and offer everything you need for a "pleasant urgency".

the Ökolocus GmbH also offers the long-term rental of a locus, with almost no limits to the location should be set: Thanks to the modular principle, even the most hidden corners can be used as "places" to serve.

That Kompotoi company carries out an all-round approach in the area of ​​compost toilets: not just mobile toilets, but also the entire planning and Implementation of individual, stationary compost toilets in single or multi-family houses, alpine huts or holiday homes they offer.

In addition to these three providers, there are many more who are sure to be happy to equip your summer party, tent camp or wedding with sustainable and fragrant toilets.

Dispose of compost from composting toilet

As mentioned in the section on legal issues, it is safe to use composted excrement in the ornamental garden. If you have any tips for that proper composting you can find them here. Before spreading in the kitchen garden, however, composting for two years or two-hour pasteurization at 70 ° C is necessary. You can apply diluted urine or drain it into the sewage system.

If you do not want to use your own leftovers yourself, you can also dispose of them in the organic waste bin. Your ecological advantage is still enormous and further processing at the recycling yard closes the nutrient cycle. Incidentally, the hot rotting guarantees complete sanitation so that the transmission of diseases is excluded. Perhaps on a future stroll through the market you will come across vegetables that were grown with the compost of your manure.

Have you heard of the compost trend Bokashi heard? We present you the space-saving alternative to the compost heap.