Dry toilets, toilets without water
Human excrement is not a usual environmental issue. In fact, when in the nineteenth century began to implement (after a patent by Thomas Crapper of 1857 that improved a well-known but little used before it) the WC ( water closet ), the toilet with water or toilet, this ingenuity improved the hygiene in the cities, but left rivers and streams in ruins.
Swiss Madison St Tropez Wall Hung Toilet Bowl Dual Flush Wall Mount (Soft Closing Quick Release Seat Included)
The treatment of faecal waters for environmental reasons will not be implemented in Europe before the mid-twentieth century and in Spain it will not be until the eighties. The fact is that the toilet with water as an invention left without research another invention coetanium, the treatment of human faeces and urines in dry or composted.
How sad it is to use clean water to turn it into putrid black water when more than a century and a half ago the dry earth closet was invented, hardly anyone knows. The current custom is that urine and feces, along with large amounts of water, go down the toilet and are pumped into water treatment systems where the organic matter is devoured by bacteria stimulated by the injection of large amounts of air into the water. The whole process is expensive.
The composted human excrement is not only a fertilizer for the earth but can also become an energy source. In the first case, the composting of human faeces and their use as fertilizer suffices that this has rested for about two years to completely eliminate any pathogenic organism evacuated in the faeces. The biogas coming from the methanisation of human excrement is a reality hardly considered, although this process in addition to obtaining energy also produces fertilizer.
The world of so-called dry toilets or composters is more a curiosity for reports than a daily reality, even so, some families, owners, businessmen, etc. They have opted for this dry technology of human waste. We have the technology so that in the treatment of human feces we put something more intelligence than simply dissolve our droppings and urination in water.
More than a third of the world's population does not have access to such a basic innovation as a sewage system, consisting of a toilet to evacuate and subsequently treat excreta and urine, thus preventing infections and environmental contamination. Black water, as the waters are called with dissolved faecal waste, becomes the main focus of epidemics in urban areas in developing countries. Dry toilets or composters are a solution.
Vignettes of the book The Humanure Handbook , an obligatory reference for those interested in the composting of human excrements, together with the toilet bowl of a sanitary compost of self-construction type "Clivus Multrum".
The history of the earth closet
Human excrement is a source of nutrients just like horse feces or cow dung. The only problem is that just excreted, human feces can be loaded with pathogenic organisms. Therefore, both animal excrement and human feces must be composted to hygienize them.
The first evidence of the connection between certain collective epidemics and human feces did not occur until the late eighteenth century. Towards 1850 the English Reverend Henry Moule (1801-1880) devised the toilet with earth or dry earth closet in response to the water closets that dissolved human faeces with water but according to many detractors of the time were precisely the cause of epidemics such as anger. Moule believed that if the earth closet had been implemented massively many epidemics would have been saved and the health of everyone would have been improved.
In 1860. Henry Moule, together with James Bannehr, considering that the Water closet was a mistake, he patented a dry toilet that soon after began to be manufactured. There was no lack of reason for these visionaries since the earth close t mixing the human excrement with earth, ashes or wood sawdust was more hygienic than the sanitary with water. In 1865 the Dorset County School with eighty-three students changed their water closets for earth closets and not only to save the high cost of maintenance with water but also to eradicate the bad odors that occurred in the septic tanks where they accumulated sewage. Also the Indian government implanted at one time the earth closet in hospitals and prisons in some areas. In 1880 Henry Moule tried to convince the British government that the earth closet was the system of the future. Unfortunately, in spite of the hard battle between the liquid and dry toilet system at the beginning of the 20th century, the water closet was imposed as we conceived it.
Henry Moule did not understand the composting process of human excrement despite his invention to treat them. The first composting toilets with two chambers did not develop until the 1930s with devices such as the Clivus Multrum by the Swedish engineer Rikart Lindstrom developed in 1939 to prevent pollution of the Baltic Sea. Later, towards the Eighties, a provision of the Swedish government prohibiting the septic tanks in the dispersed houses located in the natural places encouraged the commercialization of composting toilets in that country. This also allowed the emergence of commercial models based on plastic fiber as we know today, such as BioLet, Sun-Mars, Clivus, etc.
In China decades ago human feces were composted to be used as fertilizer. The need to avoid polluting the waters was the first goal that encouraged human stool composting enthusiasts. Today, in addition to this exposed reason is added another no less powerful that is to avoid the contamination caused in the manufacture and application of chemical fertilizers. There is a clear certainty that the composted nutrients from human manure could save up to 15% of synthetic fertilizers. This highlights the importance of compost toilets as an essential device in the design of the sustainable city.
In our country there are still too many taboos regarding human feces. Remember that one of the first warnings made to children is: "poop, do not touch." It is evident that from an ecological point of view, the dissolution of feces prevents us from having a useful resource for agriculture and to improve the soil quality of the soil. Currently, various models of composting toilets or dry treatment of human feces are commercialized throughout the world. All these systems achieve that the faeces are composted, that is to say, that they undergo an aerobic degradation process in which a succession of microorganisms not only mineralizes the human organic matter, but also pasteurizes and destroys all the pathogenic microorganisms that we excrete when defecating. Although they are practical in everyday use, the current toilets with water that enjoy the water closet type are an environmental irrationality, because to treat the residue of the digestion of the food that the land has given us, we first contaminate the water and then consume energy to clean it up
The composting toilets with external storage
One of the most extended models or variants of the same is the toilet Clivus Multrum type. The main characteristic of this is that it needs an area outside the house, where the compost is stored. Until recently the typical clivus multrum was self-constructed. Today there are a couple of manufacturers who have designed a separative and compact toilet that separates urine from feces based on a model by the Swedish scientist Matts Wolgast. This type of toilet starts from an old idea that is the use of urine in the fertilization cycle (see a detailed monograph -pdf of 4 Mb- in English about it).
Among the models that exist in the European market of separative toilets we will comment the Ecodry by Wostman , the one of the German firm Separret with its model Villa and finally, the one of the French firm Ecodomeo .
In the Ecodry dry toilet, the separation of urine makes it possible to obtain a completely odorless residue and use the urine as fertilizer. The stool is collected in a container under the floor. The fecal matter falls into a container, where it evaporates and dries. A fan in the container so that this residue dries and bacteria and viruses are eliminated. A deposit below the 80-100 liter toilet allows family waste to be stored for about three months. When it is full, the stools are usually dry enough and weigh only 10-20 kilograms. Its operation is very simple for the user as shown in his manual . The deposit must be ventilated. There is the possibility of connecting a water tap to it if necessary. The Separret is similar in operation.
Wostman 's Ecodry porcelain dry toilet with separative system of urine and feces, one of the most affordable systems.
In the dry toilet of the firm Ecodomeo this has a more sophisticated mechanism because at the bottom of the cup there is a conveyor belt driven by a pedal, which makes a slight slope. The urine slides to the front, where it is collected by the drain and stored in a tank, then mixed with ten parts of water per unit of urine, this can be used as fertilizer. The faeces remain on the tape and, together with the paper, they are transported to the composting warehouse located outside. This toilet is also plugged although the consumption of the tape and the fan is minimal, about 15 Wh. By separating the urine from the fecal material, it prevents a doughy mass from being created and that does not produce the characteristic bad odor of the mixture of faeces and urine. In addition, since it is well aerated, fecal matter can not evolve into an anaerobic process that is responsible for causing bad odors.
Vater dry type separative Ecodomeo and its side the installation scheme of the same with the storage chamber.
The sanitary composter par excellence
Undoubtedly, one of the most interesting toilets for collective health facilities is that of Clivus Multrum. This offers dry toilets that include storage tanks from 650 liters capacity. It is a sanitary composter that follows the design scheme of Lindstrom, with a camera where urine, feces and organic waste produced by the family are processed together. It consists of a composting chamber with a sloping floor, air ducts and, at the lower end, a storage area. A tube connects the pedestal toilet bowl to the reservoir receptacle. Often also has a special mouth to pour kitchen waste. This sanitary composter system therefore includes the permanent air circulation thanks to the natural current that originates in the air ducts of the storage chamber of the material to be composted. The air comes out of the vent of a small chimney.
Diagram of operation of a Clivus Multrum toilet, together with two toilet facilities, one of very elaborate and the other more conventional.
Al Clivus Multrum not only reach the faeces and urine, but also the toilet paper. They also recommend adding a handful of sawdust after each service and some models have a hole to pour waste into the same sanitary tank from the kitchen: vegetables and pieces of meat, shells, bones, egg shells, garbage that comes out when sweeping, paper napkins and cut grass (not so cans, glass, plastic or large volumes of liquid, of any kind). Due to the slope of the floor of the Multrum sanitary container deposit, the fresh falling material slides little by little, from the part where it is deposited, to the lower part where it is stored. The composting process decreases the volume of the pile, reducing 90%. Finally, it must be borne in mind that for the installation of the Clivus Multrum toilet, depending on the model, at least it requires a storage space below the bathroom floor (of 1.3 m for the small family model M100).
Biolet, a classic
This composting toilet has the advantage that it does not require installations since the storage tray is incorporated in it. The Biolet includes various models of toilets manufactured in Sweden, a country in which for reasons of legislation has driven the commercialization of this technology. Among its main design advantages we note that it has a secondary lid that does not open unless we lean on the toilet seat. The other characteristic is that it has a heating system with a thermostat that allows the composting chamber to work with the right temperature for the process. Finally, between its peculiar design highlights the rotation platform that separates the stool from the drop point with which the next user can not see not smell anything. The forced ventilation system allows bad odors to go outside, although in general this type of dry toilets hardly smell. Every three weeks the tray is removed with the feces converted into "earth" or humus. The toilet itself is a bit bulky, but very comfortable, although it needs to be plugged into the power grid. A family of three consumes between 30 m 3 and 40 m 3 of water per year for the toilet. If we make calculations in the case of water consumption that we would save to install a dry toilet or composter, we would see that in 15 years it has been amortized. When constructing a new house, one could consider not foreseeing any infrastructure for a water toilet. If the house can not be connected to the sewerage network and it must be poured into a septic tank, the fact of avoiding the maintenance costs of this also reduces the time of amortization of a dry toilet like the Biolet.
The composting cube
Undoubtedly, it is the simplest sanitary composting system that works as a collector of human excrement for later composting. It is widely used in camping and summer homes in the middle of nature where it is not advisable to make septic tanks and there is space available to deposit the collected waste. In this type of toilets it is essential to use sawdust or wood shavings, as in addition to absorbing excreted liquids, it also contributes to facilitate composting. There are a few manufacturers in Europe of which we stand out for their proximity Lecopot , and Ziya, both firms are based in France , a country in which there is a good marketing of these simple dry toilets.
The key to the proper functioning of these composting toilets is the use of vegetable cellulose (sawdust, wood chips, etc.) which inhibits the enzymatic reactions that mineralize the organic matter in the excrement. These reactions are precisely the origin of unpleasant odors. For this reason it is necessary to add vegetable cellulose, especially in the form of wood chips in the excrement in order to block the enzymatic reactions and in this way neutralize the odors. The shavings of wood or sawdust therefore means intervening in the carbon-nitrogen ratio of our excrements, which facilitates aerobic composting in the open air. An important detail: the blocking of enzymatic reactions takes place only if there is moisture, so this type of dry toilets do not separate the urine from the fecal material.
Its operation is thus very simple in this sense. A bag of compostable bioplastic is placed inside the bucket or toilet. At the bottom of this bag a sawdust bed is placed and after each use it is sprinkled again with sawdust. Once the bag is full, it is deposited in a composting container. The maintenance of the toilet is like that of any other. The stainless steel bucket facilitates its sanitization.
On the left two Lecopot models, one of which incorporates the deposit for the sawdust and on the right two models of Ziya, the last one of which made with recycled cardboard available in Label Verte .
This option is recommended for single-family homes or located in natural spaces. It is a minimum maintenance sanitary because it is enough to handle it properly so that the necessary balance is provided for the good progress of the composting process.
Pipis to grow plants
One would think that urine has nothing particular about it. But it is a liquid rich in potassium, one of the nutrients that provide the heart with its ability to regulate blood flow. Our body can not accumulate potassium because in the bloodstream it is a toxin. That is why it is excreted as quickly as it accumulates when ingested with the diet. Urine should not be thrown away, but returned to the nutrient cycle. In times of the Roman Empire, the emperor enjoyed the privilege of collecting the urine of his subjects to use as a cleansing agent.
In the capital of France have already installed several urinals (unfortunately only for use by people of the male) of the company Uritrottoir that combine two very interesting aspects, on the one hand give a different image of the public urinal and another give a new focus on the utilities of urine. His motto "Civiliza los pipís" can not be more direct to give the ethical touch on the problem of peeing incisively on public roads. It is undoubtedly a curious street urinal whose first units have been installed near the Gare de Lyon railway station. Its operation is very simple. The urine is collected in a container filled with straw that can later be composted and returned as fertilizer for urban public green. Each planter can receive up to 500 pipís with a volume of 240 liters. When the tank is full, an alarm is activated which allows the specialized company to collect the straw for composting that is in the tank below. Its promoters, pose it as an alternative to combat the incidents of urine, something very common in certain neighborhoods of many cities. Hopefully in the future there will be a version also for the feminine pee, although at the moment, according to the clothes that the woman uses, she can use the peeing adapter as the Shewee.
Basic tips for composting toilets
In those dry toilets that do not separate the faeces from the urine, a bed of cellulosic material such as wood shavings, sawdust, straw (preferably pitted), hay, dry leaves, crushed branches or even shredded cardboard should be used. In these toilets toilet paper can also be placed inside.
As a complement to the dry sanitary toilet, it is necessary to have a conventional composting container for those used for the composting of garden waste or domestic organic waste. There are many models of composting containers in the garden. The most recommendable are those that have manual rotating hand systems of the material to be composted. In these we can mix both the dry toilet material and household organic waste of the house.
There are no restrictions on the use in gardening or horticulture of composted material extracted from dry toilets as long as the compost has totaled a composting time of two years to eliminate the pathogenic organisms in the feces. In 1979 trials were carried out by the Department of Microbiology of the Norwegian University of Agriculture on problems that could lead to the development of fecal composting of people taking antibiotics. The results showed that this does not lead to a significant or prolonged alteration in the compost, and never, except in cases of massive doses of truth, there is no need to worry about it.
In dry composter-type toilets it is better to use not very large cubes, from 15 to 20 liters is enough and in a family of four this will allow you not to have to remove the material more than every two or three days. It is recommended that the bucket be made of stainless steel, as it is easier to clean, stains less easily and is not impregnated with odors. Galvanized buckets should be avoided because they are quickly attacked by urine and corrode easily. Anyway, we want to remember that on the subject of dry toilets there are good ideas and many options of do it yourself, which are very useful to consider and applicable in certain areas of the planet's impoverished.
Technology for the future
There is no doubt that the technological improvement of the toilet-toilet, toilet, toilet, toilet, or whatever you want to call it is a field that still has possibilities. Suffice it to see the development of the so-called Nano MembranoToilet , a complex ingenuity but with interesting ideas and that its authors have put at their disposal. Currently, research, many of them funded by the Bill & Melinda Gates Foundation work to improve health quality in developing countries seeks:
- - eliminate germs from fecal waste and recover useful resources once sterilized: energy, clean water and nutrients (which can be used as fertilizer or "humanure", "human manure");
- - operate without electrical energy and other than water installations;
- - operate at a cost of less than 0.05 cents per person per day.
