TECHNICAL FIELD

The present invention relates to a device and method for treating human waste, the device, a "dry" waste-sanitization device, comprises a urine handling unit that minimizes water usage and urine volume, while maintaining the nutrient value of the urine such that it may be used as a fertilizer component.

BACKGROUND

The managing and treatment of human waste in the form of urine and faeces is a technical field of increasing importance. In most developed countries, toilets consuming large quantities of water are used to flush human waste through a sewer system to treatment plants, where the waste is captured and the water purified before releasing the water into adjacent streams or lakes. This manner of handling human waste has significant drawbacks, among them the consumption of very large quantities of water and the difficulties in capturing waste substances so that the water released from the treatment plants are clean enough to avoid overfertilization of streams, lakes and land surrounding them. Although the methods for handling urine and faeces are well-developed and reliable there is insufficient knowledge of how to handle additional substances such as drugs and other chemicals that are released from humans through their urine. As a result, substances such as antibiotics, hormones or narcotics may still be present in the water released from treatment plants and may pose a risk to organisms such as fish. If the water released from the treatment plants is able to penetrate lakes or reservoirs used as fresh water supply for cities there is also a risk that such substances may be present in drinking water.

In some parts of the world, the problem is instead that sanitary solutions such as toilets are unreliable or not present at all. This results in the need to handle and transport human waste without the aid of sewers and also poses a health risk both to persons responsible for such handling and to persons who live without access to satisfactory toilets.

A present and future need, for the purpose of recycling and environmental care, is to be able to extract the nutrients from said human waste.

There are some known prior art toilets that attempt to resolve these problems through providing toilets that require low amounts of water or that attempt to handle human waste without using water at all. However, there are no known solutions that provide a safe and convenient toilet, wasteseparating toilet or source-separating sanitation solutions that minimizes water consumption and odor, avoids human handling of the waste and that maintains the nutritional value in the waste.

In the literature there is only one known example of urine separating anhydrous toilet with mechanical transport of urine found, and it is on the International Space Station ISS. This is system is very complicated, and works with a vacuum since in weightlessness you have to have a negative pressure to suck the liquid into the form of floating bubbles. This requires rigid tubing that do not collapse under negative pressure.

Translating this technology to an affordable and efficient urine separating toilet or sanitation system has not been suggested or shown. Given the space restrictions, the tubing used needs to be flexible to follow the topography and be easy to install. On example may be flexible plastic tubing with rills, similar to tubing of a vacuum cleaner tubing. However, urine can accumulate and become stagnant in the rills which leads to biofilm and precipitates that cause blockages. Moreover, said tubing are very expensive. Other examples of tubing possible tubing are tubing of hard polyethylene, such as PEM pipes. These are however difficult to handle and are also expensive. Soft tubing with smaller diameters, such as garden tubing, are easier to employ and cheaper, but they increase the risk of blockage.

To be able avoid blockage while using flexible tubing of small diameter, it is thus necessary to avoid formation of biofilm that contributes to mineralization and precipitation. Mineralization in the urine is a big problem. Urine contains a variety of minerals that in themselves, (for example, magnesium ammonium phosphate), or together with minerals in water form precipitates (for example, lime in water can form calcium phosphate with urine). A number of organisms can also form hard plaques.

Sanitization or cleaning chemicals may be added, but if not correctly dosed, they may themselves cause precipitates and blockage. Moreover, commonly used sanitization chemicals may destroy the nutrient ability of the urine.

The toilets mentioned above handle the smell of the faeces and urine it receives with different with complicated and expensive techniques or a combination of strong chemicals or a large quantity of milder chemicals. There is therefore a need for an improved source-separating sanitation solution that solves these problems in a convenient, reliable, cost-effective way, and environmentally friendly solution.

Summary

The object of the present invention is to eliminate or at least to minimize the problems discussed above. This is achieved by a device and method for handling human waste, in particular relating to treatment of urine, according to the appended independent claims, and also, to software and hardware for performing the method.

The present invention relates in particular to "dry" or "anhydrous" waste-sorting sanitization devices or toilets, even if the present technology also can be utilized in regular wc. Combustion and compost toilets are existing examples of "dry" or "anhydrous" toilets. In waste-sorting dry toilets, the faeces end up in a container placed directly below the user when they sit in the toilet. Furthermore, there is a urine separating seat with a separate bowl for the urine.

Some particular features of the present invention are that it separates urine and faeces, stabilizes the urine by addition of a urine-stabilizing substance making it storable without odor and used for fertilizer production, provides superior mixing of urine-stabilizing substance and urine which minimizes the required amount of substance, and transporting the urine, and optionally against gravitation, for higher level storage. The technical features providing these advantages will be described more in detail below.

The present inventors have developed an integrated source-sorting anhydrous toilet. The present invention focuses on the handling of urine, and is designed for a small environmental footprint and the purpose of using the rest products as fertilizers. While avoiding smell and precipitations that may block the pipes or tubing of the toilet, it only requires mild or small quantities of chemicals. The device is fitted with a urine mixing and transportation pump that can be placed in a toilet seat under the urine separating bowl. Urine is moved through narrow flexible tubing, while avoiding precipitation and biofilm growth in said tubing by being able to dose and mix urine-stabilizing substances in the right amount and at the right time. In addition to preventing bad smell, the combination of said appropriate amount of urine-stabilizing substance, mixing, and automatic emptying of the urine in the urine buffer tank. The mild chemical of chemistry prevents loss of nitrogen (urease in urine hydrolyses urea to form volatile ammonia), which maintains the nutritional value of urine and makes it usable as fertilizer. In addition, the simple and compact sanitation device or toilet, having urine treatment integrated in the toilet module itself, features a minimum of tubing, pumps and valves, thus greatly reducing the risk of precipitation and biofilm formation and blockage, and the need for maintenance. This device may be combined with other technology developed by the applicant that also handles the faeces in an efficient and safe manner, see for example WO/2022/071865.

Although urine is an excellent fertilizer and a critical part of a sustainable future, recycling does not take place on a larger scale. The main reason is that most waste-sorting systems are based on free fall, where pipes and storage tanks must be placed under the toilet. If the waste-sorting toilets are flushed with water, you get a mix of water and faeces that are difficult to purify. The urine ends up in its own container placed under the toilet. If the container is small, it must be emptied manually at high frequency, which becomes labor-intensive and unpleasant as urine smells badly. If they are made larger, the investments will be significant because the urine container must be buried, or the property must have a basement to be able to install tanks under the toilet. Only users which are very confident about the benefits of this will invest in such solutions.

The present inventors have discovered that if you move the urine using a pump, and optionally against gravity, in flexible and thin tubing, such as water pipes or garden hoses, such waste-sorting toilets are easier to install and maintain. This would reduce costs and work, which would make recycling easier, both in houses and residential areas, but also in motorhomes, boats, temporary toilets and more.

Such a technical solution would lead to a number of advantages. Dry waste-sorting toilets could be easily placed in basements and the urine may then be pumped to ground level. A number of toilets can be connected to a "microgrid", where urine is led to a common process unit. Anhydrous toilets can be installed in Attefallshus (small houses of less than 30 square meters detached from a main house) and the urine is led to existing sewers.

If more waste-sorting toilet systems are introduced and especially anhydrous ones, water and energy consumption can be reduced, and as well as pathogen emissions and eutrophication, the load on treatment plants and the use of environmentally unfriendly mineral fertilizers.

Cost-effective water and waste solutions may also be affordable for tubing in developing countries are currently lacking functioning sanitation solutions. Especially, if these can be powered directly by solar heat or solar electricity. In the present invention, urine and faeces are separated. This greatly facilitates the handling of faeces as these are disease-causing and unpleasant to handle. An energy efficient waste-sorting anhydrous toilet, with good handling of faeces and urine, which enables the transport of urine in narrow flexible tubing, thus increases the availability of sustainable water and waste solutions and is thus highly desirable.

According to the first aspect, there is provided a device for treating human waste 1 comprising: a container for receiving urine 2 which is in open connection with the buffer tank; a buffer tank for receiving and storing urine 3, wherein the container 2 is in open connection with the buffer tank 3; and a pump (4) for mixing and transporting urine and added urine-stabilizing substance, which is in open connection with the buffer tank, and wherein the pump is adapted to create turbulence in the buffer tank and pump chamber; wherein the device 1 is designed to receive urine into the container 2 and direct this to the buffer tank 3 and further down into the pump chamber of the pump 4, and when operating the pump, the urine and the urine-stabilizing substance are mixed into the buffer tank and the pump chamber with the help of the turbulence that the pump creates in these.

According to the second aspect, there is provided a method of treating human waste that comprises: to provide a device as described in the first aspect, as well as a urine-stabilizing substance; wherein the method comprises the steps of: receiving urine in the container 2, when a user uses the device 1, and leading it, preferably by free fall, to the buffer tank 3 and further down into the chamber of the pump 4, while putting the urine-stabilizing substance into contact with the urine; and mixing the urine and the urine-stabilizing substance, by operating the pump, in the buffer tank and the pump chamber using the turbulence that the pump creates in these.

In further aspects of the invention, there is provided: a software a data processing system comprising means for carrying out the method of any of the claims, a computer program product comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method of any of claims, and a computer-readable storage medium comprising instructions which, when executed by a computer, cause the computer to carry out the method of any of claims. DRAWINGS

The invention will now be described in more detail with reference to the appended drawings, wherein:

Figure 1 discloses a waste-sorting toilet according to the present invention.

Figure 2 discloses an embodiment of the waste-sorting toilet according to the present invention with a urine separating bowl, a urine buffer tank, a pump integrated into the bottom of the buffer tank, an elevated urine storage tank and evaporation of stabilized urine, and how the pump and buffer tank improves the mixing of urine and added urine stabilizing substance

Figure 3 discloses a flow chart of the basic steps of the method of operation of the waste-sorting toilet according to the present invention

Detailed description

In a first aspect, there is provided a device 1 for the treatment of human waste comprising a container 1 for receiving urine, a buffer tank 3 for receiving and storing urine (said container and buffer tank being in open connection) and a pump 4, preferably an impeller pump or centrifugal pump, having a brushless DC motor, more preferably an impeller pump with a non-flexible impeller having a brushless DC motor, for mixing and transporting urine and urine-stabilizing substance (added to the urine in the device), and which pump has a chamber in open connection with the buffer tank, wherein the device 1 is designed such that when urine is received in the container 2 it is passed to the buffer tank 3, preferably by free fall, and further down into the pump chamber 4, and then, when operating the pump, the urine-stabilizing substance is put into contact with the urine, the urine and the urine-stabilizing substance are mixed in the buffer tank and pump chamber by the turbulence that the pump creates in them.

6

SUBSTITUTE SHEET (Rule 26) The container and buffer tank are in open connection with each other. In one embodiment, these are in constant open connection. In another embodiment, they are in open connection but a valve or check valve is located between them.

The floor of the container for receiving urine (2) and the buffer tank (3) is preferably slanting towards an outlet of said container or tank to fully empty the container and tank, thus preventing bad smell, salt precipitation or biofilm formation. The slanting should typically be at least 2-3 degrees. In one embodiment, the outlet if the urine container features a sieve to catch small particles such as sand, hair, or other small objects that may fall down into said container when using the toilet.

The present inventors have during the development of the present invention studied and tried a number of pumps and technologies. Below is a summary of what has been concluded about the previous technology, and how this led to the discovery of the present technology.

In the toilet of the space station ISS as mentioned above, the pump in vacuum system is not integrated into the toilet. The vacuum pump must be located at the final tank. This poses a number of problems. The tank must withstand negative pressure and be specially adapted to the pump to which the urine is sucked, which requires complicated signal and power lines between the tank and the toilet, which complicates the construction and increases production cost. Vacuum pumps separate gas and liquid with the result that ammonia from the urine and bad odor may escape the system. Vacuum pumps are expensive and complex, and it takes time to build up a vacuum when large amounts of air are to be evacuated. This puts great demands on the size of the buffer tank and the signaling system; it becomes more difficult to scale up the system due to the vacuum requires more signal and sensor technology, excavating pumps, etc. Alternatively, the system has a vacuum "on demand", i.e., is already operating under pressure. But then complicated electromechanical valves are required for the vacuum to reach the urine. The technology is thus not feasible for non- costly toilet and easily manageable systems for everyone.

If you use pumps with positive pressure instead of vacuum pumps, this entails a number of other problems. Mainly that these are often powered by DC motor with commutator. Where the rotor and stator are in direct contact with each other. If such a pump pumps without liquid, i.e., dry, then it melts the gaskets that seal the shaft that transfers power from the motor to the pump chamber. Which means that liquid penetrates the engine and destroys it. This is especially the case, if the pump handles urine that is salty and corrosive. Furthermore, the pump must be able to pump urine, other bodily fluids such as menstrual blood, discharge and particles. In toilet systems with mixed waste, the pumps used are often based on the principle of a flexible impeller. The disadvantage is that even such impellers are sensitive and easily wear out. This limits their service life and regular replacement of the impeller is required. These also cannot pump dry as both shaft and impeller can melt. This means that you cannot completely empty a tank with such a pump.

There are also other pumps, so-called bellows pumps for a mixed fraction liquid. These have high noise levels, are large and costly and create powerful pulsations in pipelines, and require extra pressure tanks to even out pulsating pressure. This technology does not work for the waste-sorting toilets for indoor use.

Diaphragm pumps can pump at high pressure into narrow tubes, but may not be used for liquids with particles and dirt. The have "check valves/membranes" which dirt and particles would prevent them from closing tightly, whereby pressure difference occurs and pumping is not possible.

Peristaltic pumps have tubing that are create pressure that are both complicated and expensive to produce, and have a high degree of wear, thus requiring regular service and have a high noise level. The cost, high maintenance and reduced flexibility rules it out for the purpose of the present invention.

A commonly used pump in drain wells is centrifugal pumps. These are robust and can pump particles and dirt. These are available with cutting impellers, but since they cannot create a negative pressure via air, they are placed standing so that the pump chamber is below the liquid level. These cannot then completely empty a tank when the impeller ends up above the liquid level and so-called airlocks "air pockets" arise that prevent liquid from being compressed. This also reduces its capacity to totally remove urine and its odor.

Other examples of centrifugal pumps are cutting centrifugal pumps, which are placed horizontally under the water lock of for example boat toilets. However, these do not separate the waste and are large, expensive, use a lot of energy and require about 2-3 liters of flushing water per use. The cutting pump also mixes the fraction further so that filtering of ex faeces and water is significantly complicated. One of the main objects of the present invention is to control the urine odor. One measure is to avoid urine odor, is to keep the urine content in the toilet as low as possible. An impeller pump or centrifugal pump, particularly a brushless DC pump, and more particularly one with a rigid or nonflexible impeller, has been found to work and be the best choice if constructional adaptations are made as according to the present invention. In the present invention, said pump types can pump without liquid and thus keep the urine content and thereby urine odor at a minimum. Moreover, the pump can also handle corrosive or demanding fluids.

If a urine pumping system does not work, for example, in the event of a power failure, you must be able to use the toilet anyway. A buffer tank that can receive urine when the pump is not pumping has therefore been placed between the urine separating bowl and the pump. The larger the buffer tank, the more urine it can contain if something goes wrong with the pump. In one embodiment of the toilet device, the buffer tank size is maximized in vertical direction by integrating the pump chamber into the bottom of said tank. The integration of buffer tank and pump makes it possible to avoid long power lines between these. This saves height, materials, components and manufacturing costs.

Moreover, in the case a centrifugal pump is used according to the present invention, it is placed in such a way that the entire pump chamber is filled by free-falling urine. This is to avoid occurrence of an air pocket around the impeller, as centrifugal pumps cannot compress air, these cannot "prime" themselves, i.e., first they suck gas and then liquid. The pump chamber should therefore be located at the bottom of the tank and the shaft vertically against the opening of the pump chamber in such a way that the pump chamber is the lowest point of the tank and thus filled with urine, enabling the impeller to always rotate in a liquid.

In another of the embodiments of the present invention, a pump motor of the type brushless DC motor is used. If the stator of said motor is being digitally controlled, there is provided a pump that has a very low height, (when the rotor shaft is vertical). This increases the possible height of the urine tank. This is a greatly increases the buffer/urine tank capacity. The digital drive further provides contactless transmission of the varying electromagnetic field that drives the rotor, which makes such a pump very robust with a low level of service. Another great advantage of brushless DC pumps in the connection of the present invention, is that the rotor and stator are separated from each other by a material that allows an electromagnetic field to pass. This means that the pump does not need special gaskets that seal against the rotor shaft. If liquid reaches the rotor, it does not affect electronics or the stator. The pump will thus not melt if it pumps dry. Another advantage of dry pumping is that you can see, from reading the pump's electricity consumption over time, whether the pump pumps liquid or not, and at what pressure.

The rotation of the impeller in the pump chamber helps to increase the mixing of urine and added stabilizing/hygiene substances. The rotation of the impeller, the design of the impeller and pump provide a higher and better mixing of urine-stabilizing substance and urine. This rotation creates turbulence in the liquid that also propagates outside the pump chamber, out to the buffer tank and tubing, thus further increasing the mixing.

This provides a significant improvement in the reduction of problems in slang, killing of organisms and the ability to recover nutrition from urine. Especially, if using substances with low solubility, of different density, or in gaseous form such as calcium hydroxide, powder or ozone. This also means that the urine stabilizing substance is also given the opportunity to more effectively purify the urine from medical residues or trace elements such as hormones or substances containing sensitive and personal information about health, etc.

The urine-stabilizing substance may be actively or passively delivered to the urine. In one embodiment, the urine-stabilizing substance is put in contact with the urine in a passive fashion. The device 1 may then comprise a passive dosing unit (not shown in the drawings) comprising a liquid, gel, powder, a dissolvable stone, et c, which releases the urine-stabilizing substance when the urine is allowed to come in contact with the material in said container, as it heads its way down the device. The container may for example be located in the container 2 or at the entrance/passage to the buffer tank 3. In another embodiment, the urine-stabilizing substance is added actively to the urine, for example in the buffer tank 3 or in the chamber of the pump 4. The manual addition of urinestabilizing substance by the user may be prompted by a signal (light or sound) from the device, when a urine measuring unit has detected at least a predetermined maximum amount of urine in the buffer tank. "Level" and "amount" may be used synonymously in the present disclosure. Normally, detection would be based on reaching a certain level (in height) in the buffer tank. However, the amount of urine may also be based on weight. In one embodiment, this signal may be an indication to the user to change the dosing unit. In another embodiment, said addition is done automatically, and the device 1 comprises a delivery device 5 for delivering the urine-stabilizing substance to the urine in the buffer tank or pump chamber. The delivery device comprises a container 5.1 for storage and delivery of the urine-stabilizing substance and a central control unit 5.2, which is in electronic communication with the container 5.1, which in turn is connected to the buffer tank 3 or the pump chamber 4 by a tubing. A measuring sensor 5.3, electronically connected to the central control unit 5.2, is arranged for detection of at least one predetermined maximum level of urine in the buffer tank 3. When the urine reaches the maximum level, the measuring sensor signals to the central control unit, which in turn signals to the container 5.1 to release the urine-stabilizing substance into the buffer tank 3 or to the pump chamber 4. In a device intended for manual addition of urinestabilizing substance, it may still comprise a urine measuring sensor and a central control unit. Once a predetermined maximum urine level has been reached, said sensor signals to the central unit, which then prompts the user by light or sound to add the urine stabilizing substance. A signal device 5.2.1 may for example be a LED light.

The central control unit is also electronically connected to the pump. In order to provide the correct dosage, at least one maximum level needs to be measured in the buffer tank, and that the pump can empty the tank between dosages. Preferably, two levels or more are measure using a float sensor or other sensor device. If the measurement provides information that maximum level 2 or 3 has been reached, a quantity of substance can be dosed accordingly, manually or mechanically. In this way, the correct amount of substance is dosed. The sensor thus also works to prevent overflow. Furthermore, after the substance has been dosed, the pump can start, mix the substance and urine, and emptying the tank. The sensor thus provides information that the tank is empty and the pump should stop pumping. If the sensor still signals that level 2 or 3 has been reached even after the pump should have emptied the tank, it is signaled to the user that the emptying is not working and that service is required.

In one embodiment, the delivery device is also connected electronically to the pump. When the measuring sensor has detected a predetermined maximum level of urine in the buffer tank, the measuring organ starts the pump, which mixes the urine and urine-stabilizing substance in the pump chamber and buffer tank by the turbulence is creates. The pump may stop after a predetermined time. In a further embodiment, the measuring sensor 5.2.1 also detects a predetermined minimum level of urine in the buffer tank or the pump chamber and signals to the pump to stop pumping when said minimum level has been reached. The pump used is also capable of pumping without liquid without getting destroyed. This makes it possible to avoid storing urine in the toilet and the odor that may entail. In alternate embodiments, the measuring sensor may detect multiple urine levels. The destination of the pumped urine is described below.

The device 1 the is thus devised such that a predetermined amount of urine is detected, and the required amount of urine-stabilizing substance is added to it. The turbulence of the pump creates a quick stabilization of the urine, preventing odor and preserving the nutrient value of the urine. The device may also be equipped with one or more electric check valves 6, preventing urine to flow back to the buffer tank if it is placed at a lower point then the storing tank. Control of the urine level and pump can be used to control the electric check valves, or to pump out the urine buffer tank if the check valves malfunction and urine refills the tank.

In a further embodiment, the pump is integrated into the bottom of the buffer tank to maximize the buffer tank size. In another embodiment, the pump is separated from and at a distance from the buffer tank by a tubing. In these cases, the pump is preferably integrated in the bottom of the tank or below the tank, and with the impeller in horizontal position, such that the pump is always primed with urine and can operate without air problems. This also makes it possible to fully empty the urine buffer tank, thus minimizing any bad smell and the risk of precipitation of salts or biofilm formation. Complete emptying of the buffer tank also provides for a more accurate addition of urine stabilizing substance. In that case of the pump being at a distance from buffer tank, the length and size of the tubing are adapted such that the turbulence is still created in the pump chamber and buffer tank. Typical dimensions of such a tubing are 3-10 cm in length and 1-2 cm in diameter. In both such cases, the pump is preferably essentially flat (i.e., have a low vertical height) to be able to maximize the buffer tank size while keeping the height of the toilet sufficiently low. In all embodiments, the pump is preferably a pump that can generate turbulence in the buffer tank, and selected from the pumps mentioned above.

Integration of the pump in the bottom of the buffer tank means that the pump is located at a lower plane than the majority of said bottom. In one embodiment, the buffer tank and housing of the pump are fully integrated into each other, i.e., they are produced as one piece, and the pump motor is fastened to the pump housing area if the tank bottom. In another embodiment, the pump is integrated into the bottom but located directly under the tank, and the housing is fastened to said tank, for example by glue. The motor of the pump is preferably screwed onto the pump housing to facilitate maintenance.

In one embodiment, the pump is located below the corner of the tank. This makes it possible to have an outlet tubing leaving the pump housing vertically alongside the buffer tank and avoiding a bend in the tubing to provide for better flow, less precipitation, the possibility to remove the tank in case if a power failure, et c). This facilitates production and makes the construction more compact. The tubing may be fitted with a check valve for prevention of urine flowing back into the buffer tank 3. In another embodiment, the tubing continues into an exterior opening part of the tank (not shown in the drawings) that acts as an outlet to the storage tank 7 and which is fitted in a check valve. While mounted, said exterior part pushes into the opening of the check valve, keeping an open connection between the tank 3 and tank 7. At the removal of the tank 3, the exterior opening part of the tank leaves the check valve opening and closes the check valve, thus preventing urine leakage when removing the tank 3.

The urine and fecal containers, and urine buffer tank are easily removable modules to facilitate cleaning, maintenance, or replacement.

In one embodiment, the container 2 for receiving urine and buffer tank 3 are one and the same. The pump is then located at the same location as described above. In another embodiment, the device may comprise several urine containers 2 leading urine to one buffer tank 3. These embodiments represent a construction of the device that may be used in for example public urinal facility for one user or several simultaneous users.

The selection and construction of the pump, enables easy service and replacement, easier manufacturing, and fewer components.

The delivery device 5 is adapted to receive urine-stabilizing substances selected from acids, bases, oxidizing substances, liquid, gas, and other suitable solids or liquid substances with the ability to stabilize urine. In one embodiment, said delivery device is arranged to generate the urine-stabilizing substance electrochemically, for example in the container 5.1. In one embodiment, the generated substance is ozone.

Should substances such as ozone, highly oxidizing acids or bases be used, the ability to dose the right amount of substance to the tank at the right time is critical. It is especially important when gases such as ozone are used, as ozone, if not mixed in liquid or added in excessive quantities, can leak into the surrounding rooms and be harmful to user health.

If ozone is used as a urine stabilizing substance, it can also be used to reduce odor and growth in the ventilation system for urine and faeces often found in dry toilets. This will especially be an advantage if the correct amount can be dosed into the urine buffer tank. Furthermore, if the correct substance is added, the freezing point of the liquid can be lowered, which is an advantage if used in for example cottages in cold countries. Positive pressing pumps and controlled addition of substance according to the present invention, enables urine to be flexibly processed further. After stabilization, there is provided a urine fraction where most of the nitrogen is retained in its odorless and beneficial form urea, with a higher fertilizer value than if the nitrogen departs as ammonia to the air ex via ventilation.

If urine is to be recycled for use as plants fertilizers, one must also be able to handle that a certain amount of faeces may end up in the urine fraction. Faeces contains pathogens and organisms that make the faeces-contaminated urine harmful to health and also contributes to the formation of biofilm in the throughout the sanitation device, in particular in the tubing. This may also create blockage. As mentioned above, a sanitizing substance may be added to prevent biofilm formation. Underdosing of said substance, will allow biofilm to form, overdosing may on the other hand increase the risk of mineral precipitates, generating a similar blockage problem. In addition, the addition of a sanitizing substance may reduce the nutrient value of the urine (destabilizing instead of stabilizing) and its potential as a fertilizer component, i.e., to retain the nitrogen in the form of urea.

If the urine is to be processed further, chemistry adapted to the process such as acids is required as in the space station to retain the nitrogen in the form of urea. However, acids often lead to problems because many urea metabolizing organisms, such as yeast, mold, lactobacteria, acetobactes and others are acid resistant, which is problematic for the ISS. To avoid this, strong and complex chemicals that are difficult and toxic to handle for lay people are required. But even though these are used on the ISS, there are problems with biofilm.

The present inventors have discovered that if you are going to use strong acids, bases or highly oxidizing substances such as ozone or hydrogen peroxide, or other substances, it is important to know what amount of urine the chemistry is added to. Overdosing or underdosing has negative consequences on stabilization and control of biofilm and mineral precipitate formation. Control of the amount of urine is critical. The present invention exerts this control using the urine level measuring sensors.

The literature also describes how magnesium hydroxide or calcium hydroxide can be used for stabilization. However, the present inventors have found that these and other substances may be more or less insoluble if mixed with substances with a density other than that of urine, such as gases, ozone, or pellets/ powders, but that the stirring of the urine and urine-stabilizing substance provided by the pump of the present invention is still able to provide good with the urine. All embodiments of the device 1 described above and below, may also comprise a container 8 for receiving faeces.

One problem of waste-sorting toilets is the handling of large volumes of urine. One way to reduce the volume would be to reduce its water content. If urine processes are to contain evaporation of the water in urine to obtain a concentrate of nutrients for easier handling and cheaper transport, and today the urine is allowed to fall naturally to tanks outdoors. To be energy-efficient, the water may be reduced by evaporation by the sun. The problem is that the tanks must then be placed under the urine-receiving container and will thus have a small surface exposed to the sun, unless you can increase the bottom area of the tank. However, this requires large land areas, something that is rarely available in cities or slums. One solution to this is to place the toilet higher up with stairs to increase the height of the tank, thus enabling the toilet tank to be more exposed to the sun while minimizing its footprint. However, this reduces the availability of the toilet and makes the system more expensive. Vacuum tanks cannot be used to ventilate the water vapor as these must be airtight for negative pressure/vacuum to occur, which makes the construction complicated and expensive.

According to the present invention, the pump can move urine via the pressurized tubing system to storage. The device 1, may in a further embodiment comprise a storage tank 7 for receiving and storing urine. Said storage tank may be placed indoors or outdoors. In one embodiment, the urine can be moved towards gravity to said storage tank. This tank can be high with minimal bottom area. Thus, it takes up less space, which is good if the tank is for example placed indoors. The positional energy in the urine can then be used to move the urine to e.g., irrigation in the vicinity, precipitation, nitrification/denitrification or other desired processes, or further transportation. Used flexible garden hoses, which are inexpensive, the toilet can be easily plugged into standard fluid handling systems in cultivation. This makes recycling easier and more accessible. A system placed above ground reduces the risk of flooding and leakage of waste into the surrounding area.

If the urine is led to an external storage tank with pressure (as produced with a pump) enters near its bottom, the smell is reduced. Any insoluble substances that have settled on the bottom ex CaOH will also distribute better throughout the urine via turbulence in the fluid and layering and uneven mixing of substances and urine is avoided.

If placed outdoors, the storage tank may in one embodiment be dark or black (with or without transparent peak that leads down the light to the urine) for the best absorption of sunlight to heat the urine to evaporate water and reduce the urine volume. It is especially important to move the urine in height if you want to use solar heat. Then this is most easily placed outdoors in as shade-free a place as possible. For example, a roof or an open surface and exposes the urine tank to sunlight and heat. Water may also be vented off/evaporated using a fan 7.1, which may be driven by a solar panel 7.2 or other power source. The water may also be evaporated by an electrically powered heating element 7.3. The water vapor leaves the storage tank via a vent 7.4 One or more of these evaporation means may be used.

In the tank, the sun transfers energy in such a way that the mixture of urine and stabilizing substance is heated and the water turns to water vapor. This is vented out by the fan via a vent 7.4 in the tank. An electronic control in the toilet can also be connected, directly or wirelessly, to sensors in the storage tank or evaporative tank in such a way that status, e.g., temperature, fill rate, etc. can be measured and conveyed to users or monitoring systems. If the sun is not shining or it is too cold, extra heat can be supplied and controlled by, for example, an electric heater or a heat pump 7.3.

With the help of the pump, the tank can be placed higher up and be exposed to more sunlight than if the pump is not included and the tank is filled only by free-fall.

If the tubing leading from the toilet to the storage tank are also dark or black, and located so they are exposed to sunlight, this extra solar heat can be used to then evaporate the liquid and recycle the nutrients of the urine.

In another embodiment, the urine is pumped to a storage tank located on ground level containing a mixture of sawdust and lime in different layers, to be mixed with the gray water, and is purified through biofilm on the wood shavings and precipitate in the lime to so-called high-level protection N<70%, P<50%, BOD< 90%, before the purified mixture of urine and gray water is released. In another embodiment, the urine is pumped into a ventilated container containing a mix of sawdust and soil to be co-composted with the sawdust while venting leftover liquid. In such a system, it is an advantage if the amount of urine pumped from the toilet is checked by a sensor in the container that communicates with the control electronics in the toilet.

The units or parts of units described above are, if not indicated explicitly, connected by tubing. Said tubing may be in some cases rigid, but are in general flexible for the purpose of construction freeness. The tubing may be made by various materials such as metals, plastics, rubber, etc. If not specified otherwise in the present disclosure, the tubing preferably has a diameter of 5-32 mm. In one embodiment, the diameter is 12-19 mm. In the case of electronic communication between units or parts of units described above, said communication may be through electric wiring or wireless connection. There are control units including microprocessors and software regulating the communication and control of for example the measuring of urine, signal prompting manual addition of urine stabilization substance and automatic release of said substance, operation of the pump, etc.

In a second aspect of the invention, there is provided a method of treating human waste that comprises to provide a device 1 for treating human waste that comprises a container 2 for receiving urine, a buffer tank 3 for receiving and intermediately storing urine, and a pump 4 whose pump chamber is in open connection with the buffer tank, as well as a urine-stabilizing substance, wherein the method comprises the steps of to receiving urine in the container 2, when a user uses the device 1, and leading it, preferably by free fall, to the buffer tank 3 and further down into the chamber of the pump 4, while putting the urine-stabilizing substance into contact with the urine, and mixing the urine and the urine-stabilizing substance, by operating the pump, in the buffer tank and the pump chamber using the turbulence that the pump creates in these.

In an embodiment, the method further comprises providing a delivery device 5 for delivery of a urine-stabilizing substance, and a step of actively delivering it to the urine to the buffer tank 3 or the pump chamber 4. In another embodiment, the method further comprises providing a delivery device 5 comprising a container 5.1 for receiving and storing the urine-stabilizing substance, and which is connected to the buffer tank or pump chamber by tubing, a measuring sensor 5.2 arranged to detect at least a maximum level of urine in the buffer tank, and which is electronically connected to and controlling the container 5.1 and the pump 4, and where the method further comprises a step where the measuring sensor 5.2 measures a maximum level of urine in the buffer tank and electronically signals to the

Device specifications

The tubing preferably has, if not specified otherwise in the present disclosure, a diameter of 5-32 mm. In one embodiment, the diameter is 12-19 mm.

The pump pressure may be 1 to 10 bar, but may be various embodiments be 2-8 bar, 3-7 bar, and 4-6 bar. The buffer tank size may be 3-10 liters, and may in one embodiment be 4-5 liters. The buffer tank may for example have straight top, at bottom surface inclined against the pump house entrance, and with a curved front and back. The buffer tank may for example have straight top, at bottom surface inclined against the pump house entrance.

If the urine-stabilizing substance is an acid (e.g., citric acid, oxalic acid, benzoic acid) may have a pH less than 4, for example pH 2.5-3.5. If being a base, the pH may be above 10, for example 10.5-11.5.

It may be supplied as ozone at e.g., 1-350 mg/h. Other examples are hydrogen peroxide, enzymes, NBPT, and potassium sorbate, which may typically be used at 0.1-5% in relation to the urine content/volume. All substances are added at an amount that achieves the desired sanitation effect.

The urine storage tank may be 50-4000 litres, for example 100-1000 litres. Drying of the urine may suitably be performed at 25-55°C. Venting may be performed at 25-500 m ³ /h, e.g., at 50-250 m ³ /h. Drying may be suitably performed to 5%-50%, preferably 10-25%, of the original weight.