WO2019145608A1

WO2019145608A1 - Closed dry toilet system, and method for processing toilet waste

Info

Publication number: WO2019145608A1
Application number: PCT/FI2019/050055
Authority: WO
Inventors: Raini KIUKAS; Pirjo NIEMELÄ; Jorma KUOSA
Original assignee: Digi Toilet Systems Oy
Priority date: 2018-01-24
Filing date: 2019-01-24
Publication date: 2019-08-01
Also published as: FI20185068A1; EP3742949A4; EP3742949A1; FI128612B

Abstract

A closed dry toilet system is presented, which comprises at least one dry toilet unit (10), at least one encapsulated conveyor (14a, 14b) for toilet waste, sealed to at least one dry toilet unit (10); a composter (20) having an inlet and an outlet, the inlet being sealed to said conveyor (14a, 14b, 15, 16, 17) for toilet waste and being configured to receive the dry-toilet waste from said at least one conveyor. A method for processing toilet waste is also presented, the method comprising providing said closed dry toilet system or a movable transport container; composting toilet waste collected in the composter, for a sufficient time for hygienizing the toilet waste, to obtain processed toilet waste.

Description

Closed dry toilet system, and method for processing toilet waste

Field of the application

The present application relates to a closed dry toilet system comprising a corn- poster. Furthermore, the application relates to a method for processing toilet waste in said dry toilet system.

Background

A dry toilet is a toilet in which waste, i.e. toilet waste, is not flushed with water but collected in a tank, a container, a heap, a pit, or the like. The toilet waste can be subjected to various further treatments: it can be moved away for composting, or dried. The dry toilet may be placed indoors or outdoors.

There are often odour problems caused by toilet waste in dry toilets. In flush toilets, the toilet waste is flushed with water away from the toilet unit, such as a toilet bowl, or a urinal, and the toilet unit is cleaned at the same time. Furthermore, the water in the piping prevents odours from spreading out in the toilet facilities. The odour problem is thus one factor limiting the large-scale adoption of dry toilets.

Normally, dry toilets are implemented as facilities of a single toilet unit, particularly a toilet bowl, and such toilet units are difficult to combine. The maintenance of facilities comprising several toilet units is problematic, particularly in public areas, and the toilet waste has to be separately collected and removed from the toilet facilities. Commonly used dry toilet units provided with seats are relatively large, which further complicates the building up and management of larger facilities.

Brief summary

The present application describes a closed toilet system which makes it possible to build up facilities with several toilet units and to manage and process the waste produced in the toilet in an efficient way.

The application relates to a closed dry toilet system comprising

- at least one dry toilet unit,

- at least one encapsulated conveyor for toilet waste, sealed to at least one dry toilet unit, - a composter having an inlet and an outlet, the inlet being sealed to said conveyor for toilet waste, and the composter being configured to receive the dry-toilet waste from said at least one conveyor, and

- optionally a tank for the end product, which may be sealed to the outlet of the composter.

The application also relates to a movable container, such as a transport container, which comprises said closed dry toilet system.

The invention also relates to a method for processing toilet waste, the method corn- prising

- providing said closed dry toilet system or transport container,

- composting toilet waste collected in a composter for a time sufficient for hygieniz- ing the toilet waste, and

- optionally transporting the hygienized toilet waste to a tank for the end product.

The main embodiments are presented in the independent claims. Other embodi- ments are presented in the dependent claims. The embodiments presented in the claims and the description may be freely combined, unless otherwise specified.

Because the dry toilet system is closed, it enables careful management of odour problems as well as the toilet waste treatment process. The whole process takes place in the closed system, whereby unprocessed waste cannot come out of the system; furthermore, no material that might affect the quality of the end product can enter the process from the outside. The output from the system is composted toilet waste which has been processed in a controlled way to achieve a desired level of treatment. In practice, the end product obtained is hygienized material which does not contain, for example, living pathogens. Consequently, its handling is safe and does not cause odour problems.

When a negative pressure is applied to the toilet system, odours cannot spread via the toilet units but can be discharged from the system via other channels.

The system of several toilet units can be implemented in a space-saving way and particularly in a single level. In the toilet units, there is no need for separate tanks taking space and having to be emptied. When a suitable conveyor for toilet waste is used, for example a screw conveyor, a vibrating conveyor or a scraper conveyor, the toilet waste can be conveyed from the toilet units in a substantially horizontal plane. Thus, the system does not require extra space in the vertical direction, such as the construction of pipes between floors. Such a system can be built up in e.g. a movable container, such as a transport container, or other existing premises, such as a building or the like. This makes it possible to provide toilet systems for such events or areas where they are needed. Examples of events include e.g. public events, such as festivals or other outdoor events. A required number of movable dry toilet systems, implemented for example in containers, may be provided for such events. Another example of the need of toilet systems is, for example, regions struck by disasters, where large numbers of people have to be sheltered in, for example, camps or other temporary lodgings. Such areas may be provided with either ready- to-use movable dry toilet systems, or systems may be built up rapidly in, for exam- pie, an existing building which was not initially designed for use as toilet facilities. Since there is no need to install separate pipes in the buildings, the implementation of the toilet system only requires, in practice, an underlying base, such as a floor or even a relatively even ground surface.

The toilet system may be implemented to recover anything useful from the toilet waste, whereby, in practice, only water is left, which can be further recycled or even drained to the ground or to a sewer. It is possible to recover, for example, composted material; nutrients, such as nitrogen, potassium and/or phosphorus; carbon dioxide; water; and/or heat. The heat produced in the composter can be utilized in other parts of the system, for example, for sterilizing or evaporating a liquid, for heating the toilet facilities, or for energy production. An efficiently working toilet system makes effi- cient waste processing and a high standard of hygiene possible without added chemicals, such as chemicals used for sterilization or cleaning. The system may run in continuous operation.

The operation of the toilet system may be controlled on the basis of data collected by sensors in the system, whereby in response to the collected data, control measures may be taken, manual or automated, which enable the desired operation of the system and the desired processing of toilet waste. In this way, an end product of desired quality can be obtained, irrespective of the starting material. As the corn- position of the accumulating toilet waste can vary to a great extent, for example with respect to the contents of urine and feces, and other material included in the toilet waste, the operation of the system is preferably controllable in such a way that the process is not disturbed and that desired end products are obtained. For example, relatively much more urine than feces will be collected in toilet systems supplied for beer festivals compared with systems supplied for a different type of public event. Moreover, significant quantities of material other than urine or feces may enter the toilet waste, for example toilet paper, other paper, tampons, sanitary towels, vomit, water, drinks, trash, or the like, which may be thrown in toilet units by toilet users. Therefore, it may be necessary to remove or decrease one or more of these mate- rials, to obtain the desired composition of the end product.

Description of the drawings

Figure 1 exemplifies a dry toilet system built up in a movable container; Fig. 1 a shows a top view of the dry toilet system, and Fig. 1 b shows it in a side view.

Figure 2 shows examples of toilet bowls, Figs. 2a and 2c in side views, and Fig. 2b in a top view.

Fig. 3 shows a processing compartment of a dry toilet system built up in a container, wherein a pipe containing a screw conveyor and coming from a toilet compartment is connected to an automated composter.

Fig. 4 shows a dry toilet bowl, built up in a container and installed on an encapsulated screw conveyor.

Fig. 5 shows a dry toilet built up in a container, in which the toilet bowls are connected to the same encapsulated screw conveyor.

Fig. 6 shows a dry toilet bowl for the disabled, built up in a container and installed on an encapsulated screw conveyor equipped with an actuator for applying it. Ven- tilation pipes for providing the system with a vacuum and ventilation are also con- nected to the encapsulation of the screw conveyor.

Detailed description

The application describes a closed dry toilet system which, according to an example, may be functionally divided into a toilet compartment and a toilet waste processing compartment. These may be physically separate spaces, for example in different rooms, in different movable containers, or separated from each other by a wall, or they may also be arranged in the same space. In an example, the toilet compartment is in one movable container, such as a transport container, and the processing com- partment is in another movable container, such as a transport container. In another example, both the toilet compartment and the processing compartment are in the same movable container, such as a transport container. The dry toilet system may be run in batch operation or continuous operation.

The dry toilet system comprises at least one dry toilet unit. The toilet system may comprise several dry toilet units, preferably two or more. The dry toilet unit may refer to any toilet unit suitable for the dry toilet, such as a toilet bowl, a squat pan, a urinal, a drop hole in a plane surface, or the like. Such a toilet unit is configured to be used without flushing, or with little water. In the toilet system, one or more toilet bowls, as well as one or more urinals, may be arranged in the same space, such as a toilet compartment. For example, each toilet unit, such as a toilet bowl, may be placed in a separate cubicle which may have a door, or in a space separated by a wall. The cubicles or other corresponding spaces may be relatively closed, such as bounded by walls and/or doors on all sides, and preferably without gaps at the top or down below. This is to secure an air flow from an air inlet at the top of the cubicle, such as in the ceiling, via the toilet bowl into the system. Two or more toilet units may be coupled together via their discharge openings. Preferably, the toilet units do not comprise tanks for toilet waste. The dry toilet units, such as waterless toilet bowls, squat pans, or urinals, may comprise a water and/or soil repellent coating, for example on surfaces exposed to feces or urine.

Figures 2a and 2b show an example of a toilet bowl. The toilet bowl10 comprises a seat for receiving the user, a bowl 44 which is open at the top for receiving toilet waste, and a discharge opening 46 in the bowl, through which the toilet waste exits or is discharged from the toilet bowl and is preferably removed. The discharge open- ing 46 may be covered with a baffle which can be opened and closed, for example manually or automatically. The discharge opening may be connected to a pipe, a duct, a conveyor, or the like, for removing the toilet waste. The toilet bowl may be equipped with a sensor, such as a pressure sensor, an optical sensor, or a switch detecting the presence of a user and/or toilet waste; on the basis of the state of the sensor, the system may, for example, turn on a conveyor for toilet waste.

A pissoir or urinal, which may refer to the same thing, comprises a trough open at the top, a bowl, or a receiver for receiving urine. This opens further to a discharge opening, through which the urine exits or is discharged and preferably removed. The discharge opening may be connected to a pipe, a duct or the like, for removing the urine. The urinal may be equipped with a sensor, for example an optical sensor, such as an infrared sensor, which reacts to the vicinity of a user and is connected to one or more control units which, in turn, may be configured, on the basis of this information, to open or close the discharge opening of the urinal, and/or to control the flow of urine in the system. For example, when the user stands in the vicinity of the urinal, the valve of the discharge opening is opened, and correspondingly, after the user has left, the valve is closed, to reduce or prevent the spreading of unwanted odours in the toilet facilities. The urinal may also comprise a membrane closing the discharge opening and configured to open when subjected to pressure from the urine. The membrane closes when the flow of urine ceases. The membrane is sim- ple and may act independently and thereby does not require e.g. further mecha- nisms or control.

A toilet bowlmay also comprise means for separating urine and feces, for example in the structure of the toilet bowl, or an inner part of the same, whereby it is called a urine-diverting dry toilet. This kind of a solution is shown in Fig. 2b. In this way, urine and feces can be conveyed to different places and/or processed separately, prefer- ably in different ways. The diverting toilet bowl may comprise, for example, a first opening, recess or compartment 48 for receiving urine in the front part of the bowl 10, and a second opening, recess or compartment 46 for receiving feces in the rear part of the bowl, in relation to a person sitting on the seat. Each compartment or recess has a separate discharge opening, via which the separated urine or feces exits or is discharged and can be conveyed further or removed, and preferably sub- jected to further processing, for example the isolation one or more substances. Said first and second openings, recesses or compartments may be implemented as a separate detachable diverting trough which contains both and is attachable to and detachable from a toilet bowl, for example as a diverting trough made of plastic. The toilet bowl may comprise a sensor and/or a valve, or a membrane for closing the discharge opening, whose structure and/or function corresponds to that described above in connection with the urinal, and the toilet bowl may be configured to operate in a similar way with respect to urine.

In one embodiment, the dry toilet system comprises means for separating urine from feces, for example in the dry toilet unit or in the conveyor for toilet waste, and pipes for diverting urine. Urine is diverted from solids, such as feces and/or other solids, and/or it can be diverted from a processing tank and/or a composter. Preferably, the urine is separated already in the urinal or toilet bowl, so that it cannot be mixed with feces and turn into contaminated infiltrated fluid. The urine, either separated at some stage or collected from urinals, can be conveyed to a tank, for example a urine stor- age tank, processing tank, and/or to further processing. The urine may be subjected to further processing, for example recovery of substances, such as phosphorus, potassium and/or nitrogen, and/or precipitation of the above-mentioned and/or other substances, filtering of insoluble substances, and/or further purification steps, to obtain purified urine, at best usable water. Water or aqueous fluid may be used, for example, for flushing or washing the system in a maintenance step. Although the toilet system is waterless, it may be sometimes necessary to run water or the like in the system for cleaning it, for example via the toilet units. Such a flushing or mainte- nance step may be automated to be taken at certain intervals or when necessary, preferably when the system is otherwise not in use. The flush water may finally end up in the processing tank or composter, where it wets the material to be composted.

The toilet system comprises at least one conveyor 14, 14a, 14b for toilet waste, sealed to at least one dry toilet unit in a sealed way. The conveyor is encapsulated, and preferably the encapsulation 42 is sealed to at least one dry toilet unit 10 and, for example, the encapsulation of another conveyor, whereby the system can be implemented as a closed system. The encapsulation refers to any suitable structural solution which delimits or separates the conveyor in a space of its own which can be isolated from the space outside it. The encapsulation may comprise walls around the conveyor, forming a tubular structure whose one end or both ends, or parts of the walls of the encapsulation, may be open and connectible to toilet units, other encapsulated conveyors, tanks, or compostors. An end of the encapsulation which is not connected to anything, may be closed by e.g. a wall, to secure that the encapsulation is impervious. The conveyor for toilet waste is configured to receive toilet waste from at least one dry toilet unit.

In this context, "closed" system means that the joints between at least the toilet unit(s) and the composter in the toilet system are sealed, particularly when in use. Consequently, the parts of the system are "sealed" to each other, for example at least the toilet unit(s), conveyor(s) or the respective encapsulation(s), and the corn- posters), but also possible other parts of the system, such as processing tank(s), tank(s) for end product, pipeline(s), encapsulations, inlets and outlets included in the system, such as means for adding or discharging one or more substances, con- nections for one or more sensors, and/or other connections. Sealed may refer to air- tight or water-tight, or substantially air-tight or water-tight, but complete air or water- tightness is not always necessary, because the vacuum in the system reduces the release of odours from, for example, the joints. However, the system is open via the toilet units at least from time to time, which is necessary for the operation of the system and, for example, for providing a negative pressure in the system. The tank(s) for the end product, such as the tank(s) for composted product and/or urine, are preferably closed, at least partly and/or at times, for example during use. In general, the outlet or outlets through which the processed toilet waste and/or col- lected and/or processed urine can be discharged, or the tanks connected to them, can be opened and/or emptied.

In an embodiment, several toilet units, particularly toilet bowls, are connected to the same conveyor. One or more toilet units, preferably toilet bowls, may be connected to the same conveyor so that the transferring part of the conveyor, such as a screw, a spiral, a trough, a chute, a pan, a plane surface, or pushers, extends or extend via the outlet of the discharge openings of the toilet units, for example below them, whereby toilet waste exiting via the discharge opening will end up on the conveyor and be removed from the toilet unit. The transferring part of the conveyor may be coated with a soil-repellent coating, or at least part of it may be made of a soil- repellent material, such as Teflon coating (polytetrafluoroethylene) or its derivative, abs plastic, or the like. The toilet bowl may be modified for fitting the conveyor to it. For example, the lower part of the toilet bowl may be provided with an opening 41 for a conveyor 14, as shown in Fig. 2a. The conveyor 14 is encapsulated in an encapsulation 42 which is sealed to the toilet bowl 10, more precisely its discharge opening 46. In the example, the conveyor 14 comprises a trough 40, for example a band conveyor whose lateral edges are configured to be elevated. In Fig. 2b, broken lines illustrate the location of the conveyor in relation to the toilet bowl; in other words, the conveyor runs through the toilet bowl, and by this principle, more than one toilet bowl may be connected to it. The conveyor for toilet waste may be any suitable conveyor configured to carry the toilet waste, particularly feces, to a desired place. The conveyor may be a mechanical conveyor which is connected to an actu- ator and configured to be driven, for example moved, by the actuator. The conveyor is preferably a conveyor running in the horizontal plane or substantially in the hori- zontal plane. The conveyor, particularly a conveyor of the first stage, may be installed in the horizontal plane or at least partly in the horizontal plane, or substan- tially in the horizontal plane, for example under the toilet units, or at their bottom, such as in openings made at the bottom. "Partly in the horizontal plane" means that at least part of the conveyor is in the horizontal plane. "Substantially in the horizontal plane" may include a relatively small angle, such as an angle of 0 to 3°, 0 to 5°, or 0 to 10°, even 0 to 15°, to the horizontal plane. Flowever, a large angle will increase the need for space in the vertical direction. The system may comprise, for example, a flat and/or low encapsulation, having a height of e.g. 5 to 20 cm, extending under a row of toilet bowls and comprising an opening for each toilet bowl. The width of the encapsulation may be greater than its height. The conveyor may be selected from, for example, a screw conveyor, a vibrating conveyor, a belt conveyor, and a scraper conveyor.

A screw conveyor comprises a spiral screw which is arranged in a frame, an encap- sulation, a pipe, or a trough; is rotated by an actuator; may or may not have a shaft; and conveys material upon its rotation within the frame, encapsulation, pipe, or trough. The screw conveyor is particularly suitable for conveying solid material, and it can be implemented in an encapsulation or pipe which has a relatively small diameter but which may still, on the other hand, be very long. Stopping the screw conveyor prevents the toilet waste carried by it from being conveyed further or dis- charged. The encapsulation of the screw conveyor, the pipe, or the like may be provided with an opening for each toilet unit, for receiving toilet waste in the con- veyor. One form of a screw conveyor is a spiral conveyor. The spiral conveyor corn- prises a spiral in an (outer) pipe, whereby the actual screw conveyor is formed by a spiral spring, and the outer pipe may be, for example, a plastic pipe. The spiral con- veyor may also be installed to be at least partly curved, if necessary. Its spiral and/or pipe may be flexible. Spiral conveyors have a light construction and are also suitable for conveying distances as long as 13 meters. Figure 2c shows a spiral conveyor 14 installed in an encapsulation 42 which is arranged in an opening 41 below a toilet bowl 10, to receive toilet waste falling via a trough 40. The toilet bowl 10 comprises an outlet 43 for diverting urine separated in the bowl. The screw of the screw con- veyor, as well as the spiral of a screw conveyor, may be made of a metal, plastic, composite material, or another suitable material. Preferably, the material is of light weight, such as plastic, plastic composite, light metal, such as aluminium, or the like, whereby it is easier to move and the system is more reliable in operation. The material may also be elastic, whereby it may be packed against the inner wall of the conveying pipe, which reduces the accumulation of waste in the conveyor structure.

A vibrating conveyor is provided with conveying power from asymmetric vibration. By the vibration, pieces to be conveyed can also be arranged in a desired position and density. The vibrating conveyor may comprise a trough-like, chute-like, pan- like, or planar running section, on which toilet waste is passed from toilet units and conveyed further by vibration. The vibrating conveyor allows embodying a conveyor in a shallow space, for example in a space provided under the toilet units. This saves space and makes it possible to implement the toilet system in a plane and in a rela- tively shallow space. The moving part of the vibrating conveyor may be perforated, which makes it possible to screen the material or to separate liquid from solids. This may be useful, particularly if the toilet bowls are not of the diverting type, and urine or other liquid material entered in the toilet should be separated from the rest of the toilet waste. In this case, a trough, a pipe or the like may be arranged underneath the vibrating conveyor, for receiving the separated urine and/or for conveying it fur- ther, for example, to a collecting tank, a processing tank, and/or further treatment.

In a belt conveyor, a loop-shaped belt runs around at least two pulleys, at least one of them being a driving pulley. The actuator moving the belt, for example a traction motor, may be placed within the driving pulley. The top section of the belt slides along a smooth surface, or freely rotating supporting rolls are provided under it. The belt may be guided to have trough-like edges, to prevent leaking of toilet waste from the belt to the side. The belt conveyor may be vibrated to prevent adhesion of sticky material. In lifting conveyors, the conveyor belt may comprise ribs at regular inter- vals to prevent material from slipping backwards.

A scraper conveyor comprises a frame, an encapsulation, a trough, or a tube, in the same way as a screw conveyor, but the material is carried by blades, or scrapers, fastened to a running chain.

Said conveyors make it possible to convey toilet waste in the horizontal direction or in a substantially horizontal direction or plane, which makes it possible to implement the toilet system in a single level and saves space. "Substantially horizontal" may comprise an angle of 1 to 20, 1 to 10, or 1 to 5 degrees with respect to the horizontal plane. The actuator running the conveyor may be controlled so that the conveyor is only activated when needed, and only moves the length required. A signal for acti- vating the conveyor may be received from a sensor connected to the toilet bowl or another sensor in the toilet cubicle, for example an optical sensor, such as an infra- red sensor, or a switch on the door, such as a switch on the lock, or a sensor con- figured to detect the locking of the door. The passage of toilet waste in the system may also be controlled and adjusted for other reasons; for example, for processing a given quantity, toilet waste can be conveyed forward to a given stage at a given time. This can be implemented by one or more control units connected to the toilet system and configured to control the system, and by one or more sensors connected thereto for detecting the state of the system, and by one or more actuators con- nected thereto, for example an actuator for a conveyor, configured to be controlled by the control unit/units. Preferably, the actuator for the controller, for example an electric motor, is arranged outside the encapsulation of the conveyor, whereby it may be connected to the encapsulated conveyor by means of a shaft, a belt, a chain, or the like. This is to reduce the risk of soiling and/or corrosion of the actuator, and to facilitate its use and maintenance.

One or two or more conveyors for toilet waste may be provided. In the case of two or more conveyors connected to toilet units, the toilet waste conveyed by them can be combined, for example by means of a further conveyor which may be of a similar or different type than said conveyors collecting from the toilet units, which may be called conveyors of a first stage. The further conveyor, which may be called a con- veyor of a second stage, may be arranged, for example, perpendicular to the two or more conveyors, at their ends, whereby the conveyor of the second stage collects and combines the toilet waste conveyed by the conveyors of the first stage, and conveys it further to the next stage. The conveyor of the second stage may also run in the horizontal plane. The next stage may be a composter, or a possible pre-pro- cessing stage preceding it, and it may comprise a separate tank, such as a pro- cessing tank. At this stage, the system may further comprise a separate conveyor of a third stage, such as a horizontally running conveyor for conveying toilet waste from the conveyor of the second stage to the tank of the pre-processing stage or to the composter. The conveyor of the third stage may be needed, for example, if the system is implemented in a limited space, for example in a transport container, whereby the subsequent stages may be separated from the toilet facilities, behind a wall, in practice in a toilet waste processing compartment. The conveyor of the third stage may be similar to or different from the conveyors of the first and/or sec- ond stages. It may run horizontally, substantially horizontally, or even partly verti- cally, depending on the structure of the system and the needs. Furthermore, a con- veyor of a fourth stage may be needed, which may run at least partly in the vertical direction, for example an inclined conveyor. This may be needed in a limited space, e.g. in a transport container where one or more tanks or apparatuses of the subse- quent stage are installed on an upper tier, for example the tank of the pre-processing stage, or the composter. The conveyor of the fourth stage may be similar to or dif- ferent from a conveyor of a lower stage. It may raise the toilet waste to a height of, for example, 1 to 3 m, such as 1 .5 to 2.0 m, for example at an angle of about 45 degrees.

The system may further comprise a conveyor of a fifth stage, which may run hori- zontally, and which is configured to convey the toilet waste from the conveyor of the fourth stage to a tank or a composter of the processing stage. Thus, the tank or composter may comprise an opening at the top, that is, the inlet of the tank, config- ured to receive the toilet waste from the conveyor, for example via a funnel. In this case, the receiving tank may operate by gravity, and separate conveyors are not necessarily needed within it. Optionally, a conveyor, such as a conveyor of the third, fourth or fifth stage, may be configured to convey the toilet waste to an opening by the side of the receiving tank, acting as the inlet for the tank.

In general, any conveyor of the second stage or a subsequent stage in the system may run in a horizontal, inclined or vertical direction, as needed, or it may be installed in said direction or substantially in said direction. Any of the conveyors may be configured to separate the liquid contained in the toilet waste, for example via one or more holes in the bottom of the conveyor, or via a perforated section, as described above for a vibrating conveyor. The separated liquid may be recovered by means of a collector, pipe or pipeline configured to receive it, and conveyed fur- ther, for example to a tank or to further processing, as described herein. In particular, the conveyors between the toilet units and the composter are encapsulated.

The conveyor or conveyors are normally configured to convey toilet waste in the direction in which the material is processed, that is, from one or more starting points to an end point, for example from one or more waste receiving units, such as toilet units, to waste processing and further to the discharge of the processed waste from the system. A conveyor may not be necessary at absolutely every stage, because the waste may also proceed from one stage to another by gravity or another mech- anism, particularly in waste processing and after that. The starting point or points and the end point are normally located in different places, e.g. in different facilities. Preferably, the material does not proceed in a direction opposite to the processing direction at any stage.

The toilet system comprises a composter having an inlet and an outlet, the inlet being sealed to at least one conveyor for toilet waste, which may be any of said conveyors of the first to fifth stages, and the composter is configured to receive the dry-toilet waste form said at least one conveyor. Other parts of the system may also be provided between the conveyor and the composter, such as a processing tank. The composted material is configured to exit or to be removed from the outlet of the composter.

The composter used in the system is preferably an automated composter, such as an electronically controlled automated composter. The automated composter may be programmed/programmable and/or adjusted/adjustable to produce one or more functions, variables or the like, presented herein. The composter may be encapsu- lated, whereby the encapsulation may incorporate the sensors, processing means, actuators, heater(s), electronics, or the like, relating to the composter. The encap- sulated composter may be movable, for example in a processing room or another space, whereby it may comprise rollers, wheels, or other devices facilitating move- ment. By using the automated composter, it is possible to provide very efficient corn- positing on site and a desired end result, irrespective of the ambient conditions, such as the temperature, moisture content, or the like, or the composition of the material to be composted, and thus it is also possible to electronically control and monitor the operation of the whole system. In particular, a safe process can be provided, which produces hygienic material, whereby the spread of diseases is avoided. Using the automated composter makes this possible, irrespective of the type of toilet units used in the system. Furthermore, the quality of the end product may be secured in advance, before it is passed on.

The volume of the waste can be reduced considerably, for example by 80 to 90%. The automated composter also makes it possible to automate the whole system, either in whole or in part. The automated composter may be run in batch operation or continuous operation. The automated composter may be configured to compost material for a sufficient time to obtain the desired volume, or reduction in volume, of the material composted/to be composted, the desired processing time, the desired temperature, the desired composition of the material composted/to be composted, or another desired end result, or one or more measurable variable, for example as presented in this application.

The automated composter may be configured to control the temperature, moisture content, pH or mixing of the compost or the compost tank; the movement and/or proceeding speed of the material to be composted; the quantity of the material to be composted; and/or the addition, dosage and/or removal of one or more substances into or from the tank, or into or from the compost. The control may refer to the meas- urement of one or more variables in the system affecting the subject to be controlled; and/or performing one or more functions to influence the subject to be controlled, preferably in response to said one or more measurements, for example the meas- urement of the temperature and its adjustment by one or more temperature adjust- ing devices; and/or the measurement of the moisture content and its adjustment by one or more such adjusting devices and/or actuators which may influence the mois- ture content, such as a fan, a heater, a cooler, a mixer, an actuator configured to add or remove liquid or gas, and/or another actuator or function, directly or indirectly. The control may also refer to the mixing of the material to be composted, to provide an even distribution of the temperature, liquid, gas, pH, or another variable or sub- ject in the material. The material may also be subjected to mechanical treatment for pressing out and removing liquid from it by one or more mixer, conveyor, transfer device, or other mechanical device presented herein. The temperature adjusting device may comprise one or more heating elements or cooling elements, and/or one or more fans. The temperature adjusting device may be, for example, electronic and/or based on liquid circulation. The automated composter may be configured to control one or more subjects presented herein, to reach a desired time and/or a desired result. Correspondingly, the processing tank optionally connected to the composter may be equipped with one or more devices and/or functions described in connection with the composter.

In an embodiment, the composter comprises one or more sensors, such as electrical sensors, for detecting the temperature of the compost, connected to one or more control units; and means for controlling the temperature, such as one or more heat- ers or coolers, connected to one or more control units; wherein, in response to one or more values measured from the system, the control unit is configured to adjust the means for controlling the temperature, to achieve the desired temperature in the compost. Temperature control for achieving the desired temperature may be per- formed for a desired processing time.

The composter comprises at least one tank which may be thermally insulated. The composter may comprise one or more mixers for mixing the material to be corn- posted. The composter may comprise one or more sensors, such as an electrical sensor, for detecting the temperature, moisture content, pH, the quantity of material to be composted, gases, or other substances in the compost. The sensors may be connected to one or more control units or other data collecting units, in a wired or wireless manner. The composter may comprise means for transferring material to be composted to, in and/or from the composter, for example one or more mechani- cal means, such as blades, screws or corresponding conveyor solutions, connected to an actuator. These may be operatively connected to one or more control units. For example, the composter may comprise means for removing liquid, solids and/or gas, such as an opening, a valve or the like, which may be operatively connected to one or more control units, wherein the opening, valve or the like can be controlled by the system, wherein the system may control the removal or discharge of the liq- uid, solids and/or gas from the composter by opening and closing the means. The discharge of the liquid, solids and/or gas can also be influenced by one or more mixers in the composter, or by one or more means for moving material into, within and/or from the composter, which means may, for example, compress and/or mix the material and facilitate the separation of liquid, solids and/or gas.

The composter may comprise means for processing the compost, such as one or more mixers; means for adding one or more substances, such as a liquid, for exam- pie a chemical, a dry substance, such as bedding material and/or an accelerant; and/or means for controlling the temperature. One or more of said substances may be added to the composter for controlling the composting, for example in response to one or more values measured from the system.

In an embodiment, the dry toilet system comprises a processing tank which is placed upstream of the composter and which may be thermally insulated, and which corn- prises an inlet and an outlet, the outlet being sealed to the composter, and which tank comprises means for pre-processing the toilet waste, such as one or more mix- ers; means for adding one or more substances, such as a liquid, a chemical, bed- ding material, and/or an accelerant; means for removing liquid, solids or gas, and/or means for controlling the temperature. The processing tank may also be called a pre-processing tank, and the respective stage may be called pre-processing. The inlet of the processing tank is sealed to the conveyor of the preceding stage, which may be any of said conveyors of stages 1 to 5. Thus, the inlet of the composter is sealed to at least one conveyor of toilet waste, via the processing tank. The pro- cessing tank may also comprise one or more sensors, such as an electrical sensor, for detecting the temperature, moisture, pH, material content, gases, and other sub- stances in the toilet waste or the material to be composted. These sensors may be connected to one or more control units as well. The processing tank may comprise means for transferring toilet waste or material to be composted into, in and/or from the container, such as one or more mechanical devices, such as blades, screws or corresponding conveyor solutions, connected to an actuator. These, too, may be operatively connected to one or more control units. The processing tank may be placed above the composter, in which case there is no separate conveyor between them. Alternatively, a separate conveyor or another device or mechanism for trans- ferring material may be provided between them, for example if they are placed side by side.

The processing tank may be configured to process the toilet waste to a desired state, for example to have a desired moisture content, temperature, composition, or pH. The processing tank may comprise, for example, means for removing liquid, such as an opening, a valve or the like, which may be operatively connected to one or more control units, wherein the opening, valve or the like is controllable by the system, wherein the system can control the removal or discharge of liquid from the processing tank, by opening and closing the means. The separation and/or removal of liquid can be influenced by one or more mixers in the container, or by one or more means for transferring the compostable material to, in and/or from the container, which may, for example, compress and/or mix the material and facilitate the sepa- ration of liquid. Removal of liquid may be necessary, if the toilet waste has an exceptionally high content of liquid, for example urine, or if it contains other liquid, such as water. The toilet waste may also be mixed and/or incubated with given additives before the actual composting, for example with a compost starter or accel- erator, bedding material, or another substance. In addition or as an alternative, additives may be added in the composter.

Means for adding one or more substances, for example into the processing tank or composter, may comprise a hole, a valve, or the like, for example above the pro- cessing tank or composter, wherein the hole, valve or the like is controllable by the system, wherein the system can control the addition of the substance by opening and closing the means. The means may also comprise a tank for the substance to be added, from which the system can dose the substance. The tank may be placed, for example, above the processing tank or composter, wherein the substance may run through the opened hole, valve or the like, by gravity. The means may also comprise a conveyor for the substance, such as a screw, a blade or the like, which is controllable by the system and by means of which a given amount of the sub- stance can be added, particularly in the case of solids. The tank for the substance to be added may comprise a lid or the like for closing the tank from the outside, particularly a sealed lid. The tank for the substance to be added may also be sepa- rate from the processing tank or composter, for example in a space that is better accessible in view of maintenance, and it may be connected to the hole, valve or the like by a pipe or a conveyor.

In the system, the means for adding a liquid may comprise a pipe or another duct conveyed from a tank or another liquid source, possibly a valve for adjusting the dosage of the liquid, which valve may be manually or electrically operated. An elec- trically operated valve may comprise an actuator which controls the opening and closing the valve and is connected to one or more control units. The dosage of liquid may be automated so that in response to one or more values measured from the system, the control unit is configured to dose a predetermined or calculated amount of a given liquid into the system, for example into a processing tank or composter. The means for adding dry solids in the system may comprise an openable and clos- able valve, baffle or the like, which is configured to supply the dry solids from a container to the target, for example from a dry solids container placed above the target, such as the processing tank or composter; or the means may comprise a conveyor, such as a screw container, configured to supply dry substance from the container to the target. The means for adding dry solids may comprise an actuator which controls the opening and closing of the valve, baffle or the like, or the opera- tion of the conveyor, and which is connected to one or more control units. The dos- age of dry solids may be automated so that in response to one or more values measured from the system, the control unit is configured to dose a predetermined or calculated amount of desired dry solids into the system, for example the pro- cessing tank or composter. In an embodiment, the dry toilet system comprises means for recovering heat and/or one or more substances from the composter and/or the processing tank. Recover- able substances may include, for example, one or more liquids, solids and/or gases, such as water, one or more nutrients, one or more organic or inorganic substances, carbon dioxide, or microbes. For example, organic or inorganic compounds or fibers may be recovered, to yield material which can be used, for example, as a fertilizer. In general, liquids may be recovered and submitted to further processing.

The system may comprise one or more fittings connected to or opening into a toilet unit, conveyor, processing tank, composter, pipeline, and/or another suitable part of the system, for enabling the functions described herein, for example an inlet or outlet for adding or discharging substances, a fitting for a sensor, a fitting for an actuator and/or its wirings, a fitting for a pipe, or the like.

Furthermore, the toilet system may comprise a tank for the end product, which may be sealed to the outlet of the composter. The tank for the end product may also comprise sensors corresponding to those in the composter, for example one or more sensors for detecting the temperature, moisture content, pH, and quantity of corn- posted material, gases, and other substances. These sensors may be connected to one or more control units as well. The tank for the end product may comprise means for transferring the composted material into, in and/or from the tank, such as one or more mechanical means connected to an actuator, such as blades, screws, or cor- responding conveyor solutions. These may be connected to one or more control units as well. Between the composter and the end product, yet another conveyor may be pro- vided, which may be, for example, a conveyor of a sixth stage, and which is config- ured to convey the composted material from the composter to the tank for the end product. This conveyor may also be similar to or different from a conveyor of a pre- ceding stage. Preferably, all the conveyors in the system are encapsulated, and the encapsulations are sealed to each other or to said containers, to keep the system closed. Instead of the tank for the end product, the toilet system may comprise an outlet, such as a pipe, which may be connected to a bag or a corresponding receptacle for receiving the end product. Correspondingly, the outlet may discharge to another receptacle, such as a platform or the like. The outlet may be equipped with a baffle or another closing device which is only opened when needed, for example for dis- charging the end product from the system. A collector for the end product may be connectible to the end of the outlet, for example a bag at the end of a discharge pipe.

Joints between components of the toilet system, particularly joints relating to the conveying of toilet waste, or joints relating to the conveying of material to be corn- posted or material already composted, are sealed, for example substantially in an air-tight or gas-tight manner, to prevent odour problems, leaking of waste out of the system, or access of external microbes into the system. For example, elastic sealing materials may be used for the sealing, such as rubber or silicone gaskets, sealing putty, gasket tape, or the like. The components of the system are preferably designed to fit as tightly as possible. In an example, the components of the system are not detachable from each other, particularly not during the use.

In an embodiment of the system, the dry toilet system comprises means for applying a vacuum in the system, for example a vacuum pump. In an embodiment of the method, a vacuum is applied in the system. The vacuum may be configured to be applied at least upstream in the system, to prevent the rising of odours from the toilet units to the toilet room. A vacuum may be configured to be applied, for exam- pie, in and from the composter, or downstream the composter in the material flow direction, for example at least from the toilet units to the composter, whereby the vacuum draws air through the compost/composter, whereby active aeration of the compost is achieved. Air intake in the system is preferably via the toilet units, such as via the toilet bowls, and if the toilet units are placed in separate cubicles, each cubicle may be provided with a separate intake for replacement air, for example in the ceiling. Consequently, the toilet cubicles do not have to extend up to the ceiling of the toilet room. An air supply pipe may be connected to the ceiling of the toilet cubicle, for example from the ceiling of the toilet room, whereby air is taken in directly from the outside. This helps to reduce local odour problems. The vacuum or its source may be arranged in a given location in the system, by providing a vacuum pump, or more precisely its inlet, in said location, for example downstream of the outlet of the compost. The vacuum pump may be configured to pump air drawn by it via the outlet of the vacuum system to the outside of the toilet system, for example to the roof of the toilet system in a building or a movable container, or to another location where it causes as little odour problems as possible. Alternatively, instead of a vacuum pump, a fan/air extractor may be used, which is configured to provide an air flow in a given direction in the system, for example in the direction of the material flow.

In general, the aeration of the compost may be arranged to be active or passive. In passive aeration, the flow of air is not boosted, whereas in active aeration it is boosted, for example by exhaustion, for example by applying a vacuum, or by blow- ing air through the compost, for example mechanically, as presented above. Active aeration can be divided into negative and positive aeration. In negative aeration, air is drawn through the compost, normally from the surface through the compost, by applying a negative pressure, that is, a vacuum. In positive aeration, air is blown through the compost. In principle, either method can be applied in the present sys- tem, depending on whether an extractor or a fan is used.

The toilet system may comprise one or more sensors in one or more locations of the system, the sensors being configured to detect one or more of the following: presence of a user, surface level, temperature, moisture content, carbon dioxide content, oxygen content, pH, air flow rate, liquid flow rate, material propagation rate, material quantity, for example in a container, content of a substance, such as ammonia or urea, state of an actuator or a mechanism connected to it, such as rotation speed, and the like, the sensor(s) being coupled, in a wired or wireless manner, to one or more devices configured to receive the detected information. The sensor may also be an optical sensor or camera, by which the operation of the sys- tem can be monitored in one or more locations of the system described herein. This device, or one or more other devices, are configured to process information and to control the toilet system on the basis of the information in order to achieve or main- tain a desired function of the system, for example an optimal composting efficiency, a given temperature, a given composition of the end product, a given processing time, or the like. These devices may be called one or more control units. The control unit may comprise one or more units, such as separate devices, and it is configured to process data in a predetermined way, such as in a programmed way. The control unit may comprise one or more processors, a memory, a user interface, a display, a keypad or a touch screen, a power connector, one or more physical connectors and/or wireless connection means for connecting to sensors and/or other external devices, for example a wired or wireless network connection. The control unit may comprise one or more computers and/or an embedded system. The control unit may comprise software which is configured to perform one or more control functions, such as to control and run one or more devices connected to the control unit. The actuators connected to the system may be operatively connected to one or more control units, which means that the control unit may run the actuators. The control unit may be coupled to one or more actuators or other devices whose operation has an effect on the state and/or running of the system, such as the pumps, fans, valves, baffles, mixers, conveyors, heaters, coolers, and the like, described herein. An actuator may comprise, for example, one or more electric motors, such as a rotating or linear electric motor, servo motor, solenoid, hydraulic or pneumatic motor or cyl- inder, or combinations of these. Preferably, the actuator is electronic and/or elec- tronically controllable. A mechanism means connected to an actuator may produce a mechanical motion, for example apply a valve or mix, or, for example, heat. The mechanism may have an effect on a manipulated variable in the process, such as the temperature or the flow of a liquid, gas, electricity, or another flow.

By controlling the operation of these devices, it is possible to achieve or maintain the desired operation of the system, for example by the actions described herein. The desired operation may be to reach and/or maintain a predetermined value, for example to maintain a given variable, such as the temperature, moisture content, pH, dry solids content, the content of a given substance, or the like, within reference values.

The control unit and the sensors and devices connected to it constitute a control system which may be implemented in the physical facilities of the toilet system, for example in a movable container. The control system comprises the necessary wir- ings between the different devices and/or the necessary devices of a wireless net- work for setting up the connections between the devices, as well as other possible switches, control devices, actuators, connectors, adapters, transformers, or the like, which are necessary for the system to operate. In general, any device of the toilet system, whose operation can be controlled and monitored, may be connected to the control system and configured to be controlled and/or monitored by it. The control system may be remotely connected to an external system or user, for example in a wireless manner, whereby it is possible to remotely monitor the operation of the system, to obtain data on it such as function reports, and possibly influence the operation of the system. The collected data can be compiled in a written document, for example for the authorities. Primarily, however, the system is designed to oper- ate as independently and automatically as possible, whereby it does not necessarily require external action.

Disclosed is also a movable container comprising a closed dry toilet system as described herein. The movable container may be any suitable freight transport con- tainer which can be moved by a transport vehicle or from one transport vehicle to another without reloading the contents. It may be a transport container such as a container used in transport by road, rail, air, or sea. The transport container may be made of a metal, such as steel or aluminium, or a composite material, plastic, wood, or another suitable material. The most common container type is the so-called ISO container defined and classified by the international standardization organization (ISO). It is the most common transport unit worldwide, and inexpensive, due to mass production.

The toilet system presented herein is particularly well suited to be built up in a con- tainer. Because there is no need for a separate sewage system or another pipeline which would take space in the vertical direction, the toilet system can be built in a single level and fitted in a container. A required number of containers can be pro- vided and transported to a target site to cover the toilet capacity needed. When the container is placed at the site, the toilet facility is ready for use without any construc- tion measures or the like. There is no need for plumbing, because the system yields hygienized toilet waste and substantially clean water. The dry toilet system fitted in the container has a high capacity. If necessary, the container can be connected to an external power source to provide power for the devices of the system and, for example, for lighting, but the system may also be constructed to be self-sufficient with respect to electricity; for example, it may comprise a system of batteries which may be pre-charged and/or which may be charged by solar energy, wind power, and/or thermal energy obtained from the system. Correspondingly, the system may comprise one or more solar panels, a wind power plant, or a generator powered by thermal energy, or the like. Disclosed is a method for processing toilet waste, the method comprising

- providing a closed dry toilet system or a movable container, as described herein,

- composting toilet waste accumulated in a composter for a sufficient time for hygienizing the toilet waste, to obtain processed toilet waste.

The method for processing toilet waste yields processed toilet waste which is hygienized. The processed toilet waste meets the standards EC 1069/2009 and 142/201 1 . In an embodiment, the hygienized toilet waste is transferred to a tank for the end product. The process can be run in batch operation or continuous operation. Preferably, the process is continuous. This reduces or eliminates the need for maintenance, emptying, or other operations during the use, which might deteriorate hygiene, impair the operation of the system, and/or cause interruptions in use. How- ever, such measures have to be taken at times. For example, approximately once a week the composter may need to require a load break of about 24 hours, including hygienization at the end.

The dry toilet system, or the transport container comprising it, is provided for use at a desired location, as described herein. The system is built up in, for example, a suitable space in a building, or the facilities are constructed separately, for example the walls, ceiling, and/or the floor. Alternatively, one or more transport containers are brought to the site and placed in a suitable location, for example on flat ground or on another suitable base. If the system requires external power, it is connected to such. The control electronics of the system is switched on, if necessary, and the system is ready for use. Users of the toilet system produce toilet waste which is conveyed by the system, via possible pre-processing, to composting in a composter.

The toilet waste is composted in the composter at a temperature higher than, for example, 40°C. In an embodiment, toilet waste is composted in the composter at a temperature higher than 50°C, or at a temperature higher than 55°C. In a particular embodiment, toilet waste is composted in the composter at a temperature higher than 60°C, even higher than 62°C or 65°C, to secure the elimination of particularly pathogenic microbes. In many cases, even a lower temperature is sufficient, such as said temperature higher than 50°C or 55°C. A majority of the most common path- ogens are destroyed relatively rapidly at temperatures from 50 to 60°C, even within minutes or hours. If higher temperatures are to be used, it may be necessary to make sure that the composting process itself works at said temperature. Many con- ventional composting microbes may be inactivated at high temperatures, such as mesophilic microbes active in composts, whereby it may be necessary to add one or more different thermophilic microbes in the system. A thermophilic microbe refers to a microbe which is viable and/or maintains at least part of its activity, such as composting activity, at a desired temperature, for example at temperatures from 40 to 70°C. Tests showed that the temperature within a composter is normally between 40 and 55°C, and during hygienization, higher than 70°C for two hours. Thermophilic microbes may be supplied as a particular compost accelerator which may also con- tain other components. For example, an accelerator composition may be provided which contains a microbial composition combined with a natural fibre material, such as a plant-based, for example cellulose-based, fibre material. The microbial compo- sition may be selected to boost the composting of toilet waste and, for example, configured to provide a composting temperature presented herein, or another desired condition in the compost. Combined with a natural fibre material, the micro- bial composition improves the distribution of the accelerator composition in the material to be composted, and the fibre material may act as a supporting material to improve the preservability and viability of the microbes, and/or to provide nutrients which boost the composting, particularly the starting of the process.

The composter may be configured to compost or process toilet waste collected in the composter normally at a temperature higher than 35°C, preferably at a temper- ature of 40°C or higher, such as 50°C or higher, or 60°C or higher, normally for a sufficient or desired processing time. The suitable composting temperature may range, for example, from 40 to 70°C, from 40 to 65°C, from 40 to 60°C, from 40 to 55°C, or from 40 to 50°C, depending on e.g. the composition of the material to be processed, the microbes used, or another factor relevant for the composting or the end result. The processing time taken for the composting or processing may range, for example, from 2 to 48 hours, such as 6 to 40 hours, 12 to 48 hours, 6 to 24 hours, 12 to 24 hours, 24 to 48 hours, or 20 to 30 hours. This is the retention time of the material in the composter or its tank. The composter or system may be configured, or it may be set or programmed, to provide one or more temperatures and/or com- posting/processing times, or other variables, presented herein.

In an embodiment of the method, one or more substances are added to the toilet waste, such as a liquid, for example water or urine, or a dry solid substance, such as bedding material, and/or a compost starter or accelerator, for example into the processing tank or the composter. In an embodiment of the method, a thermophilic accelerator is added to the toilet waste, for example into the processing tank or composter. The adding may be automated, wherein a control unit controls an actu- ator which performs addition of the accelerator to a given point in the system, such as the processing tank, one or more of said conveyors, or the composter, for exam- pie by means of a valve or the like connected to the actuator, from a reservoir.

Achieving the desired temperature involves a plurality of factors, such as the micro- bial strain used, the composition of the material to be composted, the moisture con- tent of the compost, etc. Normally, an efficient composting process provides the required temperature as such. By and large, the temperature of the compost may range from about 30 to 70°C, or from about 40 to 70°C. However, to boost compost- ing and to achieve efficient hygienization of the end product, it may be desirable to keep the temperature of the compost in the range of 50 to 70°C, 55 to 70°C, 60 to 70°C, 62 to 70°C, or 65 to 70°C. One or more measures mentioned in this context may be taken to keep the temperature of the compost in the above mentioned range.

The time sufficient for hygienization may depend on the conditions, the starting materials, the substances to be added, and other factors. A sufficient time may be, for example, 2 to 34 hours, when a thermophilic microbial strain is used.

In some examples, for hygienization of toilet waste in a separate hygienization step, a relatively high temperature may be applied, such as about 65°C, about 70°C, or about 75°C, for example a temperature of 65°C or higher, 70°C or higher, or 75°C or higher, for 1 to 6 hours, for example for about two hours, or at 75°C for about one hour. Normally, the temperature does not exceed 80°C at any stage, wherein the temperatures used in the method are preferably in the range of 80°C or lower, 78°C or lower, or 75°C or lower. Hygienization may be performed, for example, in a tem- perature range of 65 to 80°C, 70 to 80°C, 65 to 75°C, 65 to 78°C, 70 to 78°C, 70 to 75°C, or 75 to 80°C, for example for 1 to 6 hours, such as for 1 to 3 hours, or for 1 to 2 hours.

To enable the compost to work well, it has to have an appropriate balance of carbon, oxygen, nitrogen, and water. Composting is efficient when the carbon to nitrogen ratio is in the range between 10: 1 and 20: 1 . The material to be composted contains toilet waste, but since the composting process requires aerobic conditions, it may be necessary to add bedding material or the like as well, to secure aeration of the material to be composted, particularly if the material has a high moisture content. The negative pressure created in the system provides active aeration which helps to maintain aerobic conditions, and the negative pressure may also be controlled to achieve or maintain a desired aeration rate for controlling the composting process. To provide or contribute to the aeration, it is also possible to apply mechanical mix- ing, for example rotating blades, in the composter. Anaerobic conditions should be avoided, because anaerobic digesting reactions are the principal reactions under anaerobic conditions. These reactions, in turn, cause odour problems and, for example, methane emissions.

Normally, there is no need to add water in the compost, because in the decomposi- tion process, water and heat are released from the material to be composted. Most of the water is released in the form of vapour, and the oxygen is rapidly used up in the process. However, the quantity of vapour released from the biomass is high, whereby it may be necessary to control and adjust the process. The ratio between water and air has a great effect on the temperature of the compost, so that to main- tain a high temperature, there may be a need to optimize these variables. At times, it may be necessary to adjust the moisture content of the compost by adding liquid, such as water condensate or other water. In particular, a sufficient moisture content may be required for starting hygienization. At least part of the urine and/or other liquid collected in the toilet system can also be conveyed to the compost, whereby it can be composted as well, or it is possible to affect the properties and performance of the compost and the composting process. Liquid can also be added to influence the temperature, for example to increase or decrease it, depending on the temper- ature of the liquid. For example, it may be a better alternative to decrease the tem- perature of the compost by means of a liquid than by means of air, because the liquid does not contain free oxygen which would accelerate the composting process and increase the temperature further. The moisture content in the compost or pre- processing may also be influenced by adding a dry substance, such as bedding material.

The temperature of the compost may also be adjusted by means of air, for example directly by means of the temperature of the air, whereby the compost can be heated or cooled by blowing or drawing hot or cold air, respectively, into or through the compost. The flow of air may also be applied to adjust the temperature indirectly, because a higher air flow rate will boost composting and cause a rise in the temper- ature, whereas reducing the air flow rate may slow down the process and decrease the temperature. The air flow rate can be adjusted by controlling a vacuum pump or another air pump or fan in the system. These devices may be connected to one or more control units, whereby in response to one or more values measured from the system, the control unit is configured to control the operation of the device having an effect on the air flow rate, for example to turn it on or off, or to adjust its speed and thereby to influence the air flow rate. The composter may also comprise one or more heaters or coolers which may be used for adjusting the temperature accord- ingly, and which may be connected to one or more control units, whereby in response to one or more values measured from the system, the control unit is con- figured to control the heater or cooler to provide a desired temperature in the corn- post. Corresponding arrangements may be applied in a similar way to the pro- cessing tank as well.

The liquid to be added may be water, urine, or conveyor washing liquid, or a corre- sponding aqueous liquid. The bedding material may comprise plant based material, such as wood based material. The bedding material may be provided in the form of pellets, chips, mulch, or the like. A required quantity of these may be added to achieve a desired ratio between the material to be composted and the bedding material. Bedding material may also be added to adjust the moisture content of the compost, whereby it is added to achieve a desired moisture content or dry solids content. The bedding material may also reduce odour problems, bind nitrogen and/or phosphorus, and it may accelerate the composting, whereby it may also be added to provide these properties.

In an embodiment of the method, diverted urine is processed to isolate substances contained in it, for example in dissolved or suspended form, in practice from water. The separated substances may be recovered and/or discharged, for example into a tank for the end product. The urine may be processed, for example, so that at least part of the dissolved substances is precipitated, for example by adding one or more precipitating agents or by adjusting the temperature. The substances contained in the urine, such as precipitated and/or suspended substances, can be separated e.g. by filtration. The urine may also be circulated via a cooling system or a heating sys- tem. Such a system may be a separate apparatus which may be electrically pow- ered. The urine may also be heated by conveying it through the composter, for example via one or more pipes in the composter, whereby the relatively high tem- perature of the composter is sufficient to heat the urine. By the same principle, another liquid may be heated, for example water, such as washing water for use in the toilet. In an example, the composter thus comprises one or more heat conduct- ing pipes and/or a heat exchanger connected to the pipeline via which the external liquid is configured to flow. In this way no separate heaters are needed for heating liquids, and energy is saved. By the same principle, liquid can be circulated through the composter and used for heating the toilet facilities. The liquid circulations needed in the system may be arranged by applying one or more pumps, such as a circulator, which may be electrically powered. One or more pumps may be connected to one or more control units which are arranged to control the pumps, for example in response to one or more values measured from the sys- tem, and/or a pre-programmed action.

In an embodiment of the method, heat and/or one or more substances, such as one or more organic or inorganic compounds, are recovered from the composter. The heat may be recovered from the composter, as described above, or it may be recovered from another point in the system, such as from the processing tank or the air flowing in the system. The heat may be recovered by means of a heat exchanger, and it may be transferred to a liquid, or it may be recovered in the form of warm or heated air. For example, the obtained liquid may be used for heating a part of the system, or air. The heat may be used for heating the toilet facilities, for example, by blowing heated air, or by circulating heated water through one or more heat exchangers, such as heating radiators.

Substances to be recovered may include, for example, organic or inorganic corn- pounds containing phosphorus, nitrogen and/or potassium, such as various nitro- gen, phosphorus or potassium compounds.

An embodiment of the method comprises

- detecting one or more properties of the system, such as temperature, pH, carbon dioxide content, and/or moisture content, at one or more points in the system; and

- in response to the detected properties, taking actions in at least one location to influence the temperature or the pH in the system, the temperature and/or moisture content of the material to be composted, the speed of propagation of toilet waste in the system, and/or the dosage of a liquid or dry substance. The action may have an effect on a detected property and/or another property.

Example

Example 1.

In an example (Figs. 1 a and 1 b), a closed dry toilet system is implemented in a BM30 container 30 whose outer dimensions are 9.120 m ^c 2.435 m ^c 2.591 m. The container is divided into a toilet compartment 32 and a toilet waste processing com- partment 34, which are separated from each other by a wall. Furthermore, the toilet compartment is divided into two parts, men's 35 and ladies' 36 rooms, which are separated from each other by a wall. The ladies' room comprises five dry toilet bowls 10 provided with seats, and the men's room comprises three dry toilet bowls 10 provided with seats, and three urinals 12. The toilet bowls with seats are each placed in a separate cubicle equipped with a door and an air intake in the ceiling, connected by pipes to an air intake in the middle of the roof of the container; and the urinals are separated by walls. Each room is equipped with a wash-hand basin 1 1 , 13, to which water can be supplied from a water tank on the roof. The dry toilet bowls equipped with seats are installed on top of two conveyors 14a, 14b of the first stage, the conveyors being configured to be actuated when a dry toilet bowl connected to them is used. The conveyors 14a and 14b are spiral conveyors having a length of 9 m and 2 m, respectively, and a diameter of 125 mm, and they are encapsulated in U-shaped encapsulations having a size of 200 ^c 200 mm which are sealed to the toilet bowls 10, as shown schematically in Fig. 2c. The toilet waste is conveyed by the conveyors 14a, 14b of the first stage to a conveyor 15 of the second stage, having a length of 3 m and being perpendicular to the conveyor of the first stage. From the conveyor 15 of the second stage, the waste is transferred to the toilet waste processing compartment 34 behind the wall. The processing compartment comprises a Green Good composting machine 20, a tank 22 for the end product, and a pre-processing tank 18 placed on top of the composter. The waste is trans- ferred to the top of the pre-processing tank by means of a conveyor 16 running at an angle of about 45 degrees and having a length of 3.5 m (horizontal run about 1 .5 m) and a conveyor 17 running in the horizontal plane (about 1 .5 m).

The waste is transferred to the pre-processing tank 18 via an inlet and a funnel at the top. From the pre-processing tank 18, the waste is transferred by gravity to the composter 20 down below. From the composter 20, the composted toilet waste is transferred, as the end product, by a discharge conveyor 19 having a length of 1 m, to a storage tank 22 which is placed next to the doors 36, 38 of the openable rear wall of the container 30 and which can be emptied through them.

The drain holes of the urinals 12 in the men's room 35 and of the wash-hand basin 13 in the ladies' room 36 are connected to the pipe 23, and the drain hole of the men's wash-hand basin 1 1 to the other pipe 25, correspondingly. The pipes extend to the processing compartment 34 where they are joined and conveyed to a urine collection tank 24.

Running-in of the process Initial analyses and tests were conducted for adjusting the system to be suitable for each waste type. Composting process

The actual composting took place in an automated Green Good machine corn- poster. The conditions of the composter are optimized, whereby a natural compost- ing process was carried out in about 24 hours. Finally, the mass was hygienized according to EU standard EC 1069/2009. The composting included microbes which are isolatable from the ground and whose decomposting properties were maximized by applying a suitable temperature and mechanical aeration implemented by rotat- ing blades. Running of the process could be monitored by means of measuring devices installed in the composter, whereby e.g. the temperature, pH, carbon diox- ide content, and/or moisture content were measured. The measured variables pro- vided information on the running of the process and, for example, on whether a sufficient temperature and time for hygienization are reached.

In an embodiment, the emptying of the composter is automated. By composting blades or, alternatively, a screw, the produced hygienized mass is pushed via an unloading hatch to a tank for the end product or, alternatively, directly to bulk bags, or onto a platform. At any stage, the mass cannot flow in the wrong direction in the process, because the transport mechanism only works in one direction, and the starting and end points in the process are located in physically different spaces.

Example 2.

A dry toilet system implemented in a container is shown in Figs. 3 to 6. The pro- cessing compartment (Fig. 3) comprises an automated and electronically controlled Oklin GreenGood composting machine which controls e.g. the temperature, mois- ture content, and mixing, as well as hygienization of the compost. The material to be composted is conveyed to the composter from a toilet compartment behind a wall by means of an encapsulated screw conveyor of the second stage. Figure 3 shows the pipe of the screw conveyor rising obliquely from the floor level, and an actuator (electric motor) at the end of the pipe, for rotating the screw conveyor. The screw conveyor is connected to an inlet above the composter, for feeding material into the composter. Urine diverted in the toilet compartment is conveyed to a separate tank (not shown) in the processing compartment along a white pipe extending from the toilet compartment. From the housing of the horizontal conveyor, air is drawn along a grey pipe which is shown underneath the oblique conveyor pipe in Fig. 3.

The toilet compartment comprises several diverting toilet bowls equipped with seats and installed on top of the same encapsulated horizontal screw conveyor of the first stage (Figs. 4 to 6), which is configured to receive and convey toilet waste from the toilet bowls. Figure 4 shows the screw and the shaft of the conveyor, visible through the opening of the toilet bowl, as well as aeration pipes connected to the encapsu- lation of the conveyor. The container comprises separate men's and ladies' rooms, as well as a separate accessible toilet room at the end of the container (Fig. 6). Figure 6 shows an actuator installed at the end of the horizontal screw conveyor, for rotating the screw conveyor. The encapsulation is also provided with an air pipe, via which air can be drawn from the encapsulation of the conveyor by a pump in the processing compartment. A second air pipe is conveyed out of the encapsulation, whereby it can be used as a reserve system for aeration. The pumps, the actuators for the conveyors, and the other actuators are connected to a central processing unit (not shown) placed in the processing compartment and configured to control the system in a pre-programmed way. For example, the actuators for the screw conveyors are configured to start when a motion is detected by motion sensors in the toilet compartment.

The screw conveyor is an advantageous choice, because it can be operated by rotating a shaft at the end of the conveyor, whereby the actuator is outside the encapsulation, and the encapsulation does not need to house any actuators, other parts or couplings, in addition to the screw, which might be easily soiled or damaged. When the screw is placed in a compatible tubular encapsulation, the structure is sufficiently impermeable for conveying the toilet waste in an efficient way, which reduces the accumulation of waste in the conveyor structure.

Claims

1. A closed dry toilet system comprising

- at least one dry toilet unit (10),

- at least one encapsulated conveyor (14, 14a, 14b) for toilet waste, sealed to at least one dry toilet unit (10),

- a composter (20) with an inlet and an outlet, the inlet being sealed to at least one conveyor (14, 14a, 14b, 15, 16, 17) for toilet waste, and the composter being configured to receive the dry-toilet waste from said at least one conveyor, and - optionally a tank (22) for the end product, which may be sealed to the outlet of the composter (20).

2. The dry toilet system according to claim 1 , characterized in that the composter is an automated composter.

3. The dry toilet system according to claim 1 or 2, characterized in that the composter comprises one or more sensors, such as an electric sensor, for detecting the temperature of the compost, connected to one or more control units; and means for controlling the temperature, such as one or more heaters or coolers, connected to one or more control units, wherein in response to one or more values measured from the system, the control unit is configured to adjust the means for controlling the temperature to achieve a desired temperature in the compost, pref- erably for a given processing time.

4. The dry toilet system according to any of the preceding claims, characterized in that the composter is configured to compost toilet waste collected in the composter, preferably at a temperature higher than 40°C, such as higher than 50°C, or higher than 55°C, or higher than 60°C, for a sufficient time for hygienization of the toilet waste, for example in a separate hygienization step at a temperature higher than 70°C for two hours.

5. The dry toilet system according to any of the preceding claims, characterized in that the conveyor (14, 14a, 14b, 15, 16, 17) for toilet waste is installed in the horizontal plane or substantially in the horizontal plane, and preferably selected from a screw conveyor, such as a spiral conveyor, a vibrating conveyor, a belt con- veyor, and a scraper conveyor.

6. The dry toilet system according to any of the preceding claims, characterized in that it comprises a processing tank (18) upstream of the composter, hav- ing an inlet and an outlet, the outlet being sealed to the composter (20), and corn- prising means for preprocessing the toilet waste, such as one or more mixers, means for adding one or more substances, such as a liquid and/or a solid substance, and/or means for controlling the temperature.

7. The dry toilet system according to any of the preceding claims, characterized in that it comprises means for applying a vacuum in the system, such as a vacuum pump.

8. The dry toilet system according to any of the preceding claims, characterized in that it comprises means (48) for separating urine from feces, for example in a dry toilet unit or in a conveyor for toilet waste, and a pipeline for conveying the urine separately, for example to a tank, for example a collection tank and/or pro- cessing tank for urine.

9. The dry toilet system according to any of the preceding claims, characterized in that it comprises means for recovering heat and/or one or more sub- stances from the composter, which substance may be one or more liquids, solid substances and/or gases, for example water, one or more nutrients, one or more organic substances, or microbes.

10. A movable transport container (30), such as a container which corn- prises the closed dry toilet system according to any of the preceding claims.

1 1 . A method for processing toilet waste, the method comprising

- providing the closed dry toilet system according to any of the claims 1 to 9, or the movable transport container according to claim 10,

- composting toilet waste collected in the composter, preferably at a temperature higher than 40°C, such as higher than 50°C, or higher than 55°C, or higher than 60°C, for a sufficient time for hygienizing the toilet waste, for example in a separate hygienization step at a temperature higher than 70°C for two hours, to obtain pro- cessed toilet waste,

- and optionally transporting the hygienized toilet waste to a tank for the end prod- uct.

12. The method according to claim 11 , characterized by providing the sys- tem with a vacuum.

13. The method according to any of the claims 11 to 12, characterized by adding one or more substances into the toilet waste, for example a liquid or a dry solid substance, such as bedding material and/or an accelerator, such as a thermo- philic accelerator, for example in the processing tank or the composter.

14. The method according to any of the claims 11 to 13, characterized by processing the diverted urine for separating substances contained in it.

15. The method according to any of the claims 11 to 14, characterized by recovering heat and/or or one or more organic or inorganic compounds from the composter.

16. The method according to any of the claims 11 to 15, characterized by

- in response to the detected properties, taking actions in at least one location to influence the temperature of the pH in the system, the temperature and/or moisture content of the material to be composted, the speed of propagation of toilet waste in the system, and/or the dosage of a liquid or dry substance.