The invention relates to a composting device for toilet and kitchen waste, which device is to be used in connection with a toilet. In normal use, the toilet and kitchen waste is removed from the device after it has been composted into soil.

In composting toilets, it is a common practice to add additives to the waste contained in a one-part composting container in connection with the filling of the container. These additives make the composting more rapid and alleviate the smell problem. The com¬ post is usually aerated only at the top, and the sur¬ plus liquid remaining after the aeration is discharged directly into the surroundings through small openings formed in the bottom or at the side of the bottom or through a collector pipe. When the composting device is emptied, waste materials composted to different de¬ grees are mixed with each other, whereby fresh, smell¬ ing waste is also removed from the container in con¬ nection with the emptying. The compost cannot be used as plant manure without intermediate storage.

There also exists a rotating composting device in which .a cylindrical inner compost container is positioned within a cylindrical outer container. The compost container is divided into four sections in such a manner that waste materials composted to diffe¬ rent degrees remain apart from each other. The com¬ posting device is positioned below the floor of the toilet room, and a vertical tube projects from it into the toilet room. The toilet seat is positioned at the end of the tube. In this composting device, the waste is aerated only from the top. Surplus liquid flows into the outer container through small openings pro¬ vided in the bottom of the compost container, where-

from it is discharged through a discharge tube pro¬ vided at the side of the container. Only the inner container rotates on a shaft positioned centrally in the container.

A common problem with the first-mentioned com¬ posting devices is that wastes of different degree of composting are mixed with each other in connection with the emptying and/or the composting process is postponed by means of additives so that it takes place after the emptying. The compost to be emptied smells and cannot be used as manure as such.

In the last-mentioned composting device, the composting of waste takes place slowly, as only the top layer of the compact waste material is aerated. Also, the waste is too dry as it does not get any extra humidity when the aeration air flows on the top of the waste layer into the liquid container and out therefrom. Due to the elongated vertical tube with the toilet seat at the top of it, the smell of the compost enters the toilet room as the natural aeration is not strong enough to suck the smell down along the rather long tube. The double container makes the composting device expensive and the container is difficult to empty from the side through a door provided in the double container wall. The compost material easily flows into a gap defined between the containers when the container is being emptied, which later on hampers the discharge of liquid.

A decisive improvement is achieved with respect to the above drawbacks by means of a device according to the invention.

In the device according to the invention, a ro¬ tating compost container is divided into four sections to keep apart compost materials of different degree of composting. After one section has been filled up, the

waste contained therein is covered with a couple of buckets of soil or old compost, and the container is rotated to take a new container section into use. The compost container is positioned partly within the toilet room so that the toilet seat is positioned im¬ mediately or substantially immediately above the cover of the composting device. In this way, no vertical tube difficult to aerate is needed and, as a conse¬ quence, the smell of the compost will not enter the inner room when the lid of the toilet seat is opened.

In the compost container, the waste is aerated both from above and from below as the container is provided with a grate and a floor made of a filtering cloth. The circulation of air is arranged to take place in such a manner that the air flow is all the time natural, that is, takes place in an upward direc¬ tion (the air warms up in the composting device). The air flow causes the liquid on the bottom of the con¬ tainer to evaporate and takes the evaporated liquid with it, thus continuously introducing liquid into the compost material above so that the compost will not get dry. Partition walls provided in the container make the air flow flush the compost material ef¬ ficiently both from below and from the top. The aeration and humidification are made even more effi¬ cient as part of the air flow passes through the com¬ post material.

All of the compost liquid stays for some time in a receiver formed in the bottom of the container, being purified biologically. Thereafter part of the liquid is evaporated and part of it flows away through an opening provided centrally in the bottom of the compost container into a receiver therebelow. In this way, the liquid can be collected at one point by means of a rotating single-wall container, and the high cost

of a double container construction is avoided.

The composting device is emptied from the out¬ side by lifting the emptying door. Since there is no gaps between container walls, the compost material will not clog liquid discharge openings when emptied.

By means of the device according to the inven¬ tion, a decisive improvement is achieved with respect to the above drawbacks. To achieve this, the device according to the invention is characterized by the disclosure of the characterizing portion of claim 1.

A major advantage of the invention is that the composting capacity of a toilet and food stuff com¬ posting device is improved to such an extent that even in a device based on natural aeration, the compost ma¬ terial to be emptied is already in the form of good manure. Furthermore, the smell problems of the com¬ posting device are alleviated, and the cost of manu¬ facture is reduced.

Practical experiments and laboratory tests carried on a prototype of the invention have shown that the invention works well and efficiently as de¬ scribed above.

In the following the invention will be de¬ scribed in detail with reference to the attached draw¬ ings, wherein

Figure 1 shows a composting device when in¬ stalled in place; and

Figure 2 shows a general cross-sectional view of the device of the invention.

Figure 1 shows a composting toilet device ac¬ cording to the invention when installed in place in the wall of a building. A compost container 6 is posi¬ tioned partly outside the building, partly within it in such a manner that a toilet seat 5 is positioned within the building and a ventilation tube 13 as well

as an emptying lid 2 outside the building.

Partition plates 7 are provided within the con¬ tainer 6 so as to divide the container into compart¬ ments. In use, a bed of compost liquid 10 is gathered on the bottom of the container while the proper com¬ post material is gathered on a filtering floor 9. The container 6 rotates on wheels 11.

Figure 2 shows a general cross-sectional view of the device of the invention. Air enters the com¬ posting device through a gap defined between a re¬ ceiver hopper 3 for surplus liquid and the container 6. The air passes around a lower plate 8, entraining liquid from the underside and humidifying and oxidiz¬ ing the compost material on the filtering floor 9 from below. The air passes on in a centrally positioned rising tube 14 below an upper plate 1 which leads the humid air on top of the compost material and further into the ventilation tube through a gap defined be¬ tween the upper plate 1 and the ventilation tube and then out of the device. Part of the air passes upwards through the compost material.

The device according to the invention can also be provided with mechanical ventilation or heating, or additives promoting composting can be used.

The diameter of the lower plate 8 and the upper plate 1 is preferably 1.5 to 3 times greater than that of the rising tube. The cover of the container 6 is detachable so that it can be lifted on hooks fastened to the wall while the container is rotated. Normally the cover of the container 6 is fastened in place by means of a supporting iron 15 and screws 17 provided at both ends thereof. In order to avoid the construc¬ tion of a separate basement for the device, the device comprises a supporting framework 12 for fastening it to the walls of the building on both sides and to the

floor of the toilet room in front of the toilet seat. As distinct from the above, the device can be posi¬ tioned entirely within the building.

In the device according to the invention, it is, of course, possible to use any suitable filtering layer in place of the filter cloth, and various other air flow guide means can be used in place of the upper and lower partition plates. It is likewise thinkable that no separate air flow guide means are required if the composting device is so designed that the air flows as described above.