GB2248641A

GB2248641A - Waste treatment system suitable for use in a passenger vehicle

Info

Publication number: GB2248641A
Application number: GB9114750A
Authority: GB
Inventors: Richard Barton; Jeremy Peter James Edwards
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-10-11
Filing date: 1991-07-09
Publication date: 1992-04-15
Anticipated expiration: 2011-07-09
Also published as: GB2248641B; GB9022144D0; GB9114750D0

Abstract

A waste treatment system suitable for use in a passenger vehicle comprises a mass receiving chamber (2) and a heat exchanger for connection to a work performing system e.g. the vehicle drive source, which generates heat during performance of its work function. <IMAGE>

Description

WASTE TREATMENT SYSTEM This invention relates a waste treatment system, in particular for use in passenger vehicles.

An example of a decomposition toilet is described in WO-A-80/00962 which is incorporated herein by reference.

The toilet described has a-chamber in which decomposable material is heated by an electric heat source to a temperature which provides for decomposition and pasteurization, the pasteurized material being moved away by electrically controlled stirring means. Although such a toilet may be satisfactory for use in a house where there is mains electricity supplied, it would not be satisfactory for uses where electricity is either unavailable or at a premium for example in passenger vehicles such as coaches, boats, ships, trains or aircraft. In these cases space is also at a premium and the provision of a separate electricity supply may not be feasible.

In accordance with the present invention, a waste treatment system comprises a decomposition chamber comprising a mass receiving chamber, and a heat source, the heat source comprising heat exchanging means for cpnnection to a work performing system which generates heat during performance of its work function, the heat being dissipated by transfer to a fluid; the heated fluid being fed to the heat exchanging means to provide the heat source with heat.

This invention provides a waste treatment system which can be used in a vehicle without needing its own auxiliary power supply or taking up excess space. The treated waste may be sold or otherwise safely disposed.

The heated fluid may comprise water from a cooling system of vehicle, boat, ship, train or aircraft drive means; lubricant from a lubricating system of the drive means of a vehicle or aircraft; or exhaust gases; all of which have been heated for other reasons. Preferably, the heat is waste heat from sources such as described above, although heated water from a system provided to heat the engine or vehicle in cold conditions may be used.

The work performing system could also be an air-conditioning system from which heated air or liquid is fed to the heat exchanging means.

The decomposition chamber of the waste treatment system is preferably separated from the work performing system. Where the decomposition chamber forms part of a decomposition toilet in a passenger vehicle the toilet is preferably positioned in a separate ablutions area; and this area is typically separated from passenger accommodation by at least one wall.

In one example the heat source heats the decomposition chamber. In other examples, the heat source heats air supplied to the decomposition chamber.

Two examples of waste treatment systems in accordance with the present invention will now be described with reference to the accompanying drawings in which: Figure 1 is a vertical section through a first example of a decomposition toilet; Figure 2 shows the arrangement for direct heating of the chamber of the toilet in Figure 1; Figure 3 shows the arrangement for heating the chamber of the toilet of Figure 1 via a heat exchanger; Figure 4 is a detailed view of a heat exchanger in the motor coach of Figure 2; Figure 5 is a schematic side view of a motor coach provided with the decomposition toilet of Figure 1; and Figure 6 is a block diagram of the heated fluid control means; and, Figure 7 is a schematic diagram of a second example of a decompostion toilet.

An example of a decomposition toilet is shown in Figure 1. There is a chamber 2 containing stirring means 3 to stir the decomposable material 4 after it enters the chamber 2. Stirring means 3 are rotatably mounted to a shaft 5. The normal direction of rotation 6 is reversable to a new direction 7 to enable the treated decomposable material to be moved away from the bottom of the chamber towards an opening 8 where the material falls down into a collection chamber 9.

While the material remains within the chamber it is heated to between approximately 450C to 800C (the thermophilic temperature range) in order to pasteurize the material. The heat supplied to the bottom 10 of the chamber 2 is from a water jacket 1 which covers the outer side of the bottom of the chamber. Between the bottom 10 of the chamber 2 and a wall of a unit 11 containing the chamber is provided insulation 12. The unit 11 is made of non-corrodable material.

In the example of Figure 2, the heat source is waste cooling water supplied directly to the water jacket 1. To control the heating, the supply of cooling water to the water jacket 1 is cut off or permitted to flow according to the position of a valve 25 controlled by an electrical control circuit. Shut off of the heated water occurs when the temperature of the chamber 2 reaches an upper temperature boundary (approximately 70"C) as measured by a themostat 29; and when the temperature has dropped to approximately 500C then the flow of waste coolant water will return to the water jacket 1 and heat the chamber once more.

In a second example (Figure 3) the water in the water jacket 1 is heated by exhaust gases via a heat exchanger 17. A flow of water is provided circulating from an input 30 over the heat exchanger to an output 31 which is connected to the water jacket 1. As heat is transferred to the chamber the water flowing cools and is returned to the input 30 to be reheated. An electrically controlled valve 25 diverts the water flow at the input 30 if the thermostat indicates that the chamber has exceeded its upper temperature boundary.

The heat exchanger 17 of Figure 4 is of a conventional type. Exhaust gases from the internal combustion engine 14 pass into the heat exchanger 17 along a conduit 18 and after passing through the heat exchanger, pass along another conduit 19 to the vehicle exhaust 20. Control valves 21 are provided on either one or other side of the heat exchanger 17 to control the rate of flow. These are controlled by the thermostat.

Figure 5 illustrates a motor coach 13 incorporating a decomposition toilet 23 according to the invention. The coach 13 has a generally conventional form which includes an internal conbustion engine 14 for driving the motor coach and an ablutions area 15 in a lower portion of the coach in which the toilet is positioned. Access to the ablutions area 15 is obtained by steps (not shown) from the passenger accommodation 16 in another portion of the coach 13. In other examples the ablutions area 15 could be located on the same level as the passenger accommodation 16 or on double or upper deck coaches can be situated on the staircase or the upper deck.

The electrical control circuit (Figure 6) comprises a thermostat 29 situated in the lower part of the chamber 2.

A valve 25 is set in a first position (A) to direct heated water into the water jacket 1 if the temperature in the chamber 2 is below 700C. When the temperature exceeds 700C a solenoid is energised by closing a switch 28 to cause the valve to move to position (B) and divert the flow away from the water jacket to allow the chamber to cool. The value reopens at about 500 C.

As previously described where the waste heat is obtained from a liquid such as cooling water this may be pumped directly to the water jacket 10, whereas with other liquids such as engine oil it may be preferable to transfer the heat via the heat exchanger to a circulating supply of water 22 in the water jacket 10 (see Figure 4). In other applications, the heated fluid could comprise heated air from the air-conditioning system of for example an aircraft, or hot water which is subsequently fed to a hot water control member such as a tap of a washing facility.

It should be understood that although in this example all the exhaust gas is passed through the heat exchanger 7 it is possible for only a portion of the exhaust gases to be diverted from the main exhaust system in order to pass through the heat exchanger 17.

A second example of a decomposition toilet is shown in Figure 7. This toilet is based on the BIOLET toilet manufactured by Swedish Ecology AB. The toilet includes a ventilation outlet 30 through which air is drawn by a fan 31, the air being passed over a thermostat 32 to a heating element 33. The heating element comprises a water/air heat exchanger through which heated water is passed, the water having been heated by any of the means mentioned previously in connection with the first example. For example, the water may be waste cooling water or have been heated by a heat exchanger by exhaust gases of the vehicle motor.

The heated air passes through warm air channels 34 into a composting chamber 35. The compost within the chamber 35 is supported on a grate 36 positioned above a humus tray 37.

The rest of the toilet shown in Figure 7 is of conventional construction and will not therefore be described in detail.

Claims

1. A waste treatment system comprising a decomposition chamber comprising a mass receiving chamber, and a heat source, the heat source comprising heat exchanging means for connection to a work performing system which generates heat during performance of its work function, the heat being dissipated by transfer to a fluid; the heated fluid being fed to the heat exchanging means to provide the heat source with heat.

2. A system according to claim 1, wherein the work performing system comprises vehicle drive means.

3. A system according to claim 2, wherein the fluid comprises water from a cooling system of the drive means or lubricant from a lubricating system of the drive means.

4. A system according to claim 2, wherein the fluid comprises exhaust gases from the drive means.

5. A system according to any of claims 1 to 4 wherein the vehicle is a coach, aircraft, ship or train.

6. A system according to any of claims 1 to 4, provided for use in a towed caravan.

7. A system according to any preceding claim, wherein in the decomposition chamber is positioned in an t area separate from the work performing system.

8. A system according to any preceding claim wherein the area is separated from the passenger accommodation of the vehicle by at least one wall.

9. A system according to any of the preceding claims, wherein the heat source heats the decomposition chamber.

10. A system according to any of claims 1 to 8, wherein the heat source heats air supplied to the decompostion chamber.

11. A waste treatment system substantially as hereinbefore described with reference to either of the examples shown in the accompanying drawings.

12. A vehicle incorporating a waste treatment system according to any of the preceding claims.