Human waste processing apparatus

Abstract

NOT VISIBLE DUE TO STATUS OF PATENT

Description

[0001] Human Waste Processing Apparatus

[0002] Field of invention

[0003] The present concept relates to an apparatus to process solid human waste and in particular, although not exclusively, to apparatus and methods to thermally decompose predominantly solid human waste by pyrolysis or torrefaction.

[0004] Background According to the World Health Organisation as reported in June 2019, around 2 billion people do not have basic sanitation facilities such as toilets or latrines. Of these, an estimated 673 million defecate in the open, for example in street gutters, behind bushes or into open bodies of water. Poor sanitation is linked to transmission of diseases such as cholera, diarrhoea, dysentery, hepatitis A, typhoid and polio. In particular, inadequate sanitation, is estimated to cause around 432k diarrhoea deaths annually. Additionally, poor sanitation has been proven to reduce human wellbeing and social and economic development. Additionally, the use of pit latrines is extensive in countries that do not have adequate sewage infrastructures. These latrines typically involve digging a deep pit that provides a waste deposit for small communities. The pit is typically covered by a platform having a suitable hole through which an individual’s waste is deposited. The pit latrine continues in use until it reaches capacity. The waste should then be extracted and disposed of sustainably. However, in many countries across the world, the waste is typically extracted and discharged untreated into a local river or other water course.

[0005] Attempts to address the various problems associated with no or little sewage infrastructure has included with the use of non-flushing or chemical toilets and that may be conveniently supplied and installed in remote and rural communities. It is generally required that such toilets be environmentally friendly, can be easily maintained and require low energy consumption.

[0006] Non-flushing toilets have existed for many years including for example incinerator toilets as described within US 3,020,559 and US 3,230,913. These types of toilet use a coiled electrical heating element to incinerate / bum the faeces with all emitted gases and smoke exhausted via ducts into the surrounding environment. Whilst such devices are effective to kill bacteria and other pathogens within the faeces, they are typically very energy intensive and generate harmful NOX and SOX gases (together with carbon dioxide) that are released into the surrounding environment.

[0007] Chemical toilets collect human excreta in holding tank and use chemicals to minimise odours and in some cases initiate chemical breakdown of the excreta to inhibit the growth of harmful bacteria and pathogens. However, such toilets typically require large holding tanks and significant volumes of disinfectant and deodorising chemicals. Biocides, alcohols and ammonium-based compounds are typically used. However, the collected and chemically treated waste is required to be transported to large-scale sewage processing plants before it can be discharged safely and preferably utilised for applications such as within fertilisers.

[0008] Accordingly, there is a need for improved apparatus and methods for the safe, effective and environmentally sustainable collection and treatment of human waste particularly in deprived regions with poor sanitation facilities and connection to sewage treatment networks.

[0009] Summary of the Invention

[0010] It is an objective of the present invention to provide a solid waste processing system including apparatus and method to process predominantly solid waste including, in particular, human waste (faeces) according to environmentally sustainable, effective and convenient pathways. It is a specific objective to provide a human waste processing system to process waste, including in particular solid human waste, via an energy efficient and environmentally sustainable process.

[0011] The objectives are achieved via apparatus and methods that utilises a pyrolysis process to thermally decompose solid waste and to effectively eliminate pathogens and bacteria within faeces so as to generate a safe and biologically benign product char that may be disposed of conveniently and / or used for one or more applications. Preferably, the present pyrolysis system is configured for torrefaction processing to convert generally solid biomass into a product char via a mild form of pyrolysis involving heating temperatures optionally between 200°C to 350°C. Such a configuration is beneficial to kill pathogens and bacteria within the biomass without releasing harmful product gases such as NOX and SOX pollutants directly into the environment. The present torrefaction thermochemical treatment apparatus and method is conveniently operational at atmospheric pressure and utilises an oxygen depleted environment that is convenient and energy efficient to create and maintain.

[0012] According to a preferred embodiment, the present concept comprises a pyrolysis chamber (within which the torrefaction process is implemented) and a liquid scrubber unit coupled in fluid communication with the pyrolysis chamber to receive gases and / or moisture vapour. Additionally, the present concept may further comprise a slurry return conduit to provide recirculation of a slurry form of waste through the pyrolysis chamber and a solid extraction conduit having a second heater to further heat the predominantly solid form of waste for subsequent disposal as char. Additionally, the present concept may further comprise at least one gas / moisture vapour return conduit. Such a conduit may be provided to extend between i) a region approximately positioned at or towards an outlet of at least one heating chamber and ii) a region approximately positioned at or towards an inlet of at least one heating chamber. Optionally, at least one gas / moisture vapour return conduit may be provided to extend between i) a region approximately positioned at or towards an outlet of at least one heating chamber and ii) a gas scrubber unit containing a scrubbing liquid. Such arrangements are advantageous to avoid emission of pyrolysis product gases and vapour directly into the surrounding environment. By exhausting such gases and moisture vapour directly into the body of a scrubber liquid, the gases are captured and may be subsequently reacted and / or otherwise chemically treated via subsequent downstream liquid processing apparatus and procedures. Additionally, by recirculating the slurry form of the waste back through at least one heating chamber, an energy efficient process is provided via the controlled stepwise heating of the waste and the collection of waste vapour which may then be processed via the scrubber unit. Additionally, the final stage heating of the predominantly solid form of the waste contributes to the energy efficiency of the system whilst further collecting moisture vapour and harmful gas products as the waste is converted to a compact form of char.

[0013] According to one aspect of the present concept there is provided a human waste processing device comprising: a heating vessel having an internal heating chamber, a waste inlet, a waste outlet and a first heater positioned in a gravity assisted waste processing direction between the inlet and the outlet; an enclosure provided at or connected to an outlet region of the chamber to receive partially dried waste; a slurry return conduit having an intake region provided at the enclosure and an outlet region provided at the heating chamber to enable recirculation of a slurry form of the waste through the heating chamber; a flow actuator to drive a flow of the slurry form of the waste from the intake region to the outlet region of the slurry return conduit; and a solid extraction conduit having an intake region provided at the enclosure, an outlet region to discharge solid waste and a second heater positioned in a waste processing direction between the intake region and outlet region of the second heating vessel. Optionally, the first heating vessel is elongate and is configured for positioning in a generally upstanding or vertical orientation such that the waste is configured to transfer at least partially under gravity from the inlet to the outlet of the vessel. The first heating vessel may comprise a lengthwise section that is funnel shaped having a reducing radius in a downward direction from the first upper end to a second lower end. Preferably, the heater is provided at or towards the second lower end. Such an arrangement facilitates the downward compacting of waste and the efficient heating of the waste by the heating elements.

[0014] Reference to an enclosure herein encompasses a housing or vessel having an internal chamber or cavity to receive an inflow of at least partially dried waste from the outlet of at least one heating vessel. Such an enclosure may be suited to facilitate separation of solid and liquid waste and may be referred to as a separation enclosure, housing or chamber.

[0015] Preferably, the second heating vessel is elongate having a main length orientated inclined or extending upwardly from the separation enclosure. Preferably, the second heating vessel is tubular and comprises a uniform radius along its length. This facilitates upward travel of the by a waste transporter located within the second heating vessel.

[0016] Preferably, the first heating vessel further comprises a waste actuator positioned within the heating chamber to compress and / or facilitate movement of the waste from the inlet to the outlet region. Optionally, the waste actuator comprises at least one blade projecting radially outward from a shaft and a drive actuator to rotate the shaft and the blade about a longitudinal axis of the shaft. Optionally, the shaft and / or the blade extend between the inlet and outlet region and / or extend over a majority of a length of the heating chamber. Optionally, at least a portion of the heating chamber is cylindrical, conical and / or funnel shaped.

[0017] Preferably, the first heating vessel and / or the second heating vessel is an air sealed vessel to prevent or impede an intake of air into the respective heating chamber such that the first heating vessel and / or the second heating vessel is configured for pyrolysis or torrefaction processing of the human waste. Optionally, the device may comprise a scrubber unit having a tank to contain a scrubber liquid and provided with a gas outlet and a gas / moisture vapour inlet coupled to a gas / moisture vapour outlet provided at the first heating vessel and / or the second heating vessel. Preferably, the tank comprises a scrubber liquid and an aperture of the gas / moisture vapour inlet from which a gas / moisture vapour is configured to enter is positioned submerged within the scrubber liquid and an aperture of the gas outlet through which a gas is configured to vent from the tank is positioned above and clear of the scrubber liquid. Optionally, the tank may comprise a liquid outlet aperture to allow a liquid to flow from the tank, the liquid outlet aperture positioned intermediate the aperture of the gas / moisture vapour inlet and the aperture of the gas outlet. Optionally, the tank may be elongate and configured to collect and retain a pre-determined volume of a scrubber liquid within a lower region of the tank, the liquid outlet aperture positioned between respective lengthwise ends of the tank to provide an overflow weir to maintain the pre-determined volume of the scrubber liquid within the tank. Optionally, the gas / moisture vapour inlet of the scrubber unit may be coupled directly or indirectly to a gas / moisture vapour outlet of the first heating vessel and / or the second heating vessel. Optionally, wherein the gas / moisture vapour inlet of the scrubber unit is coupled to the at least one gas / moisture vapour outlet exclusively via at least one one-way valve.

[0018] Optionally, the first heater and / or the second heater comprise any one or a combination of at least one electrical resistance heating element; a Peltier heater; at least one heating collar positioned circumferentially around a heating zone at the respective heating chamber and / or the solid extraction conduit, the zone located between the respective inlet or intake and outlet regions.

[0019] Optionally, the first heating vessel may comprise a wiper blade positioned at the inlet of the heating vessel to facilitate transfer of waste into the heating chamber.

[0020] Optionally, the slurry return conduit may comprise a liquid entry port to enable a liquid to be introduced into the slurry return conduit and to flow into the heating chamber of the first heating vessel. Optionally, the device may comprise a mesh or screen provided at or proximate to the liquid entry port of the slurry return conduit. Optionally, the flow actuator is a pump provided in a fluid flow direction at the intake or outlet region or between the intake and the regions of the slurry return conduit. The pump may be any type of liquid flow pump associated with liquid transport from one location to another such as positive-displacement, centrifugal and axial-flow pumps.

[0021] Optionally, the second heating vessel comprises an elongate screw conveyor rotatably mounted within the heating chamber having at least one helical blade projecting radially outward from an elongate shaft. Optionally, a first lengthwise region of the blade axially closest to the intake region comprises a first material having a first hardness and a second lengthwise region of the blade axially closest to the outlet region of the second heating vessel comprises a second hardness being greater than the first hardness.

[0022] Optionally, the apparatus may comprise a waste intake conduit having a first end connected to or provided at the first heating vessel and a second end connected to or provided at a source of human waste. Optionally, the waste intake conduit comprises a screw conveyor having at least one helical blade projecting radially outward from a central shaft. Optionally, a first lengthwise region of the blade axially closest to the intake region comprises a first material having a first hardness and a second lengthwise region of the blade axially closest to the outlet region of the waste intake conduit comprises a second hardness being greater than the first hardness. Optionally a second lengthwise end region of the screw conveyor extends into the internal heating chamber of first heating vessel. This is advantageous to deliver and / or dispense solid-liquid waste into the chamber interior and avoid / inhibit blockage of an inlet of the heating chamber.

[0023] Optionally, the waste intake conduit may comprise a tube or hose and the apparatus further comprises a pump to provide a suction force at the waste intake conduit to transfer waste through the waste intake conduit to the first heating vessel. Optionally, the present concept may comprise a plurality of sensors to monitor various aspects of the system. Optionally such sensors may comprise at least one temperature sensor, pressure sensor, flow sensor, pH sensor, moisture sensor, mass / weight sensor etc. Such sensors may be located at a variety of different locations within the system.

[0024] According to a further aspect of the present concept there is provided a method of processing human waste comprising: heating waste at a first heating vessel having an internal heating chamber, a waste inlet, a waste outlet and a first heater positioned in a gravity assisted waste processing direction between the inlet and the outlet; receiving partially dried waste at a separation enclosure provided at or connected to an outlet region of the chamber; recirculating a slurry form of the waste through the heating chamber via a slurry return conduit having an intake region provided at the separation enclosure and an outlet region provided at the heating chamber; driving a flow of the slurry form of the waste through the slurry return conduit; and extracting a solid form of the waste by heating the waste within a second heating vessel having an internal heating chamber, an intake region provided at the separation enclosure, an outlet region to discharge solid waste and a second heater positioned in a waste processing direction between the intake and outlet regions.

[0025] According to a further aspect of the present concept there is provided a method of processing human waste comprising: heating waste at an elongate first heating vessel having an internal heating chamber, a waste inlet, a waste outlet and a first heater positioned between the inlet and the outlet, the first heating vessel positioned in a generally upstanding or vertical orientation such that the waste is configured to transfer at least partially under gravity from the inlet to the outlet of the vessel; receiving partially dried waste at an enclosure provided at or connected to an outlet region of the chamber; and extracting a solid form of the waste by heating the waste within a second heating vessel having an internal heating chamber, an intake region provided at the enclosure, an outlet region to discharge solid waste and a second heater positioned in a waste processing direction between the intake and outlet regions. Optionally, the method may further comprise: recirculating a slurry form of the waste through the heating chamber of the first heating vessel via a slurry return conduit having an intake region provided at the enclosure and an outlet region provided at the heating chamber of the first heating vessel; and driving a flow of the slurry form of the waste through the slurry return conduit.

[0026] According to a further aspect of the present concept there is provided human waste processing device comprising: a first heating vessel having an internal heating chamber, a waste inlet, a waste outlet and a first heater positioned in a waste processing direction between the inlet and the outlet; a separation enclosure provided at or connected to an outlet region of the chamber to receive partially dried waste; a slurry return conduit having an intake region provided at the separation enclosure and an outlet region provided at the heating chamber to enable recirculation of a slurry form of the waste through the heating chamber; and a second heating vessel having an intake region provided at the separation enclosure, an outlet region to discharge solid waste and a second heater positioned in a waste processing direction between the intake region and outlet region of the solid extraction conduit.

[0027] According to one aspect of the present concept there is provided a human waste processing device comprising: a heating vessel having an internal heating chamber, a waste inlet, a waste outlet and a first heater positioned in a gravity assisted waste processing direction between the inlet and the outlet; a separation enclosure provided at or connected to an outlet region of the chamber to receive partially dried waste; a slurry return conduit having an intake region provided at the separation enclosure and an outlet region provided at the heating chamber to enable recirculation of a slurry form of the waste through the heating chamber; a flow actuator to drive a flow of the slurry form of the waste from the intake region to the outlet region of the slurry return conduit; and a solid extraction conduit having an intake region provided at the separation enclosure, an outlet region to discharge solid waste and a second heater positioned in a waste processing direction between the intake region and outlet region of the solid extraction conduit. According to one aspect of the present concept there is provided a human waste processing device comprising: a first heating vessel having an internal heating chamber, a waste inlet, a waste outlet and a first heater positioned in a gravity assisted waste processing direction between the inlet and the outlet, wherein the first heating vessel is elongate and is configured for positioning in a generally upstanding or vertical orientation such that the waste is configured to transfer at least partially under gravity from the inlet to the outlet of the vessel; an enclosure provided at or connected to an outlet region of the chamber to receive partially dried waste; and a second heating vessel having an internal heating chamber, an intake region provided at the enclosure, an outlet region to discharge solid waste and a second heater positioned in a waste processing direction between the intake region and outlet region of the second heating vessel.

[0028] Optionally, the device may comprise a slurry return conduit having an intake region provided at the enclosure and an outlet region provided at the heating chamber to enable recirculation of a slurry form of the waste through the heating chamber; and a flow actuator to drive a flow of the slurry form of the waste from the intake region to the outlet region of the slurry return conduit.

[0029] Brief description of drawings

[0030] A specific implementation of the present invention will now be described, by way of example only, and with reference to the accompanying drawings in which:

[0031] Figure l is a perspective view of apparatus to process human waste having a first heating vessel, an emissions scrubber unit / tank, a heating chamber recirculation unit and a second heating vessel according to one aspect of the present concept;

[0032] Figure 2 is a partial cross-sectional view of the apparatus of figure 1;

[0033] Figure 3 is a further partial cross-sectional view of the apparatus of figure 1; Figure 4 is a partial cross-sectional view of a heating vessel and / or chamber part of the apparatus of figure 1 ;

[0034] Figure 5 is a schematic illustration of a pit latrine provided with the human waste processing apparatus according to one embodiment of the present concept;

[0035] Figure 6 is a perspective view of an integrated modular toilet assembly configured for processing human waste according to a specific implementation.

[0036] Detailed description of preferred embodiment of the invention

[0037] Referring to figures 1 to 4, human waste processing apparatus 70 comprises as main components, a pyrolysis / torrefaction unit 16 (first heating vessel 82) coupled to a solid and liquid transporter 14; a predominantly liquid waste recirculation assembly 61; an emission scrubber module 10 having an emission scrubber 15; and a second stage heating unit 41 (second heating vessel). Apparatus 70 is configured specifically for the processing and treatment of predominantly solid waste (faeces / faecal matter). Gas / moisture vapour conduits 45a and 45b provide fluid communication between the emission scrubber 15 and the pyrolysis / torrefaction unit 16 (first heating vessel 82) and the second stage heating unit 41.

[0038] The human waste processing apparatus 70 is configured specifically for the processing and treatment of predominantly solid waste (faeces / faecal matter). Emission scrubber 15 comprises a liquid containment tank 15a. Tank 15a and chamber 18 are elongate and comprise a first upper end 34a and a second lower end 34b. Lower end 34b is mounted to support plate that also mounts the pyrolysis unit 16 such that both units 16, 15 are mounted side-by-side. The emission scrubber 15 comprises a gas / moisture vapour inlet defined generally by reference 21. Inlet 21 comprises an elongate inlet tube 33 that extends from the first upper end 34a towards second lower end 34b. A lower terminal end of tube 33 comprises an aerator 24 having a series of apertures 24a. Aerator 24 is accordingly positioned in a lower half of chamber 18 closer towards second lower end 34b relative to first upper end 34a. Liquid outlet 23 is positioned in a lengthwise direction between ends 34, 35 in an upper half of tank 15a and chamber 18. Emission scrubber 15 also comprises a gas / moisture vapour outlet indicated generally by reference 22 located at the first upper end 34a. Accordingly, the gas / moisture vapour inlet 21, and in particular an inlet aperture 24a of inlet 21, is positioned towards or in close proximity to the second lower end 35 whilst the gas / moisture vapour outlet 22 is positioned at or in close proximity to first upper end 34a. Liquid outlet 23 is positioned in a lengthwise direction intermediate inlet aperture 24a and gas outlet 22. Emission scrubber 15 is configured to collect and contain a scrubber liquid 40 occupying a lower region of the tank 15a. Accordingly, aerator 24 and gas inlet aperture 24a is configured to be submerged within the scrubber liquid 40.

[0039] Pyrolysis unit 16 comprises a vessel 82 defining an internal chamber 17. An upper region of chamber 17 is radially enlarged relative to a lower region lower region of chamber 17 that comprises a radially inward curving / tapered internal guide surface 25. At a region below guide surface 25, chamber 17 comprises a radially reduced cylindrical section that in turn defines a lower heating zone 31 of the pyrolysis unit 16. Zone 31 is surrounded by a heating jacket 43. According to the specific implementation, this first heater (heating jacket) 43 is divided into a first heating collar 43b and a second heating collar 43a with both collars 43a, 43b axially and circumferentially encapsulating zone 31. Zone 31 is positioned immediately above and in internal communication with a separation enclosure indicated generally be reference 39.

[0040] Pyrolysis unit 16 further comprises a solid matter inlet port 19 and a gas / moisture vapour outlet 20. Solid matter inlet 19, comprises an inlet aperture 19a from which solid matter is configured to be deposited within chamber 17. As illustrated in figures 1 to 4, solid waste inlet 19 is positioned towards the upper end region 16a of vessel 82 such that solid matter falls downwardly under gravity towards and in contact with tapered guide surface 25. Gas / moisture vapour outlet 20 also comprises an outlet aperture positioned at or near the upper inlet end 16a of vessel 82.

[0041] Pyrolysis unit 16 also comprises an internal waste actuator indicated generally by reference 26. Actuator 26 is generally elongate and comprises a first end 26a that projects upwardly from vessel 82 and is mounted within an electric motor indicated generally by reference 27a. An opposite second end of actuator 26 is radially enlarged relative to the actuator main length to define an actuating drum 30, rotatably mounted within zone 31. An opposite second end of actuator 26 is radially enlarged relative to the actuator main length to define the actuating drum 30, rotatably mounted within zone 31. Drum 30 comprises a partially domed or conical, radially tapering outer surface so as be radially enlarged at its lower end relative to its upper end. As such drum 30 tapers radially inward from the main length of actuator 26 and in opposite tapered relationship relative to the radially inward tapered surface 25 extending from the upper section of vessel 82. Actuator 26 is hollow to comprise an internal bore 28 extending over at least half of its lower length from a lower end into an upper section. At least one vent port (not shown) provides fluid communication with the internal chamber 17 and the internal bore 28 for the passage of gas.

[0042] According to the specific implementation, heater (heating jacket) 43 is divided into the first collar 43b and the second collar 43a with both collars 43a, 43b axially and circumferentially encapsulating zone 31. Zone 31 is positioned immediately above and in internal communication with the separation enclosure 39. Separation enclosure 39 defines an internal chamber having an inlet end coupled to the outlet 16b of heating chamber 17 and an outlet end coupled in internal communication with the second stage heating unit 41 via an inlet 62 of a second stage heating unit 41.

[0043] Recirculation assembly 61 comprises a first conduit 56 having a first end 56a coupled to the inlet region 16a of chamber 17 and a second end 56b coupled to a pump 57. Assembly 61 further comprises a second conduit 58 having a first end coupled to pump 57 and a second end 58a coupled in internal communication with a lower or base region of separation enclosure 39 and / or first longitudinal end region 44a of second stage heating unit 41. Accordingly, recirculation assembly 61 is configured to transfer predominantly liquid waste within the separation enclosure 39 via the conduits 58 and 56 to the inlet region 16a of vessel 82.

[0044] At least one helical rib 49 projects radially outward from an external facing surface 48 of drum 30, with rib 49 extending helically about a longitudinal rotational axis 50 of actuator 26. Vessel 82 at the heating zone 31 comprises a corresponding internal facing surface 47 so as to create an annular gap region indicated generally by reference 46 between the respective surfaces 48 and 47. The at least one helical rib 49 projects radially into the gap region 46 from drum 30. An annular aperture 32a is defined between a lengthwise lower terminal end of drum 30 and the corresponding lengthwise lower terminal end of zone 31. Accordingly, partially dried solid waste is transferred from gap region 31 via annular aperture 32a into the separation enclosure 39. The downward transport of waste within chamber 17 is achieved via gravity with assistance provided by the helical blade 49 that, being rotated by drive motor 27a, pushes solid waste downwardly through the heating zone 31.

[0045] The liquid waste settles to the lower region of separation enclosure 39 and into contact with the recirculation conduit end 58a. Via pump 57, predominantly liquid waste is recirculated via conduits 58 and 56 into inlet region 16a of vessel 82. Predominantly solid waste is separated at separation enclosure 39 by the action of the second stage heating unit 41. In particular, unit 41 comprises a generally elongate tube-like vessel 72 having a first end 44a and second end 44b. Tubular vessel 72 comprises a longitudinal axis 63 that is inclined upwardly at an angle 9 relative to the generally vertical axis 50 extending longitudinally through pyrolysis unit 16 and in particular chamber 17. Accordingly, waste is processed and heated via a first gravity assisted downward vertical flow pathway (through vessel 82) and then to travel at an inclined angle 9 upwardly through the second vessel 72 (stage heating unit 41) from first end 44a to second end 44b. Transfer of the solid waste from the first end 44a of tubular vessel 72 to second end 44b is achieved via a screw conveyor formed by an elongate rod 53 having a helical fin 54 extending lengthwise between ends 44a, 44b. A drive motor 27b provided at a drive head 69 (located at second end 44b) provides rotation of rod 53 and fin 54 about axis 63.

[0046] Second stage heating unit 41 comprises a heating collar 52 extending circumferentially around an exterior surface of vessel 72. According to the specific implementation, heating collar 43 and / or 52 comprises Peltier heating elements. However, according to further embodiments, heating collars 43 and / or 52 may comprise resistance wire heating elements and the like. Accordingly, as predominantly solid waste is transported from first end 44a to second end 44b, it is heating during the second / final stage heating via heating collar 52. Any residual liquid waste flows downward under gravity due to the inclined angle 0 of the unit 41, with this predominantly liquid waste being recirculated into the pyrolysis unit 16 via recirculation assembly 61. An outlet 32 is provided at second end 44b of tubular vessel 72 and is provided in internal communication with a char collection trap 38. Accordingly, the final stage solid waste is deposited from the second stage heating unit 41 into the char collection trap 38 via an aperture 84. A suitable scrapper blade (not shown) may be provided at or towards second end 44b to encourage the solid waste to fall under gravity into collection trap 38 via aperture 84. Trap 38 may comprise a removable tray for removing char deposited from unit 41. Vessel 72 / unit 41 may be configured for pyrolysis / torrefaction heating of the waste in the same manner as pyrolysis unit 16 and accordingly may comprise seals and valves etc to prevent ingress of air into the vessel 72 and / or trap 38.

[0047] Waste is transported to the pyrolysis unit 16 from a waste reservoir or other source location via transporter 14. The solid matter is received at the pyrolysis unit 16 via inlet 19a. Transporter 14 comprises a screw conveyor formed from an elongate shaft 29 having a first end lower end 37 and a second upper end 42. A helical blade 36 projects radially from shaft 29 to provide a guide fin to transport the waste upwardly through elongate tube 74 through which the screw conveyor extends between ends 74a and 74b of elongate tube 74. In particular, a tube lower end 74a is positionable in communication with a waste reservoir or other source of waste whilst a tube second 74b is coupled in internal communication with inlet 19a of pyrolysis unit 16. Accordingly, waste is capable of being transported upwardly through tube 74 as the screw conveyor is rotated about its longitudinal axis via a drive motor 27c. Waste is then dislodged from accumulation around blade 36 at blade terminal end 46 via a scrapper 51 located within the chamber 17. Waste is then deposited to fall downwardly into chamber 17 and into contact with helical rib / blade 49 where it is compressed and forced downwardly with gravity into the heating zone 31.

[0048] To facilitate capture and transport of the waste initially via transporter 14, the inventors have identified that blade 36 is preferably divided into a plurality of sections, with each section comprising a different material and / or material composition. In particular, a first section 14a of blade 36 comprises a first material type being of softer, more deformable and / or more hydrophilic relative to a second section 14b that may comprise a second material or second material composition that may differ from the first section 14a via any one of hardness, flexibility, hydrophobicity. Optionally, one or both sections 14a, 14b may comprise a surface coating at blade 36. In particular, first section 14a is adapted via the blade material, blade material composition and / or surface coating to facilitate collection and transport of the of human waste that may comprise a 50:50 mixture of liquid and solid waste (urine and faeces). As the waste is transported upwardly, the predominantly liquid form of the waste loses contact with the helical blade 36 and flows downwardly over the inner surface of tube 74. Accordingly, predominantly solid waste is delivered by the second upper section 14b into the pyrolysis chamber 17. It is however appreciated that such waste still includes a substantial amount of liquid (urine).

[0049] Predominant solid matter 42 is then deposited within chamber 17 to fall under gravity and to collect at the generally funnel shaped guide surface 25. Unit 16 may comprise suitable electronic sensors (for example motion, moisture, pressure, contact, temperature sensors etc) to provide / facilitate actuation of motor 27a and a corresponding rotation of actuator 26 within chamber 17 about axis 50. Accordingly, drum 30 is configured to rotate within zone 31. Solid matter 42 via the conical guide surface 25 is encouraged to fall under gravity into the annular region 46 between drum 30 and jacket heater 43. During this initial stage, at least one of the heating collars 43a, 43b is actuated to provide modest heating of the solid matter 42 within chamber 17 and in particular any solid matter within gap region 46. Alternatively, at least one of the heating collars 43a, 43b may be actuated so as to providing heating of gap region 46 and internal chamber 17 prior to rotational drive of actuator 26.

[0050] This initial drying phase is preferably operated at around 70°C and is configured to remove water and oxygen within waste. Importantly, restricting this drying process to not more than 70°C is advantageous to avoid release of nitrogen and sulphur compounds from the solid matter 42. This initial drying phase may be undertaken for 30 minutes to 2 hours whilst actuator 26 is rotated. Oxygen and water vapour are driven from chamber 17 through the gas outlet 20, conduit 45a and tube 33 to be exhausted into the scrubber liquid 40 via aperture 24a. In a preferred implementation, scrubber 15 may be "primed’ with a scrubber liquid for example by introducing a predefined volume of liquid into tank 15a. The initial drying phase of the present concept is further advantageous to replenish the scrubber liquid 40 within tank 15a and in particular to dilute the scrubber liquid 40 with freshwater condensate. This pre-pyrolysis heating phase (at the modest temperature below that of the subsequent pyrolysis heating phase) is beneficial to firstly maintain a predefined volume of scrubber liquid 40 within tank 15a and also to inhibit the scrubber liquid 40 becoming too acidic due to elevated concentrations of nitrogen and sulphur containing compounds. Importantly, as inlet aperture 24a of the scrubber 15 is submerged within scrubber liquid 40 oxygen, water vapour and any product gases driven and released from solid matter 42 during this drying phase (and the subsequent torrefaction phase) are exhausted directly into the scrubber liquid 40 where they are at least partially solvated / dissolved. As indicated, the volume of scrubber liquid 40 is maintained at a predetermined level via the presence and position of liquid outlet 23 positioned intermediate inlet aperture 24a and the gas / moisture vapour outlet 22.

[0051] Pyrolysis within chamber 17 is achieved via appropriate fluid seals and valves at the various inlet and outlet ports. In particular, solid waste inlet port 19 comprises a perimeter region (not shown) that is profiled so as to sit in close fitting contact with aperture 19a and provide a fluid seal. A one-way valve (not shown) is provided within conduit 45a to prevent the return-flow of gas, in particular oxygen and water vapour, from the scrubber 15 into chamber 17. Appropriate seals are also provided around actuator 26 at first end 26a of mounting at the external drive motor 27a.

[0052] As the initial drying phase approaches completion, the predetermined volume of scrubber liquid 40 within tank 15a is achieved with any excess scrubber liquid allowed to drain via an liquid outlet. This is effective to maintain a predetermined pH and to minimise the accumulation of dissolved nitrogen and sulphur compounds within scrubber liquid 40. Scrubber 15 also comprises a liquid drain outlet and conduit for connection to an output tank or liquid treatment module (not shown). This is useful to empty tank 15a for maintenance purposes or to completely refresh the scrubber liquid 40. Once substantially all the oxygen and moisture is expelled from the solid waste 42, the system is then adapted to the second pyrolysis phase. Actuator 26 is rotated to facilitate downward movement of the dried solid waste 42 into the heating zone 31. The rotational speed of actuator 26 is controlled such that when combined with gravity, the solid waste 42 is transported at a predetermined speed in a downward direction through the heating zone 31 as the heating collars 43a, 43b are actuated. The present system is configured specifically for the controlled heating of the solid matter 42 to inhibit / minimise the generation of harmful Syngas gas emissions including NOX, SOX, CO and NH3. The minimised emission of these gases is achieved by a combination of the exhausting of all product gases into the scrubber liquid 40 and a configuration of the heating zone 31 and the method / parameters by which the solid matter 42 is heated within chamber 17 and in particular zone 31 and also via the recirculation of the waste (via unit 61) through the heating unit 16. Preferably, the present system is configured for the recirculated processing by torrefaction of the waste being a mild form of pyrolysis. Preferably, the heating collars 43a, 43b are actuated to achieve a heating temperature of around 300°C and optionally less than 250°C and preferably a heating temperature of around 200°C being sufficient to destroy bacteria and viruses within solid matter 42. As the solid matter falls under gravity into the heating zone 31 it is transported downwardly to the annular aperture 32a by helical rib 49. Gases generated from the heating of the biomass 42 are also pushed downwardly through the annular heating zone 31. These gases flow via annular aperture 32a into the hollow open end and interior of actuator drum 30 to then flow upwardly through bore 28 where they are vented into chamber 17 via vents (not shown). Providing this exhaust gas pathway from the annular heating zone 31 internally through the drum 30 and actuator 26 prevents blockage of the downward movement of the biomass 42 within the annular heating zone 31 that may otherwise occur due to pressure build-up at this region.

[0053] The gases generated from the torrefaction of the biomass 42 are exhausted directly into the scrubber liquid 40 via aerator apertures 24a that is submerged within liquid 40. Any NOX, SOX, CO, NH3 generated from the torrefaction are at least partially absorbed by scrubber liquid 40. Optionally, an alkaline mesh or brick insert may be mounted within tank 15a to counter the reducing pH levels resultant from the absorbed gases. Additionally, a similar filter insert may be provided at the upper region of chamber 18 internally or externally relative to gas / moisture vapour outlet 22 so as to provide a scrubbing of any gases vented from chamber 18. Optionally, the scrubber 15 may comprise a carbon or activated carbon / charcoal scrubber cartridge.

[0054] The biomass 42 having been heated continuously whilst being transported axially downward through the annular heating zone 31 is then deposited into the separation enclosure 39. As indicated, predominantly solid waste is separated from predominantly liquid waste within the separation enclosure 39, with the predominantly liquid waste being recirculated into the pyrolysis chamber 17 via recirculation assembly 61. The predominantly solid waste is transported onwardly through the second stage heating unit 41 where it is heated further by heating collar 52 to expel any remaining liquid waste to provide the resulting char collectable within trap 38. The predominantly liquid waste is recirculated sequentially through the pyrolysis chamber 17 and is heated in sequence to raise the temperature by approximately 10° each time the waste passes through the heating zone 31 (to be heated by heating elements 43a, 43b). Once the phase of the waste changes from predominantly liquid to predominantly solid, the waste is then "picked-up ’ by the screw conveyor (53, 54) of the second stage heating unit 41. Accordingly, the present apparatus provides an internally recirculating liquid-solid separator and waste treatment apparatus having end products in the form of completely dry char and harmless gas emissions. The char may then be removed from trap chamber 38a via a removable tray and door (not shown) provided at trap 38. The gas emissions from scrubber unit 15 may be captured or otherwise processed by downstream apparatus as required. A vapour conduit 45b extends from head unit 60 to the gas / moisture vapour conduit 45a extending between chamber 17 and scrubber unit 15. Accordingly, gas / vapour resultant from the second stage drying of the waste by second heating unit 41 (specifically heater 52 mounted within vessel 72) is transferred to the scrubber unit 15 via conduits 45b, 45a via scrubber inlet 21. As will be appreciated, the helical fin 54 may comprise the same multi sectional configuration (having different material types, compositions, coatings etc) as described referring to blade 36 of the transporter 14. The drying and pyrolysis (torrefaction) sequential stages may then be repeated to replenish and dilute the scrubber liquid 40 (by condensation of water vapour within chamber 17) and to thermally decompose the biomass 42. The present system is advantageous to regenerate and replenish the scrubber liquid 40 via the initial drying phase whilst also destroying bacteria and viruses within the biomass 42 during the subsequent low temperature pyrolysis. The present system via maximum heating temperatures of the order of around 200°C is energy efficient and adapted to control and minimises harmful gas emissions such as NOX, SOX, CO, NH3.

[0055] Unit 16 further comprises a liquid / waste liquid inlet port 83 provided at upper region 16a of vessel 82. Port 83 enables introduction of a liquid into chamber 17 and also into transporter 14 and in particular tube 74. Such an arrangement is advantageous to allow internal flushing / cleaning of chamber 17 and tube 74 to as to remove waste that may be adhered to the inner surfaces of chamber 17 and tube 14 that may otherwise inhibit the intended transport of waste upward and along tube 74 and downwardly within chamber 17. Port 83 may be coupled in fluidic communication with a source of water or wastewater forming part of a waste liquid network or toilet module 11 described referring to figure 6 herein.

[0056] Referring to figure 5, the waste processing apparatus 70 may be utilised for the processing of human waste at a pit latrine. Typically, a pit latrine comprises hole or pit 66 dug into the ground. An enclosure or platform 80 extends over and open end of the pit 66 and may comprise a bowl or toilet-like receptacle 68 into which an individual deposits human waste. Receptacle 68 may be positioned within a housing 67 located at ground level. Solid processing apparatus 70 is supported on a carriage or crate 71 and housed within a storage location 69 adjacent housing 67. The waste transporter 14 according to the pit latrine embodiment comprises an elongate flexible tube having a first end 37 submerged within human waste deposit 64 at the lowest region of pit 66. The waste 64 may then be transported upwardly 64a through transporter 14 into the pyrolysis unit 16 as described referring to figures 1 to 4. According to further implementations, transporter 14 may comprise a suction conduit provided with a suction pump or other pump mechanism (not shown) to drive uptake of the waste 64 and transfer 64a into the pyrolysis unit 16. The waste 64 may then be processed according to the components and functionality described referring to figures 1 to 4 to output char that may then be collected within trap 38 whilst the byproduct gases may be collected, processed and / or emitted via scrubber unit 15.

[0057] Figure 6 illustrates a further utilisation of the present waste processing apparatus 70 in the form of a toilet module 11. Module 11 may be installed within a building, vehicle, train, aircraft etc. Module 11 comprises a frame I la supporting a variety of modular components including a front-end toilet 12; the pyrolysis unit 16; solid-liquid transporter 14; scrubber module 10, recirculation assembly 61 and the second stage heating unit 41, as described referring to figures 1 to 4. Modular 11 further comprises a liquid treatment module illustrated generally by reference 13 comprising a plurality of tanks 13a and at least one filtration module 13b configured to process predominantly liquid waste as described in WO 2022 / 214576 Al that is incorporated herein by reference. Accordingly, toilet module 11 is configured to process both liquid waste and solid waste via the combined processing of the liquid treatment module 13 and the predominantly solid waste processing apparatus 70 including components / units 14, 16, 10, 41, 61.

[0058] According to further embodiments, the processing apparatus 70 may comprise all features and function as described referring to the embodiment of figures 1 to 4 but without a recirculation assembly 61. In such an embodiment, a slurry form of the waste output from internal chamber 17 may be transferred to the second stage heating unit 41 (second heating vessel). The apparatus 70 is configured specifically for the processing and treatment of predominantly solid waste (faeces / faecal matter). Gas / moisture vapour conduits 45a and 45b provide fluid communication between the emission scrubber 15 and the pyrolysis / torrefaction unit 16 (first heating vessel 82) and the second stage heating unit 41 such that any gas and / or vapour generated by the heating process is not emitted to the environment. Vapour conduits 45a and 45b are also connected to the inlet region of the pyrolysis / torrefaction unit 16 to recirculate the gas and / or vapour. Valves may be included at conduits 45a and 45b to direct the gas and / or vapour to the scrubber unit 15 and / or the pyrolysis / torrefaction unit 16.

Claims

Claims1. Human waste processing device comprising: a first heating vessel having an internal heating chamber, a waste inlet, a waste outlet and a first heater positioned in a gravity assisted waste processing direction between the inlet and the outlet, wherein the first heating vessel is elongate and is configured for positioning in a generally upstanding or vertical orientation such that the waste is configured to transfer at least partially under gravity from the inlet to the outlet of the vessel; an enclosure provided at or connected to an outlet region of the chamber to receive partially dried waste; and a second heating vessel having an internal heating chamber, an intake region provided at the enclosure, an outlet region to discharge solid waste and a second heater positioned in a waste processing direction between the intake region and outlet region of the second heating vessel.

2. The device as claimed in claim 1 further comprising: a slurry return conduit having an intake region provided at the enclosure and an outlet region provided at the heating chamber to enable recirculation of a slurry form of the waste through the heating chamber; and a flow actuator to drive a flow of the slurry form of the waste from the intake region to the outlet region of the slurry return conduit.

3. The device as claimed in claim 1 or 2 wherein the second heating vessel is elongate having a main length orientated inclined or extending upwardly from the enclosure.

4. The device as claimed in any preceding claim wherein the first heating vessel further comprises a waste actuator positioned within the heating chamber to compress and / or facilitate movement of the waste from the inlet to the outlet region.

5. The device as claimed in claim 4 wherein the waste actuator comprises at least one blade projecting radially outward from a shaft and a drive actuator to rotate the shaft and the blade about a longitudinal axis of the shaft.

6. The device as claimed in claim 5 wherein the shaft and / or the blade extend between the inlet and outlet region and / or extend over a majority of a length of the heating chamber.

7. The device as claimed in any one of claims 4 to 6 wherein at least a portion of the heating chamber is cylindrical, conical and / or funnel shaped.

8. The device as claimed in any preceding claim wherein the first heating vessel and / or the second heating vessel is an air sealed vessel to prevent or impede an intake of air into the respective heating chamber such that the first heating vessel and / or the second heating vessel is configured for pyrolysis or torrefaction processing of the human waste.

9. The device as claimed in any preceding claim further comprising a scrubber unit having a tank to contain a scrubber liquid and provided with a gas outlet and a gas / moisture vapour inlet coupled to a gas / moisture vapour outlet provided at the first heating vessel and / or the second heating vessel.

10. The device as claimed in claim 9 wherein the tank comprises a scrubber liquid and an aperture of the gas / moisture vapour inlet from which a gas / moisture vapour is configured to enter is positioned submerged within the scrubber liquid and an aperture of the gas outlet through which a gas is configured to vent from the tank is positioned above and clear of the scrubber liquid.

11. The device as claimed in claim 10 wherein the tank of the scrubber unit comprises a liquid outlet aperture to allow a liquid to flow from the tank, the liquid outlet aperture positioned intermediate the aperture of the gas / moisture vapour inlet and the aperture of the gas outlet.

12. The device as claimed in claim 11 wherein the tank is elongate and configured to collect and retain a pre-determined volume of a scrubber liquid within a lower region of the tank, the liquid outlet aperture positioned between respective lengthwise ends of the tank to provide an overflow weir to maintain the pre-determined volume of the scrubber liquid within the tank.

13. The device as claimed in any one of claims 9 to 12 wherein the gas / moisture vapour inlet of the scrubber unit is coupled to at least one gas / moisture vapour outlet provided at the first heating vessel and / or the second heating vessel.

14. The device as claimed in claim 13 wherein the gas / moisture vapour inlet of the scrubber unit is coupled to the at least one gas / moisture vapour outlet exclusively via at least one one-way valve.

15. The device as claimed in any preceding claim wherein the first heater and / or the second heater comprise any one or a combination of• at least one electrical resistance heating element;• a Peltier heater;• at least one heating collar positioned circumferentially around a heating zone at the respective heating chamber and / or the solid extraction conduit, the zone located between the respective inlet or intake and outlet regions.16 The device as claimed in any preceding claim wherein the first heating vessel comprises a wiper blade positioned at the inlet of the heating vessel to facilitate transfer of waste into the heating chamber.

17. The device as claimed in any preceding claim when dependant on claim 2 wherein the slurry return conduit comprises a liquid entry port to enable a liquid to be introduced into the slurry return conduit and to flow into the heating chamber of the first heating vessel.

18. The device as claimed in claim 17 comprising a mesh or screen provided at or proximate to the liquid entry port of the slurry return conduit.

19. The device as claimed in any preceding claim when dependant on claim 2 wherein the flow actuator is a pump provided in a fluid flow direction at the intake or outlet region or between the intake and the regions of the slurry return conduit.

20. The device as claimed in any preceding claim wherein the second heating vessel comprises an elongate screw conveyor rotatably mounted within the heating chamber having at least one helical blade projecting radially outward from an elongate shaft.

21. The device as claimed in claim 20 wherein a first lengthwise region of the blade axially closest to the intake region comprises a first material having a first hardness and a second lengthwise region of the blade axially closest to the outlet region of the second heating vessel comprises a second hardness being greater than the first hardness.

22. The device as claimed in any preceding claim comprising a waste intake conduit having a first end connected to or provided at the first heating vessel and a second end connected to or provided at a source of human waste.

23. The device as claimed in claim 22 wherein the waste intake conduit comprises a screw conveyor having at least one helical blade projecting radially outward from a central shaft.

24. The device as claimed in claim 23 wherein a first lengthwise region of the blade axially closest to the intake region comprises a first material having a first hardness and a second lengthwise region of the blade axially closest to the outlet region of the waste intake conduit comprises a second hardness being greater than the first hardness.

25. The device as claimed in claim 23 or 24 wherein a second lengthwise end region of the screw conveyor extends into the internal heating chamber of first heating vessel.

26. The device as claimed in claim 22 wherein the waste intake conduit comprises a tube or hose and the apparatus further comprises a pump to provide a suction force at the waste intake conduit to transfer waste through the waste intake conduit to the first heating vessel.

27. A method of processing human waste comprising: heating waste at an elongate first heating vessel having an internal heating chamber, a waste inlet, a waste outlet and a first heater positioned between the inlet and the outlet, the first heating vessel positioned in a generally upstanding or vertical orientation such that the waste is configured to transfer at least partially under gravity from the inlet to the outlet of the vessel; receiving partially dried waste at an enclosure provided at or connected to an outlet region of the chamber; and extracting a solid form of the waste by heating the waste within a second heating vessel having an internal heating chamber, an intake region provided at the enclosure, an outlet region to discharge solid waste and a second heater positioned in a waste processing direction between the intake and outlet regions.

28. The method as claimed in claim 27 further comprising: recirculating a slurry form of the waste through the heating chamber of the first heating vessel via a slurry return conduit having an intake region provided at the enclosure and an outlet region provided at the heating chamber of the first heating vessel; and driving a flow of the slurry form of the waste through the slurry return conduit.