WO2015109301A1

WO2015109301A1 - Low or no water use latrine pans, latrine pan assemblies, latrines and related methods

Info

Publication number: WO2015109301A1
Application number: PCT/US2015/011990
Authority: WO
Inventors: Gregory GATARZ; Daigo Ishiyama; James Mchale
Original assignee: AS IP Holdco LLC
Current assignee: AS IP Holdco LLC
Priority date: 2014-01-20
Filing date: 2015-01-20
Publication date: 2015-07-23
Anticipated expiration: 2016-07-20
Also published as: CN110106955A; CN106170597B; PH12016501432B1; PH12016501432A1; CN106170597A; AP2016009391A0

Abstract

The latrine pan includes a collection basin and a flapper. The collection basin has an upper bowl portion tapering from an upper rim having an outer surface to an outlet 5 extending through a wall of the collection basin at a lower portion of the collection basin. The flapper includes a counterbalance device and a coverplate disposed on opposite sides of a pivot and the counterbalance device has a plurality of counterweight arms. The coverplate has an upper face adapted to cover the outlet of the collection basin when the upper face is engaged against the lower portion of the collection basin. The flapper is pivotally mounted 10 against the collection basin such that the coverplate engages against the lower portion of the collection basin when a pivotal force attributable to the counterbalance device is substantially equal to or slightly greater than a pivotal force attributable the coverplate.

Description

TITLE OF THE INVENTION

[0001] Low or No Water Use Latrine Pans, Latrine Pan Assemblies, Latrines, and

Related Methods

BACKGROUND OF THE INVENTION

[0002] It is reported that about 2.5 billion people worldwide do not have access to any type of improved sanitation facility. These individuals and their surrounding communities suffer significant adverse health effects, including death, as a direct result of a lack of improved sanitation, including toilet facilities. Diarrheal diseases resulting from lack of sanitation are the second leading cause of child deaths in the world, claiming over 700,000 lives per year. The most affected are individuals residing in developing countries, often living in conditions of poverty outside of city centers. Such individuals do not have regular and easy access to a running fresh water supply or to facilities for the sanitary disposal of human excreta.

[0003] Because of the very real dangers posed by poor sanitation, the United Nations included access to improved sanitation as part of the Millennium Development Goals

(MDGs) established at the Millennium Summit in 2000. Specifically, Goal 7, Target 7c of the MDGs aspires to reduce by half the proportion of people without sustainable access to basic sanitation by the year 2015. "Basic sanitation" requires access to facilities that hygienically separate human excreta from human contact, such as toilets with sewer connections and septic system connections, where feasible, or pour-flush and covered slab latrines in more remote areas.

[0004] Dry open pit latrines, bucket latrines, and hanging latrines do not meet the criteria of improved sanitation, in part because the hygienic separation of the actual waste products from human contact is not ensured, but also because of the unregulated and uncontrolled release of various sewage- generated gases from these types of latrines.

Unsanitary, open latrines pose, at minimum, an olfactory challenge, as their odor is unpleasant. Although this might appear to be a purely aesthetic issue, it has public health consequences. The odor emitted from open latrines can be so offensive that the intended users actually prefer defecating in the open, placing their community at greater risk of contracting the diseases discussed above. Also of great significance is the potential for flying insects to freely enter and exit an open pit, carrying with them the hazardous pathogens the latrine is intended to contain.

[0005] In many geographies, such as areas of Africa, where water, even sullage or grey water is in scarce supply, dry use pit latrines are commonly built in an attempt to improve sanitation to some degree. However, these latrines are routinely built without specialized parts and are little more than holes in the ground. For example, a pit of about 3 to 6 feet in diameter and 4 to 10 feet in depth is formed in dirt or mud. The top of the pit is then spanned by logs or other pieces of wood except for a center section where a hole of about six to twelve inches in diameter through which waste may descend is placed. The logs may be covered with a layer of mud to create a mud-surfaced floor of the latrine. As the hole is framed only of wood and mud, its shape is too irregular and dynamic to manufacture a reliable, broadly applicable pit cover. When a suitable manual cover is provided, it is nearly impossible to ensure it is properly used at all times. Accordingly, the hole is nearly always left uncovered for at least some portion of a day, leaving a path for flying insects to transmit pathogens out of the pit and into the dwelling spaces of the community. Such latrines are considered unsanitary and unhygienic by World Health Organization standards.

[0006] Conventional pour- flush latrines can be fitted with water seals or "traps" to effectively isolate waste from human contact, but these are often not feasible for use in areas where water is scarce. For example, the quantity of water needed to flush and or clean a conventional latrine is a major concern in sub-Saharan Africa. Water, while available for human consumption in these areas is very scarce, and the source is often located some distance from the latrine. Use of even 1 liter of water per latrine use may present a severe resource burden to households. Consequently, the open pit gravity latrines described above are commonly used. While dry use pit latrines are better than having no latrines at all, they do little to eliminate the root causes of sanitation-related illnesses ~ the gases generated from decomposing human waste and the pathogen-transmitting insects which contact the waste and subsequently spread disease agents throughout the residence or community.

[0007] Thus, there remains a need in the art for latrines and latrine pans that can be inexpensively produced and distributed, that reduce the potential for pathogen transmission through flying insects, reduce odors and provide a more pleasant user experience, and which require low or no water for routine use and maintenance.

BRIEF SUMMARY OF THE INVENTION

[0008] The invention provides a latrine pan and latrine assemblies that can be used with little or no "flush water", yet provide sustainable and hygienic separation of waste from human contact. Such invention is particularly suitable and practical for use in remote, less affluent geographies where water resources are scarce.

[0009] The latrine pan includes a collection basin and a flapper. The collection basin has an upper bowl portion tapering from an upper rim having an outer surface to an outlet extending through a wall of the collection basin at a lower portion of the collection basin. The flapper includes a counterbalance device and a coverplate disposed on opposite sides of a pivot and the counterbalance device has a plurality of counterweight arms. The coverplate has an upper face adapted to cover the outlet of the collection basin when the upper face is engaged against the lower portion of the collection basin. The flapper is pivotally mounted against the collection basin such that the coverplate engages against the lower portion of the collection basin when a pivotal force attributable to the counterbalance device is

substantially equal to or slightly greater than a pivotal force attributable the coverplate. In some embodiments, the counterweight anus are disposed relative to the collection basin so that the flapper can downwardly rotate about 70 to about 95 degrees (about 90 degrees being preferred) around the pivot without contacting the collection basin, releasing any human waste present on the upper face of the coverplate into a pit latrine or other sanitary conduit.

[0010] Also included are latrine pan assemblies that include the latrine pan of the invention mounted on a stool frame so that the top surface of the latrine pan is maintained a distance above floor or ground level.

[0011] Further provided are methods of reducing the amount of water per use in a pit latrine. The method includes installing over a latrine pit the latrine pan or latrine pan assemblies of the invention, wherein the average amount of water per use required to flush the latrine pan is about 0 ml to about 150 ml.

[0012] Methods of installation using the latrine pans and assemblies of the invention, latrines including the latrine pans and assemblies of the invention and methods of sustainably and hygienically separating human waste from human contact with no or low water use are also described herein.

[0013] Further provided are waste disposal systems for use in a portable environment which includes a waste disposal conduit in fluid communication with the latrine pan or the latrine pan assembly of the invention.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0014] The foregoing summary, as well as the following detailed description of embodiments of the invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention there is shown in the drawings embodiments which may be preferred. However, that the invention is not limited to the precise arrangements and instrumentalities shown. In the drawings:

[0015] Fig. A is a photograph of an actual pit latrine presently in use in sub-Saharan

Africa; [0016] Fig. 1 is a perspective view of an embodiment of the latrine pan assembly of the invention, comprising a latrine pan mounted integrally with a stool frame;

[0017] Fig. 2 is a side view of the embodiment of Fig. 1 ;

[0018] Fig. 3 is a cut -away side view of the embodiment of Fig. 1, wherein the latrine pan is in the closed position;

[0019] Fig. 4 is a is a cut-away side view of the embodiment of Fig. 1 , wherein the latrine pan is in the open position;

[0020] Fig. 5 is a schematic plan view of an embodiment of the latrine pan of the invention;

[0021] Fig. 6, including Fig. 6A and Fig. 6B, are two schematic views of an

embodiment of the flapper, including a counterbalance device that comprises two counterweight arms;

[0022] Figs. 7, 8, and 9 schematically illustrate an embodiment of the latrine pan of the invention in use:

[0023] (i) Figure 7 is a back view of the latrine pan in the closed position before any deposit of excreta has been made to the coverplate;

[0024] (ii) Fig. 8 is a cross-sectional side view of the latrine pan immediately after deposit of excreta to the cover plate, wherein the flapper is approximately midway between closed and fully open position;

[0025] (iii) Fig. 9 is a cross-sectional side view of the latrine pan

immediately after release of excreta from the cover plate, wherein the flapper is rotated to approximately its full open position;

[0026] Fig. 10 illustrates a preferred water dispensing device that is a squirt bottle prepared from an everyday discarded PET bottle;

[0027] Fig. 11 A is a side view of an embodiment of the latrine assembly of the invention showing a stool frame that has discontinuous sidewalls and including a pull and a handle;

[0028] Fig. 1 IB is the side view of the embodiment of the latrine assembly of the invention showing a stool frame where a pull is fed through a guide tube that extends through the stool frame for access by the user;

[0029] Figures 12-19 show an alternate view of the embodiment of Fig. 1 :

[0030] (i) Fig. 12 is a perspective view of an embodiment of the latrine pan assembly of the invention;

[0031] (ii) Fig. 13 is a side view of the latrine pan assembly of Fig. 12;

[0032] (iii) Fig. 14 is a top plan view of the latrine pan assembly of Fig. 12; [0033] (iv) Fig. 15 is a front view of the latrine pan assembly of Fig. 12;

[0034] (v) Fig. 16 is a bottom view of the latrine pan assembly of Fig. 12;

[0035] (vi) Fig. 17 is a side oriented perspective view of the latrine pan assembly of Fig. 12 wherein a portion is cut away along DR-DR;

[0036] (vii) Fig. 18 is a right side view of the N latrine pan assembly of Fig. 12 in a cross section taken along DR-DR, in a closed position; and

[0037] (viii) Fig. 19 is a right side view of the latrine pan assembly of Fig. 12 in a cross section taken along DR-DR in an open position.

[0038] Figs. 20 to 25 show an alternative of the latrine pan assembly of the invention which may be useful for installation in cement slabs or in earthwork terraces:

[0039] Fig. 20 is a top perspective view of an alternative embodiment of the latrine pan assembly;

[0040] Fig. 21 is a top plan view of the embodiment of Fig. 20;

[0041] Fig. 22 is a rear elevational view of the embodiment of Fig. 20;

[0042] Fig. 23 is a bottom plan view of the embodiment of Fig. 20;

[0043] Fig. 24 A is a side view of the embodiment of Fig. 20;

[0044] Fig. 24B is a side view of an embodiment of Fig. 20, wherein the embodiment includes a pull, and the pull is contained in a guide tube that extends though the platform; and

[0045] Fig. 25 is a bottom perspective view of the embodiment of Fig. 20.

DETAILED DESCRIPTION OF THE INVENTION

[0046] The invention described herein includes a low or no water use latrine pan that can be mass produced and transported to remote areas at relatively low cost. When used properly, the latrine pan of the invention prevents flying insects from passing in and out of the pit, prevents or reduces the backflow of odors and sewage gases. Most significantly, the invention is suitable and practical for use in remote geographies where water is scarce and precious.

[0047] In daily use, the latrine pan of the invention and the related latrine pan assembly requires a negligible (low) amount or no water to flush, by virtue of the structure and placement of the counterbalance device and/or use of the pull element (discussed further below).

[0048] Also contemplated within the scope of the invention are latrines incorporating the latrine pan and/or latrine pan assembly, methods of installing the latrine pan, and methods of sustainably and hygienically removing human waste from human contact with no or low use of water. The latrine pan and/or assembly may also be used in non-latrine waste disposal applications, such as in mobile or portable waste disposal systems found in, e.g., boats, cars, RVs, campers, airplanes, etc.

[0049] Each aspect of the invention is described in detail below.

[0050] The invention in some embodiments will be described with reference to the drawings provided herein. In the specification, words such as "inner" and "outer," "upper" and "lower," "superior" and "inferior," "distal" and "proximal", "inwardly" and

"outwardly," and "uppermost" and "lowermost," and words of similar import are used for assisting in the understanding of the invention when referring to the drawings and absent a specific definition or meaning otherwise given by the specification for such terms, should not be considered limiting to the scope of the invention.

[0051] The invention includes a latrine pan that includes a collection basin and a flapper. The collection basin may be of any size, design or shape known or to be developed in the art. For example, the collection basin design may be circular, oval, square, kidney- shaped or triangular when regarded in plan view. As will be understood in the art, numerous latrine pan designs have been developed based upon cultural and habitual preferences and any of these designs may be employed in the present invention. Regardless of the specific shape, it may be preferred that the design/shape of the collection basin be adapted to reducing urine splashing, facilitate pit-directional flow of excreta and sanitary products with minimal water flow, permit assumption of a comfortable deposit position by adults, and/or be on a scale that can be safely used by children. Because the latrine pan of the invention is designed, in certain embodiments, to be used with a stool frame, creating a Western-style toilet stool, the size and shape of the latrine pan may also be varied depending on its intended end use is alone or in conjunction with the stool frame. For example, the upper rim of the collection basin of the latrine pan or the upper edged of the stool frame may include a flange that extends laterally and can act as a toilet seat to support the hind region of an individual who uses the latrine pan in conjunction with the stool frame. This aspect of the invention is discussed in more detail below.

[0052] In an embodiment, the collection basin of the pan includes a bowl having a radially extending elongated portion, such that the collection basin's top plan view resembles a stylized egg or ovoid shape (see, e.g., Figure 1). In an embodiment, it may be preferred that the elongated portion extends from the upper bowl portion only, so that the collection basin has a non-uniform depth, with the bowl of the basin through which an outlet extends being deeper.

[0053] It may be preferred that the collection basin has a capacity of about 3 to about 15 liters, to ensure safe and spill-less receipt of human waste and of the flush or cleaning water, if such is used. In an embodiment, it may be preferred that the collection basin has a length dimension of about 9 inches (23 centimeters) to about 22 inches (56 centimeters) and, independently, the width dimension may be about 6 inches (15 centimeters) to about 16 inches (41 centimeters). Smaller sizes within this range would be desirable for application where primary use by children is foreseeable, such as in schools.

[0054] The collection basin may be manufactured as an integral piece or it may be manufactured in components (of the same or of different materials) that are subsequently assembled. The collection basin may be cast, molded, thermoformed, stamped, carved or otherwise formed, depending on the material selected. Any material known or to be developed in the art may be used, such as, without limitation, a polymer, a plastic, a composite, a metal, a concrete, a cement, a natural or synthetic stone, a composite, a wood, a fiberglass, a marble, a porcelain, a ceramic, gravel, and a clay. It is preferred that the material selected is durable, resistant to crazing, and smooth surfaced.

[0055] The collection basin may be formed of a first material, and then coated with one or more of a second material to realize desirable surface properties. For example, the collection basin may be made of a fiberglass material that is coated with an adherence- reducing material (for example, polytetrafluoroethylene (TEFLON®)) to increase the ability to maintain a clean, excreta-free surface or an antibacterial coating, such as nanoparticles of titanium dioxide, silver, copper, gold, and/or gallium.

[0056] In some embodiments, the material of the collection basin is a thermoplastic or thermoset polymer or copolymer as such materials are durable, relatively inexpensive and easy to fabricate and to clean. Suitable plastics may include polyethylene terephthalate, high-density polyethylene, polyvinyl chloride, low-density polyethylene, polypropylene, polystyrene, polyvinylidene chloride, high impact polystyrene, polyamides, acrylonitrile butadiene styrene, polyethylene/acrylonitrile butadiene styrene, polycarbonate,

polycarbonate/acrylonitrile butadiene styrene, polyurethanes, melamine formaldehyde, phenolics, polyetheretherketone, polyetherimide, polymethyl methacrylate,

polytetrafluoroethylene, and/or urea- formaldehyde.

[0057] Regardless of the shape or size selected, the collection basin includes a bowl, an upper portion of which having walls that taper downwardly to an outlet. The outlet extends through a wall of the basin, preferably a wall in the lower portion of the basin. The slope of the taper may be steep or gradual, depending on the design and shape of the overall collection basin. Preferably, as noted above, the slope is adjusted to minimize splashing from the sidewalls and to facilitate progress of excreta and other waste through the outlet. [0058] The outlet may be, for example, a simple hole defined by the lowermost sidewall of the basin or a conduit defined by the narrowing of the basin sidewalls of the lower portion of the basin. In some embodiments, the outlet is defined by a structure that is adapted to be fitted to pipe or conduit, so that the latrine pan and the leach pit may be sited apart but remain in fluid communication. In an embodiment, the outlet has a diameter of about 2 inches to about 5 inches, although outlets of any dimension may be used. The most suitable dimension may be one large enough to permit egress of the non-standard toilet paper substitutes used in the region where the latrine is to be installed but not so large that it poses a danger to small children.

[0059] The latrine pan of the invention also includes a flapper. The flapper itself includes a counterbalance device and a coverplate that are disposed on opposite sides of a pivot relative to one another. As noted with the collection basin, the flapper can be manufactured as one piece or as several pieces that are subsequently assembled together. The flapper or its component parts may be made of any of the materials discussed above as suitable for the collection basin, including coatings and additional surface treatments.

[0060] Since the latrine pan of the invention is designed to permit disposal of waste into the latrine pit with little or no water, it may be particularly desirable that at least the upper face of the coverplate is composed of or is coated with an adherence-reducing material, that is, a material that reduces the adherence of excrement to the coverplate upper face to make it slippery, permitting release with minimal application of force. Adherence-reducing materials may include those listed above in connection with the collection basin, or less permanent alternatives, such as oils or gels that are applied to the upper face of coverplate periodically or with each use.

[0061] The coverplate may be disc or plate shaped, or it may be any other geometry that serves to completely cover the waste hole defined by the outlet or opening in the lower portion of the collection basin and create a mechanical seal. In an embodiment, the coverplate may be cup shaped and is adapted to cover the outlet of the collection basin when the coverplate is engaged against the lower portion of the collection basin. For example, the coverplate may be in the form of a hollow cylinder with a closed bottom, such that it cups the outlet or the lower portion of the collection basin to form a mechanical seal when engaged against the outlet or lower portion of the collection basin. The sidewalls of the closed bottom cylinder or cup extend upwardly to capture a small amount of water on the coverplate upper face and create an airtight water seal when the flapper is in closed position.

[0062] In some embodiments, these sidewalls may extend about 0.5, about 1 , about 1.5, about 2, about 2.5 inches from the closed bottom. Independently, the sidewalls of the cup may be flared as they extend upwardly, that is, the diameter of a cross section of a bottom portion of the cup may be smaller than a cross section of an upper portion of the cup.

[0063] In various embodiments, the coverplate may be of an ordered geometric or random shape when viewed in plan. For example, the coverplate may have a square, rectangular, triangular, etc., shape when viewed in plan.

[0064] As noted above, under everyday use of the latrine pan, several milliliters of liquid may remain residing in the coverplate after flushing or cleaning, forming a liquid seal between the surface of the coverplate and the lower portion of the basin. The seal in conjunction with the mechanical seal serves to prevent, reduce and/or ameliorate the backflow of gases from the leach pit into the environment of the residence or squatting room. Such reduction may be at least by 50%, by 80% or by 90% or more as compared to an uncovered leach pit or waste disposal pit. Advantageously, the seal may also prevent entry of most types of insects into the living environment or into the leach pit, blocking a major transmission route for diseases. Moreover, the counterweighted design ensures that the entrance to the pit is automatically sealed, requiring no user intervention.

[0065] When using the latrine pan, the flapper is pivotally mounted against the collection basin. The coverplate and counterbalance device are disposed on opposite sides of the pivot. In an embodiment, the pivot is substantially equidistant between the coverplate and the distalmost ends of each of the counterweight arms of the counterbalance device; it may be placed in other locations along the flapper if desired.

[0066] The coverplate is located so that it covers the outlet, as described above, and on the other side of the pivot is located the counterbalance device. The flapper "teeter totters" between a closed state (where the coverplate is engaged against the lower portion of the basin) and an open state (where the coverplate and the lower portion disengaged and spaced apart to permit egress of excreta and other waste into the leach pit). Whether the flapper is in an "open" or a "closed" state depends on which end of the flapper is experiencing the greater pivotal force.

[0067] When in fully open position, it may be desirable that the flapper has rotated about 80 degrees, about 90 degrees, and about 95 degrees, around the pivot relative to the flapper's initial location in the closed position. Such ability to rotate to these extents facilitates the release of waste from the upper surface of the coverplate with no or low use of water.

[0068] Accordingly, the structure of the counterbalance device is adapted to permit this extensive rotation of the flapper and to avoid contact with and/or hindrance by the collection basin upon rotation. In practice of the invention, the counterbalance device serves to maintain the closed state of the flapper by exerting a pivotal force that is slightly greater or substantially equal to any counter pivotal force experienced by the coverplate when the coverplate is vacant (and/or contains small amount of water forming the water seal), thus maintaining the closed position of the flapper. Conversely, the counterbalance device should be adapted to avoid exerting a pivotal force that is greater than the force exerted by an average waste quantity deposited on the coverplate. The counterweight arms are weighted and positioned such that the pivotal force required to re-engage the flapper in a closed position is decreased as the flapper rotates and the coverplate opens (i.e., the center of gravity moves closer to the pivot as the counterplate disengages). As will be appreciated in the art, the optimum weight/mass of the counterweight arm and/or the counterbalance device overall will vary depending on the scale of the latrine pan and flapper as well as the location of the pivot relative to the placement of the counterweight arms of the

counterbalance device. Any such adjustments are well within the purview of a person of ordinary skill in the art and/or common sense.

[0069] In an embodiment, the counterbalance device comprises at least 2, at least 3, at least 4, at least 5 and at least 6 counterweight arms. The counterweight arms may extend from any point on the flapper but are preferable on the non-coverplate side of the pivot. Regardless of number, the counterweight arms shaped and/or are disposed on the flapper and relative to the collection basin so that even when the flapper is rotated about 80, about 90, or about 95 degrees from its initial position, the counterweight arms will not contact or be hindered by the collection basin.

[0070] The arms may be of any shape or dimension. In an embodiment, the counterweight arms are disc shaped and mounted on actuate extending members that are in turn attached to the flapper {see, e.g.. Fig. 6). In another embodiment, the counterweight arms are in the form of actuate or fin-like shapes that inversely mimic the outer contours of the collection basin, and can be disposed on the flapper to allow for 80 degree or greater rotation of the flapper without encountering the sidewalls of the collection basin.

Alternatively, the counterweight arms may together form a wishbone-like shape when viewed in plan form {see, e.g., Figs. 3 and 4).

[0071] The counterweight arms may be solid (weighted) as manufactured, they may be in the form of hollow containers that may be filled with weight material at the location of latrine construction, or they may be weight materials found at or brought to the latrine construction site and affixed to the flapper on site. For example, the counterweight arms may include a rock, brick or block of suitable sized or mass found on site as the latrine is constructed that is affixed to the flapper. The counterweight container could also be fom ed to accept a lid or cover, in which case sand, water, or other similar materials could be used.

[0072] As noted above, the specific masses of individual the counterweight anus will vary on a case-by-case basis depending on the amount of pivotal force that the

counterbalance device must exert, which in turn is a function of a variety of variables such as the scale of the latrine pan and flapper combination and the number and relative placement of the counterweight arms.

[0073] In an embodiment, the counterweight arms are of a weight and placement such that the counterweight arms exert a pivotal force that is less than the pivotal force exerted by a combination of the coverplate and an average waste quantity deposited on the coverplate. In some embodiments, when the average waste quantity is deposited, the flapper may immediately begin to rotate to full open position to allow the waste to fall into the latrine pit. By "average waste quantity" it is meant about one average bowel movement or an amount of urine generated in one urination event from a reasonably healthy individual suffering from no significant gastrointestinal or urinary disorders. If, for some reason, the pivotal force resulting from the deposit of the waste on the coverplate is insufficient to actuate complete opening of the flapper, the pivotal force applied may be increased by application of a negligible amount of water to the coverplate by the individual user. In an embodiment, the amount of water applied is about 80, about 100, about 150 ml.

[0074] Alternatively, the rotation may be effectuated by use of the pull, discussed below.

[0075] Regardless of the choice of counterbalance device or design, it is preferable that the center of mass of the counterweight arms be positioned above the pivot of the flapper. Doing so ensures that the closing force decreases, rather than increases, as the flapper opens. This, in turn, ensures that the flapper will swing to its full open position whenever the initial closing force is exceeded, thereby allowing waste to more easily slide off of the upper face of the coverplate of the flapper and into the pit.

[0076] In some embodiments, it may be preferred that water is applied using a "squirt bottle" or another similar manual water dispensing vessel that dispenses water at a higher water pressure than is generated by simple pouring. By "squirt bottle" it is meant a bottle having flexible sidewalls and an neck orifice with a diameter Di, such neck orifice being closed with a cap containing a squirting hole with a diameter D₂, and Di > D₂. It may be preferred that Di is 30-350% than D₂. Upon manual application of force to the flexible sidewalls of the bottle, water is propelled first though the neck orifice, then through the squirting hole. The water exiting the squirting hole is delivered at a higher pressure (and therefore exerts a greater pivotal force) than it would have had if it had simply been poured onto the coverplate.

[0077] The flapper which facilitates the opening and closing of the outlet is pivotally mounted against the collection basin so that the coverplate engages against the lower portion of the basin. The flapper may be pivotally mounted directly to the basin (for example, to its exterior), or it may be mounted on a nearby structure (such as a wall or post). The pivot may take the form of any known or to be developed in the art. For example, without limitation, the pivot may be an arrangement of aligned holes in the flapper and the basin and pins; the flapper may include a loop through which a baton is inserted, allowing for pivotal rotation; the pivot may be a flexible bracket on the underside of the basin through which the flapper is threaded, or the pivot may be a fulcrum inserted beneath the flapper.

[0078] In an embodiment, the latrine pan includes a "pull" or multiple pull that is/are attached to and extend(s) from the flapper, preferably on the counterbalance side of the pivot. When force is applied to the pull by the user, the flapper is pivoted about the pivot to displace the coverplate from the closed position. In some embodiments, the pull extends through an orifice extending through the sidewall of the stool frame or an area of the platform of the latrine pan assembly.

[0079] The pull may be attached to a handle that is of a size or shape that renders it incapable of passing back through the orifice and falling into the pit. Additionally or alternatively, the pull or the pull handle may be attached to the latrine pan assembly or to an adjacent structure.

[0080] The pull itself may be formed of any material, rigid or flexible; materials such as string, wire, cable or rope, braided, mono- or multi-filament may be preferred. In an embodiment, the pull may be 100 lb test weight fishing line. The pull can also take the form of a rigid rod manufactured from, e.g., plastics, wood, metal, or other material. Although a straight line orientation of the pull may be preferred for simplicity, it is also possible to incorporate pulleys, levers, or other well-known mechanisms to relocate the user interface for the pull, adjust the required opening force, or improve reliability of the linkage.

[0081] In some embodiments, the latrine pan assembly may include a guide tube through which the pull extends to avoid wear and/or soiling of the pull. The guide tube make take the form of an elongate hollow structure, such as a cylinder having a hollow interior of sufficient volume that the pull can be freely pulled out of, and retract back into, the guide tube. The guide tube may extend upon substantially the entire length of the pull or it may extend along only a portion of the pull. The guide tube may be made of a rigid or flexible material. It may be formed unitarily with the latrine pan assemble (or a component of the latrine pan assembly) or it may be formed separately.

[0082] In an embodiment, the latrine pan is attached to (or integral with) a stool frame to form a latrine pan assembly. The frame may take any form as long as it is a structure that maintains the latrine pan in an elevated state relative to the floor or ground surface. In an embodiment it is preferred that the stool frame elevates the latrine pan so that a person of average height can sit or partially squat over it with relative comfort.

[0083] For example, it may be preferred that the stool frame elevates the top surface of the latrine pan to about 5 inches to about 20 inches or to about 8 inches to about 25 inches above the plane of the floor or ground surface (herein after collectively "the standing surface"). Ideally, the stool frame provides a generally continuous barrier between the latrine pan and the mounting surface for the installation so that the system can form an essentially airtight seal over the opening to the pit. It is preferable that the stool frame include an outwardly extending base flange to assist in securing the stool to the latrine floor. The flooring material (mud, concrete, plaster, or the like) may be built up above the base flange to provide said seal and securement.

[0084] In an embodiment, the latrine pan and the stool frame are manufactured separately, and later assembled, for example, by affixing the latrine pan to the stool frame at the collection basin's upper rim. Alternatively, the latrine pan or portions of the latrine pan may be formed integrally with the stool frame or portions of the stool frame.

[0085] In an example, the upper rim of the collection basin of the latrine pan may include a flange that extends laterally and is attached to the stool frame, either at the flange's distalmost edge or at some intermediate location on the flange. In such

embodiment, the flange can act as a toilet seat to support the hind region of an individual who uses the latrine pan in conjunction with the stool frame, resulting in increased comfort. Such a construction would also enable the latrine pan to be installed into a floor to accommodate use in a squatting position.

[0086] The frame stool may be, for example, an open-ended column in to the upper portion of which is mounted the latrine pan, with or without a flange. The column may have continuous or discontinuous sidewalls. In an exigent circumstance, the open-ended column may be formed from a five gallon plastic pail, such as those commonly used for food storage, paints, chemicals, etc., and which may be salvageable in a remote location. The pail is inverted and a hole sufficient to fit the latrine pan of the invention is created in the closed bottom of pail. The walls of the pail form the sidewalls of the stool frame. [0087] Other forms of the stool frame may be used, for example, the latrine pan may be affixed to and supported by three or more legs; the latrine pan may be incorporated into in a conventional furniture type stool (i.e., a bar stool or ottoman type tool); the latrine pan may be incorporated into a bench structure. The stool frame may be made of any material known or to be developed in the art. Suitable materials include those that are listed as appropriate for the latrine pan, above.

[0088] This embodiment (like all others disclosed herein) may also include a guide tube and/or a pull(s) as described above, to manually open the counterweighted door. The pull can be located at a rear side position or can be placed in a frontal position with the use of an additional guide tube or guide orifices to direct the pulling force upwardly on the counterweight.

[0089] In an alternative embodiment, the latrine pan is attached (or integral with) a platform. Such assembly may be particularly useful if one wishes to install the latrine pan in or on a cement slab or within or on an earthworks terrace. The platform is attached to or an extension of a laterally extending flange that extends from the upper rim of the latrine pan. When viewed in plan, the platform may take any shape or configuration - rectangle, circle, ellipse, oval, trapezoid, pear-shaped, hexagon, square, etc. In some embodiments, the platform when viewed in plan has an irregular polygon shaped or an irregular circular or elliptical shape.

[0090] The platform (and the attached latrine pan) may be mounted on any surface surrounding the opening of a leach pit, such as for example, a decking type surface made of wood, composite or the like, a cement or tarmac slab, packed earth, etc. In some embodiments, the platform may include devices that permit securment of the platform to the surface, such as, for example, holes, hooks, ties, flaps, tabs, etc.

[0091] The platform has a top surface and a bottom surface, and may be of any surface area. The thickness of the platform (i.e., the vertical distance from the top surface to the bottom surface) may vary, depending on the end use of the assembly. In some

embodiments, it may be preferred that the thickness is about 1 inch to about 10 inches, about 3 inches to about 7 inches, or about 5 inches.

[0092] In an embodiment, the top surface is substantially planar. In some embodiments it is smooth; alternatively, the top surface may include non-smooth topography to prevent slippage of the individual using the latrine pan. For example, at least portion of the top surface of the platform may include roughed areas (increasing friction), anti-slip bumps, ruggae, indentations, protrusions, and the like to reduce the chance that a user will slip on the platform, even if the platform is wet. [0093] In an embodiment, the bottom surface is overlayed with a grid or lattice. Such grid or lattice may function as structural reinforcement and/or may facilitate attachment of the assembly to or within the cement or earth upon installation. The grid/lattice may be formed unitarily with the platform, or it may be applied by a separately. Alternatively, protrusions, extensions, pins, fins, baffles, and like structures may extend from the bottom surface, to allow for attachment of the assembly to/within cement or earth.

[0094] The platform may also be fitted with a pull for manually opening its door. A guide tube may be used to eliminate interference and wear resulting form excessive friction to the pull in varying and uncontrolled installation conditions. In this embodiment, the guide tube may be preferably made out of a flexible material, and extends through the flange or platform. The guide tube (in this or any embodiment) may be flared at one or more of its ends, for example, at the outside end to maintain it in its desired location and avoid its slipping below the plane of the flange or platform.

[0095] A non-limiting embodiment of the latrine pan of the invention, the latrine pan assembly of the invention and the practice of the same is illustrated in Figures 1-19.

[0096] With reference to these Figures, a latrine pan assembly 100 that includes a latrine pan 102 and a stool frame 104 is provided. In this embodiment, the latrine pan and the stool frame are shown in these Figures as being formed integrally; that is, they were molded as one piece.

[0097] The latrine pan 102 includes a collection basin 106 and a flapper 108. The collection basin 106 includes an upper bowl portion 1 10 that tapers from an upper rim 1 12. In this illustrative example, the upper rim 112 includes a laterally extending flange 1 14 that encircles the perimeter of the upper rim 1 12. The flange 114 extends to the upper edge 116 of the stool frame 104, providing a toilet seat-like perch for the latrine assembly user. The flange may include an orifice 168 through which a pull or guide tube and pull may extend. The collection basin 106 includes a lower portion 118. An outlet 122 extends though a wall 120 of the lower portion 1 18 of the collection basin 106.

[0098] The latrine pan 102 further includes a flapper 108 that in turn includes a coverplate 124 and a counterbalance device 126, each disposed on opposite sides of a pivot 128. In the embodiments shown in the Figures, the flapper 108 is pivotally mounted to the exterior 130 of the collection basin 106. The pivot 128 is an aligned holes-and-pin configuration; a first set of holes 132, 132' (not visible) extends through an extension body 136 (not visible) of the flapper 108, and a second set of holes 134, 134' (only one visible) are present in a spaced bracket 138, 138' (only one visible) on the exterior 130 of the collection basin 106. [0099] The counterbalance device 126 of the flapper 108 includes two counterweight arms (139,139') that are affixed to the flapper 108. In one of the embodiments shown (e.g., Figs. 1-4), the counterweight arms together form a wishbone-shaped counterbalance device 296. In the second embodiment shown (e.g., Fig. 6) the counterweight arms are in the form of weighted discs 142, 142' mounted on arcuate extending members 144, 144' that are in turn attached to the flapper 108.

[00100] In one of the embodiments shown (Figs. 1-4), the coverplate 124 of the flapper 108 takes the form of a shallow cup (i.e., a cup with short sidewalls). The sidewalls 140 of the coverplate 124 permit formation of a liquid seal against insects and sewages gases even when a low amount of water (50 ml or less) is present in the coverplate 124.

[00101] In the closed state, the flapper 108 causes the coverplate 124 to engage against the outlet 122 of the collection basin 106 covering the outlet 122 and forming a simple mechanical seal at the parts' interface. The outlet 122 shown in this embodiment has a substantially circular cross section; thus the bottom 146 of cup-shaped coverplate 106 is substantially disk shaped to cover the outlet 122.

[00102] As noted above, an upper edge 1 16 of the stool frame 104 is attached to the distalmost end of the flange 1 14. The sidewall 148 of the stool frame 104 extends downwardly from the upper edge 116 towards the standing surface (not visible; the surface, dirt or indoor floor, on which the stool frame will be placed). In the embodiment shown, the sidewall 148 tapers outwardly as it descend downwardly to increase stability of the stool frame 104. The sidewall 148 terminates in a bottom edge 150 around the perimeter of which extends a foot flange 152, which enhances stability and serves to anchor the latrine assembly over the pit if buried in the surrounding mud/dirt.

[00103] Figure 11 A shows an alternative stool frame 104, wherein the sidewall 148 is discontinuous and the flapper 108 is capable of being rotated by a pull 160 that extends though an orifice (not visible) in the sidewall 148 of the stool frame 104. The pull 160 extends trough the orifice and is attached to a handle 178 to enable "flushing". In an embodiment, the pull 160 may extend from the flapper 108 through an orifice located in the upper edge 116 or flange 1 14, or the upper portion 162 of the sidewall 148, as shown. * When not is use, the terminal end 161 of the pull 160 may be free as shown in the Figure, or it may be secured to the assembly or to an adjacent structure.

[00104] Figures 5 to 9 provide an exemplary illustration of a specific embodiment of the latrine pan assembly in use. Fig. 5 is a schematic top plan of the latrine pan assembly 100, showing the latrine pan 102, collection basin 106, its upper rim 1 12, extending flange 114 and the waste hole 154 defined by the walls of the outlet 122. Figure 6 illustrates the flapper 106 detached from the latrine pan, including the coverplate 124, flapper extension body 136, counterweight arms in the form of arcuate extending members 144, 144' and weighted discs 142, 142' and a pivot pin 156 placed in holes (not visible) located in the extension body 136.

[00105] Figure 7 illustrates a back cutaway view of the latrine assembly of the invention when the flapper 108 is in closed position and showing the relative position of the counterweight arms 239, 239' and the wall 120 of the collection basin 106. In Figure 7 (and 8), it is seen that the latrine pan 102 is mounted on a stool frame 104 which elevates the top surface 180 of the latrine pan 102 above ground or floor level.

[00106] Figure 8 shows a side view cross section of the latrine assembly 100

immediately after deposit of an average waste amount 158, wherein the pivotal force exerted by the deposit exceeds that exerted by the counterbalance device 126 and initiates rotation of the flapper 108 from the closed position to the open position.

[00107] Figure 9 illustrates the latrine pan assembly 100 in a side view cross section in a substantially fully open position. As can be seen, the flapper 108 has been rotated around the pivot 128 about 75-85 degrees (Angle A= about 75-85 degrees), facilitating release of the average waste amount 158 from the upper face 162 of the coverplate 124 to descend through the cavity 164 defined by the stool frame 104 and in to the latrine pit (not visible). If the flapper 108 does not rotate a sufficient amount to the release the average waste amount 158, additional pivotal force may be applied via a water stream applied by dispensing vessel, such as a squirt bottle.

[00108] Fig. 10 illustrates a suitable "squirt bottle" water dispensing vessel made from a discarded PET water bottle 166 having flexible sidewalls 168. The bottle 166 has a neck orifice 170 with a diameter Di. The bottle 166 is filled with water 177 and capped with the cap 178 having a squirting hole 179 for dispensing water. The diameter of the squirting hole (D₂) is significantly less than Dj. The squirt bottle may be used with any latrine pan/latrine pan assembly as described herein.

[00109] Figures 20 to 25 show an alternative embodiment in which a latrine pan is attached to a platform to form a latrine pan assembly 200. Referencing these figures, the latrine pan 202 shown therein includes a collection basin 206 and a flapper 208. The collection basin 206 includes an upper bowl portion 210 that tapers from an upper rim 212.

In this illustrative example, the upper rim 212 includes a laterally extending flange 214 that encircles the perimeter of the upper rim 212. The flange 214 extends to a platform 280, which can be used to secure the latrine pan 202 to a cement slab or earthwork terrace and can be stood/squatted upon when the assembly is in use. The collection basin 206 includes a lower portion 218. An outlet 222 extends though a wall 220 of the lower portion 218 of the collection basin 206.

[00110] The latrine pan 202 of the assembly 200 further includes a flapper 208 that in turn includes a coverplate 224 and a counterbalance device 226, each disposed on opposite sides of a pivot 228. In the embodiment shown in the Figures, the flapper 208 is pivotally mounted to the exterior 230 of the collection basin 206. The pivot 228 is an aligned holes- and-pin configuration; a first set of holes (not visible) extends through an extension body 236 of the flapper 208, and a second set of holes are present in a spaced bracket 238, 238' (only one visible) on the exterior 230 of the collection basin 206.

[00111] The counterbalance device 226 of the flapper 208 includes two counterweight arms (239, 239') that are affixed to the flapper 208. In this embodiment the counterweight arms together form a wishbone-shaped counterbalance device 296. The bottom surface 281 of the wishbone-shaped counterbalance device 296 is overlayed with a lattice 283 that serves to add material and provide mass to the counterweight. The counterweighted flapper device is applied to the bottom surface 281 at installation. In this embodiment, the lattice 283 was formed unitarily with the wishbone-shaped counterbalance device 238; however, in other embodiments, the lattice may be formed separately. In alternative embodiments, other materials, for example concrete, steel fittings, etc., can be inserted to provide an optimal mass to the counterbalance device.

[00112] In this embodiment, like the others described herein, the coverplate 224 of the flapper 208 takes the form of a shallow cup (i.e., a cup with short sidewalls). The sidewalls 240 of the coverplate 224 permit formation of a liquid seal against insects, sewages gases, and unpleasant odors, even when a low amount of water (50 ml or less) is present in the coverplate 224.

[00113] In the closed state, the flapper 208 causes the coverplate 224 to engage against the outlet 222 of the collection basin 206 covering the outlet 222 and forming a simple mechanical seal at the parts' interface. The outlet 222 shown in this embodiment has a substantially circular cross section; thus the bottom 246 of cup-shaped coverplate 206 is substantially disk shaped to cover the outlet 222.

[00114] In the embodiment shown in Figures 20-25, the laterally extending flange 214 is integral with the platform 280, which has a top surface 282 and a bottom surface 284. The platform 280 extends from the laterally extending flange 214 to an outer edge 286. In this embodiment, a sidewall 288 extends substantially downwardly and terminates in a sidewall bottom edge 290. In this embodiment, a flange edge 292 extends substantially laterally from the sidewall bottom edge 290 to increase stability of the platform 280 and provide a surface for mounting to a wood, mud, concrete or other floor or structure.

[00115] A portion of the top surface 282 which corresponds approximately to the areas where a user may place his or her feet when using the latrine pan assembly 200 includes anti-slip devices 294 arranged substantially uniformly along either side of the latrine pan 202. For this exemplary embodiment, each of the anti-slip devices 294 is an upraised extended kidney shaped device. However, any anti-slip device may be used.

[00116] The bottom surface 284 of the platform 280 is overlayed with a lattice 298 extending to an outer edge 300 that substantially corresponds to the outer edge of the 286 of the platform 280. In this embodiment, the lattice 298 is formed unitarily with the platform 280; however, in other embodiments, the lattice may be formed separately.

[00117] With reference specifically to Figure 1 IB, in this embodiment, the assembly may include a pull 160 extending from a flapper 208 through the top surface 282 of the platform 280. The pull 160 is enclosed within a guide tube 172. A bottom portion 176 of the guide tube 172 extend below the platform 280 and an upper portion 174 extends above the top surface 282 of the platform 280, passing through the orifice (not visible).

[00118] The latrine assemblies that may be provided to latrine builders or householders include the latrine pans described herein with the frames, as well as a water dispensing vessel, and other optional article, including communication or written materials.

[00119] A latrine of the invention employing the latrine pan or the latrine pan assembly as described herein can be sited in a public structure, such a marketplace public facility, a family residence or may be situated outside a family residence is a separate superstructure (a so-called "outhouse"). Preferred dimensions of the room or structure are about 800 mm by about 1000 mm or greater. The latrine may be configured by locating the latrine pan or latrine assembly immediately above a leach pit. The structure and design of leach pits are well established in the art and will vary depending topographical, cultural, and

environmental conditions. Such adjustments are well within the skill set of a person of ordinary skill in the art and will not be repeated herein.

[00120] In an embodiment, the latrine pan of the invention inserted in a flat panel base, so that, for example, the upper rim of the latrine pan is substantially flush with the upper planar surface of the panel base. The base would preferable have a smooth surface that is non-absorbent and easily cleanable. Material of which the base may be made include plastics, metals, coated metals, fiberglass, stone, cement, polished cement, etc. In some embodiments, the base may be of a sufficient strength that it can be used by simply mounting it over the pit with no need for a subfloor. In any latrine configuration an optional latrine pan cover may be provided to cover the latrine pan when not in use, although with the present invention, the benefit of the cover would be more aesthetic than functional, as the counterweighted flapper ensures hygienic closure of the pit.

[00121] Once installed, the latrine can be easily operated and maintained. To use the latrine, the user squats over the collection basin of the latrine pan or sits over the latrine assembly, first removing the latrine pan cover, if one was present. Since the latrine pan is initially empty except for the small amount of water that creates the water seal, the latrine pan is in the closed position. The user deposits the waste, which is conveyed by gravity to the upper face of the coverplate. Ideally, when the waste contacts the coverplate, the flapper will immediately begin to pivot about 70 to 90 degrees and the waste will be released from the coverplate and descend into the pit with no use of water. If necessary, the user may apply a stream of a small amount of water (80-150 ml) to the coverplate to facilitate pivoting of the flapper and remove any adhered waste using the vessels described above. The water may be non-potable water, such as unpurified river water, sullage or grey water. In an embodiment, the user may facilitate the pivoting of the flapper by tugging on the pull, which is attached to the flapper, also described above. In preferred embodiments, the pull mechanism is utilized in a latrine pan with a generally larger flapper coverplate of about 100-300 mm in diameter. In such a system, the user can use the pull mechanism to open the flapper before depositing waste, preventing waste from contacting the upper face of the coverplate and allowing for an absolute minimum in water usage.

[00122] Once the waste is released from the coverplate, the flapper returns to closed position. In most instances, if water was used, sufficient liquid residue should remain in the pan to create the liquid seal. In the event that water was not used, the pan can be rinsed using a small amount of water (80-150 ml) and a new water seal created. If the liquid forming the seal evaporates under hot weather conditions, an additional aliquot of liquid can be applied to restore it.

[00123] The water dispensing vessel used to apply the water stream that flushes the latrine pan may be any known or to be developed in the art. It may include a bucket, a scoop, a ladle, a pail, a spout-bearing vessel, a hose, and an expandable bladder. In some embodiments, one may prefer that the water dispensing vessel is sized to dispense only a pre-determined amount of water, to conserve water and to avoid over-flow of the leach pit. For example the water dispensing vessel may be chosen from those that have liquid volume capacity selected from about 25 ml, about 50 ml, about 100 ml, about 150 ml. As noted above however, it may be preferred that the dispensing vessel is a squirt bottle. [00124] In practice, the latrine pan described herein may be assembled with a water dispensing vessel, and optionally, written or digital materials and distributed as a latrine pan assembly for installation into a latrine. The written or digital materials may include a communication device that provides at least one of (a) instructions for assembly of the latrine pan, (b) instructions for installation of the latrine pan, (c) instructions for use of the latrine pan assembly, and (d) instructions for maintenance of the latrine pan assembly. Such information may be presented in a language and cultural style suitable for the area in which the assemblies are to be distributed.

[00125] All the latrine pans and latrine pan assemblies described herein may be used in other non-latrine applications, such as in portable, moveable or non-permanent waste disposal systems or environments. For example, the latrine pan and latrine pan assemblies described herein may be used in waste disposal systems that include a waste disposal conduit in fluid communication with the latrine pans or the latrine pan assemblies described above. Such portable environments may include a car, a recreation vehicle ("RV"), a boat, a ship, a camper, a bus, an airplane, and a moveable toilet shelter (i.e., a "Port-A-John" or "Johnny On The Spot").

[00126] It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.

Claims

We claim:

1. A latrine pan comprising a collection basin and a flapper,

the collection basin having an upper bowl portion tapering from an upper rim having an outer surface to an outlet extending through a wall of the collection basin at a lower portion of the collection basin,

the flapper comprising a counterbalance device and a coverplate disposed on opposite sides of a pivot, the counterbalance device comprising a plurality of counterweight am s;

the coverplate having an upper face adapted to cover the outlet of the collection basin when the upper face is engaged against the lower portion of the collection basin, the flapper being pivotally mounted against the collection basin such that the coverplate engages against the lower portion of the collection basin when a pivotal force attributable to the counterbalance device is substantially equal to or slightly greater than a pivotal force attributable the coverplate,

wherein a human waste quantity deposited in the latrine pan is hygienically and sustainably removed to a disposal pit with low or no water use.

2. The latrine pan of claim 1 , wherein the counterbalance device has two counterweight arms.

3. The latrine pan of claim 2, wherein the counterweight arms each have an arcuate shape.

4. The latrine pan of claim 2, wherein the two counterweight arms together form wishbone-shaped structure disposed at a distalmost end of the flapper.

5. The latrine pan of claim 1 , wherein the counterweight arms are disposed relative to the collection basin to permit the flapper to downwardly rotate about 80 degrees around the pivot without contacting the collection basin.

6. The latrine pan of claim 1 , wherein the counterweight arms are disposed relative to the collection basin to permit the flapper to downwardly rotate about 90 degrees around the pivot without contacting the collection basin.

7. The latrine pan of claim 1, wherein the counterweight arms are disposed relative to the collection basin to permit the flapper to downwardly rotate about 95 degrees around the pivot without contacting the collection basin.

8. The latrine pan of claim 1, wherein the counterbalance device comprises at least three arms.

9. The latrine pan of claim 1 , comprising a flange extending from the upper rim and around the perimeter of the upper bowl portion.

10. The latrine pan of claim 1, wherein the flapper is pivotally mounted to the exterior of the collection basin.

1 1. The latrine pan of claim 1 , wherein the pivot of the flapper is a pair of pins extending laterally away from an extension body of the flapper, the counterbalance device and coverplate being mounted on opposite ends of the flapper, and the pins engaging a pair of aligned holes on a pair of spaced brackets on the exterior of the collection basin.

12. The latrine pan of claim 1 , wherein the pivot of the flapper has at least one hole extending laterally through an extension body of the flapper, the counterbalance device and coverplate being mounted on opposite ends of the flapper, each hole engaging a pin extending from the exterior of the collection basin.

13. The latrine pan of claim 1 , wherein the pivot of the flapper is at least one hole extending laterally through an extension body of the flapper, the counterbalance device and coverplate being mounted on opposite ends of the flapper, each hole engaging a pin that also engages a pair of aligned holes on a pair of spaced brackets on the exterior of the collection basin.

14. The latrine pan of claim 1, further comprising a pull attached to and extending from the flapper on the counterweight side of the pivot, whereby the flapper can be pivoted about the pivot to displace the upper surface of the coverplate from the lower portion of the collection basin by exerting a force along the pull.

15. The latrine pan of claim 1, wherein the coverplate retains an amount of water sufficient to form a water seal to prevent passage of gases or insects through the lower portion of the collection basin.

16. The latrine pan of claim 15, wherein the amount of water is about 20 to about

50 ml.

17. The latrine pan of claim 15, wherein the gas is hydrogen sulfide or ammonia. 18. The latrine pan of claim 15, wherein the insects are flying insects.

19. The latrine pan of claim 15, wherein the amount of water is about 50 ml or less.

20. The latrine pan of claim 1, wherein the coverplate is shaped to defines a cup that cups the lower portion of the collection basin and covers the outlet when the coverplate is engaged against the lower portion of the collection basin.

21. The latrine pan of claim 1, wherein the collection basin is manufactured of a material selected from a polymer, a plastic, a composite, a metal, a concrete, a cement, a natural or synthetic stone, a composite, a wood, a fiberglass, a porcelain, a ceramic, gravel, and a clay.

22. The latrine pan of claim 1 , wherein the flapper is manufactured of a material selected from polymer, a plastic, a composite, a metal, a concrete, a cement, a natural or synthetic stone, a composite, a wood, a fiberglass, a porcelain, a ceramic, gravel, and a clay.

23. The latrine pan of claim 1 wherein the upper face of the coverplate is coated with an adherence-reducing material.

24. A latrine pan assembly comprising the latrine pan of any of claims 1 -23 attached to a stool frame.

25. The assembly of claim 24, wherein the stool frame maintain a top surface of the latrine pan at about 5 inches to about 20 inches, or about 8 inches to about 25 inches above a standing surface.

26. The assembly of claim 24, wherein the stool frame comprises a hollow cylinder having an upper edge to which the latrine pan is mounted.

27. The assembly of claim 26, wherein the upper edge of the stool frame further comprises a flange extending inwardly towards the center of the hollow cylinder to which the latrine pan is mounted.

28. The assembly of claim 26, wherein the sidewall of the hollow cylinder is continuous.

29. The assembly of claim 26, wherein the sidewall of the hollow cylinder is discontinuous.

30. The assembly of claim 26, wherein the pull extends through an orifice extending through the sidewall of the hollow cylinder.

31. The assembly of claim 30, wherein the pull is attached to a handle that is incapable of passing through the orifice.

32. The assembly of any of claims 24-31 further comprising a water dispensing vessel.

33. The assembly of claim 32, wherein the water dispensing vessel is selected from a bucket, a pail, a spout-bearing vessel, a hose, and an expandable bladder.

34. The assembly of claim 32, wherein the water dispensing vessel is a squirt bottle.

35. The assembly of any of claims 24-34, further comprising written materials.

36. The assembly of claim 35, wherein the written materials comprise a communication device that provides at least one of (a) instructions for assembly of the latrine pan, (b) instructions for installation of the latrine pan, (c) instructions for use or installation of the pan assembly, and (d) instructions for maintenance of the latrine pan assembly.

37. The latrine pan assembly of claim 36, wherein the communication device comprises text, a drawing, and a cartoon.

38. A latrine pan assembly comprising the latrine pan of any of claims 1 -23 attached to a platform having a top surface and a bottom surface.

39. The latrine pan assembly of claim 38, wherein the top surface includes at least one anti-slip device.

40. The latrine pan assembly of claim 38, wherein the bottom surface includes an lattice overlay.

42. The latrine pan assembly of any of claims 38-40, further comprising a water dispensing vessel.

43. The assembly of claim 42, wherein the water dispensing vessel is selected from a bucket, a pail, a spout-bearing vessel, a hose, and an expandable bladder.

44. The assembly of claim 42, wherein the water dispensing vessel is a squirt bottle.

45. The assembly of claim 42, further comprising written materials.

46. The assembly of claim 45, wherein the written materials comprise a communication device that provides at least one of (a) instructions for assembly of the latrine pan, (b) instructions for installation of the latrine pan, (c) instructions for use or installation of the pan assembly, and (d) instructions for maintenance of the latrine pan assembly.

47. The latrine pan assembly of claim 36, wherein the communication device comprises text, a drawing, and a cartoon.

48. A method of reducing the amount of water per use of a pit latrine, the method comprising installing over a latrine pit the latrine pan of any of claims 1-23, wherein the average amount of water per use required to remove an average human waste quantity from the latrine pan is about 0 ml to about 150 ml.

49. The method of claim 48, wherein the average amount of water per use is about 100 ml.

50. A method of reducing the amount of water per use of a latrine, the method comprising installing over a latrine pit the latrine assembly of any of claims 24-37, wherein the average amount of water per use required to remove an average human waste quantity from the latrine pan is about 0 ml to about 150 ml.

51. The method of claim 50, wherein the average amount of water per use is about 100 ml.

52. A method of installing a latrine comprising fitting the latrine pan of any of claims 1-23 or the latrine pan assembly of any of claims 24-37 in fluid communication with a leach pit.

53. The method of claim 52, wherein the latrine pan or the latrine pan assembly is fitted into a mud floored area.

54. A latrine comprising a leach pit in fluid communication with the latrine pan of any of claims 1-23 or the latrine pan assembly of any of claims 24-47.

55. The latrine of claim 54, sited in a public sanitation facility.

56. The latrine pan of claim 54, sited in a family residence.

57. A method of sustainably and hygienically separating human excreta from human contact with use of negligible amount of water comprising:

providing a latrine of any of claims 54-56;

delivering to the coverplate of the latrine pan a waste amount of a user, wherein the waste amount contacts an upper face of the coverplate and the pivotal force exerted by the waste amount causes the flapper to rotate downwardly about the pivot about 80 to about 90 degrees, such that the waste amount is released from the coverplate and descends into the latrine pit and

wherein upon release of the waste amount form the upper face of the coverplate, the coverplate re-engages against the lower portion of the collection basin.

58. The method of claim 57 wherein an amount of water selected from about 50 ml, about 100 ml and about 150 ml is applied to the coverplate to aid the rotation of the flapper and, upon re-engagement of the coverplate, a liquid seal is formed between the upper surface of the coverplate and the lower portion of the collection basin.

59. The method of claim 58, wherein the water is applied by use of a squirt bottle.

60. A waste disposal system for use in a portable environment, the system comprising a waste disposal conduit in fluid communication with the latrine pan of any of claims 1-23 or the latrine pan assembly of any of claims 24-47.

61. The waste disposal system of claim 50, wherein the portable environment is selected from a car, a recreation vehicle ("RV"), a boat, a ship, a camper, a bus, an airplane, and a moveable toilet shelter.