Field of the invention:

The present invention generally relates to a facility for treating toilet waste safely and completely within a limited space and in areas where it is impossible to use pit latrines or septic tanks because of the nature of the ground conditions. Background of the invention:

Providing sanitation in difficult environments where there is a risk of flooding, or a high water table, or hard rocky ground, or heavy impermeable soils, is a challenge that has not yet been met. Conventional sanitation solutions such as pit latrines and septic tanks are not suitable for a number of reasons. In the case of hard rocky ground pit latrines cannot be used because holes cannot be dug and septic tanks, if sited above ground, are apt to leak and cause problems with smells and flies, and are thus hazardous to health. In the case of flood-prone or high water table areas, latrines will flood and waste will be spilled, risking the spread of disease. Septic tanks may also overflow. In areas of heavy impermeable soils drainage will be slow and effluent may back up causing blockages and failure of the system.

Vermifilters have previously been reported to be a superior form of sanitation to both septic tanks and pit latrines. Earthworms are well known to promote digestion of organic waste, which results in the production of vermicompost. In Vermifilters, this behavior is combined with filtration to digest faecal matter and treat the resulting liquid effluent on-site, i.e. adjacent to the home. The worms need only air, water and food to form a sustainable population in the vermifilter. The basic concept of a wet vermifilter for on-site sanitation has been described and proven (Furlong et al 2014a). It comprises a tank containing a vermifilter made up of two main components: a bedding layer at the top which provides the correct environment for the worms and acts as a primary filter, and a drainage layer underneath which further treats the effluent. Based on this, simple designs were developed which have been constructed from locally available materials such as bricks and mortar for field testing. The results of the field testing showed promise (Furlong et al 2014 b).

Prior to the work described by Furlong et al a small number of patents and patent applications disclosed the use of filtration in combination with worms and other organisms for the treatment of faecal waste (WO 0190007, WO 9507872, US 5919366, WO 9406734, US 2005/0006304). The method in most cases is referred to as biolytic filtration. In this method, the filtration matrix employed is usually compost ("humus") which may be supported by structural elements and arranged in a number of configurations. US patent publication no. 2005/0006304 disclosed separate treatment of urine and faeces, wherein the liquid effluent is treated by passing through combinations of coarse and fine trickle bed media. Some of these patents also describe the use of pumps to recirculate effluent. An Indian patent application number 3131/MUM/2015 describes improved vermifilter designs and materials suitable for large scale production and distribution.

None of the designs of vermifilter published or patented previously have utility for sanitation in difficult environments such as hard rock, high water table, flood- prone areas, or soil with low permeability. These are however the conditions under which many of the people that need sanitation live. The Vermifilters previously reported are mainly designed such that the effluent will drain away; either directly by permeation into the soil or via a surface drain. This is not practical or safe in the areas with difficult environments. In terms of practicality, surface drains are not usually present and the soil is not suitable for direct infiltration, or may be completely impermeable in the case of hard rock. In terms of safety, there is a risk of bacterial pathogens from the effluent contaminating the surface or ground water and spreading disease as a result. Furthermore, previous designs have usually involved the vermifilter unit being placed in a hole in the ground adjacent to the toilet, which is clearly impossible in hard rock areas. Further in flood-prone or high water table areas it is important that all elements of the system are kept above the water level as far as possible to prevent drowning of the earthworms by ingress of water.

Thus the main deficiencies in the prior art are that they do not provide a solution to overcome the problems of drainage in these situations or do not provide a means of dealing with the effluent when drainage is difficult, slow, or impossible.

Hence, there exists a need to provide a complete sanitation solution for difficult environments that overcomes the above mentioned drawbacks of the prior art.

Objects of the invention:

An object of the present invention is to provide a complete sanitation solution for difficult environments such as hard rock and high -water table areas.

Another object of the present invention is to reduce the risk of environmental pollution or disease.

Yet another object of the present invention is to provide a quick and easy to install sanitation solution. Summary of the invention:

Accordingly, the present invention provides a toilet system offering safe and complete waste treatment in a difficult terrain. The toilet system comprises a toilet facility, a platform, a digester and a secondary drainage bed that are connected together and configured based on the nature of ground conditions. The toilet facility includes housing with a pour-flush / flush toilet. The platform is raised solid platform/a slab formed from a rigid and strong material required to support weight of a user. The toilet facility is inserted into the platform and is connected to water seals with a number of pipings underneath the platform. The digester consists of a tank, tray(s) or other suitable form of containment for housing a primary vermifilter that collects effluent from the toilet facility therein. The primary vermifilter includes an active zone, a worm bed and a filtration bed. The active zone facilitates digestion of the effluent by using worm species such as Eisenia fetida and Eisenia andreii. The worm bed provides a habitat for the worm species in the form of biomedia. The filtration bed includes layers of drainage media for filtering out the effluent therefrom. The secondary drainage bed is connected to the primary vermifilter externally so that effluent flows from the toilet facility to the primary vermifilter and into the secondary drainage bed. In case of hard rock terrain, the primary vermifilter is housed beneath the toilet facility and the primary vermifilter consists of an optional free board to allow space for pipework. In case of terrain with heavy soils and high water tables, the primary vermifilter is housed externally above ground in the digester adjacent to the toilet facility and is connected to the secondary drainage bed

Brief description of the drawings:

The objectives and advantages of the present invention will become apparent from the following description read in accordance with the accompanying drawings wherein, Figure 1 shows a fully closed toilet system configuration suitable for hard rock areas with various views including A) Front Elevation View, B) Sectional Elevation View and C) Plan View, in accordance with the present invention;

Figure 2 shows configurations of the toilet system for heavy soils or high water tables, in accordance with the present invention; and Figure 3 shows configurations of the toilet system for heavy soils, in accordance with the present invention.

Detailed description of the invention:

The foregoing objects of the invention are accomplished and the problems and shortcomings associated with the prior art techniques and approaches are overcome by the present invention as described below in the preferred embodiment.

The present invention provides a toilet system offering safe and complete waste treatment in difficult terrain such as hard rock and high -water table areas. The toilet system configurations of the present invention are quick and easy to install sanitation solutions that reduce the risk of environmental pollution or disease.

The present invention is illustrated with reference to the accompanying drawing, throughout which reference numbers indicate corresponding parts in the various figures. These reference numbers are shown in bracket in the following description.

Referring to figures 1 - 3, a toilet system (100) offering safe and complete waste treatment in a difficult terrain is described in accordance with the present invention. The toilet system (100) is a complete system comprising a toilet facility/structure (20), a platform (40) and a digester (80) having a primary vermifilter (60) and a secondary drainage bed (90). The above mentioned parts are connected together so that effluent flows from the toilet facility/structure (20) to the primary vermifilter (60) and into the secondary drainage bed (90). The above mentioned parts can be configured in different ways, depending on the nature of the ground conditions, which can range from heavy soils (e.g. clay shown in figure 3) through high-water table (shown in figure 2) through to hard rock (shown in figure 1). Figure 1 describes a fully closed toilet system (100) suitable for hard rock areas.

The external toilet facility/structure (20) (typically of the squat type) is formed from durable, readily available and transportable materials at the site including but not limited to concrete, brick, wood, metal sheets, sandwich panels, lightweight concrete and recycled compressed plastic boards. In an embodiment, the toilet facility/structure (20) can be made from ready to assemble pre-cast panels as per an embodiment of the present invention. The toilet facility/structure (20) will be entered by ascending a small number of steps, to provide height for drainage of effluent from the system and to prevent ingress of flood water. The external toilet structure (20) includes housing (15) and a pour-flush / flush toilet (10). The toilet structure (20) is inserted into the platform (40). The platform (40) is a raised solid platform or a slab formed from a rigid, strong material including but not limited to plastic, concrete. The platform is required to support the weight of the user. The platform may include ports or flaps (not shown) configured therein. Underneath the platform, the toilet facility (20) is connected to water seals (not shown) and includes a number of pipings (not numbered) and a slope (50) connected thereto through which the effluent passes into the digester (80).

The digester (80) consists of a tank or tray(s) or other suitable form of containment which house the primary vermifilter (60) and is connected to the secondary drainage bed (90) external to the primary vermifilter (60). The tank or tray(s) of the digester (80) may be made from lighter weight materials such as plastic or fiberglass or any other suitable material. In an embodiment, the digester (80) can be made of an adequate surface area/size depending on the number of users. For example, around 0.1 square meters per person can be considered for deciding the surface area of the digester. The tank or tray(s) of the digester (80) can be made in different shapes selected from any one of cylindrical and rectangular.

The primary vermifilter (60) inside the digester (80) is accessed either through a lid (not shown) if it is external to the toilet facility or through the ports or flaps in the platform (40) and the rear of the toilet structure (20), if it is placed beneath, to allow inspection and maintenance. The primary vermifilter (60) consists of an optional free board (in case of hard rock areas), to allow space for pipework, an active zone (52), where digestion is taking place, biomedia which forms a worm bed (54) and a filtration bed (56). Within the active zone (52), worm species such as Eisenia fetida and Eisenia andreii capable of composting faecal waste break down toilet waste as it enters. The worm bed (54) is adapted to provide a habitat for worm species in the form of biomedia. The worm bed (54) is made from a material including but not limited to coir, compost, word chip, or mixtures thereof or any other suitable material known to provide a good environment for worm behavior and health and propagation. The filtration bed (56) consists of one or more layers of drainage media such as gravel, pebbles, boulders, aggregate, stones, sand, cement coated- polymeric foam, rubber, recycled tyres, coir, "bioballs", wrapping materials used in field drains and different types and configurations of plastic, glass, light expanded clay aggregates/balls or any other suitable materials. The filtration bed (56) properties can also be provided by a suitable arrangement of plastic plates, mesh or blocks to create the desired void dimensions and capacity. In case of terrain with heavy soils or high water tables, the primary vermifilter (60) is housed externally above ground in the digester (80) adjacent to the toilet facility (20) (as shown in figures 2 and 3). In the case of hard rock terrain, the primary vermifilter (60) is housed beneath the toilet facility (20).

The secondary drainage bed (90) or drainage channel is formed at the base or is provided separately in the form of offset drainage bed or soak away or soak pit from the primary vermifilter (60) to ensure that the toilet system (100) drains freely. Specifically, the secondary drainage bed (90) is a shallow layer formed of gravel, pebbles, boulders, aggregate, stones, sand, cement coated- polymeric foam, rubber, recycled tyres, coir, "bioballs", wrapping materials used in field drains and different types and configurations of plastic, glass or light expanded clay aggregates/balls or any other suitable materials. The filter bed properties can also be provided by a suitable arrangement of plastic plates, mesh or blocks to create the desired void dimensions and capacity. The digester (80) is attached to secondary drainage bed (90) selected from any one of a planted bed, a soak pit and a soak away system. In a first embodiment, in case of terrain such as hard rock areas, the digester (80) is connected to the secondary drainage bed (90) in the form of the planted bed, wherein water is finally lost through evaporation and the digested effluent is further treated by absorption of nutrients by the plants as shown in figure 1. In the most extreme case, where there is no possibility of any drainage or infiltration into the surrounding environment, e.g. on hard rock, a completely closed system of the toilet structure (20), the primary vermifilter (60) and the secondary drainage bed (90)- has been designed from which effluent cannot escape and contaminate surfaces or ground water. It is more compact than previous vermifilters and needs much less depth for installation so can be installed in any situation or terrain, even in hard rock areas. The toilet facility (20) has a raised platform (40) with a shallow vermifilter (60) underneath. A level site is formed for the toilet structure and a shallow trench is excavated around its perimeter to house the drainage bed. The effluent passes out through a number of drainage holes (81), on the three sides of the toilet away from the steps, thereafter drains into the shallow drainage bed/ channel around the toilet, wherein the drainage channel is planted with plants to take up water through evaporation of water and the residual nutrients are used to support growth of plants for decoration thereby enhancing the appearance of the structure. In a second embodiment, in case of terrain with heavy soil or high water tables, the toilet structure (20) is raised, and the primary vermifilter (60) is housed above ground in the digester (80) alongside from where the effluent drains into the secondary drainage bed (90) that comprises a soak pit (84), wherein an outlet pipe (82) delivers the digested effluent from the digester (80) to the soak pit (84) such that the effluent drains into the shallow soak pit (84) containing any suitable drainage media as shown in figure 2.

In a third embodiment, in case of terrain with heavy soil, the secondary drainage bed (90) comprises a soak away system (88), wherein a trench is used to house the secondary drainage bed (90) and a perforated pipe (86) delivers the digested effluent from the digester (80) to the soak away system (88) as shown in figure 3. In both the configurations of figures 2 and 3, water slowly seeps through the drainage media into the surrounding soil.

Thus, the alternative configurations in figures 2 and 3 again have the toilet facility (20) raised but the primary vermifilter (60) is housed above ground in a suitable tank alongside, from where the effluent can drain either into a soak pit, trench, or plant bed depending on the ground conditions and capacity for infiltration. This would be particularly suitable for areas where the soil layer is shallow or infiltration rates are low.

In an exemplary embodiment, the toilet facility (20) with the digester (80) and secondary filter bed (90) using the design in Figure 3 was installed in each of two homes for use by family members, and the performance was monitored over six months. The dimensions of the digester (80) and the secondary filter bed (90) are shown in Table 1 below:

Table 1 : Details of the toilet system (100) for household use:

High-density

Material (Tank) -- -- polyethylene (HDPE)

Diameter/width Meters 1.03 0.9

Square

Surface Area 0.83 0.81

Meters

Depth Meters 0.73 0.15

Volume Litres 607.95 121.50

Depth of

Meters 0.25 0.15 drainage layer

Percenta

Void Capacity 40% 50%

ge (%)

Void Capacity Litres 83.28 60.75

In this example, coir and aggregate formed the drainage bed in the digester, and aggregate and boulders were used in the leach field. Both of these demonstrator models were monitored weekly for 2 months and monthly afterwards. Samples were taken from the outlet of the above ground digester. These were compared with influent values, collected freshly, to assess effluent quality. To check faecal removal visual observation was used. To check worm health visual observation was used to assess vermicompost production. Any evidence of smells was also noted.

The key results from these trials for effluent quality over 6 months are shown below in Table 2: Table 2 - Effluent quality from Above Ground Digester: Time from

COD % BOD % Total Solids Start (

reduction reduction Reduction

Months)

1 70 88 75

2 85 92 95

3 88 93 93

4 92 82 93

5 86 90 92

6 90 89 94

Bearing in mind that the samples were taken from the outlet of the digester, and that in normal use the effluent would still have to pass through a further drainage bed, the results show that the effluent quality is good and comparable to the existing standard model.

Visual observations showed that there was no accumulation of faecal matter inside the digester, confirming that the worm population was active and functioning as expected. This was further borne out by signs of vermicompost production. No smells were detected around the digester.

Advantages of the invention:

1. The toilet system (100) is made with a range of options allowing it to be installed anywhere, even in difficult environments where it is impossible or unsafe to dig a pit.

2. The toilet system (100) greatly reduces the risk of contamination, environmental pollution or disease.

3. The toilet system (100) is quick and easy to construct.

4. The key advance is to be able to house the primary vermifilter (60) above ground and deal with the drainage of effluent in a number of different ways depending on the nature of the terrain. The foregoing objects of the invention are accomplished and the problems and shortcomings associated with prior art techniques and approaches are overcome by the present invention described in the present embodiment. Detailed descriptions of the preferred embodiment are provided herein; however, it is to be understood that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed system, structure, or matter. The embodiments of the invention as described above and the methods disclosed herein will suggest further modification and alterations to those skilled in the art. Such further modifications and alterations may be made without departing from the scope of the invention.