1) Description of the waterless toilet

• The waterless toilet consists of a toilet station for receiving faecal matter and diverting urine (the pedestal). This includes a kiddie seat.
• A waste collection station for collecting drying faecal matter, which contains a removable bag for final disposal of the waste (the sump)
• An endless conduit which is a drying passage (the housing).
• A conveyor inside the housing use to transport the faecal matter, consisting of continuous abutting scraper elements (scraper rings)
• A ventilation system for moving ambient air through the pedestal, into the housing and through the sump. This is powered by a wind turbine.

This housing extends underneath the pedestal and is used for transporting the faecal matter to the sump. Part of the housing is exposed to solar radiation for heating the faecal matter. This is to help desiccate the faecal matter and expose the pathogens to a high enough temperature whereby they are rendered harmless.

The faecal matter is deposited directly into the scraper rings, which are then moved round by means of a shuttle. The shuttle is attached to a lever, which is pulled by the user after each use. After each use the faecal matter is transported around the housing until it reaches the sump, where it falls through a hole in the housing into a bag that has been inserted into the sump.

The Solarsan waterless toilet may be located indoors or outdoors in an outhouse. In the former situation we use an oblong housing with round scraper rings, in order to minimize the space that the housing takes. In the latter, we use a round housing with ‘square' (parallel arcs) scraper rings. In both cases the housing, other than the section that is immediately beneath the pedestal, is located outside of the building for exposure to solar radiation.

This waterless toilet involves a secondary and final step in disposal of the waste-

• The urine can be diverted to a soak away or (preferably) collected and used as a fertiliser. If the latter is the case, it should be diluted one part urine to three parts water and then used in the normal way.
• The faeces can be composted, buried or burnt. The latter disposal method is our preferred method and made possible through the heating and drying process that takes place in our waterless toilet. It is preferred because it is easy, no transport of the waste is necessary, no outside agency is needed and the resultant ash is completely safe.

We are willing to enter into a service contract that would include secondary disposal of the waste, if it was felt that community might be resistant to final disposal.

The only public health risk involved in our waterless toilet comes from the handling of the faeces during its secondary disposal. Care must be taken to protect the handler from exposure to those pathogens that may be remaining in the faeces. This care need only consist of standard personal hygiene, i.e. hand washing. Because the faeces is both heated, stored and dehydrated the pathogen count is much lower than the handling of partly fresh faeces that takes place in some other waterless toilets.

As the waterless toilet is sealed there can be no leakage of pathogens from the faeces into the ground water. A combination of dehydration and airflow keeps flies and smell away. The urine is diverted away from the faeces either into a soak away or a container for later use as a fertiliser. This poses little to no risk.

At present our waterless toilet needs to be level to achieve optimum functionality. If it is an outhouse this means that you need a level area of 2m x 3m. If you are using the indoor version, the housing extends 2m out of the back of the house. This fits in into most footprints for newly built houses at the present time.

Not only does the housing need to be flat, but it must be exposed to the sun for at least four hours a day. Because our waterless toilet is dependant on both solar radiation and wind, especially the former, we do not know how it would perform in colder climates (it has not been tested in such regions). It has been designed so that one unit is suitable for a family of 8. If it is continuously overloaded the faeces will not dry satisfactorily. We have experienced an installation where 40 people have happily used the waterless toilet for a period of 6 months. The unit functioned satisfactorily, but when it was time to empty the sump, the faeces had to buried. If the waterless toilet is occasionally overloaded, due to a party, funeral etc., the drying continues in the sump.

The waterless toilet functions better under conditions of steady use. If it is not going to be used for some time, the faeces remaining in the housing must be conveyed to the sump, to mitigate any possibility of the faeces drying out and ‘gluing' the scraper rings to the housing.

Any anal cleansing paper can be used, but the waterless toilet can block if it is used as a rubbish pit, e.g tin cans etc.. Most objects that are likely to block the system, will block it at the base of the pedestal and then can be easily removed.

The waterless toilet is lightweight, yet robust and made from UV treated black LDPE1. It weighs less than 40 kilos and so does not need any foundations. Excavation is minimal (the only hole needed is 1m x 60cm x 70 cm deep) and as such is ideal for areas where excavation is difficult.

2) Visual Inspection

A waterless toilet has been taken to Durban metro and inspected by John Harris. The waterless toilets are easily transportable and the exercise can easily be repeated.

There have been installations in Gauteng and Mpumalanga . So far, about 800 units have been installed in those two provinces. The oldest units are over two years old. Some of them were prototypes and as such failed. Those that were further down the development line are still functioning.

In KZN, we have just started our marketing efforts. There have been only about a dozen installations, so far, but this small number has enabled us to monitor and improve the product for durability and robustness. Feedback from the little that we have done in KZN so far has been good. The most common comments have been a lack of smell and the fact that each time you are using an unsoiled toilet.

3) Scientific details and description of operation

This is beyond my ability to supply.

We have had a sample tested by CSIR, the results of which are included below –

We have had the waterless toilet tested by SABS for durability. The result is also included –

4) Servicing Requirements and User Operation

Please see following poster for operating instructions. This poster is produced in Zulu as well. A laminated A4 copy is supplied with each waterless toilet.

There should be no maintenance required by the user other than the emptying of the sump bag and disposal of the dried faeces. The sump bag should be inspected after four months, but will probably need emptying only after every six months – depending on usage. The urine container will need to be replaced when full. If a soak away is used, there will be no maintenance for the urine.

This emptying of the sump bag can be undertaken by a third party, the municipality, ourselves or a local entrepreneur or a combination of all three. The cost that we would charge for this service would depend on the number of units sited within a particular settlement. No tools are needed to perform this operation.

One of the advantages of our waterless toilet, as it is not a composting system is that no ash, lime grit of other special additives are needed. Any anal cleansing material (other than water) can be used and disposed of into the waterless toilet. It will then be burnt or buried with the faeces at six monthly intervals.

The only mechanical working parts are the cam and shuttle. These are readily available (we will always have them in storage) and can be inserted by removing the pedestal and attaching. A rivet gun and spanner are necessary for this procedure. The only other moving parts (though not working) are the scraper rings. If for some reason one of them breaks – an event that has not occurred to date – they can be replaced by removal of the pedestal, removal of the broken scraper and reattachment of a new scraper. Only a spanner is needed for this operation.

5) Practicality of Use

The waterless toilet is supplied with a specially designed seat. This consists of the usual bottom part, but the lid has an insert cut out in order for children not to defecate into the urine diversion pan and vice versa. There is no covering lid on the seat, so that there can be a continual flow of fresh air to facilitate the drying of the faeces and to ensure that there is no smell in the toilet. This is also helped by our whirlybird which operates on a convection basis and is thus effective when there is no breeze.

The bowl can be cleaned in the normal way with a toilet brush, some disinfectant, but with little water. A small amount of water entering the waterless toilet won't damage the system and will evaporate in due course.

There are no operating costs, but it is important that the handle is pulled regularly. If there are problems with the conveyor waterless toilet, the sooner the problem is addressed, the easier it is to rectify. The vast majority of problems that we have had are when the waterless toilet becomes overloaded and the scraper rings stick. It is sometimes necessary then to shunt the scraper rings round with a stick or by hand until they are freed.

The other problem (though much rarer) is that the shuttle mechanism can flip over on itself. In order to easily solve both the above problems, we have recently moulded two removable inspection panels into the housing; one above the shuttle and one above the sump. The panel lids can be easily removed and re-attached with a screwdriver.

6) Robustness of Materials

See above for the SABS test results. We asked for 50,000 cycles to be tested, because it approximates to twenty years of use for a family of six. There will obviously be more strain on the waterless toilet when it is use, but SABS refused to do 50,000 bowel movements for us.

We have used materials with the high levels of corrosion caused by faeces and conditions on the coast, in mind.

The following is list of the materials used; all the plastic components are UV stabilised

Housing Rotor moulded in black LDPE1

Sump and sump lid Rotor moulded in black LDPE1

Pedestal Rotor moulded in various colours in LDPE1

UDS Rotor moulded in various colours in LDPE1

All rotor moulded items are at least 5mm thick

Scrapper rings injection moulded in black ABS

Whirly bird injection moulded in black ABS, plus s/s spindle and bearings

Vent pipe storm water black 110ml pipes (not UV stabilised)

Shuttle 304 s/s x 1.5 mm

Cable s/s

Rivets monol

Washers s/s

Cam and handle galvanised mild steel

Seat supawood, alloy hinges

Nuts and bolts s/s

Sump bag 40% shade cloth

Sump bag frame galvinised mild steel

Sump lid rod galvinised mild steel

Vent bracket galvinised mild steel

UDS and urinal pipes 20 ml hose pipe, with s/s hose clips.

7) Construction/Installation Specification and Requirements

Below are the installation instructions, which are also available in Zulu.

Installation instructions for Solarsan Round Waterless Toilet

 Tools needed – medium flat screwdriver, silicon and silicon gun, bag of ready mixed concrete, pop rivet gun, drill with a 5mm drill bit, a 13 mm spanner and spirit level. Everything else is supplied

1. Select a suitable site to install the toilet, preferably in a corner 2m from house boundary and where the housing ring is exposed to the sun.

   

    

2. Dig a hole 1m x 60cm x 70 cm deep. Place sump into the hole and position the large ring over the sump. Using a spirit level, ensure that the ring is level. Remove the ring and fit the foam sealing strip around the larger hole of the sump. Make sure it sticks well. Inject silicon sealant over the foam strip. Replace the ring and bolt it to the sump with 4 (four) 50mm x 8mm stainless steel bolts and washers

   

    

    

   

3. Place pedestal onto ring, sliding the shuttle into the ring. Secure with 4 (four) 20mm x 8mm bolts and washers. Take 70 cm of hosepipe and attach urinal outlet of pedestal. The hosepipe must exit through the back of the pedestal. Secure the hosepipe with a hose clamp.

   

    

4. Now erect your hut over the pedestal. The instructions will depend upon which hut you have chosen. After the hut has been erected, check the level of the large ring again with your spirit level. Once you are happy that is level, lay a bag of concrete around the pedestal to secure the unit

    

   

    

5. Take a 1.5m hosepipe and connect to the outlet of the urinal , securing with a hose clamp. Secure your urinal to the wall of the hut 70cm from the floor with two pop rivets in the urinal and two washers on the outside of the hut. Using the red tee-piece join the hosepipes from the urinal and the pedestal onto your remaining hosepipe. This hosepipe goes into the hole next to the sump, into which must be placed stones or general builders' rubble for your urine soak away. Secure the hosepipe to the hut wall with a ‘U' bracket. Make sure that there are no loops in the hose to trap the urine. Cover up soak away and level to 8cm from the top of the large ring.

    

   

6. Fit the whirly bird to the black vent pipe using three pop rivets. Put the vent pipe over the sump vent outlet. Secure the pipe to the hut using the vent pipe bracket and rivet the bracket to the hut with the washers on the inside of the hut.

    

   

7. Slide the sump bag and frame into the sump. Push on the sump lid , securing with lid pin. Clean installation and test toilet by pulling the handle 30 times.

As you can see from the above, installation is very simple and, after a bit of practice takes than less than one day's labour. This does not include the superstructure.

Our waterless toilet is suitable for all geological and environmental conditions, other than in the shade, as previously stated. It is especially useful in ecologically sensitive areas, areas with a high water table or areas where excavation is difficult.