The simplest and traditionally known method of sewage feacal waste disposal is the squatting method whereby feaces are disposed anywhere in the open environment. This is rather a primitive method because the normal assumption is that the feaces will be baked by the sun leading into the death of disease causing microbes. Hence in circumstances where the flush toilet cannot be affordable, the need to construct and maintain toilets arises. We are capable of constructing and maintaining various types of pit latrines;the simple pit latrine and the VIP (Ventilation Improved Pit) Latrine.

Pit Latrine Construction

We carry out the following processes in the construction of pit latrines;
 

1. We advise on the site of a latrine and this should preferably be in the backyard of the house and away from an alley in the village. It should not be nearer than 6 m or farther than 50 m from the house. The direction of the wind should be away from the main house. If there is a well in the compound, the latrine should be located as far away from it as possible on the downhill side to avoid possible seeping and contamination of groundwater. The faecal microorganisms may migrate from the pit through the soil, however, the degree that this happens varies with the type of soil, moisture levels and other environmental factors. It is, therefore, difficult to estimate the necessary distance between a pit and a water source, but 30–50 m is the recommended minimum, with an absolute minimum of 15 m. However our bio-digester reduces the risk of ground water contamination immensely.
2. The size of the pit depends on the number of people using it and the design period, i.e. the length of time before it is full. typically, the pit should be at least 3 m deep for a family of five for a design period of three to five years. The diameter should be at least 1 m; up to 1.2 m diameter will make it easier to dig but if it exceeds 1.5 m there is an increased risk of collapse, especially in sandy soils. 
3. We also consider the geology, soil type and topography (the slope of the land) when considering sanitation technologies. In flood-prone areas, it is advisable to raise the mound of the latrine and prepare diversion ditches around it. When the soil condition is rocky and it is impossible to dig a deep pit, the depth of the pit can be extended by building upwards with concrete rings or blocks. However, care must be taken to ensure the structure remains watertight. The level of the water table must also be taken into consideration. The pit must be entirely above the water table at all times of the year. If the water table is near the surface of the ground, the waste in the pit may contaminate the groundwater.
4. Lining the pit prevents it from collapsing and provides support to the superstructure. The pit lining material can be brick, rot-resistant timber, concrete, stones, or mortar plastered on to the soil. If the soil is stable (i.e. no sand or gravel deposits or loose organic materials), the whole pit need not be lined. The bottom of the pit should remain unlined to allow the percolation of liquids out of the pit.
5. The superstructure should be built using locally available materials. These may include a masonry wall made of cement blocks, bricks, or stone with cement or mud bindings; or a wooden structure covered with timber, bamboo, grass/thatch, sticks, leaves of banana, or canvas made of sacks. However, the type of superstructure depends on several factors such as a institutional or household’s financial capacity, the availability of construction material locally, local customs and traditions, and the availability of skilled artisans.
6. Ventilated improved pit (VIP) latrine; The VIP latrine is an improvement over the simple dry pit latrine. The distinctive feature that gives the VIP latrine its name is the vent pipe installed into the pit, which is used to exhaust the foul odour from the pit and control flies.

 
Diagram of VIP latrine

The principle is that a continuous flow of air comes in through the superstructure and enters the pit through the hole. This cold air will go down into the pit displacing (pushing up) the hot smelly air upward through the vent pipe. The other advantage of the vent is controlling flies. Newly-emerging adult flies will try to escape through the vent pipe because the pipe allows sunlight to enter into the pit and flies are photopositive (meaning they move towards light) by nature. A mesh screen tied at the top of the vent pipe will prevent flies from escaping to the outside of the latrine.

VIP latrines can have a single pit or double pit. They share the advantages of simple pit latrines with slabs described above but they also have unique advantages that improve on the limitations, namely, that flies and odors are significantly reduced. It should be noted, however, that the health risks from flies are not completely removed by ventilation.