Low Cost Home Toilets to Prevent Open Defecation

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Defecation in open is widely prevalent in poorer parts of the world. It leads to inconvenience, torture of making their way to a distant field for sick and aged,  pollution of water bodies, several health problems and security issues particularly for women. There have been cases of women venturing out alone in the dark to ease themselves that have been way laid by a gang, raped and even murdered in the worst of cases. Presently an active program is underway in India led by the Narendra Modi Government to eradicate this practice through the building of squat flush toilets at homes across rural India.

The government offers financial help for the purpose. However in talking to villagers, this author discovered that villagers are spending much more than the assistance provided and this is slowing down the program. Huge expenditure is being incurred because of lack of knowledge and greed of contractors and masons who construct these toilets. This note is written with an intention to provide a low cost solution.

The largest part of the expenditure was being incurred by villagers in construction of septic tanks. Many were constructing tanks that were far too huge, in fact sufficient for an entire primary school rather than just a home. The large septic tanks required masonry work on sides to prevent the pits from collapsing and an expensive cover that added to costs that ran into tens of thousands of rupees for some.

This note describes a septic tank that is easily constructed within a day at home at a cost of approximately six hundred rupees only. It is an improved version of the septic drain described in an earlier note of this blog. It is simple to construct and does not require a mason. Any adult family member may construct it within a day. Because of its size and depth there is no danger of a child falling in to the pit and dying in case it collapses and also of any adult that might die in a large pit if they enter for cleaning. Exposure to methane gas in septic pits leads to swift death and many such cases are reported in media from time to time.

The Improved Septic drain:

The improved septic drain is a pit of length six feet that is 2 feet and 3 inches deep with a width of 1 foot and 3 inches covered by three stone or concrete slabs of size 2 feet by 2 feet. This size is sufficient for a family of six members not requiring cleaning more than once a year. The layout of the toilet of size 4’ x 4’ and the pit is shown in the figure above.

Materials required

15 kg Cement

15 bricks

3 square stone or concrete slabs of size 2’ x 2’

A cost of 150 rupees per stone slab has been assumed here (the current cost of Kota Stone slabs of size 2’ x 2’ and 1 inch thick ) leading to expenditure of 450 rupees. The total cost of the rest of listed materials would be under six hundred rupees. No other materials are required except a third of a bucket of sand if available; otherwise soil may be used to prepare the mortar for jointing.

Steps of Construction

Steps of construction are summarized in the figure above. This note provides further explanation

Step 1

At a distance of about two feet behind the toilet, wet the ground and mark out a rectangular area of size 2’ by 6’ feet with a sharp object. A long straight edge and some care are required here to try and ensure a perfect rectangle. Measure the diagonals to see they are equal. An inverted bed placed on ground can be used as a guide.

Next scrape out the soil from this rectangular area to a depth of six inches. Ensure sides are neat and vertical. In case they break a wet mud plaster may be used to repair and straighten them.

Step 2

Wet the ground and in the central portion of this scraped ground mark out a rectangular area of 1’ 3’’wide along the six foot length. This comes from leaving 4.5 inches on each side (the width of a standard brick). Now begin scraping out the soils from this central area with a sharp spade slowly, wetting the ground from time to time, to a depth of two feet. Once again if edges break, finish them with mud plaster.

Next make the pipe connection of the pit with the toilet. A four feet long, 3’ dia plastic pipe or cement pipe should be more than sufficient. See that the outlet of the pipe is a few inches below the top of the two feet deep pit and ensure that there is a gentle slope from toilet to pit. Once again finish off any breakage with mud plaster.

Step 3

Now on the four and a half inch wide sides put a little sand and cement mortar and place on it a single layer of bricks on the sides. Seven and a half bricks will be required on each side with a little space in joints to cover the six foot length. If bricks are not available this step can be skipped but adding the bricks will increase life of pit. About five kilograms of cement would suffice for the purpose.

Set aside a kilo of cement from the remaining ten kilograms and make a thick solution of the rest in water. Pour this with a mug on the sides of the two feet deep mud pit to line it with a cement solution. Some cement will flow to the bottom of the pit. Scrape it out and keep aside.

Now at the bottom of the pit throw in some broken brick rubble of size smaller than three inches and about a kilogram of chopped potatoes. If potatoes are rotting all the better. The potatoes help speed development of anaerobic bacteria that digest sewage later and reduce the time a foul smell will emanate from the tank. Septic tanks emit a foul smell for a few weeks after usage begins. Adding a gas pipe does not help to eliminate it. However after this initial period the tank shall function for decades without emitting any foul smell.

Next cover the pit with the three stone slabs. These will rest on the bricks on sides. Let the cement on the bricks set before placing these slabs or place some folded newspaper on them otherwise the slabs will stick when cement sets and it would not be possible to remove them later for cleaning or repairs. Finally cover the stone slabs and bricks with soil to bring the ground up to grade level or higher as a slightly raised mound so that the area is marked and heavy activity prevented over it. Any gaps in the joints of slabs may be filled with a cement (from the remaining kilo of cement) and mud mortar in ratio of 10:1. Do not use sand for mortar or it may become too strong for removing slabs later at time of cleaning.

Grass can be grown on top of the pit and plants like grape wines on the sides will grow well without watering or fertilization.

When the septic drain gets filled up as will be revealed if water from the toilet does not flow, the soil can be scraped, one of the stone slabs removed (the one furthest from inlet) and the compost taken out with spade for use in farms. Depending on usage this may be once a year or once in several years.