One of the major constraints in the spread of organic farming is the unavailability of good organic manure. But at the same time we are wasting a huge quantity of good organic waste i.e. human waste. The difficulty in the use of human waste is our sentimental objection in handling the material.
Human waste not only pollutes the environment but also helps in the spread of many diseases. The present systems of disposal of human waste have many disadvantages. Some systems need huge capital investment while others cause many environmental problems, such as polluting water bodies. In addition, these systems require very large quantities of water. In water stressed countries like India, it is ill-advised to use 15000 litres of treated and safe drinking water per person every year to flush away faeces and urine.
In this context, our aim should be to collect and reuse the nutrients present in the human waste and at the same time, neutralize the ill effects of the modern disposal systems. For this purpose, Ecological toilets should be used to recover and recycle the nutrients.
Ecological toilets, also known as dry toilets or vermitoilets are effective in disposal of human waste. They use less water, produce organic manure and are environment friendly.
Details of the construction of vermitoilet
A tank measuring 240 cms length, 120 cms width and 60cms height is the major part of the vermitoilet. The tank is to be made above the ground, with 10 cms hollow cement bricks. The narrow side of the tank has to be left open. A partition wall in the centre of the tank divides the tank into two equal compartments. Put a concrete slab on the tank with two holes for defecating. Each hole should be made in the centre of the each compartment. The side of hole has to be raised into a height of 1 cm to prevent the entry of water and urine into the tank. Plaster the slab in such a way that any drop of water falling on the slab should be drained out side through a common point. Put a small plastic tube for easy drainage. A small garden, if maintained behind the tank, can make use of the drainage water. The side wall does not require plastering. The floor of the tank should be strengthened with good cement mortar or concrete. The cost of construction varies from Rs. 2500 – 3000, according to the type of materials used for construction.
Before actually using the tank, spread 4 kgs of fresh cowdung on the floor of one compartment and put around 2000 earthworms in the tank. Cover the open portion of the compartment with bricks using mud for easy dismantling while collecting the compost. Sprinkle some water over the cowdung and cover the opening of the slab with a wooden plank for preventing the entry of flies.
After one week the toilet can be used. While using the toilet, care should be taken that the water used for cleaning purpose is not allowed to go into the tank, where the vermicompost process is expected. After defecating, cover the hole with a lid to prevent the entry of flies. If available, put 250 gms of vermicompost in the tank through the hole every week, so as to enhance the process. Use special type spade for spreading the feacal matter so that the accumulation in the centre point is avoided. After the first compartment gets filled, the second compartment can be used, thus enabling the use of vermitoilet all round the year. After two months, the vermicompost so produced can be removed from the compartment dismantling the temporary wall. From the excreta of each adult person about 12kgs of vermicompost per year can be obtained using the vermitoilet system.
Research about the reduction of pathogen in vermicomposting process showed that, the pathogen levels reduce significantly in the process and met EPA (USA standard) within 144 hours. The reduction of “faecal coliforms” to the EPA standard with in 24 hours, reduction of salmonella and enteric virus and helminth ova levels to the EPA standard in 72 hours and 144 hours respectively was reported.
The emission of foul smell from the vermitoilet is practically nil, since the rate of production of hydrogen sulphide will be reduced very much by the action of worms.
Nutrient status of vermicompost produced from human waste
The N, P, K status of the night soil on oven dry basis is 5.5% N, 4.0% P205 and 2.0% K20. The vermicompost produced from the human waste is richer in nutrients than the one produced from cowdung or farm wastes, since human waste contains more nutrients than other materials.
Storing the vermicompost
The vermicompost produced from the human waste can be packed in polythene bags and stored in a cool place upto a period of two years, without the quality getting deteriorated.
Putting the idea into practice
The very idea of Vermi composting was put to practice by me on establishing a unit in 1998. The materials used for the above were bio-degradable organic matter together with cow dung, otherwise widely used as an organic manure. The benefits of applying vermicompost, so produced for vegetable, banana, paddy, tapioca and coconut gave me ample confidence that this practice would enrich the soil and enhance productivity. The study of various literature developed a thought in me that the use of Human excreta might also bring in allied results. Here one important aspect taken into consideration is the system of applying raw excreta in China and Japan to the cultivated crops. Due to certain cultural objections, Indians do not resort to such practices. So I explored the possibilities of using human excreta as a substitute to cow dung.
Accordingly, in 2004 I constructed a vermitoilet in the premises of my house located at Kattakada, about 20 Kms away from Trivandrum City. The unit is functioning well and the vermicompost produced from that unit has been utilized for different crops in my farm. The compost produced out of the vermitoilet was seen to carry no objectionable odour and the performance of the compost on the plants was highly satisfactory.
Conclusion
Enormous quantities of human excreta are produced each year causing both enviornmental problems and the valuable nutrients can be recycled productively. Vermitoilet can be considered as the best solution of converting human waste into rich organic manure. The management of human waste can be made possible in a cost effective manner so that the nutrients otherwise permanently lost could be reused.
R.C. Sasidharan Nair MSc (Agr), (Rtd) Joint Director of Agriculture
Jaya Bhavan, Azhikkal, Kattakada P.O. Thiruvananthapuram Dist, Kerala 695 572 Phone: 0471-2290840/ Email: agri_co2004@yahoo.com
