Technology fact sheet
- Vermitechnology is a simple porcess, which uses earthworms to produce good quality compost through organic waste recycling.
- A tank constructed from locally available materials.
- The initial investment cost for a tank is about US$ 37.
- The total labour time spent on implementing this technology is about three hours in a month.
- About 5 litres of water per m2 of ground surface of the tank are required to operate one tank during 30 days.
- The technology exclusively uses renewable material, recycled from different farming and household activites.
This graph summarizes the results of a sustainability assessment conducted for this technology. The closer the line is to the outer edge of the diagram, the better the technology performs in terms of the particular criterion
What is vermitechnology?
- Vermitechnology is a simple process, which uses earthworms to produce good quality compost (vermicompost) through organic waste recycling. It can be used for managing biodegradable wastes – biomass or organic material that can be degraded or composted.
- The purpose of the technology is to produce good quality compost in a short time. About 4-5 kg of waste can be composted by 1,000 worms (approximately 1 kg) in a day, depending on the worm species. A tank of 5x1x1m allows about 500 kg of waste to be composted by the activity of worms and microorganisms, producing about 250-300 kg of compost in approximately one month.
- The earthworms commonly used for this include Eudrillus sp. Perionyx sp., Eisenia sp. or any locally available earthworms living and feeding on the surface of the soil (epigeic worms).
- Vermitechnology can be practised either in tanks or on the ground. However, the major advantage of a tank is the efficiency of composting and keeping the worms captured from escaping. This way, the worms feed only on the waste and do not escape. This is more productive than ground composting.
- The technology requires little investment and technical know-how.
- Vermiculture (from Latin vermes – worms, and culture – farming) has been practised for at least a hundred years.
- After studying earthworms for 40 years, Charles Darwin (1809-1882) estimated that an acre of British farmland contained 50,000 worms, producing about 18 tons of worm-casts (excreta) per year. The first serious experiments on vermiculture were conducted in Holland in 1970.
- A number of vermiculture studies in several countries including Australia, France, Germany, Italy, the Philippines, Spain and the United States of America have demonstrated the considerable economic potential of the technology.
- In 1996, ‘PusaVermitech’ vermicomposting technique was developed by Mr. A. Thimmaiah at the Indian Agricultural Research Institute (IARI), New Delhi, India. As IARI is also known as ‘Pusa Institute’, this innovative technology was dedicated to the institute and named ‘Pusa Vermitech.
- ‘Pusa Vermitech’ was developed to provide a simple solution to poor farmers.
- This method has become popular in Bhutan, Costa Rica, India, Italy, Nepal and Sri Lanka.
Where it works
- The technology works well in all agro-climatic conditions.
- Typical successful adopters are those interested in natural resource management and organic farming and institutions aiming to convert waste into compost.
- Open ground composting can be used by farmers who cannot afford to construct a tank or who live in mountainous regions where transporting construction material is not easy.
The following describes the process of vermicomposting in a tank made from locally available material.
- The height of the tank can vary from 0.75 to 1 m. The width is about 1 m and length about 3-5 m or more, depending on the region (mountain or lowland).
- The base of the tank should be slightly sloped towards two drainage holes. Figure 1 shows the hole of one cross section.
- The tank consists of five layers as shown in Figure 2. The same layering method can be used for composting on the ground.
- The first layer of 2-3 cm at the base is of sand. The sand helps to drain excess water and prevent the worms from moving into deeper layers of soil or out of the tank.
- A layer of 3-5 cm of month-old dung is laid on top of the sand.
- Next is a 65-cm layer of any biodegradable waste.
- The wastes are covered with a thin soil layer of 1-2 cm.
- The top layer in the tank is month-old mature dung (recognized by the reduced ammonia odour) with a thickness of 3-5 cm and uniformly spread over the soil layer.
- After setting up the five layers of different materials as described above, these are moistened with water for seven days to achieve a 40-50 per cent moisture level to pre-decompose the contents. To assess the moisture level, press a handful of the material. If a few drops of waterseep out, the moisture content is right.
- When the material is partially degraded, which takes about one week in summer and 10-14 days in winter, the worms can be introduced by placing them on top of the pre-decomposed material.
- On average, a tank of 1 m³ contains about 100 kg of pre-decomposed farm waste. As a rule of thumb, about 1,000 worms (approximately 1 kg) are sufficient for 5 m³ of waste or 500 kg of pre-decomposed material.
- Water the compost regularly to maintain a 30-40 per cent moisture level to make the worms more active, but avoid making it too soggy or moist as this will kill the earthworms.Watering once a week in summer (twice a week if temperatures are very high) and once in two weeks in winter is sufficient. A moisture meter can be used to measure moisture content.
- In summer, cover the tank with a gunny sack to avoid evaporation of moisture. To protect the worms from predators such as rats and lizards, cover the tanks with wire mesh.
- Farmers can harvest partial amounts of the degraded compost on a weekly basis. The compost is ready when tiny pellets of the compost start appearing on the top. Harvesting the compost weekly speeds up the process. The compost removed from the top of the heap does not have to be sieved to separate it from the worms.
- If farmers regularly harvest all compost and immediately set up a new batch, about 12-15 batches of compost can be produced in a year using the same tank.
- The vermicomposting site should be covered with a low-cost shelter made of local material.