Wish you all a very Happy New Year
Wastes of biodegradable nature are of major concern both in the
villages and cities. Enormous quantities of biodegradable
wastes are being produced from farms, gardens, houses, apartments, markets and
offices. Majority of the wastes are disposed off in the landfills while
some end up in the open space or rivers and water bodies contributing to
pollution. In the villages most of the farmers burn the wastes as it is easier
to manage contributing to global warming and climate change.
Wastes if not managed
scientifically pose a sequel of problems related to their management and
associated health and environmental hazards. Bio-degeadable wastes comprise of
vegetable and fruit peels, garden clippings, and kitchen garden wastes etc
which are degradable.
Wastes, though considered
waste are not mere waste. They are the misplaced resources which can be efficiently utilized
with simple technologies. The waste management technology should not just aim
at turning the waste benign, rather focus in bringing those resources back into
place. In other words, the useless wastes should be transformed into a
value-added product that can initiate income-generating enterprise. The
approach should be “Turning filth to Wealth”.
Different methods are
adopted to mitigate the biodegradable wastes generated. Composting is one of
the techniques, which is widely followed. The composts that are produced by
inappropriate methods reveal their adverse features during storage, marketing
and use. The associated problems include foul odours, fire, environmental
pollution, nuisance, insect infestation and bursting of compost bags.
Phytotoxicity of such composts is also a serious problem, which impairs crop
growth and yield when used in agriculture. In addition, there are problems of
the compounds like amines, sulphamines, mercaptans, skatoles etc. To solve the
gamut of problems related to the conventional composting methods, vermitechnology is one of the alternatives.
Vermitechnology
Vermitechnology is the method of converting wastes into compost by
use of earthworms. Good quality compost is produced in a short period depending
upon on the number of earthworms. In other words about 4-5 kg of wastes can be
composted by 1000 worms (approximately 1 kg) in a day. The commonly used
earthworms like Eudrillus sp. Perionyx
sp., Eisenia sp. or any locally available surface feeding (epigeic)
earthworms can be collected from the nearby soil and then used in
Vermitechnology. A simple and efficient method of Vermitechnology “Pusa
Vermitech” was developed during my Masters degree program at Indian
Agricultural Research Institute (IARI), Pusa, New Delhi in 1996 which is
low-cost and is ideal for the farmers. Now this method is widely adopted in
India, Nepal, Sri Lanka, Italy and Costa Rica.
Vermitechnology can be undertaken in a tank or on the soil
surface. The tank can be constructed with bricks or stones depending on the
availability of materials. The height of the tank should be 0.75 metres, width
1 metre and length can be 3 - 4 metres or even more. The base of the tank
should have a slight slope directing towards two drainage holes.
Method:
The methodology is simple and can be carried out by adopting the following
steps;
1. Basal Sand Layer
The first layer (5-10 cm) at the base is of sand as it helps in
the drainage of excess water and also prevents the movement of worms into
deeper layers of soil or out of the tank.
2. Dung Layer
On the top of the sand, a layer of one month old dung is laid.
This layer is approximately 3-5 cm. thick.
3. Waste Layer
On the top of this dung layer all the biodegradable wastes are put
and the tank is filled up to the brim (65 cm) with the waste.
4. Soil Layer
The wastes are covered with a thin layer (1-2 cm) of soil.
5. Dung Layer
Above the soil layer mature dung is uniformly spread (3-5cm) which
forms the top layer in the tank.
In other words, the wastes are sandwiched by two layers of mature
dung. The contents are moistened with water (40-50% moisture level) for 7 days
to pre-decompose the contents. After pre-decomposition, worms are introduced
(1000 worms which would be approximately 1 kg for 100-150 kg of wastes) and
watered regularly to maintain 30-40 % moisture level for better activity of
worms.
Watering is done in such a way the contents in the tank are not
too soggy or too moist as it results in anaerobiosis of earthworms causing mortality.
The tank is covered by a gunny sack in summer months to avoid evaporation of
moisture. In places where the predators like rats, lizards, pigs are a major
problem; the tanks can be covered with wire mesh to prevent them feeding on the
earth worms.
Collection of Vermicompost
Vermicompost appears on the top of the tank in the form of
pellets. When this layer of vermicompost becomes a few centimetres thick
watering should be avoided for 3-4 days. The reduced moisture at the top layer
will force the worms to move down towards the lower layers. The compost formed
is heaped in the corners of the tank by gently scrapping with a shovel or a
wooden raft and left for a day or two. By this method of collection of wastes
the young worms and the adult worms are not damaged while handling. In this
manner the compost can be collected every 7-10 days till 80% of the material is
collected i.e 10-15 cm layer is left
at the base. The tank/heap should be refilled with pre-decomposed wastes.
Pre-decomposition of wastes
Before filling the fresh wastes into the tank it has to be pre-decomposed to
avoid the heat that is generated during the decomposition process which
otherwise can kill the earthworms. Also pre-decomposition helps to turn the
wastes bit softer facilitating the earthworms to feed upon. Pre-decompostion is
done as mentioned below;
1.
Spread a thin layer (10 cm) wastes
and sprinkle cow dung and moisten it.
2.
Likewise make layers of waste and
cow dung up to 0.5 metres height.
3.
Moisten the heap regularly with
water for 10 days.
4.
During the process high
temperature develops and cools down in a week.
5.
Check the temperature of the heap
by inserting a stick.
6.
If the stick heats up, leave the
decomposing material for 3-4 days more and when the temperature is normal then
only it should be used.
Refilling the Tank or Heap
Such pre-decomposed material is put on the heap or tank up to 75%
of its height. The standard procedure of Vermitechnology as mentioned above is
continued i.e over the pre-decomposed waste, thin layer soil is spread and above
it dung is spread. The worms come on the top and start feeding on the
waste.
Precautions
1. Check the temperature of heap /tank by introducing a stick. If
the stick heats up worms should not be introduced nor refilled. Nowadays
temperature measuring probes are also
2. The tank /heap should be moistened with water regularly.
3. Appropriate shade should be provided at the site where
Vermitechnology is undertaken.
4. Wherever the predators like rats, lizards, pigs etc., are
found, wire mesh should be put on the top of the tank.
It is very important that
the method adopted should be scientific
degrades the waste faster, the end product i.e. compost should fit into the
basic criteria (i.e. quality parameters) of marketing of manure. The
compost should not have any bad odour
which will not be acceptable by the users. To be the choice of consumers, the
final product should be friable and uniform with positive visual
characteristics and attractive packaging. Mere
degradation is not composting, rather composting is a scientific way of desired
degradation.
There is a tremendous scope
for the production of quality manure by vermitechnology. The growing awareness
about organic farming, home and kitchen gardens
world over is an added advantage and a positive step in launching a
quality product at this juncture. This will
not only manage the wastes but also would generate income.