VERMI-COMPOSTING UNITS

INTRODUCTION
There is a growing realisation that vermi-composting provides the nutrients and growth enhancing hormones necessary for plant growth. The fruits, flowers and vegetables and other plant products grown using vermi-compost are reported to have better keeping quality. A growing number of individuals and institutions are taking interest in the production of compost utilising earthworm activity. Some of them ventured into commercial production as well. As the cost of production of this compost works out to about Rs.1.5 per kg, it is quite profitable to sell the compost even at Rs.2.50 per kg. Other organic manures like neem cake, groundnut cake, etc., are sold around this price.

The process of composting crop residues using earthworms comprise spreading the agricultural wastes and cow dung in layers as 1.5 m wide and 0.9 m high beds of required length. Earthworms are introduced in between the layers @ 350 worms per m3 of bed volume. The beds are maintained at about 40 - 50% moisture content and a temperature of 20 - 30o C by sprinkling water over the beds. The earthworms being voracious eaters consume the biodegradable matter and give out a part of the matter as excreta or vermi-castings. The vermi-casting containing nutrients is rich manure for the plants.
When the commercial scale production is aimed at in addition to the cost of production, considerable amount has to be invested initially on capital items. The capital cost may work out to about Rs.1500 to Rs.2500 for every tonne of compost produced annually. The high variability in the unit capital cost is due to the fact that large units require considerable expenditure on machinery and transport particularly when the source of raw materials is away from the site of production facility and the finished product has to be transported to far off places before being marketed. However, in most of the cases, the activity is viable and bankable. Following are the items required to be considered while setting up a unit for production of vermi-compost.

ABOUT THE WORMS

LOCATION
Suburbs of cities and villages around urban centres can be ideal locations for practice of vermicomposting on a large scale, from the view point of availability of raw material and marketing of the produce. As use of the compost is said to have ameliorative effect on product from fruit, flower and vegetable crops, vermicomposting units may be located in areas with concentration of fruit and vegetable growers and floriculture units.

USE
As the wastes are pulverised as they pass through the worm, the surface area of the material increases which in turn helps as base for nutrients. Vermicompost, apart from supplying nutrients and growth enhancing harmones to plants, improves the soil structure leading to increase in water and nutrient holding capacities of soil. Chemical fertilizer in moderate doses can go along with vermicoposting.

COMPONENTS OF A COMMERCIAL UNIT

Sheds
For a vermi-composting unit, whether small or big, this is an essential item and is required for having the vermi beds. They could be of thatched roof supported by bamboo rafters and purlins, wooden trusses and stone pillars. If the size is so chosen as to prevent wetting of beds due to rain on a windy day, they could be open sheds. While designing the sheds adequate room has to be left around the beds for easy movement of the labour attending to the filling and harvesting the beds.

Vermi-beds
Normally the beds are 75 cm - 90 cm thick depending on the provision of filter for drainage of excess water. The entire bed area could be above the ground. Care should be taken to make the bed with uniform height over the entire width to the extent possible to avoid low production owing to low bed volumes. The bed width should not be more that 1.5 m to allow easy access to the centre of the bed.

Land
About 0.5-1 acre of land will be needed to set up a vermiculture production cum extension centre. The centre will have at least 8-10 sheds each of about 180-200 sq.ft. It should also have a bore well, and pump set or watering arrangement and other equipments as described in the scheme economics. The land can be taken on lease of at least 10-15 years. Even sub marginal land also will serve the purpose.

Buildings
When the activity is taken up on a large scale on commercial lines, considerable amount may have to be spent on buildings to house the office, store the raw material and finished product, provide minimum accommodation to the Manager and workers. The cost of the buildings along with the electrification of these buildings and the vermi-sheds may be included under this item.

Seed Stock
This is an important item requiring considerable investment. Though the worms multiply fast to give the required numbers over a period of 6 months to a year, it may not be wise to wait till such a time having invested on the infrastructure heavily. Thus, worms @ 350 worms per m3 of bed space should be adequate to start with and to build up the required population in about two cycles or three without unduly affecting the estimated production.

Fencing and Roads/Paths
The site area needs development for construction of structures and development of roads and pathways for easy movement of hand-drawn trolleys/wheel barrows for conveying the raw material and the finished products to and from the vermi-sheds. The entire area has to be fenced to prevent trespass by animals and other unwanted elements. These could be estimated based on the length of the periphery of the farm and the length and type of roads/paths required. The costs on fencing and formation of roads should be kept low as these investments are essential for a production unit, yet would not lead to increase in production.

Water Supply System
As the beds have always to be kept moist with about 50% moisture content, there is need to plan for a water source, lifting mechanism and a system of conveying and applying the water to the vermi-beds. Drippers with round the clock flow arrangement would be quite handy for continuous supply and saving on water. Such a water supply/application system requiring considerable initial investment, however, reduces the operational costs on hand watering and prove economical in the long run. The cost of these items depend on the capacity of the unit and the type of water supply chosen.

Machinery
Farm machinery and implements are required for cutting (shredding) the raw material in small pieces, conveying shredded raw material to the vermi-sheds, loading, unloading, collection of compost, loosening of beds for aeration, shifting of the compost before packing and for air drying of the compost, automatic packing and stitching for efficient running of the unit. Costs of providing necessary implements and the machinery have to be included in the project cost.

Transport
For any vermi-composting unit transport arrangement is a must. When the source of raw material is away from the production unit, an off-site transport becomes major item of investment. A large sized unit with about 1000 tonnes per annum capacity may require a 3-tonne capacity mini-truck. With small units particularly with the availability of raw material near the site, expending on transport facility may become infructuous. On-site transport facilities like manually drawn trolleys to convey raw material and finished products between the storage point and the vermi-compost sheds could also be included in the project cost.

Furniture
A reasonable amount could also be considered for furnishing the office-cum-stores including the storage racks and other office equipment. These enhance the efficiency of operations.

Operational Costs
In order to operate the unit, expenditure on some items have to be incurred on a recurring basis. These items include salaries of the staff, wages to the labourers, cost of raw material, fuel cost on transport of raw materials and finished goods, packing material cost, repairs and maintenance, power, insurance, etc. The number of office personnel and labourers have to be decided breaking each activity into a number of sub-activities and for each sub-activity estimating the work involved and the capacity of the labour to finish the work in a given time. The number of persons should be so chosen to keep them engaged throughout by providing enough persons at various work points like stores, vermi-beds and equipping them with adequate number of implements to avoid undue waiting.

Estimate for construction of temporary shed for setting up 200 TPA (tonnes per annum)
vermicompost unit (Size 8 m x 15m x 5.4 m).

* Operational cost for two cycles is capitalized in the first year

For more details see vemicompost techniques in Organic farming