Received Date: Apr 30, 2018 / Accepted Date: May 29, 2018 / Published Date: Jun 05, 2018
Vermicomposting is a biological technique of converting organic wastes in to a rich soil amendment. In this paper a thorough literature is done regarding the impacting factors for a vermicomposting unit followed by design of pit for a vermicomposting and the number of earthworms required for the obtained amount waste. This is further continued with selecting of optimum range for parameters such as Temperature, Potential Hydrogen, Moisture content, TAN.
Keywords: Vermicomposting; Rich soil amendment; TAN; Moisture content; Temperature; Potential Hydrogen
Given the increase in population in leaps and bounds, disposal of waste is a major menace that troubles humankind in this 21st century. According to the latest reports  nearly 38 billion metric tonnes of organic waste are being generated overall the world and India being the second most densely populated country in the world generates nearly 100000 metric tonnes [1,2] organic waste. According to the reports this waste generated is rapidly increasing at the rate of around 1% annually  and by 2047 this would lead up to 260 million tonnes of waste . But the blessing in disguise is that of this quantity of waste, nearly 40%- 60% waste is of organic. In order to develop India in to a super power this menace must be curbed in an eco-friendly manner.
And here comes the solution of modifying this organic waste in to a rich soil amendment. About 2300 years back a great man named Aristotle named Earthworms as intestines of the soil. And after nearly 2300 years his words gained prominence and the solution namely "VERMI-COMPOSTING" came in to picture given its viability, cost effective nature, and the eco-friendly way of disposing the waste. Especially in developing countries like India considering its low versatile capacity to new advancements for nutrient cycling vermi composting is the best aid.
The word vermi is derived from Latin word which means worm  Vermiculture also called as sericulture means the production of earthworms used for a basement of organic material in to rich soil amendment known as VERMI-COMPOST.
This paper has been considered for bio-degradable wastes which primarily consists Paper and food waste. The climatic considerations also play a pivotal role in vermicomposting and this report primarily focuses on cool and humid considerations present in Dehradun. The design considerations depend on the amount of waste. Earthworm specie selected is Eisenia fetida. The above factors might impose constraints on the wider applicability of the process.
Processes undergone during vermicomposting
There science of vermicomposting can be divided in to two types  namely:
(a) Mechanical and Physical
(b) Bio-chemical and Ecological
The mechanical and physical process involves the aeration of the organic matter followed by mixing of both organic material and earthworms. The bio-chemical and ecological process exhibit the inter relation of both the earthworms and microorganism. The interaction between earthworms and microorganisms takes place in three stages micro stage, meso stage, and macro stage. The macro stage interactions are not that prominent and hence importance was given to micro and meso stages of interactions. In the micro stage interaction food requirements for the earthworm are given preference. In the meso stage interactions the way in which the soil characteristics are swayed by the activity of earthworms are studied (Table 1).
|Nutrient release||Dispersal of fungi|
|Break down of organic matter||Populations of plant pathogens|
|Dispersal of vesicular Abuscular Mycorrhizae||Transmission of nematodes|
Table 1: Advantages and disadvantages of interaction between earthworms and microorganisms.
Individual study on the different earthworms coming under the umbrella of Epigeic type.
Named as tiger worm Eisenia fetida is the most common type of earthworm used for vermicomposting. Given its features like rapid rate of growth and easy handling nature (Table 2) it is most preferred for vermicomposting  (Figure 1).
|Characteristic features (Eisenia fetida)|
|2||Temperature tolerance||Up to 35°C|
|3||life cycle||45 to 51 days|
|4||Hatching time for sexual maturity||21 to 30 days|
|5||Rate of cocoon production||0.4 to 1.3 Cocoonday -1|
|6||Incubation period||18 to 26 days|
|7||Life expectancy||4.5 to 5 years|
|8||Average life survival rate at 18°C to 28°C||20 months|
Table 2: Characteristic features of Eisenia fetida.
Named as European night crawler Dendrobaena veneta is used for industrial vermicomposting given its large structure. However, it has share of disadvantages like low reproduction and maturity rates compared E. fetida, P. excavatus and E. eugeniae  (Table 3).
|Characteristic features (Dendrobaena veneta)|
|1||Temperature range||9°C to 30°C|
|2||Moisture content||60% to 85%|
|3||Life cycle||100 to 250days|
|4||Sexual maturity rate||65days|
|5||Cocoon rate||0.28 Cocoon day-1|
|7||Incubation period||42 days|
Table 3: Characteristic features of Dendrobaena veneta.
Although it is not commonly used for vermicomposting citing its preference for organic soil this specie can also be used in vermicomposting  (Table 4).
|Characteristic features (Dendrobaena rubida)|
|1||Life cycle||75 days|
|3||Sexual maturity||54 Days|
|4||Rate of cocoon production||0.45 Cocoons day-1|
Table 4: Characteristic features of Dendrobaena rubida.
Found in moist surfaces Lumbricus rubellus takes more time to mature and less rate of reproduction. Citing this disadvantage this is not suitable for vermicomposting  (Table 5).
|Characteristic features (Lumbricus rubellus)|
|1||Life cycle||120-170 Days|
|2||Temperature range||15°C to 18°C|
|3||Sexual maturity||71 to 91 days|
|4||Rate of cocoon production||0.1 Cocoons day-1|
|5||Maturation time||74-91 days|
Table 5: Characteristic features of Lumbricus rubellus.
It is found in tropical zones. Perionyx excavatus is used in vermicomposting given its advantage of breaking up of organic matter under high range of temperatures  (Table 6).
|Characteristic features (Perionyx excavatus)|
|1||Life cycle||40-71 Days|
|2||Temperature range||20°C to 30°C|
|3||Sexual maturity||55 days|
|4||Rate of cocoon production||6.7 Cocoons day-1|
Table 6: Characteristic features of Perionyx excavatus.
Materials and Methods
The waste is collected from food court, Nescafe, MDC and hostel, in and around UPES Bidholi campus.
Types of waste collected – Food waste and Bio-degradable waste.
Bedding plays a crucial role in vermicomposting by maintaining a proper amount of oxygen and bedding which is done by coarse materials helps in absorbing the oxygen thereby, maintaining the right amount of moisture in the bin. In order to facilitate this considerations a nontoxic, light materials must be considered for bedding.
Materials used for bedding: Newspaper, Cardboards, dry leaves, saw dust, Animal manure and dry grass clippings.
1. The selected bedding material must be shredded so as to minimize the oxygen blockage. If the bedding materials block the oxygen from passing there is a chance of turning the vermicomposting bin in to anaerobic condition and in order to prevent this from happening the bedding material must be shredded.
2. Avoid paper with high chemicals.
3. Top off the bedding material every couple of months.
Selected bedding material – Dry leaves, Animal manure.
Reason – These selected bedding materials provide appropriate nutrients required for the earthworms.
In order to support the bedding materials bedding additives must be added. These additives are used to neutralize the pH of the worm bin.
Materials used as bedding additives – Egg shells, Calcium Carbonate and Rock dust.
Selected bedding additives – Dried egg shell.
Reason– Egg shell is freely available and it is good in neutralizing the acidic nature of the worm pit.
Parameters to be considered for vermicomposting
Temperature: Temperature is the crucial factor in vermicomposting as its affects the metabolism, rate of reproduction and the growth of earthworms. Decrease in temperature below 10°C increases the stress on the earthworms and freezing temperatures can kill the earthworms. Increase in the temperatures can also reduce the activity of the earthworms leading to the reduced reproduction rate finally affecting the activity of vermicomposting.
Necessary care: Adding of extra Insulation in the case of freezing temperatures.Adding of extra bedding materials.
Optimum temperature range – 15°C to 30°C and
Measurement device – Thermometer.
Moisture content: Earthworms contain nearly 75% to 90% of water in their bodies and they breathe from their skin and if they dry up earthworms cannot breathe and will eventually die. The drop in moisture content below 60% can reduce the earthworm breathing rate and in order to avoid this shedding material must be placed to maintain the optimum range of moisture content. Maintaining of optimum level of moisture content is important and hence, moisture content must be measured at a weekly basis [7,8].
Optimum moisture range – 70% to 80%
Calculation of dry moisture content
Procedure: Take 15 grams of waste without any earthworms and dry it for about one day at a temperature in excess of about 100°C and measure the dried weight and calculate the dry moisture content using equation (1).
Potential Hydrogen (pH)
pH is the crucial parameter in vermicomposting and an optimum range of Potential Hydrogen must be maintained. The problem in maintaining pH is that the organic waste presence leads to the increase of acidic content in the pit which is a potential danger to the survival of earthworms .
Optimum range – 6.5 to 7.5
Measuring device – pH meter
Design considerations basis
For 1 pound of waste generated per week of surface area is to be considered (Table 7) .
|Month||Total weight (Kg)||Weight per week (Kg)|
Table 7: The design of the worm pit depends on the organic waste generated.
Average weight – 7664.4 Kg/week (or) 16861.803 pound/week
Surface area required – 16861.803 ft2
Depth – 2 feet
Reason – Earthworms are surface dwellers and their activity is mostly confined to the top surface of the soil and hence, more depth reduces their level of activity. Also suitable aluminium plates with pores are placed for better aeration. Materials Used for construction of pit – Bricks, concrete.
Type of earthworm to be used: Eisenia fetida
Weight of earthworm: 0.25 to 0.4 g worm-1
Worm Length: 2.5 to 65 cm worm-1
Number of worms Required:
Number of Worms Required=15329.
Factors influenced by Pre-treatment:
2. Earthworm survival
3. Nutrients availability
Advantages: Pre-treatment has the advantage of reducing the duration required and also eliminates the disease causing pathogens.
Disadvantages: Pre-treating is known to reduce the nutrient quality of the compost.
Pre-treating is employed in two ways – (1) Thermophillic Precomposting: It is known to reduce the toxic substances in the feed and also allows for the proper mixing of the feed. (2) Mixing precomposting: In this method several materials are mixed in different proportions basing on their composition (Table 8).
|1st Layer||Bedding material|
|2nd Layer||Finely chaffed organic waste (9 Inch)|
|3rd Layer||Bedding material+in equal proportions (2 Inch)|
Table 8: Method of vermicomposting.
Method of approach: Heap Method
Duration: 90 days
Add half of the earthworms in the above mentioned ratio and maintain all the parameters in optimum range as mentioned above. Add remaining earthworms on 45th day without disturbing the pit. And the entire material will be turned in to a rich soil amendment. This output is dried sieved and packed for varying utilities .
Results and Discussion
The obtained output has high maturity rate and high respiration index which is the important parameter in the evaluation of the quality of the manure. The important goal of vermicomposting is the reduction disease causing pathogens in the organic waste. According to reports the organic waste is known to contain 120 virus and bacteria which are harmful to human beings. The compost reduces 75% of the disease causing pathogens. Apart from increasing the nutrients the compost also increases the physical structure of the soil and the water holding capacity  (Table 9).
|Average waste (Kg/week)||7664.4|
|Surface area (ft2)||16861.803 ft2|
Table 9: Germination testing.
Germination testing is the method of testing in which the growth rate of plant is tested. Germination of plant seed shows increased growth in vermicompost rather than commercial yielding. Adding to this there is also evidence that the vermicomposting leads to increased rate of flowers, growth and fruit yielding capability.
Vermi composting a biological process which involves the interaction between earthworms and micro-organisms leading to the formation of earthworm biomass and the vermicompost. In this paper a thorough research is conducted which involves the entire parameters required for vermicomposting, the design consideration which involves the surface area of the pit required and the type of earthworms required, their criteria for selection and the number of worms required are all included in this paper. This paper provides the basis for the process of vermicomposting.
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Citation: Ganti S (2018) Vermicomposting. Int J Waste Resour 8: 342. DOI: 10.4172/2252-5211.1000342
Copyright: © 2018 Ganti S. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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