What is worm composting?

Worm composting is using worms to recycle food scraps and other organic material into a valuable soil amendment called vermicompost, or worm compost. Worms eat food scraps, which become compost as they pass through the worm's body. Compost exits the worm through its' tail end. This compost can then be used to grow plants. To understand why vermicompost is good for plants, remember that the worms are eating nutrient-rich fruit and vegetable scraps, and turning them into nutrient-rich compost.

Materials to use (and avoid) in a classroom worm bin

For millions of years, worms have been hard at work breaking down organic materials and returning nutrients to the soil. By bringing a worm bin into the house, you are simulating the worm's role in nature. Though worms could eat any organic material, certain foods are better for the classroom worm bin.

We recommend using only raw fruit and vegetable scraps. Stay away from meats, oils and dairy products, which are more complex materials than fruits and vegetables. Thus, they take longer to break down and can attract pests. Cooked foods are often oily or buttery, which can also attract pests.

Avoid orange rinds and other citrus fruits, which are too acidic, and can attract fruit flies. Try to use a variety of materials. We have found the more vegetable matter, the better the worm bin. Stay away from onions and broccoli which tend to have a strong odor.

Setting up a worm bin

Setting up a worm bin is easy. All you need is a box, moist newspaper strips, and worms. To figure out how to set up a worm bin, first consider what worms need to live. If your bin provides what worms need, then it will be successful. Worms need moisture, air, food, darkness, and warm (but not hot) temperatures. Bedding, made of newspaper strips or leaves, will hold moisture and contain air spaces essential to worms.

You should use red worms or red wigglers in the worm bin, which can be ordered from a worm farm and mailed to your school. The scientific name for the two commonly used red worms are Eisenia foetida and Lumbricus rubellus.

Containers

When choosing a container in which to compost with worms, you should keep in mind the amount of food scraps you wish to compost, and where the bin will be located. A good size bin for the classroom is a 5- to 10- gallon box or approximately 24" X 18" X 8". The box should be shallow rather than deep, as red wigglers are surface-dwellers and prefer to live in the top 6" of the soil..

Whether you choose a plastic, wooden or glass container to use as a worm bin is a matter of personal preference based primarily on what is available. Some teachers have extra aquariums available. Some have wooden boxes which they would like to reuse. Others may prefer to buy or reuse a plastic container, such as commercially manufactured storage bin (e.g. "Rubbermaid," "Tucker," "Sterilite").

No matter what material you choose, make sure to rinse out the container before using. For wooden bins, line the bottom with plastic (e.g. from a plastic bag or old shower curtain). Cover the bin with a loose fitting lid. This lid should allow air into the bin.

Harvesting

If you take care of your worms and create a favorable environment for them, they will work tirelessly to eat your "garbage" and produce compost. As time progresses, you will notice less and less bedding and more and more compost in your bin. After 3-5 months, when your bin is filled with compost (and very little bedding), it is time to harvest the bin. Harvesting means removing the finished compost from the bin. After several months, worms need to be separated from their castings which, at high concentrations, create an unhealthy environment for them.

To prepare for harvesting, do not add new food to the bin for two weeks. Then try one of two methods for harvesting:

Push all of the worm bin contents to one half of the bin, removing any large pieces of undecomposed food or newspaper. Put fresh bedding and food scraps in empty side of bin. Continue burying food scraps only in freshly bedded half.

Over the next 2-3 weeks, the worms will move over to the new side (where the food is), conveniently leaving their compost behind in one section. When this has happened, remove the compost and replace it with fresh bedding. To facilitate worm migration, cover only the new side of the bin, causing the old side to dry out and encouraging the worms to leave the old side.

Hands-On Method:

Dump the entire contents of the worm bin onto a sheet of plastic or paper. Make several individual cone-shaped piles. Each pile will contain worms, compost and undecomposed food and bedding. As the piles are exposed to light,, the worms will migrate towards the bottom of the pile. Remove the top layer of compost from the pile, separating out pieces of undecomposed food and newspaper. After removing the top layer, let pile sit under light for 2-3 minutes as the worms migrate down. Then remove the next layer of compost. Repeat this process until all of the worms are left at the bottom of the pile. Collect the worms, weigh them (for your record keeping) and put them back in their bin with fresh bedding.

Regardless of which method you choose, the compost you harvest will most likely contain a worm or two, along with old food scraps and bedding. If you are using the compost outdoors, there is no need to worry--the worms will find a happy home and the food scraps and bedding will eventually decompose. If you are using the compost indoors, you may want to remove old bedding and food scraps for aesthetic purposes and ensure that there are no worms in the compost. Though the worms will not harm your plants, the worms may not like living in a small pot.

For both methods, you may continue to compost your food scraps after harvesting. Just add fresh bedding and food scraps. If, for some reason, you do not want to continue composting, please offer the setup to another teacher or to someone who will take the worm bin home. Anyone with a garden will find the worm compost extremely valuable. As a last resort, if you cannot find anyone who wants good worm compost, you may add the worms to a garden bed.

Using worm compost

You can use your compost immediately, or you can store it and use it during the gardening season, or whenever. The compost can be directly mixed with your potting soil or garden soil as a soil amendment, which helps make nutrients available to plants. Or, the compost can be used as a top dressing for your indoor or outdoor plants.

You can also make "compost tea" with your compost. Simply add 1-2" of compost to your water can or rain barrel. Allow compost and water to "steep" for a day, mixing occasionally. Then water plants as you normally would. The resulting "tea" helps make nutrients already in the soil available to plants.

Biology of worms

Worms can live for about one year in the worm bin. If a worm dies in your bin, you probably will not notice it. Since the worm's body is about 90% water, it will shrivel up and become part of the compost rather quickly. New worms are born and others die all the time.

Worms are hermaphrodites, which means they are both male and female at the same time. In order to mate, they still require two worms. The worms line up in opposite directions near their band (or clitellum), which contains some of the sexual organs. The worms are attached for about 15 minutes while they exchange sperm cells. Several days later, eggs come in contact with the sperm cells and form a cocoon, or egg case. The cocoon separates from the worm, then fertilization takes place. Inside the cocoon, 2-5 baby worms may be found.

The baby worms live in the egg case for at least 3 weeks, sometimes longer depending on the surrounding conditions. For example, in the winter time, baby worms may stay in the cocoon for many weeks until the temperature worms up again. When the baby worms eventually crawl out, they are the thickness of a piece of thread and possibly 1 cm 1/4" long. Usually the worms appear white, as they have not yet developed pigmentation, or do not have enough pigmentation (or blood) to be seen.

Successful vermicompost projects

Many schools have been successfully composting with worms over the past few years. Some elementary school classes keep worm bins as part of an environmental unit, others for science. In most cases, teachers find a variety of multidisciplinary ways to use a worm bin. For example, one class called their room the "Worm World." Writing assignments, math lessons and art work focused on worms as a theme.

 Solid wastes should be bio-composted before applying to soil in order to achieve biological transformation of the organic matter and avoid potential risks of pathogens. Composting has been increasingly popular as an alternative to dispose waste in their recent years as benefiting waste recycling option. Composting reduces and stabilizes the waste and coverts it into hygienic and safe products which add economic value to the final product.     

Earthworms – A Boon to Mankind

Lakshmi Priya Thyagarajan^a, T.Meenambal^b

a Department of Biotechnology, Government College of Technology, Coimbatore-641013.

b Department of Civil Engineering, Government College of Technology, Coimbatore-641013.

Industrialisation, urbanisation and overpopulation are the main reasons of increase in solid waste. The disposal of wastes now-a-days has become a prime concern. According to an estimate that India produces about 3000 million tones of wastes annually and more than 60% are of decomposable. With the progressive increase in the size of the world population resulted large volumes of organic wastes produced all over the world. The disposal of bio-degradable solid wastes from domestic agriculture and industrial sources has caused increasing environmental and economic problems, especially in developing countries has alarmed authorities on waste disposal issues. Therefore, various alternatives have been looked into to reduce waste disposal strategies like landfills, incineration and bioremediation. The bioremediation allows the conversion of putrescible wastes into value added products such as vermicompost and optimising this sludge waste to becoming an organic fertiliser.

Earthworms play an important role in soil as ‘environmental managers’. The Greek Philosopher, Aristotle, named them the ‘Intestine of Earth’. In India, so far, 509 species referable to 67 genera and 10 families have been reported (Kale, 1991). Earthworms promises to provide cheaper solutions to several social, economic and environmental problems of human society. They are both ‘protective’ and ‘productive’ for environment and society. They protect the environment (by remedifying contaminated soil, degrading the solid wastes and purifying wastewater) and also produce nutritive ‘protein rich feed materials’ for cattle and ‘organic fertilizers’ for the farmers to grow safe and chemical-free organic foods for society (Lee, 2003).

Earthworms occur in diverse habitats specially those which are dark and moist. They can tolerate a temperature range between 5℃ to 29℃. A temperature of 20℃ to 25℃ and moisture of 60-75% is optimum for good worm function. Earthworms multiply very rapidly. Studies indicate that they double their number at least every 60-70 days. Given the optimal conditions of moisture, temperature and feeding materials earthworms can multiply by 28 i.e. 256 worms every 6 months from a single individual. Each of the 256 worms multiplies in the same proportion to produce a huge biomass of worms in a short time. The total life-cycle of the worms is about 220 days. They produce 300-400 young ones within this life period (Hand, 1988). Earthworms continue to grow throughout their life.

Some of the virtues of earthworms:

a)      Disinfects the waste

Earthworms routinely devour on the protozoa, bacteria and fungus as food in any waste materials or soil where they inhabit. They seem to realize instinctively those anaerobic bacteria and fungi are undesirable and so feed upon them preferentially, thus arresting their proliferation. More recently, Dr. Elaine Ingham has found in her research that worms living in pathogen-rich materials (e.g. sewage and sludge), when dissected, show no evidence of pathogens beyond 5 mm of their gut. This confirms that something inside the worms destroys the pathogens, and excreta (vermicast) becomes pathogen-free (Satchell, 1983; Hand, 1988). In the intestine of earthworms some bacteria and fungus (Pencillium and Aspergillus) have also been found (Singleton et al., 2003). The earthworms also release coelomic fluids that have anti-bacterial properties and destroy all pathogens in the waste biomass (Pierre, 1982).They produce ‘antibiotics’ and kills the pathogenic organisms in the waste and soil where they inhabit and render it virtually sterile. It was reported that the removal of pathogens, faecal coliforms (E. coli), Salmonella spp., enteric viruses and helminth ova from sewage and sludge appear to be much more rapid when they are processed by E. fetida. Of all E. coli and Salmonella are greatly reduced (Bajsa, 2003).

b)      Lowers Green House Gases emissions

Studies have established that vermicomposting of wastes by earthworms significantly reduce the total emissions of greenhouse gases in terms of CO₂ equivalent, especially the highly powerful GHG nitrous oxide (N₂O). Worms significantly increase the proportion of ‘aerobic to anaerobic decomposition’ in the compost pile by burrowing and aerating actions leaving very few anaerobic areas in the pile, and thus resulting in a significant decrease in methane (CH₄), nitrous oxide (N₂O) and also volatile sulfur compounds which are readily emitted from the conventional (microbial) composting process (Mitchell, 1980). Analysis of vermicompost samples has shown generally higher levels of available nitrogen (N) as compared to the conventional compost samples made from similar feed-stock. This implies that the vermicomposting process by worms is more efficient at retaining nitrogen (N) rather than releasing it as N₂O. 

c)      Reducing the loads on landfills

Millions of tons of municipal solid waste generated from the modern society are ending up in the landfills every day, creating extraordinary economic and environmental problems for the local government to manage and monitor them for environmental safety (emission of greenhouse and toxic gases and leachate discharge threatening ground water contamination). Earthworms have real potential to both increase the rate of aerobic decomposition and composting of organic matter, and also to stabilize the organic residues in them earthworm participation enhances natural biodegradation and decomposition of organic waste from 60 to 80% over the conventional composting. Given the optimum conditions of temperature (20-30℃) and moisture (60-70%) about 5 kg of worms (numbering approx.10,000) can vermiprocess 1 ton of waste into vermicompost in just 30 days (Visvanathan, 2005).

d)      Bioremediation of contaminated sites

Polyaromatic Hydrocarbons (PAHs) are priority pollutants and cause great concern with respect to human health and environment. They are inherently ‘recalcitrant hydrocarbons’, and the higher molecular weight PAHs are very difficult to remediate. Earthworm species  L. rubellus degraded spiked PAHs phananthrene & fluoranthene (100 μg/kg of soil). Losses of both PAHs occurred at a faster rate in soils with earthworms, than the soil without worms. After 56 days 86% of the phenanthrene was removed.  E. fetida was also found to degrade the  PAHs. The concentration of anthracene decreased by 2-fold after addition of earthworms, benzo(a)pyrene decreased by 1.4-fold and phenanthrene was completely removed (100%) by earthworms (Contreras-Ramos et al., 2006).

Studies with earthworm species Eisenia fetida on oil contaminated soil revealed that worms significantly decreased oil contents in comparison to the control. It also successfully treated high molecular weight hydrocarbons ‘asphaltens’ from the Prestige Oil Spill. Earthworms mineralized the asphaltens thus eliminating it from the system. It also decontaminated complex hydrocarbons polluted soil (Tomoko, et al., 2005).

Polychlorinated Biphenyls (PCBs) are a group of oily, colorless, organic fluids belonging to the same chemical family as the pesticide DDT. They constitute a family of chemicals with over 200 types, and are used in transformers and power capacitors, electrical insulators, as hydraulic fluids and diffusion pump oil, in heat transfer applications, as plasticizers for many products. PCBs are categorized as ‘unusually toxic’ and ‘persistent organic pollutant’ (POPs). They have serious adverse effects on the human health and the environment. PCB contaminated soil treated with earthworms resulted in significantly greater PCB losses (average 52%) when compared to the soil without earthworm (Singer, 2001).

e)      Recycling of industrial waste

Recycling of guar gum waste done using vermicomposting technology for a period of 150 days by the earthworm Perionyx excavates, the author reported that the treatment with 60:20:20 ratio of guar gum industrial waste: cow dung: saw dust were ideal for the growth, reproduction and zero mortality of earthworms producing nutrient rich vermicompost (Surendra Suthar,2006).

Surender Suthar and Sushma Singh (2008) investigated the use of distillery sludge with cow dung in different proportions viz. 20%, 40%, 60% and 80% using earthworm species Perionyx excavates for 90 days. They concluded that the treatment with 40% of cowdung was ideal for the vermicomposting of distillery sludge. They reported resulting vermicompost showed reduction in the concentration of metals like Zinc, Iron, Manganese and Copper when compared to the raw sludge, thus reducing metal toxicity and increasing nutrient profile in the sludge. The biological sludges from the municipal sewage plants were stabilized by vermicomposting with Eisenia foetida variety earthworm, thereby reducing the toxicity of direct application of these wastes (Masciandro et al 2000).

f)       Medicinal Value

Traditional medicinemen in China and Philippines used earthworms in forkloric healings of many sickness such as to cure fever, inflammation of different parts of the body, stomach-aches and toothaches, rheumatism and arthritis, to cure mumps and measles and even to make child delivery easier by faster contraction of the uterus and reducing labour pains. China has been using earthworms in traditional healing for 2,300 years (Wengling, 2000).

Lumbrokinase (LK) is a group of 6 ‘proteolytic enzymes’ and recent researches suggest  that it may be effective in  treatment and prevention of ‘ischemic heart disease’ as  well as ‘myocardial infarction’, ‘thrombosis’ of central vein of retina, ‘embolism’ of peripheral veins, and ‘pulmonary embolism’. It is now being used in the treatment of ‘cerebral infarction’. Japanese scientists also confirmed the curative effects of ‘lumbrokinase’ experimentally in the 1980s (Qingsui, 2003).

Scientists in the University of Colorado, U.S. believe that researches into earthworms may provide an insight into increasing the longevity of humans up to around 120 years. By exposing the earthworms to stress they identified the genes (biomarker of ageing) which may allow modifying humans ‘stress response system’ in order to extend their life.

g)      Wonder Probiotics

Worms are rich in Vitamins A and B. There is 0.25 mg of Vitamin B1 and 2.3 mg of Vitamin B2 in each 100 gm of earthworms. Vitamin D accounts for 0.04-0.073% of earthworms’ wet weight. Thus worms are wonderful probiotic feed for fish, cattle and poultry industry.

Hence earthworms no doubt justifying the beliefs of Dr. Anatoly Igonin one of the great contemporary vermiculture scientist from Russia who said ‘Earthworms create soil and improve soil’s fertility and provides critical biosphere’s functions: disinfecting, neutralizing, protective and productive’. It’s true to conclude that earthworms are ‘Boon to Mankind’.

                References

1.       Bajsa, O, J. Nair, K. Mathew and G. E. Ho “Vermiculture as a Tool for Domestic Wastewater Management,” Water Science and Technology, IWA Publishing, Vol. 48, No. 11-12, 2003, pp. 125-132. 

2.       Contreras-Ramos S. M., S. Alvarez-Bernal and L. Den-dooven, “Eisenia fetida Increased Removal of Polycyclic Aromatic Hydrocarbons (PAHs) from Soil,” Environmental Pollution, Vol. 141, No. 3, 2006, pp. 396-401.

3.       Hand.P, “Earthworm Biotechnology,” In: R. Greenshields, Ed., Resources and Application of Biotechnology: The New Wave, Macmillan Press Ltd., US, 1988.

4.       Kale, R.D. 1991. Vermiculture : Scope for new bio-technology. Ed. Director, Zoologica Survey of India, Calcutta. PP 101-103.

5.       Lee.C, “Environment Protection, Biotechnology and Earthworms Used to Enrich Farmers for Organic Farming,” Taihai Publishers, Beijing, 2003.

6.       Masciandaro. G, Ceccanti. B,Garcia.C, 2000. “In situ” vermincomposting of biological sludges

and impacts on soil quality ,Soil Biology & Biochemistry, 32, 1015-1024.

7.       Mitchell.M.J, S. G. Horner and B. L. Abrams, “Decomposition of Sewerage Sludge in Drying Beds and the Potential Role of the Earthworm Eisenia fetida,” Journal of Environmental Quality, Vol. 9, No. 3, 1980, pp. 373-378.

8.       Pierre,V., R. Phillip, L. Margnerite and C. Pierrette, “Anti-bacterial Activity of the Haemolytic System from the Earthworms  Eisinia foetida Andrei,”  Invertebrate Pathology, Vol. 40, No. 1, 1982, pp. 21-27.

9.       Qingsui, C, “A New Medicine for Heart Diseases Containing Enzyme Activator Extracted from Earthworms,” In: Lopez & Alis,  The Utilization of Earthworms for Health Remedies, 2003.

10.   Satchell,, J. E.  “Earthworm Ecology—From Darwin to Vermiculture,” Chapman and Hall Ltd., London, 1983, pp. 1-5.

11.   Singer.A.C, W. Jury, E. Leupromchai, C.-S. Yahng and D. E. Crowley, “Contribution of Earthworms to PCB Bioremediation,” Journal of Soil Biology & Biochemistry, Vol. 33, No. 6, 2001, pp. 765-775.

12.   Singleton, B. F D. R.. Hendrix, D. C. Coleman and W. B. Whitemann, “Identification of Uncultured Bacteria Tightly Associated with the Intestine of the Earthworms Lumbricus rubellus,” Soil Biology and Biochemistry, Vol. 35, 2003, pp. 1547-1555.

13.   Surender Suthar and Sushma Singh  2008, Feasibility of vermicomposting in bio-stabilization of sludge from distillery industry, Sci Total Environ, doi:10.1016/j Scitotenv.2008.02.005.

14.   Surendra Suthar, 2006.  Potential utilization of guar gum industrial waste in vermicompost production, Bioresource Technology.97, 2474-2477.

15.   Tomoko, Y, K. Toyota and S. Hiroaki, “Enhanced Bioremediation of Oil-Contaminated Soil by a Combination of the Earthworm (Eisenia fetida) and Tea Extraction Residue,” Edaphologia, Vol. 77, 2005, pp. 1-9.

16.   Visvanathan.C, J. Trankler, K. Jospeh and R. Nagendran, (Eds.) “Vermicomposting as an Eco-tool in Sustainable Solid Waste Management,” Asian Institute of Technology, Anna University, India, 2005.

17.   Wengling,C and S. Jhenjun, “Pharmaceutical Value and  Uses of Earthworms: Vermillenium Abstracts,” Flower field Enterprizes, Kalamazoo, 2000.