How often do worms breed? The breeding cycle is approximately 27 days from mating to laying. Worms can double in population every 60 days. How long do worms live? We don't know the extreme of the scale, but 2-3 years under the right conditions is common. A laboratory experiment in the UK is said to have had a worm in the laboratory for over ten years. We have not been able to verify this. Do worms take up heavy metals? There is much anecdotal, but no scientific data to confirm this. Our research will establish the extent.

Has much research been conducted? Professor Clive Edwards (Ohio State University) has been responsible for many years of valuable research into earthworm ecology. How much do worms eat? Research shows more than their body weight each day. How many worms do you need to consume 80 tonne per day? Worms range in size from near thread like hatchlings to several centimetres as adults. Estimating the number of worms by the feed conversion method is inaccurate. However, if all the worms were adult with an average weight of 1 gram, you would need more than 80 million. What can kill worms? Worms are sensitive to major fluctuations in pH, lack of oxygen and certain toxic chemicals. Research has established that worms are resilient to many chemicals that are toxic to humans. It appears that the vermiculture process will break down some of these chemicals into benign components. Sewage sludge and piggery sludge provide an excellent base where the quality and contaminant levels are predictable and manageable.

Earthworms are involved in one of the most critical jobs in the ecosystem. They recycle or reuse the basic materials that plants and animals need to survive. By eating this waste, earthworms help to decompose (break down) the material into smaller, simpler parts that can be reused by other organisms. Without this process of decomposition, the basic chemicals of life would stay locked up and unavailable for use by other organisms.

Earthworms occupy a special place in the hierarchy of soil inhabitants. The reasons are:

• Almost universal distribution and their large numbers.
• They are large enough and strong enough to reshape the soil and move it about to make burrows
• Their casts are commonly rich in plant nutrients.
• They are prehistoric in origin, being part of the fundamental natural organic recycling and pathogen reduction system.

1. Worms in the soil improve the structure through:

Creation of a worm-made sponge in the top soil. This "sponge" has certain qualities that enhance the soil.

a) Increased channels. The worms burrow through the soil and break down the root mat. They also open up channels for oxygen and rainfall to penetrate.

b) Increased moisture. This results in the worm-populated soil becoming wet faster and deeper and consequently the soil that has been in contact with worms holds the moisture longer.

c) Increased plant-growth. The tunnels created by worms are coated with mucus, which is rich in nitrates, and plant roots take advantage of the tunnels as easy-growth channels and pathways. Higher available nutrient content. As a result of the combined action of the worms and their bacteria.

2. A positive effect on the Carbon/Nitrogen Mix.

a) The litter produced by plants mostly has a carbon:nitrogen ratio greater than 20:1. If the nitrogen level is above 20:1 it cannot be absorbed by plants and the soil beneath and surrounding the litter could become acid, the soluble mineral locked up and the soil itself then becoming less fertile.

b) Therefore, it is essential that the carbon:nitrogen ratio be reduced to 20:1 or less, and this is greatly assisted by worms feeding on the rotting litter. Although the rotting is started off by bacterial action, it is accelerated by worms eating the litter and excreting the castings. It can therefore be strongly argued that without the action of worms, the forests of the world might be very different. The same can be said of our fertile plains. The castings produced by worms act as a fertiliser.

c) This conversion process is optimised in the Vermitech vermiculture system. The beds produce ideal conditions for worms to convert the organic material.

In summary, worm worked soils exhibit enhanced water holding capacity, improved water infiltration , enhanced microbial activity and significant mineralisation of organic Nitrogen .

Worms and Disease

Worms are subject to very few diseases. The bacteria fostered in their gut and excreted with their castings are benevolent and produced in such overwhelming numbers that disease-producing bacteria find life very difficult in an earthworm environment. Most disease-producing bacteria require an oxygen-free (anaerobic) environment, whereas the environment created by earthworms is oxygen-rich (aerobic). This is the reason why worm castings are usually very low in disease-producing bacteria. Accordingly, worm beds and their castings are essentially free of harmful pathogens and viruses. This makes worms ideal for the stabilisation of all forms of putrescible wastes.

Earthworms in Waste Management

Earthworms, in dense culture and in large quantities, can physically handle virtually any biological waste. It is this system that Vermitech has harnessed and developed to a capacity that makes it viable as an industrial process capable of sustained commercial operation.

For millennia earthworms have been preparing soil for the introduction and development of higher vegetation under conditions often originally no less harsh than those created by chemical fertilisers added today. Earthworms have an added value. While they devour our biological wastes, thus decreasing our disposal problems, they are also and concurrently manufacturing two new products - earthworm castings known as vermicast (or vermicompost) and more earthworms.

Earthworms in Sludge Management 

This is a relatively new process sometimes known as vermi-composting or vermi-stabilisation. It is not a true composting as the process does not involve heat. Rather vermiculture is a very complex mechanical, chemical and biological transformation.

Given the nature of the worm behaviour and the bed design and management, the resultant product has a higher stabilisation and soil supplement value than traditional composting which relies on mechanical incorporation of sludge with green waste in large quantities.

There are many fundamental factors that have to be evaluated to assure the technical and economic success of sludge conversion. These factors include:

a) how earthworms affect and are impacted by sludge characteristics given the wide range of different sludges, Vermitech's research has developed formulae for handling all sludge types.Feeding is done in a controlled manner. These two factors ensure ideal environment for worm activity.

b) the comparative ability of different earthworm species to grow and reproduce in sludge, and the effect of mixed earthworm species in a vermi-stabilisation system.

c) the efficient handling and management of the entire conversion cycle. There is a fine balance in the operation of the beds to maintain optimum performance. The Operations Procedures and Quality Assurance System are needed to maintain peak performance and minimise problems

d) The maintenance of aerobic conditions. The worms maintain aerobic conditions in the mixture, ingest solids, convert a portion of the organic into worm biomass and to respiration products and expel the remaining stabilised matter as discrete material (castings). The worms and the micro-organisms act symbiotically to accelerate and enhance the decomposition of the organic matter.

Vermi-stabilisation represents a technology that is environmentally sound, but requires skilled management. Large scale Vermi-stabilisation is now an established technology that can still be classified as innovative. It is directly analogous to the bacterial systems in most sewage plants, but operating on the biosolids using worms (with their internal bacteria and enzymes) instead of cultured bacteria of the sewage plant digester. So how does the Worm's Digestive System Work?

The Worm's Digestive System

The worm's digestive system consists of a buccal chamber, oesophagus, crop, gizzard and intestine. Earthworms use organic matter as a source of nutrition but depend upon other micro-organisms such as bacteria and fungi for their nutrients. The nutrients are extracted from the large quantities of micro-organisms in waste materials as they pass through the worm's gut. (Figures taken from Lee [1985])

Like birds, worms have a gizzard where the food is ground to a fine consistency. It is then acted upon by a secretion of calcium carbonate. (This is one reason, worms help to neutralise acid soils). The food is next passed through the actual digestive tract further processing by means of a variety of enzymes, excreted both by the worms and importantly, by bacteria. (the enzymes are also thought to influence the pH of the soil). During the digestive process, a proportion of insoluble minerals are converted to a plant-available soluble form, cellulose is partially broken down by bacteria and carbon is released to the atmosphere as carbon dioxide. This digestive process is carried out by enzyme-producing bacteria and when the castings are excreted, the bacteria and enzymes are excreted along with them. The bacteria are soil benevolent and once in the soil, continue the work they carried out in the worm's gut. An analysis of worm castings, when compared to the parent soil reveals a huge increase in bacterial count. Research has shown that the numbers of bacteria contained in the ingested material increased by up to 1,000 times while passing through the worm's gut. The actual number of soil-benevolent bacteria in soils due to the presence of worms can exceed 2,500,000 per gram.

The Vermitech worm beds optimise the consumption rate of waste plus it allows a large contact time for continued bacterial and enzyme activity. As a result of the combined action of the worms and their enzymes and bacteria, an analysis of worm castings when compared to the parent soil shows approximately: 7 times the available phosphorous 6 times the available nitrogen 3 time the available magnesium 2 times the available carbon 1.5 times the available calcium

The total mineral balance is not increased by worm activity. Rather the conversion changes the amount of nutrient available to the plant. The minerals have been changed form an insoluble form to a plant - available, soluble form. This has major implications for the reduction in the negative impact caused by nutrient leaching into our water systems. Vermicast's nutrients being more readily available are absorbed when applied reducing leaching and run-off. 

A Solution to Nutrient Run-off and Algal Bloom

The substitution of vermicast for high-density chemical fertilisers will reduce nutrient run-off. This has wide ranging implications for not only farmers in catchment areas, but also for recreational areas bordering rivers such as golf courses and parks.