Commercial worm farming | Vermiculture
Worm farming and the benefits of vermicompost are well documented and have attracted a lot of interest in recent years, particularly with the increase of 'green' consciousness and growing concern over the sustainability of fossil-fuel based agriculture.
The demand for Organic foodhas increased dramatically as consumers choose Organic over conventionally farmed produce, and often these consumers are prepared to pay a premium for quality Organic products. This consumer pressure, together with the fact that fossil-fuel synthesized fertilizers are unsustainable, harmful to the environment and becoming increasingly expensive, has driven the growing demand for high quality organic fertilizers and pest control.
While domestic worm farming (vermicomposting) is increasingly popular, there are numerous disadvantages associated with scaling up existing vermicomposting techniques, and achieving efficient processing at increased scales. These limitations have hampered the widespread
adoption of commercial vermicomposting operations, and the existing large-scale vermicomposting methods are generally quite crude and inefficient (windrows, beds), or require considerable effort to operate (trays, stacking trays). Promising new vermicomposting technologies include more efficient, notably 'high tech' continuous flow 'reactors' with a mesh floor and 'breaker bar' harvesting mechanism. While this system has its advantages, the engineering and method of working are expensive and technologically complex.
Worm composting (vermicomposting) breaks down organic wastes, rapidly transforming them into a stable, non-toxic material with good structure, porosity, aeration, drainage and moisture-holding capacity. Organic wastes are ingested by earthworms and egested as a finely divided peat-like material referred to as vermicompost. Vermicompost supplies minerals and improves nutrient availability to plants. Vermicompost is considered as a high quality horticultural compost due to its homogeneous texture, desirable characteristics, reduced levels of contaminants and tendency to hold more nutrients over a longer period, without adversely impacting the environment.
During the vermicomposting process, important plant nutrients that are present in feed material (such as nitrogen, potassium, phosphorous and calcium) are converted into forms that are much more soluble and available to plants than the parent compounds. Vermicompost has also been reported to contain biologically active substances such as plant growth regulators which stimulate seed germination, rooting and flowering. Vermicompost contains beneficial microorganisms and compounds that suppress pathogenic nematodes, bacteria, fungi and arthropod insect pests
Like composting, during the vermicomposting process pathogens and disease causing organisms are eliminated in an aerobic process, which involves the bio-oxidation and stabilization of organic material. However, unlike composting it involves the joint action of earthworms and micro-organisms and the process does not involve a thermophilic (hot) stage. Vermicomposting leads to an increased nitrogen mineralization rate and the humification processes that take place are greater and faster than during regular composting. A decrease in the carbon from fulvic acids and an increase in the percentage of carbon from humic acids are observed in vermicomposting as compared to composting.
The concept upon which the Worm Hammock is based is a revolutionary new way of earthworm composting. It addresses many of the disadvantages and limitations of existing vermicomposting systems, whilst incorporating beneficial attributes of these systems. The novel design concept and method of operation make worm farming at larger scales more feasible, both from a practical and financial point of view.
The Patent on the Worm Hammock system is based on the novel method of suspending a series of 'beds' of organic matter in flexible 'trays' or 'hammocks', in such a way as to locate them in a vertical stack and facilitate contact between the beds of organic matter that they contain.
The method of suspending the flexible trays allows the beds to be lowered through a series of positions over time. Perforations in the base of the flexible tray allow composting organisms, liquids and gases to pass between the beds of organic matter. Feedstock is added to the top
hammock over a period of time until it is full, at which time all the hammocks are lowered one position in the series, starting with the lowermost hammock. The lowermost hammock is detached from the system to allow harvesting of the mature vermicompost. Once emptied, this hammock is returned to the uppermost position in the series and new feedstock is added to it.
|Contour Landscaping, Diepsloot, Johannesburg||Amathole Berries, Stutterheim, Eastern Cape|
This design and method of operation of the system is particularly advantageous from both a material handling and scale point of view. Operating the system requires little effort and causes minimal disturbance of the vermicomposting ecology. As with other continuous flow
systems, efficient processing can be maintained on an ongoing basis and minimal effort is requites. While existing continuous flow systems are costly and make use of high-tech materials and engineering, the current embodiment of the Patent has purposely been designed 'low tech' to make it as accessible as possible. The Worm Hammock has been designed with simplicity and ease of use in mind, making it 'appropriate technology' that can even be built and operated in rural areas of the developing world. The simplicity of the system means that there is far less chance of blockage or mechanical failure and the level of technology required to build and maintain the system is quite basic.
While the scale of the Worm Hammock is generous (between 50 and 60 'home' worm farms fit into one unit) it is designed to be modular, with large-scale multi-unit installations in mind.
Each Worm Hammock unit contains over a tonne of material (3 layers or 'hammocks', with over 350kg per hammock). The surface area of the material in the uppermost layer is around 8 square meters, offering a large uninterrupted area for the vermicomposting process. In the
current embodiment of the Patent, the Worm Hammock is designed to be people scale for ease of working, but the design is flexible enough that it can either be human-powered or mechanized, depending on the context in which it is being used.
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