"Wiggley worms do their stuff" in dealing with Ummera's solid waste in an environmentally-friendly way

The solid waste generated during our production is principally fish heads, fish skeletons and offal. Awareness of the difficulties created by waste, especially fish waste, started Ummera searching for alternative methods to achieve a healthy and environmentally sound way of handling these wastes.

Mike Lynch of the Irish Earthworm Company installed a vermicomposting unit in April 2000. This unit proved itself over the first summer as we gradually introduced fish waste to the worms. By November/December the worms were very happy with their new diet. In the six weeks up to Christmas nearly a tonne of waste was fed to the worms. A fair test. As a result we have now installed a larger and more efficient system.

What is Vermicomposting?
Vermicomposting is much more complex than worms simply ingesting and excreting organic material.

Vermicomposting involves utilising worm colonies that work on two levels:

1. Worms are primary consumers of organic material.
2. Worms also create conditions that promote beneficial aerobic bacteria and optimal composting conditions.

System Description
A block built unit was constructed measuring 32 ft x 4 ft with a surface area of 128 sq. ft. with secure fitting plywood lids.

A land drainpipe was placed down the center of the unit to aid aeration.

Bedding was then added to the unit. This bedding serves two purposes;
1. It is the worm's accommodation.
2. The mix used in the bedding can be manipulated depending on the specific organic material to be processed e.g. fish offal has a high nitrogen content so the bedding utilised in this system contains lots of shredded cardboard, which has a high carbon content, to balance this.

How the System Works
Organic waste material is "fed" to the system on a daily or weekly basis depending on production. This waste is buried under the surface of the bedding to deter vermin and bad odours. The worms then feed on this waste and create conditions that encourage aerobic bacteria to colonise the organic material and break it down.

Once the previous feed has been broken down and incorporated into the compost another feed can be added.

A worm can consume from 50% to 100% of it's body weight every 24 hours; this fact is used to calculate the quantity of worms required to process a given amount of organic waste on a weekly basis e.g. 20kgs of worms will consume between 70-140kgs of organic material per week.

The vermicomposting process has a severe effect on levels of pathogens (up to 99%), enteric viruses and parasites.

The vermicompost harvested in this process is microbiologically active and can regenerate nutrients from the atmosphere, so re-application is not required at the same rate as chemical fertilisers. Therefore it is more valuable and produces a benefit for longer.

Vermicompost does not require curing like traditional compost as it is already populated with beneficial bacteria and can be applied to the soil immediately.