News

One of the biggest worm farms in New Zealand, have announced they are expanding their operations by establishing new windrows on a disused air strip near Kawerau.

This site will use approximately 7,500t/year of wood fibre waste plus Dissolved Air Flotation (DAF) sludge from waste ponds at the paper mill. The two products are combined in the same way as their pulp plus bio solids operations, and laid out in similar windrows. “The advantage of this new product is that it can be applied to any land or cropping ground, in plant mixes and sold as compost” says John Fell, a Director of ECOCAST. “The material is much safer than commercial compost as it is sterile and poses no Legionnaires’ Disease risk.” Strong demand is expected from dairy farmers aiming to improve soils and get better worm cultures established.

Fell and partners Michael Quintern and Tom McDowall established ECOCAST in 2007. The original site contains about 400 million Tiger and Indian Red worms and is spread over 6 ha. Approximately 11,000t /year of municipal bio solids are mixed with 7,500t/year of pulp waste from the nearby Norske Skog paper mill and laid out in windrows 110m long, 10m wide and 500mm high.

Both feedstocks have historically gone to landfill. Although NZ Health and Safety regulations dictate that unless the residual vermicast from this material meets an Aa grade requirement and cannot be used on pasture land, there is a high demand from maize growers who report improved soil, more worms and increased plant yields. Fells says he accepts these rules but also that he believes the product to be totally safe: it’s passed through worms at least five times in the windrow, he points out. Only a quarter of the original volume of material is left, about 500t per row. ECOCAST is a good example of the Industrial Symbiosis concept being developed in Kawerau where consumption and production ecosystems become closed loops, and no outputs throughout the lifecycle of a product are wasted. The idea of ‘waste’ disappears to be replaced by ‘resources’ and ‘inputs’ that can be fed into other processes.

For more information on ECOCAST contact: John Fell ph: 027 499 6656 For more information on INDUSTRIAL SYMBIOSIS KAWERU go to: www.embracechange.co.nz