An improved mechanical separator for removing live worms from worm-worked organic wastes

Abstract

Vermicomposting has the potential to convert many organic wastes into useful plant growth media. However, the rotary screens previously employed to separate worms from vermicompost often became blinded, making worm separation slow and inefficient. An improved method was required. An experimental machine employing a novel combing action to achieve separation was therefore constructed and tested. The comb-type mechanical separator was shown to be effective with vermicomposts which were well-worked and had moisture contents of 80% wet basis or less. For example, using well-worked vermicompost derived from separated cattle solids and containing approximately 5 kg of worms/m³ and with a moisture content (wet basis) of 75%, a throughput of 1·5 m³/h of vermicompost was possible, with a separation efficiency of 95%. Vermicomposting beds are sometimes maintained at moisture contents higher than 80% wet basis, and the degree of worm-working achieved can vary. Further work is therefore required to assess the performance of the comb-type separator over a wider range of conditions.