Tiger worms attack cow effluent

Papawai Ltd directors Dallas Lucas and Peter Donnelly are using tiger worms to deal with their cow effluent, the first farm-based operation of its kind in New Zealand. Mr Lucas told visitors to his farm from the NZ Large Herds conference last week they had inherited an effluent system that was unsustainable in the long term. They had explored many options while researching a replacement effluent system but were unconvinced about holding ponds, he said. They did not want to install a 3.6 million-litre pond to meet the requirements of having 90 days' storage – a 2m-deep pond with a surface area of 1500m2 would have been needed – and wanted a simpler, more slimlined option, Mr Lucas said. They milk 550 cows on 213ha but are keen to expand to 750 reports The Southland Times. It was decided a 150m2 BioFiltro worm farm with a weeping wall would work well for them, even though Mr Lucas admitted it was "bit of a punt". "We went to the worm farm for environmental reasons, as well as taking out the labour and `risk of spill' elements." The system produces no odour and will mitigate the potential environmental effects of untreated effluent ending up on the land if an irrigator malfunctions. BioFiltro director Max Parkin said the treatment system was developed in Chile, where it was dealing with human effluent from a town of 12,500 people, as well as waste from a meat processor, and waste from a cheese factory. The effluent is filtered through a Clean Green weeping wall with the drawn-off wastewater sprayed – up to 40,000 litres a day – on to a bed of sawdust, humus and rocks, where aerobic and anaerobic bacteria and worms tackle it. The liquid produced is treated with ultraviolet light to kill any remaining bacteria.