New angle on recycling

BIOLOGICAL waste will now be recycled to feed fish. A joint project has been undertaken by the University of Queensland, Australia, and state and industry researchers to process waste to feed crayfish and silver perch. The project will reduce the adverse environmental impact of waste products from the intensive livestock and food processing industries, according to a recent report in the Wall Street Journal.

Kevin Warburton, lecturer in zoology at the University of Queensland, said that the research was aimed at converting waste products to fish food through a microbial digestion process, and also would use aquaculture technology to grow crayfish and fish. "Biological waste represents a valuable nutrient resource, when subjected to microbial treatment," he said. "Microbial activity converts raw waste to useful animal feed or fertiliser."

The study would assess the economic feasibility of using treated effluents from animal farms to fertiliser aquaculture ponds, thus converting a polluting waste product to a source of high-value protein.

Dung causes significant pollution when untreated waste from dairies is discharged into lakes and rivers, and has recently been the subject of investigations by environment protection agencies. Effluents from dairy farms and livestock industry have little commercial value, and its disposal is a major problem. The project will identify techniques which could be applied to a wide range of integrated aquaculture schemes involving dairying and food-processing industries.