SA scientist pioneers new system for organic waste

A biotechnologist from the South Australian Research and Development Institute ( SARDI ) has demonstrated a unique ‘waste-food-chain’ with major implications for industries that produce organic waste.

One of 16 early career Australian scientists chosen to present at Fresh Science last week, Andrew Ward has applied a combination of traditional oriental and unique approaches to transform pig waste into feed for aquaculture, water for irrigation and methane for energy. Fresh Science is a federal government funded communications ‘boot-camp’ for early career scientists held at the Melbourne Museum.

The process that Ward has developed involves pig effluent being fed into an airtight two-stage digester, which breaks down the odorous chemical compounds, kills potentially dangerous bacteria all the while producing methane bio-gas. Most importantly, the resulting nutrients are then able to be used to stimulate the growth of microalgae or small seaweeds.

“Once we had the algae growing, we knew we could recreate the ocean food chain from algae to zooplankton to fish,” Ward said. Key to the process are two varieties of South Australian zooplankton, or water flea, species Moina australiensis and Daphnia carinata.

“By carefully establishing the best conditions for growth and reproduction, the water fleas can be produced more quickly than with existing methods,” Ward said. “This makes the system more efficient and the technology financially viable.”

The zooplankton also reduce the levels of nutrients and bacteria in the water in which they grow making it cleaner for the purposes of irrigation.

The overall result is that organic waste can be turned into food, saving money and water while improving the environment.

“We are hoping this research will lead to elimination of the environmental concerns and costs associated with waste disposal, and that the wastes themselves can be transformed into new and diversified business opportunities,” Ward said.

He added that similar bio-treatment treatment systems could be applied to deal with the liquid and solid waste from other industries such as poultry, feedlot cattle, aquaculture, seafood, grains, brewing and wine.

“This integrated production technique is pioneering work in Australia,” he said. “We hope it will present a shift in thinking for business where they begin to regard waste no longer as a cost, but as an income stream.”

Ward’s work is funded by the Environmental Biotechnology Cooperative Research Centre (CRC) and brings together research from Murdoch University, SARDI, The University of Adelaide and the CRC.

Other financial support is provided via the $4.3 million Commercial Scale Integrated Biosystems (IBS) Project for Organic Waste and Wastewater Treatment for the Livestock and Food processing Industries, formed in 2005 and sponsored by the SA and federal governments.