Grant to purify wastewater

The Biotechnology Research Centre at La Trobe University, Bendigo has started a three-year project to develop and evaluate a new process to purify wastewater.

Professor Bob Seviour has received a $230,000 Australian Research Council grant over three years to develop a microbiological process to remove phosphorus, a major pollutant which causes blue-green algae and other problems, from rivers and lakes.

Existing methods of removing phosphorus require costly and complex plants which usually use chemical processes, most of which are unpredictable and unreliable.

These processes are based on cycling the 'biomass' - the polluted water - through alternate anaerobic and aerobic reactor zones.

"If we can develop a fully aerobic system, capable of being added onto the end of a conventional treatment plant, it would make protection of rivers and streams more feasible and cheaper," Professor Seviour says.

Professor Seviour is developing an aerobic system conceived, in principle, by Professor Ron Bayly and Dr John May, formerly of Monash University. Now retired, both men will act as unpaid consultants to the project, to help with experimental design and data analyses.

Their aerobic process, says Professor Seviour, is 'revolutionarily different' from conventional 'enhanced biological phosphate removal' (EBPR) systems because it is carried out in a single reactor.

In this new system, selective pressures on microbes are applied in a totally different way than in conventional systems, which have been operating for three decades. Laboratory tests show that, with effluent from a conventional treatment plant, the process reduces phosphate concentration to a level which will not allow algal blooms to develop in receiving bodies of water into which the treated water is discharged.

Professor Seviour is seeking to understand the structure and function of the microbial communities selected under aerobic conditions to determine which are the polyphosphate accumulating organisms, and so provide a rational basis for monitoring and controlling wastewater plants.

"We will scale up this process to pilot plant operation, allowing its performance to be assessed in treating effluent from a full-scale conventional activated sludge plant," he says.

Professor Seviour believes the project will lead to a process with the potential for a wide range of phosphorus removal, cheaper and more flexible than systems now available.