Viruses help clean up wastewater

Posted on December 6, 2011

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Researcher tackles foam and bubble troubles that bedevil water authorities –

PHD science student Zoe Dyson, right, and Honours student Teagan Brown who gathered specimens, conducted lab tests and analysed data for the project.

Research results by a La Trobe University microbiologist are being trialled by three of Australia’s largest water authorities.

The aim is to decrease the impact treated sewage has on the environment and human health and improve the recycling of urban and industrial waste water.

The $420,000 project is based on work by Dr Daniel Tillett, a senior lecturer in the University’s School of Pharmacy and Applied Science.

It is supported by an Australian Research Council linkage grant announced in November by Science and Innovation Minister, Senator Kim Carr.

Dr Tillett is a specialist in genomics, bioinformatics and DNA sequencing. He says the system, developed in his Bendigo-based laboratory over the past three years, aims to recreate the right balance between ‘good’ and ‘bad’ bacteria in wastewater treatment plants by using natural ‘bacteriophages’ –  viruses that are predators of bacteria, but harmless to other organisms.

Health and pollution problems

‘The aim is to prevent troublesome foaming, a common problem at sewage and wastewater treatment plants throughout Australia. For example, one problem with foam is it can escape the plant and wash up on beaches where there is ocean outfall from sewage plants.’

Waste water sludge treatment plant

Foaming is caused by a build up of ‘bad’ bacteria which Dr Tillett’s research has shown can be kept in check by these ‘bacteriophages’. Foam is not only unsightly, but can be dangerous and difficult to remove. ‘We’ve had some foam samples survive in our lab for years,’ he says.

One of the dangers of foam comes from the harmful bacteria trapped in the foam bubbles. ‘These bacteria can damage the environment and infect animals and humans. Occasionally they can cause some very serious infections that are very difficult to treat.’

Dr Tillett says because wastewater treatment relies on settlement ponding, surface foaming creates significant and costly problems for the industry.

‘It can also be a safety issue as it makes it hazardous for workers who have to move around the plant because they can’t see where they are going and it can make walkways very slippery.’

Balancing ‘good’ bacteria

From a biological point of view, Dr Tillett says sewage and wastewater treatment processes are just another ecosystem which, to work effectively, have to remain in balance. 

Dr Tillett

‘You can regard the bacteria that lead to foaming as ‘weeds’ in that they have overgrown their ecosystem.’ So his research has identified bacteria phages that can act like ‘insects’ that specifically attack the ‘weed’ bacteria, keeping them in check and leaving the ‘good’ bacteria to treat the waste safely.

Dr Tillett says the process is not introducing any new organisms or genetically modified viruses into the waste stream as the phages are all natural isolates. 

The project is being carried out in association with the University of Melbourne, Melbourne Water Corporation, South Australian Water Corporation, and the Water Corporation of Western Australia.

Dr Tillett’s research continues internationally recognised work into waste water at La Trobe’s former Biotechnology Research Centre by Professor of Microbiology, Bob Seviour, who retired last year, and Dr Steve Petrovski. (ER)