Environmentally sustainable sewerage systems - including toilets which separate urine from faeces, and weekly collection of hermetically sealed waste - are the way of the future, according to a University of Queensland waste treatment expert.
Ken Hartley, of the University's Advanced Wastewater Management Centre, believes sustainable waste management will ultimately become essential to meeting environmental and economic demands.
'The traditional waterborne sewerage system is coming under increasing scrutiny, with a variety of alternative approaches being proposed,' he said.
'Almost all materials entering a community or a household leave via the garbage bin or the sewer. The composition of sewage is determined by the contents of the supermarket trolley, and Australians are big consumers of nutrient-rich protein, therefore our sewage has high nutrient concentrations.'
Mr Hartley said a surge in the construction of a new generation of biological nutrient removal (BNR) plants had taken place in recent years, replacing lagoon, trickling filter and activated sludge systems.
'By the end of 1997, 29 BNR plants will be operating in Australia - 13 of them in Brisbane - with two more near commissioning,' he said.
New controls on the levels of nutrients being discharged into the environment, the availability of affordable technology, increasing public concern about environmental issues and increased population pressures all affected the way wastewater treatment systems were developed.
'In the future, waste management will be designed not only to protect the health and safety of the community and to protect the local and regional environment, but also to provide sustainability,' Mr Hartley said.
'At present, substantial percentages of nutrients (nitrogen, phosphorous and potassium) are lost to the environment. This is particularly so for nitrogen in the current generation of nitrifying/denitrifying plants and for potassium which basically passes straight through the treatment plant.
'Most nutrients in sewage are derived from body wastes, particularly urine, and it would seem eminently sensible to segregate these components at source, where they are highly concentrated.'
Mr Hartley said he could envisage an airtight household collection system in which human waste would be collected weekly for transfer to a plant producing methane and uncontaminated fertiliser.
'A return to the night-soil system of old!' he said, adding that modern night-soil treatment plants were already operating in Japan.
In Scandinavia, urine-separation toilets are available commercially and used in eco-villages.
Australia's oldest operating sewage treatment works - at Werribee in Melbourne - will be 100 years old on February 5, 1998, and now serves 1.5 million people. Of the major cities, only Sydney, Canberra and Hobart have nutrient removal plants.
'In general, the smaller authorities are proving more responsive to public concern and are taking the initiative in the introduction of new technology,' Mr Hartley said.
'Private sector involvement is increasing, but some warning bells are ringing,' he said. 'Experience with the ?Adelaide Pong' and other private sector scenarios indicates to me that large overseas water companies bring little benefit to Australia, simply exploiting local skills.'
Co-operative Research Council for Waste Management and Pollution Control staff were beginning work on sustainability and totally new approaches to sewerage were on the horizon, he said.
'One can envisage a fully self-sufficient home or neighbourhood of the future, allowing houses or communities to be set up remote from centralised services.
'Living in the country will no longer be just a dream for city dwellers. The self-sufficient home will generate electricity by wind or solar power, collect water from rainfall and atmospheric condensers, process physiological waste for energy and fertiliser, and recycle treated grey water to the garden. Satellite links will provide communications.'
For more information, contact Mr Hartley on (07) 3365 4305.
