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'Liquid gold' could be key to sustainable cities and towns


26 May 2003
Capturing 'liquid gold' with urine-separating toilets for use as nitrogen fertiliser could be one feature of ecologically-sustainable housing developments, a seminar at Southern Cross University (SCU) of international experts next Tuesday, 3 June, will be told.

The 'Water and Nutrient Cycles for a Sustainable NSW North Coast' seminar will be addressed by three leading experts in the field of waste and water management, from NSW, Queensland and New Zealand.

"The population of the NSW North Coast is expected to double over the next 20 to 40 years, while the South-East Queensland is one of the fastest growing regions of Australia," said Dr Leigh Davison, seminar organiser, and a specialist in water and waste management, from SCU's Centre for Ecotechnology.

"Now is the time to be asking the question: 'How can we ensure that future development meets people's lifestyle needs without compromising the beauty and ecological integrity of the region," Dr Davison said.

"Part of the answer may be to switch the focus from 'end-of-pipe' waste water solutions to managing issues at their source, for instance with composting toilets and urine-separating toilets."

Urine typically contributes over 80 per cent of the nitrogen in domestic waste water, but makes up only one per cent of the volume, he said. Most urine is currently pumped out to sea or into waterways. At the same time, three per cent of the world's energy consumption is dedicated to the synthesis of atmospheric nitrogen to produce fertiliser for agriculture.

"We could be saving most of that energy by returning the 'liquid gold' contained in urine to agricultural soils as fertiliser," Dr Davison said. "We would thus be ameliorating three problems: nitrogen pollution of waterways, depletion of the non-renewable fossil fuel resource, and the creation of greenhouse gases."

He recently returned from an international ecological sanitation conference in Germany and a technical tour of Sweden: the country most advanced in the world in terms of eco-sanitation.

"Hundreds of houses in Stockholm are using urine-separating toilets: the Swedes have a system where the local councils collect urine from people's homes and take it to farmers to use as fertilisers," Dr Davison said.

Urine-separating toilets are just one of a number of devices being developed in Europe and elsewhere for the recovery at source of nutrients, water, carbon and energy from the conventional domestic waste-resource stream. These technologies are collectively being referred to as ecological sanitation or ECOSAN. Dr Davison, who says Lismore is widely regarded as being the composting toilet capital of Australia, believes that the NSW Northern Rivers region could become a crucible for the development of ECOSAN and other ecotechnologies in the South East Asia/Pacific region.

Another speaker at the seminar will be Ted Gardner, Principal Scientist - Catchment Processes, with the Queensland Department of Natural Resources, and an international expert on wastewater reuse. Mr Gardner is head of an eco-house project on the Gold Coast, and will speak on 'The Healthy Home - A Step Towards Sustainable Suburbs'. He will give the results of more than three years of monitoring of the house.

The eco-house uses 30 per cent less energy than the average Queensland home, with a cash saving of about $650 a year. Its rainwater tank and greywater filtration system could make the house about 90 per cent self-sufficient in water in an average rainfall year, if state legislation allowed greywater reuse (eg in toilets and on gardens) in sewered areas.

According to modeling based on Mr Gardner's research, if all new houses on the Gold Coast had to include large rainwater tanks, an $80 million dam proposed to be built by 2011 could be deferred to at least 2025.

The other speaker at the seminar is Dr Rupert Craggs, Research Scientist with the National Institute of Water and Atmospheric Research in New Zealand, who will speak on 'The Advanced Pond System: a quantum leap in the natural management of domestic and agricultural effluents'. Dr Craggs is a specialist in the use of wastewater treatment ponds and has been developing and refining the Advanced Pond System for 12 years in California and New Zealand.

The seminar is the first public event to be organised by the SCU's new Centre for Ecotechnology. The centre will be officially opened at the start of the seminar by Professor Jenny Graham, Dean of Health and Applied Sciences.

The Centre is believed to be the first of its kind in Australia, although other researchers around Australia are working on ecological technologies. Issues addressed by the centre include waterless sanitation, natural effluent treatment systems, mop crop research, solid waste management and soil-effluent interactions. The centre is headed by Dr Davison and also involves Dr Keith Bolton and Murray Cullen. The centre's motto is 'Turning wastes into resources by closing cycles locally, visibly, elegantly'.

The seminar will be held on the morning of Tuesday, June 3, from 9am to 12.30pm, at the university's Lismore campus. For more information contact Sara Crowe in the SCU media liaison unit, Ph: 02 6620 3144.