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| Dr Martin Anda
| a new basis for urban sustainability in the decade of education for sustainable development

Martin Anda has been associated with the ETC at Murdoch University for almost 15 years. He took over as Director in 2005 after a four year period as Research Manager and is now the new Chair of Environmental Engineering at Murdoch University's School of Environmental Science. Martin's focus is on industry-funded research, commercial consultancy and remote area sustainability. Martin heads a major project funded through the Cooperative Research Centre in Desert Knowledge and also is active in the Remote Area Developments Group (see the RADG website). Martin has developed a series of innovative relationships with industry partners (incl. Little Creatures Brewery, National Lifestyle Villages, Aussie Outback Lodges) and government and regulatory authorities (incl. Water Corp, Office of Science & Innovation, various Local Government Authorities).

Below Martin raises some points that urban centres, like Perth, will need to consider, with urgency:

Sustainability in an urban settlement can be created and assessed across 4 essential resource flows:

• Water
• Energy
• Food
• Materials

The population of Perth is set to double in the next 30 years. Accordingly serious attention needs to be given to the above resource flows if a high quality of life is to be sustained for all these people, for that duration and beyond. This presents the opportunity for a new way forward in urban sustainability.

Water Now
Perth’s rainfall has declined by 15% in the last 20 years leading to a reduction of 50% of runoff into the Darling Scarp catchment dams. Under even the most conservative climate modeling scenarios rainfall in the southwest will continue to decline.

The current business-as-usual approach to urban development and renewal will lead to severe water supply restrictions within 10 years – restrictions beyond mere part-time sprinkler bans.

Energy Now
At current rates of consumption, which is rapidly increasing anyway, the world’s economically exploitable oil will be exhausted in 50 years, gas in 100 years and coal in 200 years. A shift to coal-derived oil and gas can occur but nevertheless the global CO2 emissions will continue to rise and climate change is forecast to deliver increasingly catastrophic temperature and storm events over the next 30 years.

Untamed urban sprawl with no local economic opportunities will continue to deliver increasing traffic flows with congestion and air pollution.

Increasing fossil fuel prices will render current modes of daily intra urban commuting over large distances economically unviable.

Food Now
The world’s supply of phosphorus used for the manufacture of chemical fertilizers to grow food by industrialized agriculture will be depleted within 50 years. As has occurred in previous civilizations which collapsed due to over-exploitation of their forests and soils Australia too has created desolate and salinised landscapes for agriculture.

In the meantime, vast quantities of P and other nutrients essential for plant growth are disposed of to the environment via sewage to ocean outfalls, and

Organic materials valuable for soil-building in our solid wastes are sent to landfill and incinerators.

Materials Now
The global construction and demolition sector contributes over 40% of the world’s greenhouse gas emissions. This is for the total lifecycle of a building: the sourcing of materials, manufacture of components, construction, occupancy, demolition and disposal. For sourcing the materials forests are felled and new quarries opened for more raw materials, the ocean floor is dredged for lime to make cement.

In the meantime, over 50% by mass of waste to landfill is construction and demolition waste.

The ancient Greeks developed solar architecture and planned whole cities in Greece and Asia Minor such as Priene by Hippodamus of Miletus, to allow every homeowner access to sunlight during winter to warm their homes. By running the streets in a checkerboard pattern east-west and north-south, every home could face south, permitting the winter sun to flow into the house throughout the day. Nevertheless, the Ancient Greeks had their own "energy crisis". They used all of the wood surrounding their cities and did not plan ahead by planting more trees. They had to get wood from far away sources. Even now modern planners pay scant regard to solar design yet this is just the first step to a sustainable urban settlement.

To achieve a truly viable form of urban development the following measures need to be taken to restore balance and achieve sustainable resource flows into the future:

Water
An urban village can reduce its dependence on externally supplied water from current rates of consumption by up to 70%. This can be achieved through investment in demand management water efficiency practices and technologies, diversified water supply and reuse infrastructure, fit-for-purpose uses and pricing. This, in brief, is the Integrated Urban Water Management model.

• All homes and commercial premises are fitted with state-of-the-art water efficient appliances.
• All landscapes are of water sensitive design and dripline irrigation with soil moisture and rain sensor controls.
• Local native species are selected where food production is not the focus.

Water supply infrastructure is a mix of decentralized rainwater tanks (integrated into buildings for thermal mass) plumbed to internal non-potable uses (potable use by choice); stormwater infiltration/ recharge to local aquifers for irrigation and solar-powered reverse osmosis filtration for other uses (membrane technology is becoming cheaper); scheme supply by an external provider is reserved for potable uses only.

The solids from sewage effluent are intercepted by localized biofilters and the secondary effluent treated by constructed wetlands as municipal landscape features to supply park irrigation needs and urban agriculture. This secondary effluent is also reused in homes via third pipes after village-scale membrane bioreactors. Urine separating toilets are used to harvest 50% of P and 80% of N to be used in urban agriculture. Biosolids from the sewage filters are anaerobically digested (along with other organic waste streams) to generate methane for energy production and then vermicomposted at several depots for urban agriculture.

Energy
Perth’s current average household energy use is 20-25 kWh/day. This can be reduced dramatically.

• Domestic energy use as little as 5 kWh/day can be achieved by building nodal urban villages with passive and active solar architecture and sustainable construction techniques.
• With this infrastructure in place to reduce energy demands all year round in Perth’s moderate climate it is then possible to meet most needs by means of renewable sources. While solar photovoltaic panels are currently expensive energy generators at about 30 c/kWh compared with coal at 4 c/kWh efficiencies are set to increase and amorphous silicon building integrated photovoltaics (BIPV) may become the large scale distributed energy source.
• BIPV can be mandated across the village for daytime generation. Such dark metallic rooftops will also act as solar collectors, water heaters and water catchment areas to raintanks.
• The urban villages will be variously located at high points above the coast and hillside slopes and will be separated by urban greenways where the original vegetation can be conserved (interspersed with urban agriculture) and hilltops will be populated by wind turbines with generous buffer zones for noise abatement and nature conservation.
• Non-recyclable solid wastes not reprocessed by composting/vermicomposting will be sent to large municipal scale anaerobic digestors for the production of methane to generate electricity via regional base load gas turbines (LNG as backup).
• Local solar hydrogen bus services, pathways, cycleways to light rail terminals connected to the major rail stations will massively reduce private motor vehicle dependency.
• Biodiesel pool vehicles will run as private enterprise in each urban village.

Food
In the advanced industrial countries people consume 125 GJ food each year. Only 5 GJ of this is actual food energy consumed. The rest is the energy intensive industrial agriculture, processing, manufacturing, packaging, transport, storage and retail.

• Urban organic agriculture will provide a significant source of local food production.
• This form of agriculture in the valley floors of urban greenways will use the water and nutrients recycled from the city’s wastewaters and the soil will be improved with reprocessed organic wastes and biomass harvested from plantations.
• Food production areas will be an attractive landscape feature as in Tuscany, Israel and island cultures.
• Local enterprises are built around the value-adding processes after the harvests.

Materials
Zero waste to landfill must be the target of any community seeking sustainability.

• The solid recyclable glass, metal, paper and organic fractions are easily recovered through municipal and private sector programs.
• Much of the rest is building and demolition wastes which can be reprocessed into new building materials. This stream can supply much of masonry needs for rammed earth walling, recycled concrete floors.
• Low embodied energy materials such as plantation timber and cork, recycled plastic paneling, recycled tyre flooring, as well as industrial wastes for new building materials and photovoltaic glazing for windows provide the rest of the built form.
• Urban forestry can be started now to ultimately weave its way through the urban greenways irrigated with reclaimed water. This will be the timber supplies for future construction and act as a carbon sink and an enterprise of carbon trading.
• As land sales proceed developer, government and community trusts can invest in plantations further afield as more sinks for their CO2 and more supply of timber.

The above are only some of the less complex environmental technology systems that need to be integrated across the urban form. The greater challenge is to create the associated social and economic capital necessary to operate and maintain these systems. And this planning must commence also.

» contact Dr Martin Anda