The Australian Approach to Water
In general, urban water authorities in Australia have historically focused on a once-through use-and-dispose approach to water. This involved water harvest, treatment, storage, use and disposal through a system of pipes over a large area.
During the past decade it has been increasingly recognised that Australia's water resources are limited and that traditional approaches to meeting demand by expanding supply (eg. new dams) are unsustainable.
Policies have begun to focus on more efficient, sustainable and integrated use of existing resources as well as regarding wastewater as a source of water rather than a waste product.
Integrated water management encourages coordination of local, state, national and international strategies to ensure that water is used optimally and other related issues (such as greenhouse gas production) are addressed.
Current water treatment technologies allow rainwater, greywater and effluent to be cleaned and made available for more than one use, thus reducing overall requirements.
Greywater
Melbourne has faced a number of temporary water restrictions in the past and in 2005 permanent water restrictions were introduced. The State Government has set a target to reuse or recycle at least 20% of our wastewater by the year 2010. Melbournians now rate adequate water supplies as the second most important issue facing the community.
In Melbourne, nearly all used water except that used on the garden is removed from the property and termed wastewater implying that it has no value, perhaps it should actually be called wastED water! Wastewater is defined as 'the spent water of a community' in the plumbing standards.
Greywater forms a large portion of wastewater and can be either light grey water from the shower, bathroom sink and laundry, or dark grey water from the kitchen. It is estimated that an average household produces 430L - 567L a day of greywater. Legally, recycled and reused greywater can be used for different purposes ranging from landscape or agricultural irrigation, to industrial and domestic use, this could reduce the use of high quality drinking water for purposes which do not need it.
The suitability of greywater for these uses is determined by State Government regulation and depends on the treatment that the greywater undergoes. The importance of greywater on-site reuse and recycling systems was identified in the Victorian Water Action Plan and by the introduction of rebates for EPA approved permanent on-site greywater ‘tank systems’ in 2003. The rebate amount for both treated greywater systems and permanent diversion systems is $500.
Some new housing developments in Melbourne have a third pipeline system (the VicUrban Aurora, Officer, and Fairfield developments for example) which brings recycled water to the properties from large scale treatment plants. The prohibitive cost of new infrastructure makes this type of solution in developed suburbs of Melbourne unsuitable. In our opinion private domestic on-site reuse or recycling systems are a better option in well established areas.
Greywater ‘reuse’ systems collect and then use non-treated greywater for acceptable purposes, such as irrigation. Greywater ‘recycling’ systems collect water and then treat it to a standard fit for its intended use, such as toilet flushing. The individual cost of installing a system depends on the type and size of the system installed. As a rough guide greywater diversion systems that do not treat the water cost around $1250 installed while those that do treat the water cost from around $12,500.
Water reuse and recycling is now seen to be a logical and necessary inclusion in an integrated water management program. Environmental and long term financial savings have been identified as the benefits of reuse and recycling water.
Despite the fact that in most places in europe, USA, Singapore and Israel wastewater is recycled for drinking water there seems to be both government and private opposition to any water recycling projects in Australia. There are several factors which may explain this.
First is costs - the cost of the recycled water could be higher than the cost of non-recycled water. However there are many people who have pointed out that we do not actually pay the 'true' cost for our drinking water. The cost of the infrastructure to treat the water is also very high. We expect that as the technology evolves that the cost of this should decrease and the cost per unit treated will also come down. As the government has already announced that water prices will increase in the future the difference between the cost of treated water and virgin water will also be reduced.
Secondly, is the resistance of the individual and community that feel that the water is somehow dirty or unclean. In general this idea is encouraged by the mass media coverage of the issue and the proliferation of poor information.
The third is the complexity of government and intergovernmental regulation and the proliferation of 'guidelines'.
Lastly there is a lack of good knowledge in related professions which the general public would usually turn to for guidance. these related industries include landscape architecture, garden designers, irrigation designers, architects, builders, plumbers and associated contractors.
At Botanical Traditions we believe that greywater should be considered as an alternative source of water and should form an important part of any water conservation plan. We take an integrated approach to water conservation.
If you need help developing a water conservation plan for your organisation please contact us.