Introduction

All life depends on water. Our Earth, home to all species, remains the only place we know capable of sustaining life. In our search for others amongst the stars, it is water we look for first. More than 71% of the planet is covered in this resource, but only a small proportion is suitable for human use. 97.5% percent of the world’s water is salt water and of the 2.5% freshwater, nearly 70% is locked in glaciers and the ice caps. The majority of what remains is inaccessible; either as soil moisture, permafrost or deep beneath the ground. All considered, less than 0.03% of global water is viable for human use (US Geological Survey 2014). With the world’s population is rising at a rate of 80 million people a year, water demands are increasing proportionally (Worldometers no date). In order to sustain over seven billion people, we require more than 200 million litres of clean water per second (Waterwise no date). 67% of this is for agriculture, 22% for domestic, and 11% for industrial use. Our overstretched resources are very unevenly distributed. Areas with high natural resources are rarely near the urban centres of high demand and this is becoming more severe. For example the top countries for fresh water supplies, Brazil, Russia and Canada, with 30% of the world supply between them, are not areas of highest population growth, India, China and Nigeria take the top spots there (Cohen & Siu 2013).

Water Stress - An Increasing Problem

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Social and Economic Effects

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Sustainable Water Managemen>

Many studies have charted the perception and acceptance of recycled water over the years (Bruvold and Ward 1970; Bruvold 1972, 1979 and 1988, Nancarrow 2003, Dolnicar and Schäfer 2006, 2007 and 2009; Dolnicar and Hurlimann 2010; Hurlimann and Dolnicar 2010). Whilst levels of acceptance vary with time and location a few conclusions are consistently drawn:

1. In general, public knowledge on the subject of water treatment and the advantages and disadvantages of different processes is relatively low.
2. General perception of recycled water is that, whilst it is an environmentally friendly solution, there are public health concerns.
3. Recycled water is considered acceptable for tasks such as gardening and car washing. When it comes to close body use (bathing and showering) there are reservations due to fears of residual wastewater in the recycled water.
4. Perception is very dependant on the particular source and treatment of the water.
5. Choice matters: in places where alternative sources of water were available, people were more sceptical of water reuse than in regions with water shortages.

Decentralising the Water Supply

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Wastewater Recycling

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Conclusions

Our planet’s natural water resources continue to be unsustainably exploited; as a result, we are faced with the challenges of water stress and scarcity. Climate change, population growth and urbanisation fuel the worsening crisis. To avert disaster we must rethink the way we process and use our water supplies. Promisingly, solutions are emerging but significant technological and sociological issues need to be addressed. Water treatment systems are becoming decentralised which makes the system more reliable and adaptable. Supply can be better expanded to meet changing demands and systems can be more tailored to local supplies though improvements are needed to make smaller scale plants more cost effective. Recycled wastewater is becoming an increasingly important component of our water supplies, indirect reuse is common and direct reuse, whilst initially confined to irrigation, is becoming more common. Innovations are needed to improve quality and cost as well as public confidence in the process.

References