RECOGNISING WASTEWATER AS A RESOURCE
As its name implies, wastewater is grossly undervalued as a potential resource. All too frequently wastewater is ignored and left to drain away. Smart and sustained investment in wastewater management will generate multiple dividends in society, the economy and the environment. It can involve both private and public sectors, fulfilling public needs as well as social equity and enhance food security. Immediate, targeted and sustained in- vestments should take multiple forms. They should be designed to (i) reduce the volume and extent of water pollution through preventative practices; (ii) capture water once it has been polluted; (iii) treat polluted water using appropriate technologies and techniques for return to the environment; (iv) where feasible safely reuse and recycle wastewater thereby conserving water and nutrients; and (v) provide a platform for the development of new and innovative technologies and management practices. If investments such as these are scaled up appropriately they will generate social, economic and environmental dividends far exceeding original investments for years to come.
It is acknowledged that water is a limited resource for which demand is growing. Managing wastewater is intrinsically linked to management of the entire water chain. How we use and reuse water is the key to successfully meeting the vast water requirements of an urban population twice its cur- rent size, expanding agriculture to feed another three billion people and satisfy rising demand for meat, while coping with increasing food waste.
Climate, geography and healthy ecosystems together control the initial supply of water in the water chain, maintain water quality and regulate water flow. Forests and wetlands, includ- ing salt marsh and mangrove forests, have an important natu- ral role to play in wastewater management, capturing water, filtering out nutrients and other contaminants and releasing water into lakes, rivers and coastal seas. Worldwide, these eco- systems are being lost and with them the services they provide for buffering extreme weather and assimilating wastewater.
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Developing strategies to improve environmental governance, including improving watershed, coastal and riparian manage- ment, irrigation efficiency and the greening of agricultural practices, provides an enormous opportunity for maximizing the benefit derived from natural ecosystem processes, greatly reducing the negative impacts of wastewater, and increasing the availability of water to cities.
Climate conditions and watershed management, particularly with regard to deforestation, cropland development and inland aquaculture, are crucial factors in determining the quantity and quality of the water which will eventually be available for irrigation in food production, processing in industry, human consumption and recycling.
Worldwide, water tables and aquifers are declining (IWMI, 2006). With climate change, rainfall patterns are likely to be- come more variable and extreme rainfall events more frequent.
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