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water may be acidic, saline and may contain heavy metals. The mine water typically needs to be treated before it can be reused.
Water quality and security of supply The cost of water is strongly related to the source of water, the required water quality, and the associated treatment requirements( for both supply and discharge.)
Where water quality requirements are relatively low or where wastewater discharge costs are high, the reuse of water is likely to be more attractive.
Water quality as it relates to public health is important in considering water reuse as a supply option. Any real or even perceived threat to public health would be a fatal flaw.
The reuse of water may increase the security of supply for specific users and may therefore be attractive in these cases, even where the cost exceeds alternative supplies. Note that it is not necessarily the case that increased water reuse increases the security of supply for an overall water supply system.
Understanding the need for water reuse Key drivers affecting water reuse choices Five key considerations affect choices related to water reuse as an option for water supply and augmentation:
• Water quality and security of supply
• Water treatment technology
• Cost relative to other water supply alternatives
• Social and cultural perceptions
• Environmental considerations.
Although these are likely to be inter-related in practice, it is useful to discuss each in turn.
We will continue with each consideration in the next issue of Plumbing Africa. To obtain a full copy of the document, visit www. dwa. gov. za and search for‘ NWRS 2’. PA
Sources
1. Water re-use, an international survey of current practice, issues and needs. Editors Blanca Jimenez and Takashi Asano. IWA Publishing. 2008.
2. Integrated water resource planning for South Africa: a situation analysis 2010. Department of Water Affairs. Report No RSA 000 / 00 / 12910.
3. National Water Resources Strategy. Department of Water Affairs and Forestry, second edition, September 2013, based on NWRS 1.
Health and sanitation
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