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Peak health and the need for more sustainable urban water systems
Citation:
ASHBOLT, N. Peak health and the need for more sustainable urban water systems. Presented at World City Water Forum 2009, Incheon, SOUTH KOREA, August 18 - 21, 2009.
Impact/Purpose:
Presentation at the World City Water Forum 2009
Description:
Large centralized urban water services in developed countries like the USA still provide significant environmental impact via loss of ecological water services, energy use, loss of nutrients from agricultural production, and eutrophication issues. Current climate models predict that many regions will generally be increasingly more water stressed as well as prone to intense storm events, further exacerbating the negative effects of centralized water services. As a consequence of many interacting factors based around energy/water use and social inequity, Peak Health may have already been reached in the USA, with life expectancies equal to that of Cuba (75 years). From a global perspective, rapidly developing regions, most of which are in water scarce regions, make water-based sanitation unsustainable if not impractical. Hence there is a need to rethink how water services can be obtained for the health of developed and developing regions by lowering our environmental footprint as well as empowering individuals/communities to control their water/sanitation services in a health-promoting environment. Examples include net energy production from organic components along with nutrients returned to agriculture, particularly phosphorus that has known stores of available rock phosphate to only last 60-150 years. From a public health perspective, aging water mains and their vulnerability to intrusions by fecally-contaminated waters is a rising issue; all the more reason to consider an alternative approach to water distribution and handling of associated wastewater streams rather than rebuilding more of the same problem. Most interesting is that the single largest cause of waterborne illness identified in the US (legionellosis) is not of fecal origin, nor currently regulated in most parts of the world. Legionellosis is due to the growth of a pathogen (Legionella pneumophila), which may largely be an in-premise (building) issue rather than the distribution system per se. Hence Legionella and other similar indigenous pathogens that grow in pipe biofilms are not necessarily the responsibility of the distribution system provider. As we move to greater reliance on reclaimed waters, fit-for-purpose, the long-term ramifications of fecal and indigenous pathogen issues should be considered within a broader sustainability assessment if we are to further improve public health. A framework for a way forward is described.