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Posts Tagged ‘sewage’

Putting poo safely into the right place–the fields!

In a contribution to the Agriculture and Ecosystems Blog, Fred Pearce describes our current practices of dealing with human excrements – mainly the discharge of waste water from urban centers to water bodies – as “one of the modern world’s worst, but least discussed, resource failures”. Given the high contents of nutrients in sewage and the negative impacts their discharge unfolds on ecosystems he may be absolutely right.

And he rightly emphasizes that there is a big potential in the better use of waste waters, but not without mentioning the potential risks to public health involved. And while recognizing that the informal collection and subsequent use of sewage in agricultural production is a reality in many places of the developing world, he criticizes that policy makers and researchers alike either prefer not to deal with the issue or tend to contain the practice. Instead they should recognize the potential, but without losing the need for proper regulation and for the use of adequate technologies out of sight.

The question is, of course, whether this will happen. It seems that a necessary condition is that obtaining the resources embodied in waste water from alternative sources of supply becomes more expensive than water treatment and associated activities (e.g. setting up an adequate institutional framework and the like). Pearce mentions the examples of countries located in arid regions like Israel, Mexico and Tunisia where waste water is getting recycled. Rising energy prices may also contribute, directly and indirectly through higher costs for synthetic nitrogen fertilizers. Or increasing scarcity of phosphate rock (see, for example, a paper by Cordell et al.) may lead to higher prices for phosphorus fertilizer and contribute to new thinking in that area.