21 Aug 2008

Toilet Veggies

The Economist blogs on an IWMI report on the use of wastewater for irrigation in developing countries. Although the idea sounds yucky, it does have benefits: Veggies grown close to cities, employment for women, reduced demand for potable water, etc. Then this caught my eye:
Spreading wastewater over fields, and allowing it to leach back through the soil into local waterways, turns out to be a reasonable way to purify it. The process filters out all the organic contaminants, and much of the nitrogen and phosphates that would otherwise contribute to algal blooms and dead zones further downstream. It is certainly preferable to dumping wastewater straight into the nearest big river or lake.
Dead zones and algae blooms have been in the news recently (and here in February!), and they are growing because of high nutrient concentrations in runoff. In developed countries, the nutrient comes from fertilizer (farmers want to maximize yield); in developing countries, it comes from untreated sewage (farmers are poorer and governments spend little on water treatment).

The story also gets at the "keeping it local" theme that's more popular. As fuel costs rise, "viable" markets are shrinking. Today, we shop closer to home, buy local food and vacation nearer. Tomorrow, we'll be living closer to work -- and recycling our sewage.

Swiss Family Robinson, here we come!

Bottom Line: As costs rise (for clean water, for fuel), people find alternative substitutes and change their habits. Homo economicus is very clever at adjusting to changing relative prices and living the good life.


  1. Wastewater into groundwater is not always the great idea it seems. Think of how all those PPCP (Pharmaceuticals and Personal Care Products) get into our drinking water. Treated wastewater (to remove PPCPs) – now there’s a GREAT idea.

  2. This reminds me that it used to be that in old Tokyo, those who ran the honey bucket industry paid for the privilege of removing the solid stuff and selling it to rice farmers as fertilizer! That sh*t's valuable!

    After the Clean Water Act, though, doesn't little get into the water except when perhaps when there's a storm?

    I understand that most of the contributons to eutrophication of lakes and rivers and to dead zones is coming from ag run-off.


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