Thursday, September 26, 2013
What Won't We Think of Next?
Devices, like the one pictured above, are catching on in our water-scarce world. It's a combination, sink-toilet. Waste water from the sink is used for toilet flushing. Makes perfect sense. There's even a fashionable sink-urinal on the market.
As protracted drought becomes a reality in many parts of the world, attention is inevitably drawn to waste water recycling.
As water supplies fall, many regions are using urban wastewater, a very valuable resource if it is treated properly, says the study “Global, regional, and country level need for data on wastewater generation, treatment, and use”, published Sep. 5 in the journal Agricultural Water Management.
This is the first study to look at how wastewater is used in 181 countries. One of the key findings is that only 55 countries have good data. Synthesising what data there are, researchers found that high-income countries treat 70 percent of their wastewater while middle-income countries treat 28 to 38 percent. Just eight percent of wastewater generated in low-income countries undergoes any kind of treatment.
“Water-scarce regions can’t grow enough food to feed their own people,” said co-author Manzoor Qadir of United Nations University’s Canadian-based Institute for Water, Environment and Health (UNU-INWEH).
“From the earliest of times, most wastewater has truly been wasted. However, it is a vast resource if we reclaim it properly, which includes the separation of municipal from industrial wastewater,” said UNU-INWEH Director Zafar Adeel.
Wastewater is valuable because it has very high level of nutrients, including potash, nitrogen and phosphorus, eliminating the need and cost of fertilisers. However, untreated wastewater can transmit diseases such as cholera. Chile experienced cholera outbreaks and banned the use of untreated wastewater in 1992.
Regions that face the threat of successive drought and flood cycles, including parts of Canada, will need to find ways of collecting and storing floodwaters. Climate change is bringing major shifts in precipitation patterns. Farmers may get inundated when they don't need it and no rainfall when they do.