What Are The Possibilities Of Recycling Sewage Water Into Fertilizer? We Do It With Dung. Why Not Sewage?
Right now, biosolids (which is dewatered municipal sludge) are in fact land-applied as one disposal method. But it is put only on fields that grow animal food or some such. You can not put it on human crops.
Let’s face it, you just don’t want all the medicines and diseases that are flushed down our toilets to be put DIRECTLY onto our food. It’s a recipe for a public health disaster, and it is (in part) why you can not safely eat fresh leafy produce in many parts of the world.
Further, anything that you put onto fields will eventually leach into the water supply. This is the big argument AGAINST land-applying it at all. There is a lot of attention currently at anaerobic digestion, which is a way of getting the energy content out of the sludge (in the form of hydrogen, mostly).
Safely disposing of human waste without making people sick is a surprisingly tricky thing to do, honestly.
Great question.
4 Comments
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May 10th 2010 • 21:05
by gymnosph
they just partially treat it and spray it on the fields here. with water shortage and increase in city dwellers, its going to be an increasingly valuable resource. my favourite idea is biodigestion; get methane out instead of CO2 by using anaerobic decomposition instead of aerobic, collect it for energy generation, and the solid end product has been heat treated and broken down beautifully to a good grade soil conditioner, is easy to handle and nicer safer than slurry.http://www.anaerobic-digestion.com/
May 10th 2010 • 23:05
by littlero
I heard a story on NPR not too long ago about a place that’s using a series of swamp-like fields to purify the water naturally. Only problem is that it takes quite a bit of space so it’s not good for metro areas.
May 11th 2010 • 01:05
by Life in the slow lane
Right now, biosolids (which is dewatered municipal sludge) are in fact land-applied as one disposal method. But it is put only on fields that grow animal food or some such. You can not put it on human crops.
Let’s face it, you just don’t want all the medicines and diseases that are flushed down our toilets to be put DIRECTLY onto our food. It’s a recipe for a public health disaster, and it is (in part) why you can not safely eat fresh leafy produce in many parts of the world.
Further, anything that you put onto fields will eventually leach into the water supply. This is the big argument AGAINST land-applying it at all. There is a lot of attention currently at anaerobic digestion, which is a way of getting the energy content out of the sludge (in the form of hydrogen, mostly).
Safely disposing of human waste without making people sick is a surprisingly tricky thing to do, honestly.
Great question.
May 11th 2010 • 01:05
by Rivergir
It’s been tried a long time ago. I believe the product was called “Milorganite,” and I understand it was discontinued when they found excessive amounts of toxic metal contaminants in it. [Selenium, in particular] It would be fine for flowers but growing food with milorganite was unsafe.