Healthy soil and sustainable growing

[Kate Spinner <kespinner@gmail.com>]

to get to the point read #8

http://phosphorusfutures.net/why-phosphorus

I'd rather pee in a separate place (a.k.a bucket or whatever) than see entire watersheds ripped up by mining:

and another question - are there any other elements, aside from phosphate, that we mine for that are readily available in nature without mining? 

8. Recirculating human excreta

Human excreta (urine and faeces) are renewable and readily available sources of phosphorus. Urine is essentially sterile and contains plant-available nutrients (P,N,K) in the correct ratio. Treatment and reuse is very simple and the World Health Organisation has published 'guidelines for the safe use of wastewater, excreta and greywater'.^19,20,21

More that 50% of the worlds’ population are now living in urban centres, and in the next 50 years 90% of the new population are expected toreside in urban slums. Urine is the largest single source of P emerging fromhuman settlements. ^22,23

According to some studies in Sweden and Zimbabwe, the nutrients in one person's urine are sufficient to produce 50-100% of the food requirements for another person. Combined with other organic sources like manure and food waste, the phosphorus value in urine and faeces can essentially replace the demand for phosphate rock. In 2000, the global population produced 3 million tonnes of phosphorus from urine and faeces alone.^21,24,25

Unlike phosphate rock, which only exists in a handful of countries' control, urine and faeces are available from any community or city,and hence can contribute to 'phosphorus sovereignty' and food security.⁸

In material flow terms, human excreta represents a readily available 'exchange pool' of phosphorus, before it is 'lost' to the hydrosphere typically as treated or untreated effluent discharged to rivers and oceans. If urine is reused as a fertilizer, then less phosphorus (in urine) is entering waterways, reducing the potential to cause toxic algal blooms.¹¹

Although preventing phosphorus point sources from entering water bodies is often necessary to prevent water pollution, removing high levels of phosphorus at the wastewater treatment plant is expensive and energy intensive. Capturing urine at source (at the toilet) can be much more energy efficient and cost-effective and does not contain heavy metals like Cadmium.^11,26

The cost of ecological sanitation systems around the world could be offset by the commercial value of the phosphorus (and nitrogen) they yield in the future. Particularly in Africa where synthetic fertilizers typically cost 2-5 times more than in Europe. A community ecological sanitation toilet in Tamilnadu, India, now pays users, recognising the fertilizer value of their urine and faeces.^27,28,29

On Jul 14, 2010, at 8:17 AM, <pbunch@cox.net> wrote:

http://www.slate.com/id/2258112/entry/2258053/
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