On nitrogen recycling.

 To reduce input of reactive nitrogen to the biosphere improved use of the nitrogen in our waste flows could be important. What do we know?

 Sewage sludge: contains only a small fraction of the total sewage nitrogen flow.

Waste water irrigation. Discussed as a necessity/possibility in some parts of the world. But considering our discussion about impurities and risks with sewage sludge a largescale development does not seem likely.

Re-capture of the nitrogen in sewage works. Norsk Hydro had a practical process in one of the sewage works of Oslo. Driving off ammonia and capturing it in acid to ammonium nitrate solution. Worked commercially in limited scale. Another possibility which has been proposed is precipitation of magnesiumammonium phosphate (struvite). It captures phosphate and some nitrogen. In a new situation such processes can be further developed.

Separation of urine and faeces, use of urine as fertilizer. Takes care of most of the nitrogen. But there is a storage- and transport problem, especially for large cities. But definitely a possible part of a future system.

Composting. Compost has a good reputation but is a process wasting nitrogen.

For developing countries there are developments like Pee-Poo bag.

However, there is another principle, not unlike our present system: we transform the reactive waste nitrogen to unreactive gas and fetch it back in an ammonia factory. Then the nitrogen issue is transformed to an energy issue.

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One Response to “On nitrogen recycling.”

  1. Angila Warnasch Says:

    Needless to say, what good website also to informative posts, I will add backlink – bookmark this web page? Regards, Reader.

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