General Sewage Technology

Decentralised wastewater treatment and urine separation

New sanitation technologies facilitate separate urine collection by means of NoMix toilets. This allows separation of the nutrients to a separate wastewater flow and thus relieves the load on sewage plants. In addition, urine separation facilitates recovery of the nutrients contained for use as agricultural fertiliser. The project partners demonstrate the successful decentralised treatment of the wastewater flows.

Summary


Besides the opportunities for water recovery, the implementation of decentralised wastewater treatment also offers the benefit that treatment can be adjusted to the specific wastewater quality on site.
The project participants research use of the new sanitation technology for separate collection of urine. NoMix toilets and waterless urinals are used in an office building and their suitability and acceptance are evaluated. The wastewater is treated in three separate reactors. The greywater and the brownwater are each treated in a separate membrane bioreactor. A further reactor is used to recover the phosphor from the collected urine by means of MAP (magnesium-ammonium-phosphate) precipitation. The product of the MAP precipitation can be used as agricultural fertiliser together with the urine.

Results:

  • Further optimisations are necessary for the NoMix toilets.
  • The problem of unpleasant odours was resolved satisfactorily. This was achieved by means of an encapsulated system design and a good ventilation system.
  • With technical magnesium oxide, phosphor recovery reached 67%, which corresponds to a yield of 0.7 to 1.3 g MAP l-1 urine.
  • MAP precipitation cannot currently be implemented profitably due to the long dwell times.
  • Introduction of pharmaceuticals to the environment can be largely discounted when using MAP in agriculture. Using urine as fertiliser is also hygienically safe.
  • The MAP product's fertilising effect can be regarded as competitive in comparison with commercial fertilisers.
  • After treatment in the membrane bioreactors, the water quality is suitable for use as service water and for toilet flushing.
  • Decentralised wastewater treatment is technically feasible. Under the right boundary conditions, it is also economically viable.

More Project Information

Project title: SANItärRecycling ESCHborn (SANIRESCH)

Project number: 02WD0947-52

Project period: 2009 - 2012

Project region: Germany (Hesse)

Project contact::

Frau Dr.-Ing. Winker
This email address is being protected from spambots. You need JavaScript enabled to view it.
+49 (0) 69 707 69 19-53
+49 (0) 69 707 69 19-11

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Source: German National Library of Science and Technology Hannover (TIB)