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TEVALU Exploratory project (2023)
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TEVALU Exploratory project (2023)

TEVALU : Urine recovery in territories

This project is designed to study urine recovery in territories via an innovative extraction process for use on farms, and examine how the implementation of such a structure would impact sanitation services.Separating and recovering urine at the source is of particular interest for increasing the circularity of nutrients, notably nitrogen and phosphorus since urine consists of 86% nitrogen and 60% phosphorus per person.

Context and challenges

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Separating and recovering urine at the source is of particular interest for increasing the circularity of  nutrients, notably nitrogen and phosphorus since urine consists of 86% nitrogen and 60% phosphorus  per person. On the scale of a territory like Ile-de France, human excreta represent 22% of nitrogen and  13% of phosphorus inputs by synthetic fertilisers. Moreover, producing nitrogen fertilisers consumes  a lot of fossil resources since the Haber-Bosch process uses large quantities of fossil gas.  

 

The environmental benefits of implementing urine recovery schemes in territories can be significant:

  1. Cutting back on the use of fossil resources, since producing nitrogen fertilisers relies on the Haber Bosch process, which consumes a lot of natural gas
  2. Mitigating climate change thanks to a decrease  in traditional fertiliser production and a cut-back in direct greenhouse gas emissions stemming from  treating nitrogen in treatment plants.

Goals

This project is designed to study urine recovery in territories via an innovative extraction process for  use on farms, and examine how the implementation of such a structure would impact sanitation  services. It seeks to provide responses to the challenges that arise from separating urine at the source  by evaluating:

  • The technical feasibility of producing one or several fertilisers from urine and their environmental  impact. A physico-chemical profile of the product will be drawn up to determine the potential of the  fertilisers produced and guide their uses. The operating data of the pilot production will also be used  to qualify the treatment process with regard to its environmental footprint;
  • he territorial feasibility of urine separation with regard to deposits and uses. An inventory  of product use niches will be taken for the territory in question and urine deposits will be  mapped;
  • the economic sustainability of territory-wide urine recovery for use in agriculture. The project  proposes to carry out an economic analysis that combines economic value related to environmental  amenities and positive externalities of urine recovery.
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At the end of the project, it is expected that there will be better knowledge of products made from innovative urine treatment in terms of both health and economics – and of the potential of implementing a system by analysing territorial deposits and needs, as well as through economic analysis. 

 

Progress and result

  1. The work carried out as part of the TEVALU project has made it possible to determine the optimum conditions for recovering ammonia by absorption on a gas-permeable membrane. The feasibility of extracting ammonium from real urine was confirmed by pilot tests. The pilot experiment produced a 20gN/L fertiliser solution. The experiments and modelling work demonstrate the effect of effluent characteristics (ammoniacal N : mineral C ratio) in determining pH and temperature set points, and the pre-treatment to be applied to minimise energy demand.
  2. A territorial analysis of the Toulouse metropolitan area was carried out to quantify urine deposits and potential sinks through the agricultural use of fertilisers. This analysis was carried out using a GIS-type tool. It revealed an overall balance between the nitrogen available in urine (3555 tN/year) and the nitrogen requirements of the agricultural area (3107 tN/year) of the Toulouse metropolitan area and south-west Toulouse (Labège, Sicoval).
  3. In addition, a survey of potential users showed that the acceptability of urino-fertiliser type products is good, and that two types of product are very complementary: a solid product from phosphorus precipitated in the form of struvite, and a liquid solution of ammoniacal nitrogen from the membrane process.
  4. A deployment scenario was finally developed in 4 phases: experimentation, development, massification and harmonisation. A technical mission was carried out in Zurich, Switzerland, to discuss the results and visit an experimental site where urine separation had been implemented and other treatment technologies compared with TEVALU's (EAWAG building). The environmental analysis of the system was carried out on the basis of information acquired
  5. during the operation of the processes. An attempt was also made to monetise the environmental impacts, but this is still encountering difficulties in transposing the results from a small to a large scale.

The exploratory project TEVALU has helped to strengthen working synergies between players from INRAE units with different areas of expertise. The project was presented to a number of local stakeholders, who showed a great deal of interest. One of the project's Masters trainees has been taken on at SOLAGRO, in particular to continue monitoring urine separation and recovery projects in the region.

Project sheets

Project participants

Coordination :

Mathieu Spérandio, UMR TBI, Toulouse, TRANSFORM division, mathieu.sperandio@inrae.fr

The TEVALU project involves people from different INRAE fields, research units and divisions who are interested in finding common ground between their research in order to respond to the societal and scientific challenges of tomorrow’s cities.

INRAE partners

TRANSFORM division
UMR TBICoordinators
Treating urine and nutrient recovery
ECOSOCIO division
UMR TSE-RCo-Coordinator
Environmental and water economics,Monetarisation of environmental impacts
AGROECOSYSTEM division
UMR ECOSYSPartners
Analysis of agricultural inclusion of urine in crop fertilisers
 

Non-INRAE partners

SOLAGROTerritorialisation in the circular economy and agroecology.
Analysis of the uses of products derived from urine

Modification date: 21 November 2024 | Publication date: 22 July 2021 | By: PSM