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  • WATER2RETURN: Circular economy in the meat industry

WATER2RETURN: Circular economy in the meat industry


  • Amounts of wastewater containing relevant nutrients
  • Around 750.000 m3 of wastewater are produced per year in slaughterhouses
  • Large quantities of wastewater and wastes are emitted to the environment

Resources recovery is a very important topic nowadays, and the demand of nutrients’ sources continuously grows. The EU slaughtering sector, characterised by its high water and energy consumption, produces large amounts of wastewater, containing relevant nutrients that are daily discarded.

Around 750.000 m3 of wastewater are produced per year in pigs, cattle and poultry slaughterhouses, that all together constitute 98% of the EU slaughtering sector, what represents a huge nutrients’ source. However, ununderstandably, the current approach with regards to their treatment does not go in the direction of nutrients’ recovery and recycling, but nutrient’s removal.

In consequence, large quantities of wastewater and wastes are emitted to the environment with a great content of easily methanisable organic matter and nutrients, potentially transformable into energy, fertilising and biostimulant products, but environmentally dangerous if discharged with no treatment (e.g. leading to eutrophication, soils and groundwaters’ contamination, greenhouse gases emissions).

On the other hand, there is another growing sector experiencing an unstoppable increasechemical fertilisers (containing mainly nitrogen, phosphorous and potassium), whose consumption has reached around 13.6 million tonnes by 2012, and whose extensive use generates an environmental problem in Europe, as they reach water bodies, that get polluted. 

So…what if we make use of industrial symbiosis, turning wastewater treatment facilities like those installed in slaughterhouses into nutrients’ bio-refineries?

Water2REturn then constitute a real technological breakthrough based on a Circular Economy approach, in which treating slaughterhouses’ wastewaters would facilitate the recovery of nutrients with high market value.

Under a Circular Economy modelvaluable biological nutrients would be injected into a truly circular path consisting of material reuse, extraction of biochemicals and commodity feedstocks, extraction of nutrients and soil improvers (through composting and anaerobic digestion), and extraction of energy (through anaerobic digestion and other waste-to-energy technologies), valorising biomass optimally this way.

The extracted nutrients can be injected back into the economy as new raw materials, that become a resource and not a waste anymore, thus extracting the maximum value from slaughterhouse wastes, increasing the security of supply and avoiding landfilling/emissions.

Moreover, additional benefits are the promotion of synergies among key industrial sectors (e.g. agriculture, food processing and water treatment), the maximisation of land use efficiency, the decrease of food production’ environmental impacts and the increase of recycling companies’ competitiveness by obtaining revenues from byproducts with a potential value in the market as fertilisers.

Water2REturn proposes a full-scale demonstration process in cascade for integrated nutrients recovery from the slaughterhouse industry’s wastewater using biochemical and physical technologies and a positive balance in energy footprint.

The project will not only produce a nitrates and phosphate’s concentrate ready to be used as organic fertiliser in agriculture, it will also use an innovative fermentative process designed for sludge valorisation which results in a hydrolysed sludge (with a multiplied bio-methane potential) and biostimultant products, with low development costs and high added value in plant nutrition and agriculture.

This process is complemented by proven technologies such as biological aeration systems, membrane technologies, anaerobic processes for bio-methane production and algal technologies, all combined in a zero-waste-emission and an integrated monitoring control tool that will improve the quality of data on nutrient flows.

Thus, the project outcomes will be one integrated system to treat wastewater and three agronomic products free of pathogens and pollutants ready to be commercialised (one fertiliser and two biostimulants).


  • Development of a demonstrative application for slaughterhouse wastewater treatment and large-scale nutrient recovery in a real case study, the slaughterhouse of Matadero del Sur in Seville (Spain).

  • Production of organic-source fertilisers and biostimulants (Nitrates concentrate, Bacillus spp. and microalgae).

  • Reduction of the adverse effects of nutrient emissions on the environment: recovery rates of 90-95 % nutrients (N and P), with the consequent reduction in the contamination of water bodies for nutrient excess (i.e.eutrophication).

  • Reduction of wastewater discharged to the environment by 90%, producing nitrates concentrate and high quality reclaimed water guaranteeing complying standards for water recycling in other activities (e.g. cleaning or irrigation), reducing operational costs of the slaughterhouse.

  • Reduction of waste diverted to landfill by 80%.

  • Energy self-sufficiency of slaughterhouses wastewater treatment plants.


  • Production of empirical evidence about the technical, legal, social and economic feasibility of large scale Water2REturn solution for nutrients recovery and recycling in agriculture.

  • Fostering of synergies between the food and sustainable agriculture industries and create new business opportunities and green jobs around nutrient recovery and recycling technologies, especially for SMEs in EU.

  • Promotion of a wide and fast market uptake of Water2REturn processes and products by implementing targeted business plans.

  • Provision of evidence and Policy Recommendations to facilitate market uptake and contribute to the implementation of the EU Action Plan for the Circular Economy.

  • Improvement of the acceptance from final users (meat industry and farmers) and agriculture consumers of Water2REturn final products through capacity building and raise awareness).


  • Decrease of the dependency on primary nutrient resources and increasing the supply security at EU level.

  • Reduction of the adverse effects of nutrient emissions on water bodies.

  • Closing of water and nutrients cycles in the whole production and consumption value chain.

  • Improvement of the quality of data on nutrient flows, thus providing important information for investments into the recycling of recovered nutrients.

  • Creation of new green jobs and industries around nutrient recovery and recycling from water, including fertilizers manufacture and exports.

  • Creation of new business opportunities for industry and SMEs in EU and improving the competitiveness of EU enterprises in the global market.

  • Improvement of policy and market conditions in EU and globally for large scale deployment of innovative solutions for the Circular Economy.

  • Providing of evidence-based knowledge on the enabling framework conditions (such as the regulatory or policy framework) that facilitate a broader transition to a Circular Economy in the EU.



2B (IL)


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Website: water2return.eu/es

Status: Active

Financing program: Horizon 2020 Programme

Contract nº: 730398

Duration: July 1, 2017 – December 31, 2020 (42 months)

Budget: 7.129.322,00€ (CE Contribution: 5.871.895,44€)

Persona de contacto: Pilar Zapata (pzapata@bioazul.com)