The city of Ghent, Belgium, is renewing the Northern district. As part of this renewal, the “Oude Dokken” (industrial site) is repurposed as a residential neighbourhood “De Nieuwe Dokken“. This is one of the demonstration sites of Run4Life. It will accommodate an innovative waste and wastewater management system for 430 houses and a variety of other buildings, serving around 1200 person equivalents. Toilet wastewater (black water), organic kitchen waste and other domestic wastewater (grey water) will be collected and treated. The goal is to reuse all the wastewater, by recovering nutrients and energy and reusing the treated wastewater in the neighbouring industry. At full deployment, the Nieuwe Dokken district, will be a prime example of circular economy with synergies between water, nutrients and energy, as well as private households and industries.
Project partner CEIP and DuCoop manage the demo site within Run4Life. The collection and treatment of grey water are activities outside the Run4Life project, see also the website of the Nereus Project. The first buildings have been connected to the vacuum system and as apartments become available the inhabitants will be moving in.
Resource synergy between homes and industry
The resources (energy, water and fertilisers) gained from kitchen waste, black water and grey water produced in households can be reused the city’s energy network, in industry and in agriculture, resulting in a synergy between homes and industry. How does this work?
Black water is collected by vacuum toilets and the kitchen waste is collected by means of shared grinders outside the homes. These waste streams are mixed and then treated by anaerobic digestion in a UASB reactor. During this anaerobic process biogas is produced. Biogas is converted to energy which can be put into the district heating network. From the effluent and sludge output of the anaerobic digestion, three further products are obtained; extra grey water, struvite (a phosphate fertiliser) and phosphoric acid (a phosphate fertiliser, still explored).
Grey water is collected by a gravity sewer and treated in an aerobic membrane bioreactor (aMBR). The produced sludge is sent to the UASB reactor as an additional carbon source for biogas production. The remaining heat present in the treated water is recovered with a heat exchanger and added to the district heating network. Finally, a nearby detergent industry is also integrated in the concept: the treated grey water is polished to meet process water quality for the detergent production.
As many people, companies and organisations are involved in the Run4Life project, it is interesting to see how these groups are connected to one another and how they are involved in the project. This can help with identifying possible new stakeholders and collaborations. For this purpose, stakeholder maps for each demo site were created. The stakeholder map is a tool that shows the connections between stakeholders and can therefore help visualise the social context. The initial mapping of stakeholders and expectations for all demo sites is described in project report Deliverable 6.1 and more information on the social context of Run4Life can also be found here.
Corresponding fact sheets (under development):
- Ghent demo site
- UASB (anaerobic digester)
- Struvite precipitation
- phosphoric acid