Sustainable water treatment in the mobble

Bio-science engineers are part of the Ghent University Solar Decathlon Team

Because closing the cycles is central in the concept of The Mobble, there is a focus on sustainable water management and wastewater treatment with reuse. This is where the team of bio-science engineers comes in: Prof. Bart De Gusseme, Marjolein Vanoppen, Jan Arends and Dries Seuntjes (DuCoop) demonstrate a decentralized water treatment that allows the recovery of resources, energy AND water from domestic wastewater in The Mobble. These resources are becoming scarce and their production has an increasing environmental impact. This concept is already applied in a few pilot projects at neighborhood level, also in Ghent, and is further developed within the Centre for Advances Process Technology for Urban Resource Recovery or CAPTURE, a new research centre focused on closing the cycles for a circular economy.

Sustainable water treatment with reuse

The wastewater from toilet and kitchen are collected separately by a system under vacuum. This organic fraction is converted into biogas by a low oxygen (anaerobic) microbiological process. The biogas can be used for the production of heat and electricity. Fertilizers for plants, such as struvite, can also be recovered. The other wastestream orginates from the bathroom, the washing machine and the dishes. This ‘grey’ water leaves our homes at 30°C, containing residual heat. After biological treatment in a membrane bioreactor, this heat is recovered in a heat exchanger and coupled heat pump.

This circular system for water treatment will be applied this year in “De Nieuwe Dokken’ in Ghent, an ambitious and innovative project by contractor MAES. In this neighborhood, 400 residences will be connected to this water treatment and coupled to a district heating grid, recovering 35% of the heat demand and 1,5 tons of struvite per year. Moreover, 30.000 m³ of wastewater is available annually, which FARYS wants to reuse as process water in industry in the same area. This results in a total reduction of 70% of the CO2-footprint of the district when compared to conventional treatment and heating.

The treated wastewater can also be reused within the homes, together with rainwater. After activated carbon filtration, to remove color and odor, the water is perfectly suited for flushing, cleaning, gardening or washing. Additional disinfection by UV or electrochemistry allows reuse of the recycled water in the bathroom and as drinking water in the kitchen. Together with water-efficient appliances, this results in a household saving up to 48%, providing an answer to climate change and water scarcity that is recently becoming very tangible, even in Flanders. 

In collaboration with MAES (contractor), Roediger (vacuum installation), RENI (advisors rainwater recovery FARYS) and the cooperative DuCoop (www.ducoop.be), with support of the European Interreg-project Nereus (De Nieuwe Dokken).