S5

Efficient treatment and reuse of rainwater and greywater

Greywater and blackwater can be separated with retrofitting measures in existing buildings. Greywater can be treated using innovative nature based solutions for indoor application in multi-level green walls with minimum energy cost (<1.5kWh/m3) and disinfected using commercial O3/UV systems for >90% water reuse.

Water meters at household and building level can show the amount of water reuse for toilets recharge or irrigation. On the other hand, rainwater can be also pre-treated with nature based solutions on the façade or roof area. Here, we will have also a loss through evapo-transpiration, potentially obtaining >95% rainwater reuse or minor in dry climates locations with low rainfall patterns.

The service model will consider a payment fee per m3 water treated and reused. This solution will be developed and demonstrated at laboratory and semi-pilot scale prior to implementation at large scale (Demo buildings). Operating parameters obtained in lab scale tests with nature based solutions will allow the optimisation of O3/UV technologies as well as the proper dimensioning of nature based solutions for final integration.

Efficient treatment and reuse of rainwater and greywater