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 Natured Based Solution (NBS) for indoor or outdoor modules in multi-level green walls/ green façades with minimum energy cost (green wall: <1.5kWh/m3; green facade: <2.5kWh/m3) and disinfected using commercial O3/UV systems for obtaining the reduction of tap-water use in the buildings; evaporation losses, will lead to microclimate improvement for the cooling of the building and preventing the heat island effect. 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 also be pre-treated with NBS on the façade. Considering losses through evapotranspiration, rainwater reuse of >95% can potentially be obtained. Facing dry climates locations with low rainfall patterns this amount may vary.

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

NBS will be developed by ALCN. Disinfection using O3/UV will be optimised at lab and pilot scale by LEITAT and finally integrated in buildings in collaboration with ALCN.

The service model will consider a leasing contract and a payment fee per m3 water treated and reused.

Efficient treatment and reuse of rainwater and greywater