Combined Greywater Recycling and Rainwater Harvesting

Stormwater Attenuation

Most new developments will have a requirement to install attenuation to reduce the volume of stormwater runoff entering external drains. Most of the time, this attenuation capacity is designed to be empty and be ready to accept an incoming storm.

 Combined water reuse systems are integrated within into the on-site attenuation system. In urban areas, attenuation capacity usually consists of a blue roof system where stormwater is attenuated on the roof roof as opposed to a more traditional underground storage crate. A blue roof system will hold stormwater on the roof area and slowly release it into the external storm drains.

Via Active Attenuation, Stormsaver can collect and reuse the stormwater within the blue roof system. Active Attenuation is continuously measuring incoming weather patterns 72 hours ahead using Met Office Data.

Active Attenuation can determine the safe level of stormwater in the blue roof to ensure there is enough on-site attenuation capacity for the incoming storm. This allows the stormwater within the attenuation capacity to be reused as a sustainable water supply.

Rainwater Harvesting

The blue roof system is connected to a rainwater harvesting storage tank so that the rainwater can be reused within the building for non-potable use. When the rainwater harvesting tank becomes full to capacity, a valve opens to ensure any excess capacity is released into the external storm drain. The rainwater harvesting storage capacity will be sized in accordance with the collection potential and the total demand meaning the likelihood of the valve releasing excess stormwater into the external drain is lowered.

Greywater Recycling

A greywater recycling system can also be used to top up the rainwater harvesting storage tank or another break tank within the building. The arrangement of combined systems varies depending on the building specification.

Greywater recycling and rainwater harvesting technologies are complementary as when there is a drought period, a supply of reused greywater is still available for the sustainable water supply. Greywater recycling captures lightly used water from showers, hand-wash basins, and bathtubs.

There will also be an automatic mains water top up within the combined water reuse system to ensure a continuous water supply is always available when there is a drought or low greywater supply.