Stormwater is a poorer quality water source compared to roofwater and environmental approval may be required to divert stormwater. A stormwater harvesting system can deliver significantly greater water savings than a roofwater harvesting system as runoff is diverted from both roof and non-roof catchment areas.
A sites topography and drainage network dictate how stormwater can be diverted into a harvesting system and the diversion system can be a significant cost component. Storage is also a major cost component and optimising capacity is a focus of design.
The stormwater treatment process varies depending on raw water quality and end use requirements, however it typically involves media filtration and disinfection. A centralised control system with a network of wireless sensors allows harvesting systems to be fully automated with quick detection of performance issues and easy tracking of water savings.
Key engineering considerations for stormwater harvesting systems are summarised further below and in the attached brochure.
Key considerations:Diversion point and catchment area Diversion capacity System needed to divert stormwater without increasing flooding risks
The treatment process varies depending on the raw water quality and the end use, however it typically involves media filtration to reduce cloudiness and UV or chlorination disinfection.
Key considerations:Need for raw and treated water storage Storage and treatment facility location and capacity Pre-screening mechanism and aperture Level of filtration, disinfection and chemical adjustment needed to meet end use requirements
Key considerations:Delivery pump type and activation mechanism Need for and location of potable back-up