Existing systems
Most commercially available first flush diverters consist of a wastewater tank containing a floating
ball. This floating ball is designed to
block the inlet to the wastewater tank as
it fills with the first flush. This then forms
a barrier between the first flush that
could contain contaminants and the
clean rainwater that is to be used for
drinking water. This system has been
adapted by rainwater harvesting pty ltd
located in Brisbane.
Figure 1 rainharvesting.com.au
Another method adapted by superwall has replaced this floating
ball with a one-way funnel. This funnel contains small holes to
prevent airpockets. This design catches floating debris behind
the funnel and requires an additional brush to filter out the
smaller particles.
Figure 2 Superwall.com.au
Saferain sells a product that does not store the water from the first flush. The diverted water drains
straight from the system and can divert anywhere from 0 to 2000 litres of water. Rather than a
slowly draining setup as is used in other systems, this product fully resets after 24 hours.
Figure 3 www.saferain.com.au
Rutland gutter supplies sells downspout diverters made from copper and aluminium. These
downspouts need to be adjusted manually to change the destination of the water. These systems
are designed with a close eye on architectural features.
Figure 4 www.rutlandgattersupply.com
Another design uses a baffle that spreads the flow. This reduces the flow of contaminated water in
the wastewater tank and eliminates the need for separation of contaminated water from the cleaner
drinking water.
Figure 5 Australian patent number 2007100365
The raindog first flush system uses a valve that closes as a result of a buoyant force. This valve then
remains closed as a result of the weight of the water on top of the valve. This allows the wastewater
to drain from the system during the rainfall while continuously diverting the water to the drinking
tank.
Figure 6 Raindog.com.au
http://www.raindog.com.au/web_images/for-underground-tanks-4.jpg
References:
rainharvesting.com.au
Superwall.com.au
www.saferain.com.au
www.rutlandgattersupply.com