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What is First-Flush Technology?

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Along with cleaning your tank regularly and checking for dirt, growths and leaks, the fellas at Greenrock also suggest first-flush technology as being mandatory for each household “as a matter of public health”. In recent studies, findings are telling that as roofs are exposed to bird droppings, dust, leaves of trees deposited on the roof, it is of utmost importance to flush the harmful matter from the roof before it falls into the tank.

Since the settlers came to Bermuda, the rainwater catchment system has been in place. First-flush diverter devices (that remove the unwanted matter getting into the tank) can be seen since Ancient times around the world. Rainwater collected while using a first-flush system enhances the quality of drinking water and considerably reduces water borne diseases.

A first-flush diverter is a simple contraption that diverts the first flow of water away from a rainwater catchment system. The first pass of water in any storm essentially washes your roof of all the sediments that have collected since the last rain. The idea is that diverting the first flush can help ensure cleaner water in the tank. Water diverters improve water quality, reduce tank maintenance and protect pumps by preventing the first flush of water, which may contain contaminants from the roof, from entering the tank.

These systems also protect rainwater pumps and internal household appliances such as clothes washing machines, toilets and hot water systems.

Many experts criticize the extra attention that it takes for these systems to run smoothly, but some devices use a dependable ball and seat system – a simple automatic system that does not rely on mechanical parts or manual intervention. As the water level rises in the diverter chamber, the ball floats, and once the chamber is full, the ball rests on a seat inside the diverter chamber preventing any further water entering the diverter. The subsequent flow of water is then automatically directed along the pipe system to the tank.

Features and Benefits

  •  Prevents sediment, bird droppings, spiders, insects, mosquito eggs and debris from entering the tank.
  • Improves water quality, protects pumps and internal appliances.
  • Ideal to use in conjunction with a rain head.
  • Easy installation.
  • No mechanical parts.
  • Low maintenance requirements.
  • Cost-effective.

How do they work?

When it rains, water slowly builds up in the roof guttering system before it exits through the downpipe. The first flush of water from the roof can contain amounts of bacteria from decomposed insects, bird and animal droppings. It may also contain sediments, water borne heavy metals and chemical residues, all of which are undesirable elements to have in a water storage system.

Instead of flowing to the water tank, these pollutants are diverted with the initial flow of water into the chamber of the water diverter.

For a water diverter to work effectively, the contaminated water in the chamber must be sealed off. This prevents the water passing to the storage tank and ensure the water does not carry off the contaminated water in the chamber. The simplest and surest way to do this is with a floating ball and seat. A slow release valve ensures the chamber empties itself after rain and resets automatically.

For those in Bermuda that use the rain catchment system (and that’s just about everybody) these are the types of ideas that we should continue to keep in the conversation of sustainability and general public health. To chat with Greenrock about other good ideas or learn more about the issues that are affecting our island environmentally, contact them at [email protected]

This article was originally published in the June Edition of the RG Green Pages supplement.

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