Humes Water Solutions – Downpipe Filtration for Rainwater Harvesting Systems
Humes Water Solutions provides a range of high quality European filtration devices as a component of the award winning RainVaultTM and RainBarelTM rainwater and stormwater harvesting systems. These devices effectively separate leaf litter, organic material and solids from rainwater to ensure trouble free operation of the harvesting system for the long term with very little maintenance being required from the property owner. These same filtration devices are now also available from Humes Water Solutions as separate items for use on any above or below ground harvesting solution being proposed.
The range of filters available from Humes Water Solutions includes two downpipe filters for continuous and direct separation of solids material prior to flow being directed to the rainwater tank or water harvesting system. This includes the Collector Downpipe Filter and the Rainus Downpipe Filter. For below ground filtration options, please refer to Filtration under the Below Ground Water Harvesting tab.
Both filters have been developed by a leading European company who have over two decades of experience in the provision of rainwater harvesting solutions. Some 80,000 harvesting systems are installed across Germany every year and 80% of those systems rely on the same filtration technologies now available across Australia through Humes Water Solutions.
Collector Downpipe Filter
The collector downpipe filter is a simple single stage screening device which provides effective continuous separation of coarse solids material, prior to flow entering an above ground rainwater tank or below ground water harvesting system.
Each filter is suitable for roof areas up to about 70 m2 and readily accepts downpipes up to 100 mm in diameter. An adaptor is available to suit 100 x 50 mm rectangular downpipes. The operation of the Collector Downpipe Filter is as follows:
1. Rainwater is channelled from the filter entrance to the sieve cartridge which incorporates a 0.87 mm stainless steel screen
2. Solids are rinsed to the sides of the screen and continue past the screen along the down pipe to the stormwater outlet
3. Clean filtered water passes through the screen and is channelled through the cartridge outlet to the storage tank
Rainus Downpipe Filter
The Rainus Downpipe Filter operates on the same dual cascading inclined screens as the larger below ground filter options (refer Filtration). Each filter is suitable for roof areas up to about 70 m2 and readily accepts downpipes up to 100 mm in diameter. An adaptor is available to suit 100 x 50 mm rectangular downpipes. The operation of the Rainus Downpipe Filter is as follows:
1. Baffles within the upper filter housing dissipate some of the energy of the falling water within the downpipe
2. Rainwater enters the filter and further energy is dissipated in a small basin behind the filter screens
3. Rainwater overtops a small sharp crested weir ensuring even flow distribution across the whole width of the primary cascade
4. The primary cascade separates out larger leaf litter items and solids, which are flushed across the cascades to the front opening. Water and smaller solids pass through the cascade openings and onto the finer secondary filter
5. The finer secondary filter is located behind and below the primary cascades, where pre-filtered water flows over the inclined stainless steel screen. This screen separates out solids material down to about 0.5 mm in size. The special aperture of the mesh allows separated solids to be flushed off the end of the screen to the waste opening at the front of the filter providing a self cleaning maintenance free operation
6. Leaf litter, separated solids and organic material are ejected from the front of the filter
7. Filtered clean water exits the bottom of the filter to the rainwater tank, the storage component of a RainVaultTM water harvesting systems, other storage vessel or infiltration system.
Why Use Filtration in Rainwater Harvesting Systems
Rainwater contains a range of contaminants from leaf litter, twigs and organic material to solids and dirt deposited across the roof. These solids in turn carry with them a range of other contaminants (including bacteria) which ideally should be removed prior to the storage of water within a harvesting system. Allowing such material to build up within the storage system may inevitably lead to the following poor outcomes:
- Odours as organic material decomposes, with potential harmful by-products
- Generally poor quality water
- Clogging of downstream irrigation nozzles
- Damage to pump impellers, burn out of motors and generally lower pump life
- Expensive maintenance of the storage system to remove accumulated solids, which may be required annually without effective filters
Simple first flush diverters may assist in separating some of these solids, however, recent research has suggested that the benefits of first flush devices are limited in the long term since their effective operation rely heavily on routine monthly inspection and maintenance by property owners. Once engaged, first flush devices provide next to no continuous treatment of rainwater flowing from a roof area.
The filtration devices provided by Humes Water Solutions are advanced systems and have been developed to provide effective operation over the long term without relying on routine maintenance by property owners. All filters provide inclined self cleaning screens which provide a very low maintenance operating regime and continue to provide complete treatment and separation of all solids material for 100% of the flow that ends up being stored within the storage system.
Please call your local Humes Water Solutions representative (in South Australia on 8168 4501) or the toll free number 1300 361 601 for further information, technical support and pricing.
