Primary Rainwater Filtration
Primary rainwater filtration is critical to keeping a rainwater tank clean and maintaining a good quality of water inside the tank. A good primary rainwater filter must be able to screen out organic material at high volume flows, separate it from the fresh rainwater and direct it away from the rainwater tank while diverting the clean water to the tank. The bigger the surface area of rainwater recovery the bigger the volume flow of water and the more difficult the filtration becomes. Ideally the filter must require little maintenance be able to integrate into the deign of the structure.
Many people believe rainwater harvesting is simply o pocess of taking a pipe straight from the gutter or recovery surface into a tank. Initially it will work, but very soon as a result of the high organic load water quality will start deteriorating. First the colour of the water starts changing, and after long period of no rain the water will develop a funny smell. The sediment build-up inside the tank starts blocking the pump filters and strainers. If the water tank is drained you will find a thick black layer of de-composing organic material at the bottom of the tank. Cleaning the tank is a dirty job and requires somebody to enter the tank and physically remove all the organic material.
Primary rainwater filters come in many shapes and sizes and need to be selected for every specific application.
In our designs and component spesifications we ensure that the rainwater tank remains clean by installing a very fine primary rainwater filter – like complex Vortex inline filters. These filters strain out any items bigger that 0.28mm to .44mm and they are guaranteed to keep your tanks clean and free of large debris. Minimizing organic material in the tank ensures that the water is not deprived of oxygen which keeps the water fresh for longer.
Vortex filters have the added benefit that they act as a type of first flush system. For these filters to start working effectively they require the surface of the fine filter to become wet. This only happens after about 50-100 liters have passed through them - effectively flushing the first amount of dirty rain water off the recovery surface to the storm-water drain. Thus these filters do not require any first flush systems.
By using a well designed filter the water in the tanks are always clear, taste fresh with no funny smells.
If you just want a relative simple unit you can purchase a inline leaf filter. Depending on the volume flow of the water through the system the units become bigger and can handle a large volume of water. The units are generally sized according to the roof surface that it can capture and filter water from.
See operation of a unit in the video below.
WISY WFF300 filter for rainwater harvesting in industrial applications
The vortex fine filter 300 is installed below ground or indoors in the horizontal rainwater pipe. It filters the rainwater that flows in at the side of the filter unit and releases the filtered rainwater to the storage tank. The filter insert is made of a fine stainless-steel mesh with a mesh size of only 0.38 mm. Leaves, moss and other debris entrained in the rainwater are reliably filtered out and flushed away to the soak-away or drain.
See a link to a video on the operation of the filter
Read more: WISY WFF300 filter for rainwater harvesting in industrial applications
WISY horizontal rainwater filter
WISY our global partner recently launched the WISY Linear Filter K100 horizontal rainwater filter. The filter has been designed on the WISY rainwater filtration principles and was extensively tested in various application before launch.
The space-saving rainwater filter has been designed to specifically filter rainwater in a minimum height difference application, for example within a rainwater tank. It requires minimal differential height. There are just five centimeters height difference between the rainwater inlet and the dirty water outlet. Thanks to this minimal height difference, the linear K100 rainwater filter is extremely easy to integrate into existing pipework. It can even be placed directly inside a rainwater storage tank without changing the gradient of existing piping.
WISY inline rainwater leaf filter
Wisy have introduced a new rainwater leaf filter that can be installed in a gutter downpipe. It acts as a leaf catcher, first flush and overflow protector all in one. It is aimed at the price conscious rain harvesting consumer.
The filter is manufactured from UV resistant polypropylene plastic for the body and stainless steel for the filter element. The filter comes with a 10 year guarantee.
The filter is self cleaning and is virtually maintenance free. It exploits water's tendency to adhere to surfaces to drive the water through the filters vertical filter mesh. This operation is so effective that over 90% of the water flowing through the gutter downpipe is captured. The remaining water is used to flush away the debris that collects on the household's roof. The filter can be used to filter rainwater from a surface as large as 200m2. The filter screen filters all particulates larger than 0.28mm from the rainwater, resulting in clear, odourless water.
