Request a callback

Thank you for choosing to request a callback.

Please fill in the short form below and we will get back to you shortly

We would like to keep you informed by email. Are you happy to receive information from us?


Filter Sand Washing

Watch Video

Filter sand washing systems ensure that the sand used in slow sand filtration remains effective.

Filter sand washing combines physical and biological processes. Fine sand is used to filter sediment in the water passing through. As well as this physical process, the biofilm layer (also known as the Schmutzdecke), biological removes bacteria. 

The Schmutzdecke consists of bacteria, single and multiple cell organisms and algae which effectively filter the water passing through.  The microorganisms in the water are adsorbed by the previously deposited bacteria, allowing pathogen-free water to pass through. 

There are many benefits to the filter sand washing process including its effective removal of bacteria and heavy metals.

The filtration process is highly reliable, and its simplicity is a major selling point. Very little equipment is required and often all that is needed is a housing/reservoir, an under drain system and the filter media.  Slow sand filters usually have a long life-span, and because the process is almost entirely natural and requires no electricity, there is little likelihood of complete breakdowns.

However, put simply, if the sand collects the dirt and other contamination, it eventually becomes less effective. 

Our Solution

An important part of the slow sand filter purification process is maintaining the cleanliness of the sand to ensure clean water and an optimum rate of flow through the filter. The filter is drained and the sand is skimmed off and washed before being laid back down again allowing a new biofilm to develop. 

CDEnviro filter sand washing systems treat the sand to remove contamination, dirt and heavy metals.  This provides our customers with a consistent supply of clean, dry filter sand which is uniform in size and meets all the requirements for slow sand filtration media.  It also provides a reliable and sufficient supply of water. 


Before and After Images

Interested in finding out more?

Get In Touch




View Product