Pressurized physical filtration

Filtration is the final step in a standardized treatment system. In certain applications, we use pressurized physical filtration units filled with sand or glass media. The key advantage of these filters is that they can be cleaned and reused through backwashing.

Sand or glass media

Sand filtration is a water treatment method that removes particles and particle‑bound contaminants through a physical barrier. This process helps reduce suspended solids and improve water clarity. The technique is used in both construction and industrial projects, particularly in situations where high treatment standards are required or when it is necessary to protect downstream sorption filter stages from particle loads.

In Swedish Hydro Solutions’ sand filtration systems, either glass or sand media is used, depending on the specific needs of the project. Factors such as particle size, flow rate, and required water quality standards play a decisive role in determining the optimal filter media for the intended system.

Pressurized filters are supplied both as containerized units and as standalone systems, often custom‑designed to meet the client’s specific requirements.

How backwashing works

One advantage of pressurized filters with sand or glass media is that they can be backwashed. During backwashing, water is directed in the opposite direction through the filter to remove the particles and contaminants that have accumulated in the media bed during operation.

Over time, resistance through the filter increases. When the pressure drop becomes too high, the valve settings are adjusted so that water is pumped upward from the bottom. In some cases, air is also introduced to agitate the media and release particles before the backwash begins.

As the water flows upward, the media bed expands, allowing trapped particles to loosen and be carried away with the backwash water. The backwash water can then be discharged to a sedimentation container. Backwashing continues until the water leaving the filter is clear, after which the filter returns to normal operation with a clean and re‑aerated media bed.