How Do Pressure Filters Work?

Pressure filters are primarily used in the aquaculture industry but are also installed in large residential fish ponds. Pressure filters operate via a pump system and consist of a sealed plastic tank with a filter media that enables mechanical filtration and also provides support to bacterial colonies for biological filtration.

  1. Setup

    • Since pressure filters are not reliant on gravity flow, they are set up in a variety of ways. For example, they can be installed below the water surface level with a submersible pump that moves water into the filter from either the side or over the edge of the pond. For heavy, solid loads, external pumps are used, which draw pre-filtered water from the bottom of the pond.

    Operation

    • Water flows into slots that are equipped with a control valve located at the bottom of the sealed tank. Mechanical and biological filtration occurs at the filter media, which is made up of small ribbed plastic tubes that float in the upper half of the tank. Filtered water flows out of slots at the top of the tank. In the event of backwash, an internal jet separates and removes waste via cyclonic action.

    Filtration

    • Pressure filters are equipped to remove a range of materials, such as dirt, algae, microorganisms, asbestos and metal precipitates. Impurities in the water are distributed over the filtration area of the pressure filter, known as the flow distribution system. The water is then filtered through several layers of the filter bed, and contaminants are strained via the filter media.

    Maintenance

    • During maintenance, the control valves are turned to the backwash position; then the pump runs for approximately 60 seconds. This transfers any accumulated waste to the disposal outlet. The valve is then turned to the rinse position, and the pump runs again to achieve the same effect. It is recommended that this process be repeated at least three times on a weekly basis to ensure optimum operation.