Similarly, a Blue PRO reactive filtration system uses sand coated with ferric oxide (HFO), which attracts and reacts with phosphorus and metals. In the Centra-flo system, sand moves downward by gravity to an airlift device. The filtered water exits near the top of the filter, while the airlift transports phosphorus-laden media up into the washbox where the HFO coating and adsorbed contaminates are separated from the media. Water velocity is designed to carry away contaminates, while also allowing media to fall to the filter bed. The freshly scrubbed media is then recoated with HFO as its cycle begins again. Thanks to its continually-regenerative process, Blue PRO media is not consumable, as the process imparts a temporary chemical coating to the media that is then stripped and recoated cyclically inside the filter.
The Blue PRO process consistently meets ultra-low effluent phosphorus levels, even with permits prescribing less than 0.02 mg/L. For this military base, the system maintains 0.3 mg/L TP or lower, with minimal chemical dosing or waste thanks to our proprietary reactive filtration. Many older sand filter designs were prone to media loss. However, washbox design, unique controls and monitoring systems, mitigates this concern. Both the Blue Nite and Blue PRO systems will waste almost no media in their lifetime, making top ups unlikely, and media should never need to be replaced.