The HUBER Sandfilter CONTIFLOW® is a deep-bed type upflow filter with continuous filtration and discontinuous filter bed cleaning (1.0 – 2.0 mm sand grain size) that meets even the highest effluent quality requirements. The filter is highly efficient as no shutdowns are necessary for the sand washing process.
Depending on the specific local conditions on site, the system is installed in a stainless steel tank or in a concrete tank. Its modular design ensures the optimal treatment of any throughput. Depending on the required effluent quality or inlet concentration, the system uses filtration velocities of up to 14.0 m/h.
The feed is introduced into the HUBER Sandfilter CONTIFLOW® through a feed line which leads to a series of feed radials at the bottom of the filter. As the influent flows from the bottom upward through the sand bed (mostly 2.0 m sand bed height), the solids contained within the influent are retained in the filter sand (solids including particulate phosphorus). The filtrate exits over a weir at the top of the filter.
As the loading of the filter bed with solids increases, the primary pressure required for the flow through the filter rises (Δhmax < 1200 mm). When a defined pressure switch point is reached, the solids (including the particulate phosphorus) are delivered upwards by an airlift into the washer unit. Inside the washer, the solids are separated from the filter sand due to the different settling velocities.
They are washed out along with a small portion of the filtrate flow, the so-called wash water. The clean sand falls down through to the bed, generating an internal sand circulation in the HUBER Sandfilter CONTIFLOW®.