Hydrasand - Continuous sand filter

Operating principle

Raw influent is fed into the base of the sand-filled, cone-bottomed filter. The flow then rises through the sand so that clean effluent is discharged over the upper weir. The rising flow of the effluent is distributed evenly over the entire cross-section of the filter by means of a radial grating system.

The contaminated sand falls continuously to the bottom cone outlet, from where it is transferred by an external airlift to the wash chamber at the top of the unit. Final backwashing of the sand is then performed by a counter-current of clean water before the sand returns to the sand bed in the isolation box. The dirty wash water is discharged over the lower weir for disposal.

Benefits

• High filtration efficiency
• External airlift for better accessibility
• No possible contamination of clean water by returning sand
• Efficient final sand rinsing in the isolation box
• Manageable reject stream
• Minimum maintenance cost
• Minimum energy requirements
• No shutdown for backwashing
• No moving parts
• No backwash material required

Features

• Continuous operation and cleaning
• Superior lift and scouring of sand
• Adaptability of sand bed depth
• Flexibility of design
• Stand-alone unit in stainless steel.
• Available in concrete version with stainless steel insert, offered to keep transport costs down or for high flow rates.

Applications

Range

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