ClearSand intercepts suspended pollutants in wastewater by a deep sand filter bed. The filter bed itself needs to be purified after absorbing pollutants. With the traditional equipment, the processes of filtration and back-washing are divided by time whereas ClearSand, with its centre sand lift column and sand-washer, divides the processes by space and therefore achieves a continuous process of water inlet, filtration, washing and regeneration.
Water flow track: Water in need of treatment enters the sand filtration system and will then be evenly distributed throughout the cross-section of the sand filter bed by water distributor. After that, water flows up and the sand blanket intercepts the pollutants. Then, the filtrate flows out through the outlet on the top of the equipment.
Sand track: Sand, the filtration material, keeps flowing downward under gravity while water flows upward. The sand, together with the attached suspended matters, passes through centre sand lift column at the bottom of the equipment and is raised by air lifting to the sand-washer on the top. In centre sand lift column, the disturbance of gas and water will detach pollutants from sand. Sand returns back to the filter through the maze in sand-washer, where small amounts of countercurrent wash the sand again. Finally, clean sand returns to the top of the sand blanket and starts the next process cycle. At the same time, filtrate containing large amount of suspended matters is discharged from the outlet.
Air track：The circulation of sand is realized by air lifting that compresses the air and the air is discharged from the top of the column. The speed of sand circulation and the intensity of washing can be changed by adjusting the supply of compressed air.