Horizontal Flow

Horizontal-flow clarifiers might be rectangular, square or circular in shape. The flow in rectangular basins is rectilinear and parallel to the long axis of the basin, whereas in centre-feed circular basins, water flows radially from the middle towards the outer edges. Both kinds of basins are designed to keep the velocity and flow distributions as uniform as possible in order to avoid currents and eddies from forming, and thus keep the suspended material from settling. Basins are commonly made of steel or reinforced concrete. The bottom surface slopes slightly to facilitate sludge removal. Inside rectangular tanks, the slope is towards the inlet end, although in circular and square tanks; the bottom is conical and slopes towards the middle of the basin.