Regulating water circulation from sedimentation basin to overflow tank

摘要

A water recycling plant has a sedimentation basin (1) connected via water outlet holes (4) to an adjacent overflow tank (6). Water for use in a process plant (11) is drawn from the overflow tank and circulated back to the basin (1). The rim of the basin (1) and the rim of the overflow tank (6) are arranged at substantially the same level which is sufficiently far above the outlet holes (4) to provide a head of water at which the overflow water from the basin to the overflow tank corresponds to the maximum water consumption of the process plant (11). The water levels in the basin (1) and overflow tank (6) are regulated to be above the outlet holes (9). The launder (5) may act as the overflow tank. Slurry removal from the bottom of the sedimentation basin (1) is controlled at (9) by the water level in the basin actuating a maximum/minimum alarm. The arrangement ensures that an adequate flow of overflow water is available at all times to meet the demands of the process plant (11) fed from the overflow tank (6) and the addition of fresh water or disposal of excess process water is minimised.