ABSTRACT
Wastewater treatment plants need a flow measurement to determine solids and BOD loading to the plant, and to the receiving stream for NPDES compliance. Knowledge of incoming water quantity is vital to anticipation of plant reaction to industrial input, shock loads, and storm water. The sizing of stormwater retention basins to prevent flooding and backup is based on a flow reading. Venturi meters, like orifice meters, measure flow in closed conduits by recording a pressure differential across a constriction in the pipe. It can be used over a wide range of flows, and has a low permanent head loss because of the smooth configuration. In water filtration facilities which operate constant rate filters, the rate of flow through the filters is regulated by a valve/venturi mechanism, the Flow Rate Controller. To measure flow in sewers, streams, drains - open channels - weirs have become most popular.
