Time shift control of wastewater pumping system

Abstract

Reservoir flow or surge control systems frequently have large installed lifting or pumping capacity to deal with variations in either inflow or outflow, or both, and may form a part of a larger system of many such reservoirs. Taken together these reservoirs may have significant storage capacity. In operation such systems are large consumers of electricity. Electricity is often priced differently at different times of day. This invention employs this storage capacity to permit energy consumption to be shifted, at least in part, from periods of high electricity prices to periods of low electricity prices. This is done by permitting a greater amount of material to collect during periods of expensive electricity, and then removing the material to a lower level during periods of less expensive electricity, or the reverse, depending on the nature of the system and the material in question. Either an `On-Off` or flow rate control method of pump control may be used. The invention is illustrated by application to a wastewater pumping system. In this case a control unit works in conjunction with a pulse-echo acoustic level sensor to control the operation of a battery of wastewater pumps at wastewater pumping stations in an urban sewage system.