Minimum daily flow. The minimum flowrate that occurs over a 24 hour period based on annual operating data. Minimum flowrates are important in the sizing of conduits where solids deposition might occur at low flowrates.
Minimum hourly flow. The minimum sustained hourly flowrate occurring over a 24 hour period based on annul operating data . Data on the minimum hourly flowrate are needed to determine possible process effects and for sizing of wastewater flowmeters, particularly those that pace chemical-feed systems. At some treatment facilities , such as those using trickling filters. Recirculation of effluent is required to sustain the process during low-flow periods.
For wastewater pumping , minimum flowrate are important to ensure that the pumping systems have adequate turndown to match the low flowrates.