Question

Define the following flow terms, average daily flow, maximum day, peak hour, and minimum day. For each of these flow terms, provide at least two sample applications in the design and operation of wastewater treatment facilities. 6

Answer 1

Average daily flow: the average of the daily volumes to be received for a continuous 12 month period expressed as a volume per unit time.The average daily flowrate is used in evaluating treatment plant capacity and in developing flowrate ratios use d in d i es gn

Maximum day: the largest volume of flow received during a continuous24 hour period expressed as a volume per unit time. The largest volume of flow anticipated to occur during a one-day period, expressed as a daily average. The maximum daily flowrate is important particularly in the design of facilities involving retention time such as e qualization basins.

Peak hour: peak hourly flow is the largest volumeof flow to be received during a one hour periodexpressed as a volume per unit time.Data on peak hourly flows are needed for the design of collection and interceptor sewers, wastewater-pumping stations, wastewate r flow meters, sedimentation tanks and channels in the treatment plant.

Minimum day:  the least volume of flow received during a continuous 24 hour period expressed as a volume per unit time. The smallest volume of flow anticipated to occur during a one-day period, expressed as a daily average. Minimum flow rates are important important in the sizing of the conduits conduits where solids deposition might occur at low flow rates.