ASAt = P + Q, + GW, -ET-Q,,, -GWo (4-2)
The volume balance components provide the inputs to calculate the hydraulic
residence time (HRT), which represents the water quantity of the system. The HRT is a
function of volume and flow (HRT = V/Q). For a given reservoir volume, V, HRT can be
increased by reducing the inflow rate, Q,,. The other performance measure for the
reactor is the mean operating depth, H. The above information is obtained from the
output file for the SFWMM by aggregating the cell by cell data.
Water Quality Characterization
Water quality characterization of the system is based on the inflow concentration,
Cin, the rate parameter, and the minimum concentrations. As storage and water quality
changes are inseparable, the characterization of the water quantity affects the
characterization of the water quality.
Inflow concentration
The inflow concentration, Cin, is a function of the source and quantity of inflows.
The water quantity of the system uses an aggregate inflow, Qin. Therefore, a single
representative concentration is assigned to the aggregate inflow. If more than one inflow
source exists, a flow weighted concentration is calculated from Equation 4-3 where Qi is
the flow, Ci is the concentration, and "i" designates the source.
ZQ'c,
Cn n= (4-3)
ZQ,
1=1
Removal rate
The KC* removal rate equation is used to represent pollutant concentration
profiles with time in a variety of reactor systems including wetlands (Kadlec and Knight