determined by solving the following constrained optimization problem using the Excel
Solver. The objective function is to minimize the sum of the squares of the errors
between the calculated and measured outflow concentrations for the 16 STAs. C* is
constrained to be >= 0.007 mg/L. Optimized values of two decision variables k and C*
were calculated as 0.127 days-1 and 0.0194 mg/L, respectively for an assumed average
inflow concentration of 0.102 mg/L.
Table 4-14. Characteristics of 16 STAs in Southeast Florida (Data from Walker and
Kadlec 2005a)
Mean Inflow Outflow Percent
STA Depth HRT Conc. Conc. Removal
(ft) (days) (mg/L) (mg/L)
ENRP C1 1.6 17 0.089 0.039 56%
ENRP C2 2.5 14 0.068 0.034 49%
ENRP C3 1.1 13 0.039 0.019 50%
ENRP C4 2.2 5 0.036 0.017 53%
STA1W C1 2.0 13 0.140 0.05 64%
STA1W C2 2.6 11 0.142 0.088 38%
STA1W C3 1.6 7 0.058 0.033 43%
STA1W C4 2.0 7 0.100 0.032 68%
STA1W C5AB 2.2 7 0.153 0.055 64%
STA2 C1 2.1 22 0.100 0.012 88%
STA2 C2 2.2 14 0.110 0.021 81%
STA2 C3 2.9 17 0.128 0.015 89%
STA5 C1AB 1.7 8 0.121 0.071 42%
STA5 C2AB 1.1 9 0.203 0.125 39%
STA6 C3 1.6 7 0.071 0.019 73%
STA6 C5 1.6 15 0.079 0.016 79%
Average 2.0 11 0.104 0.042 60%
Predicted Performance of EAASR Removal of TP
The calculated outflow concentrations from the EAASR for various assumed
values of initial concentration and residence time are shown in Figure 4-20. For a
residence time of 50 days, the effect of the initial concentration at 50 days and the
associated percent removal is shown in Table 4-15. The percent removal varies from a