100%
 90%
 80%
 70%
S60%
 50%
S40%
v 30%
 20%
 10%
 0%


-- EAASR Cin
- EAASR Cout
- STA 3/4 Cout


 0.0 50.0 100.0 150.0
 TP concentration, ppb

Figure 5-4. Mean Annual Inflow and Outflow Concentrations from SC STA Scenario

 Summary and Conclusions

 The overall results for the three configurations are shown in Table 5-15. The

input TP concentrations vary from 0.067 to 0.133 mg/L depending on the number of

compartments. Similarly, the output concentrations from the EAASR indicate a

significant treatment effect with the concentrations reduced to 0.028 to 0.063 mg/L

depending on the configuration. However, the variability in performance is greatly

dampened in the STA 3/4 outflow with the outflow concentrations all very similar in the

0.020-0.021 mg/L range. The EAASR has a significant water quality impact because its

hydraulic residence times exceed two months. The residence times in STA 3/4 are also

high for an STA with a calculated mean of about 29 days. Thus, the combined system

has ample time to store and treat the water. The EAASR can also provide a significant

ability to manage the inflows to STA 3/4 in order to optimize its performance. From an

operational point of view, it is desirable to maximize the amount of inflow that can be

passed through the EAASR before entering STA 3/4.