|
|
Table 2. The independent variables and their levels for the experimental design with central point. |
|
Variables |
Levels |
||
|
+1 |
0 |
-1 |
|
|
X1– Calcium Carbonate Concentration (g/L) |
1.0 |
0.8 |
0.5 |
|
X2 – Aeration (vvm) |
1.3 |
0.8 |
0.2 |
|
X3 – Agitation (rpm) |
800 |
500 |
200 |
|
|