Table 3.
Physicochemical characteristics of the used process watersa
| Parameter | Mean value ± SD |
||||
|---|---|---|---|---|---|
| SPW COD 500 mg O2/liter | SPW COD 800 mg O2/liter | SPW COD 1,500 mg O2/liter | Company 1 | Company 2 | |
| pH | 7.6 ± 0.1 | 7.5 ± 0.1 | 7.6 ± 0.02 | 7.34 ± 0.01 | 7.2 ± 0.1 |
| Turbidity (NTU) | 66.4 ± 5.4 | 118.4 ± 20.7 | 228.0 ± 50.5 | 13.8 ± 0.9 | 72.6 ± 6.6 |
| COD (mg O2/liter) | 510 ± 20 | 772 ± 20 | 1,430 ± 58 | 465 ± 2 | 1,405 ± 57 |
| UV254 | 1.58 ± 0.05 | 2.40 ± 0.06 | 3.74 ± 0.39 | 0.36 ± 0.03 | 1.08 ± 0.05 |
| UV254(F) | 0.82 ± 0.05 | 1.40 ± 0.11 | 2.12 ± 0.21 | 0.22 ± 0.02 | 0.70 ± 0.02 |
| Fe (mg/liter) | ND | 0.72 ± 0.07 | ND | 0.19 ± 0.005 | 0.22 ± 0.01 |
| Mn (mg/liter) | ND | 0.070 ± 0.0002 | ND | 0.013 ± 0.002 | 0.024 ± 0.003 |
| NH4-N (mg/liter) | ND | 0.45 ± 0.03 | ND | 1.13 ± 0.03 | 0.89 ± 0.05 |
a
ND, not determined; NTU, nephelometric turbidity units.