Table 1.
Characteristics of raw wastewater and activated sludge (No. of samples = 7).
| Parameter | Min | Max | Average | Std. Dev. |
|---|---|---|---|---|
| Raw wastewater | ||||
| BOD (mg/L) | 573 | 1177 | 875 | 427.09 |
| COD (mg/L) | 777 | 1825 | 1301 | 741.04 |
| NH3-N (mg/L) | 56.7 | 104 | 80.35 | 33.44 |
| Nitrite (mg/L) | 45.3 | 80 | 62.65 | 24.53 |
| Nitrate(mg/L) | 52.6 | 178.4 | 115.5 | 88.95 |
| Oil-grease (mg/L) | 2361.5 | 3616 | 2988.75 | 887.06 |
| TSS (mg/L) | 395 | 783 | 589 | 274.35 |
| pH | 6.3 | 6.9 | 6.6 | 0.4242 |
| Activated sludge | ||||
| BOD (mg/L) | 1246 | 1548 | 1397 | 213.54 |
| COD (mg/L) | 51,248 | 59,345 | 55,296.5 | 5725.44 |
| DO (mg/L) | 0.65 | 0.68 | 0.665 | 0.0212 |
| MLSS (mg/L) | 47,000 | 59,000 | 53,000 | 8485.28 |
| pH | 6.75 | 6.85 | 6.8 | 0.0707 |
BOD: biochemical oxygen demand; COD: chemical oxygen demand; TSS: total suspended solids; DO: Dissolved oxygen; MLSS: Mixed liquor suspended solids.