Table 4. Summary results of the possible phenolic compounds from different olive processing wastewaters as identified by HPLC analysis and their respective concentrations (in mg/L).
| Suspected compound | Olive processing wastewaters samples | ||||
|---|---|---|---|---|---|
| OMW1 | OMW2 | GTOW | PTOW | BTOW | |
| Hydroxytyrosol | 52.8 | 34.32 | 83.6 | 48.6 | 10.9 |
| Tyrosol | 6.88 | 3.48 | 8.7 | 3.24 | 6.46 |
| p-coumaric acid | 0.16 | 2.72 | n.d | 0.32 | 0.24 |
| Ferulic acid derivative | n.d | 5.72 | n.d | n.d | 0.02 |
| Ferulic acid | n.d | 0.48 | n.d | n.d | 0.06 |
| Oleuropein | 31.36 | 7.4 | 0.66 | 48.8 | 10.82 |
n.d: not detected.