Table 2 The maximum allowable limits according to the Jordanian standards compared to this research and the mean values of the characteristics of OMW for the pretreatment step and VFCWs step (SD = 0.05 – 0.83)
From: Olive mill wastewater treatment using vertical flow constructed wetlands (VFCWs)
| Â | Pretreatment | VFCWs | Â | Â | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Characteristics | OMW inlet | OMW outlet | % | Un-planted outlet | % | Overall % removal | planted outlet | % | Overall % removal | Max. allowable conc. for sewage-discharged wastewater | Max. allowable conc. of reclaimed water for Wadi discharge | |
pH | 4.83 | 6.81 | – | 7.08 | – | – | 6.99 | – | – | 5.5–9.5 | 6–9 | |
CODT (g/L) | 37.61 | 10.82 | 71.32 | 3.20 | 70.41 | 91.51 | 0.81 | 92.50 | 97.80 | 1500 | 150 | |
CODd (g/L) | 10.82 | 7.40 | 31.50 | 2.44 | 67.61 | 77.83 | 0.78 | 89.51 | 92.82 | – | – | |
TPC (ppm) | 182.58 | 8.51 | 95.31 | 2.73 | 68.22 | 98.69 | 0.74 | 91.33 | 99.61 | 5 |  < 0.002 | |
TN (ppm) | 610.60 | 46.78 | 92.36 | 15.10 | 67.70 | 97.54 | 6.70 | 85.74 | 98.92 | 100 | 70 | |
Ammonium (ppm) | 2.86 | 0.63 | 78.04 | 0.23 | 63.52 | 92.34 | 0.09 | 85.72 | 96.91 | 120 | 5 | |
Nitrate (ppm) | 102.52 | 24.32 | 76.33 | 9.45 | 61.10 | 90.81 | 4.31 | 82.30 | 95.78 | – | 80 | |