Constructed wetlands (CWs) are considered inexpensive and commonly used technology for treatment of wastewater worldwide. This research focused on evaluating the performance efficiency of four selected constructed wetlands located in Sarra, Hajjah, Misillya, and Biet Hasan villages, all in the north of West Bank. Wastewater samples were collected from the studied plants between 10 am and 13:00 pm overtime (October, 2018 to February, 2019. The samples were collected three times over the period. The collected samples were analyzed for EC, pH, BOD5, COD, T. Phosphorus, T. Nitrogen, TDS, TSS. Dissolved Oxygen and temperature of wastewater were recorded onsite at the same time of the sampling.
The overall removal efficiency in terms of removal organic pollutants (BOD5, COD, TSS) was the highest in Sarra then Misillya and Hajjah treatment plants, while Beit Hasan plant had the lowest performance. Although Sarra and Hajjah plants in terms of removing organic pollutants (BOD5, COD, TSS) were achieved overall good performance and above 90%; the effluent characteristics (BOD5, COD, TSS) from both of them failed to meet good quality grade according to the Palestinian obligatory technical specifications (PSI 34-2012). Reduction of organic pollutants (BOD5, COD, TSS) from effluent of Biet Hassan failed to meet with (PSI 34-2012). Furthermore, effluent characteristics of Misillya treatment plant failed to meet the Palestinian obligatory technical specifications (PSI 34-2012) in terms of BOD5, but COD, and TSS met with Grade D (low quality) of (PSI 34-2012). In terms of treatment stages for Sarra and Hajjah plants VF beds achieved higher performance compared to the other treatment stages, while in Misillya plant recirculation stage achieved higher performance. The poor performance efficiency of beds of Misillya WWTP probably due to uncompleted maturity of bed that meaning it was still not reached steady-state.
Analysis of data showed promotion of performance efficiency for Sarra, Hajjah, Biet Hasan wetland plants is necessary that could be achieved by maintenance of reed beds to avoided clogging and management of dominant plant (reed common) by harvesting and replanting of plants, as well as removal of undesirable vegetation.
Keywords: Constructed wetlands; Wastewater; Treatment efficiency.