The dire situation and various challenges in the current management of industrial wastewater in Palestinian communities are the drivers behind this research study. Rapid urban expansion contributes to increased municipal wastewater generation (MWW) and inadequate wastewater treatment (WWT) which leads to deterioration of the receiving environment, poses health risks and leads to deterioration of sewage infrastructures. This study investigates the effectiveness of a pilot system, installed at Birzeit University campus, which includes UASB system pretreating industrial wastewater mixture from a chicken slaughterhouse and an olive press (Zibar). This system follows a post-treatment in parallel treatment systems; waste stabilization ponds (WSPs) and vertical flow constructed wetlands (VFCWs). The effect of mixing ratios of industrial wastewater on the efficacy of UASB system and the effect of hazardous pollutants (phenol and some elements of heavy metals) on biogas production measured. Laboratory analyzes of physical and chemical parameters performed on the effluent in the UASB system and in the outlet. Two UASB experimental reactors were installed on the campus of Birzeit University to treat mixed industrial wastewater from olive mill water (Zibar) and chicken slaughterhouses. The two reactors were operated in parallel for a period of four months at ambient temperatures ranging between 25-35 ºC. The operation was carried out in two different stages. The first stage works at two different speeds, the feeding rate of the first system (UASB 1) was 166 l/day, the second system (UASB 2) was 230 l/day, and the Zibar ratio was 5%. While in the second phase the pump was installed at a feeding rate of 155 l/day, and the rate of Zibar increased to 10%.

Samples were taken from the two systems inlet and outlet and analyzed inside the university's laboratories. The table below lists the design parameters including the results obtained including the removal efficiency rates for the key parameters during the first and second operational phases.

The wastewater treatment of mixed industrial water was studied using the UASB anaerobic reactor over a period of 4 months. As this system was operated under different operating conditions (different feed flow rates of the two systems, organic loading rate, and different hydraulic retention time), to remove organic matter and solids from mixed industrial wastewater. The organic pollutants were removed in the UASB anaerobic reactor, and the removal efficiency rate of first stage was for the COD, VSS, TSS, TKN, and Total Phenol were 36.1%, 68%, 51%, 16.8%, 100%, respectively, for the UASB 1, 61%, 69%, 74%, 24% and 100% respectively for the UASB 2. As for the heavy elements, the rate of removal efficiency ratio for Zn, Cr, and Cu were 38.8%, 54.8%, and 83.8%, respectively for the UASB 1, and 9.45%, 57%, and 83.8% respectively for the UASB 2, and the components Cd and Pb were not present for both. The removal efficiency rate for the second stage was for the COD, VSS, TSS, TKN, and Total Phenol were 64.6%, 71%, 80%, 39.5%, 100%, respectively for UASB 1, 59.6%, 73%, 77%, 28.5% and 100% respectively for the UASB 2, as for the production of biogas, the average production was for the UASB 1 were 0.544

/kg.COD and 1.568

/kg.COD for the UASB 2. The results showed that UASB 2 is better than UASB 1. The overall removal efficiency of the two systems during the applied phases was good, and most of the time it met the sewage network drainage standards. The results of the research lead to future directions in the framework of research and development in anaerobic treatment to achieve optimal utilization of biogas as an alternative energy source and reduce the load of organic pollution in the receiving environment as well as avoid the deterioration of sanitation facilities.