Abstract
The improper disposal of olive mill wastewater (OMW) poses a substantial environmental challenge for wastewater treatment plants (WWTPs) in the Gaza Strip. This study examines the impact of OMW on WWTPs facilities. Samples were collected from both olive mills and WWTPs across the Gaza Strip and analyzed for key biological wastewater parameters: Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD), phenols, oil and grease, and Total Suspended Solids (TSS). The findings reveal that the olive oil production process generates significant quantities of pollutants, including 3374.76 tons of COD, 797.55 tons of BOD5, 1.33 tons of phenol, 184.42 tons of oil and grease, and 1204.99 tons of TSS. During the olive harvesting season, there was a notable increase in influent pollutant levels. The Gaza Central WWTP recorded the highest levels, with BOD at 1382 mg/L, COD at 3040 mg/L, and TSS at 1810 mg/L. This spike is attributed to the high concentration of olive mills in the area. Conversely, the North Gaza WWTP, which serves a region with fewer olive mills, reported lower pollutant values: BOD at 760 mg/L and TSS at 933 mg/L. By the end of December, influent pollutant levels returned to normal domestic sewage ranges, indicating that the impact of OMW is temporary and closely associated with the olive harvesting season and related activities.