Assessment of the efficiency of the wastewater treatment plant at Zawia Oil Refinery and the compliance of the treated water with Libyan standard specifications

Abstract

The efficiency of the wastewater treatment plant at Al-Zawiya Oil Refining Company was evaluated for 3 months, at the rate of a sample per month, taken from both the inlet and outlet of the plant, where the determinants of environmental pollution of the water entering the plant and the treated water and before discharging it to agricultural lands were studied These determinants included both the biological need for oxygen, the chemical need for oxygen, total dissolved solids, pH, temperature, electrical conductivity, dissolved oxygen and temperature, and it was observed that the efficiency of the plant in disposing of BOD reach 94.1% and COD  to 93.8, and in general, the plant is operating with excellent efficiency as its design capacity is 1100 cubic meters per day, and the average concentrations of COD, BOD and TDS for the samples at the outlet of the plant were 13.5, 7.3 and 1758.3 1/mg, respectively, where these concentrations were within the limits of the Libyan standard specifications for treated water, and the average dissolved oxygen at the outlet was 5.03, and the average temperatures of the treated wastewater samples were 25.5 degrees Celsius, and average.  The pH of the samples was 8.11, the temperatures and pH were within the limits of the Libyan specifications, and the average electrical conductivity of the samples at the output was 2747 si/cm, where it was within the limits of the Libyan specifications.