This study aims to evaluate the efficiency of wastewater treatment plant and
the quality of treated wastewater for irrigation purposes at Sirte city in Libya, during November
2012. Samples of wastewater were collected before and after treatment at 8 am and 4 pm of the
each day of November. The official methods were followed in collection and analysis of the
wastewater samples. The average values of purification efficiency were varied across the
measured parameters, where as the lowest and highest values of purification percentage were
3.16 % and 33.45%, recorded for phosphorus (P) and bicarbonates (HCO3), respectively. On the
other hand, the values of pH and chloride were increased by 5% and 33% after treatment,
respectively. The most parameters of treated wastewater were found to conform to FAO
standards for irrigation water. However, the electrical conductivity (EC), chloride (Cl), sulfate
(SO4), chromium, manganese and molybdenum were found exceeding the severe restriction
zone according to FAO standards. The study concluded that using of treated wastewater of Sirte
plant for irrigation purposes need appropriates soil–water–crop management strategies as to be
used safely.