study of sbar capability in petroleum wastewater treatment

petroleum water pollution and its hazardous substances are significant threat to the environment and human health. due to high levels of these compounds, various physical properties and costly physicochemical treatment technologies, economic and environmental methods such as biological treatment are required for treating these compounds. in this way sbar system with aerobic granules was used in 6-hour cycle. during 120-day, concentration of cod and relative tph was increased to 500 mg/l and 115 mg/l, respectively. by formation of granules, removal efficiency increased significantly. so that removal of cod and tph, was never less than 87.3% and 88%. granules were brown and their size was in the range of 5-13 mm. granulation ratio and moisture content of granules was 97.6% and 92%, respectively and their velocity was in the range of 3-3.32 cm/s, which was higher than flock's velocity. results showed that granulation is an efficient and flexible technology for full-scale treatment of pollutants which improves characteristics of the system and decreases the duration of sedimentation in a cycle and consequently reduces treatment time.