Abstract:
This research was to study the treatment of synthetic oily wastewater, 5,000 mg/l palm oil, and anionic surfactant (Sodium Dodecyl Sulphate, SDS) by fibrous bed coalescer, and the possibility of using the cheaper and more available material as coalescing bed. The concept of multi stage bed configuration, chemical addition, and induce air flotation (IAF) were applied in order to improve the conventional coalescer efficiency. The results showed that the plastic (aquarium) fiber, having contact angle of 87.88 degree, was more hydrophobic than stainless steel fiber. Bed height and wastewater flow rate were found to effect the overall efficiency of conventional coalescer. The highest COD removal efficiency (44.37%) was obtained by using 3.5 cm of bed height and 5 LPH flow rate. Combining various improving methods with the conventional coalescer in batch operation showed that the highest removal efficiencies obtained with chemical addition, multi stage bed configuration, and IAF processes were 62.2%, 52.46%, and 44.59%, respectively. The optimal operating condition based on various methods was applied to the continuous operation. The treatment efficiencies were decreased about 30% compared to batch operations because of lesser oil droplet interaction time. The recirculation of wastewater into reactor was found to increase the efficiencies by 10%. In conclusion, the operating or detention time is the most important parameter for controlling the treatment efficiencies in coalescer process.