ผลของอัตราส่วนเวลากักแอนแอโรบิก/แอโรบิกที่มีผลต่อ ประสิทธิภาพในการบำบัดน้ำเสียสังเคราะห์แป้งมันสำปะหลัง โดยกระบวนการแอกทิเวเต็ดสลัดจ์ชนิดเอสบีอาร์แบบแอนแอโรบิก/แอโรบิก / ธนินทร์ ปัญญาภิญโญผล = Effect of anaerobic/aerobic retention time ratio on the efficiency of synthetic tapioca wastewater treatment by an anaerobic/aerobic SBR activated sludge process / Thanin Panyapinyopol
The effect of the ratio of anaerobic/aerobic retention time on the COD removal efficiency was studied by using 10 L SBR reactors with an influent volume (Vf) : retaining volume (V0) ratio of 1:9 and 12-hours cycle time. A tapioca starch wastewater was synthesized to have COD concentration in the range of 8,256-9,090 mg/l (BOD 6,200-6,800 mg/l). The experiments consisted of 2 parts; firstly, three anaerobic/aerobic retention time ratio of 8/3, 5.5/5.5 and 3/8 hours were used at 7 days sludge age, from which the COD removal efficiencies at steady state and F/Mv ratio of 0.21-0.26 day-1 were 98.7, 99.2, and 99.4 percent, respectively. Most of COD removal occurred in the anaerobic condition. Secondly, the anaerobic/aerobic retention time ratio of 5.5/5.5 was selected for a subsequent study at sludge age of 3 and 5 days. During the steady state, the COD removal efficiencies was 98.9 percent for both sludge age, at F/M ratio of 0.47 and 0.34 day-1, respectively. The results shown that the anaerobic/aerobic retention time ratio of 5.5/5.5 at sludge age of 7 days was considered to be the most suitable operating condition based on sensitivity to sludge bulking and operating cost, and also indicated that if this process was properly operated, it could decrease sludge bulking problem which might be caused by substrate like tapioca starch. The sludge volume index (SVI) of this experiment was in the range of 26-32 ml/g.
