| dc.description.abstract | Activated Sludge Process and its modified methods had used very widely. The daily wastewater quality would vary with time or in different regions. Generally, the strategies treating the dynamic inflow in wastewater treatment plants were used to set up equilibrium basins, design by safe factors and long-term experiences as modified operations and control rules. However, these strategies were not efficient methods or increased the capital cost. Therefore, it is a test for the efficiencies and the optimal operations of BNR process（Biological Nutrient Removal Process） during the dynamic inflow. TNCU-3 process （Taiwan National Central University-3） is used in this research.
It is controlled that SRT was 10 days, inflow quantity Q was 240ml/min, COD was 300mg/L, TN was 40mg/L, TP was 5mg/L and HRT was 9.5 hours in steady state. The six runs were operated at Q1:Q2:Q3 was 1:0:0:0, 0.9:0.1:0, 0:8:0.2:0, 0.7:0.3:0, 0.8:0.1:0.1 and 0.7:0.2:0.1 and the return sludge rate Qr was 0.5Q. The effluent SCOD was less than 20mg/L and the removal efficiency more than 94％. The effluent phosphate and phosphorus weren’t detected. The suspended solid was about 6 to 14 mg/L. The removal efficiency of total nitrogen was about 69.2% to 76.4%. All of the nutrient removal efficiencies in TNCU-3 were higher than other BNR processes.
It is controlled that SRT was 14.6 days, inflow quantity Q was 80 to 240ml/min, COD was 100 to 300mg/L, TN was 25 to 40mg/L, TP was 3~5mg/L and HRT was about 9.5 to 14 hours in dynamic operations. 6 step-feed runs were separated to Qr:Q was 0.5 and 0.25. In summary 12 runs operated and monitored the treatment qualities by computer. The computer monitoring results as followings: ORP was -50 to 370 mV in anaerobic zone, pH was 6.3 to 6.9 anaerobic zone, DO was 1.5 to 4（mg/L）in aerobic-1 zone、effluent COD was 4 to 15（mg/L）, effluent nitrate was 5 to 14（mg/L）, effluent pH was 7 to 7.5 effluent SS was 2 to 10（mg/L） and the return suspended solids was 2800 to 6800（mg/L）。
In 24 hours batch experiments the total F/M of the process was 0.15 to 0.18. Average MLSS was about 1,600 to 2,000mg/L and less than steady-state. It was influenced by F/M in anaerobic zone. When the F/M was high in anaerobic zone the average MLSS would be high in whole process. MLSS was diluted 200 to 400 mg/L and was obviously in two step-feed. Effluent COD in each run was about 4 to 12 mg/L and its removal efficiency was higher than 93%. This result was similar to steady-state. Effluent nitrate was 5 to 11 mg/L and its removal efficiency was 65 to 84%. It was found when the C/N was high in anoxic zone then the remaining nitrate in aerobic zone would be low if the control volume was anoxic zone and aerobic zone. When the C/N was controlled between 4 to 8 in 1st anoxic zone the remaining nitrate would be between 5 to 8 mg/L in 3rd aerobic zone. When the C/N was controlled between 3 to 5 in first 2nd anoxic zone the remaining nitrate would be between 5 to 7 mg/L in 4th aerobic zone. The removal efficiency of phosphorus is obviously less than steady-state. Effluent phosphate was about 0.03 to 0.7 mg/L in dynamic operation and its removal efficiency is between 68.2 to 98.7%. The optimal efficiency of nutrient removal was run-0.7:0.2:0.1 in the research. | en_US |