【Weekly Topic】--The impact of total nitrogen on the operation of aerobic tanks (10 points for good answers, 30 points for satisfactory answers)
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Total nitrogen includes organic nitrogen, ammonia nitrogen, and nitrate nitrogen; when the nitrogen concentration in the aerobic tank is high, it can cause the activated sludge to disintegrate and lose its flocculence, leading to operational problems in the activated sludge tank and excessive levels of pollutants in the effluent； This phenomenon can also occur when the C/N ratio is too low ； So at what level of nitrogen, and when is the C/N ratio below what value, will this phenomenon occur? What measures can be taken to mitigate sludge disintegration when nitrogen levels are high or the C/N ratio is low?
Based on personal experience, for the aerobic tank in the activated sludge process, when the C/N ratio is at least 10:1, its impact on the operation of the activated sludge is minimal and can be disregarded.
Keeping the C/N ratio within the range of (15-20):1 allows for the use of biochemical treatment; if it’s too high, biochemical treatment should be combined with chemical methods
It is generally believed that when the ratio of BOD5 to TKN in wastewater is between 5 and 8, the carbon source in the wastewater is considered sufficient, and there is no need to consider adding an external carbon source. Incomplete nitrification-denitrification is a major cause of active sludge bulking under low C/N conditions, which leads to sludge disintegration and flocculation breakdown; a real-time control system can be used to automatically optimize the dosage of added carbon source.
This post was last edited by zhaolijun on 2015-8-29 at 16:50. Incomplete nitrification and denitrification are the reasons for active sludge bulking and flocculation breakdown in low C/N conditions
This post was last edited by zhaolijun on 2015-8-29 at 16:50. The alumina content in solid polyaluminum chloride is generally 28%, while it is 10% in the liquid version. The dosage should be determined through experiments for the best results. Aeration stirring is completely feasible
Under special conditions of extremely high ammonia nitrogen levels and severe carbon source deficiency, preventing the DO level in the reaction tank from becoming too high helps to maintain a stable sludge concentration in the tank. To achieve simultaneous nitrogen removal, maintaining DO within the range of 0.4–1.5 mg/L and ensuring an adequate aeration time (3–5 hours) can mitigate the adverse effects of high ammonia levels and low carbon sources.