pH drops in the aerobic tank
Thread Content
Previously, the pH was around 7.5; now it has dropped to around 6. Adding liquid alkali and soda ash hasn’t helped improve it, and there’s no change in the water inlet quality either. Everyone, please give me a solution. Thank you, it’s urgent
Alkali needs to be added because microorganisms consume alkali during nitrification. The solution is to add a small amount of lime or compound alkali before the biochemical treatment. As the weather and temperatures rise, microorganisms reproduce more rapidly, which means their biochemical efficiency increases.
A decrease indicates that you have handled the situation well; add more alkali, up to 7.5 is sufficient
1. The impact of low pH in the aerobic stage on activated sludge； In the aerobic stage, when the pH is below 6, an acidic odor can be detected at the surface of the activated sludge system; the treatment efficiency drops significantly, and the activity of protozoa decreases. It is recommended to check whether the above phenomena exist and whether the measurements are inaccurate ； 2. Factors affecting the low pH in the aerobic stage: 1) High ammonia nitrogen levels in the wastewater lead to a rapid nitration process in the aerobic stage, which results in a low pH of the effluent from this stage; however, the pH does not drop below 6.5, as nitration stops when the pH approaches 6.5 ； 2) The low pH of the incoming water leads to a low pH in the aerobic zone; this is the main reason ； 3) Insufficient aeration in the aerobic stage leads to anaerobic or partial anaerobic conditions, and hydrolytic acidification results in a low pH level ； 4) Inaccurate measurements or unrepresentative sampling. Please check against the factors that could cause interference; if the problem is resolved, we would appreciate it if you could provide feedback.
I agree with the view from the fourth floor; based on the poster’s description, I personally think it’s more likely that the ammonia nitrogen level in the water is high or that aeration is insufficient. Especially now that summer has arrived, if the water temperature rises significantly, it is normal for the utilization rate of dissolved oxygen to decrease; moreover, a decrease in pH is quite common when combined with an improved nitration process.