The impact of pH value on the operation of the A/O process
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The company’s wastewater is chemical wastewater, and the biological treatment process used is the A/O process. Recently, it was observed that the pH level in the anoxic zone remained around 7.2; the pH of the water entering the anoxic zone was 7.5, while the pH in the aerobic zone was 7.8. All other parameters were normal. What could be the reason for the low pH in the anoxic zone?
Are the pH measurements and sampling points normal?
The sampling location is fine; there has been no change； The measurements have also been verified repeatedly, and there are no issues with them.
In general, the pH level in an anoxic tank increases due to denitrification; if it does not increase, it may be because there are no denitrifying bacteria or the denitrification process has been inhibited.
Are there any data on BOD and total nitrogen? If the B/N ratio is less than 4, denitrification will be inhibited and fail.
Additionally, the concentration of nitrate salts is also one of the key parameters. What level of dissolved oxygen do you maintain in your O tank? If the dissolved oxygen level is low, the nitrification process slows down, and without nitrate salts present in an oxygen-deficient environment, denitrification does not occur.