NH3-N ​​reduction rate of stripped sour water

The NH3-N ​​reduction rate of stripped sour water is low, if we consider the TKN of  stripped sour water, the NH3-N of effluent is higher than influent.   Why does the NH3-N of stripped sour water not react to NO3-N? Is the cresol of stripped sour water to inhibit the microorganism, or the nutrient content of  stripped sour water too poor to active the AOB/NOB, or others we still not know.