paper 1:Operational Boundaries for Nitrite Accumulation in Nitrification Based on Minimum/Maximum Substrate Concentrations That Include Effects of Oxygen Limitation, pH, and Free Ammonia and Free Nitrous Acid Inhibition
author：SEONG JUN PARK , WOOKEUN BAE ,AND BRUCEE . RITTMANN
paper 2:Nitration Processes of Acetaminophen in Nitrifying Activated Sludge
author：SERGE CHIRON , ELENA GOMEZ , AND H´ELE`NE FENET
