With the increase of PCP concentration, the numbers of AOB in both types of sludge had no obvious change(p>0.05). The numbers of AOB had no obvious correlation with ammonia removal (p>0.05).

• PCP浓度与氨氮的去除率成负相关；但不影响氨氧化细菌的数量(p>0.；05)；氨氧化细菌的数量与氨氮的去除也无直接正相关关系(p>0