[Experimental study on the processes and mechanism of enhanced denitrification by addition zeolite in wastewater treatment].

Aim to enhance nitrogen removal from wastewater, addition zeolite to aeration tank was preformed. The result showed that addition of zeolite could improve the nitrification/denitrification efficiencies by comparing two phase experiment of 25 mg/L with blank and 25 mg/L with 50 mg/L, and the population of nitrifying bacteria in activated sludge increased obviously. When 25 mg/L zeolite was added into aeration tank, NH4(+) -N and TN removal increased 10% - 13% and 13% respectively, endogenous respiration rate of nitrification increased about 138%, and the population of nitrification bacteria increased about 2.2 folds. But the nitrogen removal and endogenous respiration rate of 50 mg/L enhanced indistinct comparing with 25 mg/L. These results indicated that NH4+ ion-exchange and accumulation to the interior/outer surfaces of zeolite, co-existence of aerobic and anoxic micro-environments were responsible for the enhanced denitrifying function.