Influence of Nitrite on the Removal of Organic Matter and Manganese Using Pilot-Scale Biofilter: A Kinetic Study

Nitrite produced during ammonia oxidation can inhibit the activity of microorganisms. To provide guidance for the optimization and design of a biofilter, a pilot-scale biofilter was established to investigate the influence of nitrite on organic matter and manganese removal and on the kinetics. The results demonstrated that CODMn, ammonia, and manganese in effluent were 2.77, 0.034, and 0.026 mg/L in the steady phase, respectively. Organic matter and manganese removal were affected by nitrite during the start-up process, as well as in the ammonia increasing process. When ammonia increased from about 0.5 to 1 and 2 mg/L, organic matter, and manganese removal were affected at 4 and 3 days and 6 and 5 days, respectively. When organic matter, ammonia, and manganese in the influent were 6.27, 2.07, and 1.19 mg/L, respectively, organic matter, ammonia, and manganese oxidation all followed a first-order kinetic rate. The k-value was 0.0268, 0.268, and 0.216 min−1, and the half-life time was 24.236, 2.583, and 3.202 min, respectively. The influence of nitrite on the structure of microbial communities in the biofilter will be investigated in the future.