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4128089 
Journal Article 
Influence of nitrite on the removal of Mn(II) using pilot-scale biofilters 
Cheng, Q; Nengzi, L; Xu, D; Guo, J; Yu, J 
2017 
7 
3 
264-271 
WOS:000405065700002 
Two pilot-scale biofilters were used to systematically investigate the influence of nitrite on biological Mn(II) removal. Gibbs free energy change (Delta G) of the redox reaction between MnO2 and NO2- was 122.28 kJ mol(-1) in 298 K, suggesting that MnO2 could not react with NO2-. When nitrite in the influent was increased from 0.05 to 0.5 mg L-1, manganese oxides did not react with nitrite in anaerobic conditions; nitrite was quickly oxidized and biological Mn(II) removal was slightly affected in 2 h in aerobic conditions. When nitrite was accumulated in the biofilter by increasing ammonia concentration, nitrite existed for more than 3 d and biological Mn(II) removal was affected in 3 d. When Mn(II) and ammonia in the influent were about 2 and 1.5 mg L-1, respectively, both of them were completely removed and the oxidation-reduction potential was increased with the depth of the filter from 16 to 122 mV. Biological Mn(II) removal followed the first-order reaction, and the k-value was 0.687 min(-1). 
biofilter; groundwater; kinetics; manganese removal; nitrite