Performance and microbial community profiles in pilot-scale biofilter for the simultaneous removal of ammonia, iron and manganese at different manganese concentrations

To accelerate extensive application of biological manganese removal technology, a pilot-scale biofilter for ammonia, iron and manganese removal was constructed to investigate the removal performance and microbial community profiles at different manganese concentrations. When manganese in influent increased from 1 to 10 mg/L, the pollutants were completely removed. Ammonia and iron was slightly changed along the filter depth, while manganese obviously increased. In 0 m of the filter depth, the abundance of Gallionella (iron oxidizing bacteria, IOB) increased, while Crenothrix (IOB) decreased. The abundance of Gallionella (manganese oxidizing bacteria, MnOB) in 0.4 and 0.8 m increased to 16.82% and 12.37%, respectively; and Crenothrix (MnOB) in 0.8 m increased to 19.95%, but decreased to 25.08% in 0.4 m. The abundance of ammonia oxidizing bacteria (AOB, Nitrosococcus) decreased in 0.4 and 0.8 m. The biofilter presented a high ability to remove manganese, and had a broad application prospect.