ESTABLISHMENT OF AN ANAEROBIC AMMONIUM-OXIDIZING CULTURE IN CONTINUOUS FLOW TREATMENT WITH NON-WOVEN BIOMASS CARRIER

Acclimation of biofilm cultures treating groundwater in Kumamoto, Japan, capable of anaerobic ammonium oxidation (Anammox) has been ongoing in our laboratories. Biofilms have exhibited a distinctly red color and simultaneous ammonium and nitrite removals under autotrophic, anoxic conditions, which are characteristics of anaerobic ammonium-oxidizing cultures. In this research, a maximum ammonium removal rate of 27 mg N/L/h was achieved, corresponding to a specific removal rate of 0.019 mg N/mg/h. Total-nitrogen removals were a factor of 1.9 over that of only ammonium, which is sufficiently high for industrial applications. For characterization of the bacterial composition of the biofilm, partial 16S rDNA sequences were amplified by PCR. Two of the phylotypes (consisting of 9 of 14 clones) were affiliated with Zoogloea and Aquaspirillum although their functions in the biofilm were not determined. Another sequence (5 of the 14 clones) had a close match to a planctomycete reported to have Anammox capability. These results demonstrate that an attached growth process can be effectively used to develop a continuous flow Anammox treatment process.