Inorganic nitrogen compound removal efficiency of an added initial bacterium in the biological filtration system

Abstract

The efficiency of inorganic nitrogen compound removal using Nitrosomonas sp. strain P-1 was investigated in a filtering system. Bacterial cell densities and concentrations of inorganic nitrogen compounds including ammonia, nitrite, and nitrate were determined every 4 days. Ammonia decreased immediately after treatment for 4 days and was reduced from an initial concentration of 65.75 to 17.57 mg/l during the 28-day experiment. Nitrite and nitrate increased from 0 to 0.239 mg/l and 4.292 mg/l, respectively, over this same period. Total amount of inorganic nitrogen compound removed from the filtering system was 46.91 mg/l. Result also showed that the number of ammonia oxidizing bacterium, Nitrosomonas sp. strain P-1, increased from 101 to 627 cfu/ml over the 28 days. Comparison to a control where no bacteria were added, showed a highly significant difference (P<0.01) in the efficiency of inorganic nitrogen compound removal.