Nitrogenous Wastewater Treatment by Activated Algae

A biological treatability study by activated algae process was performed with synthetic wastewater containing a high concentration of nitrogen. It was found that the wastewater could be processed at all nitrogen removal rates. The yield coefficient and decay coefficient for heterotrophic bacteria were 0.06 (COD basis) and $0.019{\mathrm{day}}^{-1}$ (COD bases) respectively. The yield coefficient and decay coefficient for nitrifiers were 0.06 and $0.02{\mathrm{day}}^{-1}$ respectively. ${\mathrm{NH}}_{4-}^{+}N$ seemed to inhibit bacteriological growth as the yield coefficients values were significantly lower. Nitrification was observed at all the nitrogen loadings. Diffusion of ${\mathrm{NH}}_3$ into the atmosphere was the dominant mechanism of nitrogen removal. The results demonstrated a symbiotic relationship between algae and bacteria.