Performance of Chlorella vulgaris for the removal of ammonia-nitrogen from wastewater

Abstract

In the present investigation, the efficiency of Chlorella vulgaris (C. vulgaris) was evaluated for the removal of ammonia-nitrogen from wastewater. Eight different wastewater samples were prepared with varied amounts of NH4-N concentrations from 15.22 to 205.29 mg/L. Experiments were conducted at pH 7.5 ± 0.3, temperature 25°C ± 1°C, light intensity 100 μE/m2/s, and dark-light cycles of 8-16 hr continuously for 8 days. From the results, it was found that NH4-N was completely removed by C. vulgaris, when the initial concentration was between 5.22-25.24 mg/L. However, only 50% removal was obtained when the NH4-N concentration was 85.52 mg/L, which further decreased to less than 32% when the NH4-N concentration exceeded 105.43 mg/L. The further influence of nitrogen on chlorophyll was studied by various NH4-N concentrations. The maximal value of chlorophyll a (Chl a) content was found to be 19.21 mg/L for 65.79 mg/L NH4-N concentration, and the maximum specific NH4-N removal rate of 1.79 mg/mg Chl a/day was recorded at an NH4-N concentration of 85.52 mg/L. These findings demonstrate that C. vulgaris could potentially be employed for the removal of NH4-N from wastewater. © 2013 Korean Society of Environmental Engineers.