The use of immobilized microalgal bead concentrations in the removal of ammonium nitrogen from synthetic wastewater

Abstract

Removal of chemical pollutants has been important in the treatment of wastewater. The effect of Chlorella vulgaris (microalgae) on the removal of ammonium nitrogen (NH₄⁺) in synthetic wastewater (wastewater prepared in the laboratory) was investigated. C. vulgaris cells were immobilized in calcium alginate beads to allow diffusion of nutrients but retention of the cells. Concentration of C. vulgaris cells used to treat wastewater were equivalent to 20 g/l, 40 g/l and 80 g/l of wastewater and treatment was under laboratory conditions at 25±2°C. C. vulgaris was effective in the removal of NH₄⁺ from wastewater; at  the end of 24 hours of treatment, there was reduction in the initial concentration of NH₄⁺ by 78% for 20 g/l. For 40 g/l treatment, there was 97% reduction in NH₄⁺ and 91% reduction for 80 g/l treatment. After 43 hr of treatment, there was further reduction in NH₄⁺ for 20 g/l (86%), and 80 g/l (93%) but 40 g/l (97%) remained constant. The concentration of C. vulgaris that showed the best activity in removing NH₄⁺ -from wastewater was 40 g/l.

Keywords: Microalgae, immobilize, microalgae, bead concentrations, ammonium nitrogen