Pengekstrakan Amonia-Nitrogen dan Ortofosfat daripada Efluen Kilang Sawit dalam Bentuk Struvit

Abstract

Ammonia-nitrogen (NH<sub>3</sub>-N) and orthophosphate (PO<sub>4</sub><sup>3-</sup>) contain in palm oil mill effluent will cause toxicity to aquatic life and polluted water source. However, these substances could be use as fertilizer for plant. Nitrogen and phosphorus are the mandatory nutrient source for the plant growth. This study studied the effect of pH and magnesium weight on the effectiveness of the extraction of ammonia-nitrogen (NH<sub>3</sub>-N) and orthophosphate (PO<sub>4</sub><sup>3-</sup>) from palm oil mill effluent (POME) in the form of struvite (MgNH<sub>4</sub>PO<sub>4</sub>•6H<sub>2</sub>O). The effect of pH on percent removal of NH<sub>3</sub>-N and PO<sub>4</sub><sup>3-</sup> from POME was studied by manipulating the pH of POME at constant the weight of magnesium chloride (MgCl<sub>2</sub>). Meanwhile, the effect of MgCl<sub>2</sub> on the percentage removal of NH<sub>3</sub>-N and PO<sub>4</sub><sup>3-</sup> from POME was studied by manipulating the weight of MgCl<sub>2</sub> at constant pH of POME. The concentrations of NH<sub>3</sub>-N and PO<sub>4</sub><sup>3-</sup> were determined using spectrophotometers and struvites were characterized using fourier-transform infrared (FTIR). This study showed that pH is an important factor in the extraction of NH<sub>3</sub>-N and PO<sub>4</sub><sup>3-</sup> ions in the form of struvit. pH 11.5 is the optimum pH to achieve the effective extraction process of NH<sub>3</sub>-N and PO<sub>4</sub><sup>3-</sup> from POME in the form of struvit. Addition of the MgCl<sub>2</sub> did not have a significant effect on the extraction process because POME contained sufficient magnesium ions for the extraction process. The highest NH<sub>3</sub>-N and PO<sub>4</sub><sup>3−</sup> removal was attained at pH 11.5 with the addition of 0.5 g MgCl<sub>2</sub>. 93.72% NH<sub>3</sub>-N and 86.15% PO<sub>4</sub><sup>3-</sup> were removed from POME in struvit extraction process. The resulting struvit yield was also identified through FTIR analysis by the existence of O-H bond, N-H bond, and P-O bond.