Anaerobic digestion of organicwaste in UMS campus for resource recovery andwaste reduction

Abstract

Phosphorus, a limited non-renewable mineral source can be recovered from food waste in a form of struvite, a slow-release fertiliser. This study was conducted to determine the physical and chemical characteristics of food wastes collected from Tun Mustapha Residences café of Universiti Malaysia Sabah (UMS), to recover phosphorus and reduce the amount of food waste produced. Anaerobic digestion was used to degrade the organic solid waste and solubilise nutrients, which was performed at controlled conditions (pH 6.8-7.2; 37 °C) for 15 days. The results showed that the total solids and volatile solids for the raw sample were high, 42.9% and 94.3%, respectively; due to high solid and organic content. The concentration of magnesium (Mg2+), ammonium (NH4+) and phosphate (PO4 3-) after digestion were 114.00 mg/L, 73.87 mg/L and 554.04 mg/L, respectively. The phosphorus can be potentially recovered in the form of struvite with 136 g struvite/g food waste. After anaerobic digestion, total solids and volatile solids were degraded with 40.11% and 76.51% reduction, respectively. Throughout this study, it can be suggested that food waste is naturally high in nutrient content that can be a source for phosphorus recovery in which the waste volume can be reduced after performing anaerobic digestion.