Co-composting of sawdust with food waste: effects of physical properties on composting process and product quality

Abstract

Sawdust and food waste have been part of solid organic waste causing great environmental pollution. Composting is a popular utilization method of converting waste like sawdust and food waste to sanitized and stabilized soil amendment. Unfortunately, many composting systems failed due to a dearth of information as a result of little or no scientific research focused on the effects of the physical properties of composting materials on the composting process. To fill this knowledge gap, three composting experiments of food wastes mixed with sawdust at ratio 20:80, 30:70, and 40:60 and compacted to different initial bulk densities of 15, 20, and 25 kg/m3 respectively was carried out to explore the effect of physical properties on composting of sawdust with food wastes. Physicochemical parameters monitored include bulk density; porosity; particle density, temperature, moisture content; pH, and electrical conductivity (EC). The highest temperature (65.3 oC) was recorded by trial 3 while trial 1 recorded the lowest temperature (49.3 0C). Among trials 1, 2, and 3, the maximum pH (9.2) and EC (5.1 mS/cm) were observed in compost trial 3. Additionally, the lowest pH (5.3) and EC (1.4 mS/cm) was observed in trial 1. Trial 3 had the highest percentage finest and lowest fibrosity content. A significant increase in bulk density, porosity, and particle density was observed in the three compost trials. The compost’s bulk density of (25 kg/m3) in trial 3 was observed to attain maturity and stability as compared with trials 1 and 2.