PRODUCTION OF BIOGAS AND NUTRIENT-RICH SLURRY FROM FOOD WASTE DIGESTION IN LAB-SCALE DIGESTER

Azini Amiza Hashim1*, Siti Fatimah Sa’ad1, Kartikah Sellappan1

1 Department of Petrochemical Engineering, Politeknik Tun Syed Nasir Syed Ismail

 



ABSTRACT

In Malaysia, about 16,688 tonnes of food waste are generated daily, and nearly 80% of the generated food waste is still disposed of at the landfill despite its biodegradable characteristics. The disposal of food waste in landfills could contribute to global warming as the food waste’s decomposition produces harmful greenhouse gases, including methane, that escape directly into the atmosphere. The major factors contributing to food waste are the negligence of individuals and a lack of awareness of the impact of food waste on the environment. This study proposes an environmentally friendly approach for producing biogas and nutrient-rich slurry by utilizing three different types of food waste, including mixed food waste, fruit waste, and vegetable waste, in the lab-scale digester. Three types of food waste were mixed with cow manure and left in three separate digesters for one month. The presence of biogas was determined by observing the Bunsen burner flame at the pipe end. The physical and chemical characteristics of the slurry, such as temperature, density, turbidity, pH, total dissolved solids, and total suspended solids, were also tested. Apart from that, Ultraviolet-Visible (UV-Vis) spectroscopy was carried out to identify the nutrient and functional group composition present in the slurry. The findings indicated that a small amount of biogas was successfully produced from the anaerobic digestion of food waste. Besides, anaerobic digestion slurry produced from vegetable waste has potential as fertilizer due to its high concentrations of nitrogen (N), phosphorus (P), and potassium (K) at 290.45 ppm, 179.66 ppm, and 162.64 ppm, respectively. Therefore, the utilization of food waste to produce biogas and nutrient-rich slurry could act as a green alternative to reduce the environmental impact of improper food waste disposal. 


Keywords:

Biogas Food Waste, Anaerobic Digestion Slurry Slurry Characterization