Effect of Aeration rate on Wet- refuse-derived fuel Biodrying process for increasing Heating value and Water content reduction

Mechanical Biological Treatment (MBT) at On-Nuch waste transfer station is used for waste treatment generated from Bangkok and Metropolitan Area. It can separate organic waste, recycle material, and solid waste. This solid waste can be considered for converting into solid recovered fuel because it comprises more than 50% plastic and 20% biomass. However, due to its higher water content and lower heating value, this material was called wet- refuse-derived fuel (Wet-RDF). Besides, the biodrying process has been used for water removal by activating microorganism's activity. This process encourages heat production and vapor release. However, aerated supply is necessary to determine the optimal biodrying operation. Therefore, this study investigated the aeration rate effect on the Wet-RDF biodrying process. This study was performed on the 0.375 m3 square-steel lysimeters with 0.5 m wide and 1.5 m high. The continuous negative ventilation has varied the rates to 0.3, 0.5, and 0.6 m3/kg/day. The operation time was set to 5 days for the experiment. Feedstock's initial moisture content and low heating value were 44.91% and 3,207 kcal/kg, respectively. The measured daily temperature represents the self-heating value in the process for the range of 20–63 °C, and its peak was found during days 2–4. The average inner and exhaust gases as bioactivity produced peaked on day 3 at 4% carbon dioxide and 14-16% oxygen concentrations. The final composition decreased both degradable material and non-degradable material by 2%. The optimum aeration rate was o.6 m3/kg/day because of higher water content reduction and lower organic loss. In this regard, it provides the optimum biodrying index of 0.171, which raises water reduction while remaining the carbon source in terms of organic reduction. Also, 4,901 kcal/kg of low heating value and 36.6% moisture content were provided for the final product. According to the RDF-3 criteria requirement for local cement production, the optimum aeration rate was accepted only in terms of low heating value.