Experimental investigation on the effects of aeration patterns in the solar greenhouse biodrying system

Biodrying is a solid waste pretreatment method that reduces landfill dependency, enhances recycling efficiency, and increases waste-to-energy potential. This study investigated the effects of aeration patterns on the performance of the solar greenhouse biodrying for the moisture reduction. Rectangular reactors (52 × 52 × 77 cm) were used to evaluate among positive, negative, and passive aeration at varying airflow rates (4-15 L/min) under different environmental conditions. A mass balance model was applied to analyze water and solid mass changes across six experimental trials. Performance indicators, including the biodrying index (BI), temperature integration (TI), and air efficiency (AE), were applied to demonstrate the interplay of aeration directions, airflow rate, and inlet air temperature on biodrying efficiency and heat retention. Results revealed that aeration direction and airflow rate strongly influenced temperature distribution, moisture removal, and solid preservation. Positive aeration promoted upward heat stratification, enhanced moisture evaporation, and minimized leachate formation. Also, positive aeration at 8 L/min identified as the optimal aeration strategy for high biodrying efficiency. Negative and passive aeration enhanced organic degradation and heat retention within the waste piles but led to higher leachate production and less efficient moisture removal. This study is novel in providing a comprehensive comparison of all aeration direction patterns in the solar greenhouse biodrying system, quantifying their effects on mass change, biodrying efficiency, and offering recommendations for improving waste pretreatment under various weather conditions.