[3S05Aa] 21. Open Topics in Biotechnology - Part 1

3:15 PM - 3:30 PM JST(6:15 AM - 6:30 AM UTC)

[3Open-07] Closed-Loop Recycling of Food Waste through Co-Pyrolysis with Bone Meal into Nutrient-Enriched Biochar for Soil Retention and Controlled Nutrient Release

○Nadya Ramadhani Arke¹, Kuan Shiong Khoo¹ (1. Yuan Ze University (Taiwan))

Keywords:

Food waste valorization,Co-pyrolysis,Bone meal,Biochar,Controlled-release fertilizer,Nutrient-enriched biochar

Food waste has become a major environmental concern driven by inefficient resource utilization and conventional landfilling or incineration disposal practices that contribute directly to greenhouse gas emissions. Inadequate food waste management systems further exacerbate these challenges, leading to nutrient losses and soil degradation. In this context, the thermal degradation of food waste through pyrolysis offers an effective pathway for converting waste into value-added biochar, facilitating carbon stabilization while improving nutrient retention and soil amendment potential. To enhance nutrient recovery and agronomic value, bone meal enriched in calcium and phosphorus are incorporated as a functional additive, promoting the formation of Ca–P mineral phases that enables slow-release nutrient mechanistic. This synergistic approach improves biochar performance as a soil amendment and supports sustainable waste valorization within a circular bioeconomy framework. This study evaluates the influence of pyrolysis temperature (400°C, 500°C, and 600°C) on the physicochemical and morphological properties of food waste-derived biochar to identify optimal conditions for soil amendment applications. Biochar samples were characterized using elemental (CHNS) analysis, atomic ratios (H/C and O/C), pH measurement, and scanning electron microscopy (SEM) to assess surface morphology and pore structure development. Preliminary results demonstrated that pyrolysis temperature significantly affects both chemical composition and structural characteristics. Biochar produced at 500°C exhibited an optimal balance of properties, with carbon content exceeding 50%, H/C ratios of 0.64–0.68 (<0.7), and O/C ratios of 0.41–0.51 (<0.6), indicating enhanced aromaticity, carbon stability, and suitability for long-term soil carbon sequestration. SEM analysis revealed distinct morphological differences across temperatures. Microscopic analysis revealed that 500°C biochar had a well-developed and connected pore structure, which is beneficial for water retention, nutrient adsorption, and microbial activity. The biochar produced at 400°C had fewer pores, while 600°C showed pore collapse and structural damage. In addition, biochar samples were blended with bone meals at different ratios exhibited slightly alkaline pH values ranging from 7.7 to 8.5, suggesting their effectiveness in ameliorating acidic soils and enhancing nutrient availability. The combination of improved structural properties and favorable surface chemistry at 500°C also indicates strong potential for slow nutrient release behavior and enhanced interaction with soil ecosystems. Overall, biochar produced at 500°C demonstrates the most suitable characteristics, combining stable carbon structure, optimal functional groups, and favorable pore morphology. These findings highlight the critical role of pyrolysis optimization in producing high-quality biochar and support sustainable food waste valorization strategies. The integration of such systems contributes to waste reduction, resource recovery, and improved soil fertility, aligning with circular bioeconomy principles.