Evaluation of Household Food Waste Co-composting with Biochar

Abstract

The rapid accumulation of household food waste poses an environmental challenge, requiring efficient decentralised processing strategies to reduce landfill reliance. This study evaluates the co-composting of household food waste through Bokashi fermentation with biochar integration. Specifically, it investigates how different compost feedstock (orange–banana, OB; and watermelon rind–pak choi, WPC), biochar amendment and planting method affect: (1) compost physicochemical characteristics, and (2) early plant growth. Moisture and pH are monitored throughout composting, followed by 21-day red spinach growth trials using three planting methods: (1) standalone compost, (2) compost layered beneath planting media, and (3) compost mixed with planting media. Biochar reduces moisture content during compost maturation, while both compost formulations reach pH values indicative of compost stabilisation. For the OB compost, biochar increases the average seedling height from 2.03–2.40 cm to 3.43–3.49 cm. The study demonstrates the potential of Bokashi composting for sustainable food waste valorisation and resource recovery.