Rotary Drum Composting of Organic School Wastes and Compost Valorization

Inappropriate waste disposal imposes significant health risks in densely populated urban environments and schools, necessitating sustainable waste management. Therefore, a study was carried out at Al-Jazaer School, Kuwait, to evaluate rotary drum composting (RDC) of organic school waste comprising used paper, dry leaves, and vegetable food wastes in a 1:4:20 ratio. Feedstock comprising 42% organic school wastes, 42% horse manure, and 16% sawdust produced mature compost with a C:N ratio of 20.55 on the 43rd day of composting. Distinct mesophilic, thermophilic, cooling, and curing phases were observed during composting. Mature compost recorded a moisture content of 54.3%, pH 8.56, EC of 2.71 mS/cm, total nitrogen of 0.77%, total organic carbon of 18.25%, carbon content of 15.86%, and sulfur content of 0.14%. Soilless growing media comprising peat moss, perlite, and rotary drum compost in three proportions (1:1:1, 1:1:2, and 1:1:3), and peat moss, perlite, and commercial organic compost in a 1:1:3 ratio were evaluated for greenhouse vegetable production. The performance of cucumbers (Cucumis sativus cv. Ramos) raised in the lowest proportion of in-house prepared rotary drum compost (1:1:1 ratio) was comparable with that raised in the highest proportion of commercial compost (1:1:3). The study revealed the potential of RDC for decentralized sustainable waste management at the small-community scale and the suitability of compost from school wastes for soilless culture.