Bridging the Gap Between Urban Waste Management and Valorization Through Ratio Modelling and Windrow Co-composting of Municipal Organic Waste, Chicken Litter and Palm Kernel Fiber

Diverting municipal organic waste (MOW) from landfills through composting extends landfill lifespan while presenting an opportunity for waste valorization toward a circular economy. However, the conundrum of low compost quality, slow degradation rates, and odor in final composts makes commercial compost production unattractive. This study aims to contribute empirical evidence to improving compost quality by co-composting MOW with chicken litter (CL) and palm kernel fiber (PK). Using ratio modeling, eleven (11) pyramidal composting piles were made and assessed over an eight-week open windrow composting process. After week eight, compost samples were collected from the top, middle, and bottom of the piles and analyzed for macronutrients, heavy metals, and maturity using Atomic Absorption Spectroscopy (AAS) and the Germination Index (GI), respectively. Compost quality was compared to the European Union (EU), Food and Agriculture Organization (FAO), and French Association of Standardization (AFNOR NF U44 − 051) standards. From the findings, some compost piles had a GI of 50% or higher, indicating maturity for seed germination. All piles achieved < 2 mg CO2.C/g organic carbon/day stability. Except for Pile 3, all piles fell below the 0.5% phosphorus standard. Cadmium and nickel exceeded the permissible limits, while zinc and copper were within acceptable thresholds. Some piles met the allowable limits for heavy metals such as Zn, Cu, and Pb. Pile 3, with MOW and CL blends of 1:2, had superior compost quality and was thus most suitable for agricultural purposes. Scaling up such blends provides promise toward waste reduction, valorization, and a circular economy.