Optimization of Composting Oil Palm Empty Fruit Bunches Through the Addition of Palm Oil Mill Effluent Sludge and Cellulolytic Microbial Inoculant

East Kalimantan is one of the provinces in Indonesia experiencing rapid expansion of oil palm plantations, resulting in the generation of substantial quantities of solid and liquid wastes, particularly oil palm empty fruit bunches (EFB) and palm oil mill effluent (POME). If inadequately managed, these wastes pose a significant risk of environmental pollution. However, their high organic matter and nutrient contents indicate considerable potential for conversion into organic fertilizer through composting processes. This study aimed to explore the composting performance of oil palm biomass waste using several composting treatment variations. The experiment followed a single-factor design over a 60 -day period with four treatment: EFB alone, EFB with Stardec, EFB with POME sludge, and EFB with POME sludge combined with Stardec, each replicated five times. Chemical properties analyzed included organic carbon (Walkley and Black), total nitrogen (Kjeldahl), available phosphorus (Bray), and available potassium (Morgan). The results indicated that all treatments exhibited a decrease in the C/N ratio to a range of 10–20 by day 60, reflecting compost maturity. The concentrations of nitrogen, phosphorus, and potassium generally increased across all treatments and reached their peak values on day 45. Compost weight reduction ranged from 32.5% to 39.57%, demonstrating that the decomposition process proceeded effectively and that the compost had reached a stable and mature state. The treatment combining POME sludge and Stardec resulted in the highest weight reduction, indicating that the combined application of POME sludge, microbial inoculant (Stardec) was effective in enhancing composting performance and improving compost quality

Compost · Elaeis guineensis · Green waste · Microbial inoculant · Nutrient · Organic matter · Phosphorus · Pome · Composting and Vermicomposting Techniques · Municipal Solid Waste Management · Oil Palm Production and Sustainability