Synergistic valorization of oil palm empty fruit bunch and pome sludge for balanced erosion control and runoff quality

The palm oil sector confronts significant sustainability challenges due to massive biomass waste generation, particularly Oil Palm Empty Fruit Bunches (OPEFB) and Palm Oil Mill Effluent (POME). This study aimed to valorize OPEFB-POME materials into biodegradable soil pellets in three distinct ratios to determine the optimum sludge ratio and evaluate their efficacy in mitigating soil erosion, surface runoff quality, and environmental sustainability. Rainfall simulation experiments were conducted on loamy sand, utilizing standardized soil characterization within erosion control plots at five application rates (T1, T2, T3, T4, and T5 g/ft 2 ) to evaluate the balance between physical protection and runoff quality. The results revealed that Pellet II (40:60 OPEFB-to-sludge ratio) exhibited the optimal dimensional stability, while application rate T2 provided the best balance between erosion control and runoff quality. Despite maximal pellet coverage (T5) decreasing turbidity by 97.80%, it exceeded the environmental thresholds for chemical oxygen demand (192 mg/L) and phosphorus (4.59 mg/L). Despite this rate reducing the nutrient load relative to higher application rates, it still introduced phosphorus levels exceeding eutrophication thresholds, marking it as a best-compromise solution rather than a completely benign intervention and providing the highest degree of balanced performance between physical protection and chemical runoff loading. This study highlights that OPEFB-POME pellets reflect an effective by-product valorization pathway, providing an integrated option for enhancing resource recovery in the palm oil sector by balancing soil conservation with aquatic environmental protection.