Biogas Production from Co-Digestion of Landfill Leachate and Pineapple Peel

Abstract

This research study examined the behaviour of co-digestion of landfill leachate with pineapple peel, focusing on biogas production. Laboratory scale batch experiments were conducted to investigate mono-digestion of leachate and of pineapple peel, and their co-digestion with three different mixing ratios. The inoculum and pineapple peel were derived from the Golden Circle factory and the leachate was collected from the Rochedale Landfill site in Brisbane, Australia. Mono-digestion of leachate had methane yield of 24 L kgVSconsumed-1 and volatile solids (VS) removal efficiency of 37%. The results from mono-digestion of pineapple peel showed the higher methane yield of 317 L kgVSconsumed-1 and higher VS removal efficiency of 80%. The reasons for better performance of digestion in pineapple peel digestion are the pineapple peel had a carbon to nitrogen ratio (C/N) of 24 to 1 that is suitable for anaerobic digestion process and the leachate sample was in mature age, as evidenced from low volatile solids (VS) and chemical oxygen demand (COD) composition and high pH level. Co-digestion batch experiments were run in the same reactors. 25 L of leachate was mixed with three ratios of pineapple peel - one, two and three kgVSpineapple peel m-3. The results showed that co-digestion of the leachate with two kgVSpineapple peel m-3 achieved the highest methane yield of 269 L kgVSconsumed-1 and 80% VS and 89% COD removal efficiency with good stability in the reactor. Further addition of pineapple peel at three kgVSpineapple peel m-3 to the leachate slightly decreased the biogas yield and overall VS and COD removal efficiency. The co-digestion results showed better performance than the mono-digestion of leachate due to synergism from pineapple peel as a co-substrate.