Studies for the suitability of pine needles for using it as a substrate in biogas production

Abstract

The production of methane from biomass is necessary for waste management and energy independence. Cellulosic wastes, such as agricultural residues, grasses, straw, etc., can be added to animal wastes to facilitate their digestion because of their comparatively low carbon to nitrogen ratio. There is not enough information available on the conversion of substrates other than the conventionally utilized cattle dung for the creation of biogas. Pinus roxburghi, a plant belonging to the Pinaceae family, is becoming more and more popular as a crop for biofuel. About 3.43 lakh hectares make up Uttarakhand's pine forest. Amounts of organic carbon in pine needles are around 45.3%, 1.2% TKN, 11.4% hemicelluloses, 18.2% cellulose, and 9.1% lignin. Additionally, it contains 14% volatile content and 16% total solids, making it seem like a good feedstock for biomethanation.Therefore, study was done to determine whether pine needles in various shapes were suitable for producing biogas. According to the research, it is possible to produce biogas from ground pine needles treated with 4 g urea per kg of pine needles and combined with cattle dung in a 1:6 ratio.When digested at 35 °C, the total amount of biogas produced in 35 days was 20 liters. Initial and final pH variations during the substrate's biomethanation process were 7.63 to 7.59, TKN fluctuation between 1.26 and 1.39%, total alkalinity variation between 10.14 and 18.94 mg l-1, and C/N ratio variation between 33.71 and 20.64. Moreover, hemicelluloses dropped from 13.31 to 8.86% and cellulose content dropped from 18.51 to 13.54%. Thus, it is possible that pine needle biomethanation might be used to produce biogas.