Design, Validation, and Examination of the Performance Improvement of Dewatering System Implemented for Biogas Slurry

Abstract

The project addresses the pressing need for organic fertilizers in Nepal and explores an eco-friendly alternative to chemical fertilizers. By dewatering biogas residue, this research contributes to sustainable agriculture practices. The project's methodology involved a combination of research, literature recommendations, and guidance from experienced supervisors. SolidWorks was utilized for the design phase, while ANSYS facilitated simulation works. Subsequently, the testing of the dewatering machine was conducted. The biogas slurry used for testing and sun-drying was sourced from a prototype 1m3 capacity biogas plant. The machine's performance was evaluated at various operating speeds, with 8 rpm identified as the most efficient. Notable outcomes included a liquid yield of 52.51%, an extraction efficiency of 79.11%, and extraction losses amounting to 22.80%. To enhance the quality of the organic fertilizer, the slurry sample underwent sun-drying for different durations: 24, 48, and 72 hours. Nutrient concentrations (TS, N, P, K) were analyzed, that came with the 48-hour sun-drying period proving to be the most effective in reducing Total Solid contents. Comparatively, pre-treating the slurry sample for 24 and 48 hours prior to testing in the dewatering machine allowed for an assessment of the machine's efficiency, offering valuable insights to be contrasted with the sun-drying process. This research paves the way for a greener, more efficient method of dewatering biogas slurry, aligning with Nepal's agricultural and environmental sustainability goals.