Design, Fabrication, and Performance Evaluation of a Small-Scale Compost-Turning Machine

Abstract

A small-scale compost turning machine was designed, fabricated, and evaluated to speed up the decomposition rate of compost piles by giving optimum aeration through frequent turning, resulting in faster compost production. The designed compost turning machine mainly consists of thrower blades, a power transmission system, and prime mover, a side cover, a scraper, wheels, and a frame. The machine's design was created in AutoCAD software and fabricated in the metalwork shop. The performance evaluation of the machine at three different peripheral speeds [1090 rev∙min^-1, 1276 rev∙min^-1, and 1386 rev∙min^-1] of the thrower blade was carried out in terms of turning capacity, turning efficiency, pulverizing efficiency, and fuel consumption. The compost turning machine operated at 1276 rev∙min^-1 optimally, and has a turning capacity of 77.35 kg∙min^-1, a turning efficiency of 99.79%, a pulverizing efficiency of 97.21%, and fuel consumption of 2.16 L∙hr^-1. Simple cost analysis revealed that at a custom rate of 0.17 Php∙kg^-1 of compost turned, the payback period of the investment is 172 days of turning operation. The break-even point is 33,923 kg∙ yr^-1 with revenue of 75,741.12 Php∙yr^-1 compared to manual operation with a recorded capacity of 46.67 kg∙min^-1 having only revenue of Php 44,315.17 Php∙year^-1.