Development and Evaluation of a Mini Trommel for Small-Scale Vermicompost Screening

Abstract

The increasing demand for high-quality compost has highlighted the need to improve post-composting processes, particularly sifting, which remains labor-intensive and time-consuming in many small- and medium-scale operations. This study aimed to develop a mini compost trommel machine using locally available materials and technologies to enhance screening efficiency, reduce manual labor, and promote sustainable compost production. The machine was designed, fabricated, and evaluated based on input capacity, screening efficiency, electrical energy consumption, noise level, and economic viability. Testing was conducted using 150 kg of vermicompost across five trommel screen speeds (10, 20, 30, 40, and 50 rpm) with three replications per treatment, following a Completely Randomized Design. Results showed a maximum screening efficiency of 97.65% at 10 rpm and an input capacity of 441.21 kg/hr at 30 rpm. Noise levels remained within safe occupational limits (66 –75 dB), and no significant variation in energy consumption was observed across treatments. Economic analysis indicated a favorable payback period of 1.04 years and a 51.35% rate of return. The findings demonstrate that the mini compost trommel machine is a cost-effective, energy-efficient, and high-performance solution suited for small-scale compost producers.