Development and Performance Analysis of a Mini Twin-Shaft Shredder for Efficient Polyethylene Terephthalate (PET) Bottle Recycling

Polyethylene terephthalate (PET) stands out as the most widely recycled plastic globally. However, in Philippines, processes associated with PET recycling, particularly transportation of bottles from collectors and consolidators to processing plants, demand significant time, monetary resources, effort due lack appropriately sized shredder machines local junkshops reduce bulkiness. As a response, this study aimed design mini twin-shaft bottle shredder. The took into account constraints prerequisites junkshop proprietors, municipal barangay government units, non-government organizations.
 machine was comprised five essential components: hopper, shredding chamber, power transmission, prime mover, frame. Post-consumer were employed test materials for experimentation at different treatment speeds: 30, 40, 50rpm. experimental layout followed completely randomized (CRD). Performance metrics, including capacity, efficiency, energy demand, scrutinized based on shaft speed alterations through analysis variance testing. Additionally, comparison among means executed using least difference (LSD) method, significance level 5%.
 Results indicated that highest input capacity 34.07 kg/hr attained 50rpm, along efficiency 91.3%. presence unshredded identified primary cause device inefficiency, constituting 6.44% total input. calculated 0.132 kW-hr/kg. resulting product dimensions primarily ranged between 25-50mm. A cost demonstrated would need shred cumulative 6,889kg reach breakeven point, given custom rate Php7/kg ($0.12/kg). initial investment Php124,383 ($2,194.71) could be recuperated mere 1.91 years, yielding an added net income Php210,000/yr ($3,705.40/yr) and/or consolidators.