Development and Performance Evaluation of Double Shaft Plastic Bottle Crusher for Small Scale Industrial Application

Abstract

Plastic pollution is a problem that is affecting many aspects of human endeavour. Searches are being made for ecofriendly alternatives and waste management practices that can lessen the impact of plastic pollution. On the list are waste plastic reuse, use of bioplastics, reduction of reliance on plastic usage, and plastic waste recycling. In this technical brief, a Plastic shredder was developed to recycle plastic waste in the value chain. Plastic shredder is a machine that turns used plastic bottles to smaller particle sizes to enhance portability, easiness and readiness for use into new products. While in operation, the prime mover drives the transmission shafts with low speed in the range of 25 to 65 rpm to give shredding torque that masticates materials fed in, into desired granular size. Bivariate Linear regression was the statistical model used to understand the relationship between the two variables of evaluation, the predictor x (speed) and the response variable y (shredding capacity). Since significance F (0.0216) is less than 0.05, there is 95% confidence that there is linear relationship between speed of rotation and shredding capacity of the machine. Model equation is therefore given as Y= 0.952 X1 – 11.725 ± 2.53. The machine respectively gave highest shredding capacity for PET bottles, Tin can and wastepaper as 56.52 kg h-1, 29.60 kg h-1 and 42.09 kg h-1 at optimum speed of 65 rpm. If operated for 8 hours in a day, it can favorably shred almost half a ton of plastic bottles (452.16 kg day-1). The machine was developed at an affordable cost of $817.72. The paper shredded with the machine can be pulped and made into poultry egg crates and paper print used in building industry. The machine is less stressful to operate and economical to run and maintain. If the machine is widely adopted, the menace caused by nonbiodegradable materials like plastic will be ended.