Design and engineering economic evaluation of bacterial disinfection chamber for egg trays in cricket rearing

Abstract

This research aimed to study the design and engineering economic evaluation of bacterial disinfection chamber for egg trays in cricket rearing. The sterilization cabinet was operated using a combination of hot air and UVC light. It consisted of a heating chamber, a rotating shaft assembly for accommodating egg trays, a heating coil integrated with a fan system, a UVC light unit, and a temperature and time controller. The egg trays were subjected to bacterial disinfection at 3 different temperatures including 40, 50 and 60 °C with a constant heating duration of 5 minutes. From the experiments, it was found that when the temperature used for disinfection of egg trays increased, the capacity of the bacterial disinfection chamber tended to decrease, while the electric power consumption of the bacterial disinfection chamber tended to increase. The optimum temperature and time for disinfecting bacteria on egg trays is 60 °C at 5 min, the bacterial disinfection chamber could eliminate Escherichia coli and coliform bacteria contaminating the egg trays with the capacity of 100 trays/h and the electric power consumption of 0.45 kWh. The results of the engineering economic analysis revealed that an investment of 65,000 THB in the construction of a bacterial disinfection chamber for egg trays used in cricket rearing, which was operated 300 days per year at 8 hours per day, with a selling price of 1.5 THB per tray, resulted in a break-even point of 9,750 trays per year. The payback period was calculated to be 123 days, indicating a high economic feasibility for small- to medium-scale cricket farming operations. These findings suggest that the proposed disinfection chamber not only enhances hygienic conditions of reused egg trays but also offers a rapid return on investment, making it a viable option for sustainable insect farming practices.