Design and construction of semi-continuous sterilization machine for growing media using ultraviolet light

• Main Authors: Unadi, A., Parikesit, A., Nurhasanah, A., Tjahjohutomo, R., Budiharti, U., Samudiantono, A.
• Format: Conference Proceeding
• Language: English
• Subjects: Composting; Lamps; Microorganisms; Nutrients; Performance tests; Semicontinuous design; Soil mixtures; Soils; Sterilization; Ultraviolet radiation
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/5.0190975

Growing media is material for nursery. It is composed from soil and organic compost which meet growing requirements for seeds, including crumb, good water-holding capacity, non-toxic, contain nutrients required for plant growth and contain allowable amount of harmful microbes. In general, growing media are composed from a mixture of soil and compost with the ratio of 1:1. Sterilization of growing media is required to inhibit the growth of harmful micro-organisms. Killing pathogenic microorganisms using Ultraviolet (UV) light have been used in many areas of health, food and beverage preservation because of it highly effective for eliminating harmful microorganism, requires low energy, takes less time, and requires smaller space for sterilization process. A batch model of UV sterilization of 2 kg loading capacity using 2 unit of 20-Watt UV germicidal lamps of 254 nm wave length has been evaluated for sterilization growing media. The number of Aerobic microbes decreases from 1.245 ×109 CFU/g to 6.50 ×107 CFU/g and 7.70×106 CFU/g for the duration of UV sterilization of 30 and 60 min respectively. A semi-continuous UV sterilization machine using 32 unit of UV germicidal lamps, 20 watt each has been designed, fabricated and tested. The dimension of the machine was 2,950 mm length 650 mm width and 1,900 mm height and load capacity were 259.2 kg/hour. The performance test result of the machine with the duration of sterilization for 5 min showed that the total number of bacteria was decreased from 1.52×107 CFU, to 7.50×106 CFU/g.