What are aseptic filling, dry sterilization, and wet sterilization?

In aseptic filling technology, dry and wet sterilization are two main methods for sterilizing packaging materials (such as bottles), and they differ significantly in principle, efficiency, cost, and environmental impact.

Dry Sterilization

Dry sterilization is an environmentally friendly technology that does not require rinsing with liquid disinfectants. Its core principle is the use of gaseous hydrogen peroxide (VHP) or other sterile gases to disinfect containers.

Principle: Hydrogen peroxide gas (sometimes activated to produce free radicals) is sprayed or blown onto the inner and outer surfaces of bottle preforms or empty bottles to kill microorganisms. After sterilization, the hydrogen peroxide decomposes into water and oxygen, eliminating the need for subsequent rinsing.

Advantages:

High efficiency and energy saving: Single bottle processing time is only 3-5 seconds, which is far more efficient than wet sterilization; no sterile water preparation is required, saving a large amount of water resources and steam energy consumption.

Environmentally friendly and safe: Zero water consumption, no chemical residue (residue amount can be less than 0.1 ppm), conforming to the low-carbon production trend, and avoiding the risk of by-products such as bromate.

Wide applicability: Particularly suitable for irregularly shaped bottles, high-end packaging, and aseptic cold filling production lines, such as the aseptic carbonated beverage lines of companies like Genki Forest and Wahaha.

Representative technologies: Dailong's PHP preform dry sterilization aseptic line, Krones' gaseous H₂O₂ isolation hood sterilization technology.

Disadvantages: 

Higher initial equipment investment (approximately 2-3 million RMB), but the cost can usually be recovered within 2-3 years through operating cost savings.

Safe and efficient, energy saving and emission reduction: Dailong's new generation preform chemical dry sterilization aseptic filling technology

Wet Sterilization

Wet sterilization is a traditional and widely used method for disinfecting packaging materials, relying on liquid chemical disinfectants.

Principle: Disinfectant solutions such as peracetic acid and hydrogen peroxide are used to spray or immerse empty bottles for disinfection, followed by rinsing with a large amount of sterile water to remove chemical residues. 1

Advantages:

Lower cost: Lower initial equipment investment (approximately 500,000-800,000 RMB), mature technology, and simple operation.

Applicability: Suitable for standard round bottles (such as ordinary mineral water bottles) and low-capacity needs of small water plants.

Disadvantages:

High energy consumption and high pollution: Water consumption can reach 4.2 tons per 10,000 bottles, high annual maintenance costs, and generates a large amount of wastewater and exhaust gas, which does not conform to the trend of green production.

Residual risk: If rinsing is not thorough, residual disinfectant (such as hydrogen peroxide) may affect product safety; the national standard limit is 0.5 ppm.

Current application status: Still the mainstream in the industry, but is gradually being replaced by dry sterilization technology, especially in areas with high environmental pressure.

Summary Comparison

In summary, dry sterilization represents the trend of aseptic filling technology towards high efficiency, energy saving, and environmental protection, especially suitable for medium and large enterprises and brands pursuing sustainable development; while wet sterilization still occupies a place in some scenarios due to its low cost threshold.