Application of Hypochlorous Acid Water in Smart Agriculture and Aquaculture

Hypochlorous acid water (HOCl) is a weakly acidic disinfectant with strong oxidizing properties. It is produced by adding chlorine to water in one of the following forms: elemental chlorine (chlorine gas), sodium hypochlorite solution, or calcium hypochlorite powder. Its characteristics are as follows:

Characteristics

1. Broad-Spectrum Disinfection: Hypochlorous acid water effectively kills bacteria, viruses, fungi, and other microorganisms. Due to its strong oxidizing properties, it destroys microbial cell walls and viral envelopes, making it difficult for microorganisms to develop resistance.
2. High Safety Profile: Hypochlorous acid water is relatively safe for humans and the environment. After use, it decomposes into water. It should be noted that minimal amounts of trihalomethanes may be generated during its application, but the concentrations are typically low, comparable to those found in tap water.
3. Low Stability: Hypochlorous acid water is sensitive to environmental factors such as light and temperature, which can cause rapid degradation. As a result, it has a short shelf life, and it is recommended to produce and use it immediately to ensure optimal disinfection efficacy.

Applications

Hypochlorous acid water has been widely used in various fields, including healthcare, food processing, and environmental disinfection. In the context of smart agriculture and aquaculture, it also demonstrates significant application potential.

Applications of Hypochlorous Acid Water in Smart Agriculture 

(1) Cultivation Applications

Hypochlorous acid water is effective in seed disinfection, soil improvement, and plant growth regulation. Examples include:

• Seed Disinfection: Soaking seeds in hypochlorous acid water effectively removes pathogens on the seed surface, improving germination rates.
• Soil Improvement: It suppresses harmful microorganisms in the soil, enhancing the microbial environment and promoting healthy plant growth.
• Plant Growth Regulation: At appropriate concentrations, hypochlorous acid water stimulates plant growth and increases yields.

(2) Pest and Disease Control

Hypochlorous acid water serves as an eco-friendly alternative to traditional chemical pesticides for pest and disease management. Examples include:

• Crop Surface Spraying: Spraying hypochlorous acid water on crops eliminates pathogens, preventing and controlling diseases.
• Irrigation Systems: Adding hypochlorous acid water to irrigation systems inhibits soil pathogens, reducing disease occurrence.

(3) Post-Harvest Processing

Hypochlorous acid water can also be used in post-harvest treatment to extend shelf life and reduce losses. For instance: 

• Cleaning Fruits: Washing fruits with hypochlorous acid water removes surface bacteria. When followed by cold storage, it extends freshness and maintains product quality.

3. Applications of Hypochlorous Acid Water in Aquaculture 

(1) Aquaculture Applications

Hypochlorous acid water is used to improve farming environments and prevent fish diseases. In smart aquaculture, sensors monitoring parameters such as water temperature and dissolved oxygen levels are commonly used. However, underwater sensors are prone to damage from algal growth and require regular cleaning or protective casing to maintain functionality. Hypochlorous acid water can be applied in the following ways:

• Water Purification: Hypochlorous acid water effectively eliminates pathogens in the water, reducing bacterial counts and improving water quality. It oxidizes organic matter in the water, reduces COD levels, and converts ammonia nitrogen into nitrogen gas, lowering ammonia nitrogen concentrations.
• Fish Disease Prevention and Control: By preventing and controlling fish diseases, hypochlorous acid water reduces the need for antibiotics, helping to address the growing issue of antibiotic resistance. This aligns with the sustainable aquaculture trend.

(2) Best Aquaculture Practices (BAP) Certification

The Best Aquaculture Practices (BAP) certification, established by the Global Aquaculture Alliance (GAA), is a third-party verification system that ensures aquaculture meets the highest standards in environmental protection, food safety, social responsibility, animal welfare, and traceability. The application of hypochlorous acid water in aquaculture helps farmers meet BAP certification requirements, enhancing their products' international competitiveness.

4. Research Findings and Case Studies

Research Findings

1. Post-Harvest Disease Control for Guava (Taichung District Agricultural Research and Extension Station): Research shows that soaking guava fruits in 40 ppm hypochlorous acid water reduces storage-related disease incidence by 50%. This effectively addresses quality issues caused by diseases during storage and transportation.
2. Collaboration Between MingDao University and YiHung Environmental Technology Co.: Studies explored the use of hypochlorous acid water in organic agriculture for disease control, orchid cultivation, and tissue culture of hydroponic vegetables.
3. Green Bean Sprout Growth Study (O’Clean): Experiments with varying concentrations of hypochlorous acid water demonstrated its ability to promote green bean sprout growth without residual chlorine.

Regulatory and Practical Applications

1. Food-Grade Chlorine Disinfectants in Slaughterhouses (Bureau of Animal and Plant Health Inspection and Quarantine, Council of Agriculture): Guidelines were established for the use of food-grade chlorine disinfectants, including hypochlorous acid water, in slaughterhouses. The regulations cover concentration limits and usage methods to ensure meat hygiene and safety.
2. Promotion of Smart Aquaculture (Fisheries Agency): Subsidies were provided for the installation of machines producing electrolyzed seawater, hypochlorous acid water, and chlorine dioxide as strong oxidizing agents. These technologies are being promoted to support smart aquaculture practices.

5. Advantages and Disadvantages of Hypochlorous Acid Water in Agriculture and Aquaculture

Hypochlorous acid water has various advantages in smart agriculture and aquaculture applications but also presents certain drawbacks.

6. Future Development Trends and Challenges

Hypochlorous acid water has promising applications in smart agriculture and aquaculture. Future development trends include:

Development Trends 

1. Integration with AI Technology: Combining the use of hypochlorous acid water with AI technology, such as employing AI systems to analyze data, accurately control the concentration and dosage, improve pest and disease control effectiveness, and develop predictive models to prevent outbreaks.
2. Development of Advanced Hypochlorous Acid Water Generators: Creating more stable and efficient generators to extend the shelf life of hypochlorous acid water and reduce costs.
3. Expansion of Application Areas: Expanding its use to more agricultural and aquaculture fields, such as livestock farming and fisheries.

Challenges

1. Technical Research: Further research is needed to understand the effects of hypochlorous acid water on various crops and aquaculture organisms, as well as to establish optimal usage methods and concentrations.
2. Industry Promotion: Increased efforts are needed to train and educate farmers and aquaculturists, raising awareness and improving the adoption of hypochlorous acid water in their practices.
3. Regulatory Framework: Developing regulations to standardize the use of hypochlorous acid water in agriculture and aquaculture to ensure food safety and environmental protection.

7. Conclusion

As a safe and eco-friendly disinfectant, hypochlorous acid water offers broad application prospects in smart agriculture and aquaculture. In the face of climate change challenges and growing food safety demands, hypochlorous acid water is poised to become a critical tool for promoting sustainable agricultural development.

Through ongoing technological advancements and industry promotion, hypochlorous acid water can enhance production efficiency and quality in agriculture and aquaculture, paving the way for a safer and more sustainable agricultural production model.