Proper water treatment in closed heating and cooling systems is essential to prevent corrosion, ensure efficient operation, and avoid costly downtime. Historically, alkaline chromate inhibitors provided excellent corrosion protection but were phased out due to their toxicity and carcinogenic properties. Modern alternatives, particularly nitrite-based inhibitors combined with silicates, molybdates, and borates, effectively manage corrosion while mitigating environmental and health risks.
Understanding the Challenge: Nitrite Loss in Closed Systems
Nitrite-based inhibitors must maintain specific concentrations to remain effective. However, nitrite levels can decline without apparent leaks or losses of other treatment chemicals. This phenomenon typically occurs due to a biological process called denitrification, where certain bacteria convert nitrite to nitrogen gas or ammonia under anaerobic (oxygen-free) conditions.
Conditions Favoring Denitrification
Denitrification in closed systems generally occurs under these conditions:
- Presence of Nitrites and Organic Matter: Organic matter provides energy and promotes anaerobic conditions beneficial to bacteria.
- Anaerobic Environment: Absence of oxygen is crucial; the presence of oxygen significantly inhibits denitrification.
- Adequate Moisture: Bacteria thrive in sufficiently moist environments, making closed water systems ideal for their growth.
- Optimal pH Levels: Most denitrifying bacteria prefer near-neutral pH but can survive in a wide range (pH 2.0 to 10.0).
- Moderate Temperature: Denitrifying bacteria typically favor temperatures between 15-45°C.
How to Identify and Control Denitrification
Early identification and management are crucial for protecting your closed water systems. Here’s a recommended process:
- Nitrite and Nitrate Analysis: Regularly test system water for nitrite and nitrate levels to monitor inhibitor effectiveness.
- Microbiological Testing: Collect samples in sterile containers for microbiological analysis to detect bacterial presence.
- Microbicide Treatment: Implement periodic microbicide treatments based on recommended dosages. Consult your Watertech representative for specific application advice.
- System Circulation: Allow microbicide treatments to circulate thoroughly for optimal effectiveness, typically at least two hours.
- Post-Treatment Monitoring: Reassess nitrite levels 24 hours after treatment, adjusting inhibitor dosages as necessary based on results.
Partnering with Watertech for Reliable Solutions
Watertech of America, Inc. offers tailored solutions combining innovative technology and expert onsite support. By partnering with Watertech, your facility benefits from comprehensive programs that ensure:
- Enhanced corrosion control and extended system life.
- Reduced operational downtime and maintenance costs.
- Improved regulatory compliance and environmental responsibility.
Proactive monitoring and management through Watertech’s integrated approach will ensure your closed systems remain efficient, safe, and cost-effective.
Schedule Your Consultation
Contact Watertech today to request a comprehensive site survey. One of our Technical Engineers will work directly with you to assess your system and develop customized treatment solutions to meet your facility’s unique needs.
