Article | Efficient and Sustainable : Closed Loop Water Treatment Systems Conserve Water, Reduce Waste, and Enhance Operational Performance

Closed loop water treatment systems are designed to maintain water quality and protect the components of the system from corrosion, scaling, and fouling. These systems are typically used in HVAC (heating, ventilation, and air conditioning), industrial cooling, and heating applications. The goal is to ensure efficient operation and extend the lifespan of the equipment.

Here’s a detailed look at each component of closed loop water treatment:

1. Cleaning

Remove contaminants that can cause corrosion, scaling, or biological growth.

• Mechanical Cleaning: Physical removal of large debris using brushes or other tools.
• Chemical Cleaning: Application of cleaning agents to dissolve scale, rust, and biofilm. Common chemicals include:
  • Acids (e.g., hydrochloric, sulfamic): Used to dissolve mineral scales.
  • Alkaline cleaners: Used to remove organic deposits and grease.
  • Biocides: Used to eliminate biological growth such as algae and bacteria.
• Flushing: High-flow water flushing to carry away loosened debris and contaminants.

2. Passivation

Form a protective oxide layer on metal surfaces to prevent corrosion after cleaning.

• Chemical Passivation: Introduction of chemicals that react with the metal surfaces to form a stable, protective layer. Common chemicals include:
  • Sodium nitrite: Forms a protective oxide layer on steel surfaces.
  • Molybdate: Provides corrosion protection by forming a passivation layer.
• Process: Typically involves circulating the passivation solution through the system for a specified period, followed by thorough rinsing.

3. Filtration

Continuously remove suspended particles and impurities to maintain water quality.

• Types of Filters:
  • Mechanical Filters: Use physical barriers such as screens or cartridges to trap particles.
  • Sand Filters: Use sand media to filter out particles.
  • Cartridge Filters: Use replaceable cartridges to capture contaminants.
  • Magnetic Filters: Use magnetic fields to capture iron and steel particles.
  • Side-Stream Filtration: A portion of the water is continuously filtered to remove impurities without disrupting the main flow.

4. Inhibitor Replacement

Add chemicals to the water to prevent corrosion and scaling.

• Corrosion Inhibitors: Protect metal surfaces by forming a protective film. Common types include:
  • Phosphates: Effective for controlling both corrosion and scale.
  • Silicates: Provide a protective layer on metal surfaces.
  • Zinc Compounds: Used in combination with phosphates for enhanced protection.
• Scale Inhibitors: Prevent the formation of mineral scales. Common types include:
  • Polyphosphates: Inhibit scale formation by binding with calcium and magnesium ions.
  • Phosphonates: Provide long-lasting scale inhibition.
• Biocides: Control biological growth such as algae, bacteria, and fungi. Types include:
  • Oxidizing Biocides: Such as chlorine and bromine.
  • Non-Oxidizing Biocides: Such as glutaraldehyde and isothiazolinones.

Maintenance and Monitoring

• Regular Testing: Periodic testing of water quality parameters such as pH, conductivity, inhibitor levels, and microbial counts.
• Inspection: Routine inspection of system components to detect and address issues early.
• Chemical Adjustments: Regular adjustment of chemical dosages based on water quality test results to maintain optimal protection.

Benefits of Closed Loop Water Treatment :

• Enhanced System Efficiency: Clean and well-maintained systems operate more efficiently, reducing energy consumption.
• Extended Equipment Lifespan: Proper treatment prevents corrosion and scaling, extending the life of system components.
• Reduced Maintenance Costs: Preventive treatment reduces the need for frequent repairs and replacements.
• Improved Reliability: Consistent water quality ensures reliable operation and reduces the risk of system failures.

Effective closed loop water treatment requires a comprehensive approach, including proper design, regular monitoring, and timely maintenance. Each component plays a crucial role in ensuring the long-term performance and reliability of the system.

NCH Asia Pacific in dedicated to helping commercial businesses create safe, efficient working environments and working with you to promote a healthy water environment for any commercial property. Contact us today to find out more about how we can support your business.