Algae in cooling water systems is often considered a minor nuisance that is easy to overcome. However, in reality, uncontrolled algae growth can be one of the main causes of decreased efficiency in industrial cooling systems.

Algae grow rapidly in a supportive environment: warm temperatures, sufficient light, and the availability of nutrients such as phosphate and nitrate. This combination is often found in cooling tower systems that do not have adequate biological protection.

Without realizing it, the algae biofilm that forms can block water flow, reduce heat transfer, and accelerate corrosion and fouling on pipes and equipment. The impact? Increased energy consumption, more frequent maintenance, and equipment damage that requires expensive replacement.

Risks That Occur If Left Untreated

If not handled systematically, algae problems not only reduce efficiency but also threaten the sustainability of industrial operations.

Some real risks that often arise due to algae contamination include:

1. Decreased heat exchanger efficiency

The algae layer that sticks to the surface of the heat exchanger acts as an insulator, inhibiting the heat transfer process. This causes the system to work harder, consuming more energy.

2. Increased operational costs and downtime

Manual cleaning of algae-infested systems takes time and effort, sometimes requiring a shutdown for a thorough cleaning process.

3. Increased risk of microbiological corrosion (MIC)

Algae and other microorganisms form biofilms that create an anaerobic environment at some points in the system, triggering pitting corrosion that is difficult to detect until it is severe.

4. Potential violation of environmental standards

Effluent from cooling systems contaminated with excessive algae can exceed water quality thresholds set by environmental regulations, risking sanctions.

With such complex risks, it is clear that algae prevention cannot be taken lightly. It requires an integrated approach that is not only reactive but also proactive.

Cooling Tower Algae Prevention Solutions

Preventing algae growth in cooling tower systems requires a holistic approach, combining physical, chemical, and operational measures. Algae can grow rapidly when conditions are favorable — warm water, the presence of nutrients such as phosphate and nitrate, and exposure to sunlight. Here are the main steps in preventing their growth:

1. Nutrient Control

Algae require nutrients such as phosphate and nitrogen to thrive. One of the most effective ways to prevent their growth is to control the concentration of nutrients in the water. This can be done by:

Ensuring the make-up water source is free from high-nutrient contaminants.
Maintaining a consistent blowdown program to reduce nutrient accumulation.

2. Biocide Application

Biocides are chemicals designed to inhibit or kill microorganisms, including algae. There are two main types:

Oxidizing biocides (e.g., chlorine, bromine): kill algae quickly and are very effective, but must be monitored to prevent damage to system materials.
Non-oxidizing biocides (e.g., isothiazolin, glutaraldehyde): work more slowly but are effective for long-term prevention and control of biofilms.

The use of biocides must be done in rotation or alternately to prevent microbial resistance.

3. Control pH and Water Chemistry

Maintaining water pH in the optimal range (usually between 6.5–8.5) can inhibit algae growth. In addition, controlling other chemical parameters such as alkalinity, hardness, and total dissolved solids (TDS) is important to prevent the creation of an environment that supports biological growth.

4. Reducing Sunlight Exposure

Because algae require light for photosynthesis, limiting direct sunlight exposure to the cooling tower is an effective preventive measure. This can be done by:

Use a cover or light shield on the open part of the cooling tower.
Redesigning the open area to reduce the intensity of incoming light.

5. Periodic Filtration and Blowdown System

Filtration helps filter out solid particles and microorganisms before they enter the main system.

Blowdown is the process of removing some of the circulating water containing dissolved solids and contaminants. Performed periodically, blowdown helps maintain low concentrations of substances that support algae growth.

6. Physical Cleaning and Periodic Maintenance

Performing regular cleaning of the cooling tower, especially on the water surface area and tower walls, can inhibit the formation of biofilms and algae colonies. Periodic maintenance includes:

Scrubbing or brushing the surface.
Draining and refilling the system at certain times.
Periodic inspections are conducted to detect early signs of microorganism growth.

7. Physical Disinfection

Non-chemical disinfection such as:

UV light: Damages algae DNA and prevents replication.
Ozonation: Oxidizes microorganisms in water, effectively without leaving residues.

This technology can be used as a complement to chemical programs for comprehensive protection against microorganisms.

8. Real-Time System Parameter Monitoring

The application of sensors and automatic controls allows the system to detect fluctuations in water quality, such as pH, temperature, biocide concentration, and turbidity levels. Real-time monitoring provides accurate information needed to make quick decisions, including when to add biocide or perform blowdown.

9. Operator Training and Clear SOPs

The human factor also plays an important role. Operators must understand the SOPs for algae control, chemical use, and the importance of preventive measures. Regular training and documented procedures help maintain consistency and quality of cooling tower system operation.

Prevention is Better than a Cure

Algae growth in cooling water systems is not a small problem that can be ignored. Its impact on energy efficiency, system reliability, and operational costs is significant. Therefore, a comprehensive and sustainable prevention approach is needed.

With the support of technology, the right chemical treatment, and an experienced team of experts, Lautan Air Indonesia is ready to be your trusted partner in keeping your cooling system clean, efficient, and free from algae.

With more than 40 years of experience in industrial water treatment, Lautan Air Indonesia understands that each cooling system has its own characteristics and challenges. We not only sell products, but also offer integrated solutions, from system design, chemical selection, equipment installation, to monitoring and after-sales support.

Don’t wait until your cooling system stops due to an algae attack. Contact the Lautan Air Indonesia team today for a consultation and find the right solution for your cooling water systems needs.

How to Prevent Algae in Cooling Water Systems