ProChemTech Cooling Tower Biocides
Cooling Tower Biocides for Eliminating Harmful Bacterial Growth & Contamination
Cooling tower operators constantly battle harmful bacterial growth, biofilm buildup, and microbial contamination that can compromise system efficiency and pose serious health risks. Addressing these complex biological threats internally without specialized expertise from professional water treatment companies can be extremely challenging.
ProChemTech provides specialized cooling tower biocides and water-treatment chemistry to eliminate harmful bacteria in cooling tower systems. We are ISO 9001:2000 registered for water management programs and maintain two EPA-registered biocide production facilities to deliver customized treatment solutions.
Read on to learn more about the different types of cooling tower biocide control that are best for your system.
Biological Control for Cooling Towers
Cooling towers remove heat through contact between warm recirculating water and outside air. That process can introduce bacteria, algae, fungi, and other microorganisms into the system. Microbial growth can reduce heat transfer, clog water passages, increase the risk of corrosion, and pose health risks. Cooling tower biocides control that growth before it interferes with system performance.
Most biocides for cooling towers fall into two categories: oxidizing and non-oxidizing. Oxidizing biocides react quickly and are often used in systems with short retention times or high water volume. Non-oxidizing biocides employ distinct chemical mechanisms and are often selected when water quality, discharge limits, metallurgy, pH, or chemical compatibility influence product choice.
Biocides fall into two categories: oxidizing and non-oxidizing:
Oxidizing Cooling Tower Biocides
Oxidizing cooling tower biocides kill microorganisms by damaging cell walls, proteins, and other cell structures. These products usually rely on chlorine, bromine, chlorine dioxide, hydrogen peroxide, ozone, or another oxidizing chemistry.
Oxidizers react quickly, so they are often used in systems with short retention times. They are also common in high-volume systems because they can provide broad microbial control at practical feed rates. These products require feed control and routine monitoring because their activity changes with pH, organic load, and water chemistry.
This biocide class includes the following:
Bromine: Bromine-based biocides maintain activity over a wider pH range than chlorine-based biocides. Bromine is useful in high-pH cooling tower programs because it maintains activity better than chlorine as pH rises. It can be supplied as stabilized bromine or generated on site as electrolytic bromine.
Electrolytic Bromine: Electrolytic bromine is generated at the point of use from a sodium bromide and sodium chloride solution. ProChemTech’s proprietary ElectroBrom and MiniBrom systems produce bromine on demand, which reduces the need to store and handle conventional biocide products.
Chlorine: A common oxidizing biocide for cooling tower applications. It is cost-effective, but its activity drops at higher pH levels. Chlorinated byproducts can also form, so chlorine programs require proper feed control and monitoring.
Chlorine Dioxide: This treatment provides microbial control without forming trihalomethanes or other chlorinated byproducts. It remains stable across a range of pH levels and penetrates biofilms. Those properties make it useful for systems with established contamination.
Hydrogen Peroxide: This compound decomposes into water and oxygen after treatment. It works against a broad spectrum of microorganisms. Some cooling tower programs require stabilizers or specific feed conditions to maintain effective treatment levels.
Ozone: This on-site oxidizer leaves no lasting chemical residual in the system. Ozone programs require generation equipment, contact time, and proper control.
Non-Oxidizing Cooling Tower Biocides
This class of cooling tower biocides includes many chemical formulations designed for specific water treatment conditions. Product selection depends on water quality, biological growth, pH, discharge limits, metallurgy, and chemical safety requirements.
Non-oxidizers act by disrupting cell membranes or interfering with cellular functions. They are often used in systems where oxidizing biocides may increase the risk of corrosion or interfere with other treatment chemicals.
This biocide class includes the following:
DBNPA: Dibromonitrilopropionamide (DBNPA) is a fast-acting, broad-spectrum biocide that rapidly breaks down in the environment. It works effectively against bacteria, fungi, and algae while being less corrosive than many oxidizing alternatives.
Isothiazolinone: Provides excellent control against sulfate-reducing bacteria and other problematic microorganisms in cooling systems. These compounds exhibit good stability across a range of pH values and can be effective at relatively low concentrations. They provide good residual activity for systems with high residence time.
Glutaraldehyde: Works by cross-linking proteins and nucleic acids in microbial cells, providing effective broad-spectrum antimicrobial activity. It remains stable across a wide pH range and is particularly effective against biofilm-forming bacteria and anaerobic organisms.
Quaternary Ammonium: These surface-active compounds disrupt cell membranes and can provide residual microbial control. Compatibility with other treatment chemicals should be checked.
View this table to compare the benefits and properties of each biocide:
| Biocide Type | Class | pH Range | Typical Use | Treatment Notes | Residual Activity |
| Bromine | Oxidizing | Wide (6-9) | High-pH cooling tower systems | Often used where chlorine loses activity at higher pH | Good |
| Electrolytic Bromine | Oxidizing | Wide (6-9) | On-site bromine generation | Produces bromine on demand from a sodium bromide and sodium chloride solution | Short |
| Chlorine | Oxidizing | Limited (6-7.5) | Cost-sensitive systems with controlled pH | Activity drops as pH rises, and chlorinated byproducts can form | Poor |
| Chlorine Dioxide | Oxidizing | Wide (6-10) | Biofilm and established microbial deposits | Does not form trihalomethanes or other chlorinated byproducts | Fair |
| Hydrogen Peroxide | Oxidizing | Wide (6-9) | Broad-spectrum oxidizing treatment | Breaks down into water and oxygen after treatment | Poor |
| Ozone | Oxidizing | Wide (6-9) | On-site oxidizing treatment | Requires generation equipment and does not provide a lasting residual | None |
| DBNPA | Non-oxidizing | Wide (6-9) | Fast microbial control | Breaks down quickly after use | Fair |
| Isothiazolinone | Non-oxidizing | Wide (5-9) | Longer residence time systems | Can remain active at relatively low concentrations | Good |
| Glutaraldehyde | Non-oxidizing | Wide (6-9) | Biofilm-forming bacteria and anaerobic organisms | Cross-links proteins and nucleic acids in microbial cells | Excellent |
| Quaternary Ammonium | Non-oxidizing | Limited (6-8) | Compatible systems that need residual microbial control | Compatibility with other treatment chemicals should be checked | Excellent |
Proprietary Cooling Tower Biocide Solutions from ProChemTech
ProChemTech offers cooling tower biocides and related water treatment chemistry through a catalog of more than 200 specialized products. These capabilities include biocides, bio dispersants, stabilized bromine, feed systems, monitoring controls, and on-site service support.
Our proprietary cooling water treatment programs can operate at higher cycles of concentration, reducing water and chemical use. We also provide on-site cooling water treatment services, wherein our technicians monitor system conditions, adjust chemical levels, and ensure proper dosing.
The approach we take combines product expertise with complete system support. We design integrated cooling tower systems that incorporate proper biocide feed systems and monitoring equipment tailored to your facility’s needs. Each partnership includes a comprehensive 5-year warranty against corrosion damage.
Aqua Ionic Eliminates Legionella and Scale
Aqua Ionic is ProChemTech’s patented water management technology that uses softened makeup water for cooling towers. This technology operates at 8 to 10 cycles of concentration compared to conventional systems at 2 to 4 cycles. Water savings can exceed a 70% decrease in blowdown while eliminating scale formation.
Routine testing in seventeen cooling systems showed “none detected” results for Legionella bacteria. This result is confirmed by literature showing that Legionella do not reproduce in high pH, alkalinity, and dissolved solids waters found in Aqua Ionic cooling towers.
Aqua Ionic systems operate at a high pH and require compatible chemical treatment. Standard chlorine loses its biocidal effectiveness at these elevated levels and cannot properly treat the water. Facilities must instead use bromine as their cooling tower biocide and can apply it as a stabilized liquid or generate it on-site as electrolytic bromine.
Common Contaminants That Cooling Tower Biocides Treat
Cooling towers can have numerous contamination challenges that require targeted biocide treatment to maintain safe and efficient operation. The most common contaminants that biocides and biodispersants are designed to address include:
Legionella: Legionella bacteria thrive in warm water environments and can cause severe respiratory illness known as Legionnaires’ disease.
Airborne Contaminants: Dust, pollen, debris, and other particles enter cooling towers through air intake systems during normal operation. These contaminants provide nutrients for microbial growth and can create deposits that interfere with heat transfer efficiency.
Biofilms: Biofilms are protective layers of bacteria and other microorganisms that adhere to surfaces within cooling systems. These slimy matrices protect bacteria from standard cleaning methods and create ideal conditions for continued microbial growth.
Scaling: Mineral deposits form when dissolved minerals in water precipitate onto heat exchanger surfaces and piping. While scaling is primarily a chemical issue, biological activity can accelerate scale formation and make deposits more difficult to remove.
Biological growth: Algae, bacteria, fungi, and other microorganisms flourish in the warm, nutrient-rich environment of cooling towers. Unchecked biological growth can clog distribution systems, reduce heat transfer efficiency, and create foul odors.
Microbiologically Induced Corrosion (MIC): Certain bacteria produce acids and other corrosive byproducts that accelerate metal degradation in cooling systems. MIC can cause rapid pitting and failure of pipes, heat exchangers, and other critical components.
Partner with ProChemTech for Effective Cooling Tower Biocide Solutions
Biological control for cooling towers is essential for preventing dangerous microbial contamination and maintaining system efficiency. Proper biocide selection and application protect facilities from serious health risks and costly equipment damage.
At ProChemTech, we combine decades of experience with EPA-registered biocide manufacturing capabilities to deliver comprehensive cooling tower treatment solutions. Our team of water treatment specialists works closely with facilities to develop customized biocide programs that address specific contamination challenges. Click below for a quote and to learn more about how ProChemTech can protect your cooling tower systems with effective biological control solutions.