How to Choose Antimicrobial and Algaecide Agents for Recirculating Water Systems

In the circulating water system, especially in the cooling water tower pool, due to the suitable temperature and the nutrient provided by the sticky mineral substances in the water, microorganisms reproduce rapidly. Microorganisms can make the water acidic and dirty, and the biofilm produced can accelerate the accumulation of scale and equipment corrosion, while severely reducing the heat transfer efficiency of the cooler.

Common bactericidal and algicidal agents used in circulating water systems are generally divided into oxidative bactericidal and algicidal agents and non-oxidative bactericidal and algicidal agents. What are the characteristics and selection of these two types of agents?

The oxidative bactericidal and algicidal agent is a type of agent that makes the active enzyme inside the bacteria inactivated or directly oxidizes bacteria with strong oxidizing properties, causing bacteria to lose activity and is generally also used as a disinfectant. 

The common oxidative bactericidal and algicidal agents according to different action mechanisms are:

• Sequential chlorinated bactericidal agent (such as chlorine, sodium hypochlorite, chlorine tablets, etc.)

• Bromine and bromine compounds

• Chlorine dioxide

• Ozone

The principle of non-oxidative bactericidal and algicidal agents is not to kill bacteria by oxidation, but to act on a particular part of microorganisms as toxic agents, thereby destroying the cell or life-sustaining part of microorganisms to achieve bactericidal purpose. 

The common types of non-oxidative bactericidal and algicidal agents are:

• Quaternary ammonium salt/phosphonium salt

• Organic bromine

• Isothiazolone ketone class

• Phenol

• Organic aldehydes

• Heavy metal organic compounds

Advantages and disadvantages of oxidative bactericidal agents

• Fast bactericidal and algicidal speed, good bactericidal effect, high broad-spectrum bactericidal, low processing cost, relatively small environmental pollution, and microorganisms are not easily resistant to the drug, and easy to use.

• The disadvantage is that it is greatly affected by organic matter and reducing substances in water, the drug time is short, and it is greatly affected by the pH value in water. At the same time, the dispersion and penetration and peeling effects are poor.

Advantages and disadvantages of non-oxidative bactericidal agents

• It has high efficiency, broad spectrum, low toxicity, strong penetration, quick and long-lasting efficacy.

• It has penetration and peeling effects on sediment or sticky sediment, and is less affected by reducing substances such as hydrogen sulfide and ammonia, and is less affected by the pH value in water.

• However, the processing cost is relatively high compared with oxidative bactericidal and algicidal agents, and improper use may cause environmental pollution.

• Microorganisms in water can develop resistance to the drug, so it is necessary to alternate between different types of bactericidal and algicidal agents.

When choosing bactericidal and algicidal agents, considerations should be given to:

• The degree of microbial contamination in the water system and the type of bacteria;

• The pH value range of water quality;

• The size of water loss;

• The content of ammonia nitrogen or organic impurities in water, etc.;

• For specific product selection, it is necessary to choose based on actual conditions.
  

Non-oxidative bactericidal agents from Runxing Pharmaceutical

• Can quickly and effectively kill bacteria, algae, fungi, including Legionella pneumophila;

• Has excellent ability to control biological slime;

• Compared with traditional non-oxidative bactericidal agents such as isothiazolone ketone, it has a more effective ability to remove biological film;
  When used in conjunction with any oxidative bactericidal agent, it has a synergistic effect, which can significantly improve and further enhance the cost-effectiveness of the product;

• Fast killing speed and long-lasting effect.

Oxidative bactericidal agents from Runxing Pharmaceutical

• Can effectively kill bacteria, fungi and algae within a wide range of pH values without producing drug resistance;

• The product is in solid tablet form, which is easier to operate than gas or liquid bactericidal agents, reducing the risk of chemical accidents and environmental pollution;

• Compared with traditional chlorine bactericidal agents, it has stronger performance in water quality environments with severe organic pollution;

• Compared with chlorine-type oxidative bactericidal agents, it is safer and easier to operate, and the effect is better.