Why Use Chlorine Dioxide Against Biofilm Production?

The cooling systems used in industries to dissipate heat and keep the processes operational can be impacted by the presence of microorganisms, namely, algae, bacteria, and fungi. The major constituents of these organisms are the cell wall, nuclear material, and cytoplasm. To survive in any environment, the microorganisms must safeguard their cellular material, receive food, process food into cellular material and energy, reproduce, and excrete waste. The cell wall helps to keep the cellular material and synthesize energy, the cytoplasm, and nuclear material converts food to cellular matter, while the nuclear material alone helps in the reproduction of microorganisms. In cooling systems, these microorganisms exist in the form of algae and biofilm.

What is a biofilm and why is chlorine ineffective in removing it?

A biofilm comprises polymeric substances created by bacteria, which can be difficult to remove. The formation of bacterial biofilm or slime can create a lot of problems for the cooling systems used in industries. It can prevent the transfer of heat by cooling systems leading to increased cost of energy or loss in production. Bacterial biofilm may contain pathogens like Legionella and its rate of production depends on factors such as the available bacterial nutrients. Traditionally, chlorine is used to control slime, although ineffectively. This is due to the fact it chlorine does not penetrate the biofilm layer but works only at the surface. Also, if the available bacterial nutrient is more than the rate of biofilm removal, then the efficacy of chlorine can be telling.

Chlorine dioxide – the effective biocide

Chlorine dioxide is a multi-spectrum biocide that is effective in controlling biofilm over a wide pH range. Interestingly, it does not react with organic substances to produce Trihalomethanes (THMs) and Total Organic Halides (TOX). These chemical compounds are considered to be environmental pollutants and even carcinogenic, and their presence in public water systems can be detrimental to humans. Besides, Chlorine dioxide does not react with most chemicals such as scale and corrosion inhibitors that are present in the cooling systems. It is very effective in treating Biofilm Production in Buena Park and cooling systems having high pH and contaminated with ammonia-nitrogen.

Chlorine dioxide or ClO2 removes biofilm in cooling towers when applied correctly at a proportion of 0.6 – 1.0 mg/liter. Since it does not react with major biofilm constituents, it inactivates the bacterial biofilm by penetrating its cell wall. ClO2 can be applied intermittently (0.1 – 5.0 mg/liter) or continuously (0.1 – 1.0 mg/liter) depending on the degree of contamination in the cooling systems. For a one-minute contact time, the minimum residual concentration of ClO2 is 0.1 mg/liter.

How is ClO2 used to control biofilm

ClO2 happens to be in gaseous form and is created by activating sodium chlorite with an acid source or oxidizing agent. A chlorine dioxide generator converts sodium chlorite to ClO2 solution, which is then applied in a manner that allows proper mixing and distribution. However, the feed point should remain well below the water level in the cooling towers to prevent volatilization of the compound. Being a powerful oxidizing agent, ClO2 destroys compounds that produce algae-related taste and odor. It removes prophylaxis on slimes effectively.

Conclusion  

The multi-spectrum usage of chlorine dioxide as an effective disinfectant against biofilm Production in Buena Park and other cooling water systems has brought it into the limelight. Its cost-effectiveness and myriad benefits such as the ability to remove iron and magnesium compounds, no generation of chlorine byproducts, and non-reactivity with most organic compounds, among others, has made it the go-to disinfectant for enterprises.