Chlorine dioxide vs. chlorine bleach: A battle of misconceptions

October 18, 2018

Chlorine bleach: It’s convenient to purchase. It’s cheap. It’s a well-known household cleaner and disinfectant. But is it best to use as a water sanitizer in the poultry house?

Treating with chlorine is a common method to sanitize poultry drinking water and reduce concentrations of waterborne pathogens, such as bacteria, viruses, molds and protozoans.

“The effectiveness of chlorine is dependent on water quality and pH of the water,” said Neogen poultry expert Lindsay Good. “Chlorine tends to bind itself to any organic material in the water, reducing its potency. Chlorine is also less effective if the water pH is higher than 7.0.”

The use of chlorine is not limited to only water line treatments, though. Because of its effectiveness in cleaning and disinfection, chlorine bleach is often used in many household and industry settings. This overuse has led to a rise in chlorine-resistant pathogens (Table 1) that can cause issues in a flock of birds.

Table 1: Chlorine-resistant pathogen list

Acanthamoeba castellani1 Echovirus10 Norwalk Virus3
Actinomycetes2 Eikelboom type 021N13 Polio virus3
Adenovirus3 Entamoeba histolytica14 Pseudomonas aeruginosa6
Aspergillus niger4 Giardia15 Rhodotorula flava20
Bacillus Lichenformis5 Gram Positive spore forming bacilli2 Rotavirus20

Bacillus Subtillis6 Hepatitis A16 Salmonella enterica Serovar Typhimurium DT10421
Biofilm Bacteria6

Klebsiella pneumoniae17 Snow Mountain Agent Virus3
Campylobacter jejuni7 Listeria monocytogenes18 Tetrahymena pyriformis1
Clostridium botulinum8 Methylobacterium19 Thiothrix spp.13
Clostridium perfringens9 Micrococci2 Toxoplasma gondii22
Coxsackie Virus10 Mycobacterium chelonei20 Vibrio Chlolerae21
Cryptosporidium11 Mycobacterium fortuitum20 Yersinia enterocolytica4
E. coli12 Noroviruses3  

*This is a list compiled from readily available, peer-reviewed research. It is not a full list and not all strains of all pathogens are resistant to chlorine, but all listed pathogens do have chlorine-resistant strains.

Often mistaken for chlorine, chlorine dioxide is a similarly-named chemical also used for treating drinking water. Chlorine dioxide has several advantages over chlorine:

    • Chlorine dioxide is a more effective sanitizer in poor quality water containing high levels of organic matter and other dissolved solids.
    • Chlorine dioxide effectively operates in a broader range of pH levels (4 to 10).
    • Chlorine dioxide is faster-acting than chloride, especially if water pH rises.
    • Chlorine dioxide has 2.6 times the oxidative power of chlorine bleach.

“In its pure form, chlorine dioxide is an unstable gas that is difficult to safely transport,” said Good. “For this reason, it’s sold as a stabilized liquid. The stabilized chlorine dioxide is activated on-site when it is injected, along with an acid, into the water line. This mixing occurs in a closed system — the water line — and safely generates chlorine dioxide gas.”

Installing a dosing system to inject the chlorine dioxide and activator chemical is relatively straightforward. Low-cost electric metering pumps pull the stabilized dioxide and the activation chemical directly from their containers. The products can be injected into a small reaction tee or directly into the water line. This ensures consistency of the treatment, safety of the producer, and extends the life of the applicators.

Understanding the differences between chlorine bleach and chlorine dioxide is important to providing birds properly disinfected water.

This post is part of our series on water lines in the poultry house. See the rest of the articles here.


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Category: Animal Safety, Poultry, Animal Health, Water Treatment