Most commonly used water disinfectants reviewed: an honest opinion

The majority of businesses are continuously trying to improve the way they run their organisations; tightening up processes. Introducing more cost effective solutions or technologies to existing procedures can play a key role as part of these improvements.

Implementing new technologies into an existing company can be a big decision, especially if things are actually working ‘OK’– why fix something when it’s not broken, right?

What about technologies that have not yet been widely adopted? This is when the apprehension could kick in and you revert back to ‘OK’

In a time with fierce global competition in all industries ‘OK’ is not enough

Do the water disinfection methods applied in your business need reviewed?

Could there be potential for a new, more sustainable solution?

We want to ensure that you are armed with all the information you need to make the right decisions for your company.

In this article we are going to look at six disinfectants in the water industry and how effective they are in comparison to each other.

All disinfectants are the same, right?

Wrong.

Every pathogen (a bacterium, virus, or other microorganism that can cause disease) has a variable resilience so the disinfectants used to combat them needs to be strong enough to ‘kill’ or ‘inactivate’ the pathogen.

Each one of these disinfectants comes with advantages and disadvantages, and certain disinfectants may be more suitable for a particular application than its counterpart.

The ‘kill rate’ of each substance indicates how quickly after contact the disinfectant renders the pathogen harmless.

Some disinfectants leave a useful persistent disinfecting affect, ‘killing’ pathogens even after the application process is complete. This is called ‘Residual Kill’. Without a residual kill pathogens can rapidly reinfect the water and cause a danger to consumers.

How effective is my disinfectant?

In this video, we are going to compare six commonly used disinfectants, highlighting some of their key advantages and disadvantages.

What are the advantages  and disadvantages with using Sodium Hypochlorite as a water disinfectant? 

Advantages

• Disinfection with sodium hypochlorite has similar disinfectant efficiency and residual performance as chlorine gas, but reduces the hazards associated with the handling and storing of chlorine gas especially if generated on-site
• As with chlorine gas, it is relatively cheap and can economically disinfect small to large amounts of water.

Disadvantages

• Although safer to handle than chlorine gas, NaOCl is still a hazardous and corrosive substance.
• At the standard supplied concentration (14%), storage and handling of NaOCl requires process safety procedures and containment. This is to avoid exposure to workers and the environment and to prevent loss of potency through exposure to air, which causes it to deteriorate.

What are the advantages  and disadvantages with using Ozone (Trioxygen or O3) as a water disinfectant?

Advantages

• Ozone O3 produces less THM disinfection by-products than result from chlorine
• Ozone O3 is also highly efficient at killing bacteria, viruses, and protozoa and is always generated on-site.  It does not require transportation or storage of dangerous materials

Disadvantages

• Because of its toxicity, this chemical needs to be consistently monitored
• Within the ozone system there are higher than fatal concentrations of ozone and the release of this gas would clearly be highly dangerous

What are the advantages  and disadvantages with using Chloramine as a water disinfectant?

Advantages

• Chloramine is one of the weaker disinfectants in this comparison but is more stable, and thus provides longer lasting residual disinfectant which can be an advantage for distribution systems.
• Like other chlorine types it is relatively inexpensive and simple to use.

Disadvantages

• On-site generation of monochloramine requires chlorine gas or hypochlorite, which means that the safety precautions associated with chlorine apply.
• As monochloramine is a weak disinfectant, especially against cysts and viruses, the contact times required for adequate primary disinfection are much longer and higher than with chlorine and because of this chloramines are not generally chosen for primary disinfection

What are the advantages  and disadvantages with using Chlorine Dioxide (ClO2) as a water disinfectant?

Advantages

• It is a more effective disinfectant than chlorine having an efficacious effect on bacteria, viruses and cysts, but is not as strong an oxidant as free chlorine.
• Some of the most recent generating systems do not require chlorine gas transport or handling

Disadvantages

• Often, chlorine dioxide will be generated onsite from sodium chlorite and chlorine gas, and thus requires all of the precautions associated with the transportation and handling of chlorine gas
• Chlorine dioxide production using chlorine gas or acid and hypochlorite generally requires an excess of chlorine or acid to maximize sodium chlorite conversion

What are the advantages  and disadvantages with using Calcuim Hypochlorite as a water disinfectant?

Advantages

• Calcium Hypochlorite has excellent stability when kept in dry storage, maintaining its potency over time.
• This compound is relatively stable, is similar to sodium hypochlorite in disinfection properties and has greater available chlorine than sodium hypochlorite (liquid bleach).

Disadvantages

• Because the chemistry is so similar to chlorine gas and NaOCl (“liquid chlorine”), this method offers no disinfection efficiency advantages (i.e., Giardia and Cryptosporidium kill rates) nor disinfection by-product advantages.
• It is corrosive and hygroscopic (i.e., readily absorbs moisture from the air), reacting slowly with moisture in the air to form chlorine gas if not stored in air-tight containers.

What are the advantages  and disadvantages with using ESOL Electrolyzed water as a water disinfectant?

Advantages

• Since the technology uses only salt (NaCl) and water as feed to generate the electrolyzed water on-site, no toxic chemicals are handled or transported, thus reducing process safety compliance requirements.
• ESOL™ electrolyzed water process results in THM (trihalomethane) levels considerably lower than those produced by treatment with chlorine gas.

Disadvantages

• The process produces some disinfection by-products, which, though significantly reduced compared to chlorine gas, may require attention as the increasingly stringent regulations scheduled for the future are implemented.

More about the highest scorer - ESOL electrolyzed water

Electrolyzed water is NOT new.

Electrolyzed water was discovered back in 1834 but the concept was underdeveloped until after World War Two when the Russians and Japanese started carrying out studies in the 1950’s. The technology is now studied worldwide and has been scientifically accepted as an excellent method of disinfecting.

In the water disinfection process, electrolyzed water has been successfully introduced in private water supplies, outperforming traditional disinfectants such as Chlorine, without the associated drawbacks.

Bridge Biotechnology manufactures ESOL™ generators and then you, the customer, have complete control over the production and application of the electrolyzed water.

Each generator is built to a tried and tested specification however; ESOL™ electrolyzed water can be made to different oxidizing strengths by adjusting the cell current of each generator using a simple to use control panel.

Depending on the intended project, ESOL™ electrolyzed water can be applied in a number of different ways:

• Fogged
• Misted
• Sprayed

Effective biocidal action of any given active agent is reliant on:

• Concentration
• Exposure time
• Composition of the contact surface (with rough and/or absorbent surfaces requiring a longer contact time)
• Presence of organic loading

It is important to utilise a delivery mechanism that will maximise the ‘kill potential’ of ESOL™ electrolyzed water

Due the plethora of problems that ESOL™ can solve means that there needs to be various options for the application of the liquid.

Related content: How can ESOL electrolyzed water be applied?

What next?

So what things could be holding you back from making the change?

We have highlighted several advantages and disadvantages of six major disinfectants within the water industry.  The next stage is up to you;

We have compared six disinfectants in this article however if you want more information on these and other methods check out our other articles:

Related content: 

ESOL Electrolyzed water - advantages and disadvantages in the water industry

Ultraviolet (UV) Light - advantages and disadvantages in the water industry

Ozone (trioxygen or O3) - advantages and disadvantages in the water industry

Chloramination - advantages and disadvantages in the water industry

Chlorine Dioxide - advantages and disadvantages in the water industry

Calcium Hypochlorite - advantages and disadvantages in the water industry

Bleach (Sodium Hypochlorite) - advantages and disadvantages in the water industry

Chlorine Gas - advantages and disadvantages in the water industry

Would you like to introduce an environmentally alternative to chlorine into your business?

Are you ready to take the next step to improve your disinfection process?

Likewise; has this article left you with other questions?

Dive into our frequently asked questions section

We would love to hear from you and help you further