On-Site Generation Of Cleaning Solutions

Also known as OSG, the on-site generation of cleaning solutions is often referred to with multiple — and sometimes confusing — terms.

By Allen P. Rathey

“On-site generation” of cleaning solutions is among the terms applied to systems that produce cleaning chemicals on-site without adding conventional chemicals or chemical concentrates sourced off-site. Also known as OSG, the on-site generation process is often referred to with multiple (and often confusing) terms. These terms include: chemical-free; engineered water; electrolyzed water; activated water; and electrochemically-activated solution.

Clarifying On-Site Generation Terms

Chemical-free. OSG is not chemical-free, but rather moves the production of chemicals to the facility where they will be used. Since OSG does not rely on conventional packaged cleaning chemicals, it is “free” of those; however, since it makes chemical solutions on-site, “chemical-free” is a misnomer.

Engineered Water. Since engineering along with chemistry and physics principles are involved in OSG, this term is better but still misleading as the end result is not water, but a chemical solution.

Electrolyzed Water. This term describes the electrolysis of water that happens when electricity passes through water to which an electrolyte is added. The electrolyte, most commonly salt, typically enables conducting electricity through water in a controlled manner to convert it into an alkaline cleaning solution or mildly acidic sanitizing solution (i.e., a cleaning chemical and no longer water). The resulting solutions can be blended or split. Acidic and alkaline refer to the pH (scale of 0-14) of the solution. Cleaning/degreasing solutions typically have a higher pH, above 7 and are considered alkaline. Sanitizer/disinfectants typically have a lower pH, below 7 and are considered acidic.

Activated Water. This is water that has been activated through electrolysis to produce cleaning solutions. This developed a bad name in some circles because, in one form, it denoted non-augmented tap water (in which no salt or other minerals were added) that was altered by passing an electrical current through tap water. The main problem for consistency-of-solution was the inability to control the tap water, which varies in mineral content. Minerals (e.g., salt) serve as an electrolyte or conductor of electricity (i.e., tap water with adequate mineral content can be properly electrolyzed but tap water without sufficient dissolved minerals cannot). In summary, non-augmented tap water yields inconsistent “activation” that may or may not be effective.

cleaning solutions
Diagram illustrating example of the ElectroChemical Activation process (Image: PathoSans)

ElectroChemically-Activated, or ECA Solution. ECA controls water pH by first “softening” or conditioning water, augmenting it with salt, then splitting the resulting mildly acidic and alkaline cleaning solution streams using sophisticated membranes that remove most of the salt to result in very pure solutions. ECA is an advancement over common “electrolyzed water” that blends the streams. This is because the process splits the cleaning from the sanitizing or disinfecting streams and stores them in separate tanks for on-demand use; solutions remain effective for 30 days or more. Blending streams potentially dilutes performance and may lead to degradation of active ingredients.

ECA Efficacy And Selection

Once water is prepared for ECA, the electrolytic cell design, membrane configuration, and system transport of water through the cell and membranes determines the effectiveness of output solutions.

In general, on the alkaline cleaner side, facility managers should look for Green Seal certified GS-37 ECA solutions, since this certification validates sustainability aspects, and requires ECA solution cleaning performance to match conventional cleaning chemicals.

On the acidic or disinfecting side (the stream containing a mild form of hypochlorous acid), ask for test data related to kill claims and dwell time. Some ECA system companies also have EPA Registration on their bottled solutions to verify sanitizing and disinfecting claims.

It’s suitable for ECA to replace general purpose cleaners and disinfectants, but not to replace solvents for heavy petroleum based grease removal, graffiti or gum removal, acid bowl cleaners, or floor strippers.

A form of EPA Regulation applies to devices, since companies making ECA water producing devices can apply for an EPA Establishment Number. EPA requires Establishment Number bearing manufacturers to have kill claim data available, though device regulation is not nearly as rigorous as EPA Registration of standard chemical disinfectants. In general, EPA Registration applies to bottled-and-sold solutions, not devices, and this helps validate germ-kill claims. In this context, this is the most stringent form of EPA Regulation.

cleaning solutionsRathey (arathey@outlook.com) is an educator specializing in healthy facilities. He is current president of The Healthy Facilities Institute, and past-president of The Housekeeping Channel and The Healthy House Institute. He is also the principal of Winning Environments, LLC, promoting best practices that enhance living, working, and learning environments.

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    I thought the diagram used to describe on-sight generation was brilliant. At a glance I was able to easily understand the process of how it works.
    Rex Morrison
    Process Cleaning for Healthy Schools

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