Pros and Cons of the Advanced Oxidation Process - Genesis Water Technologies

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Pros and Cons of the Advanced Oxidation Process - Genesis Water Technologies

In many water and wastewater treatment applications, there are a number of pollutants that are difficult to reduce by physical, chemical, or biological means alone. In more recent years, there has been a growing concern regarding pharmaceutical drugs in drinking water and aquatic environments. Pesticides get caught in runoff from farms into freshwater supplies. Personal care products are typically washed down the drain into whatever system they are linked to. Landfill leachate is a toxic cocktail of compounds that can leak into groundwater sources.Such contaminants fall into the category of micropollutants, because they are so small. Their size alone is part of the reason, they are so difficult to remove from water and wastewater by certain means. More efficient removal requires a more powerful oxidation process, this process is called an advanced oxidation process (AOP).

This process creates powerful oxidizing agents in the form of hydroxide (OH–), but more specifically, its neutral variant the hydroxyl radical (⦁OH). Its oxidation potential is twice that of chlorine, a commonly used disinfectant. Hydroxyl radicals are the driving forces behind many advanced oxidation processes. Ozone (O3), hydrogen peroxide (H2O2), and ultraviolet light (UV) are often used in various combinations to produce ⦁OH in sufficient quantities to degrade organic (and some inorganic) pollutants. This process can reduce these pollutant concentrations, potentially from hundreds of parts per million (ppm) to just a few parts per billion (ppb).

These radicals are non-selective, therefore, they attack almost all organic materials. After these contaminants are broken down once by the ⦁OH radical they form intermediates. Those intermediates themselves react with the oxidants and mineralize into stable compounds.

Advanced oxidation has been around for several years. Therefore, this process has more than proved its usefulness, however, it is still being researched and optimized accordingly.

A powerful treatment process like the advanced oxidation process has many benefits, but it also has its share of disadvantages. Below are some of the pros and cons of this process....

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5 Comments

  2. in my opinion and experience, treatment should be with robust biological systems, like SBR (we often successfully apply fixed level, plug flow SBR) or MBBR, to be supplemented, if needed, by an AOP process for recalcitrant COD.

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  3. AOP has its distinct space in water treatment. One who chooses AOP has clear idea in his mind that he wants to avoid several uncertain chemical and biological dosing. He also should be clear that despite of high cost and little more energy, he is yielding safe water. To my personal experience working exclusively with AOP in India with most hazardous industrial waste waters, I can certify that OPEX for AOP is at least 10% less than any conventional or advanced non AOP process on per Kg COD settlement basis.  Every coin has two sides and Nick Nicholas is bold enough to highlight the grey side of the AOP coin. But don't forget, coins don't loose their value even when they are little dirty!

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    1. Thanks Niraj, yes I wanted to be balanced in addressing both the positive as well as some negative aspects of this AOP process. However, you are correct that coins don't loose their value when they are a little dirty! The AOP benefits outweigh the disadvantages especially in certain industrial waste waters. At GWT, we work with our local partners using the AOP process were appropriate for industrial waste water applications.

  4. You forgot to mention expensive, inefficient and energy intensive.  There are alternatives to produce safe water. There are situations where it is appropriate, but keep in mind that you are using a lot of energy to knock off a couple of micrograms of something in a sea of TOC, unless it is applied post RO.

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    1. Joseph, I think you comments are not well founded. There are several applications in which an AOP process in cost efficient and effective. Especially, in terms of emerging contaminants in drinking water (PFAS,1,4 dioxane...) and within industrial wastewater applications. Of course, as I mentioned each treatment process has its pros and cons - this is how GWT works with its clients and partners to utilize the most suitable treatment process for the application.