The future of AOP is green thanks to on-site generation of hydrogen peroxide

Water pollutants such as pharmaceuticals and pesticides are very hard to remove from the water, and an increasing number of water treatment operations are looking at eliminating those.

Advanced oxidation processes (AOPs) are an essential part of the treatment chain. AOPs are used to remove harmful trace substances that find their way into the water cycle – for example, through the use of pharmaceuticals, personal care products, surfactants, pesticides, flame retardants, and others – and that would accumulate to critical concentrations in drinking water if not removed. In addition to eliminating micropollutants, established AOPs act as an effective disinfection barrier against viruses, bacteria, and protozoa.

AOP is based on combining hydrogen peroxide (H₂O₂) with either ultra-violet light or ozone to eliminate hard-to-break pollutants from water.

Advantages of Peroxide UltraPure

The HPGen uses only air, electricity and water as inputs to produce 99.999% pure hydrogen peroxide directly on site. This is done through HPNow’s patented on-site peroxide generation technology, the first such technology in the world to be used commercially in water treatment. The output Peroxide UltraPure can be used in conjunction with a UV reactor in an advanced oxidation process, to remove all trace organic compounds from water.

• Chemical-input free: Advanced oxidation solutions typically require transport, handling, storage and management of toxic chemicals on site. The HPGen, on the other hand, provides a solution that’s chemical-input free: The output hydrogen peroxide, known as Peroxide UltraPure, is water-soluble. Output and in-line concentration are readily measurable and controllable.
• Sustainable: Peroxide UltraPure is the greenest form of hydrogen peroxide. It is made from water, electricity and air. When renewable electricity is used, there are absolutely no CO₂ emissions from the generation process. HPGen uses no stabilizers, produces over 99.999% pure hydrogen peroxide solution, and breaks down to pure water and oxygen, leaving no by-products behind.
• Safety: Peroxide UltraPure also gives a boost to safety in AOP. HPGen produces safe, high-purity, low-concentration hydrogen peroxide – it’s no longer necessary to store and handle dangerous chemicals thanks to the hydrogen peroxide being produced directly at the point of use.
• Supply security: HPGen works automatically and with no need for user intervention – it is remotely monitored, making it essentially plug-and-play. Instead of having to rely on a volatile hydrogen peroxide supply chain, users are generating the peroxide required by the advanced oxidation process themselves.

Field results

To demonstrate the safe and reliable integration of this technology into a typical water treatment scheme using a UV AOP solution, such a facility was installed at world-leading chemical company Evonik’s premises in Germany. The test plan focused on evaluating the removal efficacy of four emerging contaminants using the unique combination of in-situ H₂O₂ and UV. HPNow’s HPGen on-site H₂O₂ generator was integrated with Xylem’s WEDECO low-pressure UV reactor.

Ibuprofen, caffeine, dichlorobenzamide, and 1,4-Dioxane were spiked to the process water as target pollutants. Both test series with 5 and 10 mg H₂O₂/L showed good to very good degradation results of all substances. In both tests, the same pattern was revealed with the strongest reduction of ibuprofen, followed by caffeine, dichlorobenzamide, and finally, 1,4-Dioxane, with the double H₂O₂ dose increasing the log reduction by a factor of about 1.4.

This joint project, combining the expertise, products, and technologies of Xylem, HPNow, and Evonik, shows that an advanced and environmentally friendly technology can be implemented while eliminating the need to transport, store, and handle high-concentration peroxide.

Of no less importance is the positive impact on sustainability. A substantially reduced carbon footprint is achieved through the combination of highly efficient direct electrochemical generation, as well as the elimination of transportation emissions. In fact, with the use of green electricity, HPGen-UV’s operational carbon footprint can be reduced to zero – and no input chemicals are used.

Another field test, carried out in conjunction with Netherlands-based PureBlue, showed that by combining an HPGen system together with PureBlue’s UV chamber, chemical-input free UV – Peroxide AOP breakdown of trace organic compounds can be achieved.

Results showed that the combination of HPGen’s on-site generated Peroxide UltraPure™ and PureBlue’s UV proven to be as effective, and at times more effective, as compared to bulk peroxide.

Angelo de Mul, General Manager at PureBlue, commented: “The combination of HPGen hydrogen peroxide generated directly on site, and PureBlue UV enables a much safer and reliable advanced oxidation process, with reduced costs in labor, infrastructure, and chemical inputs. These represent great benefit to our customers and partners.”

Peroxide UltraPure, generated directly on site with the groundbreaking HPGen technology, is a green oxidant. It enables safe and chemical-free AOP, and breaks down to pure water and oxygen following use. Using Peroxide UltraPure in conjunction with a UV reactor, creates a powerful, sustainable combination that results in clean water.