Article courtesy of atg UV Technology | July 23, 2015 | Environmental Expert | Shared as educational material
atg UV Technology has recently developed a chemical-free Advanced Oxidation Process (A.O.P.) known as Keratox for the treatment and removal of organic and chemical contaminants from municipal drinking water and wastewater.
Utilising atg UV Technology’s UV treatment systems in combination with a unique and patented Titanium Dioxide (TiO2) catalyst, the Keratox advanced oxidation solution can be used to target and remove contaminants in order to meet regulations such as the EU Priority Substances Directive (2013/39/EC), a new ‘daughter directive’ of the widely established Water Framework Directive (2000/60/EC) that will affect all European member states.
The Priority Substances Directive, and other associated watch lists for chemicals of priority concern will require up to 45 micro-pollutants such as Polycyclic Aromatic Hydrocarbons (PAH’s), Endocrine Disruptor Compounds (EDC’s), Alkylphenol’s and trace pesticides and pharmaceuticals to be removed from effluent wastewater streams before discharge into the environment. In addition, some municipal drinking water suppliers are also looking at implementing Advanced Oxidation Processes for contamination removal before potable drinking water enters their municipal water network.
A New Approach to Advanced Oxidation
Unlike traditional A.O.P. techniques that require chemical dosing with hazardous catalytic agents such as hydrogen peroxide or OPEX intensive ozone generation, the Keratox solution by atg UV Technology uses a specially engineered and novel ‘chemical-free’ TiO2 catalyst which reacts with the UV light to safely produce Hydroxyl Radicals, a highly reactive oxidant.
“Whilst Hydroxyl Radicals are an extremely reactive and effective at breaking down trace contaminants and micro-pollutants, they feature a very short life, and quickly break down into oxygen and water, posing no environmental risks.”
These Hydroxyl Radicals effectively break apart almost all organic and chemical contaminants into their base components of CO2 and H2O, allowing water to be treated to a very high standard at a significantly reduced cost.
A key feature of the Keratox solution is the ‘fixed’ nature of the TiO2 catalyst. Previous TiO2 Advox applications using UV required dosing with Titanium Dioxide powder or slurry in order to create the right surface area conditions for effective OH- radical yield. Whilst this method was an effective Advanced Oxidation Process, the cost and complexity of recovering the TiO2 catalyst made solutions unviable for large scale treatment applications.
In comparison, the Keratox A.O.P. solution offers a fixed in place, true catalyst that is not consumed by the process, and therefore has a significant advantage in lowering the operational costs when compared to Ozone and Hydrogen Peroxide. In addition as a chemical-free solution, no subsequent removal of any residual catalyst is required.
“By utilising a safe and fixed Titanium Dioxide catalyst, operators can eliminate the requirement to take delivery of, store and handle dangerous chemicals such as Hydrogen Peroxide. So far, the industry response to this new development has been amazingly positive, with 3 operators requesting pilot trials to go ahead this year as part of their commitment to the UKWIR chemical investigation programme.”
Barry Hopton, Municipal Sales Manager.
Furthermore, by using a ‘fixed’ TiO2 catalyst in place of agents such as Hydrogen Peroxide, the challenges associated with delivery, storage and handling of explosive and volatile chemicals can be eliminated. This both simplifies site operations and can significantly reduce the associated CAPEX and OPEX of a project.
Benefits of the Keratox Advanced Oxidation Solution
- Safe, low risk chemical-free technology
- Eliminates chemical transportation, storage and handling requirements
- Simple to use ‘turn-key’ solution
- Highly effective and proven technique for organic contaminant removal
- Very low operation & maintenance requirements
- Can significantly reduce TOTEX costs compared to other available technologies
- Identified as a Best Available Technique (BAT) for contaminated water
atg UV Technology are currently performing a number pilot studies using the Keratox TiO2 solution with UK municipal drinking water and waste water companies, as part of the CIP phase 2 initiative that is currently being undertaken by water companies across the UK. This analysis is looking to progress investigations further by conducting more site specific assessments and pilot trials of innovative treatment processes for trace substance removal.