Advanced oxidation processes (AOP) for industrial water treatment applications including ground water remediation, wastewater treatment and pretreatment.  Oxidation processes are most often used to remove TOC, COD or specific organic compounds from water. Advanced oxidation processes (AOP) combine  (O3), ultraviolet ,  hydrogen peroxide  and/or catalyst to offer a powerful water treatment solution for the reduction (removal) of residual organic compounds as measured by COD, BOD or TOC. All AOP are designed to produce hydroxyl radicals.  It is the hydroxyl radicals that act with high efficiency to destroy organic compounds.  The chart below shows the oxidizing power of hydroxyl radicals versus other oxidants.

The advanced oxidation process (AOP) is successfully used to decompose many hazardous chemical compounds to acceptable levels, without producing additional hazardous by-products or sludge which require further handling. The term advanced oxidation processes refers specifically to processes in which oxidation of organic contaminants occurs primarily through reactions with hydroxyl radicals. AOPs usually refer to a specific subset of processes that involve O3, H2O2,and/or UV lightAdvanced oxidation processes are designed to both efficiently produce and use hydroxyl ions for these oxidation.  

They have a wide range of applications, mainly for oxidation of refractory compounds, TOC & COD reduction in:

• Gas effluent treatment
• water reclaim / reuse / recycling
• drinking water supplies
• industrial & municipal wastewater
• process water, ultra-pure water
• electronic & pharmaceutical industries
• medicinal baths, sanatoriums, hospitals
• cooling water systems

AOP can act on organic compounds in water in several ways: convert one compound into another (conversion), conversion with a reduction in toxicity and mineralization (breaking the organic down to CO2 and inorganic salts).  In some cases, discharge permits simply require conversion from a compound of interest to another compound that is not covered by the permit.  For example, some permits require taking phenol to a fraction of a ppm.  In other cases, permitting authorities require the toxicity of the compound/wastewater to be reduced prior to discharge.  In some cases, mineralization is needed as measured by a reduction of TOC.

Advantages of Advanced Oxidation Processes

• Rapid reaction rates
• Small foot print
• Potential to reduce toxicity and possibly complete mineralization of organics treated
• Does not concentrate waste for further treatment with methods such as membranes
• Does not produce materials that require further treatment such as "spent carbon" from activated carbon absorption
• Does not create sludge as with physical chemical process or biological processes (wasted biological sludge)
• Non selective pathway allows for the treatment of multiple organics at once

Disadvantages of Advanced Oxidation Processes

• Capital Intensive
• Complex chemistry must be tailored to specific application
• For some applications quenching of excess peroxide is required