ADVANCED OXIDATION PROCESSES (AOP)

The Advanced Oxidation Processes (AOP) are a technology developed for the removal of organic contaminants that are not treatable by conventional means due to their strong chemical stability and/or low biodegradability. The combination of two or more oxidants enables them to interact synergistically, resulting in further degradation of organic matter. The AOP have a high oxidative potential due to the Hydroxyl radicals, which transform these compounds to innocuous products such as CO2 and H2O. Despite the usual high costs of the chemical oxidation for complete mineralization, its combination with biological processes greatly reduces the operating costs.

º    FENTON

Uses a combination of hydrogen peroxide and a ferrous catalyst to produce OH radicals, responsible for the oxidation of organic compounds in the water

º    OZONATION (O3)

This process involves the use of ozone, O3, as an oxidizing agent. Ozone represents an attractive alternative for the oxidation process due to its high reactivity, which makes its oxidizing power greater than that of chlorine without producing THMs, and leaves no residues as it degrades into oxygen. TECNIAGUAS® Ozone Contact Towers maximize the contact surface between water and gas so that the volume of required ozone and the contact time between them are minimized. Ozonation can be combined with hydrogen peroxide, which accelerates the decomposition of ozone and the formation of OH radicals.

º    HYDROGEN PEROXIDE (H2O2)

Hydrogen peroxide has a higher oxidizing potential than chlorine, chlorine dioxide and potassium permanganate, being only exceeded by ozone. The objective of the Advanced Oxidation Process, in relation to hydrogen peroxide, is to produce free oxygen radicals by combining peroxide and ozone or UV. The result is a robust process that leaves no residues and achieves the degradation of substances that wouldn’t oxidize by conventional methods.

º    UV

The objective of the UV systems is to transfer electromagnetic energy from a device to the genetic material of organisms associated with water pollution, disabling their reproductive functions. TECNIAGUAS® can provide UV units with Hydro Optic Disinfection (HOD) technology, which uses the same principles as fiber optics to uniformly distribute the UV load inside a disinfection chamber. This technology ensures no water contamination with mercury or glass particles, in the event of mechanical failure of the lamps, because these devices are located outside the disinfection chamber and are not in contact with the water.

º    ADVANCED ELECTRO-OXIDATION (H2O2/UV/O3/CATALYSTS)

Advanced Electro-Oxidation is based on the generation of free OH radicals through the synergy between hydrogen peroxide, UV radiation, ozone and catalysts, coupled with the electrochemical action of two electrodes that simultaneously catalyze the reactions and oxidize the organic load within an electrolytic cell. This technology is suitable for the oxidation of compounds that are not treatable by conventional biological processes under normal conditions, such as phenols, cyanides and dissolved organic matter.

º    PHOTOCHEMICAL OXIDATION

* Vacuum UV (VUV) photolysis of water

* UV/H2O2

* UV/O3

* Photo-Fenton

* Heterogeneous Photocatalysis

º    WET AIR OXIDATION (WAO)

The Wet Air Oxidation process is based on the mixture of untreated water with pressurized air at elevated temperatures, between 115 and 300°C. The air acts as an oxidizing agent for organic compounds that are present in water, which produces the degradation of the liquid phase.

º    CATALYTIC WET AIR OXIDATION (CWAO)

A catalyst is added to the WAO process, which reduces the required temperature for the degradation. The temperature needed for the CWAO process ranges between 15 and 60ºC.

º    CATALYTIC WET PEROXIDE OXIDATION (CWPO)

The CWPO process combines the WAO with hydrogen peroxide in the presence of an iron catalyst. This system provides an interesting alternative for the pretreatment before a conventional biological system in order to reduce the toxicity and concentration of non-biodegradable compounds.