EnviroChemie White Paper – Removing trace substances from industrial wastewater using advanced oxidation processes (AOPs)
White Papers | EnviroChemie GmbH
The White Paper reviews the various uses of AOPs for the pre-treatment of wastewater concentrates covering a range of industries and applications, from eliminating toxic substances such as pesticides to neutralizing odors.
It explains the mechanisms by which AOPs can convert toxic materials into non-toxic ones and break down tightly bound substances into biologically degradable/recyclable ones, showing the power of hydroxyl (OH) radicals as oxidizing agents, reacting between a million and a billion times faster than ozone or hydrogen peroxide.
The paper then goes on to review a range of AOP technologies that can be used to form OH radicals:
- Ozone (O3): a very powerful oxidizing agent, long used as a disinfectant in water installations and swimming pools, that can react with substances both directly in acidic environments and indirectly in alkaline ones, where it forms hydroxyl radicals (OH•) that are short lived but less selective in effect, breaking down even complex compounds.
- Ultra violet with Hydrogen Peroxide (UV / H2O2: combined technology using UV lamps to activate the relatively cheap oxidizing agent hydrogen peroxide into forming highly reactive OH radicals with enhanced oxidizing effect. Hydrogen peroxide in aqueous solution can be handled easily and safely. Because of its non-selective oxidative effect, UV/H2O2 technology has a wide scope of applications and is easily scalable.
- Fenton reaction (H2O2/Fe2+): reacting hydrogen peroxide with an iron salt such as iron(II) sulfate (FeSO4) causes formation of OH radicals in aqueous solution. The method is widespread in the field of wastewater treatment and is easy to control, with simple equipment and facility operation and low energy demands.
- Photo-Fenton reaction (H2O2/Fe2+/UV): is a variant that applies ultra-violet radiation to accelerate the Fenton process, causing regeneration that reduces used quantity of Fe2+. In doing so it overcomes the main drawbacks of the Fenton process by reducing consumption of chemicals and sludge production.
The final section of the White Paper outlines practical examples of AOP wastewater treatment from the pharmaceutical and chemical industries, including;
- Modular UV/H2O2wastewater treatment facility to treat the water left over from tablet production that contains various APIs
- Ultra-compact and highly automated ozone-based continuous treatment of large volumes of wastewater from a cancer drugs production facility in Mexico
- UV/H2O2 treatment at a German fine chemicals company of wastewater that is highly polluted and acidic and high in phenolic compounds with a solution that allows wastewater could be fed into the facility’s own water treatment system
- Proposed photo-Fenton treatment solution for processing highly polluted and acidic wastewater at a German fine chemicals company that contains carcinogens, has a pH value below 1 and is jet black in appearance with chemical oxygen demand (COD) greater than 100,000 mg/l.