Highly active organic substances, such as pharmaceuticals, biocides, pesticides and their metabolites, are increasingly being found in wastewater. Mostly, the substances are pharmaceutical residues introduced by consumers. Industrial wastewater can also be contaminated with highly active substances. Advanced oxidation is a process that reliably destroys these highly active substances and thus purges them from the wastewater.
EnviroChemie implements the advanced oxidation process in various oxidation procedures in its proprietary Envochem® AOP product range. The process involves the use of ozone or hydrogen peroxide combined with Fenton's reagent or UV radiation (UV oxidation). Fenton's reagent is a sulphuric acid compound consisting of an iron salt – usually iron(II) sulphate (FeSO4) – and hydrogen peroxide, which acts as a strong catalyst for oxidizing organic substrates. UV radiation converts the hydrogen peroxide into highly reactive hydroxil radicals that oxidize the contaminants in the water. The contaminants are converted mainly into carbon dioxide, water and salt. Ozone is also used in the advanced oxidation process, depending on the task and contaminants to be destroyed in the wastewater.
Limit compliance thanks to AOP
In recent years, for example, UV oxidation systems have proven their ability to destroy pharmaceutical agents and are becoming increasingly commonplace. Extensive preliminary investigations in laboratory or pilot tests are a prerequisite for the good and cost-efficient performance of AOP, particularly in UV systems which use hydrogen peroxide as an oxidant. Beside the active ingredients, pharmaceutical wastewater can contain a variety of organic compounds that can be easily treated in the company's own sewage treatment plant or the municipal sewage treatment plant. Depending on the strength of the total organic load (COD: chemical oxygen demand), the oxidant is increasingly consumed by the organic substances which are not actually intended for reduction. The precise selection and combination of the appropriate UV radiation sources, the design of the UV reactor overflow, the dosage of the oxidant and the treatment duration are important for a good and cost-efficient AOP.