Toxicity of coke wastewater treated with advanced oxidation by Fenton process supported by ultrasonic field

The aim of the presented study was to determine the toxicity of wastewater from the production of coke. The wastewater was treated with advanced oxidation involving ultrasonic field with Fenton’s reagent (the amplitude was 61.5 μm and sonication time 8 min). Two doses of iron and four doses of hydrogen peroxide were used. The amount of hydrogen peroxide was proportional to the value of the chemical oxygen demand of raw wastewater, ranging from COD/H₂O₂ ratio of 1:2.5 to 1:20. Two tests were used to determine the toxicity (algae growth inhibition test and Lepidium test). It was found that more toxic to algae was wastewater treated by Fenton’s reagent containing a higher dose of iron. A similar inhibitory effect was observed on the germination of cress seeds.