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Updated: Jul 12, 2026

Estimating Sediment Denitrification Rates Using Cores and N2O Microsensors
Published on: December 6, 2018
Inhibitory effects of toxic compounds on nitrification process for cokes wastewater treatment
Young Mo Kim1, Donghee Park, Dae Sung Lee
1Advanced Environmental Biotechnology Research Center, School of Environmental Science and Engineering/Department of Chemical Engineering, Pohang University of Science and Technology, Pohang 790-784, South Korea.
Abstract:
Cokes wastewater is one of the most toxic industrial effluents since it contains high concentrations of toxic compounds such as phenols, cyanides and thiocyanate. Although activated sludge process has been adapted to treat this wastewater, nitrification process has been occasionally upset by serious inhibitory effects of toxic compounds. In this study, therefore, we examined inhibitory effects of ammonia, thiocyanate, free cyanide, ferric cyanide, phenol and p-cresol on nitrification in an activated sludge system, and then correlated their threshold concentrations with the full-scale pre-denitrification process for treating cokes wastewater. Ammonia below 350 mg/L did not cause substrate inhibition for nitrifying bacteria. Thiocyanate above 200mg/L seemed to inhibit nitrification, but it was due to the increased loading of ammonia produced from its biodegradation. Free cyanide above 0.2mg/L seriously inhibited nitrification, but ferric cyanide below 100mg/L did not. Phenol and p-cresol significantly inhibited nitrification above 200 mg/L and 100mg/L, respectively. Meantime, activated carbon was added to reduce inhibitory effects of phenol and free cyanide.
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