Effects of phenolic compounds on TOC and nitrogen removal from potato wastewater using anaerobic-oxic-anoxic process

The objective of this study was to study the effect of TOC, ammonia, phenol, and 2,4-dichlorophenol on TOC removal, nitrification and denitrification rate. Experiments were conducted using anaerobic, oxic and anoxic reactors. Anaerobic reactor had volume of 500 ml and hydraulic retention time of 6 hours. Oxic reactor had volume of 1,000 ml and hydraulic retention time of 12 hours. Anoxic reactor had volume of 500 ml and hydraulic retention time of 6 hours. TOC concentrations of 100, 550 and 1,000 mg/l were used as low, medium and high concentrations respectively. Ammonia concentrations of 10, 55 and 100 mg/l were used as low, medium and high concentrations respectively. Phenol concentrations of 10, 55 and 100 mg/l were used as low, medium and high concentrations respectively. 2,4-dichlorophenol concentrations of 10, 55 and 100 mg/l were used as low, medium and high concentrations respectively. TOC was mainly removed in oxic reactor, anaerobic and anoxic reactors. Ammonia was produced in anaerobic reactor by solubilization and was mainly removed in oxic and anoxic reactors respectively. The percent TOC removal of anaerobic-oxic-anoxic reactor that treated phenol-contained wastewater was between 48.83 and 78.64 Percent. The percent TOC removal of anaerobic-oxic-anoxic reactor that treated 2,4-dichlorophenol-contained wastewater was between 69.13 and 91.89 Percent. The nitrification of oxic reactor that treated phenol-contained wastewater was between 0.36 and 4.49 mg/l-hr. The nitrification of oxic reactor that treated 2,4-dichlorophenol-contained wastewater was between 0.36 and 10.00 mg/l-hr. The denitrification of anoxic reactor that treated phenol-contained wastewater was between 0.35 and 6.17 mg/l-hr. The denitrification of anoxic reactor that treated 2,4-dichlorophenol-contained wastewater was between -225 and 9.55 mg/l-hr. When ammonia concentration increased, nitrification and denitrification rate increased, but it caused percent TOC removal decreased. When TOC concentration increased, percent TOC removal, nitrification and denitrification rate increased. Phenol caused more inhibition of TOC removal, nitrification and denitrification rate than 2,4-dichlorophenol.