Investigating the inhibitory effect of cyanide, phenol and 4-nitrophenol on the activated sludge process employed for the treatment of petroleum wastewater.
In this work, the inhibitory effect of cyanide, phenol and 4-nitrophenol on the activated sludge process was investigated. The inhibition of the aerobic oxidation of organic matter, nitrification and denitrification were examined in batch reactors by measuring the specific oxygen uptake rate (sOUR), the specific ammonium uptake rate (sAUR) and the specific nitrogen uptake rate (sNUR) respectively. The tested cyanide, phenol and 4-nitrophenol concentrations were 0.2-1.7 mg/L, 4.8-73.1 mg/L and 8.2-73.0 mg/L respectively. Cyanide was highly toxic as it significantly (>50%) inhibited the activity of autotrophic biomass, heterotrophic biomass under aerobic conditions and denitrifiers even at relatively low concentrations (1.0-1.7 mgCN-/L). The determination of the half maximum inhibitory concentration (IC50) confirmed this, since for cyanide IC50values were very low for the examined bioprocesses (<1.5 mg/L). On the other hand, the IC50values for phenol and 4-nitrophenol were much higher (>25 mg/L) for the tested bioprocesses since appreciable concentrations were required to accomplish significant inhibition. The autotrophic bacteria were more sensitive to phenol than the aerobic heterotrophs. The denitrifiers were found to be very resistant to phenol.
School of Engineering, Chemical Engineering Department, Environmental Science & Technology Group (ESTg), Nazarbayev University, 53, Kabanbay Batyr Ave., Astana 010000, Kazakhstan.
V J
VJ
Inglezakis
Department of Water Resources and Environmental Engineering, School of Civil Engineering, National Technical University of Athens, 5 Iroon Polytechniou St., Zographou Campus, 15780 Athens, Greece. Electronic address: malamis.simos@gmail.com.
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S
Malamis
School of Engineering, Chemical Engineering Department, Environmental Science & Technology Group (ESTg), Nazarbayev University, 53, Kabanbay Batyr Ave., Astana 010000, Kazakhstan.
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A
Omirkhan
School of Engineering, Chemical Engineering Department, Environmental Science & Technology Group (ESTg), Nazarbayev University, 53, Kabanbay Batyr Ave., Astana 010000, Kazakhstan.
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J
Nauruzbayeva
School of Engineering, Chemical Engineering Department, Environmental Science & Technology Group (ESTg), Nazarbayev University, 53, Kabanbay Batyr Ave., Astana 010000, Kazakhstan.
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Z
Makhtayeva
School of Engineering, Chemical Engineering Department, Environmental Science & Technology Group (ESTg), Nazarbayev University, 53, Kabanbay Batyr Ave., Astana 010000, Kazakhstan.
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T
Seidakhmetov
School of Engineering, Chemical Engineering Department, Environmental Science & Technology Group (ESTg), Nazarbayev University, 53, Kabanbay Batyr Ave., Astana 010000, Kazakhstan.
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A
Kudarova
D019149:Bioreactors; D003486:Cyanides; D009584:Nitrogen; D009596:Nitrophenols; D010578:Petroleum; D019800:Phenol; D010636:Phenols; D012722:Sewage; D014865:Waste Disposal, Fluid; D062065:Wastewater; D018508:Water Purification
D003486:Cyanides; D009584:Nitrogen; D009596:Nitrophenols; D010578:Petroleum; D019800:Phenol; D010636:Phenols; D012722:Sewage; D062065:Wastewater; C024836:4-nitrophenol
Activated sludge; Cyanide; Denitrification; Inhibition; Nitrification; Oxygen uptake rate; Phenol