Aerobic biodegradation of phenol by activated sludge in a batch reactor

Petronela Cozma1, Raluca-Maria Hlihor1, Laura Carmen Apostol1,2, Mariana Diaconu1, Manuela Olga Pogacean1,3, Maria Gavrilescu1,4

1 Gheorghe Asachi Technical University of Iasi, Faculty of Chemical Engineering and Environmental Protection, Department of Environmental Engineering and Management, 73 Prof. Dr. Docent D. Mangeron, 700050 Iasi, Romania
2 Stefan cel Mare University of Suceava, Romania, Faculty of Food Engineering, 13 Universitatii, 720229 Suceava, Rom nia
3 Plant Protection Agency Mures, 80 Dezrobirii Street, T rgu Mures, Romania
4 Academy of Romanian Scientists, 54 Splaiul Independentei, RO-050094 Bucharest, Romania


The aim of present work is to study the potential of activated sludge sampled from the wastewater treatment plant of Iasi city, Romania, for phenol biodegradation from aqueous solutions under aerobic conditions in a batch reactor. The effects of various factors involved in phenol biodegradation by activated sludge were investigated. The experimental results revealed that the biodegradation of activated sludge is highly affected by the factors mentioned above. Thus, the removal of phenol increases with increasing the pH of solution, reaching a maximum of 99 % at pH 7, for 100 mg/L initial phenol concentration and 25 oC. The ability of activated sludge to degrade phenol is optimized at 30 oC where the biodegradation reaches 100%. The exposure to low temperatures (10 oC) diminishes the activity of microbial community from the activated sludge. Although phenol concentrations up to 100 mg/L are significantly reduced, higher phenol concentrations (up 400 mg/L) are inhibitory for growth, thus reducing the removal efficiency. Functional groups present on the cell surface of activated sludge and involved in the biodegradation of phenol were identified by Fourier transform infrared (FTIR) spectroscopy.


activated sludge; biodegradation; bioreactor; kinetics; phenol

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