title: Study on the aerobic biodegradability and degradation kinetics of 3-NP; 2,4-DNP and 2,6-DNP.
abstract: Four biodegradability tests (BOD(5)/COD ratio, production of carbon dioxide, relative oxygen uptake rate and relative enzymatic activity) were used to determine the aerobic biodegradability of 3-nitrophenol (3-NP), 2,4-dinitrophenol (2,4-DNP) and 2,6-dinitrophenol (2,6-DNP). Furthermore, biodegradation kinetics of the compounds was investigated in sequencing batch reactors both in the presence of glucose (co-substrate) and with nitrophenol as the sole carbon source. Among the three tested compounds, 3-NP showed the best biodegradability while 2,6-DNP was the most difficult to be biodegraded. The Haldane equation was applied to the kinetic test data of the nitrophenols. The kinetic constants are as follows: the maximum specific degradation rate (K(max)), the saturation constants (K(S)) and the inhibition constants (K(I)) were in the range of 0.005-2.98 mg(mgSS d)(-1), 1.5-51.9 mg L(-1) and 1.8-95.8 mg L(-1), respectively. The presence of glucose enhanced the degradation of the nitrophenols at low glucose concentrations. The degradation of 3-NP was found to be accelerated with the increasing of glucose concentrations from 0 to 660 mg L(-1). At high (1320-2000 mg L(-1)) glucose concentrations, the degradation rate of 3-NP was reduced and the K(max) of 3-NP was even lower than the value obtained in the absence of glucose, suggesting that high concentrations of co-substrate could inhibit 3-NP biodegradation. At 2,4-DNP concentration of 30 mg L(-1), the K(max) of 2,4-DNP with glucose as co-substrate was about 30 times the value with 2,4-DNP as sole substrate. 2,6-DNP preformed high toxicity in the case of sole carbon source degradation and the kinetic data was hardly obtained.
authors.affiliation: Key Laboratory of Marine Environmental Science and Ecology, Ministry of Education, College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China.
authors.forename: Zonglian
authors.initials: Z
authors.lastname: She
authors.forename: Tian
authors.initials: T
authors.lastname: Xie
authors.forename: Yingjie
authors.initials: Y
authors.lastname: Zhu
authors.forename: Leilei
authors.initials: L
authors.lastname: Li
authors.forename: Gaifeng
authors.initials: G
authors.lastname: Tang
authors.forename: Jian
authors.initials: J
authors.lastname: Huang
mesh_terms: D019297:2,4-Dinitrophenol / Q000302:isolation & purification*; D000332:Aerobiosis; D001673:Biodegradation, Environmental; D057919:Biological Oxygen Demand Analysis; D005947:Glucose / Q000737:chemistry; D007700:Kinetics; D008962:Models, Theoretical; D009596:Nitrophenols / Q000302:isolation & purification*; D062065:Wastewater / Q000737:chemistry / Q000382:microbiology; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods*
chemical_list: D019297:2,4-Dinitrophenol; D005947:Glucose; D009596:Nitrophenols; D062065:Wastewater; D014874:Water Pollutants, Chemical; C053026:2,6-dinitrophenol; C049017:3-nitrophenol