Inhibitory effect of the xenobiotic 1,2-dichloroethane in a nitrifying biofilm reactor

2007 ◽  
Vol 55 (8-9) ◽  
pp. 67-73 ◽  
Author(s):  
B. Alpaslan Kocamemi ◽  
F. Çeçen

The aim was to investigate the inhibitory effect of the xenobiotic 1,2-DCA on nitrification during the cometabolic degradation in a packed bed nitrifying biofilm reactor. This xenobiotic inhibited primarily the conversion of NH4-N to hydroxylamine by binding to the AMO enzyme. It had no inhibitory effect on the conversion of nitrite to nitrate. At high NH4-N loadings, the presence of 1,2-DCA inhibited NH4-N utilisation more severely than at low loadings. The suppressing effect of 1,2-DCA on NH4-N utilisation was found to be reversible due to the ability of cells to recover from inhibition. These results could fill a gap in the literature about the potential use of nitrifying biofilm systems for cometabolic treatment of 1,2-DCA and could be useful in the design of engineered 1,2-DCA remediation/treatment in biofilm reactors.

1992 ◽  
Vol 26 (3-4) ◽  
pp. 567-576 ◽  
Author(s):  
F. A. Ruiz-Treviño ◽  
S. González-Martínez ◽  
C. Doria-Serrano ◽  
M. Hernández-Esparza

This paper presents the kinetic analysis, using Generalized Power-Law equations to describe the results of an experimental investigation conducted on a batch submerged biofilm reactor for phosphorus removal under an anaerobic/aerobic cycle. The observed rates and amounts of phosphorus release and organic substrate uptake in the anaerobic phase leads to a kinetic model in which these two variables are dependent on each other with a non-linear behaviour and reach equilibrium values in both cases, at different times and are function of rate constants ratio. The model has a good fit with experimental data except for C uptake at anaerobic contact times longer than four hours, where other kinetics are implied. Kinetic parameters were obtained with different initial substrate concentrations, anaerobic contact cycles, and type of substrates.


1995 ◽  
Vol 31 (1) ◽  
pp. 215-225 ◽  
Author(s):  
Gerald E. Speitel ◽  
Robert L. Segar

Aerobic cometabolism of chlorinated aliphatic solvents in biofilm reactors is a potential treatment technology for contaminated water and air streams. This research investigated cometabolism by pure and mixed cultures of methanotrophs and mixed cultures of phenol-degrading bacteria. Initial experiments with continuous-flow, packed-bed bioreactors proved unsuccessful; therefore, the major focus of the work was on sequencing biofilm reactors, which cycle between two modes of operation, degradation of chlorinated solvents and rejuvenation of the microbial population. Particular success was obtained with a mixed culture of phenol degraders in the treatment of chlorinated ethenes (e.g., trichloroethylene - TCE). Under the best operating conditions, 90% removal of TCE occurred at a 14-minute packed-bed hydraulic residence time. The bioreactors required only two, 1.5 h biomass rejuvenation periods per day to sustain this removal. Experiments with Methylosinus trichosporium OB3b were less successful because of the organism's slow growth rate, relatively poor ability to attach to surfaces, and its inability to successfully compete with other methanotrophs in the bioreactor environment. Overall, however, the research demonstrated the potential attractiveness of sequencing biofilm reactors in treating water contaminated with chlorinated solvents.


Author(s):  
Qianqian Lu ◽  
Nannan Zhang ◽  
Chen Chen ◽  
Miao Zhang ◽  
Dehua Zhao ◽  
...  

Lab-scale simulated biofilm reactors, including aerated reactors disturbed by short-term aeration interruption (AE-D) and non-aerated reactors disturbed by short-term aeration (AN-D), were established to study the stable-state (SS) formation and recovery after disturbance for nitrogen transformation in terms of dissolved oxygen (DO), removal efficiency (RE) of NH4+-N and NO3−-N and activity of key nitrogen-cycle functional genes amoA and nirS (RNA level abundance, per ball). SS formation and recovery of DO were completed in 0.56–7.75 h after transition between aeration (Ae) and aeration stop (As). In terms of pollutant REs, new temporary SS formation required 30.7–52.3 h after Ae and As interruptions, and seven-day Ae/As interruptions required 5.0% to 115.5% longer recovery times compared to one-day interruptions in AE-D and AN-D systems. According to amoA activity, 60.8 h were required in AE-D systems to establish new temporary SS after As interruptions, and RNA amoA copies (copy number/microliter) decreased 88.5%, while 287.2 h were required in AN-D systems, and RNA amoA copies (copy number/microliter) increased 36.4 times. For nirS activity, 75.2–85.8 h were required to establish new SSs after Ae and As interruptions. The results suggested that new temporary SS formation and recovery in terms of DO, pollutant REs and amoA and nirS gene activities could be modelled by logistic functions. It is concluded that temporary SS formation and recovery after Ae and As interruptions occurred at asynchronous rates in terms of DO, pollutant REs and amoA and nirS gene activities. Because of DO fluctuations, the quantitative relationship between gene activity and pollutant RE remains a challenge.


2010 ◽  
Vol 44 (9) ◽  
pp. 2745-2752 ◽  
Author(s):  
Mauro Majone ◽  
Federico Aulenta ◽  
Davide Dionisi ◽  
Ezio N. D'Addario ◽  
Rosa Sbardellati ◽  
...  

1991 ◽  
Vol 23 (7-9) ◽  
pp. 1417-1425 ◽  
Author(s):  
Sheng-Kun Chen ◽  
Chin-Kun Juaw ◽  
Sheng-Shung Cheng

Two sets of fixed-film biological processes were operated separately for nitritification of amnonium and for denitritification of nitrite associated with organic compounds. High strength amnonium wastewater (50-1000 mg NH4+-N/l) could be effectively nitritified by a draft-tube fluidized bed which was operated at an extremely high loading of 1.0 kg NH4−1-N/m3.day with 95% amnonium conversion and 60 to 95% nitrite formation. Additionally, a biofilm fixed-bed was employed to denitritify the high strength nitrite (200 to 1000 mg NO2−-N/l) associated with organic compounds of glucose, acetate and benzoic acid. Complete nitrite removal could be achieved with sufficient HRT and COD/NO2−-N ratio. The conversion ratios were estimated experimentally at 2.5 for glucose and acetate, and 2.0 g ∆COD/g ∆NO2−-N for benzoic acid. A proposed process of an aerobic nitritifying biofilm reactor combined with an anoxic denitritifying biofilm reactor in series could be employed for complete nitrogen removal.


1992 ◽  
Vol 26 (3-4) ◽  
pp. 703-711 ◽  
Author(s):  
B. Rusten ◽  
H. Ødegaard ◽  
A. Lundar

A novel moving bed biofilm reactor has been developed, where the biofilm grows on small, free floating plastic elements with a large surface area and a density slightly less than 1.0 g/cm3. The specific biofilm surface area can be regulated as required, up to a maximum of approximately 400 m2/m3. The ability to remove organic matter from concentrated industrial effluents was tested in an aerobic pilot-plant with two moving bed biofilm reactors in series and a specific biofilm surface area of 276 m2/m3. Treating dairy wastewater, the pilot-plant showed 85% and 60% COD removal at volumetric organic loading rates of 500 g COD/m3h and 900 g COD/m3h respectively. Based on the test results, the moving bed biofilm reactors should be very suitable for treatment of food industry effluents.


2014 ◽  
Vol 49 (3) ◽  
pp. 234-244
Author(s):  
Fang He ◽  
Fusheng Li ◽  
Haihong Zhou ◽  
Lingling Niu ◽  
Liguo Wang

In this research, biocompounds designed out of two polymers having different degradability was investigated for use as the sole carbon source and biofilm carrier to remove perchlorate in particle-fixed biofilm reactors. Both laboratory batch and column experiments were conducted with perchlorate contaminated groundwater. Batch experiments demonstrated clearly that ClO4– was removed from the aqueous phase readily and the degradation rate constants (k) changed in the range of 0.23–0.37 mg/L h as ClO4– concentration increased from 2 to 8 mg/L. Simultaneous perchlorate and nitrate degradation occurred in the polymer bioreactor. Effluent concentrations of perchlorate varied positively with temperature and fitted the Arrhenius equation expression as k=k20•100.0316(t–20) over the range of 13–30 °C. No perchlorate was detected in the effluent of polymer columns after 20 days’ startup. Complete perchlorate removal was observed at a hydraulic loading rate doubled to 1.8 mL/min. Images prove the concept of the pore and filament structure within the biocompounds, which provide both a heterotrophic biofilm and carbon source. Denaturing gradient gel electrophoresis analysis and partial sequencing of 16S rRNA genes indicated that formerly reported perchlorate-reducing bacteria were present in the polymer particle-fixed biofilm reactors.


1989 ◽  
Vol 33 (2) ◽  
pp. 164-172 ◽  
Author(s):  
Christopher T. Skowlund ◽  
Dale W. Kirmse

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