The effect of operational variables (HRT and AT) on reactor performance and microbial diversity in laboratory-scale aerobic/anoxic up flow bioreactor


avatar Ali Almasi 1 , * , avatar Mohammad Reza Zolfaghari 2 , avatar Zahra Bahman 2 , avatar Ali Akbar Zinatizadeh 3

Dept. of Eenvironmental Engineering, School of Public Health, Kermanshah University of Medical Sciences, Kermanshah, Iran
Dept. of Microbiology, Islamic Azad University, Qom, Iran
Dept. of Chemical Engineering, Razi University, Kermanshah, Iran

how to cite: Almasi A, Zolfaghari M R, Bahman Z, Zinatizadeh A A. The effect of operational variables (HRT and AT) on reactor performance and microbial diversity in laboratory-scale aerobic/anoxic up flow bioreactor. J Kermanshah Univ Med Sci. 2013;17(4):e77098.


Background: Domination of microbial population is an effective parameter of biological process in the bioreactors. The aim of this study was to identify a domain microbial habitat in a sequential aerobic/anoxic bioreactor for the treatment of industrial waste water.
Methods: This study is an experimental one in which the degradation of organic matters was evaluated using laboratory scale aerobic/anoxic up flow bioreactor (UFBR) with an alternatively aeration action in sequence. Bacteriological study was carried out, such as a cultural-based technique, differentiation tests and biomass assessment procedure, detecting domain bacteria in the aerobic/anoxic conditions.
Results: The aerobic/anoxic treatment process resulted in the 45-95% BOD and 75-95% COD removal. The identified bacteries were studied as biological mass. The formed mass were found over than 109CFU/g of the flock forming in sludge built up, the majority of enumerated bacteria were facultative and anaerobic bacteria such as coli forms, micrococcaceae, Staphylococcus and Streptococci and Clostridium perfringens. The small portion of the defined population, less than 10% was detected as aerobic genera such as nitrifyers.
Conclusion: Anoxic condition affects the aerobic bacteria population in such a way that after aeration switching off they don’t have bioreactor in their structure. In opposite facultative and anaerobic bacteria were able flourish in building existence biomass inside the bioreactor. The benefits of this integrated bioreactor are the optimum efficiency which is coincided with no problem of the sludge build up.



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