چكيده لاتين :
Background and Objective: Exposure to propylene glycol can lead to many health risks on blood, skin and
kidney. Biodegradation of synthetic wastewater containing propylene glycol was studied in a continuous
conventional activated sludge bench scale reactor. Optimum conditions of microorganismsʹ growth for
biodegradation of propylene glycol were determined by Taguchi method.
Materials and Methods: Primary microorganisms for start up of the bioreactor were obtained from sludge
return line of a municipal wastewater treatment plant and adapted to different concentrations of propylene
glycol in a conventional activated sludge reactor. Optimum growth conditions of microorganisms and also
operational conditions of the system including pH, influent COD, source of nitrogen and salinity were
determined in three levels by Taguchi method.
Results: COD removal efficiency in conventional activated sludge reactor for influent concentrations of 400,
700, 900, 1100 and 1300 mg/L were 980/0, 95%, 950/0, 900/0 and 850/0 respectively. Optimization of the
process by Taguchi method showed that source of nitrogen urea, pH = 8, salinity of 80/0 and influent COD of
1300 mg/L with importance priority of 41 %, 250/0, 17.11% and 16.1420/0 were as optimum growth conditions
of microorganisms and also. operational conditions of the system for propylene glycol biodegradation
respectively.
Conclusion: According to the results obtained from this work, it can be concluded that optimum conditions
of biological processes and improvement the efficiency of bioreactors can simply be done by the use of such
experimental designs.
