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Biodegradation of Phenol from Saline Wastewater Using Moving Bed Biofilm Reactor

Nakhli, Ali Akbar | 2013

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 44057 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Borghei, Mahdi
  7. Abstract:
  8. Many industries such as olive oil mills, petroleum refineries, petrochemical plants and oil field operations generate saline wastewaters containing phenol. The aerobic moving bed biofilm reactor (MBBR) was investigated in this work in order to assess its performance for the degradation and chemical oxygen demand (COD) removal of phenol as the sole substrate from saline wastewater. The effect of inlet concentration of phenol (200–1200mg/L), hydraulic retention time (8–24 h), inlet concentration of salt (10-70gr/L), organic shock loading, hydraulic shock loading and salt shock loading were evaluated on the performance of two 10-liter MBBR seeded with mixed culture of active biomass acclimatized to phenol and salt. The results showed that the investigated reactor could remove more than 99% of phenol and COD from the feed saline wastewater at inlet phenol concentrations up to 800mg/L, HRT 24h and inlet salt concentration 30gr/L. Reducing HRT down to 18h has no significant effect on phenol and COD removal. Increasing salt content in the influent has detrimental effects on microbial activities and the mean efficiencies stayed around 99% for both COD and phenol at inlet salt concentrations up to 40gr/L. Data analysis indicates that the Kincannon-Stover model is a more applicable model than empirical Kargi model for describing the organic removal in moving bed biofilm reactors. The MBBR was very stable against the organic, hydraulic and salt shocks and reactor reached the steady state condition quickly. In the continuous condition suspended biomass (100-400mg/L) was negligible in comparison to the attached biomass on the media (1.405-4.45gr/L). Thickness of the biofilm (52-172.43µm) was in the range of active biofilm thickness during the operation. Microscopic examination showed that there was a large numbers of yeast in the biofilm. Some bacteria and mold were also found in biofilm. While there were only bacteria in the mixed liquor. Overall, the results of this work revealed that establishing a mixed culture of active biomass acclimatized to phenol and salt in the MBBR system can achieve complete degradation of high concentrations of phenol in saline wastewater. This makes it a very efficient and flexible technology for treating such waste streams in full-scale applications
  9. Keywords:
  10. Phenol ; Biological Treatment ; Moving Bed Biofilm Reactor (MBBR) ; Saline Wastewater

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