Aerobic Treatment of Oily Wastewater: Effect of Aeration and Sludge Concentration to Pollutant Reduction and PHB Accumulation

This study is aimed to investigate feasibility of the aerobic biological process to treat oily wastewater from palm oil food industry. Effect of aeration and sludge concentrations are studied. Raw sludge and raw wastewater was mixed and acclimatized for five days in a stirred tank reactor. The aeration rate (no aeration, low; 1.5L/min and high rate; 2L/min) and sludge concentration (3675, 7350, and 11025mg/L of VSS) were varied. Responses of process were pH, COD, oil and grease, VSS, and PHB content. It was found that the treatment can remove 85.1 to 97.1 % of COD and remove 12.9 to 54.8% of oil & grease. The PHB yield was found to be within 0.15% to 2.4% as PHB/VSS ratio and 0.01% to 0.12% as PHB/COD removed. The higher aeration results a high COD removal and oil & grease removal, while experiment without aeration gives better PHB yield. Higher sludge concentrations (11025mg/L VSS) give higher removal of oil & grease while moderate sludge concentration (7350mg/L VSS) give better result in COD removal. Higher PHB yield is obtained in low sludge concentration (3675mg/L).




References:
[1] S. Lee and J. Yu. Production of biodegradable thermoplastics from
municipal sludge by a two-stage bioprocess. Resour Conserv Recy.,
vol. 19, pp. 151-164, 1997
[2] H. Salehizadeh and M. C. M. Van Loosdrecht, "Production of
polyhydroxyalkanoates by mixed culture: recent trends and
biotechnological importance," Biotechnology Advances, vol. 22, pp.
261-279, 2004.
[3] M. C. M. Van Loosdrecht, J. J. Beun, and J. J. Heijnen, "Poly-[beta]-
hydroxyalkanoate metabolism in activated sludge," in Advances in
Water and Wastewater Treatment Technology, M. Tomonori, H.
Keisuke, T. Satoshi, and S. Hiroyasu, Eds., ed Amsterdam: Elsevier
Science B.V., 2001, pp. 239-248.
[4] S. Y. Lee, K. S. Yim, H. N. Chang, and Y. K. Chang, "Construction of
plasmids, estimation of plasmid stability, and use of stable plasmids for
the production of poly(3-hydroxybutyric acid) by recombinant
Escherichia coli," Journal of Biotechnology, vol. 32, pp. 203-211, 1994.
[5] H. Shimizu, S. Tamura, S. Shioya, and K.-i. Suga, "Kinetic study of
poly-d(-)-3-hydroxybutyric acid (PHB) production and its molecular
weight distribution control in a fed-batch culture of Alcaligenes
eutrophus," Journal of Fermentation and Bioengineering, vol. 76, pp.
465-469, 1993.
[6] A.S.M., Chua, H. Takabatake, H. Satoh, and T. Mino. "Production of
polyhydroxyalkanoates (PHA) by activated sludge treating municipal
wastewater: effect of pH, sludge retention time (SRT), and acetate
concentration in influent," Water Res. 37(15). Pp. 3602-3611.2003.
[7] N. Azbar, (2004). A Review of Waste Management Options in Olive Oil
Production. Crit Rev Env Sci Tech. vol. 34, no. 3, pp 209-247
[8] G. Du and J. Yu, "Metabolic analysis on fatty acid utilization by
Pseudomonas oleovorans: mcl-poly(3-hydroxyalkanoates) synthesis
versus -oxidation," Process Biochemistry vol. 38, pp. 325-332, 2002.
[9] G. Du, J. Chen, J. Yu, and S. Lun, "Continuous production of poly-3-
hydroxybutyrate by Ralstonia eutropha in a two-stage culture system,"
Journal of Biotechnology, vol. 88, pp. 59-65, 2001.
[10] J. Wang and J. Yu, "Kinetic analysis on inhibited growth and poly(3-
hydroxybutyrate) formation of Alcaligenes eutrophus on acetate under
nutrient-rich conditions," Process Biochemistry, vol. 36, pp. 201-207,
2000.
[11] D. Byrom, "Production of poly-[beta]-hydroxybutyrate: poly-[beta]-
hydroxyvalerate copolymers," FEMS Microbiology Letters, vol. 103, pp.
247-250, 1992.
[12] T. Tsuge, K. Tanaka, and A. Ishizaki, "Development of a novel method
for feeding a mixture of L-Lactic Acid and Acetic Acid in Fed Batch
Culture of Ralstonia eutropha," Journal of Bioscience and
Bioengineering, vol. 91, pp. 545-550, 2001.
[13] Y. Poirier, "Production of new polymeric compounds in plants " Current
Opinion in Biotechnology, vol. 10, pp. 181-185, 1999.
[14] P. Kahar, T. Tsugea, K. Taguchi, and Y. Doi, "High yield production of
polyhydroxyalkanoates from soybean oil by Ralstonia eutropha and its
recombinant strain," Polymer Degradation and Stability, vol. 83, pp. 79-
86, 2004.
[15] J. H. Law and R. A. Slepecky, "Assay of Poly-b-hydroxybutyric acid,"
Journal of Bacteriology, vol. 82, pp. 33-36, 1961.
[16] G. Braunegg, G. Lefebvre, and K. F. Genser, "Polyhydroxyalkanoates,
biopolyesters from renewable resources-Physiological and engineering
aspects," Journal of Biotechnology, vol. 65, pp. 127-161, 1998.
[17] E. Y. Lee and C. Y. Choi, "Biosynthesis and Biotechnological
Production of Degradable Polyhydroxyalkanoic Acid," Biotechnol.
Bioprocess Eng, vol. 2, pp. 1-10, 1997.
[18] B. Qu and J. Liu, "Determination of optimum operating conditions for
production of polyhydroxybutyrate by activated sludge submitted to
dyna[1]mic feeding regime," Chinese Science Bulletin, vol. 54, pp. 142-
149, 2009.
[19] G.-C. Du, J. Chen, H.-J. Gao, Y.-G. Chen, and S.-Y. Lun, "Effects of
environmental conditions on cell growth and poly-b-hydroxybutyrate
accumulation in Alcaligenes eutrophus," World Journal of Microbiology
& Biotechnology, vol. 16, pp. 9-13, 2000.
[20] L. S. Serafim, P. C. Lemos, M. G. Albuquerque, and M. A. Reis,
"Strategies for PHA production by mixed cultures and renewable waste
materials," Applied microbiology and biotechnology, vol. 81, pp. 615-
28, Dec 2008.
[21] K. Johnson, R. Kleerebezem, and M. C. van Loosdrecht, "Influence of
the C/N ratio on the performance of polyhydroxybutyrate (PHB)
producing sequencing batch reactors at short SRTs," Water research,
vol. 44, pp. 2141-52, Apr 2010.
[22] S. Shahhosseini, "Simulation and optimisation of PHB production in
fed-batch culture of Ralstonia eutropha," Process Biochemistry, vol. 39,
pp. 963-969, 2004.