Effect of Organic Load on the Performance and Methane Production of an AnSBBR Treating Effluent from Biodiesel Production

• Published in: Applied biochemistry and biotechnology 2011-09, Vol.165 (1), p.347-368
• Main Authors: Bezerra, Roberto Antonio, Rodrigues, José Alberto Domingues, Ratusznei, Suzana Maria, Canto, Catarina Simone Andrade, Zaiat, Marcelo
• Format: Article
• Language: English
• Subjects: Alkalinity; Biochemistry; Biodiesel fuels; Biofilms; Biofuel production; Biofuels; Biological and medical sciences; Bioreactors; Biotechnology; Chemistry; Chemistry and Materials Science; Effluent treatment; Effluents; Energy; Fundamental and applied biological sciences. Psychology; Hydrogen-Ion Concentration; Industrial applications and implications. Economical aspects; Methane; Methane - metabolism; Organic Chemicals - metabolism; Organic loading; Organic matter; Reactors; Volatile acids; Wastewater treatment; Water treatment
• ISSN: 0273-2289; 1559-0291
• DOI: 10.1007/s12010-011-9255-6

Currently, there is an increasing demand for the production of biodiesel and, consequently, there will be an increasing need to treat wastewaters resulting from the production process of this biofuel. The main objective of this work was, therefore, to investigate the effect of applied volumetric organic load (AVOL) on the efficiency, stability, and methane production of an anaerobic sequencing batch biofilm reactor applied to the treatment of effluent from biodiesel production. As inert support, polyurethane foam cubes were used in the reactor and mixing was accomplished by recirculating the liquid phase. Increase in AVOL resulted in a drop in organic matter removal efficiency and increase in total volatile acids in the effluent. AVOLs of 1.5, 3.0, 4.5 and 6.0 g COD L −1  day −1 resulted in removal efficiencies of 92%, 81%, 67%, and 50%, for effluent filtered samples, and 91%, 80%, 63%, and 47%, for non-filtered samples, respectively, whereas total volatile acids concentrations in the effluent amounted to 42, 145, 386 and 729 mg HAc L −1 , respectively. Moreover, on increasing AVOL from 1.5 to 4.5 g COD L −1  day −1 methane production increased from 29.5 to 55.5 N mL CH 4  g COD −1 . However, this production dropped to 36.0 N mL CH 4  g COD −1 when AVOL was increased to 6.0 g COD L −1  day −1 , likely due to the higher concentration of volatile acids in the reactor. Despite the higher concentration of volatile acids at the highest AVOL, alkalinity supplementation to the influent, in the form of sodium bicarbonate, at a ratio of 0.5–1.3 g NaHCO 3  g COD fed −1 , was sufficient to maintain the pH near neutral and guarantee process stability during reactor operation.