Scientia Agricola (Dec 2014)

Treatment of cattle-slaughterhouse wastewater and the reuse of sludge for biodiesel production by microalgal heterotrophic bioreactors

  • Mariana Manzoni Maroneze,
  • Juliano Smanioto Barin,
  • Cristiano Ragagnin de Menezes,
  • Maria Isabel Queiroz,
  • Leila Queiroz Zepka,
  • Eduardo Jacob-Lopes

DOI
https://doi.org/10.1590/0103-9016-2014-0092
Journal volume & issue
Vol. 71, no. 6
pp. 521 – 524

Abstract

Read online

Microalgal heterotrophic bioreactors are a potential technological development that can convert organic matter, nitrogen and phosphorus of wastewaters into a biomass suitable for energy production. The aim of this work was to evaluate the performance of microalgal heterotrophic bioreactors in the secondary treatment of cattle-slaughterhouse wastewater and the reuse of microalgal sludge for biodiesel production. The experiments were performed in a bubble column bioreactor using the microalgae Phormidium sp. Heterotrophic microalgal bioreactors removed 90 % of the chemical oxygen demand, 57 % of total nitrogen and 52 % of total phosphorus. Substantial microalgal sludge is produced in the process (substrate yield coefficient of 0.43 mg sludge mg chemical oxygen demand−¹), resulting in a biomass with high potential for producing biodiesel (ester content of more than 99 %, cetane number of 55, iodine value of 73.5 g iodine 100 g−¹, unsaturation degree of ~75 % and a cold filter plugging point of 5 ºC).

Keywords