Influence of poultry and swine blood shocks on the performance of microalgal heterotrophic bioreactor

Abstract

Slaughterhouse blood is an inevitable part of the meat production chain and represents a problematic by-product due to the high volumes generated, and it is very high pollutant load. When discarded directly into the wastewater treatment facilities, they may cause abrupt variations in effluent concentration compromising the performance of biological wastewater treatment. In this sense, the objective of this work was to assess the performance of heterotrophic microalgal bioreactor in the poultry and swine slaughterhouse wastewater treatment when submitted to organic shock loads. The experiments were performed in a bubble column bioreactor, operating at 25°C, pH of 7.5, 100 mg/L of Phormidium autumnale, aeration of 1 VVM (volume of air per volume of culture per minute), and the absence of light. The organic shock loads were performed with 0.5%, 1%, 3%, 5%, 7%, and 10% of a mixture of poultry and swine blood (50% v/v) in a residence time of 48 h. The kinetic data of cell growth and substrate consumption have been collected and analyzed. The results indicate a pronounced variation in removal efficiency as a function of evaluated pollutant (chemical oxygen demand 95.57%–98.90%; total nitrogen 61.85%–88.23%; total phosphorus 77.82%–90.64%). The numerical indices of process performance, besides framing the wastewater from the point of view of international legislation, demonstrate that the bioreactor support organic shock loads typical to that of the poultry and swine slaughterhouse industry can generate.