Application of a Tannin-Based Coagulant for Harvesting Parachlorella Kessleri Microalgae Cultivated in Chicken Meat Thermal Processing Wastewater

Microalgae cultivation has been used for treating wastewater from diverse activities. The biomass separation after the treatment is usually a costly step and can be traditionally performed by coagulation and flocculation, followed by sedimentation or flotation. Tannin-based coagulants have emerged as an alternative to inorganic coagulants, which could contaminate biomass with metals. This study aimed to evaluate using a tannin-based coagulant to separate the biomass of Parachlorella kessleri microalgae cultivated in wastewater from chicken meat thermal processing and compare this methodology with the centrifugation method. Jar tests were carried out to evaluate three different tannin-based coagulants. The obtained biomass was then characterized by protein, lipids, suspended solids (total and volatiles), and thermogravimetric analysis (TGA). The Tanfloc MT coagulant reduced the turbidity and apparent color in the wastewater by 99.76% and 80%, respectively. The biomass obtained using the Tanfloc MT presented 39.21% of crude protein, while the biomass obtained by centrifugation had 28.78%. Thermogravimetric analysis revealed a mass loss of 62.2% for the biomass obtained by the centrifugation method and 76.8% for that obtained with the tannin-based coagulant based. Tannin-based coagulant can be considered a potential alternative to separate Parachlorella kessleri microalgae used to treat wastewater from the thermal processing of chicken meat.