Optimization of Microalgae Separation Using Moringa oleifera Seeds and PVC Influence Through Central Composite Rotatable Design

This study explores microalgae separation efficiency using coagulation-flocculation-sedimentation (CFS) with polyvinyl chloride (PVC) and various Moringa oleifera seed (MO) extracts as coagulants. Anaerobically digested domestic wastewater from the Candeia Wastewater Treatment Plant in Bauru, São Paulo, Brazil, was treated in two pilot scale flat panels photobioreactors, R1 and R2, differing in microplastic (MP) concentration at the inlet, and natural coagulant extraction. The Central Composite Rotational Design (CCRD) optimized operational conditions. Coagulant dosage significantly influenced separation efficacy. Response surface methodology (RSM) identified optimal conditions, with aqueous extract of delipidated MO powder (AEDMOP) and MO powder (MOP) demonstrating noteworthy removal efficiencies in R1 and R2, respectively. PBR R2 required lower coagulant dosages for similar efficiencies, indicating the impact of MP. Despite challenges with seed powder dissolution and model accuracy, the study underscores the potential of natural organic coagulants like MO in microalgae separation from wastewater.