Utilization of native Chlorella strain in laboratory-scale raceway reactor for synthetic wastewater treatment: A study in batch and continuous modes with multi-substrate modeling
Serena Lima, Alessandro Cosenza, Giuseppe Caputo, F. Grisafi, Francesca Scargiali
Abstract
Despite of the possibility to include microalgae in civil wastewater treatment process , the practice is still not common due to the lack of available instruments to implement it. In this study, a straightforward comprehensive approach for dealing with microalgal wastewater treatment involving an original kinetic model is proposed. A first set of batch cultures of a native strain of Chlorella was firstly carried out to obtain the kinetic parameters: maximum growth factor (μ max ) and half-saturation constant (K s ), for each limiting nutrient. Maximum growth factor values of 0.0279 for PO 4 3− , 0.0319 h −1 for NH 4 + , 0.0352 h −1 for glucose, and 0.0263 h −1 for the overall medium were found. Regarding the K s, values of 1.08 mg L −1 , 27.70 mg L −1 , 1.34 mg L −1 , were found for PO 4 3− , NH 4 + and glucose respectively, and a value of 2.8 % of the total nutrients for the overall medium. These parameters were used to set a multi-substrate kinetic model able to predict the growth in batch and in continuous operation within a laboratory scale raceway reactor. The removal capabilities of the microalgae for each addressed pollutant were evaluated in a batch system and in a continuous system at dilution rates of 0.0025, 0.005, 0.01 and 0.015 h −1 . This comprehensive approach represents a significant step towards addressing the continuous treatment of wastewater utilizing microalgae.