Work

Optimization of hydrodynamics for enhanced co-cultivation in bubble column reactors: Investigating flow dynamics and biomass productivity

Year: 2025

Type: article

Abstract: Although hydrodynamic effects on algal cultivation have been studied, limited work has addressed how bubble column diameter influences the co-cultivation of microalgae and duckweed in sewage wastewater systems and biofuel production. Additionally, studies of co-cultivation have never been investigated. This is the first empirical study that fills the gap by experimentally evaluating the co-cultivation of Scenedesmus sp. and Lemna sp. (Duckweed) in wastewater fed bubble column reactors of different diameters (5 cm, 10 cm, and 15 cm), focusing on hydrodynamics, nutrient distribution, fluid flow patterns, and biomass productivity, as well as how co-cultivation supports novel cultivation and attached harvesting methods. The optimal configuration (10 cm diameter) achieved a specific growth rate of 0.74/day and biomass productivity of 93,85 mg/L/day, nearly doubling yields compared to monoculture. Additionally, co-culturing Scenedesmus sp. with Duckweed led to an 11 % increase in growth rates and an almost 90 % boost in biomass productivity, demonstrating multiple benefits, including enhanced nutrient uptake, improved gas exchange, higher photosynthetic efficiency, sustainable bioremediation, and increased lipid and protein content. Results showed that co-cultivation enhanced nutrient uptake, stabilized dissolved oxygen and pH, and improved harvesting efficiency through attached cultivation. These findings demonstrate that optimizing hydrodynamics together with co-cultivation strategies offers a scalable, sustainable pathway for biofuel production and wastewater remediation. Furthermore, this research provides valuable insights into reactor design, contributing to the advancement of large-scale cultivation of microalgae for sustainable bioenergy production.

Source: Results in Engineering

DOI: 10.1016/j.rineng.2025.107841

Authors: Nikita Singh, Prof Manimagalay Chetty, Prof Sudesh Rathilal

Institutions: Durban University of Technology, Cape Peninsula University of Technology

Language: English

Topic: Algal biology and biofuel production

Subfield: Renewable Energy, Sustainability and the Environment

Field: Energy

Domain: Physical Sciences

SDGs: Affordable and clean energy, Clean water and sanitation

Open Access status: gold

Estimated APC paid: $1,940