Shining a light on outdoor algal systems for wastewater treatment: How artificial light enhancement impacts biomass costs and life cycle

ABSTRACT: Microalgae-based wastewater treatment is increasingly viewed as a cleaner production strategy, combining nutrient removal and biomass generation for high-value applications. However, productivity constraints remain a critical barrier to broader implementation. This study examines the viability of integrating light-emitting diodes (LEDs) into outdoor bubble column reactors for domestic wastewater treatment and biomass production, focusing on environmental impacts and techno-economic performance. Three lighting regimes—natural light only (control), 12-h LED cycles, and 24-h LED cycles—were experimentally evaluated and scaled up using Aspen Plus® simulation. Life cycle assessments (LCA) were conducted to quantify environmental impacts (ReCiPe, 2016 method), and a detailed techno-economic analysis determined minimum biomass selling prices. Compared to the control, LED-assisted systems increased biomass yields by 24–34 %, yet capital and operational costs offset productivity gains. Under grid electricity, minimum selling prices considering capital and operational costs ranged from 80.76 to 91.37 USD/kg for LED systems versus 68.85 USD/kg for the control. Photovoltaic (PV) integration reduced operational costs by up to 16.89 %, but LED scenarios remained more expensive. LCA findings highlighted substantially higher environmental impacts (78–149 times) for LED systems, partly alleviated by PV-powered operations. Sensitivity analysis identified nutrient availability, process scale, and reactor costs as pivotal factors influencing the feasibility of LED-enhanced wastewater treatment. Overall, while LED technology offers notable productivity benefits, its economic and environmental trade-offs underscore the need for integrated approaches—ranging from material innovations to policy incentives—to achieve truly sustainable wastewater-based microalgal production.

Keywords

Microalgae Process scale-up challenges Environmental impacts Life cycle assessment Wastewater treatment PV Systems

URI

http://hdl.handle.net/10400.9/6158

Citation

Magalhães, I., Jesus Jr, M., França, B., Silva, T., Pereira, A., Souza, L., Rodrigues, F., Reis, A., Assemany, P., & Calijuri, M.L. (2025). Shining a light on outdoor algal systems for wastewater treatment: How artificial light enhancement impacts biomass costs and life cycle. In: Journal of Environmental Management, 2025, vol. 391, article 126510. https://doi.org/10.1016/j.jenvman.2025.126510