Microalgae-Based Wastewater Treatment Coupled with Biofuel Production: Techno-Economic Assessment

Anna Kowalski; David Nguyen

doi:10.55001/ijeer.v1i2.62

Abstract

Integrating microalgae cultivation with municipal wastewater treatment enables simultaneous nutrient removal, CO₂ fixation, and biofuel feedstock production, but commercial viability depends on cultivation system design and downstream processing costs. We conduct a comprehensive techno-economic assessment (TEA) of high-rate algal pond (HRAP) and photobioreactor (PBR) systems treating 10 MLD of secondary effluent at four climate zones, coupled with hydrothermal liquefaction (HTL) for biocrude production. The HRAP-HTL pathway achieves wastewater treatment costs of $0.18/m³ (vs. $0.32/m³ for conventional activated sludge) while producing 42 tonnes/year of biocrude per MLD treated. PBR systems yield 2.8× higher biomass productivity but require 3.5× capital investment. Sensitivity analysis identifies biomass productivity, biocrude yield, and carbon credit pricing ($50-80/tonne CO₂) as the dominant parameters affecting net present value (NPV), with breakeven achieved at $72/tonne CO₂ credit price for HRAP systems in subtropical climates.

Author Biographies

Anna Kowalski Faculty of Environmental Engineering, Warsaw University of Technology, 00-661 Warsaw, Poland

Anna Kowalski is a senior researcher at Faculty of Environmental Engineering, Warsaw University of Technology, 00-661 Warsaw, Poland. Their research focuses on data analytics, with over 66 publications in peer-reviewed journals.
David Nguyen School of Chemical and Biomolecular Engineering, University of Sydney, Sydney NSW 2006, Australia

David Nguyen is an assistant professor at School of Chemical and Biomolecular Engineering, University of Sydney, Sydney NSW 2006, Australia. Their research focuses on computational science, with over 26 publications in peer-reviewed journals.