Circular bioeconomy approach for pig farming systems using microalgae-based wastewater treatment processes

[Display omitted] •It emphasizes the vital role of CBE in promoting sustainable pig farming.•A CBE approach provides both economic and environmental benefits for pig farming.•The CBE outcomes are evaluated with Scenarios (1 to 3).•Scenario 2 using partial microalgae-based biomass recycle is superior to other Scenarios.•Scenario 2 increases revenue and lowers environmental impact, ideal for CBE. The circular bioeconomy (CBE) presents a sustainable solution for the pig farming system, delivering economic and environmental benefits. This shift from a linear to a CBE model is anticipated to result in substantial economic, environmental, and social transformations. In this study, the CBE outcomes are evaluated with Scenarios (1 to 3): (1) pig farming and anaerobic digestion (AD) only, (2) pig farming, AD, and microalgae system (MS) with partial microalgae-based biomass (MB) recycle, and (3) pig farming, AD, and MS without MB recycle. Through economic and life cycle analyses, the internal rate of return for Scenarios (1 to 3) are 13.3%, 15.0%, and 12.3%, respectively, but the corresponding endpoint indicators are 483pt, 363pt, and 398pt. To address the best CBE, Scenario 2 by using MB product as a pig feed supplement could achieve higher revenue as well as lower environmental impact.