Novel characterisation of biofuel-integrated phytoremediation of liquid wastes with Scenedesmus obliquus

This study investigates the feasibility of in situ phytoremediation of leachate and wastewater in municipal solid waste facilities using microalgae and their valorisation for biofuel production. Laboratory-scale experiments were conducted by cultivating the Scenedesmus obliquus microalga in a diluted growth medium inside a 4 L indoor photobioreactor, operating in batch mode. Volumetric productivity data were employed to evaluate the economic viability of the system. Then, a numerical model developed in Aspen Plus was used to estimate the utility requirements for upgrading crude microalgae oil into biodiesel meeting commercial specifications. The results indicate that, although the resulting biodiesel satisfies UNI EN 14214 quality standards, the limited biomass productivity remains a critical constraint for economic feasibility. Remuneration, in terms of net present value is achievable only under scenarios that combine high biomass yield and microalgae oil sale prices exceeding 2–2.5 € kg−1. The system generates 57–722 k€ after 20 years.