Biomass production of microalgae and scale-up design of high rate algal ponds for citrus industry effluent tertiary treatment, Tucumán, Argentina

Argentina remains one of the main world producers of lemon, being Tucumán the region with longer production in the country. Citrus industries generate thousands of litres of effluents that must be treated before being discharged into the environment. Phycoremediation as a bioremediation strategy enhances the usage of algae and microalgae resources. During the last years, many studies around phycoremediation as a method to treat industrial effluents have been published, but none is applied as a tertiary treatment to adjust the parameters of the water discharged by citrus harvest and industry. Microalgal biomass has several applications be that in the protein nourishment industry or biofuels. Hence this research aims to obtain algae biomass from industrial citrus effluent treatment. This development of this project reconciles the algae variety Scenedesmus acutus to an industrial citrus effluent from the province of Tucumán through Bold's basal medium. Experiments were framed at a laboratory scale with 12:12 hours photoperiod and proportional aeration needed. Effluent treatment and production of 0.83 g/L of biomass took place in 5 L batch bioreactors. Conditions of previous cultural experiences were adopted to obtain constant growth. Citrus effluent treatment removed 96% BOD, 86% COD, and 81% Nitrogen from the composition. The experimental data provided patron extrapolated to a modeled kinetic curve growth. Then a mass balance results in 11 ha “raceway” type bioreactor with a production capacity of 373 kg/day of microalgae biomass from 1500 m3 of wastewater treated. This research reflects the capabilities of citric waste used as raw material to obtain microalgal biomass by Scenedesmus acutus for biofuels application, to preserve the environment through innovative industrial operations. [Display omitted] •The study adapted Scenedesmus acutus to the effluent from citrus industry in Tucumán, as a tertiary treatment.•The citrus effluent treatment by microalgae removed 96% BOD, 86% COD, and 81% Nitrogen.•A modeled kinetic curve growth of the Verlhoust model for growing simulation was performed.•The capacity of the design reactor is 373 kg/day of microalgae biomass from 1500 m3 of wastewater treated.•Plant of HRAP is feasible due to non-cultivable land in the factory.