Efficient wastewater treatment and biomass co-production using energy microalgae to fix C, N, and P

Distillery wastewater (DWW), characterized by high organic and nutrient loads, represents a significant environmental challenge, requiring effective and sustainable treatment solutions. This study investigates an innovative approach that integrates microalgae cultivation with DWW treatment for simultaneous bioremediation and biomass production, while also exploring carbon sequestration. We analyzed the growth characteristics, nutrient removal efficiency, protein accumulation, and ultrastructural changes of Chlamydomonas reinhardtii and Scenedesmus dimorphus under varying nitrogen-to-phosphorus (N/P) ratios in diluted DWW. Optimal nutrient removal and biomass accumulation were achieved at N/P concentrations of 46/11.5 mg L^-1. C. reinhardtii showed particularly high nutrient removal rates, with significantly high removal rates for total nitrogen, total phosphorus, and chemical oxygen demand. S. dimorphus, under the same conditions, demonstrated exceptional protein accumulation and also effectively removed pollutants. Both species showed enhanced performance under these conditions, with microalgal cell organelles remaining structurally intact, and chloroplasts and thylakoid layers well-developed. The study also explored carbon sequestration potential using varying CO₂ concentrations, where C. reinhardtii exhibited enhanced biomass accumulation at 3000 ppm CO₂. This integrated approach offers an effective and economically feasible solution for distillery wastewater treatment, simultaneously enabling biomass production and carbon capture. The dual benefits of bioremediation and bioenergy generation position this technology as a promising pathway for sustainable resource management and environmental protection.