Enhancing domestic wastewater treatment through four chlorophyta strains-based phycoremediation: nutrient removal efficiency and algal physiology.

Phycoremediation is a promising solution for environmentally sustainable wastewater treatment. However, its effectiveness depends on the selection of suitable microalgae species. In this study, four algal species (, , , and sp.) were evaluated for their ability to remove pollutants from secondary treated domestic wastewater using multi-soil-layering (MSL) technology. Among the four strains tested, exhibited the highest algal density (2.832 ± 0.187 × 10 cells/mL) and outperformed other species with phosphorus, nitrogen, and COD removal rates exceeding 82.01%, 63.64%, and 61.09% respectively. In addition, had a higher total chlorophyll content of 31.11 µg. L (Chl a: 15.47 ± 0.148 µg. L; Chl b: 15.642 ± 0.052 µg. L) than other species. Physiological analyses of proline and glycine betaine indicated that the two strains experienced lower stress levels, which facilitated an accelerated bioremediation process compared to other Chlorophyta, namely and sp. The efficiency of in the treatment of secondary treated wastewater from MSL, combined with its maximum biomass production, underlines its potential for industrial application. Consequently, there is a compelling interest in evaluating within a prototype as a prelude to industrial development.