Optimizing wastewater treatment: Algae-mediated calcite formation and carbon sequestration through bicarbonate control.

The growing emphasis on sustainability in environmental health, climate change, and water usability has driven the exploration of economically and environmentally friendly approaches to enhance wastewater quality. Algae-mediated natural precipitation of minerals in wastewater, driven by these organisms' carbon utilization in photosynthesis, has emerged as a promising wastewater treatment (WWT) method due to its sustainability and cost-efficiency benefits. This study examines the impact of varying carbon content in bicarbonate forms on algae activity in mediating CaCO 3 precipitation and how pH in algae-mediated solutions influences calcite precipitation. Solutions with different Ca²⁺ and HCO 3 ⁻ concentrations were prepared, and algae growth curves were established to ensure solution suitability. The experiments, conducted in two sets, employed ANOVA and t -test analyses for samples with common calcium concentration. Results indicated that increasing HCO3- concentration positively correlates with algae mediation and CaCO 3 precipitation, while elevating pH from 9.8 to 11.0 negatively correlates with calcite precipitation. In conclusion, HCO 3 ⁻ additions were effective in enhancing algae-mediated calcite precipitation in wastewater. Recommendations include ensuring proportionate HCO 3 ⁻ additions to calcium content to optimize mineral precipitation without detrimental effects on algae. [Display omitted] • Need for economic and eco-friendly wastewater treatment. • Utilization of algae for mediating mineral precipitation. • Increasing HCO 3 ⁻ concentration boosts algae mediation and CaCO 3 precipitation. • pH shows an inverse relationship with calcite precipitation. [ABSTRACT FROM AUTHOR]