<![CDATA[Domestic wastewater contains organic compounds and nitrogen that can degrade water quality if not properly treated. Microalgae-based treatment offers a dual approach as bioremediation and producer of biomass and lipids with bioenergy potential. This study aims to analyze the effect of photoperiod variation on Chlorella vulgaris biomass production, Chemical Oxygen Demand (COD) and ammonia removal, and lipid content in a Rotary Biological Contactor (RBC) using domestic wastewater. The study was conducted at laboratory scale over eight days with three photoperiod variations, FP1 (15:9), FP2 (12:12), and FP3 (9:15) light: dark hours, under batch and semi-continuous systems. Biomass, lipid content, COD, and ammonia were analyzed gravimetrically and spectrophotometrically. Results showed that the highest biomass was obtained under batch FP1 at 1.53 g with the lowest final COD of 63.49 mg/l, the best ammonia removal under FP2 with a final value of 8.6 mg/l, and the highest lipid content of 40.06% under batch FP2. This study demonstrates that photoperiod optimization in a domestic wastewater-based RBC reactor can simultaneously enhance Chlorella vulgaris productivity in both wastewater treatment and bioenergy production. This research provides a scientific contribution related to the optimal photoperiod configuration in the microalgae-based RBC system, which can be a fundamental reference in the development of sustainable domestic waste processing technology integrated with the provision of bioenergy raw materials.]]>
