Optimizing photoperiods for enhanced microalgae-based phycoremediation of food wastewater in Malaysia

¹ Department of Petrochemical Engineering, Faculty of Engineering and Green Technology, Universiti Tunku Abdul Rahman, Kampar 31900, Perak, Malaysia
² Department of Chemical & Petroleum Engineering, Faculty of Engineering, Technology & Built Environment, UCSI University, Cheras 56000, Kuala Lumpur, Malaysia
³ School of Chemical Engineering, Universiti Sains Malaysia, Nibong Tebal, Penang 14300, Malaysia
⁴ Academician Workstation of Zhai Mingguo, University of Sanya, Sanya 572000, China
⁵ Department of Industrial Engineering, Faculty of Engineering and Green Technology, Universiti Tunku Abdul Rahman, Kampar 31900, Perak, Malaysia

^* Corresponding author: tohpy@utar.edu.my; leongss@utar.edu.my

Abstract

Food processing wastewater poses significant environmental challenges due to high pollutant levels, necessitating effective treatment methods. While Chlorella vulgaris has shown promise in wastewater treatment, the optimal light/dark photoperiod regimes for maximizing biomass growth, nutrient removal efficiency, and COD reduction remain underexplored. This study evaluates the effects of 12H:12H light/dark and 24H light photoperiods on the performance of C.vulgaris in treating food processing wastewater. The 12H:12H photoperiod achieved 73% COD removal with a biomass yield of 0.44 g/L, while the 24H light achieved 75% COD removal with a biomass yield of 1.02 g/L. Both photoperiods fully removed ammonia by day 12. Although the 24H light period increased biomass production, it is energy-intensive, whereas the 12H:12H photoperiod is more energy-efficient but requires further evaluation. These findings highlight the importance of optimizing photoperiod regimes to enhance the efficacy of microalgae-based wastewater treatment. This research supports sustainable wastewater management in the food industry and aims to meet regulatory standards through tailored photoperiod strategies.