EFFECT OF PHOTOPERIOD ON THE REMOVAL OF ORGANIC AND NITROGEN USING MICROALGAL-BACTERIAL IN MEMBRANE BIOREACTOR WITHOUT EXTERNAL AERATION

Abstract

This research aims to study the effect of photoperiod on the efficiency of removing organic matter (Chemical Oxygen Demand; COD) and nitrogen (Total Dissolved Nitrogen; TDN) to improve the removal of organic matter and nitrogen, as well as reduce energy use and membrane fouling. The study used one lighted membrane bioreactor without external aeration under stable conditions, with a hydraulic retention time (HRT) of 2 days. Four light-dark patterns: P1 (12:12), P2 (6:6:6:6), P3 (8:4:8:4), and P4 (10:2:10:2). The results showed that between P1 and P2, P2 had removal efficiencies of 96.6±0.3% for organic matter and 95.9±1.0% for nitrogen. This indicates that intermittent lighting with 6 hours of light followed by 6 hours of dark is suitable for removing organic matter and nitrogen and when comparing the lighting duration among P2, P3, and P4, it was found that P3 had the highest efficiency in removing organic matter, at 98.4±1.2%. Next was P4 and P2, with efficiencies of 98.0±4.6% and 96.3±0.3%, respectively. Meanwhile, P2 had the highest nitrogen removal efficiency, at 90.9±2.1%, followed by P4 and P3, with efficiencies of 88.9±1.6% and 88.1±1.8%, respectively. The study indicates that increasing the lighting duration does not lead to simultaneous improvements in organic matter and nitrogen treatment efficiency. P3 provides the highest organic matter removal efficiency, while P2 provides the highest nitrogen removal efficiency. In summary, different lighting patterns and durations affect the efficiency of removing organic matter and nitrogen in a non-aerated illuminated membrane bioreactor system.

Keywords: Membrane Bioreactor, Photoperiod, Fouling