Treating Synthetic Wastewater Using a Trickling Photobioreactor:

Effects of Light and Hydraulic Retention Time on Organic Matter Removal and Nitrification

Abstract

A trickling photobioreactor (ID 13.5 ㎝, H 30 ㎝, 3 layers) packed with polyester cubes (8㎤, occupancy 47％) was fed with synthetic wastewater (TOC 104 ㎎/L, T-N 50 ㎎/L, PO₄^3－-P 11 ㎎/L）to demonstrate high wa,tewater treatment performance by algal–bacterial consortia at hydraulic retention time (HRT) of 12-2h with red LED irradiation (15 µmol/㎡/s, L:D＝12h/12h). The effluent TOC, T-N, and PO₄^3－-P concentrations at HRT of 12h were4.5 ㎎/L, 29.3 ㎎/L, and 8.1 ㎎/L, respectively, for the photoreactor and 9.1 ㎎/L, 40.5 ㎎/L, and 7.2 ㎎/L for the conventional trickling filter without LED irradiation. The photoreactor with green algae, diatoms, and bacteria had high capabilities for TOC removal, nitrification, and carbon-utilization potential at HRT longer than 8h.