Bio-carrier and operating temperature effect on ammonia removal from secondary wastewater effluents using moving bed biofilm reactor (MBBR)

Abstract

This study investigates the impact of bio-carriers' surface area and shape, wastewater chemistry and operating temperature on ammonia removal from real wastewater effluents using Moving bed biofilm reactors (MBBRs) operated with three different AnoxKaldness bio-carriers (K_3, K_5, and M). The study concludes the surface area loading rate, specific surface area, and shape of bio-carrier affect ammonia removal under real conditions. MBBR kinetics and sensitivity for temperature changes were affected by bio-carrier type. High surface area bio-carriers resulted in low ammonia removal and bio-carrier clogging. Significant ammonia removals of 1.420 ± 0.06 and 1.103 ± 0.06 g - N/m². d were achieved by K₃(A_s = 500 m²/m³) at 35 and 20 °C, respectively. Lower removals were obtained by high surface area bio-carrier K₅ (1.123 ± 0.06 and 0.920 ± 0.06 g - N/m². d) and M (0.456 ± 0.05 and 0.295 ± 0.05 g - N/m². d) at 35 and 20 °C, respectively. Theta model successfully represents ammonia removal kinetics with θ values of 1.12, 1.06 and 1.13 for bio-carrier K₃, K₅ and M respectively. MBBR technology is a feasible choice for treatment of real wastewater effluents containing high ammonia concentrations.

Keywords: Biofilm growth; Clogging; Nitrification; Organic loading; Performance; Secondary effluents; Total nitrogen.