Single-Stage Biofilm-Based Total Nitrogen Removal in a Membrane Aerated Biofilm Reactor: Impact of Aeration Mode, HRT and Scouring Intensity

Abstract

High energy costs, organic carbon availability, and space limitation are some of the barriers faced by wastewater treatment processes. This research investigates the impact of membrane aeration mode, scouring intensity, and loading rate in a single-stage total nitrogen removal process in a membrane aerated biofilm reactor (MABR). Under ammonia loading of 2.7 g N/m2.d, continuous process aeration led to 1.7 g NH4-N/m2.d and 0.8 g TN/m2.d removal, respectively. Conversely, intermittent (5/12 min on/off) aeration resulted in 35% less ammonia removal but 34% higher total nitrogen (TN) removal. The MABR under ammonia load of 1.6 g N/m2.d showed an enhanced effluent quality with an average of 2.5 mg/L effluent ammonia concentration. This finding highlights the nitrification potential of a flow-through MABR as a standalone treatment step without any downstream process. Also, slough-off, a common issue in the biofilm process and was hypothesized to reduce the removal efficiency, showed increased ammonia removal rates by 20%. The microbial analysis indicated the dominant AOB and NOB species as Nitrosomonas spp. and Nitrospira spp, respectively. Moreover, the relative abundance of denitrifying bacteria (40.5%) were found twice in intermittently-aerated MABR compared to the continuously-aerated one (20.5%). However, NOB and denitrifying bacteria relative abundances were comparable where continuous air was supplied.

Membrane Surface Woven Nylon Fillers Enhance Carbon and Nitrogen Removal of Membrane-Aerated Biofilm Reactor

“…Current studies have demonstrated significant variation in pollutant removal capacities among MABRs, a characteristic largely contingent on the performance of their membrane materials. − The membrane stands as the central element in MABR, serving as both the medium for oxygen transfer and the platform for the immobilization and growth of the biofilm. Membrane materials used for MABR are categorized as microporous, composite, and dense membranes, of which microporous membranes are easy to assemble with low manufacturing costs. ,, However, the limited oxygen transfer, pore-clogging, and biofilm detachment issues make microporous membranes less suitable for large-scale applications.…”