Evaluation of nutrient removal performance and resource recovery potential of anaerobic/anoxic/aerobic membrane bioreactor with limited aeration

This study proposes a novel strategy to obtain high-efficiency synchronous removal of nitrogen and phosphorus from wastewater by the limited-aeration anaerobic/anoxic/aerobic membrane bioreactor (AAO-MBR) and evaluates its resource recovery potential. Effects of membrane flux on pollutants removal and membrane fouling were investigated, and the optimal flux of 30 L/(m(2).h) was obtained with efficient nitrogen and phosphorus removal of 81.5 +/- 6.1% and 96.7 +/- 2.1%. Compared with traditional and chemical-aided AAO-MBRs, limited aeration AAO-MBR also alleviated membrane fouling by enlarging sludge flocs, improved sludge activities, and enriched the functional bacteria and genes. The sludge denitrification activity and phosphorus uptake activity of the limited-aeration AAO-MBR were 1.7 and 4.2 times as those of the traditional AAO-MBR. Low-temperature sludge pyrolysis results showed that sludge from limited-aeration AAO-MBR had higher nutrient storage and release capacity. This study proved the efficient nutrient removal capacity and high resource recovery potential of the limited-aeration AAO-MBR process.

Automated summary

The limited-aeration AAO-MBR process proposed in this study demonstrated high efficiency in nutrient removal and alleviation of membrane fouling by enhancing sludge floc size, improving sludge activity, and enriching functional bacteria and genes.