Ammonium removal by native microbes and activated sludge within the Jialu River basin and the associated microbial...

To explore the availability of native microbes and activated sludge for ammonium removal, the native microbes and activated sludge in Jialu River basin were investigated in terms of ammonium-removing activities and their microbial communities using spectrophotometry and high-throughput sequencing. NH₄⁺-N and total nitrogen (TN) in the targeted river ranged from 2.45 ± 1.76 to 8.56 ± 2.54 mg/L and from 3.42 ± 2.79 to 13.49 ± 5.06 mg/L, respectively. Both the native microbes and activated sludge had strong ammonium-removing activities with the removal efficiencies of more than 94%. High-throughput sequencing results indicated that, after five batches of operation, the class Gammaproteobacteria (28.55%), Alphaproteobacteria (14.55%), Betaproteobacteria (13.89%), Acidobacteria (8.82%) and Bacilli (7.04%) were dominated in native community, and there was a predominance of Gammaproteobacteria (21.57%), Betaproteobacteria (16.33%), Acidobacteria (12.41%), Alphaproteobacteria (10.01%), Sphingobacteriia (6.92%) and Bacilli (6.66%) in activated sludge. These two microbial sources were able to remove ammonium, while activated sludge was more cost-effective.