Microbiota composition and activity at different stages of the HIAS sewage phosphorus removal

Abstract

Phosphorus contamination from unprocessed sewage causes environmental damages through eutrophication in aqueous ecosystems. Certain biological wastewater treatment plants can remove phosphorus from the wastewater and recycle it for use in agriculture. Enhanced biological phosphorus removal methods employ phosphorus accumulating microbes in biofilms to remove phosphorus from sewage. Hias wastewater treatment plant’s Hias process has shown efficient phosphorus removal and recycling, however, the microbiological function of the process is not well understood. The main aim of this study is to analyze the microbial composition on the biofilm carrying the phosphorus accumulating organisms and changes to the microbiota through the Hias process. To investigate the process, biofilm samples were taken from anaerobic reactor 3, and aerobic reactors 5 and 10. DNA and RNA is extracted using a MagMAX 96 total RNA isolation kit. The nucleic acid content of the samples was sequenced using Illumina. The sequencing showed phosphorus accumulating organism genera Tetrasphaera and Candidatus Accumulibacter in high abundance. The nitrifying and ammonium oxidizing bacteria genera of Nitrosomonas was present at high abundance. The most abundant genera in the data set is Uncultured Saccharibacter. The experimental procedure yielded low concentrations of nucleic acid. This led to statistical uncertainties which made potential biological inferences regarding the microbial community uncertain. This paper then goes into potential improvements on efficiency of the experimental protocol, with regards to nucleic acid extraction from the biofilm. Further work is needed to properly assess the correlations between RNA levels in different reactors.