Wastewater Influent Microbial Immigration and Contribution to Resource Consumption in Activated Sludge Using Taxon-Specific Mass-Flow Immigration Model

Abstract

Wastewater influent microorganisms are part of the total chemical oxygen demand (COD) and affect the activated sludge (AS) microbial community. Precise modeling of AS processes requires accurate quantification of influent microorganisms, which is missing in many AS models (ASMs). In this study, influent microorganisms in COD unit were determined using a fast quantification method based on DNA yield and was compared with conventional respirometry method. The actively growing influent microorganisms were identified. A mass-flow immigration model was developed to quantify the influent-to-AS immigration efficiency (mi) of specific taxon i using mass balance and 16S rRNA gene high-throughput sequencing data. The modelled average m was 0.121-0.257 in site 1 (LaPrairie), and 0.050-0.126 in site 2 (Pincourt), which were corrected to 0.111-0.186 and 0.048-0.109 respectively using a constrain of mi [≤] 1. The model was further developed to calculate contributions to organic substrate consumption by specific taxa. Those genera with zero or negative net growth rates were not completely immigration dependent (mi View larger version (30K): org.highwire.dtl.DTLVardef@1d6b43forg.highwire.dtl.DTLVardef@d3b7eborg.highwire.dtl.DTLVardef@1cfaef5org.highwire.dtl.DTLVardef@1e75bdb_HPS_FORMAT_FIGEXP M_FIG C_FIG