Shift in microbial community structure of anaerobic side-stream reactor in response to changes to anaerobic solid retention time and sludge interchange ratio.
A laboratory scale nutrient removal activated sludge system coupled with an anaerobic side-stream reactor was operated for 300 days treating real urban wastewater. A significant decrease in sludge production was obtained increasing the anaerobic solid retention time (SRTASSR) and decreasing the sludge interchange ratio (IR). In this study, the microbial community structure was analyzed and compared with the sludge reduction performance. Quantitative polymerase chain reaction analyses encoding 16 ribosomal RNA and functional genes revealed a wide diversity of phylogenetic groups in each experimental period, resulting from long solids retention time and recirculation of sludge under aerobic, anoxic and anaerobic conditions. However, decreasing SRTASSRfrom 10 to 2.5d and increasing IR from 27 to 100%, an increasing selection of both fermenting bacteria able to release extracellular polymeric substances and hydrolyze organic matter and slow growing bacteria involved in nutrient removal were detected and linked to the sludge reduction mechanisms.
Department of Civil, Environmental and Mechanical Engineering, University of Trento, Trento, Italy. Electronic address: roberta.ferrentino@unitn.it.
Roberta
R
Ferrentino
Department of Civil, Environmental and Mechanical Engineering, University of Trento, Trento, Italy.
Michela
M
Langone
Department of Earth and Environmental Sciences, University of Milano-Bicocca, Milano, Italy.
Isabella
I
Gandolfi
Department of Earth and Environmental Sciences, University of Milano-Bicocca, Milano, Italy.
Valentina
V
Bertolini
Department of Earth and Environmental Sciences, University of Milano-Bicocca, Milano, Italy.
Andrea
A
Franzetti
Department of Civil, Environmental and Mechanical Engineering, University of Trento, Trento, Italy.
Gianni
G
Andreottola
D000693:Anaerobiosis; D001105:Archaea / Q000235:genetics / Q000378:metabolism; D001419:Bacteria / Q000235:genetics / Q000378:metabolism; D019149:Bioreactors / Q000382:microbiology*; D059013:Microbial Consortia / Q000235:genetics / Q000502:physiology*; D010802:Phylogeny; D012722:Sewage / Q000737:chemistry; D014865:Waste Disposal, Fluid / Q000295:instrumentation* / Q000379:methods; D062065:Wastewater
D012722:Sewage; D062065:Wastewater
Anaerobic side-stream reactor; DPAO; Microbial community; SRB; Sludge reduction; Taxonomic identification