This is a Post-print version of the articleAerobic granular sludge represents an interesting approach for simultaneous organic matter
and nitrogen removal in wastewater treatment plants. However, the information about
microbial communities in aerobic granular systems dealing with industrial wastewater like
pig slurry is limited. Herein, bacterial diversity and dynamics were assessed in a pilot scale
plant using aerobic granular sludge for organic matter and nitrogen elimination from swine
slurry during more than 300 days. Results indicated that bacterial composition evolved
throughout the operational period from flocculent activated sludge, used as inoculum, to
mature aerobic granules. Bacterial diversity increased at the beginning of the granulation
process and then declined due to the application of transient organic matter and nitrogen
loads. The operational conditions of the pilot plant and the degree of granulation determined
the microbial community of the aerobic granules. Brachymonas, Zoogloea and Thauera
were attributed with structural function as they are able to produce extracellular polymeric
substances to maintain the granular structure. Nitrogen removal was justified by partial
nitrification (Nitrosomonas) and denitrification (Thauera and Zoogloea), while Comamonas
was identified as the main organic matter oxidizing bacteria. Overall, clear links between
bacterial dynamics and composition with process performance were found and will help to
predict their biological functions in wastewater ecosystems improving the future control of
the processThis work has been financed by FISHPOL (CTQ2014-55021-R) and GRANDSEA (CTM2014-55397-JIN) projects from the Spanish Government and co-funded by FEDER. The authors belong to the Galician Competitive Research Group GRC 2013-032, programme co-funded by FEDER, and CRETUS (AGRUP2015/02)S
