Microbial community dynamics during aerobic granulation in a sequencing batch reactor (SBR)

Abstract

Microorganisms in aerobic granules formed in sequencing batch reactors (SBR) remove contaminants, such as xenobiotics or dyes, from wastewater. The granules, however, are not stable over time, decreasing the removal of the pollutant. A better understanding of the granule formation and the dynamics of the microorganisms involved will help to optimize the removal of contaminants from wastewater in a SBR. Sequencing the 16S rRNA gene and internal transcribed spacer PCR amplicons revealed that during the acclimation phase the relative abundance of Acinetobacter reached 70.8%. At the start of the granulation phase the relative abundance of Agrobacterium reached 35.9% and that of Dipodascus 89.7% during the mature granule phase. Fluffy granules were detected on day 43. The granules with filamentous overgrowth were not stable and they lysed on day 46 resulting in biomass wash-out. It was found that the reactor operation strategy resulted in stable aerobic granules for 46 days. As the reactor operations remained the same from the mature granule phase to the end of the experiment, the disintegration of the granules after day 46 was due to changes in the microbial community structure and not by the reactor operation.

Microbial Ecology of Granular Biofilm Technologies for Wastewater Treatment: A Review

“…This property allows aerobic granules to treat wastewater with diverse toxic substances and pollutants. Some EPS producers are Flavobacterium , Acinetobacter , Thauera , Zoogloea , Devosia , Stenotrophomonas , and Rhodocyclus , among others [ 27 , 30 , 31 , 32 , 33 , 34 ].…”

“…Filamentous bacteria and fungal mycelium have been described as the backbone of aerobic granules due to their ability to increase the surface in which other microorganisms can be adsorbed, accelerating the granulation process [ 17 , 22 , 24 ]. Fungi could be more implied in granule formation when pH is low, whereas, at a higher pH, filamentous bacteria are more involved than fungi [ 32 ]. Some of these filamentous bacteria are members of the Roseiflexus and Chloroflexi genera [ 23 , 39 ].…”

Bacterial Community Structure and Dynamic Changes in Different Functional Areas of a Piggery Wastewater Treatment System

“…At present, the most commonly used biological treatments are the aerobic method, the anaerobic method, and the aerobic-anaerobic mixed method. In aerobic biological treatment, sequencing batch-activated sludge (SBR) is used to treat livestock and poultry wastewater; this process is commonly chosen because of its simplicity, effectiveness in removing COD, NH 3 -N, and phosphorus, good sludge sedimentation performance, and strong adaptability to water quality and quantity changes [2]. The anaerobic method of treating livestock and poultry wastewater uses an upflow anaerobic sludge blanket (UASB) reactor, which has the advantages of high efficiency, low operation costs, and low engineering costs [3].…”