Aerobic Sludge Granulation in a Full-Scale Sequencing Batch Reactor

Abstract

Aerobic granulation of activated sludge was successfully achieved in a full-scale sequencing batch reactor (SBR) with 50,000 m3 d−1 for treating a town's wastewater. After operation for 337 days, in this full-scale SBR, aerobic granules with an average SVI30 of 47.1 mL g−1, diameter of 0.5 mm, and settling velocity of 42 m h−1 were obtained. Compared to an anaerobic/oxic plug flow (A/O) reactor and an oxidation ditch (OD) being operated in this wastewater treatment plant, the sludge from full-scale SBR has more compact structure and excellent settling ability. Denaturing gradient gel electrophoresis (DGGE) analysis indicated that Flavobacterium sp., uncultured beta proteobacterium, uncultured Aquabacterium sp., and uncultured Leptothrix sp. were just dominant in SBR, whereas uncultured bacteroidetes were only found in A/O and OD. Three kinds of sludge had a high content of protein in extracellular polymeric substances (EPS). X-ray fluorescence (XRF) analysis revealed that metal ions and some inorganics from raw wastewater precipitated in sludge acted as core to enhance granulation. Raw wastewater characteristics had a positive effect on the granule formation, but the SBR mode operating with periodic feast-famine, shorter settling time, and no return sludge pump played a crucial role in aerobic sludge granulation.

Analysis of bacterial, fungal and archaeal populations from a municipal wastewater treatment plant developing an innovative aerobic granular sludge process

“…The MLSS, SVI 30 and granules diameter were observed to be within the ranges of 2.7-4 g/L, 40-56 mL/g and 0.5-0.6 mm, respectively. This is similar to the values previously reported at this WWTP: SVI 30 47.1 mL/g, diameter 0.5 mm, and settling velocity of 42 m/h (Li et al 2014). Granules were observed to have a well-defined elliptical shape ( Fig.…”

“…4a1), which may be due to their affinity for salty and anaerobic conditions. The influent wastewater contains high concentrations of salts (Li et al 2014) and the anaerobic environment of the granules would provide the ideal ecosystem for Planctomycetes. Planctomycetes, Proteobacteria, Acinetobacter and Flavobacterium detection in the AGS, suggested that in addition to producing extracellular polymeric substances favoring granulation they also contributed to the degradation of organic compounds (Adav et al 2008;Jungles et al 2011).…”

“…The average BOD/COD value of influent wastewater was 0.23, which is indicative of the biorefractory nature of wastewater. It is worth noting that raw wastewater contained a large amount of salt in the WWTP (Li et al 2014). …”

“…However, microbial populations of matured AGS have not been analyzed (Lee et al 2010), possible due to a lack of modern analytical approaches. Initial studies of AGS have been conducted in laboratory-scale reactors (de Kreuk 2006;Ni et al 2009;Liu et al 2011;Rocktaschel et al 2015) and very little information is known about AGS collected from full-scale operational WWTP (Giesen et al 2013;Li et al 2014).…”

Chiral Analysis of Pesticides and Drugs of Environmental Concern: Biodegradation and Enantiomeric Fraction

“…Conversion of lab-scale operating reactors to full-scale reactors applied to real scenarios has been accomplished, and Portugal, the Netherlands, South Africa, and China have full-scale batch reactors currently in operation [98]. Advances in this type of technology will benefit the diffusion of its application in the future [99].…”