Journal articles: 'Granuli aerobici'

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Grgas, Dijana, Tibela Landeka Dragičević, Anita Štrkalj, Andrijana Brozinčević, Adelina Ladavac, Tea Štefanac, and Mirjana Galant. "Aerobni granulirani mulj u obradi otpadnih voda." Hrvatski časopis za prehrambenu tehnologiju, biotehnologiju i nutricionizam 16, no. 1-2 (June 1, 2021): 20–27. http://dx.doi.org/10.31895/hcptbn.16.1-2.3.

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Aerobni granulirani mulj (AGS, engl. Aerobic Granular Sludge) predstavlja obećavajuću tehnologiju u obradi otpadnih voda kućanstva i industrije. Aerobne granule su samoimobilizirane mikrobne nakupine, bez nosača, a karakterizira ih kompaktna gusta struktura, visoko zadržavanje biomase, visoka učinkovitost uklanjanja onečišćenja i svojstvo brzog taloženja. Na formiranje i stabilnost aerobnog granuliranog mulja utječu brojni čimbenici, poput koncentracija otopljenog kisika, vrijeme prozračivanja, vrsta izvora ugljika, sile smicanja, period gladovanja, vrijeme taloženja. Zbog slojevite strukture granule, sa vanjskim aerobnim slojem i anoksičnim i anaerobnim zonama prema središtu granule, moguće je istovremeno uklanjanje C, N i P. AGS tehnologija ima potencijal smanjenja infrastrukture i operativnih troškova pročišćavanja otpadnih voda. Ovaj rad daje pregled najnovijih spoznaja iz literature o mehanizmu granulacije i svojstvima aerobnih granula.

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Etterer, T., and P. A. Wilderer. "Generation and properties of aerobic granular sludge." Water Science and Technology 43, no. 3 (February 1, 2001): 19–26. http://dx.doi.org/10.2166/wst.2001.0114.

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A sequencing batch reactor (SBR) was used to investigate the generation of different granules cultured under aerobic and alternating anaerobic/aerobic conditions. The reactor was fed with synthetic wastewater. A substrate loading rate of 3.6 kg COD/ (m3 day) was applied. Granules of heterotrophic microorganisms were formed. After the first experimental period of 8 weeks the average granule diameter was 3.2 mm. In the second period, alternating anaerobic/aerobic conditions were applied to form granular sludge with an average diameter of 3.0 mm. An isopycnic centrifugation procedure was used to determine the characteristic density of the aerobic granular sludge. The average density of the granular sludge was 1.044 g/ml and 1.048 g/ml, respectively. In free-settling tests the final settling velocity of single aggregates was examined to estimate porosity. Settling velocities up to 2.0 cm/s could be measured. Calculations based on the experimental results showed an average granula porosity of 72% for the first run and 65% average porosity for the second run. This paper indicates the validity of general assumptions in free-settling tests.

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Liu, Lin, Da-Wen Gao, and Hong Liang. "Effect of sludge discharge positions on steady-state aerobic granules in sequencing batch reactor (SBR)." Water Science and Technology 66, no. 8 (October 1, 2012): 1722–27. http://dx.doi.org/10.2166/wst.2012.339.

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We have investigated the effect of sludge discharge location on the steady-state aerobic granules in sequencing batch reactors (SBRs). Two SBRs were operated concurrently with the same sludge retention time using sludge discharge ports at: (a) the reactor bottom in R1; and (b) the reactor middle-lower level in R2. Results indicate that both reactors could maintain sludge granulation and stable operation, but the two different sludge discharge methods resulted in significantly different aerobic granule characteristics. Over 30 days, the chemical oxygen demand (COD) removal of the two reactors was maintained at similar levels (above 96%), and typical bioflocs were not observed. The average aerobic granule size in R2 was twice that in R1, as settling velocity increased in proportion to size increment. Meanwhile, the production yields of polysaccharide and protein content in R2 were always higher than those in R1. However, due to mass transfer limitations and the presence of anaerobes in the aerobic granule cores, larger granules had a tendency to disintegrate in R2. Thus, we conclude that a sludge discharge port situated at the reactor bottom is beneficial for aerobic granule stability, and enhances the potential for long-term aerobic granule SBR operation.

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de Kreuk, M., and L. de Bruin. "Aerobic Granule Reactor Technology." Water Intelligence Online 4 (December 30, 2015): 9781780402901. http://dx.doi.org/10.2166/9781780402901.

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Bathe, S., M. de Kreuk, B. McSwain, and N. Schwarzenbeck. "Aerobic Granular Sludge." Water Intelligence Online 6 (December 30, 2015): 9781780402055. http://dx.doi.org/10.2166/9781780402055.

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Han, Fei, Mengru Zhang, Zhe Liu, Yufei Han, Qian Li, and Weizhi Zhou. "Enhancing robustness of halophilic aerobic granule sludge by granular activated carbon at decreasing temperature." Chemosphere 292 (April 2022): 133507. http://dx.doi.org/10.1016/j.chemosphere.2021.133507.

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Stes, Hannah, Sven Aerts, Michel Caluwé, Thomas Dobbeleers, Sander Wuyts, Filip Kiekens, Jolien D'aes, Piet De Langhe, and Jan Dries. "Formation of aerobic granular sludge and the influence of the pH on sludge characteristics in a SBR fed with brewery/bottling plant wastewater." Water Science and Technology 77, no. 9 (March 23, 2018): 2253–64. http://dx.doi.org/10.2166/wst.2018.132.

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Abstract A laboratory-scale sequencing batch reactor (SBR) was operated for 450 days to assess aerobic granule formation when treating brewery/bottling plant wastewater by consistent application of a feast/famine regime. The experiment was divided into three major periods according to the different operational conditions: (I) no pH control and strong fluctuations in organic loading rate (OLR) (1.18 ± 0.25 kgCOD·(m3·day)−1), (II) pH control and aeration control strategy to reduce OLR fluctuations (1.45 ± 0.65 kgCOD·(m3·day)−1) and (III) no pH control and stable OLR (1.42 ± 0.18 kgCOD·(m3·day)−1). Aerobic granule formation was successful after 80 days and maintained during the subsequent 380 days. The aerobic granular sludge was characterized by SVI5 and SVI30 values below 60 mL.g−1 and dominated by granular, dense structures. An oxygen uptake rate based aeration control strategy insured endogenous respiration at the end of the aerobic phase, resulting in stable SBR operation when the influent composition fluctuated. The quantitative polymerase chain reaction results show no significant enrichment of Accumulibacter or Competibacter during the granulation process. The 16S rRNA sequencing results indicate enrichment of other, possibly important species during aerobic granule formation while treating brewery wastewaters.

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Seid-mohammadi, Abdolmotaleb, Fatemeh Nouri, and Fateme Asadi. "Factors affecting aerobic granule sludge formation in leachate treatment – a systematic review." Reviews on Environmental Health 35, no. 4 (November 18, 2020): 481–92. http://dx.doi.org/10.1515/reveh-2020-0019.

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AbstractThe biological treatment of landfill leachate due to high concentration of Chemical Oxygen Demand (COD), ammonia, and other toxic compounds is so difficult. One of the leachate treatment technology is the sludge biogranulation, that containing the two aerobic and anaerobic process. The aim of this study was conducted for determining the main factors affecting aerobic granule sludge formation in leachate treatment. In this study, all related papers in international databases were evaluated including Google Scholar, Science Direct, and PubMed, Also Open Access Journal Directory from 1990 until 2020 were investigated. The keywords used included Aerobic Granule Sludge (AGS), leachate treatment, Wastewater treatment, Granular Sequential Batch Reactors (GSBR), Formation Extracellular polymeric substance (EPS). Overall, 2,658 articles were retrieved of which 71 were selected after revising the titles and abstracts. Aerobic granulation has been only lately studied and a limited number of studies have been devoted to identification aspects of the process such as the organic source, and other factor affecting on formation granules. Some factors as shear stress, settling time, and the effluent discharge site have direct effect on the efficiency of aerobic granules reactor and other factors such as divalent metal ions, dissolved oxygen concentration, the ratio of height to diameter of the reactor, temperature affecting on the granulation process. If suitable conditions provide, the aerobic granule sludge process can be useful for leachate treatment.

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Barr, Jeremy J., Andrew E. Cook, and Phillip L. Bond. "Granule Formation Mechanisms within an Aerobic Wastewater System for Phosphorus Removal." Applied and Environmental Microbiology 76, no. 22 (September 17, 2010): 7588–97. http://dx.doi.org/10.1128/aem.00864-10.

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ABSTRACT Granular sludge is a novel alternative for the treatment of wastewater and offers numerous operational and economic advantages over conventional floccular-sludge systems. The majority of research on granular sludge has focused on optimization of engineering aspects relating to reactor operation with little emphasis on the fundamental microbiology. In this study, we hypothesize two novel mechanisms for granule formation as observed in three laboratory scale sequencing batch reactors operating for biological phosphorus removal and treating two different types of wastewater. During the initial stages of granulation, two distinct granule types (white and yellow) were distinguished within the mixed microbial population. White granules appeared as compact, smooth, dense aggregates dominated by 97.5% “Candidatus Accumulibacter phosphatis,” and yellow granules appeared as loose, rough, irregular aggregates with a mixed microbial population of 12.3% “Candidatus Accumulibacter phosphatis” and 57.9% “Candidatus Competibacter phosphatis,” among other bacteria. Microscopy showed white granules as homogeneous microbial aggregates and yellow granules as segregated, microcolony-like aggregates, with phylogenetic analysis suggesting that the granule types are likely not a result of strain-associated differences. The microbial community composition and arrangement suggest different formation mechanisms occur for each granule type. White granules are hypothesized to form by outgrowth from a single microcolony into a granule dominated by one bacterial type, while yellow granules are hypothesized to form via multiple microcolony aggregation into a microcolony-segregated granule with a mixed microbial population. Further understanding and application of these mechanisms and the associated microbial ecology may provide conceptual information benefiting start-up procedures for full-scale granular-sludge reactors.

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Juang, Yu-Chuan, Ay Su, Li-Hsing Fang, Duu-Jong Lee, and Juin-Yih Lai. "Fouling with aerobic granule membrane bioreactor." Water Science and Technology 64, no. 9 (November 1, 2011): 1870–75. http://dx.doi.org/10.2166/wst.2011.139.

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Aerobic granulation (AG) and membrane bioreactor (MBR) are two promising, novel environmental biotechnological processes that draw interest of researchers working in the area of biological wastewater treatment. Membrane fouling in the combined aerobic granular membrane bioreactor (AGMBR) process and the conventional MBR process was investigated in this work. The irreversible fouling on hollow-fibre membranes in both reactors were observed with the multiple staining and confocal laser scanning microscope technique. Following physical and chemical washing, the external fouling layers were mostly removed. However, the biofilms built up in the interior surface of membrane remained and contributed to the irreversible fouling resistance. AGMBR retained most cells with granules, thereby reducing their penetration through membrane and thus the chance to form internal fouling layer. The internal biofilm layer was principally composed of live cells embedded in a matrix of proteins and polysaccharides, with that on AGMBR denser and thicker than that on MBR. Prevention of development of internal biofilm is essential to reduce irreversible fouling of AGMBR and MBR membranes.

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Chen, Yu-You, Xiangliang Pan, Jun Li, and Duu-Jong Lee. "Strengthening aerobic granule by salt precipitation." Bioresource Technology 218 (October 2016): 1253–56. http://dx.doi.org/10.1016/j.biortech.2016.06.111.

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Zhang, Xiufang, Yongqiang Liu, Jun Li, Zhuo Wei, Wenyan Duan, and Fangyuan Chen. "Enhancing Effects of Sludge Biochar on Aerobic Granular Sludge for Wastewater Treatment." Processes 10, no. 11 (November 14, 2022): 2385. http://dx.doi.org/10.3390/pr10112385.

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Sludge biochar can be used as bio-carrier to enhance aerobic granular sludge, however, its impact on the formation and especially long-term stability of aerobic granules has not been fully investigated. In this paper, aerobic granular sludge was cultivated in two parallel sequencing batch reactors (SBRs), R1 and R2, with and without sludge biochar addition in the activated sludge inoculum, respectively. The sludge characteristics, wastewater treatment performance, and microbial community structure of granular sludge were examined on a 240-day operation, during which aerobic granular sludge in the two reactors experienced dynamic changes including granule formation, maturation, breakage, filamentous proliferation, and recovery. Aerobic granules in R1 with biochar formed two weeks earlier than that in R2, presenting a larger mean size, and higher settling ability and biomass retention in the granule maturation period. Concurrently, aerobic granules in R1 showed higher denitrification ability with over 80% removal efficiency throughout the whole operation period. During the maturation period, the ratio of food to biomass (F/M) in R1 was below 0.5 gCOD/gVSS d while it ranged between 0.5 and 1.0 gCOD/gVSS d in R2 due to lower biomass retention. The elemental analysis showed more Ca and P accumulation in aerobic granular sludge from R1, with 3% Ca and 2.75% P in sludge from R1 and 0.91% Ca and 0.75% P in sludge from R2, respectively. The microbial community in R1 had higher richness, diversity, excretion of extracellular polymer substances (EPSs) and abundance of denitrifying genera than that in R2, supporting its higher stability and denitrification performance. These results demonstrated that aerobic granular sludge formed by using sludge biochar as a carrier for granulation can speed up granule formation, improve denitrification performance, and enhance the long-term stability of aerobic granules. The findings disclosed the enhancing effects of biochar for wastewater treatment by aerobic granular sludge, suggesting the potential of practical application of biochar in aerobic granular sludge-based reactors.

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Mat Saad, Azlina, Farrah Aini Dahalan, Naimah Ibrahim, Sara Yasina Yusuf, Siti Aqlima Ahmad, and Khalilah Abdul Khalil. "Settling properties of aerobic granular sludge (AGS) and aerobic granular sludge molasses (AGSM)." E3S Web of Conferences 34 (2018): 02022. http://dx.doi.org/10.1051/e3sconf/20183402022.

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Aerobic granulation technology is applied to treat domestic and industrial wastewater. The Aerobic granular sludge (AGS) cultivated has strong properties that appears to be denser and compact in physiological structure compared to the conventional activated sludge. It offers rapid settling for solid:liquid separation in wastewater treatment. Aerobic granules were developed using sequencing batch reactor (SBR) with intermittent aerobic – anaerobic mode with 8 cycles in 24 hr. This study examined the settling velocity performance of cultivated aerobic granular sludge (AGS) and aerobic granular sludge molasses (AGSM). The elemental composition in both AGS and AGSM were determined using X-ray fluorescence (XRF). The results showed that AGSM has higher settling velocity 30.5 m/h compared to AGS.

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Ivanov, V., S. T. L. Tay, Q. S. Liu, X. H. Wang, Z. W. Wang, and J. H. Tay. "Formation and structure of granulated microbial aggregates used in aerobic wastewater treatment." Water Science and Technology 52, no. 7 (October 1, 2005): 13–19. http://dx.doi.org/10.2166/wst.2005.0175.

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Granular microbial aggregates are used in aerobic treatment of wastewater. The granules have diverse microbial community and complex spatial structure. The structural elements are radial sub-aggregates, concentric layers, channels, pores, polysaccharide plugs, and an anaerobic core of lysed cells. Aerobic bacteria, consisting of 69–84% of microbial biomass, were concentrated in a layer to the depth of 550 μm from the surface of the granule. Facultative anaerobic bacteria, consisting of 9–13% of microbial biomass, dominated in a layer at a depth from 550 μm to 850 μm from the surface of the granule. Obligate anaerobic bacteria, consisting of 2% of microbial biomass, dominated in a layer on the depth from 850 μm to 1,000 μm from the surface of the granule. A core of dead and lysed cells was at a depth greater than 1,000 μm from the surface of the granule. The depth of the anaerobic layer correlated with the appearance of polysaccharide plugs in the pores. Enrichment cultures of microorganisms with high cell surface hydrophobicity or self-aggregation ability can be used to facilitate the formation of microbial granules.

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Weber, S. D., W. Ludwig, K. H. Schleifer, and J. Fried. "Microbial Composition and Structure of Aerobic Granular Sewage Biofilms." Applied and Environmental Microbiology 73, no. 19 (August 17, 2007): 6233–40. http://dx.doi.org/10.1128/aem.01002-07.

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ABSTRACT Aerobic activated sludge granules are dense, spherical biofilms which can strongly improve purification efficiency and sludge settling in wastewater treatment processes. In this study, the structure and development of different granule types were analyzed. Biofilm samples originated from lab-scale sequencing batch reactors which were operated with malthouse, brewery, and artificial wastewater. Scanning electron microscopy, light microscopy, and confocal laser scanning microscopy together with fluorescence in situ hybridization (FISH) allowed insights into the structure of these biofilms. Microscopic observation revealed that granules consist of bacteria, extracellular polymeric substances (EPS), protozoa and, in some cases, fungi. The biofilm development, starting from an activated sludge floc up to a mature granule, follows three phases. During phase 1, stalked ciliated protozoa of the subclass Peritrichia, e.g., Epistylis spp., settle on activated sludge flocs and build tree-like colonies. The stalks are subsequently colonized by bacteria. During phase 2, the ciliates become completely overgrown by bacteria and die. Thereby, the cellular remnants of ciliates act like a backbone for granule formation. During phase 3, smooth, compact granules are formed which serve as a new substratum for unstalked ciliate swarmers settling on granule surfaces. These mature granules comprise a dense core zone containing bacterial cells and EPS and a loosely structured fringe zone consisting of either ciliates and bacteria or fungi and bacteria. Since granules can grow to a size of up to several millimeters in diameter, we developed and applied a modified FISH protocol for the study of cryosectioned biofilms. This protocol allows the simultaneous detection of bacteria, ciliates, and fungi in and on granules.

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Gonzalez-Gil, Graciela, and Christof Holliger. "Aerobic Granules: Microbial Landscape and Architecture, Stages, and Practical Implications." Applied and Environmental Microbiology 80, no. 11 (March 21, 2014): 3433–41. http://dx.doi.org/10.1128/aem.00250-14.

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ABSTRACTFor the successful application of aerobic granules in wastewater treatment, granules containing an appropriate microbial assembly able to remove contaminants should be retained and propagated within the reactor. To manipulate and/or optimize this process, a good understanding of the formation and dynamic architecture of the granules is desirable. Models of granules often assume a spherical shape with an outer layer and an inner core, but limited information is available regarding the extent of deviations from such assumptions. We report on new imaging approaches to gain detailed insights into the structural characteristics of aerobic granules. Our approach stained all components of the granule to obtain a high quality contrast in the images; hence limitations due to thresholding in the image analysis were overcome. A three-dimensional reconstruction of the granular structure was obtained that revealed the mesoscopic impression of the cavernlike interior of the structure, showing channels and dead-end paths in detail. In “old” granules, large cavities allowed for the irrigation and growth of dense microbial colonies along the path of the channels. Hence, in some areas, paradoxically higher biomass content was observed in the inner part of the granule compared to the outer part. Microbial clusters “rooting” from the interior of the mature granule structure indicate that granules mainly grow via biomass outgrowth and not by aggregation of small particles. We identify and discuss phenomena contributing to the life cycle of aerobic granules. With our approach, volumetric tetrahedral grids are generated that may be used to validate complex models of granule formation.

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Zhou, Yan Nian, Jun Li, Jing Li, and Su Wei. "Dewaterability of Aerobic Granular Sludge." Applied Mechanics and Materials 90-93 (September 2011): 2944–48. http://dx.doi.org/10.4028/www.scientific.net/amm.90-93.2944.

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Dewatering characteristics of aerobic granular sludge, activated sludge and sludge which mixed flocculant was studied. It was shown that the specific resistance of aerobic granular sludge is lower than activated sludge and sludge with mixed flocculant was in the range of 1.07~1.80×109 S2/g, and it increased with the increase of diameters of the granules. The water ratio of aerobic granular sludge by pressure filtrate dehydration was decreased to 83.5~86.1%, activated sludge and sludge which mixed flocculant were 94.2% and 91.4%, respectively. The structural characteristics, distribution features of extracellular polymeric substances and PN/PS values of aerobic granular sludge were important factors of its excellent dewaterability. Aerobic granular sludge technology was regarded as one of the promising biotechnologies in sludge treatment.

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Williams, J. C., and F. L. de los Reyes. "Microbial community structure of activated sludge during aerobic granulation in an annular gap bioreactor." Water Science and Technology 54, no. 1 (July 1, 2006): 139–46. http://dx.doi.org/10.2166/wst.2006.381.

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A novel annular gap reactor was designed to create a controlled shear environment in which aerobic granular sludge could be developed. The bacterial and eukaryal community structures during two aerobic granular sludge experiments were tracked using denaturing gradient gel electrophoresis (DGGE). The first granule cultivation experiment, using an organic loading rate of 1.6 kg/m3d COD, resulted in biomass that was dominated by filamentous bacteria and Zoogloea ramigera colonies. A second experiment with a higher organic loading rate of 6 kg/m3d COD developed a granule-like morphology but was ultimately dominated by filamentous fungi. Species identification via DGGE band purification and DNA sequencing closely matched the observed sludge morphology and behavior.

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Johnson, Bruce R., and Heather A. Stewart. "Dynamic Aerobic Granular Sludge Modeling." Proceedings of the Water Environment Federation 2018, no. 5 (January 1, 2018): 559–65. http://dx.doi.org/10.2175/193864718824940097.

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Adav, Sunil S., Duu-Jong Lee, Kuan-Yeow Show, and Joo-Hwa Tay. "Aerobic granular sludge: Recent advances." Biotechnology Advances 26, no. 5 (September 2008): 411–23. http://dx.doi.org/10.1016/j.biotechadv.2008.05.002.

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Kwon, Gyutae, Hyun-Gu Kim, and Dae-Hee Ahn. "Effects of Aerobic Granular Sludge Separator on the Stability of Aerobic Granular Sludge (AGS)." Journal of Environmental Science International 30, no. 12 (December 30, 2021): 1081–92. http://dx.doi.org/10.5322/jesi.2021.30.12.1081.

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Campo, Riccardo, Claudio Lubello, Tommaso Lotti, and Gaetano Di Bella. "Aerobic Granular Sludge–Membrane BioReactor (AGS–MBR) as a Novel Configuration for Wastewater Treatment and Fouling Mitigation: A Mini-Review." Membranes 11, no. 4 (April 4, 2021): 261. http://dx.doi.org/10.3390/membranes11040261.

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This mini-review reports the effect of aerobic granular sludge (AGS) on performance and membrane-fouling in combined aerobic granular sludge–membrane bioreactor (AGS–MBR) systems. Membrane-fouling represents a major drawback hampering the wider application of membrane bioreactor (MBR) technology. Fouling can be mitigated by applying aerobic granular sludge technology, a novel kind of biofilm technology characterized by high settleability, strong microbial structure, high resilience to toxic/recalcitrant compounds of industrial wastewater, and the possibility to simultaneously remove organic matter and nutrients. Different schemes can be foreseen for the AGS–MBR process. However, an updated literature review reveals that in the AGS–MBR process, granule breakage represents a critical problem in all configurations, which often causes an increase of pore-blocking. Therefore, to date, the objective of research in this sector has been to develop a stable AGS–MBR through multiple operational strategies, including the cultivation of AGS directly in an AGS–MBR reactor, the occurrence of an anaerobic-feast/aerobic-famine regime in continuous-flow reactors, maintenance of average granule dimensions far from critical values, and proper management of AGS scouring, which has been recently recognized as a crucial factor in membrane-fouling mitigation.

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Zhou, Yan, HuiJuan Xu, and Yu Liu. "Molecular mechanisms governing aerobic granular sludge processes." Water Practice and Technology 10, no. 2 (June 1, 2015): 277–81. http://dx.doi.org/10.2166/wpt.2015.032.

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The aerobic granular sludge process is a promising technology for wastewater treatment. The formation and structure of aerobic granules are traditionally thought to depend highly on selection pressures, while the underlying molecular mechanisms are unclear. It is well known that bacteria coordinate their behavior using small signaling molecules, known as quorum sensing (QS). This paper is an attempt to provide updated information on QS mechanisms governing granular sludge processes. It is shown that QS-mediated cellular communication has a significant role throughout aerobic granulation, including granule development, structural stability and integrity maintenance. Such understanding is helpful for developing novel aerobic granular sludge processes.

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Inizan, M., A. Freval, J. Cigana, and J. Meinhold. "Aerobic granulation in a sequencing batch reactor (SBR) for industrial wastewater treatment." Water Science and Technology 52, no. 10-11 (November 1, 2005): 335–43. http://dx.doi.org/10.2166/wst.2005.0710.

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Aerobic granulation seems to be an a attractive process for COD removal from industrial wastewater, characterised by a high content of soluble organic compounds. In order to evaluate the practical aspects of the process, comparative experimental tests are performed on synthetic and on industrial wastewater, originating from pharmaceutical industry. Two pilot plants are operated as sequencing batch bubble columns. Focus was put on the feasibility of the process for high COD removal and on its operational procedure. For both wastewaters, a rapid formation of aerobic granules is observed along with a high COD removal rate. Granule characteristics are quite similar with respect to the two types of wastewater. It seems that filamentous bacteria are part of the granule structure and that phosphorus precipitation can play an important role in granule formation. For both wastewaters similar removal performances for dissolved biodegradable COD are observed (> 95%). However, a relatively high concentration of suspended solids in the outlet deteriorates the performance with regard to total COD removal. Biomass detachment seems to play a non-negligible role in the current set-up. After a stable operational phase the variation of the pharmaceutical wastewater caused a destabilisation and loss of the granules, despite the control for balanced nutrient supply. The first results with real industrial wastewater demonstrate the feasibility of this innovative process. However, special attention has to be paid to the critical aspects such as granule stability as well as the economic competitiveness, which both will need further investigation and evaluation.

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de Kreuk, M. K., N. Kishida, and M. C. M. van Loosdrecht. "Aerobic granular sludge – state of the art." Water Science and Technology 55, no. 8-9 (April 1, 2007): 75–81. http://dx.doi.org/10.2166/wst.2007.244.

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In September 2006, preliminary to the IWA biofilm conference, a second workshop about aerobic granular sludge was held in Delft, The Netherlands, of which a summary of the discussion outcomes is given in this paper. The definition of aerobic granular sludge was discussed and complemented with a few additional demands. Further topics were formation and morphology of aerobic granular sludge, modelling and use of the aerobic granular sludge in practice.

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Long, Bei, Chang-zhu Yang, Wen-hong Pu, Jia-kuan Yang, Fu-biao Liu, Li Zhang, Jing Zhang, and Kai Cheng. "Tolerance to organic loading rate by aerobic granular sludge in a cyclic aerobic granular reactor." Bioresource Technology 182 (April 2015): 314–22. http://dx.doi.org/10.1016/j.biortech.2015.02.029.

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Kagawa, Y., J. Tahata, N. Kishida, S. Matsumoto, C. Picioreanu, M. C. M. van Loosdrecht, and S. Tsuneda. "Modeling the nutrient removal process in aerobic granular sludge system by coupling the reactor- and granule-scale models." Biotechnology and Bioengineering 112, no. 1 (September 2, 2014): 53–64. http://dx.doi.org/10.1002/bit.25331.

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Nor-Anuar, A., Z. Ujang, M. C. M. van Loosdrecht, M. K. de Kreuk, and G. Olsson. "Strength characteristics of aerobic granular sludge." Water Science and Technology 65, no. 2 (January 1, 2012): 309–16. http://dx.doi.org/10.2166/wst.2012.837.

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Aerobic granular sludge has a number of advantages over conventional activated sludge flocs, such as cohesive and strong matrix, fast settling characteristic, high biomass retention and ability to withstand high organic loadings, all aspects leading towards a compact reactor system. Still there are very few studies on the strength of aerobic granules. A procedure that has been used previously for anaerobic granular sludge strength analysis was adapted and used in this study. A new coefficient was introduced, called a stability coefficient (S), to quantify the strength of the aerobic granules. Indicators were also developed based on the strength analysis results, in order to categorize aerobic granules into three levels of strength, i.e. very strong (very stable), strong (stable) and not strong (not stable). The results indicated that aerobic granules grown on acetate were stronger (high density: >150 g T SSL−1 and low S value: 5%) than granules developed on sewage as influent. A lower value of S indicates a higher stability of the granules.

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Gómez-Basurto, Fabiola, Miguel Vital-Jácome, Elizabeth Selene Gómez-Acata, Frederic Thalasso, Marco Luna-Guido, and Luc Dendooven. "Microbial community dynamics during aerobic granulation in a sequencing batch reactor (SBR)." PeerJ 7 (August 29, 2019): e7152. http://dx.doi.org/10.7717/peerj.7152.

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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.

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Tay, S. T. L., H. L. Jiang, and J. H. Tay. "Functional analysis of microbial community in phenol-degrading aerobic granules cultivated in SBR." Water Science and Technology 50, no. 10 (November 1, 2004): 229–34. http://dx.doi.org/10.2166/wst.2004.0651.

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Phenol-degrading aerobic granules were cultivated in a sequencing batch reactor with an influent phenol concentration of 500 mg l−1. Eight strains were isolated from aerobic granules to characterize the functional redundancy of the microbial community in the granules. The specific oxygen utilization kinetics show the eight strains possessed different phenol-degrading activities, with half-saturation constants (Ks) ranging from 0.4 to 70.5 mg phenol l−1. Two isolates belonging to dominant populations expressed differing functions. The first strain was linked to the function of phenol degradation as this strain has the highest phenol-degrading ability among all isolates, while the second strain was linked to the maintenance of the granule structure because of its strong self-flocculation activity. This study could be used to exploit the granule-based system for treating high-strength wastewaters.

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Liu, Jianrong, David Nguyen, and Michael Paice. "Aerobic granule formation in a sequencing batch reactor treating newsprint effluent under low phosphate conditions." Water Science and Technology 62, no. 11 (December 1, 2010): 2571–78. http://dx.doi.org/10.2166/wst.2010.943.

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Pulp and paper mills are under increasing pressure to minimize the discharge of phosphate to receiving waters. We investigated the operation of two laboratory sequencing batch reactors (SBR) under low phosphate conditions over a period of eight months. Performance characteristics in terms of COD and TSS removal were similar to the full-scale mill activated sludge operation, but the floc density and structure was improved. Sludge yield as a result of phosphate limitation was routinely lower than 0.15 kg/kg of COD. Aerobic granule formation was established in one of the SBRs by reducing the settling time from 30 min to 2 min and by increasing stirring shear force. Once established, the brown granules which were 1–2 mm in diameter were stable over five months of operation. Extracellular polymeric substance (EPS) analysis of the granules indicated a higher galactose content and lower mannose content than in conventional flocs. The granules generated more quorum sensing compound (acyl homoserine lactone) than conventional flocs, suggesting that quorum sensing could play a role in granule formation. When compared to the conventional SBR, the aerobic granule SBR performed at a higher organic loading, at faster settling velocity, and without filamentous bulking.

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Li, Yong, and Yu Liu. "Diffusion of substrate and oxygen in aerobic granule." Biochemical Engineering Journal 27, no. 1 (December 2005): 45–52. http://dx.doi.org/10.1016/j.bej.2005.06.012.

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Yan, Ailan, Dongqin He, Jinte Zou, Shuyun Wu, and Jun Li. "Dewatering performance of aerobic granular sludge." DESALINATION AND WATER TREATMENT 194 (2020): 93–100. http://dx.doi.org/10.5004/dwt.2020.25812.

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34

Nor Anuar, A., Z. Ujang, M. C. M. van Loosdrecht, and M. K. de Kreuk. "Settling behaviour of aerobic granular sludge." Water Science and Technology 56, no. 7 (October 1, 2007): 55–63. http://dx.doi.org/10.2166/wst.2007.671.

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Aerobic granular sludge (AGS) technology has been extensively studied recently to improve sludge settling and behaviour in activated sludge systems. The main advantage is that aerobic granular sludge (AGS) can settle very fast in a reactor or clarifier because AGS is compact and has strong structure. It also has good settleability and a high capacity for biomass retention. Several experimental works have been conducted in this study to observe the settling behaviours of AGS. The study thus has two aims: (1) to compare the settling profile of AGS with other sludge flocs and (2) to observe the influence of mechanical mixing and design of the reactor to the settleability of AGS. The first experimental outcome shows that AGS settles after less than 5 min in a depth of 0.4 m compared to other sludge flocs (from sequencing batch reactor, conventional activated sludge and extended aeration) which takes more than 30 min. This study also shows that the turbulence from the mixing mechanism and shear in the reactor provides an insignificant effect on the AGS settling velocity.

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Dangcong, Peng, Nicolas Bernet, Jean-Philippe Delgenes, and Rene Moletta. "Aerobic granular sludge—a case report." Water Research 33, no. 3 (February 1999): 890–93. http://dx.doi.org/10.1016/s0043-1354(98)00443-6.

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36

Zhang, Quanguo, Jianjun Hu, and Duu-Jong Lee. "Aerobic granular processes: Current research trends." Bioresource Technology 210 (June 2016): 74–80. http://dx.doi.org/10.1016/j.biortech.2016.01.098.

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Khan, Mohammad Zain, Farah Khan, and Suhail Sabir. "Aerobic granular treatment of 2,4-dichlorophenol." Canadian Journal of Chemical Engineering 89, no. 4 (February 9, 2011): 914–20. http://dx.doi.org/10.1002/cjce.20445.

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Berg, Lenno, Catherine M. Kirkland, Joseph D. Seymour, Sarah L. Codd, Mark C. M. Loosdrecht, and Merle K. Kreuk. "Heterogeneous diffusion in aerobic granular sludge." Biotechnology and Bioengineering 117, no. 12 (August 6, 2020): 3809–19. http://dx.doi.org/10.1002/bit.27522.

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Cydzik-Kwiatkowska, Agnieszka, Paulina Rusanowska, and Katarzyna Głowacka. "Operation mode and external carbon dose as determining factors in elemental composition and morphology of aerobic granules." Archives of Environmental Protection 42, no. 1 (March 1, 2016): 74–79. http://dx.doi.org/10.1515/aep-2016-0009.

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Abstract The elemental composition and morphology of aerobic granules in sequencing batch reactors (GSBRs) treating high-nitrogen digester supernatant was investigated. The investigation particularly focused on the effect of the number of anoxic phases (one vs. two) in the cycle and the dose of external organics loading (450 mg COD/(L·cycle) vs. 540 mg COD/(L·cycle)) on granule characteristics. Granules in all reactors were formed of many single cells of rod and spherical bacteria. Addition of the second anoxic phase in the GSBR cycle resulted in enhanced settling properties of the granules of about 10.6% and at the same time decreased granule diameter of about 19.4%. The study showed that external organics loading was the deciding factor in the elemental composition of biomass. At 540 mg COD/(L·cycle) the granules contained more weight% of C, S and N, suggesting more volatile material in the granule structure. At lower organics loadings granules had the higher diameter of granules which limited the diffusion of oxygen and favored precipitation of mineral compounds in the granule interior. In this biomass higher content of Mg, P and Ca, was observed.

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Sturm, B. S. McSwain, and R. L. Irvine. "Dissolved oxygen as a key parameter to aerobic granule formation." Water Science and Technology 58, no. 4 (September 1, 2008): 781–87. http://dx.doi.org/10.2166/wst.2008.393.

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Much research has asserted that high shear forces are necessary for the formation of aerobic granular sludge in Sequencing Batch Reactors (SBRs). In order to distinguish the role of shear and dissolved oxygen on granule formation, two separate experiments were conducted with three bench-scale SBRs. In the first experiment, an SBR was operated with five sequentially decreasing superficial upflow gas velocities ranging from 1.2 to 0.4 cm s−1. When less than 1 cm s−1 shear was applied to the reactor, aerobic granules disintegrated into flocs, with corresponding increases in SVI and effluent suspended solids. However, the dissolved oxygen also decreased from 8 mg L−1 to 5 mg L−1, affecting the Feast/Famine regime in the SBR and the substrate removal kinetics. A second experiment operated two SBRs with an identical shear force of 1.2 cm s−1, but two dissolved oxygen concentrations. Even when supplied a high shear force, aerobic granules could not form at a dissolved oxygen less than 5 mg L−1, with a Static Fill. These results indicate that the substrate removal kinetics and dissolved oxygen are more significant to granule formation than shear force.

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Etchebehere, C., M. I. Errazquin, A. Cabezas, M. J. Pianzzola, M. Mallo, P. Lombardi, G. Ottonello, L. Borzacconi, and L. Muxí. "Sludge bed development in denitrifying reactors using different inocula-performance and microbiological aspects." Water Science and Technology 45, no. 10 (May 1, 2002): 365–70. http://dx.doi.org/10.2166/wst.2002.0370.

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Aerobic and methanogenic consortia were evaluated as inocula for laboratory scale denitrifying reactors, fed with a synthetic wastewater with acetate as the main electron donor. The denitrifying microflora of inocula and reactors was evaluated by specific denitrifying activity, enumeration and isolation of denitrifiers, which were screened by amplified ribosomal DNA restriction analysis. Reactor performance was monitored by COD and nitrate removal efficiencies and granule size. The aerobic sludge failed to form granules, probably due to the development of a filamentous, nitrate-reducing organism which was characterised by 16SrDNA sequencing as Bacillus cereus. The methanogenic sludge showed denitrifying activity and adapted very rapidly to denitrifying conditions in the two reactors seeded with granules of different sizes. Denitrifiers grew around the granules, increasing the specific denitrifying activity of the sludge over 10-fold. Exopolymer-forming organisms, belonging to the same species, were isolated from both reactors. Granule size increased during operation, but flotation of the aggregates, related to gas retention was observed.

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McSwain, B. S., R. L. Irvine, and P. A. Wilderer. "The effect of intermittent feeding on aerobic granule structure." Water Science and Technology 49, no. 11-12 (June 1, 2004): 19–25. http://dx.doi.org/10.2166/wst.2004.0794.

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Self-immobilized biofilms, or aerobic granules without the addition of carrier material, have only been reported in one suspended growth system, the Sequencing Batch Reactor (SBR) with a very short fill time (dump fill). The SBR utilizes intermittent feeding which creates a period of high load followed by starvation (often referred to as feast-famine). In this experiment, three identical SBRs were operated with different feeding conditions to determine the role of feast-famine on granule formation. All three SBRs were operated with a total volumetric load of 2.4 kg/m3·d. The 90 minute Fill phase was altered for each reactor, providing an increasing time of Aerated Fill. A dump fill condition was applied for one reactor, while the other two reactors were aerated for different times during Fill, resulting in a smaller COD load at the beginning of each React phase. Aerobic granules formed in all reactors, but the structural properties and content of filamentous organisms were clearly dependent on a high feast condition. Only the reactor with dump fill formed compact, stable granules. It is concluded that intermittent feeding associated with the SBR affects the selection and growth of filamentous organisms and has a critical role in granule structure and composition.

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Dong, Chun Juan, Qing Ye Pan, and Yan Xia Wang. "Thiocyanate Removal from Coking Wastewater through Granular Sludge." Advanced Materials Research 955-959 (June 2014): 2370–73. http://dx.doi.org/10.4028/www.scientific.net/amr.955-959.2370.

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To investigate the removal of thiocyanate () in the actual coking wastewater through granular bio-film reactor, two lab-scale granular bio-film reactors (EGSB reactor) (RA and RB) were continuously operated at three stages for about 16 months: anaerobic vs. micro-aerobic for EGSB reactor, varied influent concentrations and varied shock-loading (abrupt and gradual shock-loading) for micro-aerobic EGSB reactor. Compared with anaerobic operation condition, micro-aerobic operation conditions could distinctly strengthen average removal in the EGSB reactor treating actual coking wastewater (47.8% vs.5.3%). At micro-aerobic operation conditions (only with 2000-5000ml·min-1 air flow rate in the external aeration column), with 12h HRT and varied influent concentrations of 200-540mg·L-1, the EGSB reactor could always keep very high removal of 87.6%-94.1%. Microaerobic EGSB reactor had very strong ability of supporting load shock. During the whole operation stage of continuous loads shock (for about 60 days)(from 0.32kgSCN·m-3·d-1 to 1.08 kgSCN·m-3·d-1), removal ability showed a constantly increasing tendency. Micro-aerobic EGSB reactor was a simple and high effectively treatment strategy for the in the actual coking wastewater, and meanwhile high COD, ammonia, phenol and cyanide removal was also kept in the micro-aerobic EGSB reactor.

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Yang, H. G., J. Li, J. Liu, L. B. Ding, T. Chen, G. X. Huang, and J. Y. Shen. "A case for aerobic sludge granulation: from pilot to full scale." Journal of Water Reuse and Desalination 6, no. 1 (September 2, 2015): 188–94. http://dx.doi.org/10.2166/wrd.2015.188.

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A pilot-scale sequencing batch reactor (SBR) treating 120 m3/d of a town's wastewater was set up in 2009 and aerobic granules with a mean diameter of 0.28 mm, mixed liquor suspended solids (MLSS) of 7,500 mg/L and sludge volume index (SVI)30 of 43 mL/g were achieved. A full-scale SBR with 50,000 m3/d for treating a town's wastewater was operated in 2010 and aerobic granules with a mean MLSS of 2,285 mg/L and SVI30 of 52.5 mL/g were obtained. Aerobic granules had excellent performances of chemical oxygen demand (COD) and NH4+-N removal and remained stable for a long time. Raw wastewater and SBR operating mode had a positive effect on aerobic granule formation. Therefore, aerobic granular technology could be successfully applied in the full-scale bioreactor under specific conditions. Future development of aerobic granular technology is the application in full-scale continuous-flow reactors.

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Kirkland, Catherine M., Julia R. Krug, Frank J. Vergeldt, Lenno van den Berg, Aldrik H. Velders, Joseph D. Seymour, Sarah L. Codd, Henk Van As, and Merle K. de Kreuk. "Characterizing the structure of aerobic granular sludge using ultra-high field magnetic resonance." Water Science and Technology 82, no. 4 (July 27, 2020): 627–39. http://dx.doi.org/10.2166/wst.2020.341.

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Abstract Despite aerobic granular sludge wastewater treatment plants operating around the world, our understanding of internal granule structure and its relation to treatment efficiency remains limited. This can be attributed in part to the drawbacks of time-consuming, labor-intensive, and invasive microscopy protocols which effectively restrict samples sizes and may introduce artefacts. Time-domain nuclear magnetic resonance (NMR) allows non-invasive measurements which describe internal structural features of opaque, complex materials like biofilms. NMR was used to image aerobic granules collected from five full-scale wastewater treatment plants in the Netherlands and United States, as well as laboratory granules and control beads. T1 and T2 relaxation-weighted images reveal heterogeneous structures that include high- and low-density biofilm regions, water-like voids, and solid-like inclusions. Channels larger than approximately 50 μm and connected to the bulk fluid were not visible. Both cluster and ring-like structures were observed with each granule source having a characteristic structural type. These structures, and their NMR relaxation behavior, were stable over several months of storage. These observations reveal the complex structures within aerobic granules from a range of sources and highlight the need for non-invasive characterization methods like NMR to be applied in the ongoing effort to correlate structure and function.

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Zhou, Jun, Hongyu Wang, Kai Yang, Fang Ma, and Bin Lv. "Optimization of operation conditions for preventing sludge bulking and enhancing the stability of aerobic granular sludge in sequencing batch reactors." Water Science and Technology 70, no. 9 (September 24, 2014): 1519–25. http://dx.doi.org/10.2166/wst.2014.406.

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Sludge bulking caused by loss of stability is a major problem in aerobic granular sludge systems. This study investigated the feasibility of preventing sludge bulking and enhancing the stability of aerobic granular sludge in a sequencing batch reactor by optimizing operation conditions. Five operation parameters have been studied with the aim to understand their impact on sludge bulking. Increasing dissolved oxygen (DO) by raising aeration rates contributed to granule stability due to the competition advantage of non-filamentous bacteria and permeation of oxygen at high DO concentration. The ratio of polysaccharides to proteins was observed to increase as the hydraulic shear force increased. When provided with high/low organic loading rate (OLR) alternately, large and fluffy granules disintegrated, while denser round-shape granules formed. An increase of biomass concentration followed a decrease at the beginning, and stability of granules was improved. This indicated that aerobic granular sludge had the resistance of OLR. Synthetic wastewater combined highly and slowly biodegradable substrates, creating a high gradient, which inhibited the growth of filamentous bacteria and prevented granular sludge bulking. A lower chemical oxygen demand/N favored the hydrophobicity of granular sludge, which promoted with granule stability because of the lower diffusion rate of ammonia. The influence of temperature indicated a relatively low temperature was more suitable.

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Miksch, Korneliusz, and Kończak Beata. "Distribution of Extracellular Polymeric Substances and their Role in Aerobic Granule Formation." Chemical and Process Engineering 33, no. 4 (December 1, 2012): 679–88. http://dx.doi.org/10.2478/v10176-012-0057-3.

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This study investigated the quantity and distribution of extracellular polymeric substances (EPS) in aerobic granules. Results showed that EPS play an important role in the formation and stabilisation of granules. The content of EPS significantly increases during the first weeks of biogranulation. An analysis of EPS in the granules revealed that the protein level was 5 times higher than in polysaccharides. The increase of protein content correlated with the growth of cell hydrophobicity (r2 = 0.95). EPS and hydrophobicity are important factors in cell adhesion and formation of granules. The aim of this work was also to determine the distribution of EPS in the granule structure. In situ EPS staining showed that EPS are located mostly in the center of granules and in the subsurface layer. The major components of the EPE matrix are proteins, nucleic acids and β-polysaccharides. These observations confirm the chemical extraction data and indicate that granule formation and stability are dependent on protein content.

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Zaghloul, Mohamed S., Asmaa M. Halbas, Rania A. Hamza, and Elsayed Elbeshbishy. "Digestibility of Aerobic Granular Sludge: A Mini Review." Processes 11, no. 2 (January 19, 2023): 326. http://dx.doi.org/10.3390/pr11020326.

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Full-scale wastewater treatment plants utilizing aerobic granular sludge technology are being built in many countries worldwide. As with all biological wastewater treatment plants, the produced waste biomass must be stabilized to protect the population, wildlife, and the environment. Digestion is usually used to break down the complex organics in the waste sludge; however, the digestibility of aerobic granular sludge still needs to be fully understood compared to the conventional activated sludge. This paper reviews the studies published on the digestibility of waste aerobic granular sludge to date. Studies comparing aerobic granular sludge and activated sludge in terms of composition, properties, and digestibility are highlighted. The impact of biological composition and physical properties on the digestibility of sludge is reviewed in terms of biomethane production and biodegradability. The effect of pre-treatment is also covered. Areas for future research are presented.

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Adav, Sunil S., Duu-Jong Lee, and Joo-Hwa Tay. "Extracellular polymeric substances and structural stability of aerobic granule." Water Research 42, no. 6-7 (March 2008): 1644–50. http://dx.doi.org/10.1016/j.watres.2007.10.013.

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Wang, Zhi-Wu, Yong Li, and Yu Liu. "Mechanism of calcium accumulation in acetate-fed aerobic granule." Applied Microbiology and Biotechnology 74, no. 2 (February 2007): 467–73. http://dx.doi.org/10.1007/s00253-006-0540-1.

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Journal articles on the topic 'Granuli aerobici'

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