Removal of bacterial and viral indicator organisms in full-scale aerobic granular sludge and conventional activated sludge systems

The paper presents a set of comparative tests to evaluate the inhibitory effect of crystal violet on the respiration rate of microorganisms in conventional activated sludge and aerobic granular sludge. The tests were performed in similar conditions with the only variable of the type of sludge tested. The results emphasized that the aerobic granular sludge is less susceptible to the toxicity induced by crystal violet. The concentration of crystal violet that inhibits by 50% (CE50) the respiration rate of sludge microorganisms was determined to be, for the specific test conditions, 22.39 mg/L for the conventional activated sludge and 33.88 mg/L for the aerobic granular sludge. The paper also assesses the biodegradability potential of crystal violet from aqueous solution, in the presence of sodium acetate as co-substrate in a lab-scale sequential biological reactor with aerobic granular sludge. The experiments showed that most of the crystal violet is being initially absorbed in the matrix of the granules during the first minutes and subsequently is being removed with efficiencies above 95% within a treatment cycle of 8 hours.

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Advancements in the application of aerobic granular biomass technology for sustainable treatment of wastewater

Water Practice & Technology ◽

10.2166/wpt.2013.007 ◽

2013 ◽

Vol 8 (1) ◽

pp. 47-54 ◽

Cited By ~ 59

Author(s):

A. Giesen ◽

L. M. M. de Bruin ◽

R. P. Niermans ◽

H. F. van der Roest

Keyword(s):

Municipal Wastewater ◽

New Technology ◽

Granular Sludge ◽

Full Scale ◽

Aerobic Granular Sludge ◽

Development Effort ◽

Municipal Wastewater Treatment ◽

Granular Biomass ◽

Under Construction ◽

Activated Sludge Systems

Aerobic granular sludge technology can be regarded as the future standard for industrial and municipal wastewater treatment. As a consequence, a growing number of institutes and universities focus their scientific research on this new technology. Recently, after extensive Dutch research and development effort, an aerobic granular biomass technology has become available to the market. Full scale installations for both industrial and municipal applications are already on stream, under construction or in design. The technology is distinguished by the name ‘Nereda®’ and based on the specific characteristics of aerobic granular sludge. It can be considered as the first mature aerobic granular sludge technology applied at full scale. It improves on traditional activated sludge systems by a significantly lower use of energy and chemicals, its compactness and its favorable capital and operational costs.

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Enhanced settling in activated sludge: design and operation considerations

Water Science & Technology ◽

10.2166/wst.2018.287 ◽

2018 ◽

Vol 78 (2) ◽

pp. 247-258 ◽

Cited By ~ 2

Author(s):

Glen T. Daigger ◽

Eric Redmond ◽

Leon Downing

Keyword(s):

Activated Sludge ◽

Quality Criteria ◽

Granular Sludge ◽

Aerobic Granular Sludge ◽

Water Quality Criteria ◽

Subsequent Removal ◽

Solids Concentration ◽

Activated Sludge Processes ◽

Sludge Settleability ◽

Activated Sludge Systems

Abstract Settling of activated sludge particles has long been the key to successfully achieving secondary treatment. While soluble products can be converted to particulate components via microbial reactions in the activated sludge process, it is the subsequent removal of these particulate components that is the key to achieving ultimate water quality criteria. An understanding of the operating parameters for selecting good settling activated sludge particles was first documented in the 1970s and 1980s. An understanding of the growth pressures that can be imposed on filamentous organisms, and the impacts of selector zones in general, allowed the design and operation of activated sludge processes to routinely achieve good sludge settleability. More recently, research has identified what could be the next evolution in flocculant growth, with the growing interest in aerobic granular sludge. Aerobic granular sludge is purported to provide superior settling properties, and many of the growth pressures identified for aerobic granular sludge are also present in activated sludge systems. These enhanced settling sludge systems are gaining significant interest, but the factors leading to enhanced sludge settleability could be present in historical and existing systems. Three facilities were evaluated that exhibited enhanced settleability (i.e. sludge volume indices of less than 70 mL/g the majority of the time) to determine how these enhanced settling sludges compare to typical settling curves from the literature. The enhanced settling sludge facilities exhibit key differences related to surface overflow rate, return activated sludge (RAS) pumping requirements, and sensitivity to solids concentration that are critical for developing effective settling designs for enhanced settling sludge facilities. As more facilities aim to achieve enhanced settling sludge for intensification of infrastructure, it will be important to carefully consider historic settling curves and to develop site-specific settling criteria when possible.

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Simulation of Aerobic Granular Sludge Process Efficiency

Revista de Chimie ◽

10.37358/rc.17.8.5752 ◽

2017 ◽

Vol 68 (8) ◽

pp. 1723-1725

Author(s):

Elena Elisabeta Manea ◽

Costel Bumbac ◽

Olga Tiron ◽

Razvan Laurentiu Dinu ◽

Valeriu Robert Badescu

Keyword(s):

Wastewater Treatment ◽

Activated Sludge ◽

Batch Reactor ◽

Granular Sludge ◽

Process Efficiency ◽

Aerobic Granular Sludge ◽

Organic Load ◽

Batch Reactors ◽

Conventional Activated Sludge ◽

Pollutants Removal

Using aerobic granular sludge for wastewater treatment has multiple advantages compared to conventional activated sludge systems, most important being the ability of simultaneous removal of the pollutants responsible for eutrophication: organic load, compounds of nitrogen (NH4+; NO3-) and phosphorus (PO43-). The advantages are currently exploited for developing the next generation of wastewater treatment systems while the identified limitations are approached by experimental and theoretical researches worldwide. The aim of the study consists in evaluating the possibility of predicting the system�s response to different changes in the influent wastewater loadings. The paper presents simulations results backed up by experimental data for pollutants removal efficiencies evaluation for a sequential batch reactor (SBR) with aerobic granular sludge. The mathematical model is based on the activated sludge model no. 3, which was updated by considering the simultaneous biological nitrification (NH4+NO3) and denitrification (NO3-N2) processes, thus complying with the biochemical reactions occurring in aerobic granular sludge sequential batch reactors. The model developed was validated by the experimental results obtained on a laboratory scale SBR monitored for over a month.

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Comparing the performance of aerobic granular sludge versus conventional activated sludge for microbial log removal and effluent quality: Implications for water reuse

Water Research ◽

10.1016/j.watres.2018.08.038 ◽

2018 ◽

Vol 145 ◽

pp. 442-452 ◽

Cited By ~ 9

Author(s):

Benjamin J. Thwaites ◽

Michael D. Short ◽

Richard M. Stuetz ◽

Petra J. Reeve ◽

Juan-Pablo Alvarez Gaitan ◽

...

Keyword(s):

Activated Sludge ◽

Water Reuse ◽

Granular Sludge ◽

Aerobic Granular Sludge ◽

Effluent Quality ◽

Conventional Activated Sludge

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The Characteristics of the Aerobic Granular Sludge on Nitrogen and Phosphorus Removal Simultaneously

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.446-449.2840 ◽

2012 ◽

Vol 446-449 ◽

pp. 2840-2843

Author(s):

Jin Sheng Liu ◽

Yong Jiong Ni ◽

Gen Yuan Jia ◽

Jun Li

Keyword(s):

Activated Sludge ◽

Phosphorus Removal ◽

Operation Mode ◽

Weight Ratio ◽

Granular Sludge ◽

Aerobic Granular Sludge ◽

Nitrogen And Phosphorus ◽

Nitrogen And Phosphorus Removal ◽

Conventional Activated Sludge ◽

Seed Sludge

By using the conventional activated sludge as seed sludge in SBR to cultivate the aerobic granular sludge system, the mechanism of nitrogen and phosphorus removal was explored. The results showed that the aerobic granular sludge system consisted of the heavy aerobic granular sludge and the light flocculent activated sludge was formed in the reactor after 15 days. The SVI of the aerobic granular sludge system was about 50ml/g～60ml/g, the MLSS was about 3000mg/L～4000mg/L steadily, and the weight ratio of granules in the total sludge was about 70%.The removal rates of NH4+-N, TN, and PO43-P in the anaerobic-aerobic operation mode were 80%～97%, 80%～97% and 70%～85%, respectively. It indicated that granules and flocs were beneficial nitrogen and phosphorus removal, respectively.

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Settling behaviour of aerobic granular sludge

Water Science & Technology ◽

10.2166/wst.2007.671 ◽

2007 ◽

Vol 56 (7) ◽

pp. 55-63 ◽

Cited By ~ 22

Author(s):

A. Nor Anuar ◽

Z. Ujang ◽

M.C.M. van Loosdrecht ◽

M.K. de Kreuk

Keyword(s):

Activated Sludge ◽

Batch Reactor ◽

High Capacity ◽

Granular Sludge ◽

Aerobic Granular Sludge ◽

Mechanical Mixing ◽

Sludge Flocs ◽

Conventional Activated Sludge ◽

Biomass Retention ◽

Sludge Settling

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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Anaerobic hydrolysis of complex substrates in full-scale aerobic granular sludge: enzymatic activity determined in different sludge fractions

Applied Microbiology and Biotechnology ◽

10.1007/s00253-021-11443-3 ◽

2021 ◽

Author(s):

Sara Toja Ortega ◽

Mario Pronk ◽

Merle K. de Kreuk

Keyword(s):

Hydrolytic Enzymes ◽

Oxygen Demand ◽

Domestic Wastewater ◽

Granular Sludge ◽

Hydrolytic Activity ◽

Full Scale ◽

Aerobic Granular Sludge ◽

Bulk Liquid ◽

Granule Formation ◽

Hydrolysis Of

Abstract Complex substrates, like proteins, carbohydrates, and lipids, are major components of domestic wastewater, and yet their degradation in biofilm-based wastewater treatment technologies, such as aerobic granular sludge (AGS), is not well understood. Hydrolysis is considered the rate-limiting step in the bioconversion of complex substrates, and as such, it will impact the utilization of a large wastewater COD (chemical oxygen demand) fraction by the biofilms or granules. To study the hydrolysis of complex substrates within these types of biomass, this paper investigates the anaerobic activity of major hydrolytic enzymes in the different sludge fractions of a full-scale AGS reactor. Chromogenic substrates were used under fully mixed anaerobic conditions to determine lipase, protease, α-glucosidase, and β-glucosidase activities in large granules (>1 mm in diameter), small granules (0.2–1 mm), flocculent sludge (0.045–0.2 mm), and bulk liquid. Furthermore, composition and hydrolytic activity of influent wastewater samples were determined. Our results showed an overcapacity of the sludge to hydrolyze wastewater soluble and colloidal polymeric substrates. The highest specific hydrolytic activity was associated with the flocculent sludge fraction (1.5–7.5 times that of large and smaller granules), in agreement with its large available surface area. However, the biomass in the full-scale reactor consisted of 84% large granules, making the large granules account for 55–68% of the total hydrolytic activity potential in the reactor. These observations shine a new light on the contribution of large granules to the conversion of polymeric COD and suggest that large granules can hydrolyze a significant amount of this influent fraction. The anaerobic removal of polymeric soluble and colloidal substrates could clarify the stable granule formation that is observed in full-scale installations, even when those are fed with complex wastewaters. Key points • Large and small granules contain >70% of the hydrolysis potential in an AGS reactor. • Flocculent sludge has high hydrolytic activity but constitutes <10% VS in AGS. • AGS has an overcapacity to hydrolyze complex substrates in domestic wastewater. Graphical abstract

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