Long-term monitoring of a full-scale municipal membrane bioreactor—Characterisation of foulants and operational performance

Lyko, Sven; Wintgens, Thomas; Al-Halbouni, Djamila; Baumgarten, Sven; Tacke, Daniela; Drensla, K.; Janot, Andreas; Dott, Wolfgang; Pinnekamp, Johannes; Melin, Thomas

doi:10.1016/j.memsci.2007.07.008

Cited by 148 publications

(58 citation statements)

References 18 publications

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“…The latter conclusion was also obtained by authors monitoring filterability and SMP in full-scale installations (Lyko et al, 2008, Moreau, 2010. Successful predictions of filterability were only obtained when a combination of parameters was taken into account (Van den Broeck et al, 2011).…”

Section: Smpsupporting

confidence: 60%

Impact of suspended solids concentration on sludge filterability in full-scale membrane bioreactors

Lousada-Ferreira

Lier

Graaf³

2015

Journal of Membrane Science

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The relation between activated sludge filterability and mixed liquor suspended solids (MLSS) concentration in membrane bioreactors (MBRs) is framed in a single hypothesis, explaining results seemingly contradictory. A total of 44 activated sludge samples were collected and analyzed on a variety of parameters, i.e. filterability, MLSS concentration, soluble microbial products (SMP) concentrations and particle size distribution in the range of 2-100 μm and of 0.4-5.0 μm. The sludge filterability was assessed by using the Delft Filtration Characterization method (DFCm). In order to investigate the impact of MLSS concentration, identical samples were diluted with permeate. Results showed that dilution of the samples led to an increased activated sludge filterability, but only when the starting MLSS concentration was below the apparent critical value of 10.5 g/L. As opposed, the filterability of sludge with MLSS concentrations above 10.5 g/L, and which was characterized by a moderate to good filtration quality, i.e. R 20 <1 [x10 12 m -1 ], worsened when diluted. The specific resistance times the particle concentration of a cake layer obtained when filtrating sludge of moderate to good filterability and MLSS concentration above the apparent critical value, was 5.5 times smaller compared to the cake layer of sludge with MLSS concentration below the critical value. Results from SMP assessment and particle counting in the range 2-100 µm showed that reduction in sludge mass and de-flocculation occurred, upon dilution of all samples. However, when diluting sludge samples with MLSS concentrations exceeding 10.5 g/L and which were characterized by a moderate to good filtration characteristics, there was also release of particles below 0.4 µm, opposite to dilutions of samples with MLSS concentrations below 10.5 g/L. We postulate that sludge, which is characterized by a moderate to good filterability, having an MLSS concentration above the apparent critical value of 10.5 g/L, is likely to retain particles smaller than 0.4 μm in its mass, as opposed to sludge with MLSS concentration below the apparent critical value. Our work indicates that there are optimal MLSS concentration ranges in MBR technology, to promote good filterable sludge quality in order to avoid fouling.

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Section: Smpsupporting

confidence: 60%

Impact of suspended solids concentration on sludge filterability in full-scale membrane bioreactors

Lousada-Ferreira

Lier

Graaf³

2015

Journal of Membrane Science

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“…According to our previous study, the solubilization of organic matters by sludge floc lysis with oxidation of peroxides may lead to the gradual transformation from TB-EPS to LB-EPS then to SEPS. Furthermore, it was reported that the high molecular weight biopolymer in SEPS had a more crucial influence on sludge filtration properties (Lyko et al, 2008). Raynaud et al (2012) suggested that a sludge with poor filterability is usually related to such flocs with a loose packing, less fine particle retention and a more compressible cake structure.…”

Section: Effects Of Cao 2 Dosage On Eps Distribution and Compositionmentioning

confidence: 99%

Enhancement of waste activated sludge dewaterability using calcium peroxide pre-oxidation and chemical re-flocculation

et al. 2016

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a b s t r a c tThe effects of combined calcium peroxide (CaO 2 ) oxidation with chemical re-flocculation on dewatering performance and physicochemical properties of waste activated sludge was investigated in this study. The evolutions of extracellular polymeric substances (EPS) distribution, composition and morphological properties were analyzed to unravel the sludge conditioning mechanism. It was found that sludge filtration performance was enhanced by calcium peroxide oxidation with the optimal dosage of 20 mg/ gTSS. However, this enhancement was not observed at lower dosages due to the absence of oxidation and the performance deteriorated at higher dosages because of the release of excess EPS, mainly as proteinlike substances. The variation in soluble EPS (SEPS) component can be fitted well with pseudo-zero-order kinetic model under CaO 2 treatment. At the same time, extractable EPS content (SEPS and loosely bound EPS (LB-EPS)) were dramatically increased, indicating sludge flocs were effectively broken and their structure became looser after CaO 2 addition. The sludge floc structure was reconstructed and sludge dewaterability was significantly enhanced using chemical re-flocculation (polyaluminium chloride (PACl), ferric iron (FeCl 3 ) and polyacrylamide (PAM)). The inorganic coagulants performed better in improving sludge filtration dewatering performance and reducing cake moisture content than organic polymer, since they could act as skeleton builders and decrease the sludge compressibility.

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“…HPSEC. EPS can be divided into three parts according to molecular weight distribution: macromolecular fraction (>4000Da)-mainly consisting of carbohydrates and proteins, mid molecular fraction (1000e4000Da)-consisting of humic substances and peptides, low molecular fraction (<1000Da) -consisting of building blocks and organic acids (Lyko et al, 2008). The variation a The dosages of aluminum salt coagulants were 0.05gAl/gTSS, SEPS and LB-EPS samples were diluted by 10 times, and TB-EPS sample was diluted by 100 times.…”

Section: Eps Compositionmentioning

confidence: 99%

Wastewater sludge dewaterability enhancement using hydroxyl aluminum conditioning: Role of aluminum speciation

et al. 2016

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a b s t r a c tChemical conditioning is one of the most important processes for improve the performance of sludge dewatering device. Aluminum salt coagulant has been widely used in wastewater and sludge treatment. It is generally accepted that pre-formed speciation of aluminum salt coagulants (ASC) has an important influence on coagulation/flocculation performance. In this study, the interaction mechanisms between sludge particles and aluminum salt coagulants with different speciation of hydroxy aluminum were investigated by characterizing the changes in morphological and EPS properties. It was found that middle polymer state aluminum (Al b ) and high polymer state aluminum (Al c ) performed better than monomer aluminum and oligomeric state aluminum (Al a ) in reduction of specific resistance to filtration (SRF) and compressibility of wastewater sludge due to their higher charge neutralization and formed more compact flocs. Sludge was significantly acidified after addition Al a , while pH was much more stable under Al b and Al c conditioning due to their hydrolysis stability. The size of sludge flocs conditioned with Al b and Al c was small but flocs structure was denser and more compact, and floc strength is higher, while that formed from Al a is relatively large, but floc structure was loose, floc strength is relatively lower. Scanning environmental microscope analysis revealed that sludge flocs conditioned by Al b and Al c (especially PAC 2.5 and Al 13 ) exhibited obvious botryoidal structure, this is because sludge flocs formed by Al b and Al c were more compact and floc strength is high, it was easy generated plentiful tiny channels for water release. In addition, polymeric aluminum salt coagulant (Al b , Al c ) had better performance in compressing extracellular polymeric substances (EPS) structure and removing sticky protein-like substances from soluble EPS fraction, contributing to improvement of sludge filtration performance. Therefore, this study provides a novel solution for improving sludge dewatering property by controlling aluminum speciation.

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Long-term monitoring of a full-scale municipal membrane bioreactor—Characterisation of foulants and operational performance

Cited by 148 publications

References 18 publications

Impact of suspended solids concentration on sludge filterability in full-scale membrane bioreactors

Impact of suspended solids concentration on sludge filterability in full-scale membrane bioreactors

Enhancement of waste activated sludge dewaterability using calcium peroxide pre-oxidation and chemical re-flocculation

Wastewater sludge dewaterability enhancement using hydroxyl aluminum conditioning: Role of aluminum speciation

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