The impact of temperature on the rheological behaviour of anaerobic digested sludge

Baudez, Jean-Christophe; Slatter, Paul; Eshtiaghi, Nicky

doi:10.1016/j.cej.2012.10.099

Cited by 88 publications

(68 citation statements)

References 16 publications

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“…The viscosity of the reactor sludge in the control reactor (R2) ranged between 2.0 ± 0.2 and 7.7 ± 0.3 mPa*s throughout the experiment (Fig. 1h), which was in the same range as previously reported values for reactor liquids of processes digesting sewage sludge (Baudez et al 2011(Baudez et al , 2013. It should also be noted that in addition to TS, changes in parameters such as, e.g., particle size, polymeric substances, and ion concentrations, may have contributed to changes in viscosity of the R1 upon codigestion of OFMSW as an additional substrate (Nges et al 2012;Moestedt et al 2016;Lindorfer and Demmig 2016).…”

Section: Resultssupporting

confidence: 75%

Feasibility of OFMSW co-digestion with sewage sludge for increasing biogas production at wastewater treatment plants

Björn

Yekta

Ziels

et al. 2017

Euro-Mediterr J Environ Integr

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Sweden has the ambition to increase its annual biogas production from the current level of 1.9 to 15 TWh by 2030. The unused capacity of existing anaerobic digesters at wastewater treatment plants is among the options to accomplish this goal. This study investigated the feasibility of utilizing the organic fraction of municipal solid waste (OFMSW) as a co-substrate, with primary and waste-activated sewage sludge (PWASS) for production of biogas, corresponding to 3:1 ratio on volatile solid (VS) basis. The results demonstrated that co-digestion of OFMSW with PWASS at an organic loading rate of 5 gVS l −1 day −1 has the potential to increase the biogas production approximately four times. The daily biogas production increased from 1.0 ± 0.1 to 3.8 ± 0.3 l biogas l −1 day −1 , corresponding to a specific methane production of 420 ± 30 Nml methane gVS −1 during the laboratory experiment. Co-digestion of OFMSW with PWASS showed a 50:50 distribution of hydrogenotrophic and aceticlastic methanogens in the digester and enhanced the turnover kinetics of intermediate products (acetate, propionate, and oleate). Practical limitations potentially include the need for sludge dewatering to maintain a sufficient hydraulic retention time (17 days in this study), as well as additional energy consumption for mixing due to an increased sludge apparent viscosity (from 1.8 ± 0.1 to 45 ± 4.8 mPa*s in this study) at elevated OFMSW-loading rates.

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Section: Resultssupporting

confidence: 75%

Feasibility of OFMSW co-digestion with sewage sludge for increasing biogas production at wastewater treatment plants

Björn

Yekta

Ziels

et al. 2017

Euro-Mediterr J Environ Integr

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“…A number of studies demonstrate that also temperature significantly affects the rheological characteristics: sludge becomes progressively more fluid as the temperature increases due to thermal [65,70,71]. These studies also prove that temperature irreversibly modifies the sludge structure.…”

Section: Introductionmentioning

confidence: 86%

Rheology and Microbiology of Sludge from a Thermophilic Aerobic Membrane Reactor

Abbà

Collivignarelli

Manenti

et al. 2017

Journal of Chemistry

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A thermophilic aerobic membrane reactor (TAMR) treating high-strength COD liquid wastes was submitted to an integrated investigation, with the aim of characterizing the biomass and its rheological behaviour. These processes are still scarcely adopted, also because the knowledge of their biology as well as of the physical-chemical properties of the sludge needs to be improved. In this paper, samples of mixed liquor were taken from a TAMR and submitted to fluorescent in situ hybridization for the identification and quantification of main bacterial groups. Measurements were also targeted at flocs features, filamentous bacteria, and microfauna, in order to characterize the sludge. The studied rheological properties were selected as they influence significantly the performances of membrane bioreactors (MBR) and, in particular, of the TAMR systems that operate under thermophilic conditions (i.e., around 50 ∘ C) with high MLSS concentrations (up to 200 gTS L −1 ). The proper description of the rheological behaviour of sludge represents a useful and fundamental aspect that allows characterizing the hydrodynamics of sludge suspension devoted to the optimization of the related processes. Therefore, in this study, the effects on the sludge rheology produced by the biomass concentration, pH, temperature, and aeration were analysed.

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“…Considering the mixing, pumping efficiency and power consumption, the digester design is directly related to the rheology of feeding sludge and digested sludge. However, as described by Baudez et al (2011), most of the investigations focused on the rheology of activated sludge, and the digested sludge rheology was only recently investigated. Due to the viscosity, yield stress, fluid consistency increases with the increase of the solid concentrations (Markis et al, 2014), sludge rheology is particularly important in the AD of concentrated sludge.…”

Section: Introductionmentioning

confidence: 99%

Rheological properties of sewage sludge during enhanced anaerobic digestion with microwave-H2O2 pretreatment

et al. 2016

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a b s t r a c tThe rheological behavior of sludge is of serious concern in anaerobic digestion. This study investigated the rheological properties of sewage sludge during enhanced anaerobic digestion with microwave-H 2 O 2 pretreatment (MW-H 2 O 2 ). The results showed that MW-H 2 O 2 pretreatment resulted in the improvement of sludge flowability and weakening of its viscoelastic properties. Further positive effects on the rheological properties of digested sludge during anaerobic digestion were observed. The flowability was improved with a low level of apparent viscosity. The decrease of the consistency index and increase of the flow behavior index indicated that the strength of the inner structures and non-Newtonian flow characteristics of digested sludge weakened. Both the storage modulus (G 0 ) and loss modulus (G 00 ) decreased, indicating that the viscoelastic behavior became weak. These effects were possibly attributed to the changes of the digested sludge micro-structures, such as extracellular polymeric substances (EPS). This study concluded that anaerobic digestion for treating sewage sludge combined with pretreatment is a more favorable option than single anaerobic digestion from the perspective of rheology.

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The impact of temperature on the rheological behaviour of anaerobic digested sludge

Cited by 88 publications

References 16 publications

Feasibility of OFMSW co-digestion with sewage sludge for increasing biogas production at wastewater treatment plants

Feasibility of OFMSW co-digestion with sewage sludge for increasing biogas production at wastewater treatment plants

Rheology and Microbiology of Sludge from a Thermophilic Aerobic Membrane Reactor

Rheological properties of sewage sludge during enhanced anaerobic digestion with microwave-H2O2 pretreatment

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