Rheology as Tool for Polymer Dose Assessment and Control

Abu-Orf, Mohammad; Dentel, Steven K.

doi:10.1061/(asce)0733-9372(1999)125:12(1133)

Cited by 61 publications

(47 citation statements)

References 19 publications

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“…The rheological properties of sludge strongly affect sludge treatment and disposal processes, especially hydrodynamic processes, such as mixing, pumping, dewatering, drying and landfilling (Baudez and Coussot, 2001;Chaari et al, 2003;Seyssiecq et al, 2003;Spinosa and Lotito, 2003;Xia et al, 2009). The rheological properties of sludge are not only important design parameters for these processes (Brehmer et al, 2012;€ Ormeci, 2008;Troesch et al, 2009), but also serve as control parameters for the optimization of some treatments, such as sludge conditioning and dewatering (Abu-Orf and Dentel, 1999;Dursun et al, 2004;Marinetti et al, 2010;Ormeci, 2007Ormeci, , 2008Wang and Dentel, 2010). Therefore, the rheological parameters are important in sludge management and treatment processes (Ratkovich et al, 2013).…”

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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Section: Introductionmentioning

confidence: 99%

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

et al. 2016

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“…The initial yield stress peak is associated to the elastic floc network that the polymer creates due to its bridging effect; it is at this yield point where this network also ruptures. The increase in viscosity with increasing polymer dose is also associated to the bridging effect of the conditioning polymer (Abu-Orf and Dentel 1999). Besides, rheological investigations for varying polymer dose provide more reliable result compared to characterization and dewaterability test on the digested sludge (Örmeci 2007).…”

Section: Introductionmentioning

confidence: 97%

Effects of Temperature, Polymer Dose, and Solid Concentration on the Rheological Characteristics and Dewaterability of Digested Sludge of Wastewater Treatment Plant (WWTP)

Yeneneh

Hong

Sen

et al. 2016

Water Air Soil Pollut

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The rheology of digested sludge affects the flow hydrodynamics, dewaterability, and the polymer consumption in wastewater treatment plants. The rheological characteristics of digested sludge are highly dependent on changes in total solid concentration, temperature, and polymer dose. Hence, this study aims at investigating the impacts of total solid concentration, temperature, and polymer dose on the rheological characteristics and the dewaterability of digested sludge. Investigating the relationship between rheological and physicochemical characteristics of sludge can also serve as a tool to optimize essential process parameters. Different homogenized digested sludge samples were subjected to rheological measurement on rotational stresscontrolled rheometer equipped with Peltier concentric cylinder system. The shear stress-shear rate and viscosity-shear rate curves were then developed before and after polymer conditioning at various temperatures and solid concentrations. Different rheological model were fitted to the shear stress-shear rate and viscosity-shear rate rheograms, and the model with the best fitting and more practical significance was selected to determine key rheological parameters. The relationship between dewaterability and digested sludge rheology was also developed. The rheological characteristics of digested sludge during polymer conditioning and flocculation process was significantly affected by temperature and solid concentration; hence, polymer dose can be reduced by operating the dewatering process at optimum temperature condition and varying the polydose as a function of the total solid concentration and viscosity of the digested sludge. The dewaterability as measured in capillary suction time (CST) improved with increasing polymer dose up to 12 kg/t DS but further increase in polymer dose resulted in the deterioration of the dewaterability due to overdosing.

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“…Synthetic sludge is a chemical surrogate that behaves like activated sludge in certain aspects like dewatering, settling and conditioning characteristics, while shows much higher robustness and stability to variable operating conditions [12]. Several studies have been conducted to find appropriate materials for preparation of various types of synthetic sludge and to explore their applications [12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

A new polystyrene-latex-based and EPS-containing synthetic sludge

Wang

Chen

Zheng

et al. 2011

Front. Environ. Sci. Eng.

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Since the living microorganisms in activated sludge continuously change, it is difficult to conduct controlled experiments and achieve reproducible results for evaluating sludge characteristics. Synthetic sludge, as a chemical surrogate to activated sludge, could be used to investigate the sludge physicochemical properties, and it is desirable to prepare synthetic sludge with similar structure and properties to real activated sludge to explore the flocculation and settlement processes in activated sludge systems. In this work, a high-strength synthetic sludge was prepared with functional polystyrene latex particles as the framework and extracellular polymeric substances (EPS) to modify its surface. The flocculation and settling characteristics of the microspheres and the prepared synthetic sludge were tested. Compared with other three functional polystyrene latex microspheres, the synthetic sludge prepared with EPS-modified polystyrene latex microspheres showed good settling characteristics and a significantly higher strength. They could be used for studying the physicochemical properties of activated sludge.

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Rheology as Tool for Polymer Dose Assessment and Control

Cited by 61 publications

References 19 publications

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

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

Effects of Temperature, Polymer Dose, and Solid Concentration on the Rheological Characteristics and Dewaterability of Digested Sludge of Wastewater Treatment Plant (WWTP)

A new polystyrene-latex-based and EPS-containing synthetic sludge

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