Modelling the electro-osmotically enhanced pressure dewatering of activated sludge

Curvers, Daan; Maes, Katrien; Saveyn, Hans; Baets, Bernard De; Meeren, Paul Van der

doi:10.1016/j.ces.2006.12.085

Cited by 33 publications

(21 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Filtrations were performed on a lab-scale dead-end filtration setup, described in more detail in [29]. The displacement of the piston was used to monitor the filtrate volume.…”

Section: Filtrate Conductivitymentioning

confidence: 99%

Compressibility of biotic sludges – An osmotic approach

Curvers

Saveyn

Scales

et al. 2011

Chemical Engineering Journal

View full text Add to dashboard Cite

“…Filtrations were performed on a lab-scale dead-end filtration setup, described in more detail in [29]. The displacement of the piston was used to monitor the filtrate volume.…”

Section: Filtrate Conductivitymentioning

confidence: 99%

Compressibility of biotic sludges – An osmotic approach

Curvers

Saveyn

Scales

et al. 2011

Chemical Engineering Journal

View full text Add to dashboard Cite

“…As they move towards the cathode, they drag and push the water molecules in the pores, resulting in a net transport of water towards the cathode [4,5] .…”

mentioning

confidence: 99%

mentioning

confidence: 99%

“…Curvers et al [4] proposed a model which described the height of compressible materials as a function of time in a period when pressure dewatering was assisted by a DC electric field. Iwata et al [6] developed a model for electroosmotic dewatering of a filter cake that is assumed to possess a homogeneous porosity distribution after 24 h preconsolidation, but the model cannot be adopted for realistic dewatering, involving the simultaneous action of filtration and expression as well as electroosmotic dewatering in a single process.…”

mentioning

confidence: 99%

“…When an electric field is applied to sludge cake, the particles stay trapped in the cake matrix, but the positive counterions are attracted by the cathode. As they move towards the cathode, they drag and push the water molecules in the pores, resulting in a net transport of water towards the cathode [4,5] .Electroosmotic dewatering has been widely studied, but the modelling of the process has received little attention. Curvers et al [4] proposed a model which described the height of compressible materials as a function of time in a period when pressure dewatering was assisted by a DC electric field.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Mathematical model for electroosmotic dewatering of activated sludge

Zhang

Zheng

et al. 2011

Trans. Tianjin Univ.

View full text Add to dashboard Cite

Abstract：The mechanical dewatering of activated sludge is difficult due to its high compressibility, which can be improved by electroosmosis. In electroosmosis, direct electric field is applied to sludge cake. Based on the conductivity modes of different sludge beds, a model is presented in which sludge cake consists of two series parts in the circuit: a dewatered bed and an undewatered one. The dewatered bed called solid conductor is mainly made up of immovable water and sludge particles. The undewatered bed includes movable water and solid conductor, which are connected in parallel in the circuit. The model describes the variation of water content with time and electric power consumption as a function of water content in sludge cake, and interprets the reason for the variation of electroosmotic dewatering rate. Comparison with the experimental data for electroosmotic dewatering under constant voltage supports the validity of the model. Sludge production from wastewater treatment plants has been increasing in recent years in China, bringing lots of problems to city environment. Although sludge had been flocculated and mechanically dewatered, the water content in sludge cake was 80% (mass ratio) or higher, whereas water content in dewatered sludge cake should be less than 60% for disposal [1] . Thus, further dewatering is necessary. Currently, the thermal drying method is often considered sufficient to remove capillary and vicinal water. However, capital and operating costs of this method are high [2] . Electroosmosis technique offers a potential cost-effective solution, which can be applied to remove the capillary and vicinal water. In addition, the process does not involve phase change, thus making it more favorable because of its lower energy consumption than thermal drying [3] .Electroosmotic dewatering is based on the surface charge of sludge and applied electric field. The sludge particles with a negative surface are surrounded by a layer of positive charges, forming electric double layers. When an electric field is applied to sludge cake, the particles stay trapped in the cake matrix, but the positive counterions are attracted by the cathode. As they move towards the cathode, they drag and push the water molecules in the pores, resulting in a net transport of water towards the cathode [4,5] .Electroosmotic dewatering has been widely studied, but the modelling of the process has received little attention. Curvers et al [4] proposed a model which described the height of compressible materials as a function of time in a period when pressure dewatering was assisted by a DC electric field. Iwata et al [6] developed a model for electroosmotic dewatering of a filter cake that is assumed to possess a homogeneous porosity distribution after 24 h preconsolidation, but the model cannot be adopted for realistic dewatering, involving the simultaneous action of filtration and expression as well as electroosmotic dewatering in a single process. Yoshida et al [7] constructed the design equations for electroosmotic dewa...

show abstract