The Application of Ultrasound as a Pre-Treatment for Anaerobic Digestion

Quarmby, J.; Scott, J. R.; Mason, Andrew K.; Davies, Grant; Parsons, Simon A.

doi:10.1080/09593332008616913

Cited by 34 publications

(24 citation statements)

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“…As a result of the destruction of organic material by the ultrasound, the rate-limiting hydrolysis was enhanced and volatile fatty acids (VFAs) were more readily generated through acidogenesis, subsequently transformed into methane through methanogenesis [21].…”

Section: Anaerobic Digestionmentioning

confidence: 99%

Ultrasonic treatment of waste activated sludge

Dewil

Baeyens

Goutvrind³

2006

Environ. Prog.

110

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Activated sludge processes are key technologies to treat wastewater. These biological processes produce huge amounts of waste activated sludge (WAS), The release of COD from the WAS phase into the filtrate phase is a function of the specific energy input with yields of nearly 30% achievable at SE values of 30,000 kJ/kg DS. A major fraction of the COD is transformed into biodegradable organics (BOD). The reduction in DS fraction of the sludge is proportional to the COD release rates. Although the DS content is reduced, the dewaterability of the sludge is not improved. This reflects itself in increased filtration times during vacuum filtration and in increased values of the capillary suction time (CST

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Section: Anaerobic Digestionmentioning

confidence: 99%

Ultrasonic treatment of waste activated sludge

Dewil

Baeyens

Goutvrind³

2006

Environ. Prog.

110

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“…[19], (~50% increase), [20](15% increase) and [21](13-21% increase). However, the use of different units of energy input makes it difficult to compare the studies.…”

Section: Effects Of Pre-treatmentmentioning

confidence: 99%

Anaerobic treatment of activated sludge from Swedish pulp and paper mills – biogas production potential and limitations

Karlsson

Truong

Gustavsson

et al. 2011

Environmental Technology

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“…Various pre-treatments have been studied and include mechanical, thermal, chemical and biological interventions (Chiu et al 1997, Kopp et al 1997, Tiehm et al 1997, Baier and Schmidheiny 1997, Clark and Nujjoo 1998, Müller et al 1998, Quarmby et al 1999, Barjenburch and Kopplow 2003, Neyens and Baeyens 2003, Climent et al 2007, Dewil et al 2007). All pre-treatments result in a certain degree of lysis or disintegration of sludge cells, hereby releasing and solubilising intracellular material into the water phase and transforming refractory organic compounds into biodegradable material.…”

Section: Introductionmentioning

confidence: 98%

Ultrasonically enhanced anaerobic digestion of waste activated sludge

Appels

Dewil

Baeyens

et al. 2008

International Journal of Sustainable Engineering

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Anaerobic digestion is increasingly applied to stabilise sludge and to reduce operating costs of the wastewater treatment plant by generating biogas, considered as a sustainable energy source. The process suffers from many drawbacks such as slow and incomplete degradation rates, the result of the slow and rate-limiting sludge hydrolysis step, due to the low biodegradability of the cell walls and the presence of extra-cellular biopolymers.Methods to enhance the biogas formation should hence make the substrate more accessible to the anaerobic micro-organisms. Research on increasing the biogas production is extensive, with low-frequency ultrasound treatment emerging as the technical and economic most appropriate technology. Although ultrasound is now widely applied in practice, underlying phenomena and optimum operating conditions are still open to debate. Laboratory ultrasound treatment was coupled with digestion experiments (at 37uC) using 12 parallel digesters, two of them being used as control digesters with untreated sludge.The present paper demonstrates that ultrasound treatment can -within specific ranges of energy-inputachieve (i) an increased disintegration of the sludge, as witnessed by an increasing soluble COD-fraction accompanied by an increasing presence of BOD; (ii) an increased release of volatile fatty acids as a result of the oxidising radicals being formed through cavitation; and (iii) a slightly reduced dewaterability of the residual sludge, needing an increased dosage of poly-electrolyte to obtain a high degree of cake dryness.As pre-treatment to digestion, ultrasound enhances the biogas production by more than 40% at low specific energy-inputs (SE), and approximately 15% at higher SE-values.

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The Application of Ultrasound as a Pre-Treatment for Anaerobic Digestion

Cited by 34 publications

References 0 publications

Ultrasonic treatment of waste activated sludge

Ultrasonic treatment of waste activated sludge

Anaerobic treatment of activated sludge from Swedish pulp and paper mills – biogas production potential and limitations

Ultrasonically enhanced anaerobic digestion of waste activated sludge

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