From pre-treatment to co-treatment - How successful is ultrasonication of digested sewage sludge in continuously operated anaerobic digesters?

Thomas Lippert, Jochen Bandelin, Yunqi Xu, Yu Chen Liu, Gabriel Hernández Robles, Jörg E. Drewes and Konrad Koch

Renewable Energy, 2020, vol. 166, issue C, 56-65

Abstract: The present study assessed the performance of ultrasonic co-treatment, i.e., the treatment of digested sewage sludge in continuously operated anaerobic digesters. Experiments were carried out using a non-sonicated control digester and a sonicated test digester. The test digester received side-stream sonication (∼10% of reactor volume per day) at a specific energy input of 2,000 kJ/kgTS. Treatment effects were monitored based on (i) specific methane production, (ii) (volatile) solids removal, and (iii) digestate dewaterability. Results revealed that co-treatment significantly enhanced average methane production (+6%), volatile solids removal (+9%), and solids reduction in the digestate (−5%). However, due to the only moderate enhancement and the relatively high energy input, the average cost recovery (i.e., the ratio between electricity costs and benefits due to additional methane and improved solids removal) was only 6%–9%, depending on the assumed disposal costs. Moreover, as sonication led to impaired digestate dewaterability (average increase in normalized capillary suction time of 14%), the cost recovery due to reduced residual sludge might be negated again by lower dewatering efficiency. Overall, co-treatment seemed not economical under the conditions investigated. To render co-treatments economically feasible, further research, especially exploring the potential of low energy input sonication, is required.

Keywords: Anaerobic digestion; Ultrasonic treatment; Methane production; (Volatile) solids removal; Sludge dewaterability (search for similar items in EconPapers)
Date: 2020
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (2)

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0960148120318802
Full text for ScienceDirect subscribers only

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:eee:renene:v:166:y:2020:i:c:p:56-65

DOI: 10.1016/j.renene.2020.11.128

Access Statistics for this article

Renewable Energy is currently edited by Soteris A. Kalogirou and Paul Christodoulides

More articles in Renewable Energy from Elsevier
Bibliographic data for series maintained by Catherine Liu ().