Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Anaerobic digestion trials with HTC process water
Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
2017 (English)Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesisAlternative title
Rötningsförsök med HTC processvatten (Swedish)
Abstract [en]

Hydrothermal carbonization (HTC) is a process where elevated temperature and pressure is used in order to convert biomass to hydrochar, a coal-like substance with good dewatering properties and many potential uses. HTC can be used to treat digestate from anaerobic digestion, but the process water that remains after the hydrochar has been recovered needs to be treated further in the wastewater treatment plant. In order to make HTC more competitive compared to other sludge treatments it is important to find a good use for the process water. The main objective of this master thesis was to investigate the effects of recirculating HTC process water to the anaerobic digestion.

To achieve the objective, both theoretical calculations and experimental trials were performed. The experimental trials were conducted with an Automatic Methane Potential Test System (AMPTS II) in order to investigate the anaerobic digestion in laboratory scale. In the first trial, three substrates, process water, hydrochar, and primary sludge were tested for their biochemical methane potential (BMP). All substrates were mixed with inoculum. Process water had a BMP of 335 ± 10 % NmL/gvs (normalized CH4 production in mL per g added VS (volatile solids)), hydrochar had BMP of 150 ± 5 % NmL/gvs, and primary sludge had a BMP of 343 ± 2 % NmL/gvs. The methane production was almost the same for process water as for primary sludge i.e. no inhibitory effects could be seen when process water was mixed with only inoculum.

In the second trial, a more realistic scenario was tested where process water was co-digested with primary sludge at different ratios. The results from the second trial were not statistically reliable and therefore cannot be used on their own to determine with certainty if the process water could have an inhibitory effect in a full-scale anaerobic digester. However, the combined results from both trials indicate that it is unlikely that the process water would have an inhibitory effect.

The possible increase in methane yield, if the digestate from a biogas facility was treated in full-scale implementation of the HTC process, was calculated theoretically. The produced process water would have the capacity to increase the methane production with approximately 10 % for a biogas facility. For the calculations, the BMP for process water was assumed to be 335 NmL/gvs and no synergetic effects was considered.

Place, publisher, year, edition, pages
2017. , p. 58
Series
UPTEC W, ISSN 1401-5765 ; 17008
Keywords [en]
anaerobic digestion, HTC, process water, hydrochar, AMPTS, BMP, primary sludge, digestate
Keywords [sv]
rötning, HTC, processvatten, biokol, AMPTS, BMP, primärslam, rötningsslam
National Category
Other Engineering and Technologies not elsewhere specified
Identifiers
URN: urn:nbn:se:uu:diva-325289OAI: oai:DiVA.org:uu-325289DiVA, id: diva2:1114110
External cooperation
IVL, svenska miljöinstitutet; C-Green
Educational program
Master Programme in Environmental and Water Engineering
Presentation
2017-06-13, Skåne, Villavägen 16, 752 36 Uppsala, 13:15 (Swedish)
Supervisors
Examiners
Available from: 2017-06-22 Created: 2017-06-22 Last updated: 2017-06-22Bibliographically approved

Open Access in DiVA

Erik_Nilsson(2871 kB)124 downloads
File information
File name FULLTEXT01.pdfFile size 2871 kBChecksum SHA-512
46aacad1b81559fb6542f1e8027abff0e9caaab26c52add5318199cb052e31ed54cfb9bb3a4f520794ccde8cbfcb26ca2db16acc5846900da1899036f47c459a
Type fulltextMimetype application/pdf

By organisation
Department of Earth Sciences
Other Engineering and Technologies not elsewhere specified

Search outside of DiVA

GoogleGoogle Scholar
Total: 124 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

urn-nbn

Altmetric score

urn-nbn
Total: 393 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf