Effect of mixing regimes on cow manure digestion in impeller mixed, unmixed and Chinese dome digesters

Abiodun O. Jegede, Grietje Zeeman, Harry Bruning

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

This study examines the effect of mixing on the performance of anaerobic digestion of cow manure in Chinese dome digesters (CDDs) at ambient temperatures (27–32 C) in comparison with impeller mixed digesters (STRs) and unmixed digesters (UMDs) at the laboratory scale. The CDD is a type of household digester used in rural and pre-urban areas of developing countries for cooking. They are mixed by hydraulic variation during gas production and gas use. Six digesters (two of each type) were operated at two different influent total solids (TS) concentration, at a hydraulic retention time (HRT) of 30 days for 319 days. The STRs were mixed at 55 rpm, 10 min/hour; the unmixed digesters were not mixed, and the Chinese dome digesters were mixed once a day releasing the stored biogas under pressure. The reactors exhibited different specific biogas production and treatment efficiencies at steady state conditions. The STR 1 exhibited the highest methane (CH4) production and treatment efficiency (volatile solid (VS) reduction), followed by STR 2. The CDDs performed better (10% more methane) than the UMDs, but less (approx. 8%) compared to STRs. The mixing regime via hydraulic variation in the CDD was limited despite a higher volumetric biogas rate and therefore requires optimization.

LanguageEnglish
Article number2540
JournalEnergies
Volume12
Issue number13
DOIs
Publication statusPublished - 2 Jul 2019

Fingerprint

Dome
Manures
Domes
Biogas
Hydraulics
Methane
Anaerobic digestion
Volatiles
Cooking
Urban Areas
Developing Countries
Gases
Developing countries
Reactor
Optimization
Temperature

Keywords

  • Chinese dome digester
  • Hydraulically mixed
  • Impeller mixed digester
  • Mixing
  • Total solids (TS) concentration
  • Unstirred digester

Cite this

@article{98ea801e305b4f44a101539ab2978467,
title = "Effect of mixing regimes on cow manure digestion in impeller mixed, unmixed and Chinese dome digesters",
abstract = "This study examines the effect of mixing on the performance of anaerobic digestion of cow manure in Chinese dome digesters (CDDs) at ambient temperatures (27–32 ◦C) in comparison with impeller mixed digesters (STRs) and unmixed digesters (UMDs) at the laboratory scale. The CDD is a type of household digester used in rural and pre-urban areas of developing countries for cooking. They are mixed by hydraulic variation during gas production and gas use. Six digesters (two of each type) were operated at two different influent total solids (TS) concentration, at a hydraulic retention time (HRT) of 30 days for 319 days. The STRs were mixed at 55 rpm, 10 min/hour; the unmixed digesters were not mixed, and the Chinese dome digesters were mixed once a day releasing the stored biogas under pressure. The reactors exhibited different specific biogas production and treatment efficiencies at steady state conditions. The STR 1 exhibited the highest methane (CH4) production and treatment efficiency (volatile solid (VS) reduction), followed by STR 2. The CDDs performed better (10{\%} more methane) than the UMDs, but less (approx. 8{\%}) compared to STRs. The mixing regime via hydraulic variation in the CDD was limited despite a higher volumetric biogas rate and therefore requires optimization.",
keywords = "Chinese dome digester, Hydraulically mixed, Impeller mixed digester, Mixing, Total solids (TS) concentration, Unstirred digester",
author = "Jegede, {Abiodun O.} and Grietje Zeeman and Harry Bruning",
year = "2019",
month = "7",
day = "2",
doi = "10.3390/en12132540",
language = "English",
volume = "12",
journal = "Energies",
issn = "1996-1073",
publisher = "MDPI",
number = "13",

}

Effect of mixing regimes on cow manure digestion in impeller mixed, unmixed and Chinese dome digesters. / Jegede, Abiodun O.; Zeeman, Grietje; Bruning, Harry.

In: Energies, Vol. 12, No. 13, 2540, 02.07.2019.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Effect of mixing regimes on cow manure digestion in impeller mixed, unmixed and Chinese dome digesters

AU - Jegede, Abiodun O.

AU - Zeeman, Grietje

AU - Bruning, Harry

PY - 2019/7/2

Y1 - 2019/7/2

N2 - This study examines the effect of mixing on the performance of anaerobic digestion of cow manure in Chinese dome digesters (CDDs) at ambient temperatures (27–32 ◦C) in comparison with impeller mixed digesters (STRs) and unmixed digesters (UMDs) at the laboratory scale. The CDD is a type of household digester used in rural and pre-urban areas of developing countries for cooking. They are mixed by hydraulic variation during gas production and gas use. Six digesters (two of each type) were operated at two different influent total solids (TS) concentration, at a hydraulic retention time (HRT) of 30 days for 319 days. The STRs were mixed at 55 rpm, 10 min/hour; the unmixed digesters were not mixed, and the Chinese dome digesters were mixed once a day releasing the stored biogas under pressure. The reactors exhibited different specific biogas production and treatment efficiencies at steady state conditions. The STR 1 exhibited the highest methane (CH4) production and treatment efficiency (volatile solid (VS) reduction), followed by STR 2. The CDDs performed better (10% more methane) than the UMDs, but less (approx. 8%) compared to STRs. The mixing regime via hydraulic variation in the CDD was limited despite a higher volumetric biogas rate and therefore requires optimization.

AB - This study examines the effect of mixing on the performance of anaerobic digestion of cow manure in Chinese dome digesters (CDDs) at ambient temperatures (27–32 ◦C) in comparison with impeller mixed digesters (STRs) and unmixed digesters (UMDs) at the laboratory scale. The CDD is a type of household digester used in rural and pre-urban areas of developing countries for cooking. They are mixed by hydraulic variation during gas production and gas use. Six digesters (two of each type) were operated at two different influent total solids (TS) concentration, at a hydraulic retention time (HRT) of 30 days for 319 days. The STRs were mixed at 55 rpm, 10 min/hour; the unmixed digesters were not mixed, and the Chinese dome digesters were mixed once a day releasing the stored biogas under pressure. The reactors exhibited different specific biogas production and treatment efficiencies at steady state conditions. The STR 1 exhibited the highest methane (CH4) production and treatment efficiency (volatile solid (VS) reduction), followed by STR 2. The CDDs performed better (10% more methane) than the UMDs, but less (approx. 8%) compared to STRs. The mixing regime via hydraulic variation in the CDD was limited despite a higher volumetric biogas rate and therefore requires optimization.

KW - Chinese dome digester

KW - Hydraulically mixed

KW - Impeller mixed digester

KW - Mixing

KW - Total solids (TS) concentration

KW - Unstirred digester

U2 - 10.3390/en12132540

DO - 10.3390/en12132540

M3 - Article

VL - 12

JO - Energies

T2 - Energies

JF - Energies

SN - 1996-1073

IS - 13

M1 - 2540

ER -