Comprehensive monitoring and management of a long-term thermophilic CSTR treating coffee grounds, coffee liquid, milk waste, and municipal sludge

Mohammad Shofie, Wei Qiao, Qian Li, Kazuyuki Takayanagi, Yu You Li

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)

Abstract

The CSTR process has previously not been successfully applied to treat coffee residues under thermophilic temperature and long term operation. In this experiment, the CSTR was fed with mixture substrate (TS~70g/L) of coffee grounds, coffee wastewater, milk waste and municipal sludge and it was operated under 55°C for 225days. A steady state was achieved under HRT 30days and OLR 4.0kg-COD/m3/d. However, there was an 35days inhibition with VFA accumulation (propionic acid 700-1900mg/L) when doubling the OLR by shortening HRT to 15days. But, an addition of microelements and sulfate (0.5g/L) in feedstock increased reactor resilience and stability under high loading rate and propionic acid stress. Continuous monitoring of hydrogen in biogas indicated the imbalance of acetogenesis. The effectiveness of comprehensive parameters (total VFA, propionic acid, IA/PA, IA/TA and CH4 content) was proved to manage the thermophilic system.

Original languageEnglish
Pages (from-to)202-211
Number of pages10
JournalBioresource Technology
Volume192
DOIs
Publication statusPublished - 2015 Sep 1

Keywords

  • CSTR
  • Coffee residues
  • Stability
  • Thermophilic

ASJC Scopus subject areas

  • Bioengineering
  • Environmental Engineering
  • Renewable Energy, Sustainability and the Environment
  • Waste Management and Disposal

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