title: Comprehensive monitoring and management of a long-term thermophilic CSTR treating coffee grounds, coffee liquid, milk waste, and municipal sludge.
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 ∼ 70 g/L) of coffee grounds, coffee wastewater, milk waste and municipal sludge and it was operated under 55 °C for 225 days. A steady state was achieved under HRT 30 days and OLR 4.0 kg-COD/m(3)/d. However, there was an 35 days inhibition with VFA accumulation (propionic acid 700-1900 mg/L) when doubling the OLR by shortening HRT to 15 days. But, an addition of microelements and sulfate (0.5 g/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.
authors.affiliation: Department of Environmental Science, Graduate School of Environmental Studies, Tohoku University, Japan.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Shofie
authors.affiliation: College of Engineering, China Agriculture University, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Qiao
authors.affiliation: Key Lab. of Northwest Water Resource, Environment and Ecology, Xi'an University of Architecture and Technology, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Li
authors.affiliation: Department of Civil and Environmental Engineering, School of Engineering, Tohoku University, Japan.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Takayanagi
authors.affiliation: Department of Environmental Science, Graduate School of Environmental Studies, Tohoku University, Japan; Department of Civil and Environmental Engineering, School of Engineering, Tohoku University, Japan.
authors.forename: Yu-You
authors.initials: YY
authors.lastname: Li
mesh_terms: D000818:Animals; D056804:Biofuels / Q000032:analysis; D019149:Bioreactors; D003069:Coffee / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry; D008892:Milk / Q000737:chemistry*; D011422:Propionates / Q000737:chemistry; D012722:Sewage / Q000737:chemistry*; D013431:Sulfates / Q000737:chemistry; D013696:Temperature; D014865:Waste Disposal, Fluid / Q000379:methods
chemical_list: D056804:Biofuels; D003069:Coffee; D011422:Propionates; D012722:Sewage; D013431:Sulfates; D006859:Hydrogen; C029658:propionic acid
keywords: CSTR; Coffee residues; Stability; Thermophilic