Coffee Ground Residue (CGR) is converted to hydrochar via hydrothermal carbonization.
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Hydrochar was used as additive in anaerobic digestion (AD) of OFMSW.
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Hydrochar shortened the lag phase and increased the degradation of the OFMSW.
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Use of hydrochar from CGR increased methane content of biogas thus improving quality.
Abstract
Stability and in-situ upgrading of biogas in anaerobic digestion (AD) processes using biomass-derived hydrochar as a cheaper alternative is presented. The influence of hydrochar on AD of organic fractions of municipal solid wastes (OFMSWs) was conducted at OLR of 1 kg VS/[m3.d]). The biochemical methane potential of hydrochar was insignificant while digester amended with 20% hydrochar had a longer lag phase, producing biogas after the third day of AD. The total volume of biogas of 464.29 NI/kg oTS in digester containing both OFMSWs and hydrochar was higher when compared with digester without hydrochar (257.62 NI/kg oTS). Likewise, the methane content of digester containing hydrochar was 10% higher. The pH and electrical conductivity in amended digester declined daily from 8.36 to 7.31 and 17.12 to 8.15 mS/cm, respectively. The stability indicators responded positively to the addition of hydrochar to OFMSWs, outperforming other digesters treated with only hydrochar or OFMSWs.
