Domestic wastewater is a dilute, variable, and complex carbon source for bioprocessing. Despite various treatment technologies, tailored bioprocessing and profiling studies are needed to fully explore its potential. Efficient integration of bioflocculation with anaerobic digestion (AD) is evaluated as a potential platform for small molecules and biogas recovery. Bioflocculation of low strength domestic wastewater (COD ∼ 0.1 g/L) using a bioflocculant resulted in clear water and flocculated sludge, having 30-90 fold increase in Chemical Oxygen Demand (COD). Alkali pretreatment of flocculated sludge (COD ∼ 10 g/L) significantly enhanced biogas production, resulting in a methane yield of 49 %. 1H NMR and GC-MS based profiling demonstrated the desirable impact of bioflocculation and alkali treatment on small molecule abundance. This study establishes an integrated approach that combines bioflocculation, alkali pretreatment, and AD, guided by small molecule profiling, as an effective process for valorizing domestic wastewater into biogas and recoverable organic molecules.
Keywords: ((1)H NMR); Bioflocculation; Biogas; Chemical Oxygen Demand (COD); Domestic wastewater; Gas chromatography-mass spectrometry (GC–MS); Proton-nuclear magnetic resonance.
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