title: Carbon capture and biogas enhancement by carbon dioxide enrichment of anaerobic digesters treating sewage sludge or food waste.
abstract: The increasing concentration of carbon dioxide (CO2) in the atmosphere and the stringent greenhouse gases (GHG) reduction targets, require the development of CO2 sequestration technologies applicable for the waste and wastewater sector. This study addressed the reduction of CO2 emissions and enhancement of biogas production associated with CO2 enrichment of anaerobic digesters (ADs). The benefits of CO2 enrichment were examined by injecting CO2 at 0, 0.3, 0.6 and 0.9 M fractions into batch ADs treating food waste or sewage sludge. Daily specific methane (CH4) production increased 11-16% for food waste and 96-138% for sewage sludge over the first 24h. Potential CO2 reductions of 8-34% for sewage sludge and 3-11% for food waste were estimated. The capacity of ADs to utilise additional CO2 was demonstrated, which could provide a potential solution for onsite sequestration of CO2 streams while enhancing renewable energy production.
authors.affiliation: Cranfield Water Science Institute, School of Applied Sciences, Cranfield University, Cranfield, Bedfordshire MK43 0AL, UK.
authors.forename: Y
authors.initials: Y
authors.lastname: Bajón Fernández
authors.affiliation: Cranfield Water Science Institute, School of Applied Sciences, Cranfield University, Cranfield, Bedfordshire MK43 0AL, UK.
authors.forename: A
authors.initials: A
authors.lastname: Soares
authors.affiliation: Cranfield Water Science Institute, School of Applied Sciences, Cranfield University, Cranfield, Bedfordshire MK43 0AL, UK.
authors.forename: R
authors.initials: R
authors.lastname: Villa
authors.affiliation: Severn Trent Water, 2 St. John's Street, Coventry CV1 2LZ, UK.
authors.forename: P
authors.initials: P
authors.lastname: Vale
authors.affiliation: Cranfield Water Science Institute, School of Applied Sciences, Cranfield University, Cranfield, Bedfordshire MK43 0AL, UK. Electronic address: E.Cartmell@cranfield.ac.uk.
authors.forename: E
authors.initials: E
authors.lastname: Cartmell
mesh_terms: D000693:Anaerobiosis; D061249:Batch Cell Culture Techniques; D056804:Biofuels; D019149:Bioreactors; D002244:Carbon / Q000032:analysis*; D002245:Carbon Dioxide / Q000032:analysis*; D005502:Food; D005740:Gases / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D008697:Methane / Q000096:biosynthesis; D059205:Renewable Energy; D012722:Sewage / Q000737:chemistry*; D013997:Time Factors; D018505:Waste Management / Q000295:instrumentation* / Q000379:methods*
chemical_list: D056804:Biofuels; D005740:Gases; D012722:Sewage; D002245:Carbon Dioxide; D002244:Carbon; D008697:Methane
keywords: Anaerobic digestion; Carbon dioxide sequestration; Food waste; Methane enhancement; Sewage sludge