Advancing biohydrogen production from organic fraction of municipal solid waste through thermal liquefaction

Abstract

The study aims to examine the sustainability assessment within the circular bioeconomy of biohydrogen production from separated biomass from municipal solid waste (MSW). Successive biohydrogen production from the organic fraction of municipal solid waste (OFMSW) was deployed using hydrothermal liquefication in an innovative small-scale biorefinery system. The biomass was separated by the municipal solid and was dried, shredded, grinded and chopped before conversion. The feedstock was mixed with nickel oxide (5 % w/w) and saturated in distilled water with an 85 % volume-to-mass ratio. Temperature (200–400 °C) and pressure (7–25 MPa) were provided for a retention time of about 60 min with regular agitation. The optimization of parameters produced 207.3 kg of biohydrogen and 17.5 L of bio-oil, respectively. The economic assessment results revealed the feasibility of biohydrogen production with a total revenue of 13,669.02 $ per day and 306,718.4 $ in a month of 22 working days in a single shift of 8 h. The internal cost, capital sum (5,374,575.5 $) and operation cost (169,680.5 $) were calculated to 848,022.7 $. Notably, the top environmental impact emissions were recorded, such as carbon dioxide (CO2), methane (CH4), nitrogen oxides (NOx), carbon monoxide (CO), Non-methane volatile organic compound (NMVOC), particulate matter (PM), and sulfur dioxide with total external cost of 9.15 $. Thus, the life cycle costing was calculated at 848,031.84 $. The economic assessment revealed that photovoltaic energy instead of grid-mix energy reduces the environmental dilemma as Fine particulate matter formation from 0.25 kg PM2.5 eq. to 0.05 kg PM2.5 eq., Terrestrial ecotoxicity from 75.8 kg 1,4-DB eq. to 17.2 kg 1,4-DB eq., and Ionization radiation from 0.22 kBq Co-60 eq. to air to 0.06 kBq Co-60 eq. to air. Thus, it is proven that biohydrogen production from organic fraction of municipal solid waste is a win-win-win situation.