Valorization of the organic fraction of municipal solid waste for fumaric acid production and electrochemical membrane extraction using Candida blankii

AbstractThe management of municipal solid waste is a major logistic and environmental problem worldwide. Nonetheless, the organic fraction of municipal solid waste (OFMSW) is a valuable source of nutrients which can be used for a variety of purposes, according to the Circular Economy paradigm. Among the possible applications, the bioproduction of a biodegradable polyester, poly(3-hydroxybutyrate) [P(3HB)], using OFMSW as carbon platform is a promising strategy. Here, an economic and environmental assessment of bacterial P(3HB) production from OFMSW is presented based on previously published results. The SuperPro Designer® software was used to simulate P(3HB) production under our experimental parameters. Two scenarios were proposed depending on the fermentation medium: (1) enzymatic hydrolysate of OFMSW supplemented with glucose and plum waste juice; and (2) basal medium supplemented with glucose and plum waste juice. According to our results, both scenarios are not economically feasible under our experimental parameters. In Scenario 1, the low fermentation yield, the cost of the enzymes, the labour cost and the energy consumption are the factors that most contribute to that result. In Scenario 2, the cost of the extraction solvent and the low fermentation yield are the most limiting factors. The possibility of using process waste as raw material for the generation of other products must be investigated to enhance economic feasibility. From an environmental viewpoint, the photochemical oxidation potential (derived from the use of anisole as extraction solvent) and the generation of acid rain and global warming effect (caused by the burning of fuels for power generation) are the most relevant impacts associated to P(3HB) production under our experimental parameters.

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Environmental impact assessment of organic fraction of municipal solid waste treatment by anaerobic digestion in Sri Lanka

Waste Management & Research ◽

10.1177/0734242x211013405 ◽

2021 ◽

pp. 0734242X2110134

Author(s):

Rasangika Thathsaranee Weligama Thuppahige ◽

Sandhya Babel

Keyword(s):

Anaerobic Digestion ◽

Sri Lanka ◽

Environmental Impact ◽

Municipal Solid Waste ◽

Solid Waste ◽

Resource Scarcity ◽

Policy Formation ◽

Ozone Formation ◽

Organic Fraction ◽

Management Options

The management of organic fraction of municipal solid waste (OFMSW) has continued to be a significant challenge in Sri Lanka. Anaerobic digestion is one of the management options of OFMSW. However, it generates unavoidable environmental impacts that should be addressed. The present study focuses to assess the environmental impact of a full-scale anaerobic digestion plant in Sri Lanka from a life cycle perspective. The inventory data were obtained from direct interviews and field measurements. Environmental burdens were found to be in terms of global warming potential (230 kg CO2 eq) ozone formation on human health (6.15 × 10−6 kg NO x eq), freshwater eutrophication (2.92 × 10−3 kg P eq), freshwater ecotoxicity (9.27 × 10−5 kg 1,4 DCB eq), human carcinogenic toxicity (3.98 × 10−4 kg 1,4 DCB eq), land use (1.32 × 10−4 m2 a crop eq) and water consumption (2.23 × 10−2 m3). The stratospheric ozone depletion, fine particulate matter formation, ozone formation on terrestrial ecosystems, terrestrial acidification, marine eutrophication, ecotoxicity (terrestrial and marine), human non-carcinogenic toxicity, mineral resource scarcity and fossil resource scarcity, were avoided due to electricity production. Results show that the direct gaseous emissions and digestate generation should be addressed in order to reduce the burdens from the anaerobic digestion plant. Finally, the results of the study could help in policy formation and decision-making in selecting future waste management systems in Sri Lanka.

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