Cost, energy and GHG emission assessment for microbial biodiesel production through valorization of municipal sludge and crude glycerol

• Published in: Bioresource technology 2020-02, Vol.297, p.122404-122404, Article 122404
• Main Authors: Kumar, Lalit R., Yellapu, Sravan K., Tyagi, R.D., Drogui, Patrick
• Format: Article
• Language: English
• Subjects: Biofuels; Biomass; Blended biodiesel; Conventional process; Economic evaluation; Glycerol; INRS process; Lipids; Sewage; Waste carbon sources
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2019.122404

[Display omitted] •B10 unit production cost is $ 0.72/L for INRS process.•Lipid productivity is major cost impacting process parameter.•For 50 million L plant capacity, payback period is less than 5 years.•INRS process is energetically and environmentally viable. In this study, cost simulations were made based on 20 million L blended biodiesel B-10 production per year using INRS and conventional process. In case of INRS process, microbial lipid was produced by T. oleaginosus using washed municipal secondary sludge fortified with crude glycerol while lipid was extracted from wet biomass using biodegradable surfactant and petroleum-diesel (PD). The conventional process uses commercial substrates for lipid production and organic solvents for lipid extraction from dry biomass. The unit B-10 production cost of INRS process was estimated to be $ 0.72/L for an annual capacity of 20 million L, which is 9.5 times more economical than conventional biodiesel production process. For INRS process, the unit B-10 biodiesel production cost was sensitive to plant capacity and lipid productivity during the fermentation. INRS process exhibited positive net energy gain and positive GHG capture, which proves to be energetically and environmentally viable.