Environmental Impact Assessment of the Polylactic Acid Bioplastic Production of Sweet Sorghum Juice

Author : Macatula, Maricon M.
Major Adviser : Gatdula, Kristel M.
Committee Members : Guerrero, Gino Apollo M.; Migo, Veronica P.
Year : 2021
Month : August
Type : Thesis
Degree: BS
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The cradle-to-gate Life Cycle Assessment (LCA) of the Polylactic Acid (PLA) bioplastic production from sweet sorghum was conducted to determine its effect on the environment. The key parameters involve in each of the unit processes are determine in the inventory analysis, while their emissions in specific equivalence unit is calculated in the impact assessment by multiplying the emission factor of a material with its calculated value in the material and energy balance. The environmental impact categories considered are the global warming potential (GWP), eutrophication potential (EP) and acidification potential (AP), which are analyzed based on a functional unit of one harvest in one hectare. The GWP calculated for this process is 1087.9 kg CO₂ eq, with around 45% coming from the fermentation step. For EP and AP, only the biggest contributor based on previous studies are considered. The EP calculated is 29.00295 kg PO4⁻³ eq, while the AP computed is 35.36 SO₂ eq. The PLA product generated was compared in terms of GWP and total energy usage (TEU) with polystyrene (PS), polyethylene terephthalate (PET), high-density polyethylene (HDPE) and low-density polyethylene (LDPE) which are fossil-based plastics with comparable characteristics with PLA bioplastics. Results show lower GWP and TEU of 12-38% and 76-92% respectively. Standardization of different factors in LCA and considering other environmental impact categories can improve the analysis.

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