Article
Life Cycle Assessment of Bioplastics and Food Waste
Disposal Methods
Shakira R. Hobbs
1,
*, Tyler M. Harris
2
, William J. Barr
3
and Amy E. Landis
4
Citation: Hobbs, S.R.; Harris, T.M.;
Barr, W.J.; Landis, A.E. Life Cycle
Assessment of Bioplastics and Food
Waste Disposal Methods.
Sustainability 2021, 13, 6894. https://
doi.org/10.3390/su13126894
Academic Editor: João Carlos de
Oliveira Matias
Received: 23 April 2021
Accepted: 7 June 2021
Published: 18 June 2021
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1
Civil Engineering Department, College of Engineering, University of Kentucky, Lexington, KY 40506, USA
2
Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, WA 99352, USA;
tyler.harris@pnnl.gov
3
School of Sustainable Engineering and the Built Environment, Arizona State University,
Tempe, AZ 85004, USA; wjbarr@asu.edu
4
Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, CO 80401, USA;
amylandis@mines.edu
* Correspondence: shakirahobbs@uky.edu
Abstract:
The environmental impacts of five waste management scenarios for polylactic acid (PLA)-
based bioplastics and food waste were quantified using life cycle assessment. Laboratory experiments
have demonstrated the potential for a pretreatment process to accelerate the degradation of bioplas-
tics and were modeled in two of the five scenarios assessed. The five scenarios analyzed in this
study were: (1a) Anaerobic digestion (1b) Anaerobic digestion with pretreatment; (2a) Compost;
(2a) Compost with pretreatment; (3) Landfill. Results suggested that food waste and pretreated
bioplastics disposed of with an anaerobic digester offers life cycle and environmental net total bene-
fits (environmental advantages/offsets) in several areas: ecotoxicity (
−
81.38 CTUe), eutrophication
(
0 kg N eq
), cumulative energy demand (
−
1.79 MJ), global warming potential (0.19 kg CO
2
), and
human health non-carcinogenic (
−
2.52 CTuh). Normalized results across all impact categories show
that anaerobically digesting food waste and bioplastics offer the most offsets for ecotoxicity, eutrophi-
cation, cumulative energy demand and non-carcinogenic. Implications from this study can lead to
nutrient and energy recovery from an anaerobic digester that can diversify the types of fertilizers and
decrease landfill waste while decreasing dependency on non-renewable technologies. Thus, using
anaerobic digestion to manage bioplastics and food waste should be further explored as a viable and
sustainable solution for waste management.
Keywords: bioplastics; disposal; LCA
1. Introduction
Waste management options for handling bioplastics are complicated by food waste
contamination. Polylactic acid (PLA)-based service ware is often discarded with food waste,
which makes it difficult to recycle without separation [
1
,
2
]. Sudesh et al. expect biobased
and biodegradable plastic to present a waste management challenge as production and use
continue to increase [
3
]. In addition, there are no current systems that allow bioplastics to
be recycled nationwide, which results in bioplastics being redirected to landfills alongside
other municipal solid waste [
4
]. Sending food waste and biodegradable municipal waste
to landfills is banned in many states in the US and European countries [
5
,
6
]. As food waste
and bioplastics degrade, they emit greenhouse gases such as CO
2
and CH
4
that contribute
to global warming [7–9].
Although bioplastics such as polylactic acid (PLA) are biodegradable they do not
compost as quickly as other organics such as food waste [
10
]. Oftentimes, bioplastics are
screened out of industrial compost facilities and sent to the landfill due to their slow degra-
dation [
4
,
10
]. Previous research suggests that a pretreatment might enable the degradation
of PLA in compost, but this is not a common practice [11].
Sustainability 2021, 13, 6894. https://doi.org/10.3390/su13126894 https://www.mdpi.com/journal/sustainability
