Following the industrial revolution, major economic and populational growth took place,
and, therefore, solid waste generation increased exponentially. Nowadays, waste management still
generates major impacts because the current wide offer of waste management strategies includes
many solutions that produce suboptimal results, such as landfill or waste incineration. From a
circular economy perspective, composting is a potentially sustainable option to treat the organic
fraction of solid waste and has the advantage of recycling many organic compounds that can be
reintroduced into the natural processes. This study aimed to provide a meta-analysis using the Life
Cycle Assessment (LCA) method to evaluate the impacts of composting by performing a systematic
literature review of the diversity of approaches and assessing environmental impacts. The results of
the impact assessment were highly dependent on the choices made over the system boundary and the
functional units. The most cited environmental impacts were GlobalWarming Potential, Acidification
Potential, Eutrophication Potential, Photochemical Oxidation Potential, and Ozone Layer Depletion,
as gaseous emissions from the transport and decomposition represent the main contributors to these
categories. Using a smaller dataset and evaluating the use of the CML method and the most cited
impacts categories, it was found that In-vessel Composting and Home Composting were considered
the best environmental options among the studied composting methods. Composting environmental
impacts were also highly related to the use of non-renewable energy sources, which puts composting
at a disadvantage when compared with the use of anaerobic digestion. Such results emphasize the
benefits of using these waste management technologies as complementary instead of substitutes.
This work received funding from COMPETE 2020—Competitiveness and Internationalization
Operational Program, Portugal 2020 and FEDER, through the project BioComp 2.0—Integrated
Approach to the Valorisation of Water Hyacinth, and the financial support of CIMO (Centro de
Investigação de Montanha) (UIDB/00690/2020) and SUSTEC (Laboratório Associado para a Sustentabilidade
e Tecnologia em Regiões de Montanha) through national funds Fundação para a Ciência
e a Tecnologia (FCT)/Ministério da Ciência, Tecnologia e Ensino Superior (MCTES).
