CET 97
DOI: 10.3303/CET2297088
Paper Received: 4 October 2022; Revised: 12 October 2022; Accepted: 13 October 2022
Please cite this article as: Lim L.Y., Bong C., Ho W.S., Lim J.S., Fan Y.V., Ong P.Y., Klemeš J.J., Lee C.T., 2022, Research Update on Food
Waste Composting: A Bibliometric Analysis and Way Forward, Chemical Engineering Transactions, 97, 523-528 DOI:10.3303/CET2297088
CHEMICAL ENGINEERING TRANSACTIONS
VOL. 97, 2022
A publication of
The Italian Association
of Chemical Engineering
Online at www.cetjournal.it
Guest Editors: Jeng Shiun Lim, Nor Alafiza Yunus, Jiří Jaromír Klemeš
Copyright © 2022, AIDIC Servizi S.r.l.
ISBN 978-88-95608-96-9; ISSN 2283-9216
Research Update on Food Waste Composting: A Bibliometric
Analysis and Way Forward
Li Yee Lima, Cassendra Bonga,†, Wai Shin Hoa, Jeng Shiun Lima, Yee Van Fanb, Pei
Ying Onga, Jiří Jaromír Klemešb, Chew Tin Leea,*
aSchool of Chemical and Energy Engineering, Universiti Teknologi Malaysia (UTM), 81310, UTM, Johor Bahru, Johor,
Malaysia
bSustainable Process Integration Laboratory – SPIL, NETME Centre, Faculty of Mechanical Engineering, Brno University of
Technology, - VUT Brno, Technická 2896/2, 616 00, Brno, Czech Republic
ctlee@utm.my
Composting is a biological process that converts organic waste into compost, an organic fertiliser. As a waste
management technology, the use of composting in managing food waste is gaining more attention these days.
In recent years, many studies have been done to analyse the research trend in solid waste management using
bibliometric analysis, which showed the potential to analyse food waste composting trends using this tool.
Bibliometric analysis is used in this study to map and visualise the food waste composting research trend
indexed in the SCOPUS database between 1987 and 2021. One thousand seven research papers were
exported from the SCOPUS database during the study period, VOSviewer and Microsoft Excel were used to
analyse the exported data. The results show that there were 1,007 publications with 31,335 citations. An
increasing trend in publication numbers was observed, especially in the recent 15 y. China, US and India are
the top 3 contributed countries in this research subject over the 34 y research period, with the US being the top
contributed country before 2000. In recent years, China has become the major contributor to food waste
composting research. Keywords analysis was done using VOSviewer, and “soil” was found to be strongly linked
to the food waste composting research, followed by “emission” and “organic matter”. The appearance of strongly
linked keywords such as “emission” and “landfill” reveals the potential environmental issues that are the major
criteria to be of concern when working on food waste composting. The presence of keywords such as “soil”,
“plant”, “application”, and “organic matter” indicates the potential of compost usage as soil amendments. An
upward trend in the publication numbers is likely to continue in the next decade. Further study on environmental
issues and compost quality might contribute to the safety and efficient use of compost in a soil application.
1. Introduction
Municipal solid waste (MSW) generation is increasing with rapid urbanisation and population growth (Xu et al.,
2021). According to World Bank (2022), the world was estimated to generate 2.24 × 109 t of MSW, equal to an
average of 0.79 kg of waste per person per day. It is expected to increase by 73 % from 2020 to reach 3.88 ×
109 t by 2025 (World Bank, 2022). The sharp increment of MSW generation is predicted to affect developing
countries mostly due to immature practices in waste management (Isibika et al., 2019). It is crucial to maximise
the bioavailability of MSW as it is considered a source of pollution and a major biomass resource (Hameed et
al., 2021).
As a biological treatment, composting is considered a more economical and safer treatment with high utilisation
value for decomposing and recycling biomass resources, especially in developing countries (Chen et al., 2021).
Composting has also been shown to reduce residual antibiotics (Zhang et al., 2018) and heavy metals
availability (Lim et al., 2018), thus enabling the safe use of materials. Mature compost without pathogen
detection can be a potential substitution for chemical fertiliser to improve soil quality and crop productivity,
maintaining soil fertility by reducing nutrient loss, suppressing soil-borne diseases and reducing water pollution
(Lim et al., 2021).
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The research on composting started in the 1930s and gradually increased until the 1990s, which has an
exponential growth until now. While the first well-recorded food waste composting article was recorded in 1987,
by Natour, about the challenges of using municipal and household refuse as composting material for crop
production and soil conservation in Kuwait (Natour, 1987). Similar to the composting research, the number of
food waste composting research has gradually increased yearly and gained more attention in recent 10 – 15 y.
The research scopes are complex due to the heterogeneity of the composting methods and inputs used. It is
essential to systematically study food waste composting research to understand the current global status and
research trends.
Bibliometric is defined as the use of statistical methods to analyse the bibliometric publications data and has
been widely used to present the relations of research domains using quantitative methods (Kulakli, 2021). It is
a useful method for identifying the research trends and coming issues and evaluating the research performance
of institutions, journals and researchers based on historic publication information (Li et al., 2018). The
publications on food waste composting research have been increasing in recent years; however, the research
trends and development directions have rarely been reviewed.
This study presents a bibliometric analysis to elucidate the research progress and trends in food waste
composting. The search was conducted in the time range from 1987 – 2021 to identify the global research
trends. Then the time range is narrowed down into four different time frames (1987 – 2001, 2002 – 2011, 2012
– 2016 and 2017 – 2021), targeting to summarise the research development, technological advancement and
current development trends for the food waste composting process. Unlike the previous review, which focused
on a certain concept or field of interest, this study focused on a broad analysis of food waste composting and
targeted to identify the missing gaps that need to be studied.
2. Methods
The SCOPUS database (www.scopus.com) was selected as the database source for bibliometric analysis.
Keyword “compost*” was searched under the categories of title, abstract and keywords, in combination with the
keyword “kitchen$waste$” OR “food$waste$” under the category of abstract. Figure 1 shows the details of the
publication selection under the SCOPUS database and the analysis performed, with the search string presented
at the top left of the figure. Excel 2019 was used to analyse the total publication and citation counts, developing
trends over countries, while VOSViewer was used for the keywords co-occurrence and research trend analysis.
Figure 1: Detailed bibliometric analytical process flow for “food waste composting” under the SCOPUS database
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3. Results and discussions
The bibliometric analysis of food waste composting is presented in this section. Figure 2 indicates the number
of publication evolution over the years, Figure 3 shows the top productive countries/territories, and Figure 4
indicates the research trends through keywords co-occurrence analysis under four different time frames: (a)
1987 – 2001, (b) 2002 – 2011, (c) 2012 – 2016 and (d) 2017 – 2021.
The first analysis was conducted to observe the total number of documents published on food waste composting.
The first document on food waste composting was in 1987. In total, 1,007 documents have been obtained
following the screening from 1987-2021. The total number of publications in the first 15 y was below 50. Since
2005, the exponential growth of document numbers has been observed (Figure 2(b)). This outcome is correlated
with the annual increase in food waste production and the urge to develop a sustainable food waste
management strategy to overcome the issue. According to UNEP (2021), about 931 Mt of food waste was
generated in 2019, with 61 % from households, 26 % from food service and 13 % from retail. The global food
waste generation is expected to grow 70 % by 2050 (UNEP, 2021).
Figure 2: (a) The annual and a cumulative number of publications in 1987 – 2021, (b) the exponential trendline
of publications number in 2000 – 2021.
Figure 3 shows the contribution of the top productive countries/territories in food waste composting. China and
the USA have similar document numbers in the research area. Comparing the research progress, China
surpassed the USA in 2013 with the fastest growth rate from 2013 to 2021. India and Malaysia have also
achieved a faster growth rate since 2015. The reason for these phenomena was that developed countries started
with a relatively better management system much earlier in the research area. Thus, a more stable research
trend was observed in developed countries. For China and other developing countries experiencing rapid
industrialisation and urbanisation, MSW production has become a major challenge. According to Li et al. (2018),
China has become the largest MSW generator since 2004, and USD 2.1 x 1011 was invested in solid waste
disposal projects from 2006 - 2010. In 2000, China was recorded to dispose of 118.2 Mt of garbage. A sharp
increment (32 %) in garbage disposal was observed until 2005, followed by a 1 – 7 % yearly increment, reaching
242.06 Mt garbage disposal in 2019 (Statista, 2022). Similar to Malaysia, rapid food waste production in
Malaysia also experienced dramatic growth over these years. Food waste production in Malaysia was also
observed to increase from 465 t·d-1 to 15 kt·d-1 from 2009 to 2013 and further increased to 17,007 t·d-1 in 2021
(Yuen, 2022). A dropping trend was observed in the years 2019 and 2020 for most countries, which can be
greatly related to the COVID-19 pandemic. According to Pappalaardo et al. (2020), during the pandemic
lockdown, food waste decreased even though there was an increased amount of food purchases. Burlea-
Schiopoiu et al., (2021) also observed more people exhibiting food waste reduction behaviour after the
pandemic. Besides, the pandemic lockdown also affected the research progress. The research project might be
suspended due to the movement control or insufficient food waste to run the composting research. The drift of
research interest toward COVID-19-related topics might be another reason for the dropping trends observed.
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Figure 3: Top 10 productive countries/territories and the top 5 productive countries/territories' development
trends in food waste composting
The keywords co-occurrence analysis was done using VOSViewer under four different time frames with the
significant research trends under different time frames and the corresponding publication numbers bracketed in
Figure 4. The research on food waste composting has a relatively slow development in the first time frame (1987
– 2001). Only 48 articles were observed that focused more on the potential of using composting in solving the
problems due to increased food waste production. From 2002 – 2011 where significant food waste generation
was observed, more focus was put on developing a better system and the potential use of the mature compost.
As food waste is high in N contents and low in bulk density, green and wood wastes with high C content and
bulk density were introduced as co-composting materials to improve the process succession rate.
From 2012 – 2016, more mature technology was developed with detailed analyses, such as elemental analysis
and maturity and stability test, the research aimed to understand further the composting process. Comparisons
of waste management technologies became a major trend by comparing the potential rewards and costs and
process emissions between technologies to ease the selection. From 2017 – 2021, the research trend involved
a combination of previous research. Cluster 1 (Red) indicates the issues related to food waste, the related
management strategies, and their respective environmental impacts and cost benefits. Cluster 2 (Green)
indicates the composting process and the analyses, and the respective amendments made to improve the
process. Cluster 3 (Blue) is mainly on compost application and the comparison of the relative effects, such as
plant growth and soil quality improvement, with other organic materials inputs.
When looking at the top 10 cited articles under food waste composting in recent 5 y, inoculation of composting
piles with either black soldier fly or bacterial inoculant accounted for 64 % of the total citation. Especially for the
inoculation with black soldier flies, it has become a very hot topic in recent years, with the increasing argument
on the roles of composting in waste management under the development of other treatment approaches,
particularly anaerobic digestion, which enables cascade utilisation where extraction (waste to chemical) or
conversion could be done before and after. The digestate could be utilised for other purposes or returned later
to the soil, and the GHG savings potential is higher than composting. The inoculation of black soldier fly larvae
can shed light on food waste composting research. During the process, the food waste is converted not only to
compost but also to dry larvae, which can be used as animal feed. Black soldier fly larvae are found to be
versatile in their feedstock preferences and can be used to treat a variety of organic waste streams, provided
that the total volatile solids and nitrogen content are sufficiently high to support larval development (Lalander et
al., 2019). Although the life cycle assessment on this does not seem to give a very promising outcome due to
the drying process that requires high energy input, the replacement of the chemical fertiliser with compost and
the replacement of animal feed or diesel production feedstock with dried larvae might give some improvement
on it. As it is a quite new topic in this research area, more research is needed to investigate the pros and cons-
of the inoculation of black soldier fly larvae in terms of life cycle assessment and process improvement.
The abovementioned research shows that an exponential upward trend in food waste composting research will
likely continue in the next few decades. The following topics are predicated as the hot issues in the near future:
(i) The environmental impact and cost benefits of food waste composting and the potential of achieving a circular
economy between food waste, compost product and soil system; (ii) the improvement of the final food waste
compost quality for the safety and efficient used as a soil fertiliser; (iii) the potential of food waste composting to
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achieve cascade utilisation. The future hot topics and issues were predicted by looking into the food waste
composting research development and comparing them with the developing trend of those well-developed
technologies (especially AD, as a biological treatment that shares the same feedstocks, it is essential to figure
out the benefits of composting over AD). The future trends are also predicted by looking at the development of
the recent hot topic related to the composting field (e.g. circular economy). The last but not least, the unfilled
gaps in composting research (e.g. the potential improvement in compost application).
Figure 4: Clustering of the keywords co-occurrence analysis over the plain text of 1,007 publications. Tables at
right listing the total link strength of the major keywords for different time frame analysis.
4. Conclusions
In conclusion, food waste composting is still under its exponential growth with the rapid increment of food waste
production yearly. An advancement of mature technology for food waste composting has been developed over
40 y of research. Recent research trends have focused on the environmental impact and cost-benefit of the
process and the potential of the compost product being used as a soil fertiliser. The safety and precision
application of food waste compost to promote plant growth and soil fertility will continue to be a hot research
topic in the next few decades. A comprehensive comparison between composting and other alternatives from
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different perspectives (economically, environmentally, socially) and scale based on different circumstances have
to be assessed and optimised.
Acknowledgements
The authors wish to thank Universiti Teknologi Malaysia for supporting this work. This work was supported by
the Ministry of Science, Technology and Innovation under the research grant R.J130000.7951.4S150 and the
Ministry of Higher Education under the Fundamental Research Grant Scheme
(FRGS/1/2019/STG05/UTM/02/9).
References
Burlea-Schiopoiu A., Ogarcă R.F., Barbu C.M., Craciun L.,Baloi I.C., Mihai L.S., 2021, The impact of COVID-19
pandemic on food waste behaviour of young people, Journal of Cleaner Production, 294, 126333.
Chen X., Cheng W., Li S., Tang X., Wei Z., 2021, The “quality” and “quantity” of microbial species drive the
degradation of cellulose during composting, Bioresource Technology, 320, 124425.
Hameed Z., Aslam M., Khan Z., Maqsood K., Atabani A.E., Ghauri M., Khurram M.S., Rehan M., Nizami A.-S.,
2021, Gasification of municipal solid waste blends with biomass for energy production and resources
recovery: Current status, hybrid technologies and innovative prospects, Renewable and Sustainable Energy
Reviews, 136, 110375.
Isibika A., Vinnerås B., Kibazohi O., Zurbrügg C., Lalander C., 2019, Pre-treatment of banana peel to improve
composting by black soldier fly (Hermetia illucens (L.), Diptera: Stratiomyidae) larvae, Waste Management,
100, 151-160.
Kulakli A., 2021, Integration of Data Mining and Business Intelligence in Big Data Analytics: A Research Agenda
on Scholarly Publications, Chapter in: Azevedo A. (Ed.), Integration Challenges for Analytics, Business
Intelligence, and Data Mining, IGI Global, USA, 13-43.
Lalander C., Diener S., Zurbrügg C., Vinnerås B., 2019, Effects of feedstock on larval development and process
efficiency in waste treatment with black soldier fly (Hermetia illucens), Journal of Cleaner Production, 208,
211-219.
Li N., Han R., Lu X., 2018, Bibliometric analysis of research trends on solid waste reuse and recycling during
1992–2016, Resources, Conservation & Recycling, 130, 109-117.
Lim L.Y., Lee C.T., Bong C.P.C., Lim J.S., Ong P.Y., Klemes J.J., 2021, Selection of parameters for soil quality
following compost application: A ranking method, Chemical Engineering Transaction, 83, 505-510.
Lim L.Y., Lee C.T., Bong C.P.C., Lim J.S., Roji Sarmidi M., Klemes J.J., 2018, A review on the impacts of
compost on soil nitrogen dynamics, Chemical Engineering Transactions, 63, 349-354.
Natour R.M., 1987, Utilization of municipal compost in Kuwait, Dirasat, 14, 95-106.
Pappalardo G., Cerroni S., Nayga R. M., Yang W., 2020, Impact of Covid-19 on Household Food Waste: The
Case of Italy, Frontiers in Nutrition, DOI: 10.3389/fnut.2020.585090.
Statista, 2022, Amount of disposed garbage in China from 1990 to 2020 (in million tons)
accessed 30.08.2022.
Salomone R., Saija G., Mondello G., Giannetto A., Fasulo S., Savastano D., 2017, Environmental impact of food
waste bioconversion by insects: Application of Life Cycle Assessment to process using Hermetia illucens,
Journal of Cleaner Production, 140, 890-905.
United Nations Environment Programme (UNEP), 2021, Food Waste Index Report 2021, UNEP, Nairobi.
World Bank, 2018, What a Waste 2.0: A Global Snapshot of Solid Waste Management to 2050, Washington,
DC, USA.
World Bank, 2022, Solid Waste Management accessed 30.08.2022.
Xu M., Yang M., Xie D., Ni J., Meng J., Wang Q., Gao M., Wu C., 2021, Research trend analysis of composting
based on Web of Science database, Environmental Science and Pollution Research, 28, 59528-59541.
Yuen M., 2022, M’sians continue to waste food, TheStar accessed 30.08.2022.
Zhang B., Wang M.M., Wang B., Xin Y., Gao J., Liu H., 2018, The effects of bio-available copper on macrolide
antibiotic resistance genes and mobile elements during tylosin fermentation dregs co-composting,
Bioresource Technology, 251, 230-237.
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Research Update on Food Waste Composting: A Bibliometric Analysis and Way Forward