# Vermicomposting of municipal solid waste as a possible lever for the development of sustainable agriculture. A review

Vincent Ducasse, Yvan Capowiez, Josephine Peigné

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Vincent Ducasse, Yvan Capowiez, Josephine Peigné. Vermicomposting of municipal solid waste as a possible lever for the development of sustainable agriculture. A review. Agronomy for Sustainable Development, 2022, 42 (5), pp.1-40. 10.1007/s13593-022-00819-y. hal-03836461

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Vermicomposting of municipal solid waste as a possible lever for the
development of sustainable agriculture – a review

3

4

Vincent Ducasse<sup>a,b*</sup> ; Yvan Capowiez<sup>a</sup> ; Joséphine Peigné<sup>b</sup>

5ª INRAE, EMMAH, UMR 1114 INRAE-Avignon University, Domaine Saint Paul, F-84914 Avignon
6cedex 09, France

7ᵇ Department of Agroecology and Environment, ISARA (member of the University of Lyon), 23 rue 8Jean Baldassini, 69364, Lyon cedex 07, France

9* Corresponding author: vducasse@isara.fr

10 Abstract:

11Continued population growth and urbanization as well as changing consumption patterns have led to
12an explosion in the amount of waste produced, especially in cities. To feed the world, we also need to
13increase agricultural production while limiting our impact on the environment. Part of the solution
14could be to recycle the organic fraction of municipal solid waste (OFMSW) as a resource for
15agriculture near cities with techniques such as vermicomposting, which uses earthworms to recycle
16organic waste into nutrient-rich vermicompost. The objective of this review was to examine (i)
17whether vermicomposting is appropriate for recycling OFMSW, (ii) the quality of the vermicompost
18produced, and (iii) the impact of this product on crops and soil parameters. We found that
19vermicomposting can be adapted for OFMSW recovery because the process is suitable for all the types
20of OFMSW (food, paper, and green waste). The vermicompost produced is both high in organic
21carbon (18.83% to 36.01%) and a potential fertilizer (1.16 to 2.58% N, 0.42% to 1.12% P and 0.61%
22to 2.05% K). A comparison with compost from the same types of OFMSW suggested that
23vermicompost is slightly more suitable for crop production with significantly lower C/N and pH and
24higher N and P. Vermicompost was actually found to have a better effect on plant growth than
25compost, suggesting that classical chemical analyses are not always sufficient to characterize the
26potential of organic amendments/fertilizers. Indeed, the application of vermicompost in the field leads
27to an increase in carbon storage, water retention, enzymatic and microbiological activity, and soil
28fauna abundance and diversity. Finally, we found that reports on the use of vermicompost from
29OFMSW are scarce and most studies focused on the process itself. Overall, our review synthesizes
30data and the interest in this technique and proposes perspectives for future studies.

31

32

33**Keywords:** Vermicompost – Waste management – Organic Fraction of Municipal Solid Waste –
34Agronomical impact – Soil conservation
36Table of contents:

37

<table><tr><td>381</td><td>Introduction</td><td>3</td></tr><tr><td>392</td><td>Material and methods</td><td>6</td></tr><tr><td>40</td><td>2.1 Literature search</td><td>6</td></tr><tr><td>41</td><td>2.2 Data selection</td><td>6</td></tr><tr><td>42</td><td>2.3 Data treatment</td><td>6</td></tr><tr><td>433</td><td>Results and discussion</td><td>9</td></tr><tr><td>44</td><td>3.1 Suitability of vermicomposting for OFMSW recovery in urban environments</td><td>9</td></tr><tr><td>45</td><td>3.1.1 Study Typology</td><td>9</td></tr><tr><td>46</td><td>3.1.2 High diversity in OFMSW categories</td><td>10</td></tr><tr><td>47</td><td>3.2. Quality of vermicompost from OFMSW</td><td>13</td></tr><tr><td>48</td><td>3.2.1 Variability of vermicompost between studies</td><td>14</td></tr><tr><td>49</td><td>3.2.2 Comparison of the quality of vermicompost and compost from the same OFMSW</td><td>16</td></tr><tr><td>50</td><td>3.3 Benefits and limitations of using vermicompost from OFMSW in agriculture soils</td><td>17</td></tr><tr><td>51</td><td>3.3.1 Effects on crop yield</td><td>17</td></tr><tr><td>52</td><td>3.3.2 Effects in soil (bio-physico-chemical)</td><td>19</td></tr><tr><td>534</td><td>Outlook and future studies</td><td>20</td></tr><tr><td>54</td><td>4.1 Studies on the process of vermicomposting using OFMSW</td><td>20</td></tr><tr><td>55</td><td>4.2 Use of vermicompost from OFMSW in the field</td><td>20</td></tr><tr><td>56</td><td>4.3 Comparison with other techniques and integration into OFMSW management systems</td><td>21</td></tr><tr><td>57</td><td>4.4. Socio-economic issues</td><td>22</td></tr><tr><td>585</td><td>Conclusions</td><td>23</td></tr><tr><td>596</td><td>Bibliography</td><td>24</td></tr></table>

60
61"Figure 1": Picture of vermicomposting windrow of urban organic waste (food) and cattle manure.

<figure><img src="image_2.png" /></figure>

62

63

641 Introduction

65

66In the past farmers used organic waste from cities to amend soils but with the development of the
67chemical and food industry in the 20th century this waste was no longer of interest (Barles 2014). The
68link between urban organic waste and agriculture has thus largely been forgotten as a result of the
69intensification of agriculture and urbanization. Indeed, agricultural practices have become increasingly
70standardized with, for example, the use of nitrogen-phosphate-potassium (N-P-K) fertilizers
71(Kibblewhite et al. 2008). Farm specialization has also led to activities being distributed according to
72sector and region. Martin et al., (2018) noted that animal waste such as manure is concentrated in
73certain regions of the world, which can lead to potential pollution, while other agricultural areas lack
74organic matter (OM) to feed their soils. Cities are generally surrounded by "agricultural belts", which
75should make it possible to promote the valorization of the organic fraction of municipal solid waste
76(OFMSW).

77

78A World Bank study (Bhada-Tata and Hoornweg 2012), predicted that municipal solid waste will
79increase by 70% between 2012 and 2025 to reach 2.2 billion tons per year. Twenty to 30% of this
80waste is organic waste, with up to 80% of it coming from low- and middle-income regions
81(Troschinetz and Mihelcic 2009). Organic waste recovery from cities represents an enormous
82challenge for circular waste management, which aims to return OM to the soil to "close the loop" and
83thus save natural resources and reduce our impact on the environment (Ghisellini et al. 2016). To
84manage organic waste from cities in a sustainable way, it is necessary to divert it from classical
85management and treatment methods such as incineration and/or landfill. Bortolotti et al., (2018)
86showed that decentralized management of urban organic waste is a promising alternative to centralized
87industrial facilities. There are many techniques for recovering organic waste that can be adapted at
88different scales, converting it into a valuable resource. In their review, Lohri et al., (2017) classified
89these into four different categories: (i) direct use (direct land application, direct animal feed or direct
90combustion), (ii) biological treatment (composting, vermicomposting, black soldier fly treatment,
91anaerobic digestion, fermentation), (iii) physico-chemical treatment (transesterification, densification)
92and (iv) thermo-chemical treatment (pyrolysis, liquefaction, gasification). Among the products
93produced from these methods, compost (from composting and vermicomposting), black soldier fly
94residues, anaerobic digestate and biochar from pyrolysis can be used in agriculture (Lohri et al. 2017).

95

96Vermicomposting is a controlled OM degradation process based on the addition of earthworms
97upstream of decomposition to accelerate the stabilization process (Dominguez 2004; Munroe 2007;
98Lim et al. 2016). The main objective is to stabilize and degrade OM to produce a humus-like material,
99called vermicompost (Adhikary 2012; Doan et al. 2015). The degradation process is carried out at
100room temperature (mesophilic process) and stabilization is achieved through the interaction of
101earthworms, associated microorganisms and other decomposers (Gomez-Brandon et al. 2012). To
102avoid compaction and control aeration, a minimum of 2.5 kg of earthworms per m² (Munroe 2007)
103should be maintained in piles that are smaller than those for composting (1m maximum). If these
104conditions are respected, there is no need to turn the heap and the environment is conducive to
105earthworms and does not heat. The earthworm species used are generally epigeic (Blouin et al., 2013),
106which naturally remain on the soil surface and in the fresh bedding used as food. Eisenia fetida,
107(Savigny 1826) (Haplotaxida, Lumbricidae) is the most widely used species in vermicomposting due
108to its high waste ingestion capacity (Edwards et al. 2010). Although many variations in
109vermicomposting techniques have been developed, from low tech in windrows to high tech with fully
110automated continuous-flow vermicomposting reactor systems, (Board 2004; Edwards et al. 2010),
111there are always two major phases in the process: (i) the active decomposition phase and (ii) the
112maturation phase, (Munroe 2007; Sim and Wu 2010; Ali et al. 2015). In the active decomposition
113phase (i) earthworms (a) ingest, digest and cast organic matter; they not only improve the assimilation
114of OM (indirect effect) but also facilitate the movement of poorly mobile microorganism communities
115(direct effect) (Monroy et al. 2008); and (b) the fractionate OM. They thus allow an increase in the
116potential surface area exposed to other decomposers, especially microorganisms (Aira et al. 2007;
117Gomez-Brandon et al. 2012). Logistically, this first phase consists of setting up earthworm litter
118adapted to the quantity of waste to be recovered before applying the OM in a discontinuous (one-time
119application) or continuous (regular applications) way. Batch feeding requires more work but allows better control of the earthworm environment as well as pH and humidity control. To adjust these factors, bulking agents such as cardboard boxes, waste from green spaces or straw (for manure) are used. In the maturation phase (ii) earthworms migrate to new layers of fresh and undigested waste. Fresh OM is added in contact with the almost decomposed OM so that the hungry earthworms migrate to the new fresh litter. This step is essential to keep as many earthworms as possible and continue the process while harvesting the resulting earthworm-free vermicompost.

126

127Most of the studies on vermicomposting processes focused on adding value to animal manure and some rare reviews highlighted the potential of this technique for the valorization of urban organic waste (Sim and Wu 2010; Singh et al. 2011). In their recent review, Alshehrei and Ameen (2021) highlighted a growing interest in vermicomposting for the valorization of Municipal Solid Waste (MSW) in urban environments, particularly the organic fraction (OFMSW). Recently, the regulations concerning the recovery of OFMSW have been evolving with, for example, a new European mandate to consider this waste as an amendment resource by the end of 2023 (European Union 2018). Thus, it is necessary to find processes with the lowest impact on the environment but adapted to urban environments and all the related constraints (high density, pollution and so on...).

136

137Few studies have evaluated the agronomic potential of vermicomposts from OFMSW. However, studies concerning the use of vermicomposts from manures in agriculture show encouraging results for plant growth (Atiyeh et al. 2000; Jouquet et al. 2011), the development of beneficial bacteria for plants (Monroy et al. 2008; Aira et al. 2008; Adhikary 2012) and a reduction in plant diseases and pest attacks (Ersahin 2010; Cardoza 2011; Rowen et al. 2019). Once applied and incorporated into the soil, it decreases bulk density and increases porosity, increases water retention capacity and promotes aeration (Manivannan et al. 2009; Lim et al. 2014). In addition, a meta-analysis showed that the addition of vermicompost from manure increases crop yield and total biomass (Blouin et al. 2019). There is therefore a strong need to know more about vermicompost from OFMSW, to see if this product could have the same benefits to soil and crops, and thus help recycle OM (from the city to the field and vice versa).

148

149In this review, we first (i) define and classify the studies on vermicomposting of OFMSWs as a function of waste category and various other factors. Then, we characterize more precisely (ii) the quality of the vermicompost resulting from OFMSW to determine whether this product has interesting potential for the development of agriculture compared to classic compost. Finally, we evaluate (iii) the impact of this product on crops and the bio-physico-chemical parameters of the soil once applied to the field. We then discuss the outlook and future research perspectives and studies needed to better understand this process and its applications.
156

157

1582 **Material and methods**

159

1602.1 *Literature search*

161

162The Web Of Science (Clarivate©) was first searched for publications from 2000 to 2020 using the
163following keywords: "vermicompost*" OR "vermiculture" OR "vermitechnology". This search
164recovered a set of 3128 articles. To refine the search we then added the following keywords: AND
165"organic waste" OR "municipal solid waste" OR "urban food waste" OR "urban solid biowaste" OR
166"biowaste" OR "urban waste" OR "urban biowaste" OR "vegetable waste" OR "food waste". This
167refined search recovered 410 articles (last search on 23/10/2020). We performed the same search on
168the CABI database (CAB direct) to access national journals that often provide analysis of products
169such as vermicompost and obtained 724 articles in total. We then read the abstracts and selected those
170articles really focusing on OFMSW recycling. Here we defined OFMSW as biodegradable urban
171organic waste including non-liquid waste (thus excluding sludge) from households and small
172businesses and institutions as defined by Wilson et al., (2015). We finally obtained 96 original papers
173and 19 reviews from the Web Of Science (Clarivate(c)) and 88 additional papers and three additional
174reviews from the CABI database, for a total of 184 papers and 22 reviews. To examine how prevalent
175research on vermicomposting of OFMSW is compared to the other techniques of OFMSW recovery
176we also carried out a search with the same keywords in the Web Of Science (Clarivate(c)) and
177obtained 4,916 results with "compost*", 692 results with "methanisation" OR "digestate" and 163
178results with "black soldier fly".

179

1802.2 *Data selection*

181

182To characterize vermicomposting processes and vermicompost quality and applications we recorded
183specific information from the papers (Table 1). First, we identified the (i) categories of OFMSW in
184each study. Since we found a wide variety of organic waste (sometimes different names for the same
185waste), we chose to group it into categories: food, green waste, paper, and MSW (undefined mixture
186of municipal organic waste). Then we noted the (ii) species of earthworm used for the process and we
187found out if (iii) a pre-treatment was carried out before the process. We also noted for each of the
188studies if it was carried out in (iv) the laboratory or in the field and if it concerned the (v) process itself
189or the use of the vermicompost. Finally, we identified the (vi) country where the studies and
190experiments took place (grouped by continent) to identify the locations that are most interested in this
191process.

192
195To examine the quality of the vermicompost resulting from OFMSW and determine whether this
196product has interesting potential for the development of agriculture compared to classic compost
197produced from OFMSW, we recorded data from each article/paper for the agronomically-important
198and metallic trace elements to calculate a mean and obtain a standard error according to factors. After
199analyzing the intra variability (different vermicomposts) we selected the studies that compared
200vermicomposts to composts from the same OFMSW to estimate its quality relative to a better-known
201product and we used paired tests. All analyses, tables and calculations were performed using RStudio
202software (version 1.4.17.17).
203**Table 1:** Information retrieved from the 184 articles according to the factors studied: (i) urban organic waste categories, (ii) earthworm species, (iii) pre-treatment, (iv) laboratory (including greenhouse) or field experiment, (v) vermicomposting process or vermicompost use study and (vi) continent. In urban organic waste categories the factor "food" includes "households waste", "kitchen waste", "food waste", "vegetable waste", "supermarket food waste", 206"coffee" and "fruit waste"; the factor "green waste" includes "tree leaves", "garden residues", "sawdust", "shaving", "wood", "urban green waste", "turf 207grass" and "urban aquatic seed"; the factor "paper" includes "paper", "newspaper" and "cardboard" and the factor "MSW" includes "municipal solid waste", 208"solid urban waste", "organic part of MSW". MSW was divided into food, green waste and paper where possible according to the author's description and the 209replication of the same mixture with different ratios in the same publication was only counted once. In earthworm species the factor "unspecified species" 210indicates that in the publication the earthworm species was not specified or defined at the species level. In pre-treatment the factor "stabilization" indicates 211that the waste was left out in the open without treatment (usually to stabilize the temperature); the factor "cut" indicates that the waste was shredded before the 212processes and the factor "dry" indicates that the waste was dried before the processes.

<table><thead><tr><th>Factor studied</th><th>(i) Urban organic waste categories</th><th>(ii) Earthworm species</th><th>(iii) Pre-treatment</th><th>(iv) Laboratory (including greenhouse) or field experiment</th><th>(v) Vermicomposting process or vermicompost use study</th><th>(vi) Continent</th></tr></thead><tbody><tr><td rowspan="2">Factor identified and its occurrence (x)</td><td>Food (150)</td><td><i>Eisenia fetida</i> (116)</td><td>Absent or undefined (80)</td><td>Laboratory (160)</td><td>Process (125)</td><td>Asia (117)</td></tr><tr><td>Green waste (64)</td><td><i>Eudrilus eugenia</i> (31)</td><td>Composting (62)</td><td>Field (20)</td><td>Use (44)</td><td>America (37)</td></tr><tr><td rowspan="2"></td><td>MSW (57)</td><td>Unspecified species (28)</td><td>Stabilization (34)</td><td>Laboratory and field (4)</td><td>Process and use (15)</td><td>Europe (14)</td></tr><tr><td>Paper (46)</td><td><i>Perionyx excavatus</i> (13)<br><i>Eisenia andrei</i> (10)<br><i>Lampito mauritii</i> (10)<br><i>Lumbricus rubellus</i> (5)<br><i>Metaphire posthuma</i> (2)<br><i>Perionyx sansibaricus</i> (3)<br><i>Perionyx ceylanensis</i> (1)<br><i>Pheretima peguana</i> (1)<br><i>Allolobophora parva</i> (1)<br><i>Amynthus diffringens</i> (1)<br><i>Metaphire houlieti</i> (1)<br><i>Octolasion tyrtaeum</i> (1)<br><i>Dendrobaena veneta</i> (1)<br><i>Octochaetha thurstoni</i> (1)<br><i>Octochaetona serrata</i> (1)<br><i>Lumbricus terrestris</i> (1)</td><td>Cut (33)<br>Dry (12)<br>Mix (9)</td><td></td><td></td><td></td><td>Africa (14)<br>Oceania (2)</td></tr><tr><td>Total repetition of factor (n)</td><td>n = 317 because some studies used several mixtures for their experiment</td><td>n = 228 because some studies used several species for their experiments</td><td>n = 230 because some studies used several techniques of pre-treatment</td><td>n = 184</td><td>n = 184</td><td>n = 184</td></tr></tbody></table>
2133 Results and discussion

214

2153.1 Suitability of vermicomposting for OFMSW recovery in urban environments

216

2173.1.1 Study Typology

218

219Our literature review found that vermicomposting is less studied than other OFMSW recovery processes. For example, reports on classical composting were published 10 times more frequently than vermicomposting (410 results) during the same period on the Web Of Science (4,916 results). The geographical origin of the studies on vermicomposting shows that it was mostly studied in Asia (63.6%), moderately in America (20.1%) and less in Europe (7.6%), Africa (7.6%) and Oceania (1.1%) (Table 1). Studies on the vermicomposting of OFMSW were still largely carried out in the laboratory (87%). Only 10.9% were carried out in the field and only 2.1% in both the laboratory and field. In addition, 67.9% of the studies focused on the vermicomposting process itself, 23.9% on the use of vermicompost from OFMSW and 8.2% on both (process and use). This suggests that vermicomposting is not thoroughly studied in outdoor conditions and that most of the studies focused on the understanding or optimization of the process. When the two parameters were crosschecked, this further confirmed that most of the research on vermicomposting is done in the laboratory and about processes (65.2%). Moreover, even the application of vermicompost is studied more in the laboratory (laboratory and use = 16.3%) than in the field (field and use = 7.1%). These trends can explain why this technique is not widely used to valorize OFMSW on a global scale. This also raises the question of whether the vermicomposting process, which is well known for waste such as manure, is more difficult to use on OFMSW due to the high variability of this waste, suggesting that further fundamental laboratory studies are required.

237

238As earthworms are fundamental to this process, we recorded the earthworm species used and their frequency in the articles (Table 1). As expected, *E. fetida* was the most studied species and was found in 50.9% of experiments. The second most used species was *Eudrilus eugenia* (13.6%) followed by *Perionyx excavates* (5.7%). In a relatively high percentage of studies the species was not specified (12.3%). This was generally in papers that only investigated the application of vermicompost. Other less common species were also used in Asia such as *Lampito mauritii*, which is an anecic species (Tripathi and Bhardwaj 2004) and *Metaphire posthuma*, which is an endogeic species (Doan et al. 2013). It is important to note that earthworm ecological categories were defined on European species (Bouché, 1977) and it is difficult to use these categories for non-Lumbricidae species (Asian for example) while the concept itself remains controversial (Bottinelli et al. 2020). Studies that compared the effectiveness of different earthworm species on the decomposition of organic waste suggest that *E. fetida* more rapidly transforms OM into vermicompost (Kaviraj and Sharma 2003; Tripathi and Bhardwaj 2004; Rajpal et al. 2012). Other species are used because in some parts of the world *E*.
251*fetida* is not naturally present and thus some studies focused on the potential of native and readily 252available species (Suthar 2007, 2009; Soobhany et al. 2015a). This type of research on potential 253earthworm species for vermicomposting also highlights the need for fundamental laboratory studies.

254

2553.1.2 *High diversity in OFMSW categories*

256

257The information found in the 184 articles (Table 1) showed that about half of the studies concerning 258the recovery of OFMSW were based on food waste (47.3%). However, Table 1 only counts the 259occurrence of the four keywords in the articles (food, green waste, paper and MSW) but not if the 260studies recycled these different materials in a mixture. To define the quality of vermicompost from this 261particular type of waste, we first listed the different types of urban waste that have been 262vermicomposted in the 184-article dataset (Table 2). We found 256 different types of mixtures that we 263grouped into two major groups: (i) urban waste only and (ii) urban waste + other waste. The exact 264name of the waste (not the typology used here) and the proportion used in each study are listed in the 265annex table 1. This classification showed that almost half of the mixtures studied (Table 2: 43.75%) 266also contained other materials besides urban waste (OFMSW) such as agricultural waste (manure, 267which is the preferred substrate for vermicomposting). However, vermicomposting of OFMSW is also 268possible with green waste (Tognetti et al. 2008; Wani et al. 2013) or shredded paper and cardboard 269(Hanc and Pliva 2013; Soobhany et al. 2015b; Mathivanan et al. 2017), which is an abundant resource 270in cities. According to Hogg et al., (2002), paper and cardboard represent up to 37% of MSW and 271food waste added to green waste represents up to 53% of MSW in different European countries. All 272these wastes, which make up the majority of MSW, can be recovered through vermicomposting, which 273would avoid having to resort to other wastes that are not necessarily easily accessible in urban areas, 274such as agricultural wastes. OFMSW mainly includes isolated waste (food, green waste or paper only) 275and not mixtures of several types: 43% of the studies concerned food leftovers, 9% green waste and 2768% paper, which represented a total of 60% of the studies compared with 40% dealing with mixtures 277of several classes (MSW are included). For the process of vermicomposting OFMSW, it is usually 278necessary to mix different wastes such as food waste with a bulking agent such as cardboard and/or 279paper and/or shredded wood. Studies without the use of a bulking agent were all carried out in the 280laboratory, whereas outdoor studies (only 10/140 studies of the process) described the process with 281mixed waste (green waste, paper with food and MSW which is a mix of organic municipal waste) 282because they were adapted to the field reality and the constraints of the process (Singh and Sharma 2832003; Mishra et al. 2005; Pattnaik and Reddy 2010, 2011; Agarwal and Arora 2011; Abdrabbo et al. 2842014; Cao et al. 2016; Hanc et al. 2017; Hrebeckova et al. 2019; Dohaish 2020).
285Table 2: Classification of the 256 waste mixtures found in the 184 articles. In urban organic waste + other waste category the factor “agricultural waste”
286includes “hay”, “straw”, “rice bran”, “sugarcane bagasse”, “biogas slurry from agriculture”, and all animal slurry, dung and manure, the factor “sewage
287residues” includes “sewage sludge” and “biosolids”.

288

<table><thead><tr><th>Factor studied</th><th>Urban organic waste only</th><th>Urban organic waste + other waste</th><th>Other type of material used for the process (with the ratio used)</th></tr></thead><tbody><tr><td rowspan="10">Type of waste mixed with OFMSW and its occurrence (x)</td><td>Food (63)</td><td>Food + agricultural waste (45)</td><td>Products:<br>Biochar (2) – 10% maximum</td></tr><tr><td>MSW (29)</td><td>Green waste + agricultural waste (16)</td><td>Red mud (1) – 15 %</td></tr><tr><td>Green waste (13)</td><td>MSW + agricultural waste (14)</td><td>Ash (1) – 15 %</td></tr><tr><td>Paper (12)</td><td>Food + green waste + agricultural waste (9)</td><td>Zeolite (1) – 10% maximum</td></tr><tr><td>Food + green waste + paper (9)</td><td>Food + paper + agricultural waste (7)</td><td>Urea (1) – to adjust C/N ratio</td></tr><tr><td>Food + paper (8)</td><td>Paper + agriculture waste (5)</td><td>Lime (1) - 5 g CaCO3/kg</td></tr><tr><td>MSW + green waste (6)</td><td>Food + green waste + paper + agricultural waste (4)</td><td>Mussorie rock phosphate (1)</td></tr><tr><td>Food + green waste (4)</td><td>Paper + green waste + agricultural waste (1)</td><td>Saw dust (1)</td></tr><tr><td></td><td>MSW + sewage residues (6)</td><td>Dry neem (1)</td></tr><tr><td></td><td>MSW + agricultural waste + sewage residues (2)</td><td>Nutrient (iron, manganese, zin, copper, molybdenum, boron) (1)</td></tr><tr><td></td><td>Green waste + sewage residues (2)</td><td>Butter milk Jaggery (1)</td></tr><tr><td></td><td>Food + sewage residues (1)</td><td>Vermiwash (1)</td></tr><tr><td rowspan="4">Total repetition of factor (n)</td><td rowspan="4">n = 144</td><td rowspan="4">n = 112 with agricultural waste (n = 101); sewage residues (n = 11)</td><td>Microbial inoculants:<br>T. viridae, B. polymyxa and P. crysoporium - 50 ml/kg (1)</td></tr><tr><td>Trichoderma harzianum (1)</td></tr><tr><td>Leucaena leucocephala and Morus alba. Penicillium funiculosum and P. chrysogenum (1)</td></tr><tr><td>Pleurotus sajor-caju (fungus), Trichoderma harzianum (fungus) and Azotobacter chroococcum (1)</td></tr><tr><td></td><td></td><td>Owinema: larvae of the nematode Steinernema feltiae - 50 . 10<sup>6</sup> larvae m<sup>-2</sup> (1)</td></tr><tr><td></td><td></td><td>n = 18</td></tr></tbody></table>
2893.1.3 Advantages and limitations of the vermicomposting process with OFMSW in an urban context

290

291OFMSW valorization requires adapted processes that take into account the environmental stakes and 292adapt technically to an urban context. Thus in this section, we discuss the advantages (speed, reduced 293GHG, lack of odor, adaptability to different spatial scales) and disadvantages (some wastes require 294more complex pre-treatments) of vermicomposting OFMSW according to the present review of the 295subject.

296

297Ammonia ($NH_3$), methane ($CH_4$) and nitrous oxide $N_2O$ emissions from vermicomposting are up to 298three times lower than for domestic composting (Lleo et al. 2013). Indeed, Komakech et al., (2015) 299showed with a life cycle analysis (LCA) of city biodegradable waste treatment systems that 300conventional composting (thermophilic) emitted 80.9 kg $CO_2$ eq.ton$^{-1}$ of waste compared to 17.7 for 301vermicomposting, i.e. 78% less GHG. This is mainly due to the heat produced during traditional 302composting, which produces a significant amount of GHG as 25 to 36% more $N_2O$ and 22 to 26% 303more $CH_4$ than vermicomposting (Nigussie et al. 2016). Nigussie et al. (2016) showed that by 304increasing the earthworm density (1kg and 3kg per m$^2$) and moisture content (75% and 85%) during 305the process, it was possible to further reduce GHG emissions (decreased $N_2O$ emissions by 40% and 30623% and $CH_4$ emissions by 32% and 16%, with higher and lower moisture contents, respectively and 307decreased $CH_4$ emissions by 35% and 10% with higher and lower earthworm density, respectively 308while this density has no effect on $N_2O$ emissions) and significantly reduced N loss by 10–20% 309compared to thermophilic composting. Based on the study by Bernstad Saraiva Schott et al. (2016), 310Nigussie et al. (2016) excluded $CO_2$ (including biogenic $CO_2$ important in the short term) in the GHG 311balance because a high emission of this gas indicates a high stabilization rate of the products as plant 312litter (humus), which is generally excluded from GHG balances. Thus when the $CO_2$ emitted by 313vermicomposting is omitted, the process emits less GHG than conventional composting in these 314studies. However, one study showed that vermicomposting can emit more $N_2O$ than composting 315(Hobson et al. 2005), suggesting that the process is variable, probably depending on the type of 316material being decomposed and how well it works.

317

318One other advantage of vermicomposting to valorize OFMSW in an urban context is that it is an 319odorless process (Lleo et al. 2013). Thus it can be carried out indoors or in cellars and on several 320scales and be adapted for domestic use (Sherman and Appelhof 2011; Pirsaheb et al. 2013). It can also 321be adapted for collective use or on platforms ranging from "low-tech" in windrows (Edwards 2011a; 322Hanc et al. 2017) to "high-tech" in industrial scale vermicomposters (Jain et al. 2003; Gajalakshmi et 323al. 2005; Edwards 2011b). Unlike collective vermicomposters, which aim to recycle waste close to 324where people produce it (e.g. at the bottom of buildings), platforms are defined as sites to which 325organic waste is transported and stockpiled to recycle a larger quantity of material (generally carried
326out by companies). Thus, it is possible to recycle OFMSW using vermicomposting in any available 327space, for example at individual homes, office or apartment buildings or after collection by 328professionals. Both vermicomposting and composting can be used to recycle food waste but also other 329sources of organic waste traditionally found in city. Generally, in urban composting shredded green 330waste is co-composted (Adhikari et al., 2009; Farrell and Jones, 2010; Reyes-Torres et al., 2018) to 331improve control over the process (humidity, temperature, and so on). The added value of 332vermicomposting compared to other techniques is that it is possible to replace the shredded green 333waste (bulking agent) with paper and cardboard which are abundant resources in the cities, thus 334avoiding supply problems (pressure on green waste resource in cities with other uses such as 335mulching). In addition, there is no need to turn the material over as in composting because earthworms 336naturally mix the matter, which avoids handling. However, unlike composting, vermicomposting does 337not allow for the direct recycling of waste such as meat, fish and processed products (waste from high- 338fat cooked foods or uneaten ready-made meals, for example). For this reason, studies have sought to 339optimize the vermicomposting process by adding a pre-composting stage (Frederickson et al. 1997; 340Kalamdhad et al. 2009; Varma and Kalamdhad 2016). In our review, pre-composting was often used 341(Table 1: 27%), although this pre-treatment requires a significant additional cost. In the recovery 342platform, thermophilic pre-composting allows a "safer" hygienization of this type of waste and also 343accelerates the process of stabilizing OM (Nair et al. 2006; Frederickson et al. 2007; Hanc and Pliva 3442013).

345

346Another potential limitation to the widespread use of vermicomposting is that it is more complex than 347composting and requires more skills to understand and manage the conditions necessary for a 348successful earthworm life cycle (Lohri et al. 2017). Indeed, one of the main challenges of the process 349is to maintain sufficient moisture for the development of the earthworms (Munroe 2007). For example, 350in platforms, it is necessary to use watering during periods of drought, which will be increasingly 351frequent and constraining in many parts of the world, especially in the context of global warming. In 352the case of OFMSW recovery, and more particularly food waste, it is possible to manage humidity 353with the continuous supply of this type of waste because it is mainly composed of water. Depending 354on the region, seasonality can also influence the process, which will slow down at temperatures below 35510°C or higher than 35°C (depending on the species of earthworm used) (Edwards et al. 2010). One of 356the most complicated factors to manage in the case of OFMSW recovery is the heterogeneity of the 357materials entering the process, which could potentially influence the quality of the final product. 358Finally, the low temperature of the process raises questions about the hygienization (especially at 359European standards which require heat at 70 degrees for 3 days to eliminate pathogens) and reduction 360of weeds in vermicompost.

361

3623.2. *Quality of vermicompost from OFMSW*
363

364According to our review, vermicomposting increases the total contents of nitrogen (N), calcium (Ca), 365phosphorus (P), potassium (K) and magnesium (Mg) and decreases organic carbon (OC) content and 366thus the C/N ratio in relation to incoming products (Lim et al., 2015). The bibliography also shows 367that the action of earthworms optimizes the retention of nutrients such as N (Caceres et al., 2018) by 36810% to 20%, (according to the C:N value of the organic waste before recycling), compared to compost 369(Nigussie et al., 2016). In addition, nutrients in vermicompost are highly available to plants compared 370to compost (Adhikary, 2012; Samal et al., 2019), especially P and K (Hanc and Pliva, 2013). In fact, 371earthworms help to release nutrients such as P partly due to the presence of enzyme activities in their 372stomachs such as phosphatases (Ghosh et al., 1999).

373

### 374.3.2.1 Variability of vermicompost between studies

375

376Based on the typology presented in Table 2, we estimated the quality of the different vermicompost 377products as an organic amendment according to pH, C/N, OC, Ntot, P, K, Ca, Mg, Na, Cu, Fe, Mn, 378Zn, Cd, Cr, Ni and Pb criteria (Annex Table 2). The results were very heterogeneous from one report 379to another, especially regarding the metallic trace elements, which really depend on the quality of the 380incoming waste more than on the process itself. As the standards concerning the characterization of 381organic amendments vary from one country to another, we chose the French standard (NF U44-051 382adapted from the European law of "Organic soil improvers — Designations, specifications and 383marking" as the reference. This standard sets the threshold limits for metallic trace elements of As at 38418, Cd at 3, Cr at 120, Cu at 300, Hg at 2, Ni at 5.55, Pb at 180 and Se at 12 mg kg⁻¹. The levels of Cu 385and Cr were always below the norm. Cadmium, Ni and Pb means exceeded the standard threshold 386(annex table 2) because of only one study in which increases in the averages with three analyses above 38750 for Cd, above 900 for Pb and above 200 mg kg⁻¹ for Ni were observed (Varma and Kalamdhad 3882016). The mixtures concerned were generally OFMSW in which the OM had been roughly sorted, 389which may be the cause of the high level of trace elements in this category. Indeed, due to bad waste 390sorting, the OFMSW can contain other types of contaminant-rich waste (non-biological products e.g., 391plastics, glass). Overall, the products from the OFMSW appear to be in compliance with the standards 392concerning trace elements, although further studies on this subject are needed to increase the data and 393validate this trend.

394

395Concerning the agronomic parameters of organic amendments, the standard NF U44-051 sets 396minimum thresholds of C/N at 8 and dry matter at 30%. For agronomic value (in % of gross), OM 397should be at a minimum of 20%, i.e. 10% OC (OM / 2) and P, K and N must not exceed 3%. None of 398the included studies specified the dry matter content of the final product but the C/N mean values were 399within the correct range (Annex Table 2). The C/N ratio, which is a good indicator of nutrient intake
400(Diacono and Montemurro 2010), was highly variable depending on the type of waste used to make 401the vermicompost. Indeed, for C-rich waste such as paper and green waste the C/N is higher than for 402food waste (means of 17.21, 14.38 and 12.50, respectively). In a mixture of urban and agricultural 403wastes the C/N is higher, probably because of the large amount of C in this type of waste. We also 404noticed that the C/N of the various mixes was quite high with an average of 18.33 for the urban waste 405and 16.82 for the mixed urban and agricultural waste. This may be due to the heterogeneity of the 406substrate, which could complicate the process. Furthermore, the use of a bulking agent with food 407waste (paper) reduces the C/N to a mean of 10.43, a lower value than when only food was used. It 408would therefore be interesting to develop studies on the recovery of OFMSWs by mixing food waste 409and paper or waste from green spaces, which is more accessible in cities than agricultural waste such 410as manure.

411

412Regarding other agronomic values (OC, N, P and K in Figure 2) it is not possible to know if the 413vermicomposts are within the NF U44-051 standard since the reported analyses were carried out on 414dry products and the moisture content was generally not specified. However, Figure 2 shows that 415vermicompost from food waste without mixing with agricultural resources is rich in N (1.59%) and P 416(1.18%), and especially in K (2.34%), but lowest in C (18.83%). In contrast, vermicomposts from 417green waste are rich in C (25%) and lower in P (0.73%) and K (1.25%). Overall the addition of 418agricultural waste increased the nutrient values in vermicompost probably due to the capacity of 419epigeic earthworms to readily degrade animal manure which in turn provided them with an optimum 420living environment (Munroe 2007; Edwards et al. 2010). In urban waste management it would be 421more interesting to combine food with green waste (or paper or both) as bulking agents because these 422resources are more available in an urban context, thus avoiding transportation of materials. In our 423review, only four studies analyzed vermicompost from food waste and green waste, and only 11 from 424food waste and paper, so we could not compute average values. The food/paper mixture increased OC 425to 28.53% and N to 2.58%, showing that a mixture of more N-rich (food) and more C-rich (paper) 426feedstock can optimize the recovery of these wastes if they are combined rather than treated 427individually. Again this may be due to the fact that appropriate mixtures create better living conditions 428for earthworms, which then optimizes vermicomposting processes.
<figure><img src="image_3.png" /><figcaption>(b)</figcaption></figure>

<figure><img src="image_4.png" /><figcaption>(c)</figcaption></figure>

<figure><img src="image_5.png" /></figure>
<figure><img src="image_6.png" /></figure>

429**Figure 2:** Means and standard deviations of the organic carbon content (a), nitrogen content (b), potassium (c) and phosphorus content (d). The number in bold in the barplots is the number of repetitions for calculating means. The letter (U) corresponds to the average for urban waste only and the letters (U+A) correspond to the average for urban and agricultural waste.

433

### 4343.2.2 Comparison of the quality of vermicompost and compost from the same OFMSW

435

436To better evaluate the quality of vermicompost from OFMSWs and disregard studies with variable inputs, we compared it to "classic" compost produced from exactly the same material. This issue was only addressed in 35 of the 184 articles. Table 3 shows the difference in agronomic chemical parameters between vermicompost and compost from the same wastes with the help of paired tests.
440There were several significant differences between the quality of compost and vermicompost from the urban waste especially for pH, which was slightly more neutral for vermicompost (7.59) than for compost (7.86), and for the C/N, which was lower for vermicompost (15.05) than compost (16.93).
443The vermicompost also had a higher percentage of total N and P than the compost (1.54% versus 31% for N and 56% versus 3% for P). Organic OC and K levels were not significantly different.
445When compost and vermicompost of urban waste added to agricultural waste were compared, the C/N and OC of vermicompost were also significantly lower than compost (16.1 vs. 24.45 and 25.26% vs. 22%). While total N was not significantly different in spite of a strong difference in averages (2.33% for vermicompost versus 1.49% for compost). In both types of waste (urban alone or with agricultural waste) the C/N was significantly lower for the vermicompost and the OC content was also lower
450(significantly for the mixture with agricultural waste), and the total N rates were higher (significantly 451for the urban waste alone). According to the review, vermicomposting emits more CO₂ than 452composting because of its higher biological activity but lower CH₄, which reduces carbon losses in 453total C footprints and allows better N retention (less N₂O emission) (Nigussie et al. 2016, 2017). The 454significant difference in OC from urban and agricultural wastes is certainly due to the fact that the 455earthworms can easily degrade animal manure. According to these results, vermicompost should have 456similar fertilizing properties to compost, although its agronomic parameters may even be slightly more 457suitable for crop production (lower C/N, higher nutrient contents). Moreover, all these studies were 458mostly focused on the valorization of a specific type of waste such as 100% green waste or 100% food 459waste or a mix of OFMSW with no pre-selection of waste and only one analysis took into account a 460mixture of food and paper wastes which, as we have seen in the previous section, would be more 461appropriate for vermicomposting. According to Yadav and Garg (2011), it is essential to rigorously 462select raw materials and mixtures to optimize the vermicomposting process and obtain a better quality 463product. Also, classical chemical analyses do not take into account many other factors such as plant 464growth regulators (PGRs), plant growth hormones (PGHs), nutrient availability, OM quality or 465microbiological activity. All are essential factors for plants growth (Soobhany et al. 2017; Barthod et 466al. 2018; Dominguez et al. 2019).

467

<table><thead><tr><th>Type of organic waste</th><th>Chemical factor</th><th>Compost</th><th>Vermicompost</th><th>Test with repetition</th></tr></thead><tbody><tr><td rowspan="6">Urban wastes only</td><td>pH</td><td>7.86 ± 0.75<sup>a</sup></td><td>7.59 ± 0.71<sup>b</sup></td><td>Student (n = 21)</td></tr><tr><td>C/N</td><td>16.93 ± 5.71<sup>a</sup></td><td>15.05 ± 5.46<sup>b</sup></td><td>Wilcoxon (n = 18)</td></tr><tr><td>OC (%)</td><td>24.54 ± 9.04<sup>a</sup></td><td>23.04 ± 7.44<sup>a</sup></td><td>Student (n = 18)</td></tr><tr><td>Ntot (%)</td><td>1.31 ± 0.74<sup>b</sup></td><td>1.54 ± 0.65<sup>a</sup></td><td>Wilcoxon (n = 25)</td></tr><tr><td>P (%)</td><td>0.53 ± 0.51<sup>b</sup></td><td>0.56 ± 0.37<sup>a</sup></td><td>Wilcoxon (n = 22)</td></tr><tr><td>K (%)</td><td>1.23 ± 0.94<sup>a</sup></td><td>1.26 ± 0.8<sup>a</sup></td><td>Wilcoxon (n = 16)</td></tr><tr><td rowspan="3">Urban and agricultural wastes</td><td>C/N</td><td>24.45 ± 7.75<sup>a</sup></td><td>16.11 ± 5.05<sup>b</sup></td><td>Student (n = 7)</td></tr><tr><td>OC (%)</td><td>33.22 ± 2.32<sup>a</sup></td><td>25.26 ± 7.62<sup>b</sup></td><td>Student (n = 7)</td></tr><tr><td>Ntot (%)</td><td>1.49 ± 0.43<sup>a</sup></td><td>2.33 ± 1.79<sup>a</sup></td><td>Student (n = 7)</td></tr></tbody></table>

468

469**Table 3:** Matched comparison of vermicomposts and composts from the same waste origin.

470Superscript letters in bold indicate statistical differences with a p-value less than 0.05.

471

4723.3 *Benefits and limitations of using vermicompost from OFMSW in agriculture soils*

473

4743.3.1 *Effects on crop yield*

475

476In our study, we found 18 papers that assessed the impact of vermicompost from OFMSW on crop 477yields under field conditions. All these papers found that vermicompost had a positive effect on 478biomass and crop yield. Arancon et al., (2005, 2003a) showed improved yields for pepper, tomato and
479strawberry when vermicompost was supplemented with inorganic nitrogen fertilizers compared to 480inorganic fertilizers alone (same N dose in the different treatments). The same effect was shown for 481rice compared to the inputs of non-vermicomposted waste and a control with no inputs (Mishra et al. 4822005), and compared to the contribution of NPK alone or to NPK with farmyard manure (Sahariah et al. 483al. 2020). Yields also increased for ginger compared to a control (no input) and vermicompost from 484cow manure (the best yield in this study was the treatment with vermicompost from paper sludge) (Eo 485and Park 2019). Olive grove yield increased 35.5% and the nutrients in olive fruit were significantly 486different compared to the control and better than compost from MSW and sheep manure (Tejada and 487Benitez 2020). Yields also increased for bean compared to pressmud, flower waste and farmyard 488manure (Sajitha et al. 2007) and for pea compared to cattle manure (Abdrabbo et al. 2014). Pattnaik 489and Reddy, (2010, 2011) showed that vermicompost has significant results on the growth of fenugreek 490(*Trigonella foenum-graecum* L.) and tomato (*Lycopersicum esculentum* Mill.) compared to compost 491from the same OFMSW. In addition, Arancon et al. (2005, 2003a) showed that vermicompost 492(supplemented with inorganic fertilizers to equalize the initial N levels available to plants) has a 493greater impact than inorganic fertilizers (NPK) alone on marketable yield and dry shoot weight of 494pepper. The addition of NPK nutrients to vermicompost to achieve nitrogen equivalence shows that 495vermicompost has other factors that promote plant growth. According to Arancon et al. (2005, 2003a), 496it is not only the available elements such as N and P in vermicompost that enable plant growth, but 497also/rather the high biological activity and increased production of PGRs, such as humic acids, and 498PGHs.

499

500In contrast, Roberts et al., (2007) showed that vermicompost from green waste and sewage sludge, 501while increasing tomato plant germination and fruit quality, did not increase total fruit yield, 502marketable fruit yield, fruit number, fruit weight, or vitamin C concentration compared to commercial 503peat-based compost. Eo and Park (2019) found that at high doses (40 t ha⁻¹), vermicompost from 504OFMSW increased root disease in ginger (*Panax ginseng*). However, with moderate use (10 t ha⁻¹ 505here) it had a positive impact on root growth. This shows that excessive inputs can lead to nutrient 506surpluses that can harm the crop and/or the environment. For example, in their experiment a 40 t ha⁻¹ 507input of vermicompost is equivalent to 520 kg of N per hectare (vermicompost = 1.3% N), which is 508harmful to the crop and can also lead to pollution due to nitrogen leaching. It is therefore necessary to 509properly characterize the products before use in the field.

510

511Mishra et al. (2005) showed that the use of vermicompost increases the chlorophyll concentration in 512rice leaves. This was further corroborated by Tejada and Benitez (2020) who found an increase in 513micro and macro nutrients in olive leaves. Arancon et al. (2005, 2003a) showed that the high fulvic 514acid and protein content in vermicompost are easily degradable by soil microorganisms and 515assimilated by plants. Yardim et al. (2006) have demonstrated that a decrease in crop pests was related
516to a high dose of nitrogen in the foliage and a phenolytic compound that is stimulated by the addition
517of vermicompost.

518

519Vermicompost from OFMSW is a highly variable product (see section 3.3) and it is therefore difficult
520to generalize about its impact in the field from the few published studies. Moreover, in most of these
521studies there was no control in the strict sense of the word because vermicompost was compared to
522inorganic fertilizers (NPK) or cattle manure. It is possible to compare different products with each
523other, but without a proper control it is not possible to measure the effect compared to a treatment
524without material input. However, the findings from the application of vermicompost from OFMSW
525are consistent with the positive reports for the application of vermicompost from manure in the field
526(Tringovska and Dintcheva 2012; Guo et al. 2015; Velecela et al. 2019; Aslam et al. 2019; Tejada and
527Benitez 2020).

528

5293.3.2 *Effects in soil (bio-physico-chemical)*

530

531It is widely recognized in the literature that OM inputs of any kind, such as biochar (Atkinson et al. 5322010; Yadav et al. 2019), compost or manure (Obriot et al. 2016; Kelley et al. 2020), have positive 533effects on soil physico-chemical qualities (Diacono and Montemurro 2010; Ghosh et al. 2010; Peltre et 534al. 2017). We only found four papers that addressed the impact of vermicompost from OFMSW on the 535soil and its bio-physical-chemical parameters in the field. All these studies showed that vermicompost 536input increased soil pH (Eo and Park 2019) and carbon storage compared to the contribution of NPK 537alone or to NPK with farmyard manure (Sahariah et al. 2020). It also increased levels of the soil 538nutrients N, P, K when supplemented with inorganic fertilizers to balance fertilizer recommendations 539compared to inorganic fertilizers alone (Arancon et al., 2006b). Only Sahariah et al. (2020) studied the 540evolution of soil physical parameters and showed that vermicompost increased the soil water retention 541capacity and reduced bulk density compared to the contribution of NPK alone or to NPK with 542farmyard manure. At the same time, these authors studied soil microbiology following the application 543of vermicompost. They all observed that vermicompost increased soil microbial biomass and enzyme 544activities (dehydrogenase, urease, β-glucosidase, phosphatase and arylsulfatase) compared to MSW, 545sheep manure and control, and the enzyme-humus complex compared to the control (Tejada and 546Benitez 2020), as well as soil respiration measured by dehydrogenase activity (Arancon et al., 2006b). 547Arancon et al. (2006b) showed that increases in dehydrogenase activity and microbial biomass were 548positively correlated with increases in NH₄-N, NO₃-N and orthophosphates. The same authors 549demonstrated that these activities promote nutrient cycling rates, the production of plant growth 550regulating materials and the accumulation of plant resistance or tolerance to pathogen attack. 551According to these authors, plant growth is stimulated not only by nutrients in the vermicompost, but 552also due to the microbiological activity and diversity of the product. This leads to improved rates of
553nutrient cycling in the soil and protection of plants against diseases through competition and 554antagonism against other pathogenic organisms. Arancon et al. (2003b) also showed that 555vermicompost allows parasite regulation at the level of soil microfauna by decreasing parasitic 556nematodes and increasing the populations of fungivorous and bacterivorous nematodes compared to 557inorganic fertilizer or a control without fertilizer. For meso and macrofauna, Gunadi et al. (2002) 558showed an increase in saprophagous arthropods (Collembola as *Isotomidae*, *Onychiuridae*, 559*Sminthuridae*, Acari as *Cryptostigmata* and *Symphyla*) following the addition of vermicompost 560(compared to inorganic fertilizer or compost) and also hypothesized that this could be due to the high 561microbiological activity of the product.

562

## 5634 Outlook and future studies

564

### 5654.1 Studies on the process of vermicomposting using OFMSW

566

567We found that there is a lack of research on the applications of vermicompost from OFMSW in 568agriculture. Indeed the majority of research focused on the process of vermicomposting this type of 569waste. This is justified by the great diversity of materials included in the OFMSW, which are present 570in variable proportions depending on the country and its level of development (Troschinetz and 571Mihelcic 2009). Thus, the variability of the incoming OM can lead to an additional complication in 572running waste recovery programs. However, Hanc et al. (2011) showed that in the same city, the 573composition of bio-waste (type and chemistry) over four seasons varied little in urban areas (mainly 574fruit and vegetables) but was more influenced by home garden management. Therefore, with a prior 575analysis of OFMSW, it may be possible to predict the quality of vermicomposts obtained either by 576modeling (Hosseinzadeh et al. 2020) or case-by-case studies with different bulking agents depending 577on available resources (e.g. cow manure in India).

578

579Despite a lot of research on the processes, there are still avenues for improvement to optimize the 580valorization of OFMSW by vermicomposting and improve the understanding of the fundamental 581processes related to this technique. For example, some studies looked at mixtures of earthworm 582species with different functions (Suthar and Singh 2008) or searched for native and readily available 583species (Suthar 2009) rather than *E. fetida*. On larger scales (semi-industrial platforms for example), 584the parameters necessary for the process to run smoothly (e.g. temperature, humidity, pH) are much 585harder to control, which can lead to changes in the process and increase the variability of the derived 586product.

587

### 5884.2 Use of vermicompost from OFMSW in the field

589
590Although we have gathered some information on the impact of vermicompost in the field, some points 591have not yet been studied. For example, in their meta-analysis, Blouin et al. (2019) showed that the 592species most receptive to vermicompost are Cucurbitaceae, Asteraceae, Fabaceae, and Poaceae. In 593addition, in our review, we found that the majority of studies using vermicompost from OFMSWs 594were focused on ornamental plants or vegetable crops and we could not find studies about cereals such 595as wheat, barley and maize.

596

597The low temperature of the process could have benefits that have been little studied such as a positive 598effect on soil biodiversity. Although most studies agree that vermicomposting increases the taxonomic 599and functional diversity of bacterial communities (Dominguez et al. 2019) as well as the functioning 600of a microdecomposer food web (Aira et al. 2008), only a few studies evaluated the impact of the 601process on meso and macrofauna abundance and diversity. However, Monroy et al., (2011) showed an 602increase in the total number of arthropods in the presence of *E. fetida* (especially springtails and 603mesostigmatid mites), suggesting that the development of large populations of soil arthropods is a 604characteristic of the initial stages of the earthworm mediated decomposition process. Of the seven 605groups of arthropods monitored (springtails; mites: astigmatids, prostigmatids, mesostigmatids and 606oribatids; psocids and spiders), only the psocids were negatively affected by the presence of *E. fetida*. 607Sampedro and Domínguez (2008) also used ¹³C and ¹⁵N to show that earthworms interact intensively 608with other detritivores such as bacteria, fungi and other soil fauna.. This work, which aimed to classify 609relative trophic positions, using pig and cow manure separately in two different systems, showed that 610the microdecomposer community was different depending on the stage of the earthworm life cycle 611(adults, hatchlings and cocoons) and resource quality. Thus, in view of its biological quality, studies 612on the impact of vermicompost, after field application, on soil macrofauna such as earthworm 613populations and mesofauna such as springtails or mites are a promising route, especially because these 614are excellent bioindicators of soil quality (Gulvik 2007; Peres et al. 2011).

615

### 6164.3 Comparison with other techniques and integration into OFMSW management systems

617

618Comparative studies between the different techniques for the valorization of OFMSW are missing. For 619example, Lohri et al., (2017) revealed a disparity in publications on the technology of organic waste 620recovery and a real lack of field studies and suggested that more transdisciplinary research is needed 621using real case studies. The same authors concluded that as well as studying the fundamental 622processes, more focus should be placed on systems in application. In this way, various valorization 623techniques could be compared to validate the fundamental theory on the ground (rather than in the 624laboratory) and develop the techniques for recycling biowaste while upscaling. Moreover, in order to 625choose appropriate recycling techniques, Zhang et al., (2010) showed that it is necessary to separate 626the waste streams first to optimize their recovery process. For example, in developing countries, little
627investment is made in waste separation, which can lead to contamination with pathogens and/or 628pollutants limiting or excluding the choice in OFMSW recycling techniques. On the other hand, in rich 629countries, the flows are relatively well separated which allows a more diversified selection of 630recycling systems, including vermicomposting. However, this low-tech technique is developing 631particularly well in Asia (especially in India), while few European researchers are interested in this 632process. Indeed, a small number of reports compared the life cycle of other OFMSW recovery 633techniques such as composting or methanisation with vermicomposting (Komakech et al. 2015; 634Nigussie et al. 2016) but few studies evaluated the products of these techniques at the agronomic level 635in the field. A comparison would make it possible to assess the advantages and disadvantages of each 636method and to guide regions towards an adapted management of their OFMSW according to their 637needs. Bortolotti et al. (2018) showed that decentralization of organic waste management via several 638possible scenarios could be a promising alternative to centralized industrial facilities. This type of 639management would be perfectly adapted to vermicomposting, which is particularly suitable in urban 640areas. Indeed, in a circular economy approach, some of the OFMSW could be recovered by collective 641vermicomposting in the city and some on peri-urban platforms where different techniques would allow 642the recovery of all the OM (for example pre-composting or methanisation of waste that is difficult to 643manage in vermicomposting). Thus, the vermicompost produced in cities could be used in urban 644agriculture and/or collected for use in peri-urban agriculture (reduced transport compared to the 645collection of raw OFMSW) and the products from the peri-urban platforms would be reserved for 646local agriculture.

647

648.4. *Socio-economic issues*

649

650We found little information on the economic and social impact of the practice of vermicomposting and 651the use of vermicompost in agriculture. According to Lim et al. (2016), economic evaluations of 652vermicomposting are scarce and there are differing opinions: some activities are profitable and others 653are not, depending on the type of process used, the market value of the organic fertilizer and the 654production volume. However, vermicomposting is a feasible organic waste management strategy 655because, like composting, it is a process with lower operating costs than other waste management 656options (Ruggieri et al. 2009). As with composting systems, the economic potential of a 657vermicomposting system depends on the initial capital costs (e.g., high-tech indoor or low-tech 658outdoor windrow system) as well as the revenues from the vermicompost produced. Prices vary 659widely around the world, with a selling price of $80 per ton of vermicompost in Uganda (Lalander et 660al. 2015) compared to $200 to $1000 per ton in the United States (Edwards et al. 2010) and $200 to 661$2500 in France depending on the type of packaging (wholesale for professionals or retail for 662individuals). The commercialization of the earthworms produced during the process can be an 663additional economic gain because they are rich in protein (65% of the dry matter) and can be used as
664meal for animal feed (Adhikary 2012; Lalander et al. 2015) or even for human consumption (Tedesco 665et al. 2019; Conti et al. 2019). Earthworms can typically sell for $5 to $35 per pound in the United 666States (Edwards et al. 2010). At the same time, new technologies such as worm sorters have been 667developed in recent years, which facilitate the extraction of worms from vermicompost for their 668commercialization (Lin et al. 2021). In the context of OFMSW valorization, one of the potential 669sources of income for vermicomposting activities would be directly from the collection and/or 670valorization of organic wastes from businesses and communities because in certain areas of the world 671and in particular in Europe (European Union 2018) mandates are in place for waste recover by the end 672of 2023. To our knowledge, no study has integrated the benefits of collection/costs of recovery of 673OFMSW with a vermicomposting system. At the same time, there is a lack of policies favorable to the 674implementation of sustainable waste management practices, minimal legislation concerning waste 675recovery, and insufficient international influence from developed countries, to support the 676development of sustainable waste management in developing countries that do not have the means to 677implement the same waste management policies (Marshall and Farahbakhsh 2013). This is an 678additional constraint for the development of processes such as vermicomposting and a curb on the 679development of this technique at larger scales.

680

## 6815 Conclusions

682

683This review examined the value of the vermicomposting process in its entire loop/cycle, from the 684recovery of OFMSW to the application of vermicompost in the field. According to the literature 685studied, vermicomposting is perfectly adapted to the valorization of OFMSW. Indeed, earthworms can 686degrade these materials and produce a vermicompost that is beneficial for agriculture. We have shown 687that the vermicompost is an amendment with interesting fertilizing properties like compost, although 688its agronomic parameters seem to be slightly more suitable for crop production. Indeed, vermicompost 689had a greater effect on soil, plant growth and yield than compost, probably due to other parameters 690such as microbiology, mineralization potential or PGRs and PGHs. With evolving environmental 691issues and increasingly strict regulatory constraints, vermicomposting could be a suitable response to 692waste management in the context of the circular economy. However, our study also revealed a lack of 693research on vermicomposting, especially regarding field studies. These studies would provide a better 694understanding of the vermicomposting process and its applications, which in turn could accelerate 695progress in its uptake as an interesting approach for reconciling waste recovery and sustainable 696agricultural development. Vermicomposting of OFMSW is a promising solution for linking waste 697management and sustainable agriculture, but for this to happen, in-depth research on the quality of the 698vermicompost produced and its impact on agricultural soils in the long term must be developed. These 699studies could lead to a standardization, distinct from that for classical compost, so that the use of this 700technique and product becomes widespread.
701Author's declarations

702

703Funding

704The research leading to these results has received funding from "Association Eisenia"
705(https://eisenia.org/), ANRT (https://www.anrt.asso.fr/fr) and ADEME (https://www.ademe.fr/) for the
706financing of the "VALOR" project via the "GRAINE" calls for research projects.

707

708Conflicts of interest/Competing interests

709The authors have no conflict of interests or competing interests to declare.

710

711Ethics approval

712Not applicable.

713

714Consent to participate

715Not applicable.

716

717Consent to publication

718Not applicable.

719

720Availability of data and material

721All articles analyzed were previously published and are available online (on Web of Science). See also
722Supplementary Table 1.

723

724Code availability

725The code used in this article is available from the corresponding author upon reasonable request.

726

727Authors' contributions

728Conceptualization, VD, JP, YC; Methodology, VD, JP, YC; Investigation, VD; Formal analysis, VD;
729supervision, project administration, JP, YC; writing and editing VD, JP, YC; Funding acquisition, VD,
730JP. All authors read and approved the final manuscript.

731

732

733

734

735

736
7376 Bibliography

738

739Abdrabbo M, Refaie K, Ramadan A (2014) Influence of vermicompost and plant density on
740sustainable production of peas. Arab Univ J Agric Sci 22:55–65.

741 https://doi.org/10.21608/ajs.2014.14702

742

743Adhikary S (2012) Vermicompost, the story of organic gold: A review. Agric Sci 3:905–917.

744 https://doi.org/10.4236/as.2012.37110

745Agarwal S, Arora L (2011) Vermiculture biotechnology for waste management in different seasons: a
746case study. J Dairy Foods Home Sci 30:209–214.

747

748Aira M, Monroy F, Dominguez J (2007) *Eisenia fetida* (Oligochaeta: Lumbricidae) modifies the
749structure and physiological capabilities of microbial communities improving carbon mineralization
750during vermicomposting of pig manure. Microb Ecol 54:662–671.

751 https://doi.org/10.1007/s00248-007-9223-4

752

753Aira M, Sampedro L, Monroy F, Dominguez J (2008) Detritivorous earthworms directly modify the
754structure, thus altering the functioning of a microdecomposer food web. Soil Biol Biochem 40:2511–
7552516.

756 https://doi.org/10.1016/j.soilbio.2008.06.010

757

758Ali U, Sajid N, Khalid A, et al (2015) A review on vermicomposting of organic wastes. Environ Prog
759Sustain Energy 34:1050–1062.

760 https://doi.org/10.1002/ep.12100

761

762Alshehrei F, Ameen F (2021) Vermicomposting: A management tool to mitigate solid waste. Saudi J
763Biol Sci 28:3284–3293.

764 https://doi.org/10.1016/j.sjbs.2021.02.072

765

766Arancon NQ, Edwards CA, Bierman P (2006) Influences of vermicomposts on field strawberries: Part
767. Effects on soil microbiological and chemical properties. Bioresour Technol 97:831–840.

768 https://doi.org/10.1016/j.biortech.2005.04.016

769

770Arancon NQ, Edwards CA, Bierman P, et al (2003a) Effects of vermicomposts on growth and
771marketable fruits of field-grown tomatoes, peppers and strawberries: The 7th international symposium
772on earthworm ecology · Cardiff · Wales · 2002. Pedobiologia 47:731–735.

773 https://doi.org/10.1078/0031-4056-00251
774

775Arancon NQ, Edwards CA, Bierman P, et al (2005) Effects of vermicomposts produced from cattle manure, food waste and paper waste on the growth and yield of peppers in the field. *Pedobiologia* 77:49-297-306.

778https://doi.org/10.1016/j.pedobi.2005.02.001

779

780Arancon NQ, Galvis P, Edwards C, Yardim E (2003b) The trophic diversity of nematode communities in soils treated with vermicompost. *Pedobiologia* 47:736-740.

782https://doi.org/10.1078/0031-4056-00752

783

784Aslam Z, Bashir S, Hassan W, et al (2019) Unveiling the Efficiency of Vermicompost Derived from Different Biowastes on Wheat (*Triticum aestivum* L.) Plant Growth and Soil Health. *Agronomy* 9:791.

786https://doi.org/10.3390/agronomy9120791

787

788Atiyeh RM, Subler S, Edwards CA, et al (2000) Effects of vermicomposts and composts on plant growth in horticultural container media and soil. *Pedobiologia* 44:579-590.

790https://doi.org/10.1078/S0031-4056(04)70073-6

791

792Atkinson CJ, Fitzgerald JD, Hipps NA (2010) Potential mechanisms for achieving agricultural benefits from biochar application to temperate soils: a review. *Plant Soil* 337:1-18.

794https://doi.org/10.1007/s11104-010-0464-5

795

796Barles S (2014) History of waste management and the social and cultural representations of waste. In: Agnoletti M, Neri Serneri S (eds) The Basic Environmental History. Springer International Publishing, Cham, pp 199-226.

799https://doi.org/10.1007/978-3-319-09180-8_7

800

801Barthod J, Rumpel C, Calabi-Floody M, et al (2018) Adding worms during composting of organic waste with red mud and fly ash reduces CO₂ emissions and increases plant available nutrient contents.

803J Environ Manage 222:207-215.

804https://doi.org/10.1016/j.jenvman.2018.05.079

805

806Bernstad Saraiva Schott A, Wenzel H, La Cour Jansen J (2016) Identification of decisive factors for greenhouse gas emissions in comparative life cycle assessments of food waste management – an analytical review. *J Clean Prod* 119:13-24.

809https://doi.org/10.1016/j.jclepro.2016.01.079
810

811Bhada-Tata P, Hoornweg D (2012) What a waste? : a global review of solid waste management.

812Urban development series; knowledge papers no. 15. World Bank, Washington, DC. © World Bank.

813https://openknowledge.worldbank.org/handle/10986/17388 License: CC BY 3.0 IGO.

814

815Blouin M, Barrere J, Meyer N, et al (2019) Vermicompost significantly affects plant growth. A meta-analysis. Agron Sustain Dev 39:34.

817https://doi.org/10.1007/s13593-019-0579-x

818

819Blouin M, Hodson M, Delgado EA, et al (2013) A review of earthworm impact on soil function and ecosystem services. Eur J Soil Sci 64:161-182.

821https://doi.org/10.1111/ejss/12025

822

823Board N (2004) The complete technology book on vermiculture and vermicompost. Asia Pacific

824Business Press Inc.

825

826Bortolotti A, Kampelmann S, De Muynck S (2018) Decentralised organic resource treatments - classification and comparison through extended material flow analysis. J Clean Prod 183:515-526.

828https://doi.org/10.1016/j.jclepro.2018.02.104

829

830Bottinelli N, Hedde M, Jouquet P, Capowiez Y (2020) An explicit definition of earthworm ecological categories - Marcel Bouché's triangle revisited. Geoderma 372:114361.

832https://doi.org/10.1016/j.geoderma.2020.114361

833

834Bouche MB (1977) Stratégies lombriciennes. Ecol Bull (Stockholm) Statens Naturvetensk Forsk 83525:122-132.

836

837Cao W, Vaddella V, Biswas S, et al (2016) Assessing the changes in E. coli levels and nutrient dynamics during vermicomposting of food waste under lab and field scale conditions. Environ Sci 839Pollut Res 23:23195-23202.

840https://doi.org/10.1007/s11356-016-7528-x

841

842Cardoza YJ (2011) *Arabidopsis thaliana* resistance to insects, mediated by an earthworm-produced organic soil amendment. Pest Manag Sci 67:233-238.

844https://doi.org/10.1002/ps.2059

845
846Conti C, Bacenetti J, Tedesco D (2019) Earthworms for feed production from vegetable waste:

847Environmental impact assessment. Environ Eng Manag J 18:2117-2122.

848

849Diacono M, Montemurro F (2010) Long-term effects of organic amendments on soil fertility. A

850review. Agron Sustain Dev 30:401-422.

851https://doi.org/10.1051/agro/2009040

852

853Doan TT, Henry-des-Tureaux T, Rumpel C, et al (2015) Impact of compost, vermicompost and

854biochar on soil fertility, maize yield and soil erosion in Northern Vietnam: A three year mesocosm

855experiment. Sci Total Environ 514:147-154.

856https://doi.org/10.1016/j.scitotenv.2015.02.005

857

858Doan TT, Jusselme DM, Lata J-C, et al (2013) The earthworm species *Metaphire posthuma* modulates

859the effect of organic amendments (compost vs. vermicompost from buffalo manure) on soil microbial

860properties. A laboratory experiment. Eur J Soil Biol 59:15-21.

861https://doi.org/10.1016/j.ejsobi.2013.08.005

862

863Dohaish EJAB (2020) Vermicomposting of Organic Waste with Eisenia fetida Increases the Content

864of Exchangeable Nutrients in Soil. Pak J Biol Sci 23:501-509.

865https://doi.org/10.3923/pjbs.2020.501.509

866

867Dominguez J (2004) State-of-the-art and new perspectives on vermicomposting research. In:

868Edwards. C.A., Ed., Earthworm ecology, CRC Press LLC, Boca Raton, pp 401-424.

869http://dx.doi.org/10.1201/9781420039719.ch20

870

871Dominguez J, Aira M, Kolbe AR, et al (2019) Changes in the composition and function of bacterial

872communities during vermicomposting may explain beneficial properties of vermicompost. Sci Rep

8739:9657.

874https://doi.org/10.1038/s41598-019-46018-w

875

876Edwards CA (2011a) Low-technology vermicomposting systems. In: Vermiculture technology:

877Earthworms, organic wastes, and environmental management, CRC Press LLC, Boca Raton, pp 79-90.

878

879Edwards CA (2011b) Medium- and High-technology vermicomposting systems. In: Vermiculture

880technology: Earthworms, organic wastes, and environmental management, CRC Press LLC, Boca

881Raton, pp 91-102.
882

883 Edwards CA, Arancon NQ, Sherman RL (2010) Vermiculture technology: Earthworms, organic

884 wastes, and environmental management, CRC Press LLC, Boca Raton.

885

886 Eo J, Park K-C (2019) Effect of vermicompost application on root growth and ginsenoside content of
887 *Panax ginseng*. J Environ Manage 234:458-463.

888 https://doi.org/10.1016/j.jenvman.2018.12.101

889

890 Ersahin Y (2010) The use of vermicompost products to control plant diseases and pests. In: Karaca A
891 (ed) Biology of Earthworms. Springer, Berlin, Heidelberg, 191-213.

892 https://doi.org/10.1007/978-3-642-14636-7_12

893

894 European Union (2018) Directive (UE) 2018/851 du Parlement européen et du Conseil du 30 mai
895 2018 modifiant la directive 2008/98/CE relative aux déchets (Texte présentant de l'intérêt pour
896 l'EEE).

897

898 Frederickson J, Butt KR, Morris RM, Daniel C (1997) Combining vermiculture with traditional green
899 waste composting systems. Soil Biol Biochem 29:725-730.

900 https://doi.org/10.1016/S0038-0717(96)00025-9

901

902 Frederickson J, Howell G, Hobson AM (2007) Effect of pre-composting and vermicomposting on
903 compost characteristics. Eur J Soil Biol 43:S320-S326.

904 https://doi.org/10.1016/j.ejsobi.2007.08.032

905

906 Gajalakshmi S, Ganesh PS, Abbasi SA (2005) A highly cost-effective simplification in the design of
907 fast-paced vermireactors based on epigeic earthworms. Biochem Eng J 22:111-116.

908 https://doi.org/10.1016/j.bej.2004.09.003

909

910 Ghisellini P, Cialani C, Ulgiati S (2016) A review on circular economy: the expected transition to a
911 balanced interplay of environmental and economic systems. J Clean Prod 114:11-32.

912 https://doi.org/10.1016/j.jclepro.2015.09.007

913

914 Ghosh S, Lockwood P, Daniel H, et al (2010) Short-term effects of organic amendments on properties
915 of a Vertisol. Waste Manag Res 28:1087-1095.

916 https://doi.org/10.1177/0734242X09359105

917
918Gomez-Brandon M, Lores M, Dominguez J (2012) Species-specific effects of epigeic earthworms on
919microbial community structure during first stages of decomposition of organic matter. Plos One
920:e31895.

921 https://doi.org/10.1371/journal.pone.0031895

922

923Gulvik ME (2007) Mites (Acari) as indicators of soil biodiversity and land use monitoring: A review.
924Pol J Ecol 55:415-440.

925Gunadi B, Edwards CA, Arancon NQ (2002) Changes in trophic structure of soil arthropods after the
926application of vermicomposts. Eur J Soil Biol 38:161-165.

927 https://doi.org/10.1016/S1164-5563(02)01139-1

928

929Guo L, Wu G, Li C, et al (2015) Vermicomposting with maize increases agricultural benefits by
930304 %. Agron Sustain Dev 35:1149-1155.

931 https://doi.org/10.1007/s13593-015-0307-0

932

933Hanc A, Castkova T, Kuzel S, Cajthaml T (2017) Dynamics of a vertical-flow windrow
934vermicomposting system. Waste Manag Res 35:1121-1128.

935 https://doi.org/10.1177/0734242X17725161

936

937Hanc A, Novak P, Dvorak M, et al (2011) Composition and parameters of household bio-waste in four
938seasons. Waste Manag 31:1450-1460.

939 https://doi.org/10.1016/j.wasman.2011.02.016

940

941Hanc A, Pliva P (2013) Vermicomposting technology as a tool for nutrient recovery from kitchen bio-
942waste. J Mater Cycles Waste Manag 15:431-439.

943 https://doi.org/10.1007/s10163-013-0127-8

944

945Hobson A, Frederickson J, Dise NB (2005) CH₄ and N₂O from mechanically turned windrow and
946vermicomposting systems following in-vessel pre-treatment. Waste Manag 25:345-52.

947 https://doi.org/10.1016/j.wasman.2005.02.015

948

949Hogg D, Favoino E, Nielsen N, et al (2002) Economic analysis of options for managing biodegradable
950municipal waste. Final report to the European Commission. Bristol.

951 https://ec.europa.eu/environment/pdf/waste/compost/econanalysis_finalreport.pdf

952
953Hosseinzadeh A, Baziar M, Alidadi H, et al (2020) Application of artificial neural network and
954multiple linear regression in modeling nutrient recovery in vermicompost under different conditions.

955Bioresour Technol 303:122926.

956https://doi.org/10.1016/j.biortech.2020.122926

957

958Hrebeckova T, Wiesnerova L, Hanc A (2019) Changes of enzymatic activity during a large-scale

959vermicomposting process with continuous feeding. J Clean Prod 239:UNSP 118127.

960https://doi.org/10.1016/j.jclepro.2019.118127

961

962Jain K, Singh J, Gupta SK (2003) Development of a modified vermireactor for efficient

963vermicomposting: a laboratory study. Bioresour Technol 90:335-337.

964https://doi.org/10.1016/S0960-8524(03)00048-8

965

966Jouquet P, Doan T, M R, et al (2011) Do compost and vermicompost improve macronutrient retention

967and plant growth in degraded tropical soils? Compost Sci Util 19:15-24.

968https://doi.org/10.1080/1065657X.2011.10736972

969

970Kalamdhad AS, Singh YK, Ali M, et al (2009) Rotary drum composting of vegetable waste and tree

971leaves. Bioresour Technol 100:6442-6450.

972https://doi.org/10.1016/j.biortech.2009.07.030

973

974Kaviraj, Sharma S (2003) Municipal solid waste management through vermicomposting employing

975exotic and local species of earthworms. Bioresour Technol 90:169-173.

976https://doi.org/10.1016/S0960-8524(03)00123-8

977

978Kelley A, Wilkie AC, Maltais-Landry G (2020) Food-based composts provide more soil fertility

979bBenefits than cow manure-based composts in sandy soils. Agriculture 10:69.

980https://doi.org/10.3390/agriculture10030069

981

982Kibblewhite MG, Ritz K, Swift M j (2008) Soil health in agricultural systems. Philos Trans R Soc B

983Biol Sci 363:685-701.

984https://doi.org/10.1098/rstb.2007.2178

985

986Komakech AJ, Sundberg C, Jönsson H, Vinnerås B (2015) Life cycle assessment of biodegradable

987waste treatment systems for sub-Saharan African cities. Resour Conserv Recycl 99:100-110.

988https://doi.org/10.1016/j.resconrec.2015.03.006
989

990Lalander CH, Komakech AJ, Vinnerås B (2015) Vermicomposting as manure management strategy
991for urban small-holder animal farms - Kampala case study. Waste Manag 39:96–103.

992https://doi.org/10.1016/j.wasman.2015.02.009

993

994Lim SL, Lee LH, Wu TY (2016) Sustainability of using composting and vermicomposting
995technologies for organic solid waste biotransformation: recent overview, greenhouse gases emissions
996and economic analysis. J Clean Prod 111:262–278.

997https://doi.org/10.1016/j.jclepro.2015.08.083

998

999Lim SL, Wu T, Lim P, Shak K (2014) The use of vermicompost in organic farming: Overview, effects
1000on soil and economics. J Sci Food Agric 95:.

1001https://doi.org/10.1002/jsfa.6849

1002

1003Lin J, Zhao S, Yuan Q, et al (2020) Rapidly separating earthworm from vermicompost using two-step
1004technology. Waste Biomass Valorization 12:757–771.

1005https://doi.org/10.1007/s12649-020-01028-y

1006

1007Lleo T, Albacete E, Barrena R, et al (2013) Home and vermicomposting as sustainable options for
1008biowaste management. J Clean Prod 47:70–76.

1009https://doi.org/10.1016/j.jclepro.2012.08.011

1010

1011Lohri CR, Diener S, Zabaleta I, et al (2017) Treatment technologies for urban solid biowaste to create
1012value products: a review with focus on low- and middle-income settings. Rev Environ Sci Bio-
1013Technol 16:81–130.

1014https://doi.org/10.1007/s11157-017-9422-5

1015

1016Manivannan S, Balamurugan M, Parthasarathi K, et al (2009) Effect of vermicompost on soil fertility
1017and crop productivity - Beans (*Phaseolus vulgaris*). J Environ Biol Acad Environ Biol India 30:275–
101881.

1019

1020Marshall RE, Farahbakhsh K (2013) Systems approaches to integrated solid waste management in
1021developing countries. Waste Manag 33:988–1003.

1022https://doi.org/10.1016/j.wasman.2012.12.023

1023
1024Martin KL, Emanuel RE, Vose JM (2018) Terra incognita: The unknown risks to environmental
1025quality posed by the spatial distribution and abundance of concentrated animal feeding operations. Sci
1026Total Environ 642:887-893.

1027https://doi.org/10.1016/j.scitotenv.2018.06.072

1028

1029Mathivanan M, Saravanan GAV, Baji A, Kumar JM (2017) Biodegradation of paper waste using
1030*Eisenia foetida* by vermi-composting Technology. In: International Conference on Civil Engineering
1031and Infrastructural Issues in Emerging Economies (icciee 2017). Iop Publishing Ltd, Bristol, p UNSP
1032012051.

1033

1034Mishra M, Sahu R, Sahu S, Padhy R (2005) Effect of vermicomposted municipal solid wastes on
1035growth, yield and heavy metal contents of rice (*Oryza sativa*). Fresenius Environ Bull 14:584-590.

1036

1037Monroy F, Aira M, Domínguez J (2008) Changes in density of nematodes, protozoa and total
1038coliforms after transit through the gut of four epigeic earthworms (Oligochaeta). Appl Soil Ecol
103939:127-132.

1040https://doi.org/10.1016/j.apsoil.2007.11.011

1041

1042Monroy F, Aira M, Domínguez J (2011) Epigeic earthworms increase soil arthropod populations
1043during first steps of decomposition of organic matter. Pedobiologia 54:93-99.

1044https://doi.org/10.1016/j.pedobi.2010.10.003

1045

1046Munroe G (2007) Manual of on-farm vermicomposting and vermiculture. Org Agric Cent Can, Nova
1047Scotia.

1048

1049Nair J, Sekiozoic V, Anda M (2006) Effect of pre-composting on vermicomposting of kitchen waste.
1050Bioresour Technol 97:2091-2095.

1051https://doi.org/10.1016/j.biortech.2005.09.020

1052

1053Nigussie A, Kuyper TW, Bruun S, de Neergaard A (2016) Vermicomposting as a technology for
1054reducing nitrogen losses and greenhouse gas emissions from small-scale composting. J Clean Prod
1055139:429-439.

1056https://doi.org/10.1016/j.jclepro.2016.08.058

1057
1058Obriot F, Stauffer M, Goubard Y, et al (2016) Multi-criteria indices to evaluate the effects of repeated organic amendment applications on soil and crop quality. Agric Ecosyst Environ 232:165-178.

1060https://doi.org/10.1016/j.agee.2016.08.004

1061

1062Pattnaik S, Reddy MV (2010) Effects of urban organic wastes, their composts and vermicomposts on the growth traits of fenugreek (*Trigonella foenum-graecum* L.) and tomato (*Lycopersicum esculentum* Mill.) under field conditions. Dyn Soil Dyn Plant 4 (Special Issue 1) Global Science Books, 113-122.

1065

1066Pattnaik S, Reddy MV (2011) Accumulation and mobility of heavy metals in fenugreek (*Trigonella foenum-graecum* L.) and tomato (*Lycopersicum esculentum* Mill.) grown in the field amended with urban wastes, and their composts and vermicomposts. Int J Environ Technol Manag 14:147.

1069https://doi.org/10.1504/IJETM.2011.039268

1070

1071Peltre C, Gregorich EG, Bruun S, et al (2017) Repeated application of organic waste affects soil organic matter composition: Evidence from thermal analysis, FTIR-PAS, amino sugars and lignin biomarkers. Soil Biol Biochem 104:117-127.

1074https://doi.org/10.1016/j.soilbio.2016.10.016

1075

1076Peres G, Vandenbulcke F, Guernion M, et al (2011) Earthworm indicators as tools for soil monitoring, characterization and risk assessment. An example from the national Bioindicator programme (France).
1078Pedobiologia 54:S77-S87.

1079https://doi.org/10.1016/j.pedobi.2011.09.015

1080

1081Pirsaheb M, Khosravi T, Sharafi K (2013) Domestic scale vermicomposting for solid waste management. Int J Recycl Org Waste Agric 2:1-4.

1083https://doi.org/10.1186/2251-7715-2-4

1084

1085Rajpal A, Bhargava R, Sasi SK, Chopra AK (2012) On site domestic organic waste treatment through vermitechnology using indigenous earthworm species. Waste Manag Res 30:266-275.

1087https://doi.org/10.1177/0734242X11403798

1088

1089Roberts P, Jones DL, Edwards-Jones G (2007) Yield and vitamin C content of tomatoes grown in vermicomposted wastes. J Sci Food Agric 87:1957-1963.

1091https://doi.org/10.1002/jsfa.2950

1092
1093Rowen E, Tooker JF, Blubaugh CK (2019) Managing fertility with animal waste to promote arthropod

1094pest suppression. Biol Control 134:130–140.

1095https://doi.org/10.1016/j.biocontrol.2019.04.012

1096

1097Ruggieri L, Cadena E, Martínez-Blanco J, et al (2009) Recovery of organic wastes in the Spanish wine

1098industry. Technical, economic and environmental analyses of the composting process. J Clean Prod

109917:830–838.

1100https://doi.org/10.1016/j.jclepro.2008.12.005

1101

1102Sahariah B, Das S, Goswami L, et al (2020) An avenue for replacement of chemical fertilization under

1103rice-rice cropping pattern: Sustaining soil health and organic C pool via MSW-based vermicomposts.

1104Arch Agron Soil Sci 66:1449–1465.

1105https://doi.org/10.1080/03650340.2019.1679782

1106

1107Sajitha JP, Haripriya K, Mahesweri TU, Stella D (2007) Impact of organic nutrients on yield and

1108quality of garden bean. In: Chadha ML, Kuo G, Gowda CLL (eds) Proceedings of the 1st International

1109Conference on Indigenous Vegetables and Legumes Prospectus for Fighting Poverty, Hunger and

1110Malnutrition. Int Soc Horticultural Science, Leuven 1, pp 485–487

1111

1112Sampedro L, Domínguez J (2008) Stable isotope natural abundances (δ13C and δ15N) of the

1113earthworm *Eisenia fetida* and other soil fauna living in two different vermicomposting environments.

1114Appl Soil Ecol 38:91–99. https://doi.org/10.1016/j.apsoil.2007.10.008

1115Sherman RL, Appelhof M (2011) Small-scale school and domestic vermicomposting systems.

1116Vermiculture technology: Earthworms, organic wastes, and environmental management, CRC Press

1117LLC, Boca Raton pp 67–78.

1118

1119Sim EYS, Wu TY (2010) The potential reuse of biodegradable municipal solid wastes (MSW) as

1120feedstocks in vermicomposting. J Sci Food Agric 90:2153–2162.

1121https://doi.org/10.1002/jsfa.4127

1122

1123Singh A, Sharma S (2003) Effect of microbial inocula on mixed solid waste composting,

1124vermicomposting and plant response. Compost Sci Util 11:190–199.

1125https://doi.org/10.1080/1065657X.2003.10702127

1126
1127Singh RP, Singh P, Araujo ASF, et al (2011) Management of urban solid waste: Vermicomposting a
1128sustainable option. Resour Conserv Recycl 55:719-729.

1129https://doi.org/10.1016/j.resconrec.2011.02.005

1130

1131Soobhany N, Mohee R, Garg VK (2015a) Experimental process monitoring and potential of *Eudrilus*
1132*eugeniae* in the vermicomposting of organic solid waste in Mauritius. Ecol Eng 84:149-158.

1133https://doi.org/10.1016/j.ecoleng.2015.08.003

1134

1135Soobhany N, Mohee R, Garg VK (2015b) Recovery of nutrient from municipal solid waste by
1136composting and vermicomposting using earthworm *Eudrilus eugeniae*. J Environ Chem Eng 3:2931-
11372942. https://doi.org/10.1016/j.jece.2015.10.025

1138

1139Soobhany N, Mohee R, Garg VK (2017) A comparative analysis of composts and vermicomposts
1140derived from municipal solid waste for the growth and yield of green bean (*Phaseolus vulgaris*).

1141Environ Sci Pollut Res 24:11228-11239.

1142https://doi.org/10.1007/s11356-017-8774-2

1143

1144Suthar S (2007) Vermicomposting potential of *Perionyx sansibaricus* (Perrier) in different waste
1145materials. Bioresour Technol 98:1231-1237.

1146https://doi.org/10.1016/j.biortech.2006.05.008

1147

1148Suthar S (2009) Potential of *Allolobophora parva* (Oligochaeta) in vermicomposting. Bioresour
1149Technol 100:6422-6427.

1150https://doi.org/10.1016/j.biortech.2009.07.004

1151

1152Suthar S, Singh S (2008) Comparison of some novel polyculture and traditional monoculture
1153vermicomposting reactors to decompose organic wastes. Ecol Eng 33:210-219.

1154https://doi.org/10.1016/j.ecoleng.2008.04.004

1155

1156Tedesco DEA, Conti C, Lovarelli D, et al (2019) Bioconversion of fruit and vegetable waste into
1157earthworms as a new protein source: The environmental impact of earthworm meal production. Sci
1158Total Environ 683:690-698.

1159https://doi.org/10.1016/j.scitotenv.2019.05.226

1160

1161Tejada M, Benitez C (2020) Effects of different organic wastes on soil biochemical properties and
1162yield in an olive grove. Appl Soil Ecol 146: 103371. https://doi.org/10.1016/j.apsoil.2019.103371
1163

1164Tognetti C, Mazzarino MJ, Laos F (2008) Compost of municipal organic waste: Effects of different management practices on degradability and nutrient release capacity. Soil Biol Biochem 40:2290–2296.

1167https://doi.org/10.1016/j.soilbio.2008.05.006

1168

1169Tringovska I, Dintcheva T (2012) Vermicompost as substrate amendment for tomato transplant production. Sustain Agric Res 1. https://doi.org/10.22004/ag.econ.231364

1171

1172Tripathi G, Bhardwaj P (2004) Decomposition of kitchen waste amended with cow manure using an epigeic species (Eisenia fetida) and an anecic species (Lampito mauritii). Bioresour Technol 92:215–218.

1175https://doi.org/10.1016/j.biortech.2003.08.013

1176

1177Troschinetz AM, Mihelcic JR (2009) Sustainable recycling of municipal solid waste in developing countries. Waste Manag 29:915–923.

1179https://doi.org/10.1016/j.wasman.2008.04.016

1180

1181Varma VS, Kalamdhad AS (2016) Efficiency of rotary drum composting for stabilizing vegetable waste during rre-composting and vermicomposting. Environ Process- Int J 3:829–841.

1183https://doi.org/10.1007/s40710-016-0181-z

1184

1185Velecela S, Meza V, Garcia S, et al (2019) Microbial enrichment vermicompost under two production systems and its effects on radish (Raphanus sativus L.) production. Sci Agropecu 10:229–239.

1187https://doi.org/10.17268/sci.agropecu.2019.02.08

1188

1189Wani KA, Mamta, Rao RJ (2013) Bioconversion of garden waste, kitchen waste and cow dung into value-added products using earthworm Eisenia fetida. Saudi J Biol Sci 20:149–154.

1191https://doi.org/10.1016/j.sjbs.2013.01.001

1192

1193Yadav V, Karak T, Singh S, et al (2019) Benefits of biochar over other organic amendments: Responses for plant productivity (Pelargonium graveolens L.) and nitrogen and phosphorus losses. Ind Crops Prod 131:96–105.

1196https://doi.org/10.1016/j.indcrop.2019.01.045

1197
1198Yardim EN, Arancon NQ, Edwards CA, et al (2006) Suppression of tomato hornworm (Manduca
1199quinquemaculata) and cucumber beetles (Acalymma vittatum and Diabotrica undecimpunctata)
1200populations and damage by vermicomposts. Pedobiologia 50:23-29.

1201https://doi.org/10.1016/j.pedobi.2005.09.001

1202

1203Zhang DQ, Tan SK, Gersberg RM (2010) Municipal solid waste management in China: Status,
1204problems and challenges. J Environ Manage 91:1623-1633.

1205https://doi.org/10.1016/j.jenvman.2010.03.012