Search

The intervention management strategy to mitigate ecotoxicity in a heavy metal (HM)-contaminated soil was evaluated through a new soil remediation technique trial by using extracts of composts and vermicomposts from Municipal Solid Waste (MSW). The MSW composts and vermicomposts which were >9.423 mm in size referred as coarse and those Co > Cu > Cd > Cr > Zn. Results showed that treatments with compost-extracts from ground samples removed 90.83% Ni, 90.45% Co, 84.64% Cu, 79.01% Cd, 76.85% Cr and 76.77% Zn from the contaminated soil. On the contrary, treatments with vermicompost-extracts from ground samples caused moderately higher reduction in Ni (91.52%), Co (90.69%), Cu (85.18%), Cd (81.42%), Cr (79.06%) and Zn (79.02%). The remediation factors (RFs) of the HMs from the ground vermicompost-extracts can be classified in the order: Ni (8.06–10.98) > Co (8.28–10.61) > Cu (5.44–5.76) > Cd (2.82–4.41) > Zn (2.93–3.77) > Cr (1.37–2.11) whilst a lower RF value was obtained for the remediation treatments from the ground compost-extracts. Yet, in contrast of using compost-extracts from both coarse and ground samples to remediate metalliferous soil, data analysis revealed that vermicompost-extracts were more proficient in the mitigation of the concentration of HMs.

This experimental work aimed to assess the physicochemical properties and quality parameters in different substrates during composting of organic constituents of Municipal Solid Waste (OCMSW) for a period of 40 days. Three different runs were set up respectively in three 244 L in-vessel systems and designated as R1, R2 and R3. R1 depicted the food waste mix; R2 represented the paper waste mix and R3 for the yard waste mix. pH values in the three runs showed an analogous varying range and decreased to 7.4–7.5. The net degradation of the composting matrix in respect of volatile solids diminution was 77.71%, 61.19%, 62.26% for R1, R2 and R3 respectively. The data of Carbon to Nitrogen (C/N) ratios demonstrated a general decrease of 22.8% − 28.1% in final mixtures. R2 had the highest water holding capacity of 4.71 ± 0.64 (471%) among others. The final nutrient contents P, K, Ca, Mg and Na showed an increase as compared initially. The experimental analysis pointed out that different element influenced compost quality and the quality of the end product can be evaluated by several parameters in order to ensure its safe use in the cultivation of crops. Results demonstrated that composting of OCMSW as an appropriate management practice for the remediation of toxic heavy metals. There is a great scope for an extensive application of composting technology on a nationwide basis and the qualitative information reported on the compost quality parameters may permit its utilization by the public.

The use of composts or vermicomposts derived from organic fraction of Municipal Solid Waste (OFMSW) brought about certain disagreement in terms of high level of bacterial pathogens, thereby surpassing the legal restrictions. This preliminary study was undertaken to compare the evolution of pathogenic bacteria on OFMSW compost against vermicompost (generated by Eudrilus eugeniae ) with promises of achieving sanitation goals. Analysis to quality data showed that OFMSW vermicomposting caused a moderately higher reduction in total coliforms in contrast to composting. E. coli in OFMSW composts was found to be in the range of 4.72–4.96 log 10 CFU g −1 whilst on a clear contrary, E. coli was undetectable in the final vermicomposts (6.01–6.14 logs of reduction) which might be explained by the involvement of the digestive processes in worms' guts. Both OFMSW composts and vermicomposts generated Salmonella -free products which were acceptable for agricultural usage and soil improvement. In comparison to compost, the analysis of this research indicated that earthworm activity can effectively destroy bacterial pathogenic load in OFMSW vermicomposts. But still, this study necessitates extra research in order to comprehend the factors that direct pathogenic bacteria in vermicomposting and earthworm-free decomposition systems.

Waste management strategies for organic residues, such as composting and vermicomposting, have been implemented in some developed and developing countries to solve the problem of organic solid waste (OSW). Yet, these biological treatment technologies do not always result in good quality compost or vermicompost with regards to sanitation capacity owing to the presence of bacterial pathogenic substances in objectionable concentrations. The presence of pathogens in soil conditioners poses a potential health hazard and their occurrence is of particular significance in composts and/or vermicomposts produced from organic materials. Past and present researches demonstrated a high-degree of agreement that various pathogens survive after the composting of certain OSW but whether similar changes in bacterial pathogenic loads arise during vermitechnology has not been thoroughly elucidated. This review garners information regarding the status of various pathogenic bacteria which survived or diffused after the composting process compared to the status of these pathogens after the vermicomposting of OSW with the aim of achieving sanitation goals. This work is also indispensable for the specification of compost quality guidelines concerning pathogen loads which would be specific to treatment technology. It was hypothesized that vermicomposting process for OSW can be efficacious in sustaining the existence of pathogenic organisms most specifically; human pathogens under safety levels. In summary, earthworms can be regarded as a way of obliterating pathogenic bacteria from OSW in a manner equivalent to earthworm gut transit mechanism which classifies vermicomposting as a promising sanitation technique in comparison to composting processes.

The study was to assess and compare the redistribution of nutrients content (N, P, K, Ca, Mg, and Na) during the composting and vermicomposting processes of organic components of Municipal Solid Waste (MSW) for a period of 10 weeks. Six experiments were set up in which three experiments were for the in-vessel composting (S1, S2 and S3) which acted as controls and the other three were for the vermibin vermicomposting (S4, S5 and S6) using Eudrilus eugeniae as earthworm specie. The organic fraction of MSW was evaluated for nutrient contents and the composts from the in-vessels systems expressed a significant increase in total N (except for S1), P, K, Ca, Mg and Na. Similarly from the vermibins, all vermicomposting processes demonstrated an increase in these nutrients. Vermicomposting processes demonstrated a higher increase in P (67.2–87.5%), K (24.9–45.8%), Mg (12.2–63.8%) and Na (30.2–40.5%) than composting processes which might be possibly owing to the bacterial and faecal activity of earthworm gut enzymes resulting in mobilization and mineralization of these nutrients. Data suggested that the feasibility of inoculated earthworms to enhance the nutrient profile in MSW compared to the simple composting process might contribute to differentiate between vermicomposts and composts in their effects on plant growth.

This study was undertaken to assess the experimental process monitoring during the vermicomposting of organic solid waste (OSW) utilizing Eudrilus eugeniae as earthworm species. Three mixes for the vermicomposting of OSW were set up separately in three 244 L vermibins and denoted as M1, M2 and M3. M1 represented the food waste mix; M2 represented the paper waste mix and M3 for the yard waste mix. An increase in wet bulk density with a maximum value of 424.0 ± 8.7 kg/m3, 573.3 ± 9.9 kg/m3 and 349.7 ± 6.4 kg/m3 was noted for M1, M2 and M3, respectively. The net degradation of the vermicompost pile in terms of volatile solids reduction was 80.58% for M1, 61.03% for M2 and 77.51% for M3. The value of C:N ratios depicted an overall decrease of 41.5–48.4% in the final mixtures. The growth rate of E. eugeniae in the vermicomposting mixes was 3.33 g day−1, 3.47 g day−1 and 1.67 g day−1 for M1, M2 and M3 respectively and the mean size of the cocoons produced was 4.26 mm × 2.82 mm. Results suggested vermicomposting as an appropriate technology for bioremediation of heavy metals from OSW. Data implied that there is a huge scope for the implementation of vermicomposting technology on a countrywide basis by the scientific community of Mauritius considering the quantities and properties of OSW generated.

This article reviews the current status of waste management in Small Island Developing States (SIDS) and the challenges that are faced in solid waste management. The waste generation rates of SIDS were compared within the three geographic regions namely Caribbean SIDS, Pacific SIDS and Atlantic, Indian Ocean, Mediterranean and South China (AIMS) SIDS and with countries of the Organisation for Economic Co-Operation and Development (OECD). Only Pacific SIDS had a waste generation rate less than 1kg/capita/day. The waste generation rates for the three SIDS regions averaged 1.29kg/capita/day while that for OECD countries was at a mean value of 1.35kg/capita/day. The waste compositions in the different SIDS regions were almost similar owing to comparable consumption patterns while these differed to a large extent with wastes generated in OECD countries. In SIDS, the major fraction of MSW comprised of organics (44%) followed by recyclables namely paper, plastics, glass and metals (total: 43%). In contrast, MSW in OECD countries consisted mainly of recyclables (43%) followed by organics (37%). This article also reviewed the other functional elements of the waste management systems in SIDS. Several shortcomings were noted in the process of waste collection, transfer and transport namely the fact of having outdated collection vehicles and narrow roads which are inaccessible. Among the waste management practices in SIDS, waste disposal via landfilling, illegal dumping and backyard burning were favoured most of the time at the expense of sustainable waste treatment technologies such as composting, anaerobic digestion and recycling.

This is the first-ever study of its kind for an extensive assessment and comparison of maturity indexes between compost and vermicompost that have been derived from Municipal Solid Waste (MSW). The spectroscopic (Fourier transform infrared spectroscopy: FT-IR), thermogravimetric analysis (TG), differential scanning calorimetry (DSC) and structural characterization (scanning electron microscope: SEM) were recorded. FT-IR spectra showed an increase in conversion of polysaccharides species and aliphatic methylene groups in vermicompost compared to compost as depicted from the variation of the intensity of the peaks. TG curves of final vermicompost showed a much lower mass loss when compared to compost, indicating higher stability in feedstock. SEM micrographs of the vermicompost reflected strong fragmentation of material than composts which revealed the extent of intra-structural degradation of MSW. These findings elucidate on a clear comparison between composts and vermicomposts in terms of maturity indexes for soil enhancement and in agriculture as organic fertilizer.

The safe disposal of organic solid waste (OSW) has been regarded as utmost concern in this period of green economy and the concept of producing high quality fertilizers with an enriched nutrient content is at present identified prospectively in many countries. When OSW are improperly disposed, considerable amounts of nutrients which are locked in the OSW are reduced or lost. These valuable nutrients which are lost might be recuperated through suitable biochemical technologies and employed as nutrient-rich fertilizers in agricultural fields for maintaining soil fertility. This work aimed to review macro-nutrients (N, P, K) and micro-nutrients (Ca, Mg, Na, Fe, Cu, Mn, Zn, B, Mo, S) recycling during biochemical conversion technologies e.g. composting and vermicomposting of OSW for the production of fertilizer. This work also elucidates the possible ways of enriching the nutrient content in vermicompost, the effects of possible mechanisms on earthworms linking to nutrients enrichment and the quality assessment of composts and vermicomposts in terms of nutrient content. Generally, it would appear that vermicomposts can have ‘‘added-value’’ characteristics since vermicomposting of OSW could efficiently amplify the nutrients content and vermicomposts could be inferred as a superior organic fertilizer with high nutritional content of agronomic importance in contrast to composts. The high nutrient content in vermicompost could be explicated by earthworm gut-borne microorganisms which mixed with organic matter (OM) during their passage in the intestine and those microorganisms consecutively have a vital role in the biochemical alterations of nutritive elements. This review recommends the importance of obtaining a comprehensive insight on the earthworm activity entailed in vermitechnology, especially the mechanisms they accomplish for the nutrients enrichment. Conclusively, the need for further scientific research aimed at outlining Mg and Na metabolisms by earthworm mechanism and also other trace elements (Fe, Cu, Mn, Zn, B, Mo, S) in vermicomposting processes is greatly recommended which will thus provide a meaningful direction for future study.

This work was conducted to evaluate and compare the responses of Phaseolus vulgaris to three types of composts and vermicomposts derived from municipal solid waste (MSW). Different amendment rates were used and evaluated for their effect on germination, growth, and marketable yield. MSW-derived vermicomposts and composts were substituted into mineral brown-earth soil, applied at rates of 0 (control), 10, 20, 30, 40, 50, and 100% (v/v) in plastic pots of 7.2-L capacity. Green beans which are grown in 40% vermicompost/soil mixtures and compost/soil mixtures yielded 78.3–89.5% higher fruit weights as compared to control. Results showed that MSW vermicomposts consistently outperformed equivalent quantities of composts in terms of fruit yield, shoot, and root dry weights, which can be attributed to the contributions of physicochemical properties and nutrients content (N, P, and K) in the potting experiments. Consequently, it seemed likely that MSW vermicompost provided other biological inputs such as plant growth regulators (PGRs) and plant growth hormones (PGHs), which could have a considerably positive effect on the growth and yields of P. vulgaris as compared to composts. More in-depth scientific investigation is required in order to identify the distinctive effects and the exact mechanisms of these PGRs in MSW vermicomposts which influenced plant growth responses.

This study was undertaken to have comparative assessment of heavy metals content during composting and vermicomposting processing of Municipal Solid Waste (MSW). Six scenarios were set up in which three experiments were for composting (controls) denoted as S1 for food waste, S2 for paper waste and S3 for yard waste and the corresponding replicates for vermicomposting processes were S4, S5 and S6. Vermicomposting caused significant reduction in Cd (43.3-73.5%), Cr (11.3-52.8%), Cu (18.9-62.5%), Co (21.4-47.6%), Zn (34.6%) and Ni (19.9-49.6%) compared to composting which showed a progressive increase. Addition of worms did not show any effect on Fe and Mn, most probably from the genesis of organic-bound complexes. The efficacy of utilizing Eudrilus eugeniae was indicated by the high values of bioconcentration factors (BCFs) which were in the order of Cd>Ni>Cu>Co>Cr>Zn and the increase amount of these metals in the earthworms' tissue after the vermicomposting processes. Different values of BCFs were obtained for different heavy metals and this accounted that earthworms exert different metabolic mechanisms. Regression analysis of the reduction percentages (R) in relation to BCF showed that RCdtot.S6, RCrtot.S5 and RCutot.S6 were significantly correlated with BCFCd.S6, BCFCr.S5 and BCFCu.S6 respectively. Thus, in comparison to simple composting processes, data analysis suggested the feasibility of inoculating E. eugeniae to MSW in order to mitigate the content of toxic heavy metals.

This study was to assess the effect of new species of earthworms; Pheretimoid Spp.on vermicomposting and compare the quality of vermicompost against compost produced from the same mix ratio of shredded office paper (SOP) together with grass clippings (GC) and cow manure (CM). Two composting experiments were setup in rotary drum composters namely: 1) composting of SOP, GC and CM followed by vermicomposting (denoted as reactor VC); 2) composting of SOP, GC and CM without the addition of worms (denoted as reactor C). The composting mixes consisted of a ratio of 1:4.3:3 on a mass basis of SOP, GC and CM respectively. When a temperature of 28–30°C was reached in reactor VC, adult Pheretimoid Spp. were introduced for the vermicomposting experiment. Copper and lead were found to be 44.8 mg/kg and 21.2 mg/kg, respectively for VC whereas a concentration of 51.2 mg/kg and 27.0 mg/kg were obtained in C. Cadmium was undetectable in vermicompost whilst 0.945 mg/kg of Cd was present in the compost. Analysis of the total nutrients content suggest that the amount of nutrients present (N, P, K, Ca, Mg) in VC was relatively higher than that of C with an increase of 0.05% to 0.23%.