Effect on Growth of Earthworm and Chemical Parameters During Vermicomposting of Pressmud Sludge Mixed with Cattle Dung Mixture

Sustainable removal of nutrients (n and p) in a wastewater treatment plant, with eggshell (biocalcium)

Biological treatments have become insufficient to treat municipal wastewater with greater toxicity and excess nitrogen and phosphate species, thus affecting the organisms that consume the water. In this work, a process was implemented for the removal of nutrients through three stages: stage A, complete aeration (24 h, 43 months); stage B, decreased aeration (12 h, 17 months); and stage C, decreased aeration with biocalcium (12 h, 19 months). The addition of biocalcium from eggshell promoted the formation of flocks, which resulted in the removal of nitrites (61 %), nitrates (84 %), total nitrogen (57 %), total phosphorus (8.3 %), sedimentable solids (50 %), total suspended solids (69 %), BOD5 (76 %), helminth eggs (50 %) and fecal coliforms (54 %). The statistical analyses in the three stages indicated that there is a strong correlation between the concentration of fats and oils and the removal of sedimentable solids and total suspended solids, since these parameters were correlated by 97 and 89 %, respectively. Sedimentable solids were correlated with total suspended solids by 94 %, while nitrates and total nitrogen were correlated 92 %, which favors the removal of nutrients in wastewater. The increase in the concentration of nitrogen in the sludge in stage C generated a C:N ratio of 7.98. This ratio shows that the sludge is feasible for use as a mediator of soils and a biofertilizer because of the high contents of calcium, phosphorus and nitrogen. In addition, biocalcium promoted the precipitation of hydroxyapatite, struvite, calcite and quartz. In general, the three stages of the treatment contributed to the stabilization of the wastewater treatment plant (WWTP) in an efficient, economical, and safe way.

A Critical Review on the Vermicomposting of Organic Wastes as a Strategy in Circular Bioeconomy: Mechanism, Performance, and Future Perspectives

AbstractTo meet the current need for sustainable development, vermicomposting (VC), a natural, eco-friendly, and cost-effective technology, can be a wise selection for the bioconversion of organic wastes into value-added by-products. However, no one has tried to establish the VC technology as an economically sustainable technology by exploring its linkage to circular bioeconomy. Even, no researcher has made any effort to explore the usability of the earthworms (EWs) as a protein supplement while assessing the economic perspectives of VC technology. Very few studies are available on the greenhouse gas (GHG) emission potential of VC technology. Still, the contribution of VC technology towards the non-carbon waste management policy is not yet explored. In the current review, a genuine effort has been made to inspect the contribution of VC technology towards the circular bioeconomy, along with evaluating its capability to bioremediate the organic wastes generated from domestic, industrial, and agricultural premises. The potential of the EWs as a protein source has also been explored to strengthen the contribution of VC technology towards the circular bioeconomy. Moreover, the linkage of the VC technology to the non-carbon waste management policy has been comprehensively demonstrated by highlighting its carbon sequestration and GHG emission potentials during the treatment of organic wastes. It has been observed that the cost of food production was reduced by 60--70% by replacing chemical fertilizers with vermicompost. The implication of the vermicompost significantly lessened the harvesting period of the crops, thereby helping the farmers attain higher profits by cultivating more crops in a single calendar year on the same plot. Furthermore, the vermicompost could hold the soil moisture for a long time, lessening the water demand up to 30-40%, which, in turn, reduced the frequency of irrigation. Also, the replacement of the chemical fertilizers with vermicompost resulted in a 23% increment in the grapes' yield, engendering an extra profit of up to 110000 rupees/ha. In Nepal, vermicompost has been produced at a cost of 15.68 rupees/kg, whereas it has been sold to the local market at a rate of 25 rupees/kg as organic manure, ensuring a net profit of 9.32 rupees/kg of vermicompost. EWs embraced 63% crude protein, 5-21% carbohydrates, 6-11% fat, 1476 kJ/100 g of metabolizable energy, and a wide range of minerals and vitamins. EWs also contained 4.11, 2.04, 4.43, 2.83, 1.47, and 6.26  g/kg (on protein basis) of leucine, isoleucine, tryptophan, arginine, histidine, and phenylalanine, respectively, enhancing the acceptability of the EW meal (EWM) as the protein supplement. The inclusion of 3 and 5% EWM in the diet of broiler pullets resulted in a 12.6 and 22.5% increase in their feed conversion ratio (FCR), respectively after one month. Similarly, when a 100% fish meal was substituted by 50% EWM and 50% fish meal, the FCR and growth rate of Parachanna obscura were increased substantially. The VC of maize crop residues mixed with pig manure, cow dung, and biochar, in the presence of Eisenia fetida EWs, yielded only 0.003-0.081, 0-0.17, and 130.40-189.10 g CO₂-eq.kg^-1 emissions of CO₂, CH₄, and N₂O, respectively. Similarly, the VC of tomato stems and cow dung ensured 2.28 and 5.76 g CO₂-eq.kg^-1 CO₂ emissions of CH₄ and N₂O, respectively. Additionally, the application of vermicompost at a rate of 5 t/ha improved the soil organic carbon proportion and aggravated carbon sequestration. The land application of vermicompost improved micro-aggregation and cut down the tillage, reducing GHG emissions and triggering carbon sequestration. The significant findings of the current review suggest that VC technology potentially contributes to the concept of circular bioeconomy, substantially negotiates potential GHG emissions, and complies with the non-carbon waste management policy, reinforcing its acceptability as an economically sound and environmentally benevolent organic waste bioremediation alternative.

Potential of vermicomposting with mixtures of animal manure and vegetable leaves in the development of Eisenia foetida, microbial biomass, and enzymatic activity under semi-arid conditions

Vermicomposting is the bio-oxidation and stabilization of organic matter involving relationships between the action of earthworms and microorganisms and the activation and dynamics of several enzyme activities. Semi-arid farmers to make (extra) money and organic production, produce their vermicompost using plant residues and animal manure, but there is no information about the final product generated. Thus, this study aimed to analyze the potential of vermicomposting with mixtures of animal manure and vegetable leaves in the development of Eisenia foetida, microbial biomass, and enzymatic activity in the semi-arid region, Brazil. The experimental design applied was randomized block in a 6 × 4 factorial scheme with four replicates, with six treatments (mixtures of cattle manure, goat manure, cashew leaves, and catanduva leaves) and evaluated at four-time intervals (30, 60, 90, and 120 days of vermicomposting). The treatments were placed in polyethylene pots in the same site, environmental conditions, and residues proportions as used by farmers. The characteristics analyzed were the number of earthworms (NE), total earthworm biomass (TEB) and earthworm multiplication index (MI), microbial biomass carbon (MBC), and activities of enzymes β-glucosidase, dehydrogenase, alkaline and acid phosphatases. The cattle manure vermicomposted shows the highest average values observed for NE, MI, TEB, MBC, and enzymatic activity, regardless of the plant leaves mix. In general, the enzymes activities were found in the descending order of β-glucosidase > alkaline phosphatase > dehydrogenase > acid phosphatase. The maturation dynamics of vermicompost were characterized by a decline in the microbial population and number and biomass of earthworms in the substrate and consequently a decrease in new enzyme synthesis and degradation of the remaining enzyme pool. Microbial biomass and enzymatic activity were indicators for changes in the quality of vermicompost.

Reaction Kinetics in the Vermicomposting Process of Peach Waste

Peach is a fruit cultivated in temperate regions and its use generates waste composed of seeds and skin. Inadequate disposal of this waste generates an environmental impact; therefore, an alternative is to apply a vermicomposting degradation process. In this research, these four laboratory-scale reactors were used: RC (no earthworms), R1, R2, and R3 (50 earthworms each) to get mixtures in the following proportions of peach waste and load material (vegetable waste and eggshell): RC (50%-50%), R1 (50%-50%), R2 (60%-40%), and R3 (40%-60%). In addition, during this process, physicochemical parameters were analyzed (temperature, pH, humidity, total organic carbon (TOC), total nitrogen (TN), and carbon/nitrogen ratio (C/N)). For each mixture, the reaction order and rate constants were determined using mathematical models. After analysis of the reaction kinetics, the results showed that zero- and first-order reactions were best suited for the degradation of this waste in the vermicomposting process. The highest rates of degradation in the mixtures were for RC and R1, which means faster completion of the process, and consequently, smaller dimensions of the facilities necessary for vermicomposting. Thus, this research provides important information for the design of reactors that use similar substrates.

Co-composting with cow dung and subsequent vermicomposting improve compost quality of spent mushroom

In order to determine a feasible degrading process for spent mushroom (SMS) with high lignin content, the present work used cow dung (CD), SMS, and a mixture of CD and SMS as substrates and evaluated the effects of vermicomposting on the microflora and the quality of composting products. Bacterial (R² = 0.548, P = 0.001) and fungal (R² = 0.314, P = 0.005) community both were different between composting and vermicomposting. Vermicomposting and substrates affected enzyme activities indirectly by affecting ammonium, pH, total carbon, richness, and bacterial community composition. These results suggested that appropriate regulation of environmental factors may increase microbial activity. An increase in ion-exchange capacity (up to 139.8%), pH (6.9%), and nitrate (71.1%) and a decrease in total carbon (31.2%) and carbon/nitrogen ratio (32.1%) in vermicomposting indicated that earthworms could further improve product quality. Co-composting with CD and integrated subsequent vermicomposting efficiently promoted the maturity of SMS.

Vermicomposting: A Valorization Alternative for Corn Cob Waste

As vermicomposting has become a viable alternative for the valorization of organic waste; the objectives of this research were to (1) assess the feasibility of said process for corn cob waste (corn cobs and corn husks) and (2) evaluate the operation conditions for the biodegradation of different mixtures with load material (LM). LM did not include animal excreta as a nitrogen source, a practice widely used in a range of studies. The experiment consisted of an initial phase of pre-composting in order to obtain a partially stabilized substrate. Subsequently, four separate mixtures were made consisting of corn cob waste mixed with consistent load material (LM) containing vegetable waste and eggshells (CR, M1, M2, M3) to obtain a balance substrate able to facilitate degradation using Eisenia fetida earthworms. The following parameters were analyzed during the control process: temperature, pH, humidity, organic material (OM), total organic carbon (TOC), total nitrogen (TN) and carbon/nitrogen (C/N) ratio. The analysis of the final values of the stabilized mixtures showed that vermicomposting is indeed a feasible alternative for the degradation of corn cob waste for use as a soil improver.

Dataset of cow manure by earthworm bio-composting process

Earthworm bio-composting is an environmentally friendly way of processing agricultural organic waste, especially cow manure. In order to observe the temperature, humidity and conductivity of cow manure during the biological composting process of earthworms, a composting data collection system was designed to collect the above data. The experiment was carried out in an earthworm breeding farm in Changqing District, Jinan City, and lasted for 50 days, from October 21, 2020 to December 10, 2020. The experiment data can be used for data comparison with conventional composting, and can also provide a reference for the exploration of the earthworm composting process.

Centrality of cattle solid wastes in vermicomposting technology - A cleaner resource recovery and biowaste recycling option for agricultural and environmental sustainability

The current review reports the importance and significance of cattle solid waste in vermicomposting technology concerning biowaste pollution in the environment. Needy increasing population evokes livestock production resulting in the massive generation of livestock wastes, especially cattle dung. Improper disposal and handling of biowastes originating from agriculture, industries, forests, rural and urban areas lead to nutrient loss, environmental pollution and health risks. Among the organic waste disposal methods available, vermicomposting is regarded as an environmentally friendly technology for bioconversion of agricultural, industrial, rural and urban generated organic solid wastes which are serving as reservoirs of environmental pollution. In vermicomposting of organic wastes, cattle dung plays a central role in mineralization, nutrient recovery, earthworm and microbial activity leading to vermifertilizer production. Even though the vermicomposting studies use cattle dung invariably as an amendment material, its importance has not been reviewed to highlight its central role. Hence, the present review mainly emphasizes the key role played by cattle dung in vermicomposting. Vermiconversion of cattle dung alone and in combination with other biowaste materials of environmental concern, mechanisms involved and benefits of vermicompost in sustainable agriculture are the major objectives addressed in the present review. The analysis reveals that cattle dung is indispensable amendment material for vermicomposting technology to ensure agricultural and environmental sustainability by reducing pollution risks associated with biowastes on one hand, and nutrient-rich benign vermifertilizer production on the other hand.

Nutrient recovery and vermicompost production from livestock solid wastes with epigeic earthworms

The aim of this work was to study nutrient recovery and vermicompost production from livestock solid wastes of indigenous and exotic cow breeds with epigeic earthworms. Fourteen days pre-decomposed dung of Vechur native (CD1) and exotic Jersey (CD2) breeds were vermicomposted with Perionyx excavatus and Eudrilus eugeniae for 45 days (Cycle I) and 90 days (Cycle II) including respective controls without earthworms. Vermicomposts from CD1 and CD2 substrates during Cycle I and II showed increase in NPK, Ca and micro-nutrients (P < 0.05); whereas, pH, total organic carbon, C/N and C/P ratios disclosed decrease (P < 0.05) over initial levels for both the earthworms. E. eugeniae was found efficient in vermicomposting cattle solid wastes in 45 days and CD1 yielded nutrient rich vermicompost. The study concludes that Cycle I is suitable for nutrient recovery and vermicompost production, in addition to mass multiplication of earthworms in Cycle II.

Earthworms and vermicompost: an eco-friendly approach for repaying nature's debt

The steady increase in the world's population has intensified the need for crop productivity, but the majority of the agricultural practices are associated with adverse effects on the environment. Such undesired environmental outcomes may be mitigated by utilizing biological agents as part of farming practice. The present review article summarizes the analyses of the current status of global agriculture and soil scenarios; a description of the role of earthworms and their products as better biofertilizer; and suggestions for the rejuvenation of such technology despite significant lapses and gaps in research and extension programs. By maintaining a close collaboration with farmers, we have recognized a shift in their attitude and renewed optimism toward nature-based green technology. Based on these relations, it is inferred that the application of earthworm-mediated vermitechnology increases sustainable development by strengthening the underlying economic, social and ecological framework.

Enriched pressmud vermicompost production with green manure plants using Eudrilus eugeniae

Vermicomposting of pressmud with cow dung and nitrogenous green manures (Gliricidia sepium and Leucaena leucocephala) was carried out using Eudrilus eugeniae (50 days). The reduction in pH, total organic carbon, C/N ratio, water-soluble organic carbon (C_ws)/N_org and C/P ratios, and a pronounced increase in NPK contents and microbial population in vermicompost were observed. An enhanced TKN of 3.80% and 3.45% was recorded in vermicomposts of pressmud + cow dung + L. leucocephala (2:1:1) and pressmud + cow dung + G. sepium (2:1:1) respectively. The C/N and C_ws/N_org ratios in vermicompost ranged from 11.86 to 16.66 and 0.53 to 1.33, respectively. The activity of dehydrogenase, urease, acid and alkaline phosphatase declined towards the end, indicating the progression of vermicompost maturity. The pressmud and green manure substrates promoted more biomass of E. eugeniae, while cow dung with green manure combination favored reproduction. The amendment of cow dung and green manure plants to pressmud (2:1:1 ratio) results in nutrient-enriched vermicompost production.

Analysis and advanced characterization of municipal solid waste vermicompost maturity for a green environment

Rapid demographic expansion along with increasing urbanization has aggravated the problem of solid waste management. Therefore, scientists are seeking waste management methods that are eco-friendly, cost effective and produce immediate results. In the developing world, municipal solid waste (MSW) contains mostly organic substances, therefore vermicomposting could be a better and cost-effective option for waste management. In this study, vermicomposting of organic portion of MSW with cow dung (additive) was performed using Eisenia fetida. The results showed significant (p < 0.001) decline in pH (13.17%), TOC (21.70%), C: N (62.53%) and C: P (57.66%) ratios, whilst total N (108.9%), P (84.89%) and K (21.85%) content increased (p < 0.001) in matured vermicompost. Different enzymatic activities declined during termination phase of vermicomposting experiment with maximum decrease of 41.72 (p = 0.002) and 39.56% (p = 0.001) in protease and β-glucosidase, respectively. FT-IR, TGA, DSC and SEM studies suggested that final vermicompost was more stabilized as compared to initial waste mixture, characterized by reduced levels of aliphatic materials, carbohydrates and increase in aromatic groups possibly due to biosynthesis of humic substances. Both, the conventional (physicochemical and enzyme activity) and advanced techniques depict maturity and stability of the ready vermicompost. However, FT-IR, TGA, DSC and SEM were proved to be more promising, fast and reliable techniques over conventional analyses.

Spent mushroom substrate and cattle manure amendments enhance the transformation of garden waste into vermicomposts using the earthworm Eisenia fetida

Garden wastes (GW) having high lignin contents could hinder the growth of earthworms and microorganisms in vermicomposting. This study investigated the Eisenia fetida-based vermicomposting of GW mixed with cattle manure (CM) and/or spent mushroom substrate (SMS) at different ratios of GW alone (control), 3:1 GW:SMS, 1:1 GW:SMS, 3:1 GW:CM, 1:1 GW:CM and 2:1:1 GW:SMS:CM to promote earthworm growth and improve the final vermicompost quality. In general, treatments with the addition of SMS and/or CM increased the survival rate, biomass, cocoon and juvenile numbers of E. fetida compared to the control. The addition of SMS and/or CM also significantly increased the activities of dehydrogenase, cellulase, urease, and alkaline phosphatase compared to the control. Furthermore, the addition of SMS and/or CM facilitated the decomposition of organic matter, cellulose and lignin, increased nutrient (N, P and K) concentrations, and accelerated nitrification compared to the control. The addition of SMS and CM led to greater chemical changes of the substrate compared to control. Heavy metal concentrations were increased in the final vermicomposts comparatively to the initial materials, but none of them exceeded the permissible limits. The highest germination index of Chinese cabbage and tomato seeds were both observed in the treatment of 2:1:1 GW:SMS:CM which reached 146.9 and 148.1. Overall, the 2:1:1 GW:SMS:CM treatment had the highest growth and reproduction rates of E. fetida, higher percentage degradation of organic matter, cellulose and lignin, as well as the best quality of the final vermicompost.

Using Earthworms Eisenia fetida (Sav.) for Utilization of Expansive Littoral Plants Biomass

This paper presents the results of the process of vermicomposting waste biomass of littoral plants Typha latifolia, Iris pseudacorus, Ceratophyllum demersum in vermireactors, with the use of earthworms Eisenia fetida. It was observed that E. fetida may be used for rapid utilization of pure I. pseudacorus and C. demersum waste, but using the technology presented in this paper and the assumed observation time, it was not possible to recycle T. latifolia waste. Vermicomposts obtained were characterized by higher N, P, K, Ca, and Mg content compared to the initial plant biomass. The content of Cu, Mn, Zn, Cd, and Pb in vermicomposts did not exclude their application as a fertilizer. During vermicomposting of all littoral plants, the earthworm population was maintained up to day 70 of the experiment, with a slight decrease in their number (on average by 6%, p > 0.05), and since day 35, a significant loss in earthworm biomass was observed. The greatest loss of mean sum of biomass (49%, p < 0.05) was noted in a group of earthworms utilizing T. latifolia. The earthworms reproduced, with the greatest mean number (and the sum of biomass) of cocoons observed in a group of earthworms processing C. demersum. These values were greater by 32% and 38% respectively (p < 0.05), for the aforementioned characteristics of cocoons produced in the remaining experimental groups.

Recycling of lignocellulosic waste as vermicompost using earthworm Eisenia fetida

Present study aimed to evaluate the vermicomposting of lignocellulosic wastes employing Eisenia fetida earthworms. The study examined the effectiveness of vermicomposting for 105 days by mixing lignocellulosic waste (LW) with cattle manure (CM) in five different proportions. Results revealed that TOC and C/N ratio decreased gradually till end and in vermicomposts varied between 268-320 g/kg and 12.26-16.85, respectively. Nutrient content (NPK) in the vermicomposts increased with time in all the mixtures. Heavy metals' content also increased in vermicomposts and benefit ratio for heavy metals ranged between 0.06 and 5.1. Increase in earthworm biomass (22.38-39.64 g) and reproduction (21.27-31.60 hatchlings/worm) was also satisfactory in all the waste mixtures. Based on results, it can be inferred that lignocellulosic waste can successfully be converted into good quality manure employing earthworms.

Biotransformation of bakery industry sludge into valuable product using vermicomposting

The aim of present work was to evaluate periodic changes in bakery industry sludge during vermicomposting. Six different blends of cow dung (CD) and bakery industry sludge (BIS) containing 10 to 50% of BIS were assessed in this study. Changes in physico-chemical parameters were evaluated at 21 days interval up to 105 days. Earthworms significantly increased NPK content and EC, while decreased pH, TOC and C: N ratio of BIS. After vermicomposting, TKN, TAP and TK contents increased 2.0-3.5, 1.2-1.9 and 1.2-1.4 times, respectively as compared to initial blends. A significant reduction (65.4-83.5%) in C: N ratio was observed in all blends. The concentrations of metals were found to be higher in the vermicomposts as compared initial blends. It was inferred that bakery industry sludge spiked with cow dung can be biotransformed into valuable manure employing earthworms.

Comparative analysis of vermicompost quality produced from rice straw and paper waste employing earthworm Eisenia fetida (Sav.)

Present study was undertaken to investigate the vermicomposting of two different organic wastes (rice straw and paper waste) employing, Eisenia fetida. Nine feedstocks were prepared with different ratios of wastes using cow dung as bulking substrate. After pre-composting, worms were allowed to feed on different feedstocks for 105 days under laboratory conditions. The results showed that NPK content was higher in the vermicompost. Heavy metal content was also higher in the vermicomposts. Whereas total organic carbon and C:N ratio were lower after vermicomposting, by 17.38-58.04% and 19-102% respectively. SEM images revealed changes in the morphology of vermicompost. Earthworm growth and reproduction was significant in different feedstocks except one containing 50% rice straw depicting that this ratio is not suitable for the earthworms. Results further demonstrated that proportion of bulking substrate affect the earthworm growth and reproduction.

Evaluation of pilot-scale in-vessel composting for Hanwoo manure management

The study investigated the effect of in-vessel composting process on Hanwoo manure in two different South Korea regions (Pyeongchang and Goechang) with sawdust using vertical cylindrical in-vessel bioreactor for 42days. The stability and quality of Hanwoo manure in both regions were improved and confirmed through the positive changes in physico-chemical and phytotoxic properties using different commercial seed crops. The pH and electrical conductivity (EC, ds/m) of composted manure in both regions were slightly increased. At the same time, carbon:nitrogen (C:N) ratio and ammonium nitrogen:nitrate nitrogen (NH₄⁺-N:NO₃^--N) ratio decreased to 13.4-16.1 and 0.36-0.37, respectively. The germination index (GI, %) index was recorded in the range of 67.6-120.9%, which was greater than 50%, indicating phytotoxin-free compost. Although, composted manure values in Goechang region were better in significant parameters, overall results confirmed that the composting process could lead to complete maturation of the composted product in both regions.

Amelioration and degradation of pressmud and bagasse wastes using vermitechnology

This study evaluated the amelioration of pressmud (PM) and bagasse (BG) wastes by the vermiremediation process. The wastes were spiked with cattle dung (CD) in different concentrations to find out the best proportion supporting maximum earthworm growth and nutrients availability. The highest growth rate was observed in PMBG₅₀ (282.2mg/d/worm) feed mixture. Response surface design of earthworm growth parameters enumerated best concentration of wastes in CD with maximum value of 21.81% for earthworm number, 30.86% for earthworm weight, 27.09% for cocoons, 29.71% for hatchlings and 34.0% for hatchlings weight. Vermicomposting enhanced nutrient parameters like pH (6-8%), total kjeldahl nitrogen (19-48%), total phosphorus (9-67%), total calcium (13-111%), while decrease in total organic carbon (14-32%), electrical conductivity (21-30%), C:N ratio (36-51%), total potassium (9-19%) and total sodium (3-21%). Heavy metals in the final products were found to be under safe limits. SEM micrographs were more fragmented which indicated maturity and stability.