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Ravindran B.,University Of Fort Hare | Contreras-Ramos S.M.,Environmental Technology Unit | Sekaran G.,CSIR - Central Leather Research Institute
Ecological Engineering | Year: 2015

Tanneries produce enormous quantities of solid waste including animal fleshing (ANFL) which is a major solid waste generated during pre-tanning operations of leather processing and needs to be disposed of in a safe and environmentally sound way. The aim of this study was to evaluate how the combination of earthworms and microorganisms could enhance the biodegradation of fermented tannery waste mixed with cow dung and leaf litter over a period of 25 days. In our previous study we focused on enzyme activity in fermented waste degradation while this current study revealed the significant role of microbial diversity and population in the Eudrilus eugeniae gut and in vermicompost manure. The maximum microbial population in both studies was recorded on day 21 of the vermicomposting process. Results in this study showed that substantial changes were observed with solid state ferment (SSF)>submerged state ferment (SmF)>control mixtures (p<0.05). The same trend was identified in earthworm gut enzyme activity. The phytohormones (indole 3-acetic acid [IAA], gibberellic acid [GA3], kinetin) were detected in all treatment vermicompost products. The germination index showed that the vermicomposts from all treatments had no phytotoxic effect on carrot seed (Daucus carota). The overall results confirmed that the microorganisms role were dominant in the vermicomposting process and that it is possible to produce rich manure from fermented tannery waste mixtures. © 2014 Elsevier B.V.

Rodriguez-Campos J.,Metrologic and Analytical Service Unit | Dendooven L.,CINVESTAV | Alvarez-Bernal D.,Regional Development Centre | Contreras-Ramos S.M.,Environmental Technology Unit
Applied Soil Ecology | Year: 2014

Earthworms can accelerate the removal of contaminants from soil. Earthworms change the physical and chemical properties of soil by mixing it with organic material and through their burrowing they improve aeration and render contaminants available for microorganisms. The presence of earthworms in contaminated soil indicate that they can survive a wide range of different organic contaminants, such as pesticides, herbicides, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and crude oil, at least when concentrations of the contaminant are not too high. The improvement of the soil due to their activity and the microorganisms in their digestive track can contribute to the accelerated removal of contaminants from soil, but sometimes their casts adsorb the pollutant so that its dissipation is delayed. There are limits, however, on how earthworms can be used to remediate soil, which will be discussed in this review. © 2014 Elsevier B.V.

Ravindran B.,CSIR - Central Leather Research Institute | Ravindran B.,Hong Kong Baptist University | Contreras-Ramos S.M.,Environmental Technology Unit | Wong J.W.C.,Hong Kong Baptist University | And 2 more authors.
Environmental Science and Pollution Research | Year: 2014

Animal fleshing (ANFL) is the predominant proteinaceous solid waste generated during processing of leather and it is confronting disposal problems. The aim of this study was to assess the potential of epigeic earthworm Eudrilus eugeniae to utilize and transform the fermented ANFL in the solid state (SSF) and submerged state (SmF) into a value added product along a low residence period (25 days). A total of six treatment units containing different waste mixture compositions were established. Fifty healthy and non-clitellated earthworms were introduced in three different treatment containers: control, SSF, and SmF (+worm). Another set of treatment mixtures (control, SSF, SmF) was established without earthworms (-worm) to compare the results. The products were characterized for physico-chemical, enzymatic analysis and seedling growth parameters to compare the differences in the process with and without earthworms. The changes observed in the analytical parameters were in the following order: SSF > SmF > control mixtures (p < 0.05). The vermicompost showed a significant reduction in heavy metals, total organic carbon and an increase in total Kjeldhal nitrogen as compared to the product untreated by earthworms. The maximum enzymatic activities were observed after 21 days of vermicomposting. The relative seed germination of vermicompost extracts were in the order of tomato (Lycopersicon esculentum) > green gram (Vigna radiata) > cucumber (Cucumis sativus) > bottle gourd (Lagenaria siceraria (Mol.) Standl.) and showed no phytotoxicity effects. The results indicated that the combination of both ANFL hydrolysis through fermentation and vermicomposting is a good alternative to the management of this kind of waste. © 2013 Springer-Verlag Berlin Heidelberg.

Dendooven L.,CINVESTAV | Alvarez-Bernal D.,Regional Development Centre | Contreras-Ramos S.M.,Environmental Technology Unit
Pedobiologia | Year: 2011

Contamination of soil with hydrocarbons occurs frequently. Restoring contaminated soils is costly and time consuming. Earthworms accelerate the removal of hydrocarbons as they burrow through soil by rendering contaminants available for microbial degradation, by feeding on the organic matter that harbour contaminants, and by improving soil structure and aeration. Polycyclic aromatic hydrocarbons (PAHs) are recalcitrant hydrocarbons that can contaminate the environment and can thus serve as models to study the factors that control the removal of petroleum from soil. The effect of earthworms on the removal of PAHs was reviewed. It was found that earthworms have the capacity to accelerate the removal of PAHs and their degradation products from soil. However, large numbers of earthworms are required, which might be expensive. Moreover, it may be difficult to provide sufficient organic material as feed while simultaneously maintaining high soil water content to allow burrowing. © 2011 Elsevier GmbH.

Ravindran B.,CSIR - Central Leather Research Institute | Sravani R.,CSIR - Central Leather Research Institute | Mandal A.B.,CSIR - Central Leather Research Institute | Contreras-Ramos S.M.,Environmental Technology Unit | Sekaran G.,CSIR - Central Leather Research Institute
Journal of Thermal Analysis and Calorimetry | Year: 2013

Animal fleshing (ANFL) is the main solid waste generated during manufacturing leather, which should be disposed friendly to the environment. The effect of epigeic earthworm Eudrilus eugeniae (with and without addition) to transform fermented ANFL in solid state (SSF) and submerged state (SmF) mixed with cow dung and leaf litter into value added product was studied in a vermibioreactor at low residence period (25 days). The products were characterised for pH and C:N ratio and the results were declined at the end of the treatment process with significant reduction in earthworm processed product. The maturity and the chemical changes of the final products were determined using spectroscopic analysis as UV-Visible Spectroscopy in which worm products (vermicompost) reached >5; this indicated that they were well humified. The FT-IR analyses results confirmed the complete mineralisation of polypeptides, polysaccharides, aliphatic methyl groups and lignin, and formation of a deep nitrate band in worm product compared to without worm processed product. Thermogravimetry (TG) and differential scanning calorimetry analyses were carried out in the initial mixture and final products to identify the mass loss and quantitative and qualitative information regarding physical and chemical changes occurred during composting process. The overall results indicated that the maturity of vermicompost (with worms) was in the order SSF > SmF > control. The results indicate that the combination of both fermentation and bacterial/vermicomposting (without worms/with worms) reduced the overall time required for production of well humified organic manure especially with worms. © 2011 Akadémiai Kiadó, Budapest, Hungary.

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