Kosona Chriv

  • Adalidda

  • Cambodia, Phnom Penh, Phnom Penh

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Vermicomposting as an Alternative way of Biodegradable Waste Management for Small Municipalities

Authors: Aleksandra Sosnecka, Ma?gorzata Kacprzak, Agnieszka Rorat

The aim of the study was to assess the usefulness of vermicomposting as a method of bioconversion of organic wastes, inter alia sewage sludge, biodegradable fraction of municipal solid wastes and green wastes. Vermicomposting is a biological process in which earthworms are employed to cooperate with microorganisms in order to convert organic wastes into a valuable product. It is considered as a relatively low cost and environmentally-friendly method of waste treatment. Nevertheless, as each biotechnology, the process is limited to some physical, chemical and biological parameters. In this study, sewage sludge coming from medium-sized wastewater treatment plant was mixed with mown grass, sawdust and organic fraction of municipal wastes and vermicomposted for 5 weeks with Eisenia fetida and Eisenia andrei as main actors. The scope of the research was to 1) assess the influence of E. fetida and E.andrei composting earthworms on the physical and chemical properties of the product; 2) changes of concentration of selected heavy metals and their available forms in compost during the process, 3) the effects of substrates on earthworms survival and reproduction. Selected earthworm species had shown a high tolerance to the contaminants present in sewage sludge and a positive impact on the quality of the product was noted. Vermicomposting enhances decomposition of organic matter, leads to decrease in C/N ratio and pH, and changes the availability of some heavy metals and its total content in substratum. Experimental medium led earthworms to increase body weight due to the presence of large amount of organic matter, while the reproduction was importantly reduced. Vermicomposting can be considered as a method of treatment of solid wastes, mainly in the case of small municipalities.