engleski

Biodegradation of simulated leachate from tobacco dust waste by indigenous microorganisms

Landfill leachate is defined as the aqueous effluent generated as a consequence of rainwater percolation through wastes, biochemical processes in waste's cells and the inherent water content of wastes themselves. Biological processes are often used for the removal of the bulk of leachate containing high chemical oxygen demand (COD) concentrations primarily due to their higher reliability, simplicity and cost effectiveness. Tobacco waste poses an important environmental problem as some main components of tobacco waste are harmful and toxic. Present compounds could constitute a potential risk to the quality of receiving water bodies, when leachates are released into the environment, because they are usually toxic, resistant to environmental degradation and have other characteristics which make them hazardous to the environment. Conventional activated sludge is suboptimal for tobacco wastewater treatment. Aerobic biological processes based on suspended-growth biomass have been widely studied and adopted. Activated sludge is a process for biodegrading organic contaminants in wastewater using a mixed population of microorganisms, which can degrade organic compounds to carbon dioxide and sludge under aerobic conditions. During the process of biodegradation microorganisms present in an activated sludge and suspended solids from wastewater have the ability to interconnect into larger or smaller clusters, called flocs of activated sludge. The ability of microorganisms to form flocs is vital for the activated sludge treatment of leachate. Particles present in water play an important role in all issues related to water quality and treatment. The aim of this work was to study the efficiency of biodegradation of organic pollutants of simulated leachate from tobacco dust waste under batch conditions by indigenous microorganisms. Further, the purpose of this work was also to mathematically describe the process in order to enable better understanding of biological process of degradation of organic matters from wastewater and leachate. During the experiments, toxicity test with Vibrio fischeri, pH value, dissolved oxygen (DO), COD, mixed liquor volatile suspended solids (MLVSS), concentration of NH4-N and NO3-N have been monitored. The microscopic analyses were conducted to monitoring morphology of activated sludge. The obtained results have shown that by process of biodegradation toxicity of leachate from tobacco dust waste decreased from 11533 mg dm-3 to 2999 mg dm-3. Leachate samples were found to be biodegradable with more than 72 % COD removal. The pH values and DO were in the range from 5.97 to 9.18 and between 1.40 mg dm-3 to 8.89 mg dm-3. The concentration of NO3-N was decreased by 90.84 % and resulted to increase in concentration of NH4-N by 80.06 %. The MLVSS values ranged in optimal limits and varied from 4.76 g dm-3 to 7.50 g dm-3.

biodegradation; leachate; tobacco waste

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