Anaerobic Degradation Pattern of Urban Solid Waste Components

Shwetmala1, Chanakya HN1, T.V. Ramachandra1,2

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1Centre for Sustainable Technologies, Indian Institute of Science, Bangalore 560012, India
2Centre for Ecological Sciences, Indian Insitute of Science, Bangalore 560012, India
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Citation: Shwetmala, Chanakya HN and Ramachandra T V, 2014. Anaerobic Degradation Pattern of Urban Solid Waste Components, In Waste Management and Resource Utilisation, Sadan K Ghosh (eds.), Pp 332-336, Oxford Publishing House, Kolkata.

The anaerobic digestion characteristics of ten specific types of the fermentable fractions commonly occurring in urban solid waste (USW) in Bangalore were examined. The rate of decomposition, the pattern of fit and extent and rate of biogas production from these potential feedstocks are analyzed and reported. More specifically, decomposition of vegetables wastes [cauliflower, onion, flat beans, radish and peas] and dominant fruit wastes [banana, sweet lime (Mosamby), orange, papaya and watermelon] were studied. Each of the fruits and vegetables were fermented singly and as mixtures by biological methane potential (BMP) assay to determine the process stability during anaerobic digestion. Typical mixtures of these vegetables and fruits were also fermented anaerobically to determine BMP. At periodic intervals samples of biogas produced were analyzed and their gas composition determined to monitor the decomposition rates and process health. Citrus fruits, orange and sweet lime had 95% and 94% of volatile solid, respectively, followed by peas shells (94%) and onion (92%). Among the ten feedstocks, flat beans, banana and citrus fruits (orange and Mosamby) showed a decomposition pattern similar to each other with a rapid initial decay pattern. The biogas production ranged from 205 to 616 ml/g of TS. Orange and sweet lime showed low gas production levels. Pea shells, flat bean, cauliflower and radish wastes showed a high gas production whereas banana peel had showed a moderate gas production level (c.465 ml/g TS). Such results provided an insight on the extent and rates of the major biodegradable organic fractions of urban solid waste in anaerobic degradation and likely process control required.

Keywords:Anaerobic degradation, Organic waste, BMP, Biogas, Decomposition rate.