engleski

The effect of season on microbial activity during composting of biodegradable municipal waste

The growing world population and the resulting higher consumption of goods and services have driven a rapid increase of organic wastes which represents a valuable organic recyclable resource. Climate-friendly technologies, such as composting, need to be adopted to ensure a sustainable future environment. The biological cycling of nutrients is indispensable for life and is mediated through microorganisms. An active microbial community consists of different microorganisms that possess different metabolic activities, and their metabolic paths lead to significant changes in the physical and chemical parameters of the composting substrate. The objectives were to investigate the effect of seasonal variation of biodegradable fraction from municipal waste on microbial activity during composting. During 21 days of composting of biodegradable municipal waste in adiabatic reactor under forced aeration were monitored: temperature and mass of the substrate, volatile solids content, C/N ratio and pH-value. Microbial succession was monitored through the estimation of mesophilic and thermophilic bacteria and fungi. The initial rapid increase of temperature within 24 hours in all seasons, involves transition from mesophilic to thermophilic phase caused by significant increase of microbial activity. Thermophilic bacteria were the main contributors to composting and played an important role in organic compounds degradation. The highest value of volatile solids conversion of 56 % was achieved in the winter sample, when the reactor temperature was reached its maximum value of 64 °C at the 2th day of the process. The timing of the thermophilic stage in the composting process affects the microbial succession.

composting ; biodegradable municipal waste ; microbial activity

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