Energy balance and biodegradability assessments for food waste composting under various c:n ratios and air flow rates

Gökbel, Fuat
During composting process, there are various factors(C:N ratio, air flow rate, temprature, moisture, etc.) which affect the active phase of composting process and thus the biodegradability of organic wastes. The objective of this study was to examine the effect of different C:N ratios and air flow rates on in-vessel food waste composting. The temperature profile, moisture, organic matter loss, C:N ratio and biodegradability were measured. Energy balance was examined around the reactor, the heat loss and daily microbial heat generation were quantified. The maximum average temperature and the highest heat energy generation were obtained under the conditions of 20:1 C:N ratio and 3 L/min aeration rate, 46.7°C and 2.6 MJ respectively. The daily maximum biodegradation rate constant 0.088 d-1 and the highest energy generation per kg volatile solid (VS) 20.0 MJ/kg VS were reached under the conditions of 30:1 C:N ratio and 3 L/min aeration rate. All the experimental results and calculated variables showed that the optimum level of C:N ratio and airflow rate during food waste composting with forced aeration were 20:1 and 3 L/min, respectively.


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High Hydrostatic Pressure (HHP) application, alone or in combination with refrigeration, ambient or moderate heating temperatures; inactivates pathogenic and spoilage microorganisms and conserves the product „„freshness‟‟ with fewer changes when compared to conventional food preservation processes. During handling and frozen storage, quality deterioration of seafood brings the risk of contamination, quality loss and a potential threat to food safety and human health. In this respect, the aim of this study w...
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Pectin-wax-based emulsion systems could be used to form edible films and coatings with desired water permeability characteristics. Pectin is often used in food industry due to its gelling and viscosity increasing properties. Physical properties of pectin are highly dependent on its esterification degree. Waxes are commonly used as edible coatings to enhance the water barrier properties of food products. This study focuses on preparing emulsions with sunflower oil wax (SFW) and high methoxyl pectin (HMP) at ...
Şahin, Serpil; Bayindirli, L. (Informa UK Limited, 1999-01-01)
The effective thermal conductivities of potato were measured at various stages of the frying process. Samples were taken at 30 s intervals during frying, and two different methods (line heat source and modified Fitch method) were used to measure the effective thermal conductivity. An iterative Kopelman model was used for the prediction of thermal properties. The effective thermal conductivity decreased as frying time increased. The variation of experimental measurements by both methods and modeling were wit...
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Şahin, Serpil; Bayindirli, L (Elsevier BV, 1999-01-01)
The convective heat transfer coefficient during deep-fat-frying of potatoes was determined at different temperatures. The temperature, 0.1 cm below the top and bottom surfaces of a 0.05 x 0.05 x 0.005 m potato sample was monitored over rime. The thermal conductivity and specific heat of the sample were expressed as a function of rime, and the data were analyzed using the heat transfer equation with an explicit finite difference method. Crust formation occurred primarily at the bottom surface of the potato s...
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Terahertz time-domain spectroscopy has been used to measure the absorption of water vapor in 0.2-2.4 THz range from low to high humidity at room temperature. The observed absorption lines are due to the water molecular rotations in the ground vibrational state. We find that the absorption strength of para transitions increases as humidity increases, while the absorption strength of ortho transitions increases and then decreases in intensity with increasing humidity. We explain this difference based on the n...
Citation Formats
F. Gökbel, “Energy balance and biodegradability assessments for food waste composting under various c:n ratios and air flow rates,” M.S. - Master of Science, Middle East Technical University, 2015.