Document Type : Original Article
Authors
1
Department of Biosystem Engineering, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran.
2
Department of Biosystem Engineering, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran
3
Professor of Department of Biosystem Engineering, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran.
4
Assistant Professor of Department of Biosystem Engineering, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran.
Abstract
Nowadays, food waste is disposed of in various ways considering the environmental impacts. The energy consumption for each of these methods can have environmental impacts. In this paper, the amount of pollution caused by the conversion of food waste into animal feed has been investigated. For this purpose, a reverse flow food waste dryer had been specifically constructed. Restaurant food waste was collected. Using a power analyzer, amount of kilowatt-hours consumed by the dryer at various operating levels was measured to estimate the quantities of CO₂, SO₂, and NOₓ emitted during the generation of electricity required to dry the waste using three steam power plants, a gas turbine, and a combined cycle system. The emission rates were calculated at temperatures of 55, 62.5, and 70 °C and durations of 90, 150, and 210 minutes, based on conversion factors. Among the different power plants, the steam power plant exhibited the highest environmental pollution due to its elevated production of SO₂ and CO₂. In contrast, the combined cycle system proved to be the most favorable option, generating the lowest levels of pollution. The least harmful method for converting food waste into animal feed involved producing energy with natural gas in a gas turbine power plant over a 150-minute drying period. Environmental and economic analyses revealed that operating at a temperature of 55 °C for 150 minutes resulted in the lowest environmental and economic impacts. Policymakers can use the results of economic and environmental analyses to gain a more accurate understanding of the environmental impacts of different waste management methods.
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