Study on Carbon Emission Sources and Influencing Factors in the Treatment of Sauce-flavored Baijiu Brewing Wastewater

The brewing industry, a prominent sector in Guizhou, generates a significant volume of wastewater during the brewing process, characterized by high concentrations of organic pollutants. Consequently, the carbon emissions associated with the treatment of this wastewater are considerable. This paper provides a comprehensive review of the sources, characteristics, and treatment processes of Maoxiang liquor brewing wastewater. It also explores the origins of greenhouse gases emitted during the treatment of such wastewater. Utilizing life cycle assessment, a carbon emission accounting methodology is developed. Further analysis reveals that the water quality, quantity, and treatment processes of brewing wastewater significantly influence the emission factors of CH4 and N2O. This finding suggests that the existing carbon emission factors for sewage treatment processes are not suitable for calculating the direct carbon emissions of liquor brewing wastewater treatment. Therefore, key aspects of carbon accounting in the subsequent stage are identified. Firstly, spatio-temporal monitoring of carbon emissions from brewing wastewater treatment plants should be conducted to establish rational carbon emission factors. Secondly, activity intensity data should be adjusted by subtracting the amounts of COD and TN carried by sludge and the amount of COD removed during advanced treatment stages. Additionally, carbon reduction can be achieved through process optimization and enhanced CH4 recycling.