Energy-Saving Mechanism\nof Wastewater Treatment Process\nAdaptation on Natural Temperature Variation: The Case from Coking\nWastewater

The cyclical variations in environmental temperature\ngenerated\nby natural rhythms constantly impact the wastewater treatment process\nthrough the aeration system. Engineering data show that fluctuations\nin environmental temperature cause the reactor temperature to drop\nat night, resulting in increased dissolved oxygen concentration and\nimproved effluent wastewater quality. However, the impact of natural\ntemperature variation on wastewater treatment systems and the energy-saving\npotential has yet to be fully recognized. Here, we conducted a comprehensive\nstudy, using a full-scale oxic-hydrolytic and denitrification-oxic\n(OHO) coking wastewater treatment process as a case and developed\na dynamic aeration model integrating thermodynamics and kinetics to\nelucidate the energy-saving mechanisms of wastewater treatment systems\nin response to diurnal temperature variations. Our case study results\nindicate that natural diurnal temperature variations can cut the energy\nconsumption of 660,980 kWh annually (up to 30%) for the aeration unit\nin the OHO system. Wastewater treatment facilities located in regions\nwith significant environmental temperature variation stand to benefit\nmore from this energy-saving mechanism. Methods such as flow dynamic\ncontrol, load shifting, and process unit editing can be fitted into\nthe new or retrofitted wastewater treatment engineering.