Aeration‐Basin Heat Loss

Abstract

Recent developments in wastewater aeration systems have focused on aeration efficiency and minimum energy cost. Many other operating characteristics are ignored. The impact of aeration system alternatives on aeration‐basin temperature can be substantial, and design engineers should include potential effects in evaluation of alternatives. To predict aeration‐basin temperature and its influence on system design, previous research has been surveyed and a spreadsheet‐based computer model has been developed. Calculation has been improved significantly in the areas of heat loss from evaporation due to aeration and atmospheric radiation. The model was verified with 17 literature‐data sets, and predicts temperature with a root‐mean‐squared (RMS) error of 1.24° C for these sets. The model can be used to predict aeration basin temperature for plants at different geographical locations with varying meteorological conditions for surface, subsurface, and high‐purity aeration systems. The major heat loss is through evaporation from aeration, accounting for as much as 50%. Heat loss from surface aerators can be twice that of an equivalent subsurface system. Wind speed and ambient humidity are important parameters in determining aeration‐basin temperature.