Biological filtration is widely used for deodorising in wastewater treatment plants. This technique can efficiently remove soluble odour-causing substances, but minimally affects hydrophobic odorants, such as methanethiol (MT) and dimethyl sulfide. Ethanol absorption capacity for MT (as a representative hydrophobic odorant) was studied, and the MT removal rate formula was deduced based on the principle of physical absorption. Results indicated that the MT removal rate reached 80% when the volume ratio of ethanol/water was 1:5. The phase equilibrium constant was 0.024, and the overall mass transfer coefficient was 2.55 kmol/m 2 ·h in the deodorisation tower that functioned as the physical absorption device. Examination results showed that the formula exhibited adaptability under changing working conditions. These findings provide a reference for engineering design and operation of a process for the removal of MT by ethanol absorption.