Slide 7 of 24

naUTilus was developed to as an alternative method for estimating VOC emissions from industrial sewer networks. It is a fundamentals based model, using mass transfer principles to estimate gas-liquid mass transfer and fluid mechanics principles to estimate air exchange between the air in the sewers and ambient air.

naUTilus was programmed in two modules due to differences between the ISBL and OSBL portions of a sewer network. One difference is in assumptions made regarding mass transfer. For an ISBL unit, the user is given the choice of calculating emissions based on either a kinetically or equilibrium limited system. For an OSBL unit, where reaches tend to be longer, it is assumed that the system reaches gas-liquid equilibrium.