Slide 9 of 24

Though naUTilus is a useful tool for estimating VOC emissions, applying naUTilus can be difficult for many reasons.

• Input files: Creating the naUTilus input file requires detailed knowledge of the input file format and the numbering system used by naUTilus. Creating the input file becomes particularly difficult with large sewer networks. The input file is a text file with various sections specifying branch, node, and drain data.
• Output files: Like the input file, the naUTilus output file is a text file. It lists concentration, temperature, and flow rate data for the sewer elements. For large sewer networks, the lengthy file makes results difficult to view and interpret.
• Naming convention: A problem with both the input and output files is presented by the naming convention used by naUTilus. ISBL input files must always be named ISBL.IN and output files are named ISBL.OUT. Similarly, OSBL files are named OSBL.IN and OSBL.OUT. This becomes a problem with multiple run scenarios. For example, to run naUTilus for the ISBL units feeding an OSBL unit, the user must store each ISBL.OUT file between runs as not to over-write previous results.
• ISBL and OSBL connections: While in reality, ISBL and OSBL units are connected, the connection is not automatically established in naUTilus. For a given facility, naUTilus would need to be run on every ISBL unit with the output of the ISBL files manually extracted for input to the OSBL input file.

These issues are all dealt with by introducing ArcView.