June 18, 1993


MEMORANDUM

SUBJECT:  Draft Protocol for Modeling a Sewage Sludge Incinerator

FROM:     Dean A. Wilson
          Model Clearinghouse Coordinator (MD-14)

TO:       Rebecca Calby, Regional Meteorologist
          Region V


     In response to your request, the Model Clearinghouse has reviewed your
proposal for resolving modeling issues in the protocol for modeling the
Jackson Pike and Southerly incinerators.  Your main concern with the
protocol was that it proposed to use the Complex I model with off-site
meteorological data to assess impacts from the incinerator in terrain above
stack height.  As an alternative, you propose a procedure that first
determines whether complex terrain concentrations might be higher than
simple terrain estimates and if so, to use the CTSCREEN model to make such
complex terrain estimates.  If the simple terrain concentrations are
constraining, then the Industrial Source Complex (ISC2) model would be used
to refine the estimates.

     The Model Clearinghouse agrees with your proposed scheme.  While there
are some aspects of your proposed scheme that could be questioned as not
providing the most rigorous approach possible, it is a reasonable approach,
given the time constraints you are under.

     Regarding any possible concern on the use of the CTSCREEN model if the
area turns out to be urban, we are not aware of any data that would suggest
that CTSCREEN is not conservative in such a situation.  While the model was
not designed as an urban screening technique, the presumption is that it is
still conservative, lacking any data to the contrary.  While not ideal, the
application of CTSCREEN in this urban area is probably the best path to
follow, lacking on-site meteorological data.    

     If you have any questions, please contact me. 

cc:  D. Bailey
     S. Perry
     J. Touma