Appendix 6. Odour Buffer Assessment [As Published] · 132007.2399

4    ODOUR ASSESSMENT

This section explains the approach taken to predict odour levels associated with the
proposed development. The information in this report is based on the data and
methods used for the 2005 assessment of STP odour for the residential
development within a small part of Precinct G associated with the recently approved
development application for resort / residential uses in Precinct F (Holmes, 2005). A
copy of the 2005 report is attached as Appendix A.


4.1 Precinct G Odour Assessment Report
In early 2005, PAE conducted an odour assessment for the Precinct G development
which is approximately 650 m south east of precinct J and also within the 600 m
STP buffer.

This study included dispersion modelling of odour emissions from the STP using
measured emission rates in the CALPUFF dispersion model. The study also included
the results of a small community survey covering existing residential areas to the
northwest of the STP, and some field observations of odour near the STP against
which comparisons were made with the model. The combined weight of these
approaches led to the conclusion that odour impacts in Precinct G would be
acceptable, with the predicted C99.5 1hr odour level below the EPA default guideline
of 2.5 ou.


4.1.1 Dispersion Modelling
Prediction of odour dispersion from the STP was based on the CALPUFF model,
which is a widely recognised USEPA regulatory model. As with any model CALPUFF
requires inputs in three major areas:

        Emission rates and source details,

        Meteorology, and

        Terrain and surface details, as well as specification of specific receptor
         locations.

Staff from PAE made an inspection of the Noosa STP in August 2004 to identify the
key sources of odour. The STP underwent a major upgrade in 1997, enclosing
many of the major odour-producing processes. The inlet works and fermenter are
both totally enclosed and the vapour treated in a biofilter. The primary clarifiers
are also totally enclosed and the vapours treated in activated carbon scrubbers.
The site inspection by PAE identified three dominant sources of odour within the
facility:

        Biofilter;

        Activated Carbon Scrubbers (2); and

        Bioreactor.

Airlabs Pty Ltd was commissioned to conduct odour sampling on these three
sources to determine suitable odour emission rates (OER) for dispersion modelling.
The Airlabs sampling report is included as Appendix B of Holmes (2005).
1898b Report.doc                                                                        6
Noosa Springs Precinct J Development StarCo Developments Limited
PAE Job 1898b