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

                                                                                                       [13]
                  Odour Buffer Assessment
                  StarCo Developments


5     MODEL INPUTS


5.1 Source Details

Staff from PAE made an inspection of the Noosa STP in August 2004 to identify the key sources of
odour. The Noosa 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. Based on the odour sampling, the following odour source parameters
were defined:

                                   Table 5.1: Modelling Source Parameters
                                     Diameter/Surface         Release         Flux Rate         Total OER
       Source             Type
                                          Area                Height          (ou.m/s)          (ou.m³/s)
        Biofilter b         Area              64 m²             1.0 m             1.35              86.4
        Scrubber 1 a       Point               8.8 m            0.5 m              ---               50
        Scrubber 2 a       Point               7.4 m            0.5 m              ---               50
        Bioreactor b c      Area            1 348 m²            1.5 m              10              13 480
Notes: a. The scrubbers vent horizontally and so were modelled as low exit velocity (0.01 m/s) with large
equivalent diameters, maintaining volumetric flow rates. A nominal exhaust temperature of 25°C was used.
        b. The initial vertical spread was assumed to be 0.5 m.
        c. Odour emissions from the aerobic half of the bioreactor are assumed to be approximately 70% of
the anaerobic half (based on data in Frechen 2002).



5.2 Meteorology

No long term on-site weather data are available, but local conditions have been modelled using the
recognised meteorological models (TAPM)1 and CALMET. A wind rose diagram for the study site,
taken from data generated by TAPM and CALMET (see section 4.3 and 4.4 for a description) is




1
    The EPA Guideline on Odour Impact Assessment from Developments (July 2004), section 6.4, states: “The
CSIRO’s air quality model TAPM can be used to generate hourly one-year meteorological data required for the
dispersion models. This is a prognostic meteorological model, which eliminates the need to have site-specific
meteorological observations. The model can predict airflow important to local scale air pollution such as sea
breezes and terrain induced flows. For sites where observed meteorological data is not available and the site is
subject to the sea and land breeze effects, it is preferable to use TAPM model for the generation of
meteorological data.”




1898a report final.doc                                                            PAE Job Number 1898a