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

Report to Pacific Air & Environment Report No. SEPO04176

INTRODUCTION

AirLabs was commissioned by Pacific Air and Environment to sample and analyse duplicate
odour samples from the following sources at the Noosa Wastewater Treatment Plant:

° Biofilter
e Bioreactor
e Activated carbon scrubber (attached to the primary clarifiers)

All sampling and analysis was conducted by AirLabs on the 30" September 2004.

TEST METHODS
Odour

Odour sampling and analysis was conducted in accordance with the Australian/New
Zealand Standard 4323.3 ‘Stationary Source Emissions — Part 3: Determination of Odour
Concentration by Dynamic Olfactometry’.

Sample Collection

Point source samples (carbon scrubber) were collected using the “lung-in-the-box”
technique. The sample was drawn through a Teflon® tube that fed into a Nalophan®
sample bag. Approximately 40 litres of sample was collected. Area samples (Biofilter and
Bioreactor) were collected using an emissions isolation flux hood. All samples were

analysed within 30 hours of sample collection.

Sample Analysis

The odour concentration of each sample was determined using a dynamic olfactometer
operating in the forced choice mode utilising a step factor of 1.5. Two ports were
available to each panel member; one presenting the odorous gas and one presenting a
neutral reference gas. Individual threshold estimates for each panel member were
determined and the corresponding odour concentrations were calculated. The odour
panellists were all familiar with the procedure and specially selected in accordance with
the Australian Standard criteria. The total number of dilutions of the sample at which 50
percent of all responses of the panellists confirmed odour detection is reported as the
panel threshold, and is expressed in odour units (OU).

The precision of results obtained by these techniques lies statistically within the 95%
confidence interval.

Odour Emission Rate

For those samples collected using the flux hood, the odour emission rate (OER) was
calculated by multiplying the odour concentration by a function of the residence time of the
odourous air flow and the flux hood’s vertical footprint.

 

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