Attachment 6 - Odour Impact Assessment - Katestone · 132005.638.06

increase during turning of the compost or export of material, but again these emissions can be expected to be low
in offensiveness.

The other potential source of odour from the composting operation will be leachate. Leachate may be generated
from wastes in the uncovered mixing and intermediate storage areas, product in the covered maturation bays and
by the in-vessel compost. Most leachate will be generated from the uncovered green waste stockpiles during and
following high rainfall events. All leachate will be captured and managed to minimise emissions.

Odour emissions from leachate will be managed by minimising the amount of leachate formed and capturing and
re-processing leachate where possible. While the leachate management strategy is under development, it is
currently anticipated that leachate and stormwater runoff will be managed as follows:

    •    Stormwater runoff from the green waste stockpiles will be directed to a high efficiency sediment (HES)
         basin with integrated floating wetland for treatment. Stormwater from the green waste stockpiles is unlikely
         to generate strong or offensive odours due to the relatively fresh nature of the organic matter in the
         stockpiles, thus a HES basin is a suitable treatment option for this runoff. The HES basin will be dosed
         with flocculant to assist with the removal of sediment.

    •    Leachate from the mixing and intermediate storage areas, static piles in the in-vessel composting system,
         and from the maturation bays, will be collected and reused as process water in the in-vessel system.
         Process water will be added to the piles upon formation for optimal moisture content and can continue to
         be added during the pasteurisation phase to maintain optimal levels. Microorganisms that are contained
         with the leachate can speed up the composting process.

    •    The process water will be stored in an enclosed tank ventilated into the tunnels building, so that any odour
         emissions are treated by the biofilter.

    •    Leachate drainage systems will be inspected regularly and cleaned and desilted as needed, with any
         residual material being incorporated into the compost mixing process.

    •    Visual inspections will be conducted to identify any areas of pooled leachate, and any leachate pools will
         be cleaned up via sucker truck or absorbed with green waste to ensure that standing leachate is not
         present for extended durations.

Leachate is not, therefore, expected to represent a significant potential source of odour emissions to air at the
composting facility.




 Katestone Environmental Australia Pty Ltd                                                      17 September 2026
 D25072-8 Noosa Council - Noosa Composting Odour Assessment - Final                                       Page 5