Attachment 6 - Odour Impact Assessment - Katestone · 132005.638.06

the food waste receival hopper, a sealed vessel fitted with a hydraulic lid that will remain closed except during
deliveries. Material will be transferred from the hopper by an enclosed screw conveyor to the shredder, which will
be fed simultaneously with green organics so that blending occurs entirely within the shredding step. There will be
no mixing of food waste in the open.

The mixed material will be promptly transferred to the in-vessel composting system, minimising the time that this
material has the potential to generate odour emissions to air. Air from within the in-vessel system is extracted to
biofilter.

Once pasteurisation has been achieved, the compost will be removed from the in-vessel system and stored in
under cover maturation bays for approximately 6 weeks before being sold as finished compost. This area being
covered will prevent ingress of water, which will minimise the potential for leachate generation and allow better
management of moisture levels in the compost.


2.3          Odours from composting and proposed controls

The delivery and storage of green waste can be expected to represent a minor odour source, except in cases when
that waste is contaminated. In such cases, the odour potential may be high but effective management plans will
ensure that highly odorous materials will be dealt with such that their emissions to air are either minimised or
captured and treated (prioritised either for immediate shredding and composting or for disposal in the landfill).

The Queensland Government’s Model Operating Conditions and Best Practice Environmental Management
Guideline documents for ERA 53(a)—Organic material processing by composting set out odour ratings for different
compost feedstocks, with each feedstock type rated either Low, Medium, High or Very High. Green waste is rated
Low. Shredding of green waste generates odour, but these odours are not normally strong or offensive, and this
activity is already taking place at the site.

The delivery and storage of food waste rated Low or Medium will have greater odour potential, but this waste will
be delivered directly into a sealed hopper, minimising the potential for odour emissions to air. Once fed to the
shredder and mixed with green waste, the mixed material will be promptly transferred to the in-vessel composting
system, minimising the time that this material will generate odour emissions to air. The green waste will also act as
an in-situ biofilter once mixed with the food waste, reducing the potential for significant odour emissions from the
food waste during the short period of time that it spends in the intermediate storage area prior to delivery to the in-
vessel composting system.

The pasteurisation phase of composting has the greatest odour-generating potential and the greatest potential to
generate strong or offensive odours, as organic material is aerobically broken down by microbes. However, with
this process taking place in-vessel with extraction of emissions to biofilter, the actual emissions to atmosphere will
be small in magnitude and inoffensive in nature. Well-maintained biofilters typically achieve at least 90% odour
removal efficiency and the residual odours that are emitted are generally inoffensive, being earthy/woody in
character. Biofilters represent best practice odour control for this activity according to the Queensland
Government’s Best Practice Environmental Management Guideline ERA 53(a)—Organic material processing by
composting.

Odour generation potential of the compost is significantly reduced once pasteurisation has been achieved. The
maturation bays containing finished product can be expected to represent the main source of odour emissions to
air from the proposed composting operations, due to their areal extent and their emissions not being captured and
treated like those from the in-vessel composting system, but their emissions will be low in intensity and
offensiveness, similar to store-bought compost. Odour emissions from finished product stored in maturation bays
will be managed through routine monitoring of key compost parameters and regular turning to ensure continued
stability and prevention of the development of anaerobic conditions. Given the reduced biological activity and
controlled handling at this stage of the process, strong and/or offensive odour emissions during maturation are not
expected. Therefore, the maturation bays represent a minor to moderate odour source. Odour emissions may




 Katestone Environmental Australia Pty Ltd                                                       17 September 2026
 D25072-8 Noosa Council - Noosa Composting Odour Assessment - Final                                        Page 4