Mixed organics (both garden and food waste) is collected as normal through the kerbside service. Trucks deposit the organics inside the enclosed processing hall at the existing plant. The amount to be processed would be set at a level that maximises maturing time in the indoor tunnels and minimises the temporary use of outdoor storage (more work is needed to identify the optimum level). Indoor storage at the site is limited so surplus mixed kerbside organics is sent to Kate Valley Landfill or to alternative processors.

In the long-term (2025) it may be possible to send the surplus organics to a local processor, if one became established.

The diagram below shows how it would work.

* If the organics are being sent to another processor, the transfer station will be either inside the enclosed processing hall at the existing plant or at an alternative enclosed facility. If the organics are being sent to Kate Valley Landfill the material will go to the Council's three transfer stations to be mixed with rubbish.

Risk of offensive and objectionable odour from the plant impacting on the local community

What we do now: Medium to high risk

This option: Medium to low risk (depending on the temporary use of outdoor storage).

Implementation time

Unknown: The Kate Valley Landfill may be able to take about 18,000 tonnes of mixed kerbside organics without needing a change to its resource consent. Any amount over that would need a consent change. We don’t know how long that would take but estimate July 2024 at the earliest.

Estimated cost (over five years)

What we do now: $112 million

This option: $149 million ($37 million more than the existing five-year cost).

Estimated effect on rates (over five years)

What we do now (expected rates portion for 2023/24 per property): $116. This is a fixed cost that everyone pays, which covers the cost of collecting and processing organics. This is a proportion of the total amount you pay for your kerbside recycling and organics service.

This option: 1% increase – this is the annual rates impact over five years.

Dollar amount: $790 over five years. Cost per year is $158. (The exact amount would be finalised through the 2024–34 Long Term Plan process).

Estimated greenhouse gas emissions (generated over five years)

Greenhouse gas emissions are measured in carbon dioxide equivalent (CO2-e). This measure combines the effects of different emissions, such as methane and carbon dioxide.

What we do now: 48,232 tonnes of CO2-e

This option:

If surplus organics are sent to Kate Valley Landfill: 92,181 tonnes of CO2-e, an increase of 43,949 tonnes of CO2-e

If surplus organics are sent to a single North Island processor: 52,010 tonnes CO2-e, an increase of 3778 tonnes CO2-e

Read more about how we calculated our greenhouse gas emissions on the main project page.

Alignment with sustainability policies

Along with central government, we have policies and strategies for managing organics.

What we do now: Aligns

This option: May not align (significantly increases emissions if some material goes to landfill).

Read these policies and strategies on the main project page.