The problem with food waste
You might think that food waste in a landfill simply breaks down naturally – but this is not the case. In a landfill, the food waste is buried by other rubbish and crushed, which limits its exposure to sunlight, oxygen, and helpful microorganisms.
As it breaks down anaerobically (without oxygen), it releases more methane than it would if it decomposed naturally, like in a compost bin. Methane is a powerful greenhouse gas and has roughly 30 times the impact of carbon dioxide on climate change.
Through the Wellington Regional Waste Management and Minimisation Plan (WMMP) 2017-2023, we’ve set a goal to reduce the amount of waste going to the Southern Landfill by a third by 2026. Our WMMP Action Plan identifies food / green waste collection as having the largest potential for diversion of waste from landfill.
About the Para Kai trial
The trial ran from September 2020 to March 2022 on the Miramar Peninsula. 500 households trialled a weekly kerbside food waste collection service, while another 450 households were composting their food waste in either a compost bin, worm farm, or bokashi system.
The trial has now finished, but the food waste collection service is continuing in the short term while other options are considered. Unfortunately, no new participants are being accepted into the trial.
The Miramar Peninsula was chosen for the trial because it has a diverse range of established communities which are representative of Wellington’s demographics, socioeconomics, and topography in a relatively small, easy to define area.
Predator Free Wellington have almost entirely eradicated rats, mustelids, and possums from the area. Since rodents can be a problem associated with compost bins, any increase in pest numbers in the trial area could be closely monitored.
What we learned
Information was gathered over a 12-month period through a rubbish audit of participating households before the trial began, and again during the trial to provide a comparison.
We also conducted two surveys to understand participant’s perceptions of the success of the trial and a willingness to pay for a food waste collection service in the future. The second of these was finalised in March 2022.
- Approximately 33,000 kg of food scraps collected and diverted from landfill.
- Average reduction in food waste going to landfill of 38.8% per household.
- Approximately 13,000kg of food scraps diverted from landfill.
- Average reduction in food waste going to landfill of 16.4% per household.
- The trial and survey indicate that organic kerbside collection is the most effective method for diverting food waste from landfill. The home composting systems were also popular among most participants and reduced the amount of food waste going to landfill.
- The survey indicated that participants thought the trial was a good idea. Respondents agreed that waste related issues are important and environmental purpose and goals were the key motivation to take part.
- At least four in five respondents across both trial groups indicated they would continue to use the system if the trial continued.
- Key concerns about all the bin types were around smell, attracting rodents, animals, bugs, the volume of food to process, and what to do if something goes wrong. Some in the home composting trial felt they may have selected the wrong type of bin for their household.
More about what we learned
Para Kai – lessons learned from the survey responses (262KB PDF)
Infrastructure Committee paper – Para Kai including Audit Results (9.65MB PDF)
Para Kai Trial - Phase One Survey - Topline Report (Final) (1.06MB PDF)
Para Kai Trial - Phase Two Survey - Report (Final) April 2022 (1.10MB PDF)
The trial findings will inform our next steps in tackling food waste disposal issues and will help us model potential future food waste kerbside collection services.
We are currently rethinking our rubbish and recycling collections and are undertaking a review of our kerbside services, which will include options for managing green waste and food waste. One of the objectives of this review is to minimise the amount of waste going to landfill.
We’ll be engaging with the community to explore service preferences and willingness to pay. Early 2024, we’ll propose a shortlist of options for public consultation as part of the Long-Term Plan process.
If you have a question about the Para Kai trial please email us at firstname.lastname@example.org