Food Waste and Cities: Helping Residents to Source-Separate using Behavioural Science | with Kat Heinrich
Organized on 15th July, 2020
Cities generate huge volumes of food waste. Many cities provide food recycling collections to their residents. Even with these services, many residents continue to dispose of food into residual waste bins. So what can be done about this?
Pilots were recently completed across six cities in the Netherlands to find the answers. This pilot tested ten interventions aimed at helping residents to correctly source separate their food waste. For example, the pilot tested the effectiveness of setting social norms vs rewarding residents for recycling food waste.
Join us to hear from Gijs Langeveld (project manager) and Daan van den Elzen from the City of Rotterdam (a pilot participant) about the pilot. Gijs and Daan share their results, challenges, and lessons for other cities seeking to help their residents source separate food waste.
AUDIENCE QUESTIONS ANSWERED
While the panelists answered several audience questions during the live webinar, they could not respond to all the questions owing to time limitations. We have collated their responses to those questions here. We recommend watching the webinar before checking the responses here:
How replicable do you believe the findings to be, based on your experience? Could it relate in any way to Sub-Saharan Africa reality?
The basics will be true in many situations. People will need the opportunity (infrastructure), the capacity, and the motivation to do so. The underlying behavioural mechanisms have proven to work in different environments, cultures, and sectors. However, the exact intervention(s) and the design of them will always need to be embedded in the local circumstances.
Some studies of household food waste have found @ 20% still in some form of packaging – unopened or partially consumed. Did you find that?
We did analyse the quality of food waste and residual waste by taking samples and analyse what is in the sample. However, we didn’t specifically measure unopened packaging. Even if we did, the sample would be too small to draft conclusions.
What are the major barriers to behaviour change and how do you think we can address those? Any insights
A very interesting question, which needs some more effort to explain. I would suggest reading Chapter 2 of our report. Here an overview is given of relevant literature.
Why has food waste not been collected readily in the Netherlands before this? Is it because of the energy from waste infrastructure/ culture? Therefore, is recycling of all materials pretty low in the Netherlands compared to other EU countries?
Food waste is collected in most parts of the Netherlands, together with organic (garden) waste. It is mandated by law. However, large cities decided in the ‘90s not to implement a collection system, because of contamination and low response. At the time, they got an exemption on the mandate.
The recycling rate of the Netherlands is above 50% and in the top-5 of European Union countries. https://www.eea.europa.eu/about-us/competitions/waste-smart-competition/recycling-rates-in-europe/image_view_fullscreen.
Do you already have food waste collections for businesses? The hospitality sector, factories, and other businesses?
Yes, we have to a certain extent. Collection at businesses is the responsibility of their owners. In the Netherlands, this is by law divided from household waste. Therefore, this was not part of this research.
What were the average quantities of biowaste collected per people or household/year?
In the Netherlands, 86 kg of organic waste is collected separately per citizen per year, while an additional 58 kg is found in the residual waste stream. This includes both food waste and garden waste. Based on the input provided by the Dutch Waste Management Association, it is assumed that 20% of the separated organic waste consists of food waste. If we only consider food waste, this means 17 kg of organic waste is collected separately per citizen per year in the Netherlands, while another 43 kg of organic waste ends up in the residual waste stream.
If only the basic package is introduced and we assume that one in five households separates their waste, the realistic waste separation potential for high-rise buildings in the Netherlands is 16 kg per citizen per year.
More figures are available in section 5.4 of the report.
What’s the RTC sample size used to test each measure? And have you noticed any trends that can be attributed to the household size?
The sample sizes were between 450 and 4100 households. In Chapter 4 the sample size per pilot has been included. Regarding household characteristics, we did find some significant explanatory variables. For example, for Almere, it is notable that single-person households separate their organic waste 10% less frequently than families (p<0.02). Households that contain one or more senior citizens separate their organic waste 27% more frequently than households without a senior member (p<0.01). Other characteristics such as living area and WOZ (property) value do not impact the frequency with which households make use of the organic waste containers. More information household characteristics per pilot are available in Chapter 4.
How frequently was the food waste collected per week?
In Rotterdam once per week. In other cities, this frequency was more or less similar up to a maximum of twice per week.
Did you measure the impact of engagement on the difference in providing free compostable bags vs needing people to buy their own bags when they ran out? (For example: in Wales, they found people used the food bins less when bags were not provided and they now provide free compostable bags)
No, we didn’t measure this (very interesting question though). In most cases, the first set of bags was provided for free. Afterward, people had to buy their own.
What were the methods used to influence attitudes and how was that measured?
Influencing attitudes have been measured via questionnaires. We measured both before the start of the intervention and during/after. The incentive to motivate people varied per intervention. More information about people’s attitudes towards an intervention is available in Chapter 4 of our report.
Were you able to assess changes in food waste generation, that is prevention, based on people being more conscious about food scraps?
No. This would have needed measuring by weight of both food waste and residual waste. At the time of this research, there was no reliable weighting system in containers (per household) available.
You say the third need that was identified was the need for people to be motivated, how do you determine if they were motivated or how did you get people motivated?
Motivation has been measured via questionnaires. We measured both before the start of the intervention and during/after. The incentive to motivate people varied per intervention. More information about people’s attitudes towards an intervention is available in Chapter 4 of our report.
Did some people get all three of those interventions?
In some pilots, we did test combinations of interventions. It is very well possible to combine interventions in a complementary manner. During the pilots, these complementary eﬀects were identified, but no strengthening eﬀects were found: no additional better (or worse) waste separation behaviour was found, compared to what each intervention was able to realise on its own.
Have you had any requests from the broader public for these facilities to be placed in other apartment buildings?
Yes. However, during the pilots, we haven’t expanded to other buildings to keep a well-verified measurement. A number of cities (one of them being Rotterdam) will be implementing food waste collection for their high rise apartment buildings, using the findings of the pilots.