Rotterdam is rethinking their city to take the next step towards a circular economy. Collected food waste becomes a source for new products. I interviewed manager Joost van Maaren and project leader Daan van den Elzen to hear how they are introducing separate collection of organic waste and how this is helping them transition to a more resilient city in Rotterdam.

“De Rotterdam” and Erasmus Bridge @ De Kop van Zuid

To what extent is food and organic waste an important item for Rotterdam?

The city of Rotterdam is intensively connected to its port, which is the biggest in Europe. Many fossil fuels are transshipped, traded and processed. The traditional port activities will be challenged by increased need for resilient and livable city, and the increased need for reused and recycled resources. This will pose challenges and new opportunities for Rotterdam.

To a port city like Rotterdam, which is situated in the delta of various rivers, resilience is very important. Due to climate change, potential flooding and rising sea levels are increased risks for Rotterdam. Reducing and recycling food and organic waste is something we can act on now to reduce climate change risks in the future.

What is the biggest challenge towards organic and food waste? 

One of our key challenges is how to address behavioral change and support people to reduce food waste. Right now, each person in Rotterdam wastes about 94 kg of food waste per year. This includes 52 kg of avoidable food waste. The value of mixed organic waste is about 60 times lower than from food. Both the city and its inhabitants will save money when food waste is prevented. About one third of the food we buy to consume is lost. In case of Rotterdam, there is 38,000 tonnes of food waste which could have been prevented.

Behavioral change is also needed to increase source separation of organic waste. Rotterdam produces about 82,000 tonnes organic waste from households per year. About 71,000 tonnes is processed in a waste-to-energy plant and remaining volumes are separately collected and processed to compost, biogas and other applications. The potential for additional separate collection of organic waste is still very large as these 11,000 tonnes are collected at the door from just 25 per cent of our households.

“One of our key challenges is how to address behavioral change and support people to reduce food waste”

Can you give an example of how you are addressing behavioral change?

Rotterdam participates in a project “How to improve waste collection in cities with high density of living building?”. The objective of this project is to find instruments for cities which improve their source separation of waste in high density residential environments.

There are a wide variety of best-practice waste management systems available for areas with houses with a garden. Examples are pay-as-you-throw, high service on resources (frequent collection), reversed waste collection (collection of resources at the door, residual waste at certain locations in the neighborhood). However, for apartment areas there are no best practice systems available. Challenges faced by high-density urban areas are a lack of (storage) space within apartments, shared collection bins with no ownership, and a lack of social cohesion and control.

Participants in this project include eight large cities in the Netherlands, and five national stakeholders. The project was designed in close cooperation with professors, researchers and practical experts in behavioral science. More information about this project is available here.

Rotterdam reintroduced collection of organic waste, what are your reasons?

Much of the debate and attention in Rotterdam is focused on packaging materials. The attention for packaging materials is because of extended producer responsibility and its impact on litter and plastic soup. For households, separating packaging materials means a large reduction in volume of residual waste. Because of this focus, we miss significant opportunities to reduce our climate change impact. Now, part of the debate is shifting towards food waste due to recent local and international publications like the recent launch of the C40 & WBA’s ‘Global Food Waste Management’-guide in Rotterdam.

In 2006, organic waste collection was stopped in Rotterdam. Separate collection of paper had more potential in terms of environmental impact and revenues. Therefore, the organic container was switched for a paper container.

Today, 40% of Rotterdam’s residual waste is organic. There is a clear business case in Rotterdam for separate collection of organic waste. Our costs for processing residual waste via waste-to-energy is relatively high. Processing organic waste via composting is significantly cheaper. As the costs for collection are the same (residual waste is now collected once per fortnight instead of once per week), we save costs. Additionally, it helps to reduce the impact of Rotterdam on climate change and it is a local source of circular resources.

Research by Metabolic, Circle Economy & others shows food waste needs more attention in Rotterdam . Even in areas where organic waste is collected, still 80% of our food waste ends up in residual waste.

What is your strategy for addressing food waste?

We approach the issue step-by-step. As a first step, we re-introduced the separate collection of organic waste in selected neighborhoods. About 25% of all houses in Rotterdam are suitable for door-to-door collection: neighborhoods which have the characteristics of smaller cities where houses have a garden. Now, we have re-introduced collection of organic waste with door-to-door collection system in about 60% of these areas. The first results are an impressive average of 95 kg organic waste per person per year with good quality and it is still increasing. This is 11,000 tonnes of low hanging fruits.” And there is still room for improvement. For example, we now introduce the system in new neighborhoods after the summer so people can start easily. During spring and summer, organic waste has more odor and vermin issues.

Collection of organic waste in Rotterdam

Photo is made by David Rozing, Image provided by Rotterdam

Our second step is to assess the processing of organic waste. Currently, the separated collected organic waste is composted. A logic next step would be anaerobic digestion as this is proven technology to generate energy. However, we are also exploring and researching the next step in creating value from food waste. For example, producing biobased plastics.

Our third step is to experiment to test assumptions. We run a variety of pilots and small and larger scale projects:

• Behavioral aspects
• How to design waste collection in new (highly dense) area development
• Inhouse collections systems
• Separate collection of bread
• Small scale composting per flat
• Door-to-door collection with a “schillenboer”
• Reward schedules

In some of these projects we work together with market parties like Afval Loont, Retourette and BinBang. Pilots might also be a ‘success’ without getting the needed volumes. We learned that small scale initiatives are hard to sustain in the long run. For example home composting is not suitable for the majority of our people, because it requires skills to prevent dehydration and get the right quality.

A next step will be to prepare new policy about waste management. Part of this plan will also be education at schools.

An example of a poster which says: “Your organic waste as a source for new products”

Image provided by Rotterdam

What is Rotterdam’s main message and how do you communicate this? 

At ISWA 2015 in Antwerp, our mayor Aboutaleb presented a view on the future in 10 years: As resources become scarce, waste will pay for itself or even become a profit: Welcome to the goldmine”. This idea, we translated into a communication campaign ‘Van zooi naar mooi’ (From Trash to Flash). Various collection items such as a garbage truck and a collection container are wrapped in gold. This is to express the urban mine: waste is a resource.

Mr. Aboutaleb, Mayor of Rotterdam, in front of a garbage container which transports “gold”

Photo is made by Chris Bonis, Image provided by Rotterdam

What is happening regarding circular initiatives in the city itself?  

Rotterdam has various initiatives working on food waste. Some examples are:

• Fruitleather. Transforming leftover fruits into durable, leather-like material.
• Rotterzwam. Growing mushrooms on coffee grounds and coffee as a service.
• Ioniqa and Unilever: recycling of PET food packaging materials
• Blue City. An old swimming pool where now circular economy startups work. This includes a lab where they test for example new packaging materials from oyster mushroom mycelium.
• Stadsgas. Small-scale biogas installations.
• Dakakkers. Local food production for food donation which creates jobs.
• Kromkommer. Making soup from food that is weirdly shaped.
• Supporting restaurants to grow their own food on temporarily available lands.

National government policy addresses restaurants and retailers. One of the issues which need to be addressed is the reluctance of food donation by the retail sector.

How do you move towards more circularity within your own organization?

From a zero-waste perspective, the waste hierarchy is leading. This hierarchy is based on Dutch parliamentarian Ad Lansink’s preference for waste management options from 1979. On top of this hierarchy is prevention. To prevent you need to rethink, Rotterdam is rethinking the way we work. For example, we now refurbish and reuse playground equipment where we used to use new equipment only. The same we do with our underground collection containers: we used to replace the whole system once being depreciated. Now we only replace parts of the container, such as the body. This saves us on materials and creates local employment.

Another way to increase circularity is via purchasing. Rethinking traditional tender processes pushes the market to take the next step. For example, we used a score for environmental impact as one of the selection criteria in a tender for paper recycling.

Sometimes solutions can also be found in the past: things we used to do but forgot about it. To clean the streets, Rotterdam uses 18,000 street sweepers per year. We asked a research institute, what is the best way to improve the sustainability of a sweeper? The answer was not a different material or a different production technique. The answer is to put the sweepers into ditch water 24 hours before use, which increases their lifetime with a factor of at least 2.

Are you interested in solid waste and the case of Rotterdam? The city of Rotterdam and the NVRD will host the ISWA World Congress on 28-30 September 2020. Save the date for this major opportunity to learn from your pears and get to know Rotterdam.