How Sardinia uses economics to underpin its collection success

During the 11-12 March, I was invited to join a study tour to Sardinia organised as part of the Interreg Euro-MED CirBiowaste project funded by Interreg Europe, where our ZWE members ZERO (Portugal) and ECOREC (Greece) core partners. We were fortunate enough to get to spend 2 days touring the capital Cagliari and neighbouring municipalities, understanding how local systems have been so effective.

For me, it was particularly important to go because the Italian island of Sardinia, a semi-autonomous region, delivers one of Europe’s best waste collection and recycling systems – in terms of both performance but also importantly in cost-effectiveness.

A typical study tour exploring the local door-to-door collection – with some questioning looks from the locals.

There are over 300 municipalities in Sardinia, and collectively the island region separately collects 76% of municipal waste generated – with a goal of reaching 80% by 2030. The region also has total waste reduction goals – 10% less from 2022 to 2029, with a big chunk (30%) coming from food waste reduction. 

The actual recycling rate in 2025 was 61.2%, showing a loss of 15% from collection due to contamination, which the region has identified as a key priority moving forwards. Most of this contamination is found in the plastics that are separately collected, as the region has an extremely impressive contamination rate for organic waste collected of just 3.65% (ranging from 13.8% in one of its 14 organic waste treatment plants to just 1.13% in another).

On the island, there are 176 municipalities separately collecting above 80% of municipal waste, representing over 35% of inhabitants. Every municipality except one on the island operates door-to-door collection of waste, with organics and residuals treated on the island and dry recyclables (paper, metals, glass etc) exported to the mainland.

Most people will know and recognise Sardinia for its beautiful beaches, delicious food and mountainous terrain. It’s a hotspot for tourism which makes waste management during these seasonal fluctuations in population especially difficult. In one coastal municipality we visited, Villasimius, the resident population of 2,500 in winter expands to around 10,000 beds during the summer season. Across the island in 2025, 45k tonnes of municipal waste was generated in February compared to a peak of 75k tonnes in August – almost twice as much waste to manage during peak tourist season.

One of the central mechanisms behind Sardinia’s success is the regional penalty & reward scheme that has been in place since 2004. The system basically sets parameters and targets for municipalities to achieve for separate collection. If these results are achieved, municipalities get a discount on the waste tax they have to pay, which is based on the volume of residual waste each municipality generates. If the targets are not met, municipalities must pay an extra charge, which provides the funding for the region to offer discounts to others and balance the budget still.

2024 overview of the penalty & reward system

Currently, only 4 municipalities on the island have Pay-As-You-Throw (PAYT) implemented, and no municipality achieves above 90% separate collection (the best is at 89%). The region has requirements in place for what the PAYT system must look like to qualify for this scheme, which includes 100% coverage of the population and a variable fee only on residual waste generation.

This kind of system must always evolve and adapt to local realities to keep driving progress. As the years have gone on, and performance across the island has improved, the targets have gradually increased as a means to continue incentivising progress and financial reward for high-performing municipalities.

For densely populated areas, often with old and very small streets, this is what good waste management can look like:

In Sardinia, the gate fee for disposing residual waste to incineration sits at around 200 EUR / ton. This is double the price for bio-waste treatment, around 100 EUR/ton, and MBT treatment, which is around 120 EUR/ton. These prices are much higher than the average for Italy, or indeed the European average, especially across the Mediterranean. This reflects the unique challenges posed by island life and the added costs of dealing with waste on its shores. Whilst above the normal costs for many municipalities in Europe, the fact that the fees for residual waste disposal are twice as high as bio-waste treatment is a critical factor in Sardinia’s success. It incentives municipalities to implement door-to-door collection models which minimise residual waste generation.

The Sardinian capital, Cagliari, is a great example of how to deliver high-performing collection systems in densely populated, historic areas. 150k people live in the city, with a density of 1,800 inhabitants per km2. Despite this, it achieves a 75% separate collection rate. Cagliari introduced a door-to-door collection model of 5 key waste streams in 2017, and has been optimising the system ever since. The table below showcases the impressive results achieved in these 9 years.

The municipality estimates that the waste-to-energy incinerator that they send residual waste to has reduced the amount of C02eq it emits annually by over 55 tonnes now compared to 2017 thanks to this waste reduction.

Underpinning Cagliari’s success is their Pay-As-You-Throw system. Using Radio Frequency Identification (RFID) tags on the bins and collection trucks, each household’s fee is determined by the size of their apartment firstly. In the minimum annual waste fee, every household is entitled to 26 put-outs of their residual waste bin – once every 2 weeks. In large multi-apartment buildings, 200L containers are used for organics and dry recyclables, whilst each individual apartment is given a smaller (30-40L) residual waste bin with a unique RFID tag. 

Households pay 1.90 EUR extra for each extra time they put out their residual waste for collection, which is maximum once a week in Cagliari. So each year, a household would only pay a maximum of just under 52 EUR if they generate more waste. This proves that the economic incentive for a successful PAYT system does not have to be huge. It just has to exist to encourage greater awareness and better sorting behaviour from the community.

Visiting Sardinia is an opportunity for municipalities and regional authorities to reflect upon the choices that we have in terms of waste collection and management. If, one the one hand, it provides interesting data about how these models were built up, on the other hand, the onsite visits shall provide the vision of how other municipalities might want to see themselves in a couple of years. Technicalities, fees and real costs are very dependent on each country specifics, but the overall results should inspire us to find the most efficient ways to reach it. 

Isamel Casotti Rienda, Project Manager at ZERO Portugal