Technological Centre

Anacleto Rizzo: “Nature-based Solutions are blue-green infrastructures, designed to provide the same level service than grey infrastructures”

IRIDRA is the first Italian company specialising in Nature-based Solutions for sustainable water management and it continues to be one of the few companys in the world is able to offer this type of solution to their clients. It collaborates in the NICE project, which CETIM leads, optimising green walls for the treatment and reuse of grey water. Today we talk to his partner, Anacleto Rizzo, a specialist in researching, developing and designing artificial wetlands, green infrastructures and drainage systems.

Anacleto Rizzo, partner and researcher at IRIDRA.

How IRIDRA was born?

Everything started 25 years ago, in 1998 when a multidisciplinary group of friends and experts (Fabio Masi, Chemist; Nicola Martinuzzi, Mechanical Engineer; Giulio Conte, Biologist; a few years later accompanied by Riccardo Bresciani, Environmental Engineer) were fascinated by the idea of removing pollutants from wastewater recreating wetland ecosystems, what we learnt a few years later is called Treatment Wetlands, and decided to try to develop a firm specialised in this subject, namely IRIDRA.

Then, all the links with sustainable water management and other solutions such as Sustainable Drainage Systems, Green buildings or Urban forestation came on the way, making IRIDRA, nowadays, one the Italian reference firms in the field of Nature-based Solutions for the water sector, and beyond.

What was the reason for the choice of Nature-based Solutions as the core of your company?

The basic concept is that, often, “Nature does it better”. In terms of wastewater treatment, it was immediately evident that, if the land availability is not an issue, the state-of-the-art designed treatment wetlands were able to provide the same treatment performance as technological solutions, at the same investment costs, but with significantly lower costs for operational and maintenance (almost zero energy, no sludge, no recirculation) and a lower impact on the environment (no odour).

Updated to the XXI century, the interest has even increased, with the increased number of NbS applications that we design and propose, and lies not only in the advantages in terms of cost-effective benefits, but especially in unlocking the true potential of NbS, their capability to recreate nature and be multipurpose.

Nature in real life never does one thing at a time, but always delivers what we call “Ecosystem Services”. For instance, Constructed Wetlands not only treat wastewater, but also provide attractive habitat for biodiversity support. Bioretention systems (rain gardens), not only manage stormwater for hydraulic purposes (infiltration, detention), but can also act as an amenity element in the urban context. Designing and researching effective multipurpose Nature-based Solutions is our goal for the next 25 years.

What is the current state-of-the art for these technologies in the water treatment sector?

In terms of wastewater treatment, the research group has been quite active in the last 25 years and, as IRIDRA, we have always been very engaged in community events and research fields, regularly following the two reference conferences, WETPOL and ICWS, and being often involved in the activities of the IWA specialist group on Wetland Systems for Water Pollution Control.

Based on our experience, we can claim the state-of-the-art of treatment wetlands essentially are two solutions: French Reed Beds, where there is no need for primary treatment, the sludge decomposes aerobically on the top of the beds, removing any need for yearly sludge management, including septic tank emptying; Aerated Wetlands, where an aeration system is placed on the bottom of the beds, significantly reducing the need for land to implement treatment wetlands.

We are also quite proud to claim that we are the only Italian firm, and one of the few in the world, able to propose these NbS to its clients, especially thanks to IRIDRA’s involvement in Global Wetland Technology (, an association including among the most significant firms expert in treatment wetland design.

Do you think, in general, the population is aware of the potential of these technologies? Are they spread in the market?

It depends on which NbS and country policies. For instance, standing in Europe, France and Germany have invested a lot on well-coordinated research on treatment wetlands, that led to detailed design guidelines and regulations, creating the ground for the implementation of thousands of wastewater treatment plants using NbS. Similar considerations can be done for Sustainable Drainage Systems in the UK. Contrarily, the situation in Italy is more jeopardized among the Regions, depending on the willingness of each individual Region in favour or not of NbS.

This if we consider the diffusion in the expert sector, speaking of population, at first sight, I have the idea that much still needs to be done, especially to instill the concept that NbS are green-blue infrastructure, properly designed to provide the same level service (sometimes even better) than well-known grey infrastructure.

On this regard, I think that bottom-up activities with citizens could play a role, a sector in which, as IRIDRA, we have started working in the last years. For instance, we have developed and we are spreading co-design and co-creation approaches in NbS development, such as the StartPark gamified approach ( for co-designing parks as green-blue infrastructure for climate change adaptation, developed in collaboration with the social experts of Codesign Toscana.

We collaborate in the NICE project. What advantages do you find, at a business level, in participating in projects such as NICE?

Since the beginning, IRIDRA strongly believed in Research and Development activities and that the participation to research projects such as NICE would be fundamental to expand future markets. Essentially, the idea is to study front-edge NbS applications, to be among the first in the respective market, with a solid scientific background to properly design innovative NbS in a real environment.

Back in 2002, within the FP5 SWAMP project, we were among the first firms designing and monitoring the performance of treatment wetlands serving scattered touristic facilities, such as hotel or shelters.

For instance, in the ongoing NICE, we are optimising green walls for greywater treatment and reuse, one of the hot topics in the NbS research sector regarding water recycling and circular economy.


«Collaboration with research centres becomes a sort of appendix for testing innovative solutions that, otherwise, would risk remaining only in our thoughts»


What do you think a Technological Centre like CETIM contributes to the project?

The collaboration with research centres like CETIM is fundamental for us. Being always curious about innovation and research, IRIDRA remains a SME without the financial capability to develop research facilities to test the ideas that we collect with our continuous study, involvement in research projects and consultancy services. The collaboration with research centres, therefore, becomes a sort of appendix for testing innovative solutions that, otherwise, would risk remaining only in our thoughts.

What are the current barriers or disadvantages do you find in the application or use of these technologies?

NbS is a broad concept even if we only consider the water sector, and to properly talk about barriers it is necessary to specify which application we are considering. I’ll provide a couple of examples, just to give an idea of the variability of barriers that different NbS applications can face.

If we talk about treatment wetlands for wastewater treatment, the main barrier remains the land occupation; to this aim, for example, the scientific community has intensively studied how to reduce the land footprint, for instance by using forced aeration.

If we consider greywater treatment reuse with NbS implemented on the building, such as green roofs or walls, probably the main barrier is the capability of existing buildings to support the additional weights.

Going towards sustainable drainage systems, perhaps the most subtle one could be the ownership of the NbS (who is the owner of a rain garden on the road? The municipality? The water utility? Who pays for the maintenance?).

What future challenges do you think we will have to face in relation to the use of these technologies?

Of course, they are many but, personally, I think that it is very important to be concrete and reliable when talking about NbS. Many services can be delivered with NbS, but not all, and a narrative of green versus grey infrastructure would not help. Understanding the NbS potential, the possible role in an already infrastructured environment, and the possible win-win synergies with existing or new grey infrastructure is one of the keys to the success of NbS.

How do you view the future of Nature-based Solutions in terms of research and innovation?

Continuing from the previous answer, many things should be researched and there will always be room for disruptive innovations. But a significant contribution towards the NbS implementation will probably come from the so-called applied research.

Properly monitoring the multiple ecosystem services of NbS in the real environment is a big challenge, but collecting reliable quantitative evidence of the multipurpose aspects of NbS will be fundamental for an effective uptake of this approach in the near future.


IRIDRA is an Italian company pioneering the use of Nature-based Solutions for sustainable water management. Since its foundation in 1998, it has focused its activity on analysis, planning and design for the sustainable management of water resources. They are leaders in environmental sustainability and circular economy, two objectives that are very present in their research projects developed at European level.