As a global leader in the water and waste management sectors, we have been operating for over 160 years all over the world. We provide essential services to protect the resource and improve quality of life wherever we operate.
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To remember
- Nature-based, tailor-made solution that complements traditional wastewater treatment systems
- Improvement of the quality of treated wastewater through better removal of micropollutants
- Regeneration of natural environments through the creation of wetland habitats
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What is a Dragonfly® Zone?
A Dragonfly® Wetland provides complementary treatment to wastewater, relying on natural ecological processes such as phytoremediation.
Inspired by the functioning of natural wetlands and their actions on water (hydraulic regulation, mechanical filtration, biodiversity, sedimentation, etc.), the Dragonfly® Wetland is a vegetated discharge zone made up of a series of compartments (basins) located at the outlet of a wastewater treatment plant, or a rainwater network, and in which water circulates. Each basin is home to local plants and microorganisms selected for their ability to absorb certain pollutants. The diversity of wetlands, with variations in depth and flow velocity, makes it possible to optimise treatment, thus significantly improving the chemical and bacteriological quality of the water. These areas also provide habitat for fauna and flora dependent on the wetlands.
Based on the self-purifying capacity of wetland and aquatic ecosystems, the Dragonfly® Wetland plays an essential role in the fight against micropollutants and their diffusion in receiving environments.
Vegetated Discharge Zone on which SUEZ worked as a delegate in Aix Ouest
Credit: Régie des Eaux du Pays d'Aix
A vegetated discharge zone meeting several challenges
The Dragonfly® Wetland is a unique ecosystem that, in addition to filtering water, is home to exceptional biodiversity, protects us from the effects of climate change and is a valuable educational tool.
Preserving aquatic environments
The Dragonfly® Wetland makes it possible to refine the quality of treated wastewater through a complementary treatment, phytoremediation (or "water purification by plants"), before it is returned to the natural environment. By reducing the impact of wastewater treatment plant discharges, it contributes to the preservation of aquatic environments.
One of the fundamental principles of this approach is to create a "buffer zone", which preserves the quality of the receiving aquatic environments. The results obtained in terms of purification are significant: retention of suspended solids, improvement of physicochemical parameters (temperature, oxygen, etc.), reduction of pathogenic bacteria and reduction of micropollutants.
Promoting biodiversity
Beyond its purifying role, the Dragonfly® Wetland promotes biodiversity by strengthening the local fauna and flora. It is part of the existing green and blue belts and allows the recreation of habitats for aquatic and terrestrial species, thus participating in the renaturation of the sites.
Adapting to the consequences of climate change
Faced with the challenges of climate change, the Dragonfly® Wetland plays a key role in hydraulic regulation. It reduces and smooths water inflows into the receiving environment while creating a buffer zone that protects sensitive aquatic ecosystems.
Dragonfly® Wetland: a solution that adapts to your installation
The Dragonfly® Wetland is an adaptable solution, depending on your context and your local environment. It is custom-designed and can be deployed on sites and facilities of different sizes. The development of the
the Dragonfly® Wetland or Vegetated Discharge Zone takes place in several stages.
Pre-study
This first step consists of studying the available space, the local environment and the receiving environment, then carrying out a precise sizing of the Dragonfly® Zone, taking into account the residence time of the water. A landscape design is designed to harmoniously integrate the Dragonfly® Wetland into its environment, while using plant engineering to maximise purification capacities
Road repairs
During this second stage, the different compartments of the Dragonfly® Wetland are created. This includes the design and layout of the structures needed for water management and planting. An educational trail is also designed to raise public awareness of environmental issues and the importance of water management.
Operation and monitoring
Once installed, the Dragonfly® Wetland is maintained regularly to maintain its proper functioning, while ensuring the development of biodiversity. Monitoring of the system's performance and efficiency is set up. Organised visits allow the knowledge gained to be shared, and scientific studies can be carried out to assess the ecological impact and improve practices.
© Régie des Eaux du Pays d’Aix
They trust us
The Dragonfly® Wetland of the Shanghai Petrochemical Industrial Park (SCIP)
SCIP is China's first specialised chemical park.
In 2017, we won the contract to restore the park's Vegetated Discharge Zone (ZRV), thanks to the lessons learned from our ZHART (ARTificial Wetlands) research project piloted between 2012 and 2016 by our main centre of research and excellence, the CIRSEE. The restoration project covers an area of more than 50 hectares, including 16 ha for Phase I (completed in 2024) and 36 ha for Phase II.
We have adapted our Dragonfly® Wetland solution to the tertiary treatment of industrial wastewater, a first in China. The wetland, populated by halo tolerant coastal plants, plays a role as a natural purifier to treat the saline water generated by the SCIP wastewater treatment plant. This is our largest wetland project.
Frequently asked questions
To purify wastewater, phytoremediation relies on the action of macrophyte plants, and more specifically on the bacteria that proliferate at the level of their roots and rhizomes.
Plant sanitation involves three key elements, which work in symbiosis:
- Microorganisms, especially bacteria, are the main actors in the purification process. They break down and transform organic matter and pollutants.
- Purifying plants (aquatic or semiaquatic) absorb the nutrients resulting from this degradation. Their root system serves as a habitat for microorganisms and, in return, they release oxygen, thus promoting bacterial activity. This is why they are called "oxygenating plants".
- The substrate in which these plants grow also plays a key role in retaining certain pollutants.
The most common purifying plants are bamboo, reeds, cattails and sedges. The choice of species depends on several criteria: their purifying capacity, their resistance to pollution, the structure of their roots and foliage, their interaction with microorganisms in the rhizosphere, as well as their contribution to local biodiversity. It also takes into account rigorously selected species, which can serve as biological indicators and promote hydraulic flows, thus reducing the risk of clogging the substrate.
Plant-based wastewater treatment applies to domestic wastewater, industrial wastewater, and rainwater. The selection of substrates, plants and associated microorganisms is adapted to each type of effluent.
This green, educational and fun space welcomes the public and promotes dialogue between stakeholders, in particular through partnerships with local and environmental associations. It is not only a tool for raising awareness among the public, but also a lever for economic development, by encouraging collaboration with the university ecosystem and territorial innovation.
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