Last updated: September 2024
In 2024, Ozanam (a housing private company) and the French Development Agency (AFD) formalized a partnership to modernize an ecological wastewater treatment plant in Saint-Joseph, a neighborhood in Fort de France. The project focuses on replacing an outdated 30-year-old installation that no longer meets current standards with a plant-based water filtration system based on the ‘Rhizosph’air’ patent. This innovative treatment process utilizes "filter gardens," which combine mechanical systems, a gravity network, and a phytoremediation approach. The system employs filters made of gravel and the roots of local plants, specifically Strelitzia reginae and Cyperus alternifolius, to naturally and effectively filter wastewater without odor (Refs 2, 3, 4). The nature-based system purifies wastewater over an area of 2,000 square meters, with a capacity equivalent to serving 900 residents. This approach offers several advantages, including reduced maintenance costs due to its simplicity, decreased energy consumption compared to traditional treatment methods, and improved water quality released back into the environment (Ref 2). Beyond its technical efficiency, the filter gardens enhance biodiversity (Ref 2) by improving the quality of water discharged into the environment and providing habitats for various species. The solution also integrates seamlessly into the landscape, showcasing vibrant flowers native to the area (Ref 1). Additionally, the project implementers plan to construct a walking path, provide recreational equipment, and install benches to encourage residents to utilize the area as a public green space (Refs 2, 5).
Technical plan of the site
Retrieved from:https://www.ozanam-hlm.fr/nos-actualites/le-personnel-de-lafd-visite-la-step-de-chapelle
Overview
Nature-based solution
- Green areas for water management
- Rain gardens
- Swales and filter strips
Key challenges
- Green space, habitats and biodiversity (SDG 15)
- Green space creation and/or management
- Habitat and biodiversity conservation
- Water management (SDG 6)
- Improvements to water quality
- Cultural heritage and cultural diversity
- Preservation of natural heritage
- Health and well-being (SDG 3)
- Creation of opportunities for recreation
- Social justice, cohesion and equity (SDG 10)
- Social justice and equity
Principal problems in Functional Urban Area (FUA)
- Environmental Degradation
- Biodiversity loss
- Poor water quality
- Health, Well-being and Social cohesion
- Inadequate access to recreational opportunities
Key priorities
Biodiversity (conservation and/or restoration), Social Justice and community
Focus
Creation of new green areas, Creation of any other green urban spaces, Creation of semi-natural blue areas, Implementation of green areas for water management (e.g. rain gardens)
Project objectives
The objectives include:
To replace an outdated system with a new filtration technology that reduces local wastewater treatment costs, improves water quality, and alleviates financial burdens for residents.
To minimize the environmental impact of wastewater by enhancing the treatment process, thereby contributing to the protection of local biodiversity.
To preserve natural heritage through the use of native plants and flowers in the filter gardens.
To enhance community well-being by creating walking paths and installing benches, transforming the area into a public green space that fosters social interaction (Refs 2, 5).
Implementation activities
The French Development Agency (AFD) visited the facility on June 21, 2024, and later, on August 9, 2024, Ozanam and AFD formalized a partnership, securing 25 years of financing for the project (Refs 1, 2, 5). The final phase of the project includes the installation of walking paths and benches, which is still pending (Refs 3, 4).
The wastewater treatment plant at the "Chapelle" residence employs the Rhizosph'air process, which includes a technical room, plant gardens in water basins with two types of plant species (Strelitzia regina and Cyperus alternifolius), a valve system, a filtering screen, and a UV treatment cistern (Refs 3, 5). The filtration process follows five steps:
Wastewater first passes through a screen that prevents solid waste larger than 20mm from circulating.
It is then fed through alternating valve systems that distribute the wastewater to the basins.
The basins undergo cyclical forced airing, where air and water are alternately introduced, creating anoxic conditions for nitrogen treatment through denitrification.
Water passes through a UV treatment cistern, where exposure to sunlight helps purify it.
Finally, the treated water is released back into the environment (Ref 1).
Biodiversity conservation or restoration-focused activities
Biodiversity conservation:
- Protect and enhance urban habitats
- Create new habitats
- Protect species
- Undertake specific measures to protect native species
Main beneficiaries
- Citizens or community groups
Governance
Management set-up
- Co-governance with government and non-government actors
Type of initiating organisation
- National government
- Private sector/corporate actor/company
Participatory approaches/ community involvement
- Co-planning (e.g. stakeholder workshops, focus groups, participatory mapping)
- Consultation (e.g. workshop, surveys, community meetings, town halls)
Details on the roles of the organisations involved in the project
The French Office for Biodiversity (OFB) initiated the project by emphasizing the need to bring the outdated wastewater treatment station into compliance with environmental regulations. In response, the private company Ozanam, began seeking financial and technical partners with support from Technopole Martinique, a business network that assists with technology-driven solutions in the region. Ozanam partnered with COTRAM, the private company responsible for construction, and SAVEA, a subsidiary of Synthea, which developed the patented "Rhizosph’air" prototype used in the project (Refs 1, 2, 3, 7).
The project is co-financed by Ozanam's internal funds and through a financing agreement under a French governmental initiative, which involves the Water Offices of Martinique and Guadeloupe (public sector institutions), the French Development Agency (AFD), and the European Union (Ref 6).
Project implemented in response to ...
... an EU policy or strategy?
Yes
(Ref 7 explains that the project grew out of the need to comply with standards for water quality in the EU Directives. This was brought to the attention of Ozanam by the OFB.)
... a national policy or strategy?
Unknown
... a local policy or strategy?
Unknown
Type of enablers
Technological innovations, Funds, subsidies or investment for GI/NBS in the city (available for the city or provided by the city)
Financing
Total cost
€2,000,000 - €4,000,000
Source(s) of funding
- Public national budget
- Corporate investment
- EU funds
Type of funding
- Earmarked public budget
- Direct funding (grants, subsidies, or self-financed projects by private entities)
Non-financial contribution
No
Impacts and Monitoring
Environmental impacts
- Climate change
- Energy efficiency improvements
- Expected energy efficiency improvements
- Water management and blue areas
- Improved water quality
- Expected improved water quality
- Green space and habitat
- Increased number of species present
- Achieved increased number of species present
- Other
Economic impacts
- Reduce financial cost for urban management
- Achieved reduce financial cost for urban management
Socio-cultural impacts
- Social justice and cohesion
- Improved liveability
- Expected improved liveability
- Improved access to urban green space
- Expected improved access to urban green space
- Health and wellbeing
- Gain in activities for recreation and exercise
- Expected gain in activities for recreation and exercise
Type of reported impacts
Presence of formal monitoring system
Yes
Presence of indicators used in reporting
Yes
Presence of monitoring/ evaluation reports
No evidence in public records
Availability of a web-based monitoring tool
No evidence in public records
Potential risks of implementation and trade-offs
Unknown
References
1.
Ozanam (2024). Le personnel de l'AFD visite la STEP de Chapelle. Ozanam, Accessed on September 3, 2024, [Source link];
2.
Ulysse, E. (2024). Martinique : Une nouvelle station d'épuration écologique à Saint-Joseph, projet innovant pour la gestion durable des eaux usées. outremers360.com, Accessed on September 3, 2024, [Source link];
3.
Ozanam (2023). Inauguration de la nouvelle station d'épuration du quartier Chapelle à Saint-Joseph. Ozanam, Accessed on September 3, 2024, [Source link];
4.
Ozanam (2023). INAUGURATION STATION D’ÉPURATION CHAPELLE Commune de Saint-Joseph. COMMUNIQUE DE PRESSE Ozanam, Accessed on September 3, 2024, [Source link];
5.
Agence Francaise de Dévelopement (n.d.). Construction d’une station d’épuration écologique et innovante. Agence Francaise de Dévelopement, Accessed on September 3, 2024, [Source link];
6.
Ozanam (2023). STATION D’ÉPURATION EXEMPLAIRE POUR LA CARAÏBE. COMMUNIQUE DE PRESSE Ozanam, Accessed on September 3, 2024, [Source link];
7.
Etienne, J. (2023). OZANAM Groupe Action Logement fait procéder au démantèlement de la STEP (STation d'ÉPuration des eaux usées) de la Résidence « Chapelle » et à son remplacement par un Massif Filtrant, innovant, éco-responsable et paysager.. Accessed on September 3, 2024, [Source link];
8.
INSEE (2021). Dossier complet Commune de Saint-Joseph (97224). Accessed on September 3, 2024, [Source link];
Garden filters
https://www.karibinfo.com/news/martinique-lafd-participe-au-financement-dune-station-depuration-ecologique-a-saint-joseph/
Inauguration de la nouvelle station d'épuration du quartier Chapelle à Saint-Joseph
https://www.ozanam-hlm.fr/nos-actualites/inauguration-de-la-nouvelle-station-depuration-du-quartier-chapelle-a-saint-joseph
Inauguration de la nouvelle station d'épuration du quartier Chapelle à Saint-Joseph
https://www.ozanam-hlm.fr/nos-actualites/inauguration-de-la-nouvelle-station-depuration-du-quartier-chapelle-a-saint-joseph
Information about this nature-based solution was collected as part of the Naturescapes project funded by the European Union under Grant Agreement No 101084341.