Nature-based systems deliver more reliable results: constructed wetlands not only achieve very good effluent quality, but also maintain it significantly more consistently than technical small-scale wastewater treatment plants. Studies show a lower probability of exceeding regulatory limits and a higher rate of simultaneous compliance with all limit values – a decisive advantage for safe operation and permitting.
An article recently published presents constructed wetlands in a generally positive light, but contains some shortened or potentially misleading statements.
It is correct that planted soil filters require space. However, it is misleading to imply that they can only treat “limited” volumes of water – every wastewater treatment plant is hydraulically designed for a defined capacity.
Properly designed systems do not produce odors. Fluctuating inflows are a challenge for all biological treatment processes – constructed wetlands are considered robust in this respect.
Constructed wetlands are not a development solution, but a standards-compliant, professional wastewater technology – successfully implemented for over 30 years.
A current research project is investigating the potential of electroactive constructed wetlands as an advancement of conventional planted soil filters.
Based on a one-year pilot system operated under real wastewater conditions, a significantly higher removal performance for organic matter and nutrients was demonstrated.
Through the targeted use of conductive elements, material consumption and land requirements were substantially reduced.
The results show that electroactive constructed wetlands are technically robust and economically viable for practical application.
In Acolman (State of Mexico), a new nature-based wastewater treatment plant is under construction for the Los Héroes Acolman residential development. The system follows the proven model used in our projects in Rayón, Mexicali and Cihuatlán: robust primary treatment, natural sludge humification, and a vertical-flow constructed wetland, followed by a naturally designed polishing pond providing substantial ecological added value.
At Aquatech Mexico 2025, held September 2–4 at Centro Banamex, Mexico City, J&S Engineers will present innovative water reuse solutions. Our Constructed Wetlands (CW) offer eco-friendly wastewater treatment, enabling irrigation for greenery, parks, and buildings while reducing pollutant discharge into rivers. These systems lower freshwater use, energy costs, and wastewater fees, promoting sustainability. Projects like Cihuatlán and Mexicali demonstrate high purification with minimal energy, supporting local ecosystems. Our work enhances quality of life for communities, flora, and fauna, making CWs a cornerstone of sustainable urban water management.
The BW Green Building in Bietigheim-Bissingen redefines sustainable architecture with an innovative Constructed Wetland (CW) by J&S Engineers. The CW naturally treats greywater, and the purified water, combined with harvested rainwater from cisterns, is used to irrigate roof and facade greenery. This approach minimizes wastewater, utilizes excess nutrients for plant fertilization, and cools the building through evaporation, enhancing the urban microclimate. Designed as an attractive green terrace, the CW demonstrates how biological water treatment can be efficiently and visibly integrated into modern architecture.
As a sponsor of the 2025 Pan-American Conference in Paraguay, J&S Engineers promoted knowledge exchange on Constructed Wetlands (CW). Jörg Janisch highlighted their cost-effective, low-maintenance benefits for developing countries. The event featured lectures, workshops, and excursions to advance sustainable water technologies.
We continue our work in the field of nature-based wastewater treatment in Mexico. Our third large-scale project is currently being implemented in Rayón, involving the rehabilitation and expansion of an existing wastewater treatment plant.
Janisch & Schulz Mexico has completed a new constructed wetland near Ciudad Guadalupe Victoria. The project expands an existing lagoon-based treatment plant with two additional purification stages: eight vertical-flow planted filters (12,800 m²) and a series of polishing ponds (14,000 m²). This combination significantly enhances treatment efficiency and supports the ecological restoration of the area.rdert die ökologische Aufwertung des Gebiets.
Janisch & Schulz is participating in the DWA Climate Award with a constructed wetland at the “Little Franklin” nature kindergarten in Mannheim. The system naturally treats wastewater on-site, avoiding discharge into the public sewer. The purified water infiltrates locally, creating wetland habitats that enhance biodiversity and serve as green, cooling areas. This project demonstrates how nature-based wastewater treatment can support climate adaptation in urban environments. The award winners will be announced at the DWA “Water Days” in Berlin in September.
Bw Green Building