A custom valve solution, including a DN400 knife gate valve from AVK France, ensures environmental protection for a new urban development project
As part of the development of the ZAC Plaisance, an urban expansion zone in Rennes, France, a new stormwater control system was implemented to align with French environmental regulations and ensure long-term safety in case of accidental pollution.
The project, led by Rennes Métropole, involved a close collaboration with Sade, responsible for installing the equipment, and AVK France, who delivered a custom technical solution tailored to the site's unique requirements.
Meeting legal and environmental obligations
The ZAC Plaisance development, located along the Ille-et-Rance canal, features a dual DN400 stormwater discharge network that directly feeds into the canal. Although the existing network was in good condition and retained during the redevelopment, the expansion triggered legal obligations under France’s Water Law (loi sur l’eau). Specifically, Rennes Métropole was required to implement a pollution control mechanism to prevent accidental discharges into the natural environment.
The need was clear: provide a reliable isolation point at the outfall of the ZAC to enable swift intervention in case of contamination on site.
A challenging installation environment
The technical complexity of the project stemmed from the limited space and shallow depth at the outfall location. The installation area offered minimal headroom and required a highly compact solution. AVK France quickly responded with a tailored approach, proposing a knife gate valve (DN400) installed in a horizontal position — an ideal choice to meet both the spatial constraints and operational requirements. To allow easy handling in this restricted environment, the valve was equipped with a cover to be backfilled, bevel gearbox, and an offset.
The complete installation included a valve chamber, the knife gate valve, a check valve, and a siphon partition wall, fulfilling both the design and regulatory requirements.
A proactive solution, ready if needed
Although the system has not yet been used in response to a pollution event, its presence ensures Rennes Métropole’s compliance with environmental legislation and provides peace of mind for future operations. The AVK France solution protects the nearby canal and supports the city’s sustainable urban development goals.
“The AVK France team quickly provided a compact and functional solution that matched the exact needs of the site. The adaptability of the equipment was key to making this installation a success.” - Julie ARTOLA, Project Manager, Rennes Métropole.
