The Flemish government has a clear ambition: by 2035, public bus transport must be completely emission-free. De Lijn is fully committed to this transition with an extensive electrification plan. This includes not only the purchase of 3,430 electric buses, but also the conversion of 138 depots with the necessary charging infrastructure. For this large-scale adaptation, De Lijn is working with Equans, the partner responsible for the electrification and management of the depots.
Tailor-made solutions for fire water containment: Collinet's expertise
The electrification of depots brings new challenges, including the containment of firewater during incidents involving electric buses. Extinguishing an electric bus requires a significant amount of firewater and foam. This water must not simply enter the sewer system, but must be collected and stored in a controlled manner. This is where Collinet's expertise comes in. Collinet thoroughly analyzes the project and designs custom solutions for firewater containment. Collinet's engineering department has developed an automatic valve pit, which was designed and produced in collaboration with De Lijn and Equans. These valve pits ensure that during an emergency, the firewater does not disappear into the sewer, but is diverted to a buffer tank. The valve pits operate on a plug-and-play principle, meaning that as much work as possible is done in the workshop so that installation on site proceeds smoothly and efficiently.
Automatic valve pits linked to the fire alarm control panel
An important aspect of the valve chambers developed by Collinet is their automatic operation. The valves are linked to the depot's fire alarm system. In the event of a fire, they can be activated automatically at the touch of a button, shutting off the discharge into the sewer system and safely storing the extinguishing water in a buffer tank.
Successful implementation in Zomergem
A concrete example of this innovation is the modification of the De Lijn depot in Zomergem. Collinet supplied and installed the following here:
- One double-walled HDPE Weholite buffer tank with a capacity of 138 m³, a diameter of Ø3000/ø3246 mm and a length of 19.6 meters. The tank included a built-in pump system for efficient water drainage.
- Four automatic valve chambers, custom-made according to the existing infrastructure. They were manufactured from double-walled HDPE Weholite pipes and base plates, resistant to chemical influences and groundwater pressure.
The installation of the buffer tank in Zomergem posed a challenge due to high groundwater levels and the proximity of a wadi. Continuous dewatering was performed, and sheet piling was installed to guarantee stability. To prevent the tank from floating, a thick concrete cover slab was poured on top of the tank. In addition to the technical specifications, the buffer tank also fully complies with the new VLAREM II regulations. This legislation, which takes effect on January 1, 2025, requires industrial companies to take preventive measures against leaks and contamination by hazardous liquids. Collinet's buffer tank is designed to safely store firewater and other potentially polluting liquids and features advanced leak detection and security systems. As the only manufacturer in Belgium of double-walled underground storage tanks that complies with these standards, Collinet guarantees maximum environmental protection and compliance with the strictest safety regulations.
Innovation and sustainability go hand in hand
The collaboration between De Lijn, Equans, and Collinet demonstrates how innovative and sustainable solutions are crucial for the electrification of public transport. Thanks to Collinet's customized solutions, not only is safety at the depots guaranteed, but the environmental impact is also limited. In this way, Collinet contributes to an emission-free future for public transport in Flanders.
