The European Forum on the Rhine is a meeting centre with numerous facilities. Restaurants, conference and event venues, exhibitions and offices are spread over more than 5,000 square metres. The multi-purpose building is located directly on the Rhine, not far from the French city of Strasbourg. The Forum is therefore also a meeting place for German and French cultures.
Construction of the forum ended in 2019, and towards the end of the construction phase, the planning office asked PPU Umwelttechnik for a wastewater treatment plant to treat the wastewater produced. The aim was to discharge the treated wastewater directly into the Rhine. To achieve this, the COD produced was to be reduced from 750 mg/l to less than 90 mg/l and the BOD5 from 400 mg/l to less than 20 mg/l.
Connecting the building complex to the nearest municipal sewage treatment plant proved to be difficult due to the location and local conditions. As the forum is located on an island and there is therefore no gradient for the inflow to the municipal sewage treatment plant, the clients opted for decentralised wastewater treatment on site.
PPU Umwelttechnik GmbH is known for its containerised wastewater treatment plants. However, as this type of system did not fit in with the visual appearance of the building, the clients asked for an alternative solution. The PPU team had already had years of good experience with wastewater treatment in underground concrete tanks and therefore favoured this solution.
Another challenge was the fluctuating wastewater loads. The forumhas a large catering operation as well as various events at the weekends. As a result, there are always inflow peaks that must not affect the quality of the treated wastewater.
The best solution for this project was an underground wastewater treatment plant with FBBR technology. The PPU engineers provided the clients with precise plans of how the individual chambers should be constructed. This enabled them to cast the multi-chamber concrete tank on site. In total, the plant consists of 5 chambers in which the treatment equipment is located.
At the beginning, the wastewater runs through a grease separator to separate the oils and fats from the kitchen wastewater. The wastewater then flows into a buffer chamber to equalise the inflow peaks. The second chamber serves as pre-treatment and later sludge storage. The wastewater initially rests there so that solids can settle to the bottom.
After pre-treatment, the wastewater flows into the first cascade of the fixed-bed reactor. This is where the actual biological wastewater treatment takes place. The fixed-bed material becomes increasingly finer-meshed up to the penultimate chamber, which increases the degradation capacity.
The fixed bed process is one of the most robust and efficient biological wastewater treatment processes on the market. Microorganisms colonise the growth material and break down the pollutants in the wastewater. With the addition of air, they metabolise both COD and BOD5. Spent microorganisms detach themselves from the carrier material and sink to the bottom as secondary sludge.
The system pumps this – together with the clear water – into the chamber with the lamella clarifier. This separates the clear water from the sludge using a physical sedimentation process. The clear water can flow directly into the Rhine via an overflow weir, while the sludge flows back into the second chamber.
The underground wastewater treatment plant with FBBR technology can be adapted to many projects. Our engineers analyze your specific requirements, such as wastewater volume, local conditions and treatment objectives, and develop a tailor-made solution.
With FBBR technology, COD values below 90 mg/l and BOD5 values below 20 mg/l can be reliably achieved. This corresponds to common standards for direct discharge into water bodies.
Our solutions include buffer chambers that smooth out inflow peaks and ensure consistent treatment. This is especially important for projects with fluctuating wastewater loads, such as event venues.
The plant is equipped with automated control systems that monitor the parameters of the clear water. If deviations occur, adjustments can be made either automatically or manually to ensure consistent quality.
The duration varies depending on the project scope and specific requirements, but is usually between two and six months from the initial inquiry to commissioning.
