ARA Basel: Hydraulic verification and optimization of a distribution structure using CFD simulations

Andrej Sternin, Michel Kuhlmann, 17. May 2024

For the expansion of ARA Basel, TK CONSULT AG, together with HOLINGER AG, carried out the hydraulic verification of a distribution structure, developed optimization possibilities, and dimensioned the installations in the distribution structure using numerical modeling.

Flow pattern in the canal system at an inflow of 1 m³/s.

As part of the expansion of the Basel wastewater treatment plant, a distribution structure is currently being remodeled after the raw water pumping station. The aim of the work carried out was to check the hydraulic design of the planned structure using numerical modeling and to dimension a configuration of installations that meets various functional criteria.

These include, for example, ensuring the most uniform flow distribution in the distribution structure to the three outlet roads under different operating scenarios or ensuring that there is no premature discharge towards the rain and emergency retention basins (MIHABE).

For the planning of the installations in the distribution structure, two geometric concepts were evaluated using numerical CFD multiphase modeling (water/air) methods. The first concept is based on a series of short resistance structures to redirect the water flow (concept «Lokale Einbauten»), while the second concept directs the water through continuous walls to homogenize flow into the central section of the structure, where an additional installation divides the flow (concept «Zentrierung»).

The simulation results showed that the «Zentrierung» variant can achieve a more robust distribution of flow to the three outlet roads under different operating scenarios. In addition, geometry optimizations ensured that there was no premature discharge towards MIHABE.

The numerical modeling provided a deep understanding of flow conditions under different operating scenarios, leading to robust design decisions. Further information can be found on the ProRheno AG website.

Contact person

Michel Kuhlmann

Michel Kuhlmann

MSc. Env. Science ETH

Head of Division Surface Water/CFD

Tel.: +41 (0) 44 288 81 82