March 18th, 2019

Storage space systems in local drainage systems

Three-tiered storage channel DN 1500 in Isseroda

The responsibility of Kommunalservice Weimar as an independent enterprise of the City of Weimar lies with the public sewage disposal of the Legefeld district and the municipality of Isseroda. On his behalf, Tractebel Hydroprojekt GmbH planned underground reservoir systems on the basis of preliminary investigations for both local networks and accompanied their completion as construction supervisor. 

For Legefeld, a replacement construction of the wastewater pumping station (AWPS) was necessary to increase the capacity of the wastewater transfer to the Weimar-Tiefurt wastewater treatment plant. The existing sewage pressure line was to be retained and thus represented the limiting factor in terms of quantity, so that an underground reservoir was installed upstream of the AWPS to retain the wastewater. The planning also included a sewage elevator and the structural part of the AWPS. The storage channel consists of a 75 m long GRP pipe, DN 2400 and has a retention volume of 185 m³. 

The stone trap shafts DN 3000 are also made of GFK. In Isseroda, a section of the rainwater drainage system was to be closed and expanded in terms of capacity. The official requirement required a throttling of the rainwater discharge into the receiving water into the Utzberger Bach, so that reservoir volume had to be created for the intermediate storage of the rainwater. Due to the limited availability of space, an underground storage space system was also designed here, which was laid in the existing road structure as a multi-stranded continuous basin. The storage channel consists of three 75 m long strands of GRP pipe, DN 1500 and has a retention volume of 375 m³. The DN 2000 throttle chamber with vortex throttle and the DN 3000 emergency overflow chamber are also made of GRP. Furthermore, a DN 700 rainwater canal was renewed to approx. 245 m. 

In summary, it can be said that GRP systems offer optimum freedom for the planning integration into existing structures and limited space conditions as well as for the design of the individual structures. With the appropriate timing of delivery and construction sequence, the GRP material permits high laying speeds and thus short construction times, even for large-format components. 

Holger Michael - Weimar