Accessibility.Screen_Reader_H1

Construc­tion of a retention tank in Warsaw

MPWiK Warsaw Warsaw, Poland
The retention tank is a significant investment of the City of Warsaw. The main goal of this investment is to improve the wastewater system and prevent street flooding during heavy rains. The retention tank is placed at WWTP “Czajka” in Warsaw, Poland.

This investment is one of the largest of its kind in Europe and it is connected with climate change. CDM Smith has been involved in water supply and wastewater management projects in Warsaw, providing comprehensive design and consulting services for many years. In 2016, we prepared pre-investment analyses and tender documentation of the central control system of sewage network in Warsaw. The next stage of cooperation with the Municipal Water Supply and Sewerage Company in Warsaw (MPWiK Warsaw) and the City of Warsaw was preparing design of the large retention tank and obtaining building permit for the investment. Then, CDM Smith cooperated with MPWiK Warsaw, supervising construction of the tank.

concrete
t
steel
ceiling compression cables

Construction included the following works:

1. Construc­tion of a new sewage retention tank

Wastewater retention tank, with a total active capacity of 81750 m3, consisting of six segments with a capacity of 13625m3, each designed as an independent, two-part, rectangular reinforced concrete chamber, partially recessed in the ground, closed with a reinforced concrete ceiling.

2. Construc­tion or recon­struc­tion of buildings

Newly built facilities are retention tanks with integrated gate and flow meter chambers, e.g. on the pressure pipelines from Żerań and Nowodwory pumping stations, and pipelines.

The existing rebuilt facilities include a sewage pumping station with capacity of Qmax=10.85 m3/s, an inlet channel to the pumping station, pressure pipelines from the Żerań and Nowodwory pumping stations and circulation channels.

While designing the retention tank, CDM Smith developed the following docu­men­ta­tion:

  • Building design (multi-discipline) and a set of documents necessary to obtain a building permit decision
  • Engineering-Geological Docu­men­ta­tion for estab­lish­ing engineering-geological conditions
  • Framework concept for the imple­men­ta­tion of the investment with a directive schedule of works
  • Guidelines for the start-up of the investment together with a schedule
The retention tank will prevent street flooding during heavy rains in Warsaw.
Artur Melchior, Expert of Wastewater Management

Based on the above-mentioned docu­men­ta­tion the decision no. 104/BIA/2016 of 27.04.2016 on the building permit for the retention tank was obtained, which became final.IDS-BUD S.A. with the registered office in Warsaw became the general contractor for the construc­tion of the retention tank. The works started in January 2017 and were completed in February 2020.

CDM Smith Sp. z o.o., as part of its cooperation in the construc­tion of the tank, performed an alternative construc­tion design, detailed working designs and as-built design. CDM Smith was also entrusted with the coor­di­na­tion of design works and author's supervision.

The design docu­men­ta­tion was developed based on the Concept, Functional and Utility Program (PFU) and Construc­tion Project previously developed by CDM Smith. These were multi-discipline executive designs concerning, among others:

  • Retention tank with integrated chambers
  • Gateway chambers and flowmeter chambers
  • Dn1600 pipes from the main pumping station 02.01
  • Inflow pumping station
  • External networks and pipelines
  • Process water networks
  • Rainwater drainage networks
  • Site planning, roads, sidewalks and greenery

The retention tank was success­fully tested in use in June 2020.

The retention tank will improve the wastewater system in Warsaw.
Artur Melchior Designer / Process Engineer

Did you know?


  • The total capacity of the tank is over 20 Olympic pools.

  • The new facility is one of the largest in Europe. Similar tanks are used in Barcelona and Copenhagen.

  • The tank consists of 3 sections and each section consists of 2 segments. Each section is 100 m long and 44 m wide.