Hobas and Flowtite pipes upgrade Poland’s largest WWTP

Better together! For the extension of the wastewater treatment plant (WWTP) Czajka in Warsaw, Hobas PU Line pipes De 3000 and Flowtite pressure pipes up to DN 2800 were installed both via jacking and in open trench. They build the process pipe system of a huge storage reservoir.


As in many capital cities, Warsaw’s population is constantly growing – a fact that requires several adaptations with regard to infrastructure above and below ground. One such measure is the extension of the sewage treatment plant Czajka, which already is the largest and most modern WWTP in Poland. The upgrade involved the construction of a giant 78,000 m³ reinforced concrete reservoir for combined sewage and the connected process system. The client chose Amiblu to produce and supply the complex pipe system for the reservoir. The newly built system should allow for a proper distribution and retention of wastewater flowing from the combined sewer system of Warsaw’s various districts surrounding the WWTP.


Due to sulfuric acids and sedimentation proces-ses, pipes and storage systems for sewage treatment plants need to come with a particularly high corrosion resistance and lowest possible maintenance to ensure a problem-free long-term operation of the plant. With Hobas PU Line, Amiblu offers a product that is tailor-made for such conditions: The pipes’ inner protection layer of polyurethane features an increased chemical resistance and extended lifetime even in aggressive environments. The pipes show a very high resistance to sand abrasion, which is very common in combined sewage systems. The smooth inner surface ensures that deposits collected during periods with less or no flow do not pile up – a very important fact, given the intended periodical use of the reservoir.


It was therefore decided to use Hobas PU Line pipes De 3000 for the main transmission pipeline between the storage reservoir and the main process system of the WWTP and install them via microtunneling. Despite their relatively small wall thickness of 94 mm, the pipes can handle enormous jacking forces of more than 13,500 kN.

Project ID: [00041995]
Installation:Microtunneling, Open Trench
Technology:Flowtite, Hobas
Total Length:400 m
Nominal Diameter DN3000 | 1720 | 600 | 2800 mm
Nominal Pressure PN6 | 10 bar
Nominal Stiffness SN32000 | 10000 N/m2
Consultant:CDM Smith
Contractor:IDS-BUD S.A.
Client:MPWIK W-wa

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