As part of the rehabilitation program for Berlin's combined sewer system, the Mauerpark storage sewer was built in the Prenzlauer Berg district of Berlin, the program's largest single project to date. It has a capacity of 7,400 m³ and is intended to help stop further pollution of water bodies such as the Panke and Spree rivers.
During heavy rains, the city's sewers and sewage treatment plants often reach their limits, allowing water from the streets to enter Berlin's waterways unfiltered. This happens about 50 times a year. The purpose of the storage sewer is to absorb the amount of dirty water that the sewage system cannot hold. When the rain stops, the water is returned to the sewer system and pumped to the treatment plant for purification.
In order to minimize the impact on Mauerpark, a popular local recreation area, the 654 m long reservoir sewer was constructed using the pipe jacking method with a tunnel boring machine with earth pressure support.
The excavation began in the 11 m deep starting excavation pit in Bernauer Strasse and ran at a gradient under the paved Schwedterstrasse in Mauerpark to the target excavation pit in Gleimstrasse.
These two excavation pits were also used to connect the new storage sewer to the existing sewer system and an emptying pumping station.
The contract also included the construction of the start and target shafts as sheet pile walls and 19 intermediate shafts as access, ventilation and cleaning shafts.
A particular challenge arose due to the location of the construction site in an inner-city park, which meant that only a tightly dimensioned installation area was available. Considerable restrictions also had to be taken into account in the delivery of the jacking pipes with an outside diameter of 4,500 mm and an individual weight of approx. 32 tons.