First Hobas CSO chamber south of the Alps successfully installed

In October 2017, the municipality of Castel San Pietro in the Swiss Canton of Ticino has been provided with a sustainable, environmentally friendly solution for its sewer system: More than 40 interested people watched a Hobas CSO chamber being installed in the astonishing time of merely one day. The structure reliably separates suspended solids from the wastewater transported in the local combined sewer.


When rain, stormwater runoffs and municipal wastewater flow together in a combined sewer channel, strong precipitations can lead to critical situations: Wastewater treatment plants are overloaded and large amounts of polluted water run into ecologically sensible lakes and rivers. Overflow structures offer a solution for this problem. With the Hobas CSO (Combined Sewer Overflow) chamber, Amiblu provides a particularly reliable and efficient option.


Early in 2017, the first CSO chamber on Swiss soil has been installed in the Canton of Schwyz. A few months later, the second one was realized 200 km further to the south, in San Pietro, Canton of Ticino. Once again, the municipality was looking for a solution to manage overloads of its combined sewer during heavy rainfalls in an efficient and environmentally friendly way. Amiblu produced a CSO chamber of Hobas GRP pipes with 8 m length, which consists of a main pipe DN 800 and an overflow pipe DN 450. Additionally, a GRP valve chamber DN 1200 was supplied to throttle the outlet to the WWTP.


The installation of the chamber on October 19, 2017, attracted many interested visitors: More than 40 persons from the surrounding cities, people involved in the project, and representatives from politics and industry watched the construction works with excitement. And the inhabitants of Castel San Pietro are now happy to count on a reliably functioning sewer overflow system for several decades.

Project ID: [00032312]
City:Castel San Pietro
Application:Sewer, Combined Rainwater-Sewer System
Total Length:8 m
Nominal Diameter DN800 | 450 mm
Nominal Pressure PN1 bar
Nominal Stiffness SN10000 N/m2
Contractor:CPA, Lugano
Client:Municipality of Castel San Pietro

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