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Central sewage treatment plant, Altenburg

Facts and Figures
Company PORR GmbH & Co. KGaA
Principal Wasserversorgungs- und Abwasserentsorgungsbetriebs Altenburg (WABA)
Location Altenburg - Germany
Type Structural engineering
Runtime 01.2021 - 12.2022

PORR Civil Engineering has been appointed general contractor for the renovation of Altenburg’s central sewage treatment plant

The PORR civil engineering department in Berlin received the contract for general contracting services from WABA, Altenburg’s water works company in Thuringia. This contract incorporates the refurbishment and expansion of the Altenburg sewage treatment plant. Once renovations are complete, the sewage sludge will be used to produce heat and electricity via a combined heat and power plant, or CHP.

The contract incorporates turnkey completion of the construction, including specialist civil engineering works on the foundations of the new tanks and buildings, earthworks and landscaping, concreting works, finishes and technical and mechanical equipment for the new plant sections, as well as the initial operation of all new systems. PORR’s sister company, pde Integrale Planung GmbH, is responsible for the technical project management involved in planning the work.

The renovation project, which is being carried out while the plant continues to operate, will see the addition of a new primary sedimentation basin, two digestion towers and associated gas treatment and storage equipment. A brand-new machine house is also being constructed. This incorporates the necessary pumping equipment, a new centrifugal sludge dewatering system and three CHPs to generate heat and electricity from the resultant sewer gas. To keep the sewage treatment plant in operation during the construction period,

all wastewater entering the system through the structural connection to the new primary settlement tank is being diverted directly from the sand trap to the aeration tanks via a temporary siphon system.

A valuable source of heat and electricity 

The solid steel plates of the two 2,100m³ digestion towers are to be welded together on the construction site. These towers operate by anaerobically stabilising the sewage sludge at approx. 35-37°C using mesophilic microorganisms and bacteria. The sewage gas generated by this process will be used to power the operation of the sewage treatment plant, making the system almost entirely energy self-sufficient. Once complete, the sewage plant will do far more than just purify wastewater – the new CHPs will make a significant contribution to a sustainable future, generating both green electricity and local and district heating.

Safe and sustainable adherence to a demanding schedule

The PORR team will continue working on the project right through to initial operation, lending their specialist expertise to a trial operation process before handing over a fully functional plant with all new systems operational. The ambitious realisation schedule for this project allows for just 18 months until project completion.