Turkey, Wastewater Treatment Plant Ankara, BOT

The Ankara Water and Sewerage Administration (ASKİ) decided to promote private sector participation and to search for a qualified private contractor to finance and to erect the extension of the existing WWTP to full capacity (year 2025) and to operate the plant for a period of 15 years under a BOT (Built–Operate–Transfer) contract.

At the begining of the project, the existing plant was built for an average capacity of 765,000 m³/d  (8.9 m³/s) and should be increased to full average capacity of 1,380,000 m³/d (15,9 m³/s) in 2025.

For the present WWTP and extension to full capacity the activated sludge  plant technique with anaerobic  stabilisation and mechanical sludge dewatering was selected. The full biological plant consist of screens, aerated grit chambers, primary sedimentation tanks, activated sludge tanks, secondary sedimentation tanks, raw– and digested sludge thickeners, digestion tanks, sludge dewatering station, gas holder and block-type thermal power station. The concept of the plant allows for extension of advanced technology for nitrogen and phosphorus removal.

Private sector participation for the extension of the existing wastewater Treatment Plant to full capacity (year 2025) and operation of the plant for a period of 15 years under a BOT contract.

ClientASKI, Turkey
LocationAnkara, Turkey
Services Period1991 – 2001
Project Costmillion EUR
Technical Data
  • Population
6.3 million PE (2025)
  • Av. dry weather flow
1.4 million m³/d
  • Peak dry weather flow
18.3 m³/s
  • Peak storm water flow
31.9 m³/s
  • Total BOD5-load
377 t/d
  • Dewatered sludge
1,130 m³/d
  • Advisory Services / BOT
  • Feasibility study
  • Preliminary design and tender documents, bid evaluation
  • Supervision of works, revision of plans for the execution of works and plant commissioning
  • Process-upgrading for N- and P-removal
  • Definition of technical, financial and legal contract structure for BOT
  • Elaboration of detailed tender documents on BOT basis
  • Bid evaluation and execution of services


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