Central waste water treatment plant, Zagreb

Central waste water treatment plant, Zagreb

This plant uses a combined heat and power station that produces more regenerative energy than is actually required for the secure operation of the plant.
Completing the „Central Waste Water Treatment Plant Zagreb“, WTE Group set a milestone in the European environmental policy. The capital of Croatia, home to almost one million inhabitants and thus the focus of this rising nation, did not dispose of but a minor facility for waste water treatment, at the expense of the citizens and at the expense of the environment – in particular the river Sava. After proper international tendering, we, as consortional leaders, were assigned the designing, construction, and a 28 year operation of the facilities within a BOOT-concession.

The scope of performance comprised – beside the central treatment plant for 1.2 million inhabitants, involving an extension design to 1.5 million inhabitants – the alteration and upgrading of the old town sewer, being several miles long, the construction of the new town sewer of double the length, as well as the connection of the sewage plant to the infrastructure by means of road and bridge construction. Additionally, we provided the financing of this 260 million Euro project which constituted in those days Europe’s largest environmental project; institutes involved in the financing were KfW, Frankfort and EBRD, London.

Being concessionaire, we took on the function of a builder and project controller, as well as all commercial and administrative duties during the designing and construction period, including the subsequent operational control. Beside the concessional unit, WTE established an investment entity that was – as general contractor – responsible for the implementation of investments. Technical operations of the facilities are being recognised by an independent operations unit. Timely integration and training of professional staff provided frictionless commissioning.

Only two years after breaking ground, the mechanical stage was commissioned in April 2004. By September 2007, the completion of the plant was spurred on by successive implementation of single biological stages (25–50–75–100 %). The plant was completed while under full operation of the respective stages. Beside the biological technology for water treatment, the plant provides sludge fermentation for the purpose of biogas generation, as well as a combined heat and power station for the generation of electricity in order to minimise energy costs and residual materials. The accomplished large plant will be operated by our WTE team until 2028.
Downloads
Data sheet WWTP Zagreb
PDF-File, 2.8 MB