Water Protection Project, Preliminary and Final Design of Sewerage System Expansion and Reconstruction; WWTP Conceptual Design

Client: Međimurske vode, Čakovec
Commissioner: Hrvatske vode, Zagreb
Completion year: 12/2012

Through previous network conceptual design the necessary reconstruction and rehabilitation of sewerage system has been determined as well as the possibility of a potential extension of the sewerage system to the suburbs. Further, according to the obligations undertaken in the EU accession process the wastewater treatment plant is required to be reconstructed in the way to perform the third stage of treatment, but also to provide an adequate solution of the sludge problem.
The Preliminary design of the reconstruction and modernization of the wastewater treatment plant analyzed the existing state of the wastewater treatment plant, which has been in operation since 1998 and defined the necessary measures to ensure the third stage of treatment for the anticipated capacity of 75.000 ES. In addition to improving the treatment process the project has solved the problem of sludge. Applied technology to dehydrate sewerage sludge by gravitation and drying and further removal of organic matter and pathogenic micro-organisms from the stabilized sludge has been used. Sludge treatment enables preconditions for the use of treated sludge in agriculture and as a soil improver for non-agricultural purposes.
With prepared Technical Documentation the building permit has been obtained. The main works on the wwtp include, as follows:

Construction of bio-reactors additional volume for the removal of nutrients.
Installation of equipment for the removal of phosphorus.
Construction of the bioreactor sludge stabilization
Construction of sludge drying beds.

The Preliminary and Final design for the sewerage system reconstruction developed the technical solutions and are in accordance with the relevant regulations to the extent necessary for obtaining local permits at first and the final design approval. The part of the project that refers to the development of technical documentation includes reconstructing 9,5 kilometers of main pipe dimensions DN 300-2000 and reconstruction of two overflows with construction of retention basins in total volume of 1860 m3.