Work on the ZSSO Phase II has started at the end of 1996. The main objective in this stage is creation of ZAGREB SEWER SYSTEM MASTER PLAN, based on the up-to-date technological principles, determine development parameters for this highly important and expensive infrastructural system. Phase II was continued after accomplishment of the Phase I of the same project.
The Zagreb sewerage system optimization
The second phase of the Project includes the following activities:
1. Creation of mathematical hydrology-hydraulic model of the entire sewer system (building stage 1996.)
2. Monitoring campaign continuation
3. Proposal for the Urgent Remedial Measures
- For every flood area a rational and immediate improvement of working conditions were proposed
- In accordance to the Sewer Department plans, priorities will be determined
4. Sewer system Master Plan
- Proposal for feasible reconstruction and improvements of the sewer system, based on the verified mathematical model
- Analyses of Zagreb’s existing sewer system interception possibilities from the adjacent Western and Southern areas
- Recommends Real Time Control of Zagreb sewerage system
- Definition of sewer system elements important for the preparation and maintenance of the future WWTP in Zagreb
- Recommendations how to design and operate the sewer system with a goal to standardise methodological approaches and elements for hydrology-hydraulic analyses
5. Study on the economical profitability of various alternatives and suggested development solution
6. Staff training of the local sewer company ("Vodoopskrba i Odvodnja", Zagreb)
Sewerage master plan has defined short term (urgent remedial measures) and long term development plan for the sewerage system of Zagreb. In sequel main measures are presented as function of different city zones.
Typical measures foreseen in the Master Plan comprehend following activities:
a. Reconstruction or change of existing trunks and sewers at problematic locations and sections (e.g. relining etc.)
b. Reconstruction of certain structures within the system in order to achieve release and redirection of waste water volume
c. Building of new trunks and sewers to overcome local flooding and bottleneck problems
d. Building of combined sewer overflows (CSO) to release storm water into recipient
e. Building of internal weirs and dividing structures within the system
f. Pumping stations will be built at specific locations to control inflow
