Distribution network

Alongside the construction of the water treatment plant, we have begun to construct the waterworks according to the plan, so that during the eighties of the last century we have constructed over 30 km of the main and transfer waterworks. In the previous period, before this planned construction of waterworks, 110 km have been constructed according to obsolete concepts, so that the total length of waterworks is estimated to be 140 km.

In order to determine the exact hydraulic conditions of the distribution network the preparation of multifunctional mathematical model is in progress.

Most of the waterworks diameters is inadequate according to the fire protection requirements, materials applied are inappropriate and the biggest problem is the worn-out zinc pipes. Working pressures are below 5 bars and their physical condition is completely unsatisfactory, so that most part of this worn-out waterworks has to be replaced, since the major portion of water losses in transport is ascribed to the old waterworks.

The particular part of distribution network is the junctions and hydrants. Considering the fact that the old, inadequate waterworks are connected to the new one, there is a large number of junctions of shafts in the system, which are inadequately equipped. Within the junctions there have been placed about 600 caps, 81 fire hydrants and 5 locations for the rinsing of the waterworks. The physical condition of the junctions is unsatisfactory, and recorded water losses mostly occur at the above-mentioned junctions.

Since rather large water losses have been recorded in the system, over 40%, it is necessary to eliminate or at least reduce these losses, which inevitably occur in the waterworks system as “objective losses” and as water losses that occur as a consequence of inadequate and worn-out network (subjective losses).

In “objective losses”, according to the terminology of waterpower engineering we include:

In “subjective losses” we include:

• losses of water at the worn-out pipelines and junctions, hydrants
• losses at water gauges
• unreliable recording of the consumption and similar,
• losses during breakdowns and repairs due to late detection of the failure sites, cracks in the pipelines.

The world experiences of western countries tolerate water losses in transport of 15-20%. According to Serbia waterpower engineering basics, water losses in transport of 18% is calculated in the norm of consumption until the year 2021, which once again shows that the water losses of the present amounts cannot be tolerated anymore.

The reduction of losses is a long-term activity with the precisely set goals and means for their realization. Considering the reasons for the occurrence of “losses” in our town, it is necessary to replace large portion of the old waterworks (30 km in the first stage), execute the revision of junctions (about 290 shafts) and construct mud drums and the necessary number of hydrants. It has to be noted here that a very substantial and long-term works of high estimated value are in question, whose effects are estimated reduction of water “losses” in transport from current 40% to about 20%.

Current problems

• complete construction area has not been comprised by the preliminary design
• section of main ducts has not been constructed
• there are streets where the distribution network has not been constructed
• inadequate water pipes (the profile of pipes, kind of material and physically worn-out state of materials) which need replacement (about 40 km)
• water shafts (about 290 pieces) to be reconstructed and to replace the equipment within them to be replaced
• lack of the sufficient number of mud drums and hydrants

Elements of development

• replacement of worn-out distribution network
• preparation of mathematical model of distribution network and the equipment of infrastructure with measuring devices
• construction of lacking distribution network