Conceptual Improvement of the Existing Primary Sewerage System with a Vacuum System in the Dokležovje Settlement

Today, we cannot imagine life without clean water, which is also facilitated by the proper construction and operation of various types of sewerage systems. Depending on the terrain configuration and geological characteristics of the soil, we decide on the type of construction. For the existing part, they described the key elements of the sewerage line and provided their characteristics and lengths. ** After all the theoretical knowledge, they embarked on the conceptual improvement of the existing situation** and comparisons with the vacuum system. Consequently, we find that this also shortens the construction time of the vacuum pipeline. When analysing the comparison of operating and maintenance costs, we find that vacuum sewerage is more rational.

Problem

Today, we cannot imagine life without clean water, which is also facilitated by the proper construction and operation of various types of sewerage systems. Depending on the terrain configuration and geological characteristics of the soil, we decide on the type of construction. If the terrain allows, we build gravity drainage.

In predominantly flat areas, pressure sewerage is recommended. Vacuum sewerage has none of these limitations, as it operates under pressure and can be built even in challenging terrain. In the diploma thesis, they first briefly described the types of sewerage systems we know.

Solution and Method

For the existing part, they described the key elements of the sewerage line and provided their characteristics and lengths. After all the theoretical knowledge, they embarked on the conceptual improvement of the existing situation and comparisons with the vacuum system. Finally, they presented the construction of both sewerage systems for the Dokležovje settlement from a financial and time perspective. During the construction of the gravity and pressure sewerage at that time, ** questions arose**: "Why such excavation depths, interventions in nature, large asphalt removals? …".

These very questions prompted us to think about how to implement a better sewerage system that would be technically simpler and consequently more cost-effective, both in construction and in subsequent maintenance and operation. With the bill of quantities and calculations, they proved that the investment in the construction of a vacuum system would be more cost-effective than the classic gravity system. The greatest savings would be made in earthworks and landscaping works, as the implementation of a vacuum system does not require such widths and depths of excavation.

Results

Consequently, we find that this also shortens the construction time of the vacuum pipeline. When analysing the comparison of operating and maintenance costs, we find that vacuum sewerage is more rational. On an annual basis, the operating and maintenance costs for the vacuum system are lower than for the gravity system.

Regarding the elimination of faults and defects in sewerage systems, the vacuum system is more reliable. Faults are identified through monitoring, whilst the gravity system requires a physical inspection of the canal or searching for the defect, only then eliminating the fault and repair. Whilst writing the diploma thesis, they learnt about the ** numerous advantages** of vacuum construction of sewerage systems.

It convinced us in many areas. It is suitable for construction in flat areas, as with the sawtooth profile of pipe laying below the frost zone, we do not need great depths; it is also suitable for unfavourable conditions, e.g. rocky terrain, crossing watercourses or existing utility lines, protected areas where minimal construction interventions are required, and in terrain with high groundwater. The prices of construction works and materials must be mentioned.

Unfortunately, we still live in the era of the so-called "construction recession", which is most reflected in the prices of construction works. We observe that prices, e.g. for earthworks or construction works, have not changed significantly since 2008, which we attribute to the fact that the company wants to remain competitive with other contractors.

We can say that the prices for work performed are low compared to the prices of materials, which we cannot influence, as they are determined by the manufacturer. At the conclusion of the diploma thesis, we can confirm that the vacuum system for sewerage construction in the Dokležovje settlement is a more cost-effective solution for wastewater drainage, both from an economic and technological perspective. In the times we live in, the value of investment has great significance and impact on the individual.

We believe that in their case, with the more cost-effective variant "Vacuum Sewerage", they would build a reliable, watertight and environmentally friendly sewerage system.