Reduction of water age in drinking water supply networks of small settlements

Abstract

At the end of the last century the transformation of the system and economic structure led to unavoidable and significant overcapacity in our drinking water supply systems. The situation was particularly severe in small settlements, where the supply of fire-fighting water originally required large pipe diameters and where unnecessary capacities were further strengthened by trend of population decrease. Over-dimensioning increases the water age, the residence time in the system, giving rise to secondary water quality degradation. This caused a critical situation when it was not enough to provide drinking water quality at the treatment plant. Drinking water quality must remain at the consumer taps. The process is accompanied by a deteriorating technical state of the network age and the associated increased water losses in the network. Renewal of networks will become inevitable in the near future. The reconstructed pipes, if their
diameters should meet the requirements of fire-fighting, preserve the oversized state. Therefore, the small settlements should discontinue the water demand of firefighting with the drinking water system. This is possible with the installation of storage tanks. Estimations based on a national database show that the reconstruction of a total of 13.111,632 km long pipelines of 2.051 small settlements, sized for realistic drinking water consumption, at a price level of 2016
requires 260-270 billion HUF budget resource if a lining with continuous pipe and for firefighting purpose we apply water tanks of 30 m3 at every 200 m along the pipes.