Investigation of the Impact of Anti-Negative Pressure Facility on a Water Distribution System

High level water tank is a commonly used facility to satisfy water demand for people living in high building, which is also the so-called secondary water supply system (SWSS) in China. Due to lack of maintenance, water quality problem has been frequently reported in the SWSS. In the last few decades, anti-negative pressure facility (ANPF) has emerged as a revolutionary approach for solving the pollution in the SWSS. ANPF makes good use of the municipal pipeline pressure, which is the improvement of traditional water supply. However, most of recent research activities mainly focus on the influence of part of water distribution system (WDS). In this paper, the software of EPANET has been applied in the SWSS calculation and simulation. Besides that, the SWSS with ANPF simulation method is proposed to evaluate the effect of other all nodes 'pressure in the WDS using hydraulic model. As the cases study, the paper analyzed two WDSs with ANPF. After simulation of the SWSS, the result of WDS, which is smaller, indicates that 6 out of the 9 nodes are affected with ANPF and that of WDS, which is larger, demonstrates that 37 out of the 41 nodes are affected and the affected nodes are focused on the confluent of pipes, especially around the ANPF.