Monitoring and Counting E. coli Bacterial Growth During Low-Pressure Events in Drinking Water Distribution Networks

Maintaining clean drinking water is a key factor in maintaining sustainable development and a healthy environment. In addition to monitoring water quality at water tanks, it is important to monitor water distribution network (WDN) and pipes where water is being transported. Intrusion in WDN can be triggered by transient low-pressure events. This intrusion may result in the contamination of drinking water supplied to consumers, which may have major health impacts. This experimental study was performed to monitor and count E. coli bacterial intrusion into WDN. Two experiments were performed to investigate (1) the effect of low and negative pressure in WDN on bacterial intrusion; (2) the propagation and growth of bulk bacterial intrusion in WDN; (3) premeditated bacterial contamination of water sources (tanks). It was found that the rate at which bacteria reaches customers is very comparable however, higher risks are found with premeditated bacterial intrusion. It was also found that there is a small chance for E. coli bacteria to be intruded into the system after sudden low/negative pressure events. The experiment shows that high pressure within water networks pumps out water of the system then the mixture (water and contaminants) is sucked back into the network. It was observed that contaminants were not able to be significantly intruded into the system if water pumps were shut down for a short period of time. The minimum time required for contaminant to be intruded into the system was found to depend on the water pressure prior water pumps which were turned off.