What is eWQMS?

Emanti Management's Water Quality Management System (eWQMS) can be used to guide the tracking, reviewing and improving of water quality.

From the storage facilities treatment facility, drinking water enters the reticulation or distribution system and passes through a series of pipes to the water pipes connected to customers. As a result of lengthy distribution pipe structures in the delivery system (often kilometres long), connections with industrial users, the potential for tampering and vandalism, leaking pipes, old infrastructure, intermittent operation, etc opportunities for microbiological and chemical contamination exist. The quality of the water in the distribution system may therefore deteriorate if proper maintenance and management is not undertaken. Contamination can occur within the distribution system in the following ways:

  • When contaminated water in the subsurface material and especially nearby sewers surrounding the distribution system enters because of low internal pipe pressure

  • When contaminated water is drawn into the distribution system or storage reservoir through backflow resulting from a reduction in line pressure and a physical link between contaminated water and the storage or distribution system

  • Through open or insecure treated water storage reservoirs and aqueducts, which are potentially vulnerable to surface runoff, faecal contamination by animals, and may be insecure from vandalism and tampering

  • Through pipe bursts when existing mains are repaired or replaced or when new water mains are installed, potentially leading to the introduction of contaminated soil or debris into the system

  • Through human error resulting in the unintentional cross-connection of wastewater or stormwater pipes to the distribution system or through illegal or unauthorized connections

  • Through leaching of chemicals and heavy metals from materials such as pipes, jointing compounds, taps and chemicals used in cleaning and disinfection of the distribution system

Biofilms in pipelines result when micro-organisms grow on the inner surface of pipes. This occurs particularly when nutrients levels are high and disinfectant residuals are low. Pathogens may accumulate in biofilms, resulting in possible contamination.

Considering the above it is important that the distribution system itself provides a secure barrier to contamination as the water is transported to the user. In order to ensure that the water provided to consumers is of an acceptable quality, effective maintenance and management (including water quality monitoring) is necessary. This includes ensuring the system is well designed and operated, maintaining appropriate free chlorine residuals, implementing maintenance programmes to detect and repair leaks, flushing to remove accumulation of internal deposits, etc. When systems are flushed, it is important that the section to be flushed is isolated from the rest of the system and that there is sufficient pressure and water in the system (otherwise will require additional pumps and storage tanks). The section can be flushed by opening the stop valve on the supply side slowly, and opening the washout valve on the remote end. Water should be injected through the pipe section continuously for a suitable period (usually about 15 minutes) to stir up deposits inside the water main and flush all silt out. Flushing water should be directed away from the traffic, pedestrians and private plots. Two water samples from each hydrant (about 2 to 3 minutes after the hydrant was opened), one at the beginning and the second sample when the dirty water is assumed to be clean (just before closing the hydrant) should be collected for analysis. If the analysis indicates that the water quality is not yet satisfactory, the procedure should be repeated.

At point if use, it is important that consumers ensure that proper hygiene is followed including ensuring that hands, taps, household containers, etc are kept clean. This will ensure that the drinking-water supplied by the Water Service Authority is safe for consumption and that no ill effects arise.