Water Quality Enhancement Programme [ Back to Main ]
The conventional cheap method of cleaning pipelines is by flushing the mains or reticulation pipes with large quantities of clean water through unidirectional flushing. The Air Scouring Programme (ASP) is designed to systematically clean all the reticulation pipes of diameter 200mm or less using compressed air. A total of 29 air scouring machines have been purchased for this purpose.
Air scouring works by using filtered compressed air, injected into the mains via hydrant or air insertion point to propel a small volume of water at a high velocity. When the valve upstream of the air entry point is opened slightly, the filtered compressed air mixing with water creates a vortex that travels through the isolated section removing sediments, bacteriological slimes or biofilm and soft mineral scale through a scour point at the other end of the reticulation system. After water exiting the line is clear, only then water supply is restored to the pipe section.
Photographs showing the conditions during and after the cleaning using air scouring method.
Before Cleaning Work After Cleaning Work
Photographs showing air-scouring procedures being implemented by SYABAS
Air Scouring Method: Arrangement of Equipment & Valves
In 2014, a total of 7,296.81 km (data as at 31st December 2014) of air scouring works were performed at districts’ workable ASP Zones. The changes made to the cleaning time period (cycle/frequency) from 6-month cycle in 2008 to 12-month cycle in 2011 was mainly due to the reduction in water quality complaints. However, about 34% of the reticulation main pipe systems could not be cleaned by the air scouring method and have been declared as non-workable ASP Zones due to the unavailability of air insertion, isolation and scour valves in the ASP Zones. It was projected that these valves and fittings would be installed in stages starting from 2008 onwards depending on the available budget under CAPEX.
The ASP cleaning of the reticulation system had contributed to the reduction in water quality violations and also consumers’ water quality complaints.
Table- Air Scouring Works from Year 2010 until 2014
|Length of Reticulation Pipes Cleaned (km)
Water Quality Enhancement Programme: