Replacement of aged city water pipes… GWI to mapping technology on its distribution lines

Jun 29, 2019 News

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Guyana Water Incorporated (GWI) has been working to upgrade the aged pipe infrastructure in the capital city of Georgetown in order to further improve the level of service and quality of water customers receive.

According to the company, it has been speaking to the issue for the past two and a half years and has been working to incrementally replace the pipelines in the Georgetown network.
“The Cast Iron and Asbestos Cement pipes which are being replaced have become encrusted over decades and have exceeded their lifespan. Many of the pipelines are over 100 years old, and due to this, there is also a high iron content being released, thereby compromising water quality. They are being replaced with Polyvinyl Chloride (PVC) and High-density Polyethylene (HDPE) pipes which present a much lesser chance of encrustation.”
GWI said that customers can be assured that upon completion of works in respective areas, there will be an improved level of service and water quality.
“As further work is executed in adjacent communities, the full benefits will be experienced in the entire area.”
Pipelines are being replaced on Sheriff Street, forming part of the ongoing road expansion works. Some 500 metres have been installed thus far and upon completion, the pipelines from the junction of Sheriff Street and the East Coast Demerara Public Road to Cross Street, Alexander Village would have been replaced.
GWI said that the Albouystown community is also one which has old asbestos mains which are porous and tuberculated.
“Tuberculation is the development of small mounds of corrosion products on the inside of iron pipes.”
GWI has also installed new pipelines on James Street from Saffon Street to the clinic in the area and a new phase of the project is scheduled to commence on July 9, 2019.
Works for the new phase, the state-owned company said, entails the installation of pipelines along the remainder of James Street and the cross streets.
Meanwhile, works are ongoing to improve the level of service to customers through the installation of new transmission mains and replacement of distribution mains in a number of areas between Lamaha Street and GWI’s head office located on Vlissengen Road.
GWI is also working to replace transmission mains on Church Street, a project which is in its planning stage and will entail the installation of some 2000 metres of pipelines.
“During the interconnection of the pipelines, customers of Central Georgetown will experience a reduced level of service for a short period in order to facilitate these works. The replacement of the pipelines allows GWI to place the new lines closer to the fence line as opposed to under roadways, making them more accessible for repairs in the future.”
Upon completion of the installation of the pipelines in the various areas, GWI said will be utilising Geographic Information System (GIS) technologies to map all of the assets, including gate valves and pipelines so that the company has precise information on their location for future use and access.
“An essential aspect of pipeline rehabilitation is the maintenance of the integrity of water quality during and following completion of the works. During the excavation and laying of pipelines, there is the possibility of an open end through which contaminants may enter.”
During the actual placement of the lines this may also occur. However, there are approaches to ridding the lines of whatever contamination may have entered, GWI explained.
“Flushing of the pipelines is commonly employed as a means of expulsion of sand and clays. Shock Chlorination (disinfection at high dosages) is also done to target microbial contamination. This entails filling the lines with heavily chlorinated water for a period of eight (8) to twenty four (24) hours.”
This is then flushed out until a free chlorine residual of 1 milligram per litre is achieved and a sample taken to assess the microbial quality.
“Once there is no indication of contamination, the laboratory approves the interconnections to the existing network. The aged infrastructure in the city has been the cause of numerous breakages within recent years, costing GWI millions of dollars.”
When these breakages occur, there are lengthy disruptions to the water supply since the successful repairs require the Shelterbelt Water Treatment Plant to be shut down during that period.
“Further to water supply, breakages can also compromise water pressure and water quality. As the water production is increased in the city, the way is paved for the water pressure to be increased, which can cause breakages as well. Thus far for 2019, there have been 34 major breakages in Central Georgetown, 19 of which can be attributed to the aged infrastructure and 15 due to external parties.”

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