What you need to know:
- The NCWSC explained that the shutdown of Ng’ethu treatment plant was occasioned by heavy rainfall of more than 79mm in the Aberdare Ranges, the facility’s main catchment area.
- This resulted in increased river flow which caused high turbidity – a reduction in water clarity due to presence of suspended particles – and clogged the system.
Nairobi has announced a two-day water supply interruption following the shutting down of the city’s main water treatment plant.
Nahashon Muguna, acting Managing Director of the Nairobi City Water and Sewerage Company (NCWSC), explained that the shutdown of Ng’ethu treatment plant was occasioned by heavy rainfall of more than 79mm in the Aberdare Ranges, the facility’s main catchment area.
This resulted in increased river flow which caused high turbidity – a reduction in water clarity due to presence of suspended particles – and clogged the system.
“There has been increased river flow causing very high turbidity in the raw water, which is flowing slurry and is suspected to be caused by a landslide upstream," Mr Muguna said.
"This has necessitated closing of the water treatment plant to avoid transmission of water which does not meet World Health Organization standards."
Mr Muguna noted that Ng’ethu, which serves 85 per cent of Nairobi’s population, is designed to treat water efficiently if it is of less than 800Ntu (turbidity).
He said the water currently flowing into the plant has failed to respond to chemicals used to treat it.
Mr Muguna said the city was receiving water from Sasumua, Kikuyu Springs and Ruiru Dam.
This accountes for just 15 per cent of the entire water production capacity, meaning about the entire city and its environs would experience the interruption.
This, he said, will see supply interrupted in the Nairobi central business district, University of Nairobi's main campus, the Coca-Cola factory, Jomo Kenyatta International Airport (JKIA), the EPZ in Athi River, areas along Mombasa Road such as South B, South C and surrounding; the whole of Industrial Area and areas along Kangundo Road including Ruai, Njiru, Kayole and Komarock.
This is in addition to areas along Juja Road such as Mlango Kubwa, Mathare, Eastleigh, Moi Airbase, Huruma, Kariobangi, Pangani; areas along Jogoo Road covering Maringo, Buruburu and surrounding estates, Bahati; and areas along Outering Road including Baba Dogo, Dandora, Umoja, Donholm, Fedha, Tassia, Avenue Park, Nyayo and Embakasi.
Others are areas along Thika Road including Kenya Breweries, Kenyatta University, Kahawa Barracks, Kasarani, Mwiki, Kahawa Sukari, Garden Estate and Thome Estate and lastly areas along Limuru Road covering Parklands, Ngara area, Aga Khan Hospital, University of Nairobi Law School and City Park area, United Nations, Gigiri and Muthaiga.
A statement from the NCWSC said it was expected that supply would be restored by 6pm Friday but Mr Muguna told the Nation that some parts of the city would lack water for two days.
“The intake works is clogged with logs and the water is not responding to chemicals to enable it settle suspended materials and remove the colour," he said.
"We are unclogging the intake before we restart production. When we shut down the system for a whole day, it means the following day will be affected."
However, the official said, works to ensure normalisation of the treatment process were underway.
“Whilst every effort will be made to restore the supply of water, we request all customers to use their stored water sparingly,” said the acting MD.