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Clogged Sewers Pose Health Risks to Residents

Wednesday August 14 2013

Dr Robert Ayisi, Nairobi County director of health. PHOTO/FILE

Dr Robert Ayisi, Nairobi County director of health. PHOTO/FILE 


The construction of highrise residential buildings could be seen as the answer to the housing crisis in Nairobi, however some of them pose a danger to the environment.  This is because they lack appropriate sewerage systems resulting in the disposal of waste water into open drains.

Overloaded Sewerage Systems

Although Nairobi County government is mandated with enforcing construction laws, rogue developers continue to put up buildings in disregard of planning regulations thereby choking the already overloaded sewerage system.

Dr Robert Ayisi, Nairobi County director of health says the broken sewers pose a health hazard because spillage of waste water onto roads, houses and other places can result in disease outbreak especially when it mixes with water for domestic use.

“During the rainy seasons, some of Nairobi’s estates flood with sewage because of the overflowing open manholes.  Dumping of solid wastes in open manholes and construction of illegal buildings on sewer lines results in clogged systems which pour effluent into the streets,” he says.

Predictions are that the sewerage system will be clogged even more when the city’s population is expected to hit the 20 million mark by 2020.


Over flowing Sewerage

In other instances, the septic tanks overflow because they are too small for the flats they serve. This is common in Nairobi’s Eastlands.

Solomon Kioko, a planner says the existing city sewer system, built in 1961 was meant to serve less than one million people and stretches about 163 kilometres.

“The sewer line is less than 30 per cent of the city’s total 696 square kilometres and only 20 per cent is connected to the sewerage system. It is regrettable that planners make provision for sewer lines but developers ignore this and build on them. The result is the mess we have,” says Kioko. He says the new county government should act by fining developers who disregard the city planning department’s guidelines and demolishing houses built on sewer lines.

Last  May, the Athi Water Services Board commissioned the construction of a new sewerage system in the city dubbed the Nairobi Sewerage Improvement Project.

Mr Malaquin Milgo, the Athi Water Services Board chief executive says the proposed project aims to expand access to sewerage services to city residents from 40 per cent to 59 per cent by next year. “The current sewerage system covers a mere 25 per cent of the area while serving only 40 per cent of the population. The three-year project will include rehabilitation and expansion of treatment plants, old trunk lines and laying of new ones in some areas with secondary and tertiary reticulation,” says Mr Milgo.


He says the project will increase sewerage coverage in Nairobi to about 50 per cent in the next five years. The proposed trunk sewers of various pipe diameters are expected to cover about 60km within the riparian reserve of selected rivers in Nairobi area.

Late year the National Environmental Management Authority (Nema) reined in on landlords in Zimmerman, Umoja, Embakasi, Mlolongo, Ongata Rongai and Dagoretti over poor drainages.

It ordered them to build septic tanks where there were none and expand capacities of small ones in one month.