Also threatened is aquatic life in Lake Nakuru in which this fresh water river empties its polluted water.
Ironically, Egerton University, which has a department that offers courses on environmental science, one of them being waste management, is among the institutions releasing some of these pathogens (viruses or bacteria that are capable of causing diseases) and Faecal Coliform (FC) into the river.
A recent Environmental Impact Assessment (EIA), which was done by Prof Wellington Wamicha, a lecturer at Kenyatta University, found out that most of the pathogens in the Egerton’s sewage treatment plant find their way into the river despite going through oxidation dams, which are meant to arrest them.
A cunning factory located near the university and using oxidation dams to manage its wastewater suspected to contain chemicals has also been described as another culprit in polluting the river.
Prof Wamicha’s study shows due to pollution, the river has 24 times more the amount of pathogens recommended by World Health Organisation to be any waterway.
With 1,200 pathogen per litre compared to WHO’s approved of 50 pathogen per litre, the river is now said to be sagging from high concentration of these germs which may cause typhoid, dysentery and other intestinal infections to humans and animals using the water.
The pathogens are also making survival difficult for aquatic life in both the river and Lake Naukuru -where the river pours its water – as they deplete the available scarce oxygen.
Faecal Coliform (FC) levels at certain points in the river was too beyond the levels of 1000 FC per 100ml recommended by World Health Organisation (WHO) as appropriate for unrestricted irrigation. A faecal coliform count is used to measure the acceptable degree of pollution in any given waterway.
Another EIA by Egerton University’s department of environmental science warns that the amount of time the wastewater spends in one lagoon (oxidation dam) is very short for effective treatment to occur. Hence much of the raw sewage is discharged into the river, explaining the high FC.
Past research has warned that failure to treat wastewater well would occasion more than 500 bacteria, viruses and parasites travelling from human and animal faecal through water.
Likewise, the University’s EIA says the wastewater treatment lagoons constructed in 1950’s to cater for a population of 3,000 university staff and students is insufficient for the now blow-up population of 12,000 people.
To contain pathogens and FC amount in the water being released into Njoro River, the University uses two oxidation dams to treat its sewage and all other wastewater. It has also build another two new dams at cost of about 33 million to help manage wastewater from its 10,000 population of which an estimated 6,000 are students.
Oxidation dams are used for simple secondary treatment of sewage effluents and are designed to reduce the number of pathogens to levels not capable of causing disease in human beings or animals. These dams help degrade what is known as organic loading – faecal matter, urine, mucous, dirt, perspiration and body oils and grease – that serves as a source of food for pathogens and other organisms.
And because such dams are restricted to warmer climatic regions due their dependence on seasonal temperature changes, they are an approved cost-effective way of managing waste matter in tropical countries. WHO recommends that waste from oxidation dams discharge only 50 pathogens per litre into any water way.
According to Prof Wamicha, the oxidation dams being used by the University are meant to purify the waste matter and drastically reduce the amount of pathogens.
“ But we found out is that pathogens do not change at oxidation points and when released in the river, their concentration is still high.”
It is still difficult to place a finger at the wrong points responsible for allowing such amount of pathogens to pass through without dying.
Of concern also is the use of oxidation dams in waste management by a fruit-canning factory, which pour their waste into the River. Nobody knows if their dams are effective enough to arrest pathogens and chemicals, before the waste matter is poured into the river.
Literature elsewhere however shows that oxidation dams are generally inefficient and require large holding capacities and long retention times. If the waste matter does not stay in one pond for the recommended time, then it is likely to allow more pathogens to pass through. A probable explaination for the Egerton case.
Compounding the situation is the fact that some residents living alongside the river in areas like Njokerio, Sambaya and Mwigitu are also using it as an outlet to dispose of their waste matter. These areas are not connected to any municipal sewage system or water supply.
The piped water available is that from the boreholes, but most of them have failed because the level of underground water has gone down.
Matters are made worse during dry seasons when these boreholes completely fail and the river becomes the only salvation for residents as far as those in Njoro town. Students from Egerton University too are got in this web as they eat and buy some of their foodstuffs from areas like Njokerio, which use water from the river.
For others like the residents of Mwigitu village, the river is the only source of water after they were disconnected several months ago from borehole piped water. Some of these residents, unconscious of the pollution levels, do not even boil this water before using it.
“During dry seasons when the boreholes fail, I use the river water virtually for everything. Sometimes when I go to dig my Shamba several kilometres away I drink the water without boiling. It is therefore shocking to hear the river is polluted like this,” says one astonished woman, a resident of Sambaya.
Her friend who was standing beside her was not amused. She says to have witnessed, on several occasions, a worker at one of the institutions empting massive raw faecal contents in the river.
“ I have seen these person do it. But I usually fear if I raise alarm, the institution has what it takes to silence me.”
But things are likely to be better for these residents as Egerton University responds to drastically reduce the pollution of the river and improve ways of sustaining its water supply.
Authorities at the University in collaboration with Maji na Ufanisi, a local NGO specialising in water and environmental management, are coming up with a new technology that would radically reduce the amount of pathogens and FC getting into the Njoro river.
A three-year project meant to better wastewater management through what is known as Vegetative Wetlands, is being build using 50,000 US dollars (about Ksh 3.8 million) funding from United Nations Development Programme.
Touted as one of the best natural ways of managing wastewater and improving water quality, vegetative wetlands are a technology used to reduce bacterial pathogens such as salmonella and E.coli in wastewater. They are usually in the form of swamps, marshes, or bogs.
In the Egerton case, three wetlands being build on two acre plot of the eight acres plot set aside for the project, will have vegetation such as reeds, papyrus, duckweed, elodea, bulrush, acacia, and bamboo. When growing in a wetland, these species are known to curtail the survival of pathogens in wastewater.
A study by scientists at the Arizona University once found that water plants like duckweed significantly increased the die-off of bacteria responsible for typhoid and other intestinal problems.
At the Egerton treatment plant, an estimated 500 metres cubic of wastewater will go through three wetland cells, taking 14 days in each one of them before being discharged to the next. This means the wastewater is to take a combined 42 days in the three wetland cells.
Several studies elsewhere have shown that to eliminate pathogens responsible for typhoid and other intestinal infections, the wastewater has to stay in wetlands for a combined period of 20 days.
The principle behind wetlands is that as the water moves around plants growing in and around them, it allows the sewage and waste matter dissolved in the water to be absorbed by plant roots and pathogens to be trapped in the soil at the wetland basement.
This filtration process is said to remove much of the pollutant load by the time it leaves the wetland into any waterway. In addition, there are aerobic bacteria (which require oxygen and feed on pollutants such as faeces, urine and body fats at the surface of the wetland) and the anaerobic one (which survive in the absence of oxygen and degrade pollutants at the bottom of the wetland).
The university hopes by the time the wastewater goes through its oxidation dams and the three wetland cells, the amount of pathogens would have been reduced by between 80 and 90 per cent.
Which means the quality of the water arising from this process would have increased considerably. Indeed, once the system starts working, the university plans to use the water from the third wetland cell for irrigation and other purposes such as for toilet flushing or for laundries. Or for drinking purposes after treatment with chemicals.
The University also intents to use its wetlands as a source of income, as they will serve as areas for teaching, demonstration and research for environmental science students interested in the use of wetland wastewater management techniques. Besides, there are plans to rear fish as well as making the wetland act as a recreational and tourist attraction area.
In regions like South and North East Asia, wetlands are a lifeline for people there who use the wastewater for virtually everything especially for irrigation and fish rearing. India, for instance, channels its sewage into the estimated 3,000 hectares of wetland lagoons, in turn managing to produce 6,000 metric tonnes of fish every year from these wetlands.
In Israel, over 70 percent of the water used for big time irrigation schemes is one that has been recycled by use of wetlands.
Back at home wetland technique is being used at the popular Splash recreational centre and in Nanyuki flower farms.
For Egerton, the new technology would not only improve its environmental management, but will also cut costs as it will require two people to maintain compared to eight people being utilized by the current oxidation system.
After the project’s three years period lapses, Maji na Ufanisi Executive Director, Josiah Omotto says it would be handed over to the university to manage it for the rest of its life span.
The university’s deputy vice-chancellor, is already promising to extended the technique to the neighbouring communities which also have a problem in wastewater treatment. Some members of the surrounding communities are to occasionally participate in the maintenance of the University’s wetland to help them learn how the technology works.
“We are likely to help the communities to with expertise on how they can transfer the technology to their areas and use it treat wastewater,” says the Deputy Vice-Chancellor.
Far a field, Mr Omotto says they have earmarked Kibera and Kangemi slums as possible areas where the wastewater wetland technique can be applied.