Browsing by Author "Kaluli, J.W."

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    Physicochemical Characteristics of undrainable Water Dams Utilized for Fish rearing In The Semi-Arid Naromoru Area, Central Kenya
    (Jomo Kenyatta University of Agriculture and Technology, 2012) Mwangi, Benson M.; Kairu, E.; Ndiwa, C.T.; Kaluli, J.W.; Nyingi, D.
    Naromoru is a semiarid area in Central Kenya, occurring on the leeward side of Mt. Kenya. Its water sources include a few permanent rivers such as Nairobi River, intermittent streams and a large number of undrainable water reservoirs. Most of the undrainable water resources have been stocked with fish but their utilization for fish rearing has generally remained very low. The purpose of this study was therefore to examine the water quality status of the dams to assess their suitability and potential for fish production. pH, electro-conductivity and total dissoved solutes (TDS) were measured in-situ from three reservoirs (Gathathini, Lusoi and Kianda dams) differing in their habitat characteristics. Water samples were collected for determination of the ionic concentartions of the reservoirs. Water quality status differed markedly between sites, with electric conductivity ranging from 350μScm-1 at Gathathini dam to over 1350μScm-1 at Lusoi dam. pH however showed only a slight variation from 8-9.6. Water temperature and transparency varied significantly between the sites, while cationic constituents (Ca2+, K+, Mg2+ and Na+), anions (SO4 2-, HCO3 2-, and Cl-1), heavy metals (Pb2- and Cu2+) and nutrients (NO3 - and PO4 2-) were all within the recommended WHO levels for fish production. Generally the water quality status was within the standards recommended for fisheries production
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    Towards a national policy to support wastewater reuse in Kenya
    (2011) Mwangi, Benson M.; Kaluli, J.W.; Githuku, C.; Home, P.
    Kenya is a water-scarce country with the capital city, Nairobi, receiving less than 100 l/capita/day. Potable water for irrigation and industrial use is generally unavailable, and this calls for alternative water sources. Despite use of wastewater being illegal in Kenya, it is used to irrigate over 720 ha in Nairobi. In order to justify the formulation of a national policy to support wastewater reuse, secondary data which included the authors’ previous work was reviewed. In a study done between 2006 and 2007, the levels of nitrates (100 mg/l) and TDS (630 mg/l) in the wastewater were found to be within the acceptable NEMA standards. The concentration of lead was 0.1 mg/lwhile cadmium and chromium were non-detectable. However, levels of BOD and Coliform bacteria were higher than NEMA limits. This implied that Nairobi sewage needed to be treated for the removal of BOD, turbidity and microbial contamination. In order to allow for safe use of wastewater in Kenya, there is need to formulate a national wastewater reuse policy which provides guidelines for maximum allowable levels of pesticides, herbicides, and heavy metals in wastewater reuse. Such a policy should also indicate the required water quality monitoring frequency for faecal indicators (Escherichia coli, faecal coliforms, enterococci), and suggest the maximum allowable concentration of nutrients (nitrogen and phosphorus) which may are usually abundant in wastewater.