| dc.description.abstract | The Babati Urban Water Supply and Sanitation Authority (BAWASA) in northern Tanzania
supplies water from the Kou River to Magugu town for domestic purpose, where its Fe (3.64
mg/L) and turbidity (87 NTU) concentrations were found in excess beyond their acceptable
limits. A coagulation-flocculation-sedimentation water treatment plant was planned to be
installed for treating the water, where the system’s performance is negatively influenced due
to inadequate applications, hence requiring optimization. The quality of sediment and water of
the Kou River was examined for physicochemical parameters and 9 metallic elements. The
water did not meet the requirements for aquatic, biological life, and irrigation purposes for at
least 1 metallic ion. Furthermore, pollution levels of the 9 metals in the river sediments were
evaluated using 6 pollution indices and a moderate contamination was found, hardly posing
ecological risk. A coagulation-flocculation-sedimentation water treatment system was
optimized to respond to coagulant dose, pH, mixing rates, mixing time, and settling time in the
removal of Fe and turbidity using jar-test. The optimum dose and conditions were: 30 mg/L
alum, an initial mixing rate of 150 rpm for 5 minutes, slow mixing rate of 20 rpm for 30
minutes and settling time for 30 minutes which was validated using scale-up pilot test and
resulted in 98.25% turbidity and 97.5% Fe removal. Furthe research on developing enhanced
time-saving optimization method and developing a dose indicator technology to assign alum
dose requirement based on the fluctuating characteristics of the raw waters (turbidity) is
recommended. | en_US |
