Abstract:
Groundwater is the only Water Supply for Asossa Town. Small amounts of iron are often
found in water supply because of the large amount of iron present in the soil and corrosive
water will pick up iron from pipes. The problems caused by the presence of large
concentration of iron impart a metallic taste to the water, Industrial products such as
paper, textiles, or leather may be discolored .Ground water samples collected from Asossa
Town deep well relatively with higher iron (Fe) concentration than the permissible limits
as specified in WHO. The naturally available environmentally and economically
acceptable zeolites were obtained from the surrounding area of the Town. It was a powerful
Adsorbent for the removal of iron. The aim of study was to design the most efficient, easily
available, economical and environmentally acceptable iron removal technology from
ground water using natural zeolites. The study was carried on Laboratory-scale columns
experiment by sand filters with variable depths of 10, 15, 20, 25, 30 cm and three graded
types of sand (course, fine and graded) were used. The course sand (E=1.0 mm, U=1.117,
depth of sand =30cm, filtration rate 2.4 m3
/m2
/hr.) was the best type of filter media. Iron
concentration measured in groundwater was 5.15 mg/l before filtration and decreased to
concentration of 0.85 mg/l following filtration. Hence, iron removal efficiency of 83.49 %
with a correlation coefficient of R
2>0.98 was obtained during aeration process. The result
compared with chlorination and aeration depending on sand filtration, chlorination was
better removal efficiency in natural zeolites than aeration filtration process. According to
Ethiopian standard water quality procedure and WHO guideline states that Fe
concentration <0.3 mg/l is permissible level for drinking water. In this study also
chlorination treated water initial concentration 6.20 mg/l after sand filtration 0 mg/l iron
concentration ,then the removal efficiency of course sand was 100% , its correlation
coefficient,R2>0.97. Advantage of such treatment were simplicity, easily available natural
zeolites, low cost design at house hold and a community level, and without the need of
chemical addition. Finally, periodic washing for sand filter or replacement of sand by other
sand was needed in order to get sufficient flow rate.
