Abstract :
Access to safe drinking water is important as a health and development issue at national, regional, and local levels.
About one billion people do not have healthy drinking water. More than six million people (about two million
children) die because of diarrhea which is caused by polluted water. Developing countries pay a high cost to
import chemicals including polyaluminium chloride and alum. This is the reason why these countries need low-cost
methods requiring low maintenance and skill. The use of synthetic coagulants is not regarded as suitable due to
health and economic considerations. The present study was aimed to investigate the effects of alum as coagulant
in conjunction with bean, sago, and chitin as coagulants on the removal of color, turbidity, hardness, and
Escherichia coli from water. A conventional jar test apparatus was employed for the tests. The study was taken up in
three stages, initially with synthetic waters, followed by testing of the efficiency of coagulants individually on
surface waters and, lastly, testing of blended coagulants. The experiment was conducted at three different pH
conditions of 6, 7, and 8. The dosages chosen were 0.5, 1, 1.5, and 2 mg/l. The results showed that turbidity
decrease provided also a primary E. coli reduction. Hardness removal efficiency was observed to be 93% at pH 7
with 1-mg/l concentration by alum, whereas chitin was stable at all the pH ranges showing the highest removal at
1 and 1.5mg/l with pH 7. In conclusion, using natural coagulants results in considerable savings in chemicals and
sludge handling cost may be achieved.
