Minimising the number of Flocs in clarified water by application of the Polyaluminium chloride. (case study. Luwero Industries Limited)

Abstract

Raw water contains suspended and collidal particles that affect the turbidity of water and hence the filtration process by clogging filters if not done processing beforehand. One of the way to reduce the contaminamts in raw water is the process of physically-chemical treatment using coagulation processin the water treatment plant and the coagulation process requires coagulant optimally capable of removing the suspended and collidal particles in water treatment. The purpose of this research is to minimise the number of flocs in clarifird water to reducing clogging of sand filters by use of polyaluminium chloride as the coagulant in turbidity reduction so that the turbidity results for clarified water comply with the standard value of <5NTU. The study was conducted with the study of literature. The coagulant forms fine precipitating or settleable solids with the suspended matter, the solid formed agglomerate into flocs which settle at the buttom of sedimentation tank. The Jar test was performed using the flocculator machine. Different stock solutions of the coagulants were prepared and different concentration put in different jars and the machine run to ontain the results. These resullts were then used to get the better coagulant between Alum and PAC, the turbidity results proved that PAC could be a better coagulant. In terms of the cost Alum is cheaper than PAC , but considering the total cost of water treatment PAC becomes cost effective. Therefore in the coagulation process of raw water is recommended to use PAC as the coagulant.