Reducing the amount of aluminium sulphate used for the coagulation process during water treatment process at Luweero Industries Limited by using a bio coagulant(cactus powder)

Abstract

This research was carried out at Luweero Industries Limited. It aimed at reducing the amount of alum coagulant used for water treatment by using a bio coagulant (cactus powder).The turbidity removal/coagulation activity of three coagulants; alum, cactus powder and a combined coagulant (cactus powder + alum), and their effect on other parameters of pH, Electrical Conductivity, and color of raw and clarified water samples were investigated. The parameters of turbidity, pH, Electrical Conductivity, and color of clarified water were determined using the jars test method. The water sample was collected from Lake kyoga. Four different concentrations of each coagulant, 1.0%, 1.5%, 2.0% and 2.5% were prepared and each was used with the jars test experiment to determine the turbidity removal, pH, electrical conductivity and color of clarified water. The results for each water sample were determined and tabulated as shown in the tables below. The results were taken. Alum turbidity removal was found to be 93.78% . Cactus powder turbidity removal was found to be 89.23% ,and interestingly, a combination of cactus powder and alum gave the highest turbidity removal of 94.39% . Alum coagulant significantly lowered the pH of water from 7.65 at 0% to 4.5 at 2.5% concentration, however cactus and a combination of cactus and alum marginally affected the pH of water. Electrical conductivity increased from 117.90μs/cm to 177.0 for alum, 117.90 to 136.67 for cactus coagulant, and 117.90 to 138.65μs/cm for a combined coagulant (alum and cactus). The color of water decreased from 124.65PtCo to 13.00PtCo for Alum, 124.65PtCo to 16.00PtCo for cactus, 124.65PtCo to 12.80PtCo for a combination of cactus and alum. Therefore, a combination of alum and cactus powder is a very good coagulant and is recommended for use in water treatment than using alum alone. This would even further reduce the amount of alum required for coagulation hence a reduction in cost of purchasing alum, residual alum in water would be reduced and hence it’s harm on human beings, and less alum would be introduced to the environment.