Comparing the Coagulation Performance of Rice Husk, Cypress Leaves, and Eucalyptus Leaves Powders with That of Alum in Improving the Turbidity and pH of Some Local Water Sources in Bamenda, Cameroon

Abstract

In this study, the efficiencies of the use of rice husk, cypress, and Eucalyptus leaves biocoagulants as alternative to alum as chemical coagulant in reducing turbidity and stabilizing the pH of slaughterhouse wastewater and three other local drinking water sources were investigated. Two systems were used: one involving individual coagulants and the second involving mix alum and biocoagulant with fixed alum dose of 0.05 g and varying amounts of each biocoagulant type (0.05 to 5 g). Turbidity reduction, coagulation activity, and pH variation were used to characterize each system. Results show reduction in turbidity is higher in mixed coagulants than with individual coagulants. At 5 g each of alum, rice husk, cypress, and Eucalyptus leaves, the corresponding turbidity values, 8.3, 13.6, 14.5, and 20.3 NTU, were obtained compared to 7.3 with 0.05 alum and 5 g rice husk mixture, 8.7 NTU with 0.05 g alum and 5 g cypress leaves mixture, and 16.1 NTU with 0.05 g alum and 5 g Eucalyptus leaves mixture, for 37.3 NTU initial turbidity. The used biocoagulants individually show insignificant effect on the pH of coagulation-treated water. Alum has an insignificant effect up to 2 g. 0.05 g of each biocoagulant stabilizes the pH between 6.57 and 7.34 against 4.14 for alum. 0.05 g alum/0.05 g biocoagulant stabilized the pH of water between 6.32 and 7.41. The coagulation activities for individual systems follow the order alum > rice husk > cypress > Eucalyptus, and for mixed systems, alum/rice husk > alum/cypress > alum/Eucalyptus. Water with turbidity and pH values within the World Health Organization’s guideline value of < 5 NTU and 6.5–8.5, respectively, were obtained using studied low cost and locally available biocoagulants.