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This study investigated the transport and mobility of Co(II) in swampy agricultural soil (SS1), soil from waste dump site (SS2) and soil from automobile repair shop site (SS3) all from Bambili-Cameroon. Column filtration experiments with Co(II) concentrations of 10, 100 and 500 mg/L were used. Breakthrough curves were used to evaluate Co(II) mobility. At 10 mg/L, Co(II) there was no mobility for all three soil samples, at 100 mg/L, no mobility was observed in SS2 but 6.398 mg/L and 2.081 mg/L of Co(II) detected in the effluent of SS3 and SS1 respectively. Cobalt transport was faster in SS1 with 9180 mL of effluent collected in 2331.59 min followed by SS3 with 1545 mL of effluent collected in 2072.59 min and lowest in SS2 with 1040 mL of effluent collected in 2356.49 min. No saturation point was reached for any of the soil samples despite filtration for over 2500 min on average. For SS1, maximum C/C0 was 0.5 for 100 and 500 mg/L and 0 for 10 mg/L. For SS2, maximum C/C0 was 0.3 for 500 mg/L and 0 for 10 and 100 mg/L. For SS3, maximum C/C0 was 0.6 for 500 mg/L in 2000 min and 0.1 for 10 and 100 mg/L in 2500 min. When the soils were acidified with 0.5 M H2SO4, the breakthrough times reduced from about 2500 min to 8, 132 and 27 min for SS1, SS2 and SS3 respectively for 500 mg/L and soils saturating in about 1000 min. The order of Co(II) transport is SS1 > SS3 > SS2 and mobility is SS3 > SS1 > SS2. These results for Co(II) mobility tie with the sandy fractions of 58.7, 55.1 and 65.6% for SS1, SS2 and SS3 respectively with corresponding gravel of 3.6, 5.2 and 5.9% while those of Co transport tie with soils bulk densities of 0.09, 1.2 and 1.0 g/cm3 for SS1, SS2 and SS3 respectively. A surveillance system should be installed in zones where these activities are taking place to check and provide timely remediation techniques to eliminate heavy metals pollution.

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