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s: Despite the many services that natural rubber provides to humanity, its production generates significant quantities of polluted effluents which have a negative impact on health and the environment. In order to reduce this pollution and allow water to be reused after treatment, a synthetic effluent treatment trial was carried out in a submerged membrane bioreactor in the presence of two strains of yeast (Yarrowia lipolytica, Pichia guilliermondii) and biodegradation parameters (COD, NH4+, NO2-, NO3-) were followed. The Mohlman Index (MI), the particle size distribution, the Lowry method for proteins and the Dubois method for sugars have made it possible to characterize the sludge generated during biodegradation. It appears from these experiments that the reduction rate of COD was 98% and that of nitrification and denitrification 90%. There is a decreasing linear relationship between the MI and SS (Suspended Solids) with an R2 of 95%. The distribution of the particle size of the sludge is tri-modal with a maximum of sludge having an average size of 1000 µm. The sludge formed resists filtration with a polysaccharide/protein ratio of 0.45.

The presence of arsenic at relatively high concentrations in water as a result of natural and human activity discharges requires proper treatment before use. Arsenic was analyzed using a spectrophotometric method. Experiments were carried out in a column packed with natural pozzolan (black, red) from Djoungo (Cameroon) at different pH (5, 7, 9), initial arsenic concentration (100 μg/L, 200 μg/L, 400 μg/L) and flow velocity (0.39 cm/min, 0.79 cm/min, 1.57 cm/min). Results showed that the bed saturation time (outlet concentration from the bed ≥ 10 μg/L) is longer for a lower pH, flow velocity and initial arsenic concentration. Two kinetics models; Adams-Bohart and Thomas were applied to the experimental data to predict the breakthrough curves using linear regression and to determine the characteristic parameters of the column. The Thomas model was found appropriate for the description of the whole breakthrough curves, whereas the Adams–Bohart model could only predict the initial part of the breakthrough curves. Using water with low arsenic concentration, pozzolan demonstrated its effectiveness in arsenic removal below the acceptable level (10 μg/L).