Sludge produced in drinking water treatment plants (DWTP) is discharged into environment every day, even they are rich in phosphorus-reactive elements. The objective of this study was to evaluate the removal of phosphorus using sludge from DWTP of the city of Sinematiali (Côte d’Ivoire). The sludge was packaged in granules and put in contact in beaker with synthetic water et effluent from domestic wastewater treatment plant. The results demonstrated that the sludge was rich in aluminum (307.6 ± 0.6 g/kg) and iron (208.7 ± 1.2 g/kg), two phosphorus removal agents. Phosphorus removal was described mainly by adsorption process, which equilibrium was reached after 4 h of contact time at pH 5. Removal of phosphorus from wastewater was around 70% in synthetic wastewater and 42.5% in real wastewater. Removal rate was enhanced when the sludge dosing increased from 10 to 40 g/l, from 42.5 to 87.5%. The adsorption of phosphorus is described by the Langmuir isotherm with qm = 1.72 mg/g and kinetic removal followed pseudo-order 2 model (k2 = 0.023 g/mg.min). Sludge from DWTP of Sinematiali demonstrated good phosphorus removal potential.
The most of groundwater in Katiola area present high relatively proportions of iron. Previous works indicate that over 67% of collected water have iron proportions above the WHO guideline value which is 0.3 mg L-1. If iron and manganese do not pose serious health risks, their presence may indicate that groundwater is of poor quality and may be indicative of an existence of other problems that could cause adverse health effects. Therefore, this study aims to determine the origin of iron in groundwater of the area study and give answers to high iron contents. To achieve this goal, we applied multivariate analysis (CNPA and CAH) on the results of physico chemical analysis and overlay maps of iron distribution with geological map. The results of the ACPN indicate that; solubility of iron and manganese increases in anoxic conditions. The overlay map of iron concentration distribution of with geological map shows that, high iron levels are found in greater proportion in the biotite’s granites; suggesting their origin related to the geology of the area study.
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