This work deals with the physicochemical and microbiological characterization of a hospital wastewater that is directly discharged in water bodies without treatment. Our focus was paid on the teaching hospital of Treichville (Cote d'Ivoire). For the purpose, various physicochemical parameters such as temperature, pH, dissolved oxygen, total dissolved solid, conductivity, nitrate, phosphate, chloride, chemical oxygen demand (COD), biological oxygen demand for five days (BOD 5), salinity, and total suspended solids have been assessed. For the microbiological investigations, the parameters consisting in Pseudomonas aeruginosa, Salmonella and total coliforms have been assessed. From the analysis, it has been found that the wastewaters of the teaching hospital of Treichville are highly loaded in organic pollutants and in pathogens bacteria. The values of nitrate, dissolved oxygen demand, COD, BOD 5 and biological parameters do not respect the international (WHO) values recommended for the water to be discharged in the environment. The ratio COD/BOD 5 has been determined to vary between 1.25 and 2.80. The results showed that the studied wastewater is a domestic type wastewater composed either by mostly biodegradable pollutants or a mixture of biodegradable and non-biodegradable organic pollutants. These wastewaters constitute therefore a risk for the populations since they are discharged in water bodies without any treatment and used by communities.

<p>In the present study, adsorption experiments were carried out to investigate the removal of rhodamine B from an aqueous solution using chemically activated carbon from corn cobs, a cheaper adsorbent. The characteristics of carbon were determined using X-ray diffraction, SEM, iodine number, pHpzc, and the Boehm titration method. The results show that the prepared activated carbon is amorphous, microporous, and generally acidic on the surface. The kinetic study of the adsorption of rhodamine B on this carbon was carried out, and the rate of sorption was found to conform to pseudo-second-order kinetics with 80 min as equilibrium time. The equilibrium adsorption revealed that the experimental data fitted better to the Langmuir isotherm model for removing rhodamine B. The interaction rhodamine B-activated carbon is mainly chemisorption type. The optimal conditions of rhodamine B removal onto the carbon of this study are mass of carbon = 0.3 g and pH = 3.15. The maximum monolayer adsorption capacity for rhodamine B removal was found to be 5.92 mg.g^-1. This study has shown that the prepared activated carbon makes it possible to effectively clean up wastewater contaminated by rhodamine B with a removal efficiency of up to 99.60% for 300 mg of AC in 25 mL of the rhodamine B solution (5 mg.L^-1).</p>

This work aimed to contribute to the mechanism electrochemical oxidation study of organic compounds on DSA electrodes. To do this, IrO₂ and RuO₂ electrodes were prepared thermally at 40°C on Titanium substrate. The prepared electrodes were characterized using voltammetric and SEM techniques. The electrochemical measurements in acid media made it possible to show the presence of IrO₂ and RuO₂ on the surface of the electrode. These electrodes have identical electrocatalytic behaviors both for oxygen evolution and chlorine evolution. The prepared electrodes make it possible to oxidize the organic compounds in an acid media in the absence or in the presence of Cl^-. In acidic electrolytes, water molecules produce hydroxyl radicals that contribute to the higher oxides (RuO₃ or IrO₃) formation. The higher oxides obtained produce O₂ and regenerate the active sites of our electrodes. In the electrolytes containing chlorides, higher oxides fix them (IrO₃(Cl) or RuO₃(Cl)) in competition with the production of O₂. Then IrO₃(Cl) or RuO₃(Cl) reacts with Cl^- to produce Cl₂ and regenerate the adsorbed hydroxyl radicals. The higher oxides also react as a mediator in HCOOH oxidation in competition with O₂ evolvement. In the electrolytes containing HCOOH and Cl^-, the organic pollutant's oxidation occurs indirectly via the hypochlorite ions produced in the solution and on the electrodes. This study showed that the produced OH· and Cl₂ in situ are involved in the oxidation of HCOOH

Biological treatment, due to its low installation cost, is widely used for wastewater treatment. However, this treatment remains ineffective for the oxidation of so-called emerging molecules. To solve this environmental problem, advanced oxidation processes (AOPs) combine with Biological treatment for rapid, efficient and cost-effective purification of wastewater. This combination used in this work, allowed a total mineralization of a real wastewater solution from the teaching hospital of Treichville named CHU of Treichville in Abidjan (CHUT), both in terms of organic and microbiological pollutants. Real wastewater from the CHUT underwent a Biological treatment for 28 days via the Zahn-Wellens methods which made it possible to have a reduction rate of the chemical oxygen demand of more than 90% of biologically active organic pollutants. The biologically treated wastewater was doped with ceftriaxone (CTX) to simulate a situation of wastewater containing a recalcitrant compound after Biological treatment. Subsequently, the doped solution underwent treatment with different AOPs (UV / H2O2, Fe2+ / H2O2 and UV / Fe2+ / H2O2). This combination resulted in a COD reduction rate of over to be higher 98% and total inactivation of microbiological germs.

The platinum anode modified by metal oxides electrodes degrades Abidjan wastewater which contains a high concentration of Cl-. During this degradation process, the organic polluants are oxidized, O2 and Cl2 are produced. The purpose of this study is to contribute to the understanding of these reaction mechanisms by studying the kinetics of O2 and Cl2 evolution at neutral pH on Pt. The study was performed by interpreting the voltammograms and Tafel slopes obtained. The voltammetric measurements were carried out using an Autolab Potentiostat from ECHOCHEMIE (PGSTAT 20) connected by interface to a computer. Pt electrode was prepared on titanium (Ti) substrate by thermal decomposition techniques at 400°C. The characterization of the surface of the prepared electrode by scanning electron microscopy and X-ray photoelectron spectrometry showed the presence of platinum on its surface. The results obtained show that the OH· are adsorbed on the active sites of Pt. Then they react to form PtO. Then by reaction between the surface oxygen and PtO, O2 is produced and the active sites are regenerated. In the presence of low Cl- concentration, there is a competition between the Cl2 and O2 evolution reactions. However, Cl2 only is produced for high Cl- concentrations. The kinetics of the evolution reaction of chlorine increases with the concentration of Cl- and remains constant for concentrations greater than 0.5 M. This study also showed that the chlorine reduction reaction produced in solution is a diffusion-controlled reaction for low scan rates.