Characterization of the Leachate from the Municipal Landfill of Akouédo (Abidjan, Côte d´Ivoire)

Municipal solid waste in developing countries especially in Africa are commonly managed by discharging in uncontrolled landfill. This leads to the generation of huge amounts of leachate that are rejected in the nature without any treatment. This study consisted in characterizing the leachate from the Landfill of Akouédo in the District of Abidjan (Côte d’Ivoire) despite the completion of filling operations in 2019. The physico-chemical composition of raw leachate suggested a stabilized landfill, with alkaline pH (i.e. ~ 8.85±0.03). However, the concentrations of nutrients and organics such as NH4+ (212.5±0.31 mg.L-1), NO-2 (257.5±0.42 mg.L-1), NO-3 (301.85±0.16 mg.L-1), BOD5 (1015±0.12 mg O2 L-1) et COD (9640±0.4 mg O2 L-1) obtained in Landfill of Akouédo were slightly weak, compared to the FEPA’s standard (1991). This could confirm the stabilization of the leachate, with a BOD5 / COD ratio of around 0.1 ± 0.05. In addition, most of the metallic trace element contents (i.e. Iron, Copper, Nickel, Zinc and Lead) were below FEPA’s standard (1991). To further investigate, humic acid (HA), fulvic acid (FA) and humin were extracted from the humic substance of this leachate. Thus, about 91 % and 9 % were obtained for humic acid and fulvic acid + humin, respectively. For better understanding, synthetic humic acid (SHA) was used as the reference material. The DRIFT analysis helped determine some difference between the LHAs of the leachate and SHA. However, the characteristics of the functional groups of the LHA and SHA molecules were essentially similar. The data on the characteristics of the HS shown in the results of the landfill leachate can be used in several related research areas, such as the optimization of leachate treatment processes and the remediation of groundwater contaminated with leachate. Keywords: Municipal solid waste, Landfill, Leachate, humic substance, humic and fulvic acid. DOI: 10.7176/JEES/10-4-03 Publication date: April 30th 2020

Assessment of the Potential for Greenhouse Gas Emission Mitigation by the Methanization of Slaughterhouse Waste in the District of Abidjan (Côte d'Ivoire)

Abattoirs are source of huge amounts of waste that contribute to global greenhouse gas (GHG) emissions and thus, to the global warming and climate change. Treating these was with biodigester technology could be a suitable alternative to GHG emission mitigation. The objective of this study is to evaluate the potential for GHG emission mitigation by a biodigester to be installed at the abattoir of Port-Bouët in the District of Abidjan as a pilot project. More specifically, it aims to: (i) estimate the daily biogas production from 2013 to 2018 according to the mathematical methods of Hashimoto, Gwogon, and Amahrouch, and an empirical method, (ii) evaluate the environmental benefits of the biodigester by estimating the avoided GHG emissions according to the methods mentioned above.The mathematical methods used are those of Hashimoto, Gwogon and Amahrouch. In addition, the empirical method was also used. The results showed that regardless of the method, the amount of biogas increased from 2013 to 2017 and decreased in 2018. The highest daily biogas productions are obtained in 2017 for all methods. Thus, the biogas volumes are 564.50 m3 in a biodigester of 2792.64 m3 according to the Hashimoto method, 724.15 m3 for the biodigester of 2228.14 m3 with the Gwogon method and 557.03 m3 for digesters of volumes 2785.17 m3 calculated with the Amahrouch method. According to the empirical method, the maximum volume of biogas is 631.31 m3. Regarding the amount of CO2 avoided per kilogram of dung, the values ranged from 41579.88 to 71561.17 kg CO2e for the Gwogon method, 41643.46 to 71670.58 kg CO2e for the empirical method, 41689.19 to 71749.30 kg CO2e for the Hashimoto method, and 41694.30 to 71758.10 kg CO2e for the Amahrouch method. These results show a great environmental and economic potential of the installation of a biodigester for the treatment of the waste of the slaughterhouse of Port-Bouët. The choice of the anaerobic digestion process was a continuous mixed biodigester where the substrate is introduced daily with liquid

Assessment of the Potential for Greenhouse Gas Emission Mitigation by the Methanization of Slaughterhouse Waste in the District of Abidjan (Côte d'Ivoire)

Abattoirs are a source of huge waste that contributes to global greenhouse gas (GHG) emissions and, thus, to global warming and climate change. This study aimed to evaluate the GHG emission mitigation potential of a biodigester to be installed at the abattoir of Port-Bouët in the District of Abidjan. Mathematical methods developed by Hashimoto, Gwogon, and Amahrouch and an empirical method were used to assess this mitigation potential. The results showed that regardless of the methods, biogas volumes increased from 2013 to 2017 and decreased in 2018. The highest daily biogas production was obtained in 2017 for all the methods. According to Hashimoto's method, the biogas volume was 564.50 m3 in a biodigester of 2792.64 m3. Gwogon's method led to a biogas volume of 724.15 m3 for a 2228.14 m3 biodigester. The calculated volume of biogas with the Amahrouch method was 557.03 m3 for a 2785.17 m3 biodigester. The empirical method showed a maximum biogas volume of 631.31 m3. The amount of CO2 avoided per kilogram of dung ranged from 41579.88 to 71561.17 kg CO2e, 41643.46 to 71670.58 kg CO2e, 41689.19 to 71749.30 kg CO2e for Gwogon, empirical and Hashimoto methods, respectively. The values ranged from 41694.30 to 71758.10 kg CO2e for the Amahrouch method. These results show a biodigester's tremendous environmental and economic potential for treating the waste of the slaughterhouse of Port-Bouët

Practice of diagnostic hysteroscopy after myomectomy in the prevention of intrauterine adhesions: experience of Ouakam military hospital (Dakar, Senegal)

Background: Surgical treatment of myomas may be the cause of some complications, including intrauterine adhesions. The objective of the study was to evaluate the incidence of intrauterine adhesions in patients who underwent myomectomy by laparotomy or hysteroscopic resection.Methods: We carried out a prospective single center study from August 1st 2016 to May 31st 2017 in the gynaecological and obstetrical department of Ouakam the Military Hospital (Senegal). We included patients who underwent myomectomy by laparotomy with opening of the uterine cavity or myomectomy by hysteroscopy. A diagnostic hysteroscopy was performed to search post-operative intrauterine adhesions. For each patient, we studied the socio-demographic aspects, the surgical approach, the delay of diagnostic hysteroscopy, the appearance of uterine cavity and the tolerance of hysteroscopy.Results: 54 patients underwent the diagnostic hysteroscopy. The mean age was 36 years old. The main indication of myomectomy was menorrhagia. 37 patients underwent myomectomy by laparotomy and 17 by hysteroscopy. Each case was followed by a post-operative diagnostic hysteroscopy with a mean delay time of 58 days. We found post-operative intrauterine adhesions in 7 patients (5 in the laparotomy group and 2 in hysteroscopy group).Conclusions: Early diagnostic hysteroscopy after myomectomy should be done in our context to reduce post-operative intrauterine adhesions and preserve the patient’s fertility

Analyse De L’évolution Saisonnière Des Matières Oxydables Dans Le Secteur Oriental De La Lagune Ebrié (Côte d’Ivoire)

Faced with the extension of the cities of Grand-Bassam and Abidjan along the Ebrié lagoon and the lack of data on the oxidizable content in the eastern sector of the Ebrié lagoon, this study was initiated. It aims to determine the levels of oxidizable materials in the eastern sector of the Ebrié lagoon. PH, temperature, salinity and dissolved oxygen were determined in situ at thirtyone (31) stations during the dry season and the rainy season. On these same stations, water samples were also taken per season to determine the content of oxidizable matter according to the methods in force. The statistical treatment consisted in knowing the links between the hydrological parameters. The average values of the parameters in the rainy season and in the dry season are 5,98 and 7,28 respectively for the pH, 27,59 °C and 29,6 °C for the temperature, 5,01 and 19,48 for salinity, 6.14 mg/L and 3.78 mg/L for dissolved oxygen, 0.24 mg/L and 0.38 mg/L for ammonium, 0.089 mg/L and 0.036 mg/L for nitrite, 8.18 mg/L and 0.23 mg/L for nitrate, 1.57 mg/L and 1.78 mg/L for orthophosphate, 76.06 mg/L and 56.81 mg/L for COD and 40.23 mg/L and 34.16 mg/L for BOD5. The evolution of oxidizable matter depends on the entry of continental, oceanic and precipitation waters into the lagoon. The high levels of oxidizable materials are observed in large part in the berries. Good positive correlations are observed between COD and DBO5 and between salinity and nitrite. Temperature and salinity have a good negative correlation. Lagoon waters receive more oxidizable materials in highly urbanized areas than in areas with little or no urbanization

Structures, Deformation Mechanisms and Tectonic Phases, Recorded in Paleoproterozoic Granitoids of West African Craton, Southern Part: Example of Kan’s Complex (Central of Côte d’Ivoire)

The granito-gneissic complex of Kan is located in the central part of the Paleoproterozoic domain of Côte d’Ivoire. It consists essentially of migmatitic and mylonitic gneisses with basic intrusions and xenoliths. This Proterozoic domain belongs to the Man Leo shield, southern part of West African craton (WAC). The present study, essentially based on a structural analysis at outcrop scale, aims to identify deformation mechanisms and tectonic phasesrecorded in the granito-gneissic complex of Kan. Deformation mechanisms include: (1) flattening, (2) constriction, (3) simple shear (4), rotation (5), brittle shear, and (6) extension. The Kan complex deformation occurred during four major tectonic phases named D1, D2, D3 and D4. D1 corresponds to WNW-ESE compression. It led to the formation of NS to NNE-SSW foliation, of stretching lineation, and of folds with sub-horizontal axes. It is accompanied by N170° and N10° sinistral shear zones, which constitute globally a NS major transcurrent shear zone in the central part of Côte d’Ivoire. D1 is also marked by N90° dextral shear zones. Tectonic phase D2 is associated with EW compression. It is marked by N50° dextral and N110° sinistral transcurents shear zones. D3 corresponds to NNE-SSW compressive phase and is responsible of N110° crenulation cleavage formation. (D4) constitutes a brittle deformation phase. It correspondsto posteburnean deformation in the Proterozoic crust of Côte d'Ivoire. Generally, these deformation phases are similar to D2 and D3 reported in the Man-Leo shield and that are part of regional collisional phase referred to as Eburnean orogeny in the WAC