The pollution by heavy metal in the environment, particularly groundwater, constitutes an environmental problem and health in Côte d’Ivoire. Among methods used for removal heavy metals, adsorption by natural absorbent such as a laterite is effective and cheap when compared to other methods. So, this study evaluates the laterite reactor performance for effective removal of heavy metals viz., arsenic (As), nickel (Ni) and lead (Pb) from real-life groundwater. And adsorption of heavy metals was performed with laterite of different particle sizes, viz. coarse grain size of laterite (LRCOG) and laterite granules (LRG). The results obtained showed that the percentages of removal of heavy metal are higher than the size of the laterite. As, Ni and Pb removal are 98.3 ± 0.4%, 99.2 ± 0.2% and 96.1 ± 1.1% respectively in LRCOG effluents. With the laterite in form of granules, percentage removal were of 98.6 ± 0.3% for As that of the Ni is of 99.7 ± 0.2% and 97.9 ± 0.5 % for Pb. The adsorption of heavy metal on the two types of laterite particle size is in the same order of effectiveness: Ni˃As˃Pb.

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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.

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.