Kouassi Dongo

Extreme precipitation has caused catastrophic flooding across West Africa, worsened by climate change. Understanding which rainfall type (deep, stratiform, or shallow convective) drives flooding along the West African coast can improve disaster response. This study combines seven years (2015–2021) of Global Precipitation Measurement (GPM) Dual-frequency Precipitation Radar (DPR) monthly rain-type retrievals with forty-two years (1984–2025) of in situ daily rainfall observations from SODEXAM at Abidjan. GPM DPR data were aggregated into monthly climatological maps to characterize each rain type’s spatial distribution and seasonal cycle, while SODEXAM daily records were analyzed for rainy-day frequency and depth to identify the flood-critical period. All three types of rainfall contribute to the region’s high seasonal totals, but deep convective rainfall dominates and peaks in May and June, contributing on average 60% of total monthly rainfall versus 35% for stratiform and 5% for shallow convective rainfall. The 42-year ground record showed elevated rainy-day frequency and rainfall depth between 29 May and 18 June, defining a flood-critical period. This period coincides with the climatological peak in GPM-derived deep convective rainfall, indicating that deep convective systems are closely associated with the recurrent severe flooding observed in Abidjan from late May to mid-June.

The value of electronic waste as an urban mine has been extensively demonstrated, particularly regarding its rich content in precious metals. However, little is known about the economic feasibility in informal recovery contexts like in Burkina Faso. Previous studies were focused on formal and industrialized systems, overlooking informal dynamics in low-income countries. This study addressed that gap by applying a scenario-based Extended Cost–Benefit Analysis to assess metal recovery pathways in Burkina Faso. Six scenarios were modeled, combining technological selectivity, variations in local collection costs, and policy incentives such as Extended Producer Responsibility and eco-taxes as well as socio-environmental co-benefits. Results showed that e-waste recovery in the informal sector became economically viable when technological, financial, and policy instruments were combined. At a reduced e-waste cost of 5 USD/kg, manual dismantling and bioleaching technologies allowed for net benefits of 6.34 and 6.85 USD/kg, respectively, corresponding to improvements of 136% and 133% compared to baseline losses. Even at 10 USD/kg, both methods remained viable with positive returns and benefit–cost ratios above 1.06. It is impossible to generate net benefits with an e-waste purchase price of 10 USD/kg without EPR or eco-tax mechanisms, unless the price is reduced to 5 USD/kg; this could impose enormous constraints on collection activities. These findings confirmed that no single factor is sufficient to achieve profitability, highlighting the need to integrate supportive policies, technological appropriateness, and environmental co-benefits, a combination that aligns with circular economy principles and is essential to unlock the full potential of e-waste recovery in low-income countries.

Description du sujet: La gestion des déchets est l’un des services publics les plus importants pour les populations urbaines. Cependant, en Afrique subsaharienne, l’accès à un service de collecte demeure un problème majeur, et la Côte d’Ivoire n’est pas en marge de cette situation. En effet, après une décennie de conflit sociopolitique, l’état d’insalubrité des centres urbains secondaires de la Côte d’Ivoire s’est considérablement aggravé. Objectif: L’objectif de cette étude est d’évaluer les systèmes de gestion des déchets solides municipaux de la ville de Tiassalé. Méthodes: L’investigation a d’abord concerné des entretiens, ensuite une enquête géographique et enfin une enquête ménage sur un échantillon de 120 ménages. Résultats. Les résultats ont montré que le service technique municipal était le principal acteur de la gestion des déchets solides municipaux à Tiassalé malgré le fait que cette prérogative ait été retirée aux municipalités en 2007. Au total, 50 sites de dépôts sauvages ont été identifiés. Seulement 33 % des ménages de la ville ont accès à un service de collecte des déchets. L’étude a également montré que la majorité des ménages (67 %) n’était pas satisfait du service de collecte actuel à cause de son irrégularité et son taux de couverture très faible. Conclusion. Ces résultats illustrent clairement l’inefficacité du système de gestion des déchets à Tiassalé comme dans les autres centres urbains secondaires de la Côte-d’Ivoire. L’élaboration d’une nouvelle stratégie de gestion des déchets ainsi qu’un appui financier gouvernemental sont nécessaires pour améliorer l’état de salubrité de ces villes. English title: Evaluation of municipal solid waste management system of the town of Tiassalé in southern Côte d'Ivoire Description of the subject. Waste management is one of the most important public services for urban populations. However, in sub-Saharan Africa, access to a waste collection service remains a major problem, and Côte d'Ivoire is not standing on the sidelines of this situation. Indeed, after a decade of socio-political conflict, sanitation conditions in Côte d'Ivoire's secondary urban centers have worsened considerably. Objective: This study aimed at evaluating municipal solid waste management systems in the town of Tiassalé. Methods: The investigation involved firstly interviews, then a geographical survey and finally a household survey on a sample of 120 households. Results: The results showed that the municipal technical service was the main actor of municipal solid waste management in Tiassalé, even though this prerogative was withdrawn from municipalities in 2007. A total of 50 illegal dumping sites have been identified. Only 33 % of the city's households have access to a waste collection service. More than half of these households (67 %) were not satisfied with the collection service due to its irregularity and low coverage rate. Conclusion: These results clearly illustrate the ineffective waste management system in Tiassalé, as in the other secondary urban centers of Côte d'Ivoire. A new waste management strategy and financial support from the government are needed to improve waste management in these towns.

Lack of appropriate sanitation, with poor hygiene and unsafe water, are sources of the spread of diseases. Ongoing efforts to control neglected tropical diseases, including helminth and intestinal protozoan infections, must be maintained and strengthened with new approaches. The aim of this study was to test the adherence of communities to the Community-Led Total Sanitation (CLTS) approach. The study was conducted in three (3) departments in south- central Côte d'Ivoire. In practice, the process of implementing CLTS involves 5 major steps: i) Mapping of defecation areas, ii) Calculating of human fecal matter quantity and medical costs, iii) Walk of shame, iv) Analysis of contamination pathways, v) Community decision making and latrine construction. Overall, latrine coverage and usage rates have increased considerably in the intervention localities. In particular, out of the 26 localities where the CLTS was applied, 11 reached a latrine coverage rate higher than 80%, 6 of which reached a 100% coverage rate. The results of this work should be used to raise awareness in rural communities about the importance of building and using latrines. Furthermore, CLTS implemented on a large scale can contribute to achieving Goal 3 and 6 of the Sustainable Development Goals (SDGs).

The failure of sewage and drainage systems in SubSaharan African cities is frequent and can be considered as a critical issue, both from an environmental standpoint and in terms of associated maintenance costs. This study analyzes the state of the sanitation systems, the elements behind the failures, the environmental concepts used to classify the problems, and the tools and methodological alternatives for ranking the various management solutions. This research illustrates the causes that contribute to the dysfunctions in the sewage systems of Abidjan as a typical example of sewerage systems management challenges in SubSaharan Africa’s large cities. Poor solid waste and wastewater management practices by residents, e.g., illegal dumping of solid waste into the sewers, unauthorized and defective connections to the network, structural dysfunctions related to the age of the network (cracked, denuded, or broken), urban agriculture in the vicinity of the channels, natural phenomena such as erosion, landslides in the undeveloped parts, and the high concentration of vegetation in the network, wholly contribute to the degradation of the network. A variety of decision support systems for the management of the assets of the urban sewage network were presented. The instruments have been categorized based on their capacity and functionality. The operating concept of each of these tools has been outlined, as well as their respective data needs. In addition, the study analyzes challenges related to the usage of existing decision support systems and provides an outlook on future research requirements in this area. This study offers a detailed analysis of the issues of sanitation management and could serve as a reference for other emerging nations in SubSaharan Africa.

Burkina Faso, like other Sahelian countries, has experienced a profound change in its climatic regime,with the new context characterised by high rainfall variability with an overall downward trend and ashortening of the seasons. The future rainfall pattern anticipates a decrease in the frequency of lowrainfall (0.1 to 5 mm per day), a lengthening of the average duration of dry sequences, and an early endand late start of rainy seasons. The objective of this study was to perform an in-depth analysis of stakeholder perceptions about agricultural water (AgWater) resources sustainability, practices in the context of climate variability and change in Burkina Faso. Interviews were held with institutional actors involved in water resources decision making and initiatives (Government, Research, Non-Governmental Organisations) in the country. In addition, based on four main criteria (climate condition, type of farm and crop, type of AgWater sources, reliability of AgWater), three agricultural sites were investigated using household surveys. The results showed that organisations and farmers in Burkina Faso were aware of climate impacts and had initiated and implemented for many years, diverse options and water control mechanisms for AgWater adaptation. However, there were still gaps in strategies for adapting the water sector to climate threats. Institutional bodies had not got yet attained capacity to sustainably anticipate the effects of climate change on AgWater. There was a lack of mainstreaming hydroclimate services at farm levels, especially for the dry season crops; lack of on-farm flood control mechanisms, absence of a clear gender approach and no standardised monitoring system, Farmers also lacked anticipatory resilience strategies, particularly those who used water sources that were considered as “reliable” then. In general, most of the climate adaptation initiatives implemented lacked synergies, sustainability, and were uncertain about sound water resource management such as moving towards “no regret” and “win-win” options.

Parasitic worms (helminths) are common infections in low- and middle-income countries. For most helminth species, school-aged children are at highest risk of infection and morbidity, such as impaired cognitive and physical development. Preventive chemotherapy is the current mainstay for helminthiases control. Sanitation improvement and hygiene-related education are important complementary strategies, which act by altering children’s behaviour. However, little is known about the effect of improved knowledge on the risk of helminth infection. The aim of this study was to assess the potential influence of knowledge that children acquired at home or in school, without any specific health education intervention, on helminth infections. In May 2014, we conducted a cross-sectional survey in western Côte d’Ivoire. A total of 2498 children, aged 9-12 years, were subjected to three consecutive stool examinations using duplicate Kato-Katz thick smears to determine infections with soil-transmitted helminths and Schistosoma mansoni. Additionally, children were interviewed to assess their knowledge about helminth infections. Four knowledge scores were constructed by factor analysis; one, reflecting general knowledge about helminths and three manifesting helminth species-specific knowledge. The effect of general and specific knowledge on children’s helminth infection status was determined using meta-analysis. Children who scored high in the hookworm-specific knowledge were less likely to be infected with hookworm but no association was found for the other helminth species. Moreover, greater general knowledge was not associated with lower odds of being infected with any helminth species. Most of the children interviewed believed that the effect of preventive chemotherapy is permanent, and hence, re-treatment is not necessary. Specific knowledge about different types of helminths might not suffice to induce behavioural change which in turn reduces infection and reinfection with helminths. Health education interventions should strive to strengthen the perception of risk and to clarify the true benefit of preventive chemotherapy.

The global strategy to control helminthiases (schistosomiasis and soil-transmitted helminthiasis) emphasizes preventive chemotherapy. However, in the absence of access to clean water, improved sanitation, and adequate hygiene, reinfection after treatment can occur rapidly. Integrated approaches might be necessary to sustain the benefits of preventive chemotherapy and make progress toward interruption of helminthiases transmission. The aim of this study was to assess and quantify the effect of an integrated control package that consists of preventive chemotherapy, community-led total sanitation, and health education on soil-transmitted helminthiasis, schistosomiasis, intestinal protozoa infection, and diarrhea in rural Côte d'Ivoire. In a first step, a community health education program was developed that includes an animated cartoon to promote improved hygiene and health targeting school-aged children, coupled with a health education theater for the entire community. In a second step, a cluster randomized trial was implemented in 56 communities of south-central Côte d'Ivoire with 4 intervention arms: (1) preventive chemotherapy; (2) preventive chemotherapy plus community-led total sanitation; (3) preventive chemotherapy plus health education; and (4) all 3 interventions combined. Before implementation of the aforementioned interventions, a baseline parasitologic, anthropometric, and hygiene-related knowledge, attitudes, practices, and beliefs survey was conducted. These surveys were repeated 18 and 39 months after the baseline cross-sectional survey to determine the effect of different interventions on helminth and intestinal protozoa infection, nutritional indicators, and knowledge, attitudes, practices, and beliefs. Monitoring of diarrhea was done over a 24-month period at 2-week intervals, starting right after the baseline survey. Key results from this cluster randomized trial will shed light on the effect of integrated approaches consisting of preventive chemotherapy, community-led total sanitation, and health education against infections with soil-transmitted helminths, schistosomes, an intestinal protozoa and prevention of diarrhea in a rural part of Côte d'Ivoire. The research provided new insights into the acceptability, strengths, and limitations of an integrated community-based control package targeting helminthiases, intestinal protozoa infections, and diarrhea in rural communities of Côte d'Ivoire. In the longer term, the study will allow determining the effect of the integrated control approach on infection patterns with parasitic worms and intestinal protozoa, diarrheal incidence, anthropometric measures, and hygiene-related knowledge, attitudes, practices, and beliefs. International Standard Randomized Controlled Trial Number (ISRCTN): 53102033; http://www.isrctn.com/ISRCTN53102033 (Archived by WebCite at http://www.webcitation.org/6wpnXEiHo). RR1-10.2196/9166.

In-depth analysis of nitrogen flows (NF) using Material Flow Analysis (MFA) was curried out to assess the impact of the current urban sanitation system in the city of Yamoussoukro in Côte d’Ivoire. The aim of the study was to develop resource recovery mitigating option for a sustainable management of the sanitation system. MFA simulations were improved by integrating R.3.0.1 and STAN 2.5 in the research framework. With a context of limited data, NF were efficiently assessed using Monte Carlo simulation in R with 1,000 iterations, based on probability distribution and statistics of input parameters. About 905 tons of nitrogen per year are discharged from the sanitation system including waste water, solid waste and faecal sludge. The discharged nitrogen degrades the urban environment and increases human exposure to health risk. To address sustainable mitigation measures, three resource recovery sanitation technology scenarios were developed. The first scenario integrates lagoons and composting plants while the second and third scenarios include unplanted and planted drying beds respectively together with co-composting. The first scenario allows potential reuse in agriculture, of 89.3% (808.6 tons) of total nitrogen produced per year which would otherwise be discharged to the environment. This scenario was thus found to be the most ecologically relevant and low-cost option. The study highlighted relevant statistical estimations, reduction of time and energy consumption in simulations, MFA potential for environmental risk mitigation and improved agriculture by nutrient recovery. This productive urban waste management option could be helpful for urban planners in developing cities. © 2017 International Formulae Group. All rights reserved. Keywords: Material Flow Analysis; Nitrogen Flows; Urban Waste Management; Monte Carlo simulation, Côte d’Ivoire, Sensitivity analysis

The land use/land cover of the district of Cocody in Abidjan, Côte d’Ivoire, is under substantial pressure associated with ‘fast urbanization. This study conducts a detailed analysis of the impact of the changing land use/land cover in Cocody by assessing inhabitants’ social vulnerability to heat. The approach was based on integrated methods: remote sensing-based analysis of urban land cover helped to analyze the urbanization dynamic, while indicator-based analysis, through the integrated theoretical MOVE framework, helped to define vulnerability and identify indicators. Both methods combined allowed an analysis of the social vulnerability of Cocody inhabitants to extreme heat conditions. The results reveal that Cocody is experiencing rapid land use/land cover change dominated by rapid growth of buildings and a noticeable decrease in the natural environment. Cocody is highly vulnerable to extreme heat conditions, which could be aggravated by its increasing population, with a high percentage of children under five years of age (11.31%). Creating more green spaces is therefore recommended in the more susceptible areas to counter the harmful effects of the changing climate.