Contribution à l’état des lieux de déchets solides ménagers dans la ville D’Uvira, Sud-Kivu, République Démocratique du Congo

L’explosion démographique, l’accroissement des activités urbaines, l’insuffisance des ressources financières des pouvoirs publics au niveau local et l’absence de réelles politiques environnementales sont parmi les facteurs qui expliquent la présence des déchets le long des grandes artères des villes de l’Afrique subsaharienne. Ce travail a porté sur la contribution à l’état de lieux des déchets solides ménagers dans la ville d’Uvira. L’échantillonnage était systématique, basé sur les activités socioprofessionnelles de ménages en vue d’atteindre toutes les couches de la population notamment, les agents de la fonction publique, les commerçants, les agriculteurs et les pêcheurs, les services de recette et paraétatique, et enfin autres (chômeurs, motards, débardeurs, taximans…). La production journalière d’un habitant d’Uvira est évaluée à 0,45 kg/j.hab, le tri systématique de déchets présente 60% de fermentescibles, 13% de tissus, 2% de mitrailles, 11% de papierscartons et 14% de sachets-plastique. La production des déchets solides varie selon l’appartenance socioprofessionnelle de ménages et d’un quartier à l’autre. L’objectif de ce travail est d’utiliser les résultats de quantification et caractérisation de ces déchets solides ménagers pour permettre de faire dans une prochaine étude, le choix de voies de traitement les mieux adaptées.Mots clés : Déchets solides ménagers, Uvira, menace écosystémique

Predicting quality and quantity of water used by urban households based on tap water service

AbstractDespite significant progress in improving access to safe water globally, inadequate access remains a major public health concern in low- and middle-income countries. We collected data on the bacterial quality of stored drinking water and the quantity of water used domestically from 416 households in Uvira, Democratic Republic of the Congo. An indicator of tap water availability was constructed using invoices from 3685 georeferenced piped water connections. We examined how well this indicator predicts the probability that a household’s stored drinking water is contaminated with Escherichia coli, and the total amount of water used at home daily, accounting for distance from alternative surface water sources. Probability of drinking water contamination is predicted with good discrimination overall, and very good discrimination for poorer households. More than 80% of the households are predicted to store contaminated drinking water in areas closest to the rivers and with the worst tap water service, where river water is also the most likely reported source of drinking water. A model including household composition predicts nearly two-thirds of the variability in the reported quantity of water used daily at home. Households located near surface water and with a poor tap water service indicator are more likely to use water directly at the source. Our results provide valuable information that supports an ongoing large-scale investment in water supply infrastructure in Uvira designed to reduce the high burden of cholera and other diarrhoeal diseases. This approach may be useful in other urban settings with limited water supply access.</jats:p

The impact of improved water supply on cholera and diarrhoeal diseases in Uvira, Democratic Republic of the Congo: a protocol for a pragmatic stepped-wedge cluster randomised trial and economic evaluation.

INTRODUCTION: Diarrhoeal disease remains a leading cause of mortality and morbidity worldwide. Cholera alone is estimated to cause 95,000 deaths per year, most of which occur in endemic settings with inadequate water access. Whilst a global strategy to eliminate cholera by 2030 calls for investment in improved drinking water services, there is limited rigorous evidence for the impact of improved water supply on endemic cholera transmission in low-income urban settings. Our protocol is designed to deliver a pragmatic health impact evaluation of a large-scale water supply intervention in Uvira (Democratic Republic of the Congo), a cholera transmission hotspot. METHODS/DESIGN: A stepped-wedge cluster randomised trial (SW-CRT) was designed to evaluate the impact of a large-scale drinking water supply intervention on cholera incidence among the 280,000 inhabitants of Uvira. The city was divided into 16 clusters, where new community and household taps will be installed following a randomised sequence over a transition period of up to 8 weeks in each cluster. The primary trial outcomes are the monthly incidence of "confirmed" cholera cases (patients testing positive by rapid detection kit) and of "suspected" cholera cases (patients admitted to the cholera treatment centre). Concurrent process and economic evaluations will provide further information on the context, costs, and efficiency of the intervention. DISCUSSION: In this protocol, we describe a pragmatic approach to conducting rigorous research to assess the impacts of a complex water supply intervention on severe diarrhoeal disease and cholera in an unstable, low-resource setting representative of cholera-affected areas. In particular, we discuss a series of pre-identified risks and linked mitigation strategies as well as the value of combining different data collection methods and preparation of multiple analysis scenarios to account for possible deviations from the protocol. The study described here has the potential to provide robust evidence to support more effective cholera control in challenging, high-burden settings. TRIAL REGISTRATION: This trial is registered on clinicaltrials.gov ( NCT02928341 , 10th October 2016) and has received ethics approval from the London School of Hygiene and Tropical Medicine (8913, 10603) and from the Ethics Committee from the School of Public Health, University of Kinshasa, Democratic Republic of the Congo (ESP/CE/088/2015)

Complete mitochondrial genomes and updated divergence time of the two freshwater clupeids endemic to Lake Tanganyika (Africa) suggest intralacustrine speciation

acceptedVersio

Toxicological risk of urban effluents discharged into the North-Western Coast in Lake Tanganyika (Democratic Republic of Congo) and their treatment by pressure-driven membrane filtration

Water scarcity is one of the problems caused by global industrialization. In developing countries, population increase, rural exodus and environmental degradation are major threats to humanity. Inadequate wastewater treatment is a major concern, as it contributes greatly to the destruction of water resources when discharged into the environment. In the Democratic Republic of Congo, sanitation is not sufficiently developed. The remarkable lack of qualified human resources for the analysis and monitoring of environmental quality, technical and/or financial means does not allow for the implementation of coherent programs adapted to the realities and challenges facing the country. Much of the work carried out by researchers in the Democratic Republic of Congo is limited to the evaluation and quantification of pollution, concluding that population should not consume fish or water from polluted sites. However, there is an expression commonly used in low-income countries, which says "a hungry stomach has no ears". With this in mind, this study focuses on the application of emerging technology based on reverse osmosis and nanofiltration to treat urban effluent discharged into the north-western coast of Lake Tanganyika (Democratic Republic of Congo). Two main global objectives were considered in this study, namely: i) the determination of pollution and toxicological risk of pollutants on the northwestern slope of Lake Tanganyika, and ii) the development of a treatment method of domestic and industrial wastewater by commercial membranes, including the preparation of a low-cost membrane to remove pollutants. The determination of pollution was based on chemical analysis of organic and inorganic micropollutants, and the toxicity test by bio-testing was experimented in aquariums at the laboratory of the Hydrobiology Research Center in Uvira. The results show that the wastewater is polluted by highly toxic inorganic and organic compounds. The sources of pollution came from the reference hospital of Uvira, the penitential center of Uvira, the households, the artisanal food-processing industries, the degradation of non-recycled household waste and the physical alteration of the sedimentary rocks of the Precambrian period that form the substrates. The real waters sampled in Uvira were filtered on 200 µm filter paper to retain large particles that can affect membrane fouling and clogging. These real waters had not undergone any other chemical pre-treatment. After the physical pretreatment, they were filtered on commercial reverse osmosis membranes of polyamide type and NF90, NF270 to remove inorganic micropollutants. The synthetic waters were prepared in the laboratory with the specific ions under study at known concentrations. Those waters were filtered through commercial reverse osmosis membranes, as well as nanofiltration membranes (NF90 and NF270) to remove metal ions. The experimentation of commercial membranes allowed to evaluate its performance. Next, a membrane containing chitosan and the metallic organic framework ZIF-8 (i.e., CS/ZIF-8 mixed matrix membrane) was prepared at the laboratory and characterized by XRD, SEM, FTIR, angle contact, and tested in the reverse osmotic unit using the synthetic waters at different concentrations. The results obtained show that the retention of ions by the polyamide reverse osmosis membranes is excellent, although the permeate flux is low. The retention with nanofiltration membranes depends on the feed concentration and ionic interactions at the membrane surface. Regarding the self-made CS/ZIF-8 mixed matrix membrane, it shows better retention performance for Cr3+, Pb2+, Cd2+ and Ni2+ ions in a concentrated feed solution and high-water permeability at low operating pressure. In addition, industrial scaling-up of the CS/ZIF-8 membrane is more attractive, as the manufacturing cost is low and the permeate flux high. The economic feasibility analysis shows that the investment cost is high, but energy consumption is low.(FSA - Sciences de l'ingénieur) -- UCL, 202

Modèle thermogravimétrique d’évaluation des rendements de pyrolyse et de gazéification de la fraction fermentescible des déchets ménagers à Bujumbura

Le présent travail, a procédé à la caractérisation et la quantification des constituants des déchets de biomasse déversés à la décharge de Mubone en procédant un à tri manuel.Il a été montré que la fraction fermentescible varie de 68 à 72%. En tenant compte des analyses immédiates et élémentaires de chaque fraction, les bilans massiques et énergétiques des procédés de thermolyse et de gazéification des déchets sont évalués grâce à l’utilisation d’un « outil prédictif Excel » développé à l’Université Libre de Bruxelles et basé sur l’hypothèse d’additivité du comportement de chaque composant du déchet durant la décomposition thermique.Les résultats obtenus en utilisant cet outil pour le mélange de déchets fermentescible séchés à 35% d’humidité et dont les différentes fractions sont quantifiées dans l’étude, permet de d’obtenir des combustibles de substitution dont les énergies récupérables sont comprises entre 13.5 et 15.7GJ par tonne déchets séchés pyrolysés et entre17,5 à 22,5GJ par tonne déchets séchés gazéifiés.Le PCI des fractions fermentescibles des déchets bruts ont été évaluées par calorimétrie. Ces fractions fournissent un pouvoir calorifique inférieur compris entre 3,9 MJ/kg et 5,9MJ/kg. L’utilisation de l’outil comme modèle prédictif simple, il est montré que les voies de traitement thermiques de pyrolyse et gazéification peuvent être envisagées afin de permettre de fournir de l’énergie aux ménages de Bujumbura en évitant aussi la déforestation.Il est important de noter que le séchage dans les pays chauds tels que le Burundi peut être effectué sans dépense d’énergie mais en utilisant l’énergie solaire.info:eu-repo/semantics/publishe

Evaluation of commercial reverse osmosis and nanofiltration membranes for the removal of heavy metals in water sources from the Democratic Republic of Congo

This study evaluates the performance of commercial reverse osmosis (RO) and nanofiltration (NF) membranes for the removal of metal ions from synthetic industrial wastewater and household wastewater carried from the north-west of Tanganyika Lake in the city of Uvira, in the east of the Democratic Republic of Congo. RO membranes showed higher rejection of metal ions from the synthetic samples prepared in the laboratory as well as from the raw water collected from the surroundings of the Tanganyika Lake, reaching rejections higher than 98% for Cr, Pb, Cd, As, Ni, and Sb ions in the synthetic industrial solutions, and 99.2, 98.8, 98.6, 99.2, 98.4 and 98.8% respectively in real samples. The ions concentrations decreased in the permeates of RO, NF90 and NF270 respectively from 0.15 to 1.02 mg/L; 0.33 to 22 mg/L and 0.11 to 22 mg/L. Regarding the NF membranes, their rejection was lower: 98.2, 76.9, 92.3, 52.5, 97.8, and 64.1% for Cr, Pb, Cd, As, Ni, and Sb ions, respectively, but the flux was 329 to 375 L/hm2 higher compared to RO membranes was 98 to 132 L/hm2. The studied membranes are thus a feasible solution to remove the studied metals from real wastewater sources at low concentration since they meet the water quality standards recommended by the World Health Organization. The reverse osmosis membrane is best suited for high concentration synthetic waters

Evaluation of commercial ro and nf membranes, used for the release of heavy metals in wastewater

Inverse omosis elimination rate is high compared to nanofiltration. The concentration of certain metals in the the permeates of domestic wastewater are lower to the WHO standard, while in the industrial water permeates, it remains above the WHO standard, hence the need to prepare a low cost membrane to remove these metals in the permeate according to the WHO standard

Qualitative and quantitative analysis of the pollutant load of effluents discharged Northwestern of Lake Tanganyika, in the Democratic Republic of Congo

The qualitative and quantitative analysis of pollutant loads from effluents discharged into Lake Tanganyika has been studied, with a view to evaluate remediation strategies. The discharge of effluents into Lake Tanganyika calls for concern as it poses serious threats to the biological wealth of the lake. Physico-chemical and microbiological parameters were evaluated for pollution from the effluent source to Lake Tanganyika (discharged point) using standard procedures. Results revealed significant pollution of the lake from prisons, the general hospital of Uvira and household channels. The prison of Uvira was the highest emitter of organic loads with a 42% chemical oxygen demand (COD), followed by the general hospital (30%) and finally households (28%). The absence of faecal coliforms, Escherichia coli and Salmonella sp. could be explained by the high concentration of chloride (varied from 1174 to 1388 mg/L) in this wastewater. The identification of latrines near the said collector reveals that 64% of septic tanks are connected directly or indirectly to the collector and 36% of indigenous latrines. The population is called upon to carry out individual sanitation, by building septic tanks that meets established standards and local authority’s requirement to assist in establishing a waste station which can mitigate the problem

Determination of the Toxicological Risk of Urban Waste from the City of Uvira Dumped into the North-Western Coast in Lake Tanganyika (Democratic Republic of Congo)

This study focuses on determining the toxicological risks of urban waste from the city of Uvira, discharged into Lake Tanganyika, on the surrounding population. Volatile organic compounds were measured in a variety of solid waste matrices, including inorganic micropollutants in wastewater and fish. The concentrations of Hg and Pb in the lake were found to be 1.21 and 1.42 μg/L respectively and between 0.83 to 18.36 μg/L of Hg and 8.25 to 670 μg/L of Pb, at the collector outlet. The presence of trace metallic elements, such as Cr, Co, Ni, Cu, Zn, As, Sb, Hg and Pb, were detected at high concentrations compared to the WHO standard. An ecotoxicology experiment herein on wastewater samples showed lethal pollutant concentrations of the order of 0.0055 mL/mL which killed at least 50% of fish (LC50), confirming the toxicity of the wastewater. These potentially harmful effluents also contain volatile organic compounds originating in high concentration from the pharmaceutical discharges of the general Uvira hospital, in particular: toluene, ethylbenzene, m-xylene / p-xylene, o-xylene and chloroform in higher concentrations compared to the norm. Other components such as benzene, bromodichloroethane and 1,1-dichloroethane were found to be present, but at a concentration below 0.05 ppb. A variety of trace organics can be suspected to be present as well