Experimentation on bone char-based treatment for fluoride removal from drinking water in Senegal

In several areas of Senegal fluoride concentration in drinking water exceeds World Health Organization (WHO) guide value. A safe, efficient, simple and low cost defluoridation technique needs to be developed in order to prevent the occurrence of fluorosis. This paper describes a laboratory and pilot experimentation carried out using animal bone char as adsorbent material for fluoride removal. Possible influencing parameters, such as specific ions in Senegalese drinking water, were investigated and the best process conditions were defined for the application in Senegal

Research experiences on the reuse of industrial waste for concrete production

The aim of this study was to assess the feasibility of concrete production using different kinds of industrial wastes as “recycled aggregate”. The wastes studied in this work were: fly ashes and slags from Electric Arc Furnace (EAF) steel plant; foundry sands produced from foundry dies; slags from lead processing; Waelz slags; solid residues from municipal solid waste incineration (MSWI) plant (with mass-burning kiln and fluidized bed reactor); sludge from industrial wastewater treatment plants. Good compressive strength (similar to natural concrete) was achieved after 28 days of curing by concrete mixtures obtained with the partial replacement (from 7% to 40% by weight) of natural aggregates with slags from lead processing, foundry sands, Waelz slags and bottom ashes from MSW incineration. The worst mechanical and leaching behaviours were shown by concrete samples containing EAF fly ashes and sludge from industrial wastewater treatment. For the residues with the best performance, concrete products (kerbs and flat tiles) were casted. Their mechanical and leaching characterization has shown that the reuse of these residues for concrete product is feasible

Sustainability of Water Safety Plans Developed in Sub-Saharan Africa

In developing countries, the drinking water supply is still an open issue. In sub-Saharan Africa, only 68% of the population has access to improved sources of drinking water. Moreover, some regions are affected by geogenic contaminants (e.g., fluoride and arsenic) and the lack of access to sanitation facilities and hygiene practices causes high microbiological contamination of drinking water in the supply chain. The Water Safety Plan (WSP) approach introduced by the World Health Organisation (WHO) in 2004 is now under development in several developing countries in order to face up to these issues. The WSP approach was elaborated within two cooperation projects implemented in rural areas of Burkina Faso and Senegal by two Italian NGOs (Non-Governmental Organisations). In order to evaluate its sustainability, a questionnaire based on five different sustainability elements and a cost and time consumption evaluation were carried out and applied in both the case studies. Results demonstrated that the questionnaire can provide a useful and interesting overview regarding the sustainability of the WSP; however, further surveys in the field are recommended for gathering more information. Time and costs related to the WSP elaboration, implementation, and management were demonstrated not to be negligible and above all strongly dependent on water quality and the water supply system complexity

Planning approaches for sanitation systems in peri-urban areas: a case study from Tanzania

The planning and improvement of sanitation systems represents a critical problem for low-income countries, in particular in rapid growing peri-urban areas. This paper illustrates the assessment of the Community-Led Urban Environmental Sanitation (CLUES) and the Sanitation Safety Planning (SSP) approaches, tested for the design of an improved sanitation system in peri-urban areas of Iringa Municipality, in Tanzania. The application in field of the two approaches permitted to evidence and analyse their strengths and weaknesses, and possibilities to increase their potentials with an integrated use. The experience, applied to a case study, aims to be an example of application for practitioners dealing with sanitation planning in context showing similar characteristics

Impacts de la pollution du lac dans la zone du Technopole de Pikine sur le risque de dispariton des espèces aquatiques

Notre travail a pour but d’étudier les impacts de la pollution du lac dans la zone du Technopole sur le risque de dispariton des espèces aquatiques. Les résultats de cette étude ont montré que certaines zones du lac ne satisfaient pas aux directives internationales pour l’aquaculture. Ainsi, les zones sud et nord proches des environnements respectifs de la station d’épuration et du canal provenant de Dalifort représentent les zones les plus polluées du lac. C’est pourquoi dans la partie sud du lac, il n’existe pas de poissons à pécher ni d’autres animaux aquatiques. En effet, la concentration en DCO est de 1789 mg/L dans la partie nord du lac et celle de la MES est de 85,9 mg/L, donc très élevées, pourraient diminuer la valeur de l’oxygène dissous sans compter l’eutrophisation due à la présence excessive des nitrates soit 67,58 mg/L en moyenne alors qu’elle ne devrait dépasser 10 mg/L. Or, associés aux phosphates, les nitrates favorisent aussi la croissance parfois exagérée de la flore aquatique, pouvant ainsi entraîner une eutrophisation des fleuves et des lacs. En outre, la valeur mesurée de la salinité est très élevée au niveau du lac avec une valeur moyenne de 21g/L, ce qui perturberait l'écosystème et provoquerait la mort d'une grande variété des espèces aquatiques, animales et végétales. Par conséquent, la sédimentation des solides en suspension dans des clarificateurs ou des bassins de décantation ; le traitement biologique, le plus souvent aérobie, pour réduire la quantité de matière organique soluble (DBO); la chloration des effluents si une décontamination s’avère nécessaire et l’élimination des nutriments biologiques pour réduire les quantités d’azote et de phosphore devraient être effectué pour les risques de disparirion des espèces aquatiques dans cette zone du Technopole

Etude De La Qualité Des Eaux Souterraines Utilisées Pour L’irrigation Et Eventuellement Pour La Boisson Dans La Zone Du Technopole De Pikine (Sénégal)

Résumé— Le but de notre étude est l’évaluation de la qualité des eaux souterraines dans la zone du Technopole pour l’irrigation et éventuellement la boisson afin de diminuer les inondations très fréquentes dans cette localité. Ainsi, la qualité des eaux de la nappe du Technopole est assez bonne pour l’irrigation mais très mauvaises pour la consommation humaine. A l’exception de la conductivité (en moyenne 4400 μS/cm  > 3000 μS/cm valeur guide de l’OMS) et du phosphore total (en moyenne 12,75 mg/L > 10 mg/L valeur guide de l’OMS), tous les autres paramètres des eaux souterraines respectent les valeurs limites de l’OMS pour l’irrigation. Par contre, concernant les paramètres de potabilité mesurés, il n y a que les nitrates qui respectent la limite qui est de 50 mg/L dans certains points avec une moyenne de 46,4 mg/L. En effet, nous avons des milliers de U/100 mL d’Escherichia coli alors qu’il devrait être absent dans les eaux destinées à la boisson. Par ailleurs, nous avons aussi des concentrations de TDS très élevées dans l’aquifière du Technopole avec une moyenne de 3200 mg/L alors qu’elle est généralement considérée comme bonne si c’est inférieur à environ 600 mg/L. Cette pollution est directement liée aux rejets des eaux usées de la satation d’épuration (STEP) et aux activités agricoles mais également entretenue par une mauvaise gestion des eaux usées dans la zone. Par conséquent, la non utilisation de l’eau de la nappe du Technopole, réduit le pourcentage d'eau absorbée par le sol et augmente le pourcentage d'eau qui reste en surface avec de mauvaises qualités correspondant aux inondations très fréquentes dans cette localité. Cependant, une étude complémentaire est nécessaire pour vérifier aussi la présence ou pas des métaux lourds et/ou des pesticides dans la nappe du Technopole afin de proposer un traitement adéquat de l’ensemble des contaminants.Mots clés— eaux souterraines, irrigation, potabilité, inondation, TechnopoleAbstract—The purpose of our study is to assess the quality of groundwater in the Technopole area for irrigation and possibly drinking in order to reduce the very frequent floods in this locality. Thus, the water quality of the Technopole aquifer is quite good for irrigation but very poor for human consumption. With the exception of conductivity (on average 4400 μS/cm  > 3000 μS/cm WHO guide value) and total phosphorus (on average 12.75 mg/L > 10 mg/L WHO guide value ), all other groundwater parameters comply with the WHO limit values for irrigation. On the other hand, concerning the potability parameters measured, only nitrates respect the limit which is 50 mg/L in certain points with an average of 46.4 mg/L. Indeed, we have thousands of U/100 mL of Escherichia coli when it should be absent in the drinking water. On the other hand, we also have very high TDS in the Technopole aquifer concentrations for the drink with an average of 3200 mg/L whereas it is generally considered good if it is below about 600 mg/L. This pollution is directly linked to wastewater discharges from the waste water treatment plant (WWTP) and agricultural activities, but also maintained by poor wastewater management in the area. Consequently, the non-use of water from the Technopole aquifer reduces the percentage of water absorbed by the ground and increases the percentage of water that remains on the surface with poor qualities corresponding to the very frequent floods in this locality. However, an additional study is necessary to also verify the presence or absence of heavy metals and/or pesticides in the Technopole groundwater in order to propose an adequate treatment of all contaminants.Keywords— groundwater, irrigation, potablity, flooding, Technopol

Addressing school water, sanitation and hygiene for the recovery phase in Haiti 2010

This paper examines the water, sanitation and hygiene situation in 42 schools in the West Department of Haiti, after the 12th January 2010 earthquake. The aim of the study is to provide an assessment of the water and sanitation facilities in the project schools, analyzing the different stakeholders involved, and to underline challenges and opportunities for project implementation during the recovery phase. Direct observations showed that schools lack safe drinking water, appropriate sanitation and hand washing facilities; likewise hygiene promotion is not included in the school curriculum. Semi-structured interviews with schools directors revealed that main constraints to improve the water, sanitation and hygiene services are related to lack of funding and infrastructures loss after the earthquake. Providing schools with water and sanitation facilities and supporting the implementation of hygiene promotion programmes, including a disaster risk reduction and preparedness plan, can play a significant role for a sustainable recovery phase

Technical and environmental characterisation of recycled aggregate for reuse in bricks

Waste mud coming from an aggregate washing plant was formerly used as filling material for a pond, aimed at the recovery of an abandoned quarry. Once completed the filling capacity of the pond, the need for identifying a possible reuse of mud produced by the plant arose in order to avoid landfill disposal. Therefore, mud has been geometrically, physically and chemically characterised for its recovery as construction material. A variety of tests was carried out on mud samples as required by EN technical specifications and by Italian environmental standards, focusing particularly on leaching behaviour. The tested material showed satisfactory physical and chemical properties and a release of pollutants below the limits set by the Italian code. Many mix-designs for the production of unfired bricks made of waste mud, sand and straw, stabilised and non-stabilised with lime, gypsum or cement, were developed. The bricks were tested in order to evaluate mechanical properties and leaching behaviour. Mud bricks provided remarkable compressive strength, even if not suitable for structural elements. The use as interior design to minimise humidity changes and to facilitate a thermal insulation is fostered, thus strengthening the so-called green building economy

Amélioration De La Qualité Des Eaux (Eaux Usées, Nappe Phréatique Et Lac) Par Phytoépuration Dans La Zone Du Technopole De Dakar (Sénégal)

L'assainissement municipal et la gestion des eaux usées sont des problèmes difficiles pour le développement environnemental durable dans les pays en développement. L’augmentation des rejets d’eaux usées non ou mal traitées par la station d’épuration (STEP) du Technopole de Dakar (Sénégal), combinée au ruissellement agricole ont entrainé la dégradation de la qualité des eaux de la nappe phréatique et du lac dans cette zone. Ainsi, la construction d'une installation pilote pour le traitement de ces eaux usées très chargées en polluants et produites par la station d’épuration des eaux usées du Technopole a été réalisé. La configuration du filtre horizontal est composée d’une fosse septique, d’une zone humide à flux horizontal submergé et d’un réservoir de stockage. Au terme de ce travail, nous avons un pourcentage global d’épuration de 69% des eaux usées mal traitées par la STEP à raison de 2 m3 par jour. En effet, la phytoépuration à travers le filtre horizontal a entrainé une réduction de 90,5% des MEST ; 63,4% de la DBO5 ;74,7% de la DCO ; 17,2% de l’azote total et 98,2% d'Escherichia Coli. Cependant, il restait toujours une quantité élevée d'Escherichia Coli et d’azote, par conséquent, un traitement tertiaire est recommandé, par exemple, la désinfection est suggérée par UV ou hypochlorite ou chlore pour une élimination des agents pathogènes mais aussi la nitification et la dénitrification

Assessment of Physical-Chemical Drinking Water Quality in the Logone Valley (Chad-Cameroon)

Unsafe drinking water is one of the main concerns in developing countries. In order to deal with this problem, a cooperation project was set up by the ACRA Foundation in the Logone valley (Chad-Cameroon). Water supplies were sampled throughout the villages of this area mostly from boreholes, open wells, rivers and lakes as well as some piped waters. The samples were analysed for their physical-chemical and microbiological quality in order to identify the contamination problems and suggest appropriate solutions. Results of the assessment confirmed that in the studied area there are several parameters of health and aesthetic concern. Elevated lead levels were detected both in aquifers and in surface waters, confirming that further investigations of the occurrence of lead contamination in the Logone valley are warranted. In addition, many groundwater sources are negatively impacted by parameters of aesthetic concern, such as turbidity, iron and manganese. Even though they do not affect human health, elevated levels of these parameters cause consumers to abandon improved water supplies, often in favour of surface water sources that are microbiologically contaminated. The use of alternative sources, improvement of water supply structures and water treatment are possible solutions to improve the quality of drinking water in the Logone valley