Browsing by Author "Lufingo, Mesia"

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Application of the Kilimanjaro Concept in Reversing Seawater Intrusion and Securing Water Supply in Zanzibar, Tanzania
(MDPI, 2021-07-30) Pembe-Ali, Zuleikha; Mwamila, Tulinave; Lufingo, Mesia; Gwenzi, Willis; Marwa, Janeth; Rwiza, Mwemezi; Lugodisha, Innocent; Qi, Qinwen; Noubactep, Chicgoua
There is escalating salinity levels on small islands due to uncontrolled groundwater extraction. Conventionally, this challenge is addressed by adopting optimal groundwater pumping strategies. Currently, on Unguja Island (Zanzibar), urban freshwater is supplied by desalination, which is expensive and energy-intensive. Hence, desalinization cannot be afforded by rural communities. This study demonstrates that the innovative Kilimanjaro Concept (KC), based on rainwater harvesting (RWH) can remediate seawater intrusion in Unguja, while enabling a universal safe drinking water supply. The reasoning is rooted in the water balance of the whole island. It is shown that if rainwater is systematically harvested, quantitatively stored, and partly infiltrated, seawater intrusion will be reversed, and a universal safe drinking water supply will be secured. Water treatment with affordable technologies (e.g., filtration and adsorption) is suggested. The universality of KC and its suitability for small islands is demonstrated. Future research should focus on pilot testing of this concept on Unguja Island and other island nations.
Avoiding the Use of Exhausted DrinkingWater Filters: A Filter-Clock Based on Rusting Iron
(MDPI, 2018-05-02) Ndé-Tchoupé, Arnaud Igor; Lufingo, Mesia; Hu, Rui; Gwenzi, Willis; Ntwampe, Seteno Karabo Obed; Noubactep, Chicgoua; Njau, Karoli
Efficient but affordable water treatment technologies are currently sought to solve the prevalent shortage of safe drinking water. Adsorption-based technologies are in the front-line of these efforts. Upon proper design, universally applied materials (e.g., activated carbons, bone chars, metal oxides) are able to quantitatively remove inorganic and organic pollutants as well as pathogens from water. Each water filter has a defined removal capacity and must be replaced when this capacity is exhausted. Operational experience has shown that it may be difficult to convince some low-skilled users to buy new filters after a predicted service life. This communication describes the quest to develop a filter-clock to encourage all users to change their filters after the designed service life. A brief discussion on such a filter-clock based on rusting of metallic iron (Fe0) is presented. Integrating such filter-clocks in the design of water filters is regarded as essential for safeguarding public health.
Defeating Fluorosis in the East African Rift Valley: Transforming the Kilimanjaro into a Rainwater Harvesting Park
(MDPI, 2018-11-14) Marwa, Janeth; Lufingo, Mesia; Noubactep, Chicgoua; Machunda, Revocatus
The high availability of fluoride in surface and groundwater in the East African Rift Valley was documented during the colonial period. Since the early 1960s, many studies have been conducted to solve the fluorosis crisis in this region. At present, no cost-effective solution to mitigate fluoride contamination is available for the large majority of the population. This situation prompted a process analysis of commonly used technologies. Results revealed that the geochemistry of fluoride is the main problem. Fluoride is very difficult to remove from the aqueous phase. Thus, eliminating the need for technical water defluoridation is an excellent way out of the fluorosis crisis. This goal can be achieved by harvesting fluoride-free rainwater. Harvested rainwater can be mixed with naturally polluted waters in calculated proportions to obtain safe drinking water (blending). This paper presents a concept to transform the Kilimanjaro Mountains into a huge rainwater harvesting park for drinking water supply for the whole East African Rift Valley. However, blended water may contain other pollutants including pathogens that are easy to treat using low-cost methods such as metallic iron based-filters (Fe0 filters). The proposed concept is transferable to other parts of the world still enduring fluoride pollution.
Hydrogeochemical Analysis of Water Quality Dynamics Under Anthropic Activities on the Southern Slopes of Mount Kilimanjaro, Tanzania
(Springer Nature, 2022-07-14) Said, Mateso; Komakech, Hans; Mjemah, Ibrahimu; Lufingo, Mesia; Munishi, Linus; Kumar, Sudhir
Water quality management requires consideration of surface water and groundwater dynamics. This study utilizes hydrogeochemical and isotopic techniques to understand anthropic influences on surface and groundwater resources in the Kikafu–Weruweru–Karanga (KWK) watershed southern slopes of Mount Kilimanjaro. The KWK watershed had two distinct characteristics, i.e., the upper region (above 1000 m.a.m.s.l) with surface water and few groundwater features and the lower part (below 1000 m.a.m.s.l) characterized by most groundwater sources and rivers. Water sampling and analysis were done between July and August 2019; multivariate statistical analysis aided the understanding of analytical findings. The results revealed NaHCO3 enrichment and Mixed CaNaHCO3 water type. The groundwater chemistry is chiefly controlled by aquifer lithology rather than anthropic activities. Stable isotopes show recharge from both regional and local rainfall as traced from the shallow wells. The levels of anthropic pollution indicators such as nitrate, chloride, and sulfate in deep wells are generally low in groundwater than in shallow wells. Anthropic activities such as irrigation, wastewater discharges and severe water abstraction confirmed significant contaminant agents at the dynamic levels. Next to geogenic releases, anthropic pollution as well is affecting groundwater quality in the aquifer. The current findings call for improved monitoring of the groundwater sources to track any changes in quality since there is a potential evolution to an undesirable state for domestic uses.
Investigation of metallic iron for water defluoridation
(NM-AIST, 2021-12) Lufingo, Mesia
Fluorosis is a significant ailment that affects millions of humans and animals, especially in low income countries. It has been the focus of past and present scientific endeavours to research and develop efficient and deployable technologies, especially in these low-income communities. In this work, metallic Iron (Fe0) is a promising technology, and its filters have successfully addressed both safe drinking water and sanitation and are frugal. The recalled science of Fe0 filters is demonstrated with the lingering design investigations. This study aimed at the critical assessment on defluoridation efficiencies under conventional metallic iron aqueous systems; where at first, Fe0 materials were characterized with 1,10 Phenanthroline (Phen) in aqueous condition, and later batch studies were realized at the laboratory scale for two days under varied experimental conditions of: (a) 0.1 g and 1.0 g of iron mass, (b) Equimolar contamination, 23±2.0 mg/L, of co-solutes, i.e. NO3, PO4, SO4, HCO3, Cl, (c) Initial pH values of 4.5, 7.0 and 9.5, and (d) Disturbed and non-disturbed treatments. Characterization results proved the potential of 1,10-Phenanthroline as a sole Fe0 novel and facile characterization method. Defluoridation results revealed a maximum of 94% and 47% for quantitative (involving co precipitation, adsorption and occasionally size-exclusion remediations) and non-quantitative (associated with adsorption as major remediation means) fluoride removal efficiencies, respectively. Thus, a conventional metallic iron aqueous system requires incorporating suggested nano-scale practices towards enhancing efficiency for affordable defluoridation achievements in future continuous system designs.
A Novel and Facile Method to Characterize the Suitability of Metallic Iron for Water Treatment
(MDPI, 2019-11-23) Lufingo, Mesia; Ndé-Tchoupé, Arnaud Igor; Hu, Rui; Njau, Karoli; Noubactep, Chicgoua
Metallic iron (Fe0) materials have been industrially used for water treatment since the 1850s. There are still many fundamental challenges in affordably and reliably characterizing the Fe0 intrinsic reactivity. From the available methods, the one using Fe0 dissolution in ethylenediaminetetraacetic acid (EDTA—2 mM) was demonstrated the most applicable as it uses only four affordable chemicals: Ascorbic acid, an ascorbate salt, EDTA and 1,10-Phenanthroline (Phen). A careful look at these chemicals reveals that EDTA and Phen are complexing agents for dissolved iron species. Fe3-EDTA is very stable and difficult to destabilize; ascorbic acid is one of the few appropriate reducing agents, therefore. On the other hand, the Fe2-Phen complex is so stable that oxidation by dissolved O2 is not possible. This article positively tests Fe0 (0.1 g) dissolution in 2 mM Phen (50 mL) as a characterization tool for the intrinsic reactivity, using 9 commercial steel wool (Fe0 SW) specimens as probe materials. The results are compared with those obtained by the EDTA method. The apparent iron dissolution rate in EDTA (kEDTA) and in Phen (kPhen) were such that 0.53 ≤ kEDTA (μg h−1) ≤ 4.81 and 0.07 ≤ kPhen (μg h−1) ≤ 1.30. Higher kEDTA values, relative to kPhen, are a reflection of disturbing Fe3 species originating from Fe2 oxidation by dissolved O2 and dissolution of iron corrosion products. It appears that the Phen method considers only the forward dissolution of Fe0. The Phen method is reliable and represents the most affordable approach for characterizing the suitability of Fe0 for water treatment.
White Teeth and Healthy Skeletons for All: The Path to Universal Fluoride-Free DrinkingWater in Tanzania
(MDPI, 2019-01-12) Ndé-Tchoupé, Arnaud Igor; Tepong-Tsindé, Raoul; Lufingo, Mesia; Pembe-Ali, Zuleikha; Lugodisha, Innocent; Mureth, Risala Iddi; Nkinda, Mihayo; Marwa, Janeth; Gwenzi, Willis; Mwamila, Tulinave Burton; Rahman, Mohammad Azizur; Noubactep, Chicgoua; Njau, Karoli
Fluorosis has been prevalent in the great East African Rift Valley (EARV) since before this region was given a name. In the Tanganyika days, Germans reported elevated fluoride concentrations in natural waters. In the 1930s, the clear relationship between high fluoride level and mottling of teeth was established. Since then, the global research community has engaged in the battle to provide fluoride-free drinking water, and the battle is not yet won for low-income communities. An applicable concept for fluoride-free drinking water in the EARV was recently presented, using the Kilimanjaro as a rainwater harvesting park. The Kilimanjaro concept implies that rainwater is harvested, stored on the Kilimanjaro mountains, gravity-transported to the point of use, eventually blended with natural water and treated for distribution. This article provides a roadmap for the implementation of the Kilimanjaro concept in Tanzania. Specifically, the current paper addresses the following: (i) presents updated nationwide information on fluoride contaminated areas, (ii) discusses the quality and quantity of rainwater, and current rainwater harvesting practices in Tanzania, (iii) highlights how low-cost water filters based on Fe0/biochar can be integrating into rainwater harvesting (RWH) systems to provide clean drinking water, and (iv) discusses the need for strict regulation of RWH practices to optimize water collection and storage, while simplifying the water treatment chain, and recommends strict analytical monitoring of water quality and public education to sustain public health in the EARV. In summary, it is demonstrated that, by combining rainwater harvesting and low-cots water treatment methods, the Kilimanjaro concept has the potential to provide clean drinking water, and overcome fluorosis on a long-term basis. However, a detailed design process is required to determine: (i) institutional roles, and community contributions and participation, (ii) optimal location and sizing of conveyance and storage facilities to avoid excessive pumping costs, and (iii) project funding mechanisms, including prospects for government subsidy. By drawing attention to the Kilimanjaro concept, the article calls for African engineers and scientists to take the lead in translating this concept into reality for the benefit of public health, while simultaneously increasing their self-confidence to address other developmental challenges pervasive in Africa.