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This study investigated the levels of Pb, Hg, Cr, Cd, and As in water and sediments from the tributaries of the Mara River, Tanzania. Pollution risk of water and sediments was investigated using seven indices and five metals. During the dry period, the highest concentration of Pb, Hg, Cr, Cd, and As in sediments was 17.45 ± 1.22, 0.01, 1.56 ± 0.5, 1.3 ± 0.09, and 30.81 ± 0.02 mg/kg, respectively. During the wet period, the highest concentration of Pb, Hg, Cr, Cd, and As in sediments was 4.37 ± 0.28, 0.012, 2.58 ± 0.57, 2.25 ± 0.35, and 53 ± 0.02 mg/kg, respectively. For surface water, the respective highest concentrations of Pb, Hg, Cr, Cd, and As were 0.76 ± 0.09, 0.04, 0.68 ± 0.09, 0.74 ± 0.1, and 0.47 ± 0.06 mg/L for the dry period. The wet period max concentrations for Pb, Hg, Cr, Cd, and As in surface water were 0.56, 0.03, 0.55 ± 0.03, 0.48 ± 0.03, and 0.4 ± 0.03 mg/L, respectively. Principal component analysis results indicated dominant loadings for Pb and As in sediments during the dry period. Comparison of sediment concentrations with sediment quality guidelines revealed that As and Cd were enriched. Correlation coefficient results indicated that As had a strong negative correlation with the rest of the elements in sediments during the dry period. In the wet period, As had a significant correlation with Cd (r = 0.92, p < 0.01) in sediments. The analysis of environmental risks indicated significant enrichment of sediments with As and Cd. It is important to put in place relevant control mechanisms targeting metals in the studied tributaries, with a focus on As and Cd.
Mihayo Sahani Nkinda; Mwemezi Johaiven Rwiza; Jasper Nathan Ijumba; Karoli Nicholas Njau. Heavy metals risk assessment of water and sediments collected from selected river tributaries of the Mara River in Tanzania. Discover Water 2021, 1, 1 -20.
AMA StyleMihayo Sahani Nkinda, Mwemezi Johaiven Rwiza, Jasper Nathan Ijumba, Karoli Nicholas Njau. Heavy metals risk assessment of water and sediments collected from selected river tributaries of the Mara River in Tanzania. Discover Water. 2021; 1 (1):1-20.
Chicago/Turabian StyleMihayo Sahani Nkinda; Mwemezi Johaiven Rwiza; Jasper Nathan Ijumba; Karoli Nicholas Njau. 2021. "Heavy metals risk assessment of water and sediments collected from selected river tributaries of the Mara River in Tanzania." Discover Water 1, no. 1: 1-20.
Nitrate isotopic values are often used as a tool to identify sources of nitrate in order to effectively manage ground water quality. In this study, the concentrations of NO3−, NO2−, and NH4+ from 50 boreholes and shallow wells in the Singida and Manyoni Districts were analyzed during the dry and wet seasons, followed by identification of nitrate sources using the hydrochemical method (NO3−/Cl−) and stable isotope (δ15N and δ18O) techniques. Results showed that NO2− and NH4+ concentrations were very low in both seasons due to the nitrification process. The concentrations of NO3− ranged from 2.4 ppm to 929.6 ppm with mean values of 118.5 ppm ± 118.5 ppm , during the dry season and from 2.4 ppm to 1620.0 ppm with mean values of 171.6 ppm ± 312.3 ppm , during the wet season. The higher NO3− contamination observed in the wet season could be due to rainfall which accelerated the surface runoff that collects different materials from various settings into the ground water sources. Nitrate source identification through hydrochemical technique revealed that most nitrates originated from sewage effluents and/or organic wastes such as manure. Likewise, the mean values of δ15N-NO3− ( + 20.90 ‰ ± 5.17 ‰ and + 18.30 ‰ ± 6.33 ‰ ) and the mean values of δ18O-NO3−( + 13.86 ‰ ± 3.18 ‰ and + 13.69 ‰ ± 3.97 ‰ ) suggest that 80% of boreholes and 52% of shallow wells were dominated with nitrate from sewage effluents and/or manure as most ground water sources were situated in densely populated areas with congested and poorly constructed onsite sanitation facilities such as pit latrines and manure. Therefore, to reduce nitrate pollution in the study area, a central sewer must be constructed to treat the discharged wastes. Also, groundwater harvesting should consider the proper principles for groundwater harvesting recommended by the respective authority to minimize chances of contamination and hence prevention of health risk.
Rita Alex; Aldo Kitalika; Emmanuel Mogusu; Karoli Njau. Sources of Nitrate in Ground Water Aquifers of the Semiarid Region of Tanzania. Geofluids 2021, 2021, 1 -20.
AMA StyleRita Alex, Aldo Kitalika, Emmanuel Mogusu, Karoli Njau. Sources of Nitrate in Ground Water Aquifers of the Semiarid Region of Tanzania. Geofluids. 2021; 2021 ():1-20.
Chicago/Turabian StyleRita Alex; Aldo Kitalika; Emmanuel Mogusu; Karoli Njau. 2021. "Sources of Nitrate in Ground Water Aquifers of the Semiarid Region of Tanzania." Geofluids 2021, no. : 1-20.
Banana leaves wastes (BL) were subjected to fungal treatment using Pleurotus ostreatus to produce edible mushrooms and biogas in the anaerobic digestion process. Effects of fungal treatment on mushrooms production, lignin degradation, trace elements compositions and biogas yield during the anaerobic digestion process were evaluated. Treatment with P.ostreatus for 36 d resulted in the production of 181 ± 19 g of edible mushrooms per 2 kg of BL with biological efficiency of 37 ± 4%. Lignin concentration in fungal treated BL decreased by 10% indicating an improvement on its digestibility. Important trace elements (Fe, Mn, Mo, Co and Ni) necessary for the improvement of the anaerobic digestion process were also significantly reduced (P < 0.05) during the fungal treatment process. The biogas yield for the fungal treated BL was 282 mL g−1 VS−1 of which this study suggests that could be improved through trace element supplementation during the anaerobic digestion process.
Edwin N. Richard; Askwar Hilonga; Revocatus L. Machunda; Karoli N. Njau. Two-stage banana leaves wastes utilization towards mushroom growth and biogas production. 3 Biotech 2020, 10, 1 -8.
AMA StyleEdwin N. Richard, Askwar Hilonga, Revocatus L. Machunda, Karoli N. Njau. Two-stage banana leaves wastes utilization towards mushroom growth and biogas production. 3 Biotech. 2020; 10 (12):1-8.
Chicago/Turabian StyleEdwin N. Richard; Askwar Hilonga; Revocatus L. Machunda; Karoli N. Njau. 2020. "Two-stage banana leaves wastes utilization towards mushroom growth and biogas production." 3 Biotech 10, no. 12: 1-8.
Formative research findings from the fast-growing Babati town were used to assess the prevalence of sanitation and hygiene practices among individuals and institutions and associated factors. A cross-sectional study involving household surveys, spot-checks, focus group discussions, in-depth interviews, and structured observations of behaviors showed that 90% of households have sanitation facilities, but 68% have safely managed sanitation services. The most common types of household sanitation facilities were pit latrines with slab (42%) followed by flush/pour flush toilets (32%). Therefore, the management of wastewater depends entirely on onsite sanitation systems. The majority of households (70%) do not practice proper hygiene behaviors. Thirteen percent of the households had handwashing stations with soap and water, handwashing practice being more common to women (38%) than men (18%). The reported handwashing practices during the four critical moments (handwashing with soap before eating and feeding, after defecation, after cleaning child’s bottom, and after touching any dirt/dust) differed from the actual/observed practices. Households connected to the town’s piped water supply were more likely to practice handwashing than those not directly connected. Sanitation and hygiene behaviors of the people in the study area were seen to be influenced by sociodemographic, cultural, and economic factors. The conditions of sanitation and hygiene facilities in public places were unsatisfactory. There is an urgent need to ensure that the sanitation and hygiene services and behaviors along the value chain (from waste production/source to disposal/end point) are improved both at the household level and in public places through improved sanitation services and the promotion of effective hygiene behavior change programs integrated into ongoing government programs and planning.
Hoyce Mshida; Gabriel Malima; Revocatus Machunda; Alfred N. N. Muzuka; Joseph Banzi; Om Prasad Gautam; Mbaye Mbeguere; Kyla Smith; Sandy Cairncross; Edward S. Shana; Amadeus Herman; Karoli N. Njau. Sanitation and Hygiene Practices in Small Towns in Tanzania: The Case of Babati District, Manyara Region. The American Journal of Tropical Medicine and Hygiene 2020, 103, 1726 -1734.
AMA StyleHoyce Mshida, Gabriel Malima, Revocatus Machunda, Alfred N. N. Muzuka, Joseph Banzi, Om Prasad Gautam, Mbaye Mbeguere, Kyla Smith, Sandy Cairncross, Edward S. Shana, Amadeus Herman, Karoli N. Njau. Sanitation and Hygiene Practices in Small Towns in Tanzania: The Case of Babati District, Manyara Region. The American Journal of Tropical Medicine and Hygiene. 2020; 103 (4):1726-1734.
Chicago/Turabian StyleHoyce Mshida; Gabriel Malima; Revocatus Machunda; Alfred N. N. Muzuka; Joseph Banzi; Om Prasad Gautam; Mbaye Mbeguere; Kyla Smith; Sandy Cairncross; Edward S. Shana; Amadeus Herman; Karoli N. Njau. 2020. "Sanitation and Hygiene Practices in Small Towns in Tanzania: The Case of Babati District, Manyara Region." The American Journal of Tropical Medicine and Hygiene 103, no. 4: 1726-1734.
The energy demand, which is expected to increase more worldwide, has sparked the interest of researchers to find sustainable and inexpensive sources of energy. This study aims to integrate an energy recovering step into municipal wastewater treatment plants (MWWTPS) through anaerobic digestion. The anaerobic digestion of municipal wastewater (MWW), and then co-digestion with sugar cane molasses (SCM) to improve its organic content, was conducted at 25 °C and 37 °C. The results showed a substrate mixture containing 6% of SCM and total solids (TS) of 7.52% yielded a higher amount of biogas (9.73 L/L of modified substrate). However, chemical oxygen demand (COD) of the resulting digestate was high (10.1 g/L) and pH was not stable, and hence needed careful adjustment using 2 M of NaOH solution. This study recommends a substrate mixture containing SCM (2%) and TS (4.34%) having biogas production (4.97 L/L of modified substrate) for energy recovery from MWWTPS, since it was found to have more stable pH and low COD residue (1.8 g/L), which will not hold back the MWW treatment process. The annual generation of modified substrate (662,973 m3) is anticipated to generate about 16,241 m3 of methane, which produces up to 1.8 GWh and 8,193 GJ per annum.
Vaileth Hance; Thomas Kivevele; Karoli Nicholas Njau. Modification of municipal wastewater for improved biogas recovery. Water Practice and Technology 2020, 15, 1 .
AMA StyleVaileth Hance, Thomas Kivevele, Karoli Nicholas Njau. Modification of municipal wastewater for improved biogas recovery. Water Practice and Technology. 2020; 15 (3):1.
Chicago/Turabian StyleVaileth Hance; Thomas Kivevele; Karoli Nicholas Njau. 2020. "Modification of municipal wastewater for improved biogas recovery." Water Practice and Technology 15, no. 3: 1.
Chrome tanning remains the most favourite technology in the leather industry worldwide due to its ability to produce leather with attributes desirable for high-quality leather such as excellent hydrothermal stability, better dyeing characteristics and softness. Nevertheless, the technology has been censured globally for its severe environmental detriments and adverse effects on human health and other organisms. Developing alternative eco-friendly tanning technologies capable of producing leather of high quality has remained a challenging scientific inquiry. This review article provides an assessment of various eco-friendly tanning attempts geared towards improving or replacing the chrome technology without compromising the quality of the produced leather. The reviewed publications have ascertained that, these attempts have been centred on recycling of spent liquors; chromium exhaustion enhancement and total replacement of chromium salts. The research gaps and levels of key environmental pollutants from the reviewed technologies are presented, and the qualities of the leather produced from these technologies are highlighted. Of all the examined alternative technologies, total replacement of chromium salts sounds ideal to elude adverse effects associated with chrome tanning. Combination tanning, which implies blending two tanning agents that individually cannot impart desired properties to the leather, is anticipated to be an alternative technology to chrome tanning. Apart from being an eco-friendly technology, combination tanning produces leather with similar features to those produced by chrome tanning. In this regard, blending vegetable tannins with aluminium sulphate provides a promising chrome-free tanning technology. However, further studies to optimize combination tanning technologies to suit industrial applications are highly recommended.
Cecilia Rolence China; Mihayo Musabila Maguta; Stephen Samwel Nyandoro; Askwar Hilonga; Swarna V. Kanth; Karoli N. Njau. Alternative tanning technologies and their suitability in curbing environmental pollution from the leather industry: A comprehensive review. Chemosphere 2020, 254, 126804 .
AMA StyleCecilia Rolence China, Mihayo Musabila Maguta, Stephen Samwel Nyandoro, Askwar Hilonga, Swarna V. Kanth, Karoli N. Njau. Alternative tanning technologies and their suitability in curbing environmental pollution from the leather industry: A comprehensive review. Chemosphere. 2020; 254 ():126804.
Chicago/Turabian StyleCecilia Rolence China; Mihayo Musabila Maguta; Stephen Samwel Nyandoro; Askwar Hilonga; Swarna V. Kanth; Karoli N. Njau. 2020. "Alternative tanning technologies and their suitability in curbing environmental pollution from the leather industry: A comprehensive review." Chemosphere 254, no. : 126804.
Over the recent era, Wireless Sensor Network (WSN) has attracted much attention among industrialists and researchers owing to its contribution to numerous applications including military, environmental monitoring and so on. However, reducing the network delay and improving the network lifetime are always big issues in the domain of WSN. To resolve these downsides, we propose an Energy-Efficient Scheduling using the Deep Reinforcement Learning (DRL) (E2S-DRL) algorithm in WSN. E2S-DRL contributes three phases to prolong network lifetime and to reduce network delay that is: the clustering phase, duty-cycling phase and routing phase. E2S-DRL starts with the clustering phase where we reduce the energy consumption incurred during data aggregation. It is achieved through the Zone-based Clustering (ZbC) scheme. In the ZbC scheme, hybrid Particle Swarm Optimization (PSO) and Affinity Propagation (AP) algorithms are utilized. Duty cycling is adopted in the second phase by executing the DRL algorithm, from which, E2S-DRL reduces the energy consumption of individual sensor nodes effectually. The transmission delay is mitigated in the third (routing) phase using Ant Colony Optimization (ACO) and the Firefly Algorithm (FFA). Our work is modeled in Network Simulator 3.26 (NS3). The results are valuable in provisions of upcoming metrics including network lifetime, energy consumption, throughput and delay. From this evaluation, it is proved that our E2S-DRL reduces energy consumption, reduces delays by up to 40% and enhances throughput and network lifetime up to 35% compared to the existing cTDMA, DRA, LDC and iABC methods.
Ramadhani Sinde; Feroza Begum; Karoli Njau; Shubi Kaijage. Refining Network Lifetime of Wireless Sensor Network Using Energy-Efficient Clustering and DRL-Based Sleep Scheduling. Sensors 2020, 20, 1540 .
AMA StyleRamadhani Sinde, Feroza Begum, Karoli Njau, Shubi Kaijage. Refining Network Lifetime of Wireless Sensor Network Using Energy-Efficient Clustering and DRL-Based Sleep Scheduling. Sensors. 2020; 20 (5):1540.
Chicago/Turabian StyleRamadhani Sinde; Feroza Begum; Karoli Njau; Shubi Kaijage. 2020. "Refining Network Lifetime of Wireless Sensor Network Using Energy-Efficient Clustering and DRL-Based Sleep Scheduling." Sensors 20, no. 5: 1540.
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.
Mesia Lufingo; Arnaud Igor Ndé-Tchoupé; Rui Hu; Karoli N. Njau; Chicgoua Noubactep. A Novel and Facile Method to Characterize the Suitability of Metallic Iron for Water Treatment. Water 2019, 11, 2465 .
AMA StyleMesia Lufingo, Arnaud Igor Ndé-Tchoupé, Rui Hu, Karoli N. Njau, Chicgoua Noubactep. A Novel and Facile Method to Characterize the Suitability of Metallic Iron for Water Treatment. Water. 2019; 11 (12):2465.
Chicago/Turabian StyleMesia Lufingo; Arnaud Igor Ndé-Tchoupé; Rui Hu; Karoli N. Njau; Chicgoua Noubactep. 2019. "A Novel and Facile Method to Characterize the Suitability of Metallic Iron for Water Treatment." Water 11, no. 12: 2465.
Leather making commonly use chromium salts to produce high quality products. However, the use of chromium salts is compromised by environmental safety concerns. Combination tanning using vegetable tanning coupled with aluminium sulphate can sustainably replace chrome tanning system. Adversely, the use of commercial aluminium sulphate poses economic burden that entails for cost effective sources. Abundance of kaolin on earth’s crust with scarce utilization is an opportunity towards cost effective aluminium sulphate for tanning. Therefore, in the present work aluminium sulphate was prepared from kaolin and its performance for combination tanning was studied. Diffraction and vibrational spectroscopic studies were carried out to confirm the prepared aluminium sulphate. Combination tanning was carried out with mimosa vegetable tannins. Leathers tanned with the combination of aluminium sulphate from kaolin and mimosa vegetable tannin exhibited hydrothermal stability of up to 118 °C as compared to mimosa alone that showed the average of 80 °C. Physical strength characteristics met the standard norms. Fibers separation was good as confirmed through microscopic studies. The study provides a new insight on accomplishing self-sustenance through available resources and eco-friendly manufacturing system.
Cecilia R. China; Askwar Hilonga; Mihayo M. Maguta; Stephen S. Nyandoro; Swarna V. Kanth; Gladstone C. Jayakumar; Karoli N. Njau. Preparation of aluminium sulphate from kaolin and its performance in combination tanning. SN Applied Sciences 2019, 1, 920 .
AMA StyleCecilia R. China, Askwar Hilonga, Mihayo M. Maguta, Stephen S. Nyandoro, Swarna V. Kanth, Gladstone C. Jayakumar, Karoli N. Njau. Preparation of aluminium sulphate from kaolin and its performance in combination tanning. SN Applied Sciences. 2019; 1 (8):920.
Chicago/Turabian StyleCecilia R. China; Askwar Hilonga; Mihayo M. Maguta; Stephen S. Nyandoro; Swarna V. Kanth; Gladstone C. Jayakumar; Karoli N. Njau. 2019. "Preparation of aluminium sulphate from kaolin and its performance in combination tanning." SN Applied Sciences 1, no. 8: 920.
Studies were undertaken to determine the reasons why published information regarding the efficiency of metallic iron (Fe0) for water treatment is conflicting and even confusing. The reactivity of eight Fe0 materials was characterized by Fe dissolution in a dilute solution of ethylenediaminetetraacetate (Na2–EDTA; 2 mM). Both batch (4 days) and column (100 days) experiments were used. A total of 30 different systems were characterized for the extent of Fe release in EDTA. The effects of Fe0 type (granular iron, iron nails and steel wool) and pretreatment procedure (socking in acetone, EDTA, H2O, HCl and NaCl for 17 h) were assessed. The results roughly show an increased iron dissolution with increasing reactive sites (decreasing particle size: wool > filings > nails), but there were large differences between materials from the same group. The main output of this work is that available results are hardly comparable as they were achieved under very different experimental conditions. A conceptual framework is presented for future research directed towards a more processed understanding.
Rui Hu; Arnaud Igor Ndé-Tchoupé; Mesia Lufingo; Minhui Xiao; Achille Nassi; Chicgoua Noubactep; Karoli N. Njau. The Impact of Selected Pretreatment Procedures on Iron Dissolution from Metallic Iron Specimens Used in Water Treatment. Sustainability 2019, 11, 671 .
AMA StyleRui Hu, Arnaud Igor Ndé-Tchoupé, Mesia Lufingo, Minhui Xiao, Achille Nassi, Chicgoua Noubactep, Karoli N. Njau. The Impact of Selected Pretreatment Procedures on Iron Dissolution from Metallic Iron Specimens Used in Water Treatment. Sustainability. 2019; 11 (3):671.
Chicago/Turabian StyleRui Hu; Arnaud Igor Ndé-Tchoupé; Mesia Lufingo; Minhui Xiao; Achille Nassi; Chicgoua Noubactep; Karoli N. Njau. 2019. "The Impact of Selected Pretreatment Procedures on Iron Dissolution from Metallic Iron Specimens Used in Water Treatment." Sustainability 11, no. 3: 671.
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.
Arnaud Igor Ndé-Tchoupé; Raoul Tepong-Tsindé; Mesia Lufingo; Zuleikha Pembe-Ali; Innocent Lugodisha; Risala Iddi Mureth; Mihayo Nkinda; Janeth Marwa; Willis Gwenzi; Tulinave Burton Mwamila; Mohammad Azizur Rahman; Chicgoua Noubactep; Karoli N. Njau. White Teeth and Healthy Skeletons for All: The Path to Universal Fluoride-Free Drinking Water in Tanzania. Water 2019, 11, 131 .
AMA StyleArnaud Igor Ndé-Tchoupé, Raoul Tepong-Tsindé, Mesia Lufingo, Zuleikha Pembe-Ali, Innocent Lugodisha, Risala Iddi Mureth, Mihayo Nkinda, Janeth Marwa, Willis Gwenzi, Tulinave Burton Mwamila, Mohammad Azizur Rahman, Chicgoua Noubactep, Karoli N. Njau. White Teeth and Healthy Skeletons for All: The Path to Universal Fluoride-Free Drinking Water in Tanzania. Water. 2019; 11 (1):131.
Chicago/Turabian StyleArnaud Igor Ndé-Tchoupé; Raoul Tepong-Tsindé; Mesia Lufingo; Zuleikha Pembe-Ali; Innocent Lugodisha; Risala Iddi Mureth; Mihayo Nkinda; Janeth Marwa; Willis Gwenzi; Tulinave Burton Mwamila; Mohammad Azizur Rahman; Chicgoua Noubactep; Karoli N. Njau. 2019. "White Teeth and Healthy Skeletons for All: The Path to Universal Fluoride-Free Drinking Water in Tanzania." Water 11, no. 1: 131.
The study of spatial land use and land change is inevitable for sustainable development of land use plans. Environmental transitions analysis was done in part of the land on the slopes of the foothills of Mount Meru in thirty (30) years’ time from 1986 to 2016 using satellite-derived land use/cover maps and a Cellular Automata (CA) spatial filter under IDRISI software environment and assessed the important land use changes. Also, the future land use for 2026 which is the next ten (10) years was simulated based on Cellular-Automata Markov model. The results showed significant land use transitions whereby there is a huge land use change of bush land (BL) and agriculture land (AG) into human settlement (ST) which resulted into conversion of Arusha town into a City. In addition, the changes have caused slight changes in water bodies into mixed forest. Moreover, the future land use/land cover (LULC) simulations indicated that there will be unsustainable LULC changes in the next ten years since most of bush land and part of agriculture land will be used for building different structures thus interfering with fresh water and food availability in the City. These changes call upon the relevant planning authorities to put in place the best strategies for good urban development.
Aldo. J. Kitalika; Revocatus. L. Machunda; Hans. C. Komakech; Karoli. N. Njau. Land-Use and Land Cover Changes on the Slopes of Mount Meru-Tanzania. Current World Environment 2018, 13, 331 -352.
AMA StyleAldo. J. Kitalika, Revocatus. L. Machunda, Hans. C. Komakech, Karoli. N. Njau. Land-Use and Land Cover Changes on the Slopes of Mount Meru-Tanzania. Current World Environment. 2018; 13 (3):331-352.
Chicago/Turabian StyleAldo. J. Kitalika; Revocatus. L. Machunda; Hans. C. Komakech; Karoli. N. Njau. 2018. "Land-Use and Land Cover Changes on the Slopes of Mount Meru-Tanzania." Current World Environment 13, no. 3: 331-352.
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.
Arnaud Igor Ndé-Tchoupé; Mesia Lufingo; Rui Hu; Willis Gwenzi; Seteno Karabo Obed Ntwampe; Chicgoua Noubactep; Karoli N. Njau. Avoiding the Use of Exhausted Drinking Water Filters: A Filter-Clock Based on Rusting Iron. Water 2018, 10, 591 .
AMA StyleArnaud Igor Ndé-Tchoupé, Mesia Lufingo, Rui Hu, Willis Gwenzi, Seteno Karabo Obed Ntwampe, Chicgoua Noubactep, Karoli N. Njau. Avoiding the Use of Exhausted Drinking Water Filters: A Filter-Clock Based on Rusting Iron. Water. 2018; 10 (5):591.
Chicago/Turabian StyleArnaud Igor Ndé-Tchoupé; Mesia Lufingo; Rui Hu; Willis Gwenzi; Seteno Karabo Obed Ntwampe; Chicgoua Noubactep; Karoli N. Njau. 2018. "Avoiding the Use of Exhausted Drinking Water Filters: A Filter-Clock Based on Rusting Iron." Water 10, no. 5: 591.
Agroprocessing constitutes sizeable industries in the Eastern Africa region discharging wastes into the environment. Proper management of industrial waste is perceived as expensive and enforcement of laws is weak. Generally, there is low awareness of environmental and socio-economic consequences of polluting the environment. The Banana Investment Limited (BIL) in Arusha Tanzania which produces banana wine from ripe bananas was discharging untreated wastewater into the environment. This project aimed at treating the BIL wastewater to meet environmental standards and recover nutrients, water and energy. The feeding wastewater to the up-flow anaerobic sludge blanket (UASB) with flow rate of 62.4 m3/d had concentrations (mg/L) of chemical oxygen demand (COD) (4,959.3 ± 388.7), BOD5 (1,453.7 ± 110.3), total suspended solids (TSS) (2,431.0 ± 190.5), NH4+ (7.2 ± 1.1), NO3− (23.4 ± 3.2), PO43− (5.12 ± 0.73), volatile fatty acid (0.60 ± 0.09), and Alkalinity (60.00 ± 8.98). After 17 months of operation the system achieved removal efficiencies (%) of COD (99.0), BOD5 (98.6), TSS (96.0), NO3− (88.7), PO43− (50.8). There was a net generation of NH4+ (387.8%) in the system. The biogas produced in the UASB is collected at a rate of 163 m3/d and is used in the boiler at BIL. The dried sludge and the treated water are used for irrigation. The study concluded that integrating the bio-digestion process with polishing stage for water, nutrient and energy recovery ensures compliance to environmental law and provides incentive to treat wastewater while also mitigating greenhouse gases.
C. Paschal; L. Gastory; J. H. Y. Katima; K. N. Njau. Application of up-flow anaerobic sludge blanket reactor integrated with constructed wetland for treatment of banana winery effluent. Water Practice and Technology 2017, 12, 667 -674.
AMA StyleC. Paschal, L. Gastory, J. H. Y. Katima, K. N. Njau. Application of up-flow anaerobic sludge blanket reactor integrated with constructed wetland for treatment of banana winery effluent. Water Practice and Technology. 2017; 12 (3):667-674.
Chicago/Turabian StyleC. Paschal; L. Gastory; J. H. Y. Katima; K. N. Njau. 2017. "Application of up-flow anaerobic sludge blanket reactor integrated with constructed wetland for treatment of banana winery effluent." Water Practice and Technology 12, no. 3: 667-674.
Researchers on metallic iron (Fe0) for environmental remediation and water treatment are walking in a valley of confusion for 25 years. This valley is characterized by the propagation of different beliefs that have resulted from a partial analysis of the Fe0/H2O system as (1) a reductive chemical reaction was considered an electrochemical one and (2) the mass balance of iron has not been really addressed. The partial analysis in turn has been undermining the scientific method while discouraging any real critical argumentation. This communication re-establishes the complex nature of the Fe0/H2O system while recalling that, finally, proper system analysis and chemical thermodynamics are the most confident ways to solve any conflicting situation in Fe0 environmental remediation.
Susanne Makota; Arnaud I. Nde-Tchoupe; Hezron T. Mwakabona; Raoul Tepong-Tsindé; Chicgoua Noubactep; Achille Nassi; Karoli N. Njau. Metallic iron for water treatment: leaving the valley of confusion. Applied Water Science 2017, 7, 4177 -4196.
AMA StyleSusanne Makota, Arnaud I. Nde-Tchoupe, Hezron T. Mwakabona, Raoul Tepong-Tsindé, Chicgoua Noubactep, Achille Nassi, Karoli N. Njau. Metallic iron for water treatment: leaving the valley of confusion. Applied Water Science. 2017; 7 (8):4177-4196.
Chicago/Turabian StyleSusanne Makota; Arnaud I. Nde-Tchoupe; Hezron T. Mwakabona; Raoul Tepong-Tsindé; Chicgoua Noubactep; Achille Nassi; Karoli N. Njau. 2017. "Metallic iron for water treatment: leaving the valley of confusion." Applied Water Science 7, no. 8: 4177-4196.
Metallic iron (Fe0)-based filtration systems have the potential to significantly contribute to the achievement of the United Nations (UN) Sustainable Development Goals (SDGs) of substantially improving the human condition by 2030 through the provision of clean water. Recent knowledge on Fe0-based safe drinking water filters is addressed herein. They are categorized into two types: Household and community filters. Design criteria are recalled and operational details are given. Scientists are invited to co-develop knowledge enabling the exploitation of the great potential of Fe0 filters for sustainable safe drinking water provision (and sanitation).
Elham Naseri; Arnaud Igor Ndé-Tchoupé; Hezron T. Mwakabona; Charles Péguy Nanseu-Njiki; Chicgoua Noubactep; Karoli N. Njau; Kerstin D. Wydra. Making Fe0-Based Filters a Universal Solution for Safe Drinking Water Provision. Sustainability 2017, 9, 1224 .
AMA StyleElham Naseri, Arnaud Igor Ndé-Tchoupé, Hezron T. Mwakabona, Charles Péguy Nanseu-Njiki, Chicgoua Noubactep, Karoli N. Njau, Kerstin D. Wydra. Making Fe0-Based Filters a Universal Solution for Safe Drinking Water Provision. Sustainability. 2017; 9 (7):1224.
Chicago/Turabian StyleElham Naseri; Arnaud Igor Ndé-Tchoupé; Hezron T. Mwakabona; Charles Péguy Nanseu-Njiki; Chicgoua Noubactep; Karoli N. Njau; Kerstin D. Wydra. 2017. "Making Fe0-Based Filters a Universal Solution for Safe Drinking Water Provision." Sustainability 9, no. 7: 1224.
Around year 1890, the technology of using metallic iron (Fe0) for safe drinking water provision was already established in Europe. The science and technology to manufacture suitable Fe0 materials were known and further developed in this period. Scientists had then developed skills to (i) explore the suitability of individual Fe0 materials (e.g. iron filling, sponge iron) for selected applications, and (ii) establish treatment processes for households and water treatment plants. The recent (1990) discovery of Fe0 as reactive agent for environmental remediation and water treatment has not yet considered this ancient knowledge. In the present work, some key aspects of the ancient knowledge are presented together with some contemporised interpretations, in an attempt to demonstrate the scientific truth contained therein. It appears that the ancient knowledge is an independent validation of the scientific concept that in water treatment (Fe0/H2O system) Fe0 materials are generators of contaminant collectors.
Hezron T. Mwakabona; Arnaud Igor Ndé-Tchoupé; Karoli N. Njau; Chicgoua Noubactep; Kerstin D. Wydra. Metallic iron for safe drinking water provision: Considering a lost knowledge. Water Research 2017, 117, 127 -142.
AMA StyleHezron T. Mwakabona, Arnaud Igor Ndé-Tchoupé, Karoli N. Njau, Chicgoua Noubactep, Kerstin D. Wydra. Metallic iron for safe drinking water provision: Considering a lost knowledge. Water Research. 2017; 117 ():127-142.
Chicago/Turabian StyleHezron T. Mwakabona; Arnaud Igor Ndé-Tchoupé; Karoli N. Njau; Chicgoua Noubactep; Kerstin D. Wydra. 2017. "Metallic iron for safe drinking water provision: Considering a lost knowledge." Water Research 117, no. : 127-142.
Since the realization in the 1930s that elevated fluoride concentrations in drinking water can have detrimental effects on human health, new methods have been progressively developed in order to reduce fluoride to acceptable levels. In the developing world the necessity for filtration media that are both low-cost and sourced from locally available materials has resulted in the widespread use of bone char. Since the early 1990s metallic iron (Fe0) has received widespread use as both an adsorbent and a reducing agent for the removal of a wide range of contaminant species from water. The ion-selectivity of Fe0 is dictated by the positively charged surface of iron (hydr)oxides at circumneutral pH. This suggests that Fe0 could potentially be applied as suitable filter media for the negatively charged fluoride ion. This communication seeks to demonstrate from a theoretical basis and using empirical data from the literature the suitability of Fe0 filters for fluoride removal. The work concludes that Fe0-bearing materials, such as steel wool, hold good promise as low-cost, readily available and highly effective decentralized fluoride treatment materials.
Arnaud Igor Ndé-Tchoupé; Richard A. Crane; Hezron T. Mwakabona; Chicgoua Noubactep; Karoli N. Njau. Technologies for Decentralized Fluoride Removal: Testing Metallic Iron-based Filters. Water 2015, 7, 6750 -6774.
AMA StyleArnaud Igor Ndé-Tchoupé, Richard A. Crane, Hezron T. Mwakabona, Chicgoua Noubactep, Karoli N. Njau. Technologies for Decentralized Fluoride Removal: Testing Metallic Iron-based Filters. Water. 2015; 7 (12):6750-6774.
Chicago/Turabian StyleArnaud Igor Ndé-Tchoupé; Richard A. Crane; Hezron T. Mwakabona; Chicgoua Noubactep; Karoli N. Njau. 2015. "Technologies for Decentralized Fluoride Removal: Testing Metallic Iron-based Filters." Water 7, no. 12: 6750-6774.
To minimize the pollution from municipal solid waste incinerators, the study of operating conditions is imperative. The local design incinerators can be used for high performance combustion and minimize pollutions. The incinerator located at Bagamoyo hospital in Tanzania is used as a pilot for this experiment. The emission and operating conditions shows that the performance of incinerator is at maximum peak of about 70% when the oxygen at exit is about 6.9% and when secondary temperature is between 1073 and 1173K and primary temperature maintained at 673K. The experiment shows that when the primary chamber temperature increases beyond 673K, the secondary temperature decreases this is due to complete combustion at primary chamber which will cause insufficient incomplete gases and therefore limited combustible gases to burn.
Arthur Mngoma Omari; Geoffrey Reuben John; Karoli Nicholas Njau; Peter Lucas Mtui. Operating Conditions of A Locally Made Fixed-Bed Incinerator, a Case Study of Bagamoyo – Tanzania. International Journal of Environmental Monitoring and Analysis 2015, 3, 80 .
AMA StyleArthur Mngoma Omari, Geoffrey Reuben John, Karoli Nicholas Njau, Peter Lucas Mtui. Operating Conditions of A Locally Made Fixed-Bed Incinerator, a Case Study of Bagamoyo – Tanzania. International Journal of Environmental Monitoring and Analysis. 2015; 3 (2):80.
Chicago/Turabian StyleArthur Mngoma Omari; Geoffrey Reuben John; Karoli Nicholas Njau; Peter Lucas Mtui. 2015. "Operating Conditions of A Locally Made Fixed-Bed Incinerator, a Case Study of Bagamoyo – Tanzania." International Journal of Environmental Monitoring and Analysis 3, no. 2: 80.