Browsing by Author "Miraji, Hossein"

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    1-D transport behaviour of emerging contaminants in the unidirectional flowing surface waters of the Msimbazi River
    (College of Natural and Applied Sciences, University of Dar es Salaam, 2020) Miraji, Hossein; Mureithi, Eunice; Othman, Othman C.; Ngassapa, Faustin
    The primary objectives of this investigation of environmental pollution were to assess spatio-temporal concentrations and predictions of transport behaviour of pollutants in aqueous media. In order to attain these goals for the Msimbazi river, the analytical and numerical solutions to the 1-D advection-dispersion equation (ADE) implemented the first-type inlet condition. The MATLAB software was used to solve the analytical equation resulting from the ADE equation. The solution to the ADE model enabled effective prediction of contaminants’spatial distribution within a distance of 200 m from a point source in the direction of flowing water. Among the first and third-types inlet conditions, the first-type had the best exponential concentration prediction with descending concentration gradients between –100 ng/L.m and –0.4 ng/L.m, while beyond it the concentration gradient was merely constant. These findings are the first of this type in our region to the best of our knowledge, and hence a milestone for understanding the transport behaviour of emerging contaminants, and enable estimation of probable pollution-free zones. This study gave results that can form a basis for analytical and public interventions.
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    Analytical perspectives on emerging organic contaminants in the aquatic ecosystem
    (IGI Global, 2020) Miraji, Hossein; Ngassapa, Faustin; Othman, Othman Chande; Eunice, Mureithi
    This chapter introduces readers to the background of emerging contaminants by defining emerging contaminants and telling their history and their corresponding effects. It describes the dynamic properties of emerging contaminants such as advection and dispersion, chemistry, and their reactivity behavior. Lastly, it tells the analytical methodologies on sample preparation such as solid phase extraction and solid-phase micro-extraction, detection and quantification of organic ECs, and it proposes future perspectives of emerging contaminants.
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    Antibiotic-resistant microbial populations in urban receiving waters and wastewaters from Tanzania
    (Elsevier, 2023) Ripanda, Asha Shabani; Rwiza, Mwemezi J.; Nyanza, Elias Charles; Miraji, Hossein; Bih, Numfor Linda; Mzula, Alexanda; Mwega, Elisa; Njau, Karoli N.; Vuai, Said Ali Hamad; Machunda, Revocatus L.
    Antimicrobial resistance against certain medications in the pathogenic microbial community is globally increasing due to the continual discharge and disposal of pharmaceuticals in the environment. The phenomenon resulted in significant antibiotic resistance among several exposed Enterobacteriaceae species, with wastewater treatment plants (WWTPs) and rivers serving as significant reservoirs. Despite antibiotic resistance being a tragedy, particularly in treating diseases by using antibiotics, local and regional studies indicating the severity, resistant species and the molecular level insight into these pathogens are scarce, thus requiring immediate intervention. This study, therefore, investigated wastewater from wastewater treatment ponds and receiving waters for the presence of resistant pathogens through phenotypical and molecular approach screening of their genes. Among the 57 analyzed samples, 18 (67%, n = 27) isolates of Klebsiella spp.., 4 (80%, n = 5) isolates of Proteus spp., 1 (100%, n = 1) of isolated Pseudomonas aeruginosa and 6 (18%, n = 34) of E. coli found were resistant to at least 1 among the tested antibiotics. E. coli had an 83% higher proportion of multi-drug resistance (MDR) than Klebsiella spp.., which had 68.5%, and no MDR was shown by P. aeruginosa isolates. Among the 20 bacterial isolates of antibiotic-resistant genes, showed that E. coli harboured 39%, followed by 22% of Klebsiella spp. Eleven (11) isolates of these 20 (55%) contained sulphonamides resistant genes: Sul 1 (n = 4) and Sul 2 (n = 7). Ten (10) isolates (50%) contained the tetracyclineresistant genes in which 4 isolates showed the Tet A, Tet B – 1 and 5 isolates contained Tet D. β-lactamases (bla CTX-M and bla SHV) were found in 7 isolates (35%). The existence of these antibiotic-resistant species in the urban receiving and wastewater presents a threat of transmission of diseases to humans and animals that are not cured by the existing medications, jeopardizing public health safety.
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    Biotransformation of 1,4-Dioxane by the Use of Bacteria in the Soil
    (Springer Nature Singapore, 2023) Miraji, Hossein; Ripanda, Asha; Bakari, Ramadhani; Sarma, Hemen
    Background: 1,4-Dioxane, also known as dioxane, is a water-miscible synthetic industrial chemical used as a stabilizer for chlorinated solvents and feedstock chemical for a wide range of industrial consumer products. It is a heterocyclic organic ether that, through consumer products and industrial, municipal, and domestic effluents, can get into the environment. Due to its volatility and miscibility, short-term exposure results in irritation of the nose, eyes, and throat, while excessive amounts damage the liver and kidney. Long-term exposure results in carcinogenicity to humans that may associate with death. Statement of problem: 1,4-Dioxane is nonbiodegradable in nature and hence persists in the environmental compartments; some methods such as UV peroxide oxidation, direct UV photolysis, and activated carbon adsorption were reported to be effective in the removal of dioxane in the environment. Yet, their adaptation challenges such as complex matrices, running costs, mass balance, and stoichiometry limitations hinder their efficiency. Finding: Mimicking natural or integrated techniques such as bacteriological transformation of dioxane via aerobic, anaerobic, microcosm, integrated microbial community, and co-metabolic techniques is among the robust eco-friendly technologies against these limitations. Soil matrix offers enormous microbial consortium for nature-based remediation of dioxane with high turnup than single microbial strains. Since bacteriological remediation offers adoptable, flexible, and quick implementation strategies that minimizes the use of synthetic chemicals, its fundamental understanding will be inevitable. Conclusion: Nature-based remediation of dioxane is an undoubtable future since apart from the natural occurrence of soil bacteria responsible for degradation, their natural adaptation flexibility, energy conservation, and release of harmless by-products without formation of secondary synergic harmful contaminants present a relatively affordable technique.
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    Data from the batch adsorption of ciprofloxacin and lamivudine from synthetic solution using jamun seed ( Syzygium cumini ) biochar: Response surface methodology (RSM) optimization
    (Elsevier, 2023) Ripanda, Asha; Rwiza, Mwemezi J.; Nyanza, Elias Charles; Bakari, Ramadhani; Miraji, Hossein; Njau, Karoli N.; Vuai, Said Ali Hamad; Machunda, Revocatus L.
    This dataset expresses the experimental data on the batch adsorption of ciprofloxacin and lamivudine from synthetic solution using jamun seed (JS) (Syzygium cumini) biochar. Independent variables including concentration of pollutants (10-500 ppm), contact time (30–300 min), adsorbent dosage (1-1000 mg), pH (1-14) and adsorbent calcination temperature (250,300, 600 and 750 °C) were studied and optimized using Response Surface Methodology (RSM). Empirical models were developed to predict the maximum removal efficiency of ciprofloxacin and lamivudine, and the results were compared with the experimental data. The removal of polutants was more influenced by concentration, followed by adsorbent dosagage, pH, and contact time and the maximum removal reached 90%.
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    Evaluation of potentiality of traditional hygienic practices for the mitigation of the 2019–2020 Corona Pandemic
    (Wiley, 2022) Ripanda, Asha; Miraji, Hossein; Sule, Khalfani; Nguruwe, Salvatory; Ngumba, Julias; Mtabazi, Geofrey Sahini; Vuai, Saidi Hamad
    The coronavirus outbreak threatens global well-being, costing thousands of lives and an unstable economy. Traditional hand-washing (HaWa) with clean water and hand-washing sanitizers (HaWaSas) are among WHO recommended practices against the outbreaks. HaWaSa and HaWa lacked proper quality monitoring evaluation that may pose health risks. The current study investigates the potential of traditional hygienic practices adopted to mitigate the 2019–2020 Pandemic. It involved assessing the effectiveness of 15 HaWaSa collected from the Dodoma market. Thirty volunteered participants were subjected to different hygienic practices involving HaWa and HaWaSa. The obtained hand-swabbed samples were subjected to the streak plate technique for inoculation, followed by counting colonies. The results revealed that, among the collected HaWaSa brands, only 33.3% were certified by the Tanzania Bureau of Standards (TBS). In the setting under no hand-wash, each client had a different number of colony counts. HaWa did not eliminate all colonies since water acted as a secondary source while only one sanitizer proved effective. The p-values obtained in either setting were greater than 0.05, indicating that each variable was independent. Despite global awareness and fighting against the Coronavirus Disease 2019 (Covid-19) outbreak, quality monitoring of all diagnostic tools, preventive HaWaSa, and related drugs should be prioritized for human safeguard.
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    Quantitative investigation of potential contaminants of emerging concern in the water: a focus at Swaswa wastewater stabilization ponds in Dodoma city
    (National Information and Documentation Center (NIDOC), 2019) Makokola, Sikudhani K.; Ripanda, A.S.; Miraji, Hossein
    Effluents released from wastewater stabilization ponds are re-used for irrigation while sludge is directly applied to agricultural lands as potential fertilizer. However, some treatment schemes are less efficient on the treatment, and not designed for removal of contaminants of emerging concern (CEC). Thus, the current study investigated the occurrence of CEC and physicochemical characteristics of Swaswa wastewater stabilization ponds (SWWSP). Sample partitioning followed by full scan mode GC/MS analysis for screening of CEC was adapted. It was observed that both influent and effluent from SWWSP had a significant amount of CEC such as metronidazole in the range of 0.065-0.104 ppm. It was further observed that physicochemical analysis before and after partition had insignificant differences among EC, salinity, pH, ammonium, and TDS. Nevertheless, turbidity and DO were significantly affected by the partitioning process. The presence of metronidazole poses unclear environmental threat that requires immediate intervention since this chemical and other CEC have no local and international guidelines and do not fall under routine monitoring activities.
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    Removal of lamivudine from synthetic solution using jamun seed (Syzygium cumini) biochar adsorbent
    (Elsevier, 2023) Ripanda, Asha; Rwiza, Mwemezi J.; Nyanza, Elias Charles; Bakari, Ramadhani; Miraji, Hossein; Njau, Karoli N.; Vuai, Said Ali Hamad; Machunda, Revocatus L.
    Antiviral drugs such as lamivudine have been globally identified in the environment and marked as emerging pollutants of concern due to their bioactive extremity. Following therapeutic uses, approximately 70% of the oral dose of lamivudine is eliminated renally as the parent drug. Concerns has been raised for neighbouring aquatic bodies due to effluent produced from production plants containing high concentrations of antiviral drugs. Antiviral drugs, such as lamivudine, are extremely bioactive, prompting interest in their urgent removal from the environment. The purpose of the present study was to optimize the removal of lamivudine from the synthetic solution using jamun seed (JS) (Syzygium cumini) biochar. The influence of sorption parameters such as pH, lamivudine concentration, adsorbent dosage, contact time, and calcination temperatures on the removal of lamivudine was investigated and optimized using a response surface methodology (SRM) based on optimal design. The results indicated that, a quadratic model best fits data with a model regression coefficient R2, adjusted R2, and predicted R2 of 0.9934, 0.9761 and 0.8340, respectively. The JS biochar calcined at 750°C, at pH 8, initial lamivudine concentration of 10 ppm and contact time of 30 min indicated a maximum experimental removal efficiency of 84.9%. The residual standard error (RSE) value was 3.5% implying that the model was reliable. Isotherm data for the adsorption of lamivudine on JS biochar followed the Freundlich isotherm, with an R2 value of 0.9977 while R2 for the modified Langmuir model was 0.9852. These findings indicated that JS biochar is potentially useful for removal of lamivudine, and other organics from contaminated water and wastewater effluents. Therefore, this study presents an environmentally friendly remedy against lamivudine for a healthier ecology
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    Removal of lamivudine from synthetic solution using jamun seed (Syzygium cumini) biochar adsorbent
    (Elsevier BV, 2023) Ripanda, Asha; Rwiza, Mwemezi J.; Nyanza, Elias Charles; Bakari, Ramadhani; Miraji, Hossein; Njau, Karoli N.; Vuai, Said Ali Hamad; Machunda, Revocatus L.
    Antiviral drugs such as lamivudine have been globally identified in the environment and marked as emerging pollutants of concern due to their bioactive extremity. Following therapeutic uses, approximately 70% of the oral dose of lamivudine is eliminated renally as the parent drug. Concerns has been raised for neighbouring aquatic bodies due to effluent produced from production plants containing high concentrations of antiviral drugs. Antiviral drugs, such as lamivudine, are extremely bioactive, prompting interest in their urgent removal from the environment. The purpose of the present study was to optimize the removal of lamivudine from the synthetic solution using jamun seed (JS) (Syzygium cumini) biochar. The influence of sorption parameters such as pH, lamivudine concentration, adsorbent dosage, contact time, and calcination temperatures on the removal of lamivudine was investigated and optimized using a response surface methodology (SRM) based on optimal design. The results indicated that, a quadratic model best fits data with a model regression coefficient R2, adjusted R2, and predicted R2 of 0.9934, 0.9761 and 0.8340, respectively. The JS biochar calcined at 750 °C, at pH 8, initial lamivudine concentration of 10 ppm and contact time of 30 min indicated a maximum experimental removal efficiency of 84.9%. The residual standard error (RSE) value was 3.5% implying that the model was reliable. Isotherm data for the adsorption of lamivudine on JS biochar followed the Freundlich isotherm, with an R2 value of 0.9977 while R2 for the modified Langmuir model was 0.9852. These findings indicated that JS biochar is potentially useful for removal of lamivudine, and other organics from contaminated water and wastewater effluents. Therefore, this study presents an environmentally friendly remedy against lamivudine for a healthier ecology.