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Integration of the energy recovery step in municipal wastewater treatment chain: a case study of Moshi municipality, Tanzania
Get PDFA Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of
Master's of Environmental Science and Engineering of the Nelson Mandela African
Institution of Science and Technology (NM-AIST)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 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 oC and 37 oC. The results showed substrate mixture containing 6% of SCM
and total solids (TS) of 7.52% yielded 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 hence needed careful adjustment using 2M of NaOH
solution. This study recommends substrate mixture containing SCM (2%) and TS (4.34%)
having biogas production (4.97 L/L of modified substrate) for energy recovering from
MWWTPS, since is 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 produce up to 1.8 GWh
and 8193 GJ per annum. The study concluded that biogas is among of the future fuel if the
modern technology on anaerobic digestion is functional. Also the use of combined heat and
power (CHP) engine for the conversion of biogas to heat and electrical energy increases the
energy value of the wastewater.
(Keywords: Anaerobic digestion, Biogas, Municipal wastewater, Sugarcane molasses
LPG-Fueled Vehicles: An Overview of Technology and Market Trend
Get PDFThis research article published by Automotive Experiences Vol. 3 No.1, 2020This article presents an overview of the technology status and market trends of LPG-fueled
vehicles through the literature approach to re-evaluate their future. In the review, it is
discovered that LPG vehicles are globally increasing, though with a concentration in some
countries. Of the 25 countries included in the World LPG Association (WLPGA) annual report
2018, Turkey, Poland, India, Ukraine, and Mexico are the countries with the best LPG vehicle
trends in average of 23%. Meanwhile, Australia, Japan, South Korea, United Kingdom, the
Netherlands, France, and Germany with a long history of implementing LPG as an alternative
fuel has experienced a decline in the 2013-2017 period by 17%. This was allegedly due to the
penetration of diesel-fueled vehicles over the last ten years. Moreover, developed countries
experiencing decline have succeeded in developing electric-based vehicles such as Hybrid
Electric Vehicle (HEV), Plug-in hybrid electric vehicle (PHEV), Battery Electric Vehicles (BEV),
and Fuel Cell Electric Vehicles (FCEV) due to stringent demands for emission standards
Molecular basis of susceptibility to Newcastle disease virus challenge in exotic and local Tanzanian chicken
Get PDFA Thesis Submitted in Partial Fulfilment of the Requirements for the Degree of Doctor
of Philosophy in Life Sciences of the Nelson Mandela African Institution of Science and
Technology, Arusha, TanzaniaThis research aimed to investigate genetic mechanisms of susceptibility to Newcastle disease
virus (NDV) in exotic and local Tanzanian chicken. In the first experiment kuroiler, broiler
and local Tanzanian chickens were vaccinated with live La Sota Newcastle disease (ND)
vaccine, and body weight gain and antibody responses were used as phenotypes to evaluate
chicken susceptibility to NDV. Results showed higher (P < 0.05) antibody titres in kuroilers
(3.81 ± 0.06) as compared to local chickens (3.73 ± 0.07) and broilers (3.53±0.06) at day 10
post-vaccination. However, antibody titres were not different (P > 0.05) between kuroilers
and local Tanzania chickens at day 21 post-vaccination. Although results showed differences
between vaccinated and control groups, the results could not give clear cut differences on
variations in susceptibility, probably because a less virulent strain of NDV was used and the
housing environment might have created some confounding variables. Therefore, in the
second experiment virulent NDV and chicken embryo model were used to investigate
chickens variation in susceptibility to NDV where time of death post-challenge was used as a
phenotype. A total of 355 (87 Sasso, 129 kuroiler and 139 local) 16-day-old chicken embryos
were challenged with virulent NDV, and death time was recorded post-challenge. Candidate
gene and selective genotyping approaches were deployed, and therefore, chicken embryos
from high (15%) and less (15%) susceptible cohorts were genotyped for selected genes
(myxovirus resistance gene (Mx) and LEI0258). As expected, chicken embryos survival time
was highly variable within a breed. Furthermore, it was demonstrated that chicken Mx gene
G2032A genotypes (AA, AG, and GG) were associated (P < 0.05) with susceptibility.
Interestingly, for the first time, findings demonstrated an association between chicken Mx
gene promoter polymorphisms and chicken embryos susceptibility to virulent NDV.
Specifically, SNP4 G>A mutation located within IFN-stimulating response element was
associated (LR: 6.97, P = 0.03) with susceptibility. Also, haplotype ACGC was associated
(OR: 9.8, 95% CI: 1.06 – 79.43, P = 0.042) with the same trait, and had a protective effect.
The present findings are very useful in breeding programs designed to develop chicken
genotypes, which are less susceptible to NDV
Long-lasting insecticidal nets retain bio-efficacy after 5 years of storage: implications for malaria control programmes
Get PDFThis research article published by Springer Nature, 2020Background: Long-lasting insecticidal nets (LLINs) are the most sustainable and efective malaria control tool currently available. Global targets are for 80% of the population living in malaria endemic areas to have access to (own)
and use a LLIN. However, current access to LLINs in endemic areas is 56% due to system inefciencies and budget
limitations. Thus, cost-efective approaches to maximize access to efective LLINs in endemic areas are required. This
study evaluated whether LLINs that had been stored for 5 years under manufacturer’s recommended conditions may
be optimally efective against Anopheles mosquitoes, to inform malaria control programmes and governments on the
periods over which LLINs may be stored between distributions, in an efort to maximize use of available LLINs.
Methods: Standard World Health Organization (WHO) bioassays (cone and tunnel test) were used to evaluate the
bio-efcacy and wash resistance of Olyset® and DawaPlus® 2.0 (rebranded Tsara® Soft) LLINs after 5 years of storage
at 25 °C to 33.4 °C and 40% to 100% relative humidity. In addition, a small scale Ifakara Ambient Chamber test (I-ACT)
was conducted to compare the bio-efcacy of one long stored LLINs to one new LLIN of the same brand, washed
or unwashed. LLINs were evaluated using laboratory reared fully susceptible Anopheles gambiae sensu stricto (s.s.)
(Ifakara strain) and pyrethroid resistant Anopheles arabiensis (Kingani strain).
Results: After 5 years of storage, both unwashed and washed, Olyset® and DawaPlus® 2.0 (Tsara® Soft) LLINs passed
WHO bio-efcacy criteria on knockdown (KD60) ≥95%, 24-h mortality ≥80% and ≥90% blood-feeding inhibition in
WHO assays against susceptible An. gambiae s.s. DawaPlus® 2.0 LLINs also passed combined WHO bioassay criteria against resistant An. arabiensis. Confrmatory I-ACT tests using whole nets demonstrated that long-stored LLINs
showed higher efcacy than new LLINs on both feeding inhibition and mortality endpoints against resistant strains.
Conclusions: Even after long-term storage of around 5 years, both Olyset® and DawaPlus® 2.0 LLINs remain efcacious against susceptible Anopheles mosquitoes at optimal storage range of 25 °C to 33.4 °C for temperature and 40%
to 100% relative humidity measured by standard WHO methods. DawaPlus® 2.0 (Tsara® Soft) remained efcacious
against resistant strain
Demand-SideManagement of Solar Microgrid Operation: Effect of Time-of-Use Pricing and Incentives
Get PDFThis research article published by Hindawi, 2020Over 17% of the world’s population lack access to electricity, the majority being in rural areas of sub-Saharan Africa and South
Asia. Microgrid technologies are a promising solution towards rural and remote area electrification; however, ever-increasing
electricity demand remains a big challenge leading to pronounced power outages. Demand-side management is an indispensable
tool towards addressing the challenges. is paper employs a mathematical model based on incentives and time-of-use rates to
simulate daily power usage pattern of residential customers using data collected from an isolated village Ngurdoto solar microgrid,
Arusha, Tanzania. Customer responsiveness on the increase in price was evaluated based on the concept of price elasticity of
demand. Using two demand response strategies, namely, load shifting (LS) and scheduled load reduction (SLR), the results reveal
that LS can achieve up to 4.87% energy-saving, 19.23% cost-saving, and about 31% and 19% peak reduction and power factor
improvement, respectively. SLR method resulted in about 19% energy-saving, 49% cost-saving, and 24% power factor improvement. us, the results presented in this study may lead to a more efficient and stable system than the current state in
developing countries’ utilit
How Can We Represent Seasonal Land Use Dynamics in SWAT and SWAT+ Models for African Cultivated Catchments?
Get PDFThis research article published by MDPI, 2020In SWAT and SWAT+ models, the variations in hydrological processes are represented by Hydrological Response Units (HRUs). In the default models, agricultural land cover is represented by a single growing cycle. However, agricultural land use, especially in African cultivated catchments, typically consists of several cropping seasons, following dry and wet seasonal patterns, and are hence incorrectly represented in SWAT and SWAT+ default models. In this paper, we propose a procedure to incorporate agricultural seasonal land-use dynamics by (1) mapping land-use trajectories instead of static land-cover maps and (2) linking these trajectories to agricultural management settings. This approach was tested in SWAT and SWAT+ models of Usa catchment in Tanzania that is intensively cultivated by implementing dominant dynamic trajectories. Our results were evaluated with remote-sensing observations for Leaf Area Index (LAI), which showed that a single growing cycle did not well represent vegetation dynamics. A better agreement was obtained after implementing seasonal land-use dynamics for cultivated HRUs. It was concluded that the representation of seasonal land-use dynamics through trajectory implementation can lead to improved temporal patterns of LAI in default models. The SWAT+ model had higher flexibility in representing agricultural practices, using decision tables, and by being able to represent mixed cropping cultivations
Intelligent handover decision scheme using double deep reinforcement learning
Get PDFThis research article published by Elsevier B.V., Volume 42, October 2020Handovers (HOs) have been envisioned to be more challenging in 5G networks due to the inclusion of millimetre wave (mm-wave) frequencies, resulting in more intense base station (BS) deployments. This, by its turn, increases the number of HOs taken due to smaller footprints of mm-wave BSs thereby making HO management a more crucial task as reduced quality of service (QoS) and quality of experience (QoE) along with higher signalling overhead are more likely with the growing number of HOs. In this paper, we propose an offline scheme based on double deep reinforcement learning (DDRL) to minimize the frequency of HOs in mm-wave networks, which subsequently mitigates the adverse QoS. Due to continuous and substantial state spaces arising from the inherent characteristics of the considered 5G environment, DDRL is preferred over conventional -learning algorithm. Furthermore, in order to alleviate the negative impacts of online learning policies in terms of computational costs, an offline learning framework is adopted in this study, a known trajectory is considered in a simulation environment while ray-tracing is used to estimate channel characteristics. The number of HO occurrence during the trajectory and the system throughput are taken as performance metrics. The results obtained reveal that the proposed method largely outperform conventional and other artificial intelligence (AI)-based models
Monitoring spread of epidemic diseases by using clinical data from multiple hospitals: a data warehouse approach
Get PDFA Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of
Master’s in Information and Communication Science and Engineering of the
Nelson Mandela African Institution of Science and TechnologyMany countries apply data science techniques to enhance their health sectors and the
surveillance of diseases. The success of the innovations lies on the availability and quality of
datasets to be analyzed. In Tanzania, while different Hospital Management Information Systems
(HoMIS) like the Government of Tanzania Hospital Management Information System (GoTHoMIS)
are
installed
in
various
hospitals,
the
data
stored
in
the
systems
are
not
integrated.
This
causes
unavailability of high quality, timely, anonymous, harmonized, and integrated datasets
that can be shared and exhaustively analyzed for epidemic diseases surveillance. This study
intended to develop a data warehouse to host patients’ demographic and clinical particulars
essential for epidemic diseases surveillance from a multi-node GoT-HoMIS, and yield an
integrated dataset that can be used for epidemic diseases surveillance.
Interviews were conducted in three strategic health facilities and the Ministry responsible for
Health in Tanzania. Documents were reviewed, and observation done on the patient’s
registration process in the GoT-HoMIS. Thereafter, a data warehouse was developed to run
under MariaDB database server, and using Hypertext Preprocessor an Extract, Transform, and
Load (ETL) module was developed. The ETL module was deployed at six health facilities, and
the resulting integrated dataset of 152 104 facts was visualized by using FusionCharts libraries.
The study demonstrates a novel means to extract data straight from the GoT-HoMIS nodes,
which has the potential to make available and provide timely data and integrated reports for
decision-making on epidemics. By scaling the innovation to other health facilities, epidemics
surveillance can be significantly enhanced
Cryptogamic Packed Biofilter as Potential Adsorbent for CO2, NH3, and H2S Impurities from Biogas
Get PDFThis research article published by Hindawi, 2020The presence of elevated concentrations of carbon dioxide, hydrogen sulfide, ammonia, and trace impurities in biogas affect its caloric value as well as causes corrosion and is extremely toxic. There are various methods in existence for removal of these impurities, but most are chemically based and expensive and are limited in use. In our work, cryptogams (moss) integrated with soil and biochar packed in a filter have been employed for simultaneous removal of CO2, H2S, and NH3, from biogas. Different soil types rich in metallic oxides at different masses of 100 g, 150 g, and 200 g with a fixed mass of moss and biochar were tested in an on-site experiment to determine the removal efficiency (RE) and sorption capacity (SC). The adsorption dynamics of the filters were investigated at two flow rates, 80 ml/min and 100 ml/min, by determining removal efficiency. For the contribution of each substrate, sorption capacity and breakthrough time were determined by considering 5 g of each substrate that made up the filter. The soils with a high content of extractable cations showed excellent adsorption capacity for H2S by about 20 g S/100 g, which was higher than other adsorbents tested. It was found that integrated biofilter made up of bed arrangement of the soil, biochar, and moss plant improved the quality of biogas with SC of 11 g S and RE of 93% for H2S, 72% for NH3, and 68% for CO2
Electrochemical Sensing Fabricated with TaO Nanoparticle-Electrochemically Reduced Graphene Oxide Nanocomposite for the Detection of Oxytetracycline.
No full textThis Research Article published by MDPI, 2020A novel tantalum pentoxide nanoparticle-electrochemically reduced graphene oxide nanocomposite-modified glassy carbon electrode (TaO-ErGO/GCE) was developed for the detection of oxytetracycline in milk. The composition, structure and morphology of GO, TaO, and TaO-ErGO were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Oxytetracycline electrochemical behavior on the bare GCE, GO/GCE, ErGO/GCE, and TaO-ErGO/GCE was studied by cyclic voltammetry. The voltammetric conditions (including scan rate, pH, deposition potential, and deposition time) were systematically optimized. With the spacious electrochemical active area, the TaO-ErGO/GCE showed a great magnification of the oxidation signal of oxytetracycline, while that of the other electrodes (GCE, GO/GCE, ErGO/GCE) could not reach the same level. Under the optimum conditions, the currents were proportional to the oxytetracycline concentration in the range from 0.2 to 10 μM, and a low detection limit of 0.095 μM (S/N = 3) was detectable. Moreover, the proposed TaO-ErGO/GCE performed practically with satisfactory results. The preparation of TaO-ErGO/GCE in the current work provides a minor outlook of detecting trace oxytetracycline in milk