NULIR
The National University of Lesotho Institutional Repository (NULIR) is a digital archive that collects, preserves, and provides open access to the scholarly and intellectual output of the University.
Recent Submissions
Exploring the use of process writing approach in enhancing narrative writing skills among Grade 9 English Language learners in one Secondary school in Leribe
(National University of Lesotho, 2026) Mofolo, Tsooana; Mahao, Mahao; Matee, Lihotetso Gloria
Narrative writing remains a predominant challenge impeding learners’ performance in English language classrooms within secondary school contexts. This study investigated the application of the process writing approach as a pedagogical strategy for enhancing narrative writing skills among Grade 9 English language learners at a selected secondary school in Leribe. The research was underpinned by Vygotsky’s Sociocultural Theory (1978), which foregrounds the critical role of social interaction, collaboration and scaffolding in the learning process. A mixed-methods approach was adopted, employing a single-group pretest-posttest experimental design; supplemented by qualitative interviews. The study comprised 45 Grade 9 English language learners, purposively selected from one secondary school in Leribe. Quantitative data were gathered through pretest and posttest writing tasks, whereas qualitative data were elicited through semi-structured interviews. Quantitative data were analysed using SPSS version 26, while qualitative data underwent thematic analysis. The findings demonstrated a statistically significant improvement in learners’ narrative writing skills following the implementation of the process writing approach. Furthermore, learners articulated positive perceptions of the approach, indicating that it facilitated enhanced planning, revision, idea organisation and writing confidence. The study concludes that the process writing approach constitutes an effective pedagogical intervention for improving learners’ narrative writing abilities. Accordingly, it is recommended that English language teachers integrate the process writing approach into writing instruction to foster narrative writing competence among secondary school learners in Lesotho.
Effect of waste disposal on nitrate and phosphate levels in Raleting Dam, Lesotho
(National University of Lesotho, 2025) Moeti, Lepekola; Mahamo, Tebello
Surface water quality in urban areas is consistently declining due to the indiscriminate disposal of
both liquid and solid wastes. Identifying waste sources and factors increasing nitrate and phosphate
levels in potable water bodies is crucial for water resource managers to mitigate nutrient pollution.
This study evaluates the effect of waste disposal on nitrate and phosphate levels in Raleting Dam,
located in Mafeteng, Lesotho. Fifty-four water samples were collected from nine sampling
locations from March to May 2025. All samples were analysed using a HACH DR6000
spectrophotometer. The results indicated that domestic waste and industrial effluents are the
primary contributors of nitrate and phosphate in this reservoir, respectively. Results revealed that
all water samples had nitrate concentrations that are within the WHO acceptable contamination
threshold of 50 mg/L, with an average value of (4.200 ± 1.083) mg/L. Results also revealed that
all samples had phosphate levels exceeding the WHO acceptable contamination threshold of 0.03
mg/L, with an average value of (1.620 ± 0.740) mg/L. Higher nitrate concentration levels were
exhibited during the wet season compared to the dry season, yielding mean values of 1.987 mg/L
and 1.694 mg/L, respectively. In contrast, higher phosphate concentrations were observed during
the dry season, compared to the wet season, yielding the mean values of (1.026 ± 0.114) mg/L and
(1.003 ± 0.081) mg/L, respectively. There is, however, no positive correlation between nitrate and
phosphate levels, hence suggesting a weak relationship between these two parameters.
Historically, nitrate and phosphate levels revealed a gradual increase over time. Extensive
investigations are further required around the identified pollution hotspots to ascertain the
particular sources and facilitate the implementation of corrective actions. Findings from this study
raise awareness among water resource managers and policymakers about the significant harm caused by the indiscriminate disposal of waste in this reservoir. The study can therefore serve as a
basis from which local authorities and policymakers can formulate and implement waste
management strategies in this area. Future research should explore public perceptions of illegal
dumping and involve larger sample sizes over different periods for accurate analysis. Prioritizing
physico-chemical parameters in future studies is essential for assessing water quality for domestic
use.
Solar water purification system for rural areas
(National University of Lesotho, 2025) Makebe, Rethabile; Jonathan, Enock; Kao, Moruti
This dissertation examines the design, efficacy, and viability of a hybrid solar photovoltaic-thermal (PVT) and ultraviolet (UV) water purification system specifically developed for rural Lesotho, featuring a case study in the Mohale Basin. The system incorporates thermal energy capture by the solar PVT array to preheat feedwater before reverse osmosis (RO) treatment, hence improving membrane efficiency and minimizing fouling hazards. The electricity produced by the PVT array energizes UV disinfection devices and water pumps, while battery storage guarantees continuous operation under low solar irradiance circumstances.
Two optimized setups, that is, 5.2 kWp and 14.4 kWp were simulated by PVsyst, underpinned by mathematical modelling and validated against DuPont WAVE software. The 14.4 kWp configuration exhibits enhanced energy reliability with feedwater preheating to 40 °C, recovery rates of 60%, and specific energy consumption as low as 1.06 kWh/m³. Comparative evaluations solar PV and solar PVT RO demonstrate that the incorporation of PVT preheating with dual-stage RO markedly decreases operating pressures and enhances water quality. Analysis indicated that the smaller 5.2 kWp system, despite its reduced initial expenditure, yields water at a higher Levelized Cost of Water (LCOW) of USD 1.25/m³. The larger 14.4 kWp system on the other hand attained a lower LCOW of USD 0.75/m³, illustrating the benefits of economies of scale in hybrid PVT-RO configurations.
This work demonstrates the viability of scalable solar-driven water purification systems for offgrid rural Lesotho, with implications for sustainable development and climate adaptation, providing a viable approach to furthering Sustainable Development Goals 6 (Clean Water and Sanitation) and 7 (Affordable and Clean Energy) in Lesotho.
Integration of solar heating systems in the textile industry
(National University of Lesotho, 2024) Leseeka, Litheba Catherine
Currently, fossil fuels are the mostly used source of thermal energy in the industrial sector in Lesotho. They provide the necessary heat for different industrial processes across a range of temperatures. Within the sector, the textile industry is a significant consumer of thermal energy, particularly for the wetting processes that require large amounts of hot water. As global concerns about climate change and global warming intensify, industries are required to reduce their carbon footprint and transition to cleaner and sustainable energy sources. This study investigated the techno-economic viability of integrating solar water heating systems at the Vishan Clothing Laundry facility in Maseru, Lesotho, using T*SOL simulation software. The study focused on three main points: solar thermal system design, performance analysis and evaluating the economic aspects of the proposed system. To determine the most efficient system for meeting the laundry’s hot water needs, six separate simulations were conducted for a comprehensive comparative analysis. From the simulations, the optimally designed system consists of Dimas SA RADIANT RSV 25 flat-plate collectors at 30° inclination angle with a collector area of 1,980 m2 and a storage tank with a capacity of 130 m3. This configuration achieves an efficiency of 54%, and a solar fraction of 89%, indicating a significant contribution from solar energy to the overall hot water production. The economic analysis under two different financing approaches shows that the system is economically viable. The proposed system under equity financing has a capital return time of 7 years, a positive net present value (NPV) of M 13,981,755, an internal rate of return (IRR) at 16.88% and cost of solar energy at M 0.831/kWh. Under equity-debt financing, the proposed system has a capital return time of
7.9 years, and amortization period of 10.3 years, a positive NPV of M 12,983,854, an IRR at 18.78% and cost of solar energy at M 0.872/kWh. These financial indicators demonstrate the economic feasibility and potential profitability of integrating solar heating systems in the textile industry. The study further highlights the need for further research to refine the system design and improve its performance. Most importantly, the study emphasizes the necessity of conducting in-depth energy audits to accurately determine the thermal energy demand of the facility. Such audits can probably provide more precise data, ensuring that the designed system can adequately meet the thermal energy demand of the laundry facility.
Formulating short-term electricity demand forecasting for Lesotho
(National University of Lesotho, 2020) Lefela, Lereko; Thamae, Leboli Zak
Electricity demand forecasting is an important process in the planning and operation of the electricity industry. Providing uninterrupted energy to consumers requires electricity demand to be predicted accurately. This study utilizes ABB Nostradamus short-term demand forecasting software, which accepts historical demand data, days of the week, time of the year and Lesotho public holidays for electricity demand forecasting. It produced day-ahead, week-ahead and hourahead electricity demand forecasting results with 3.06%, 4.06% and 5.09% accuracy. These MAPE results are close to or within the acceptable 5% accuracy for short-term demand forecasting, and provide crucial confidence levels for LEC to engage in power pool trading in the SAPP market for optimal power procurement.
LEC utilizes bilateral agreements with LHDA, Eskom and EDM to supply the electricity demand. During the high demand season, bilateral imports from Eskom and EDM costs LEC around 3.27 Million US Dollars (M49 Million) which is twice the money incurred (1.60 Million US Dollars (M24 Million)) during the low demand season. Compared to the average SAPP
DAM, IDM and FPM-W prices, Eskom’s 20 USc/kWh peak cost is higher than SAPP’s 12 USc/kWh DAM and IDM, and 13 USc/kWh FPM-W peak charges. Again, EDM’s 4 USc/kWh off-peak cost is higher than SAPP’s 3 USc/ kWh DAM, IDM and FPM-W off-peak charges. The study therefore recommends bilateral contracts use to meet intermediate demand of around 103 MW. For demand above 103 MW, utilizing SAPP market can assist to reduce bulk purchases costs.