Journal of Engineering in Agriculture and the Environment
The Journal of Engineering in Agriculture and the Environment,JEAE, is published by the Kenya Society of Environmental, Biological and Agricultural Engineers, KeSEBAE, as an international forum for the publication of basic and applied research in engineering for the environment, agriculture and biology-based production and processing industries.
Kenya Society of Environmental, Biological and Agricultural Engineers
Effects of Point Source Pollution on Water Quality: Case of Athi River, Kenya
Water is the most important natural resource for human, plant and animal survival. Surface water quality has deteriorated resulting from anthropogenic activities. Research determined effects of wastewater effluent from a meat processing plant on Athi river water quality. Physical parameters including Temperature, Dissolved Oxygen (DO), Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD), pH and Turbidity were analysed for dry and wet seasons. Analysis showed a level of increase in pollution of Athi River water downstream during dry season. In both seasons, COD, BOD5, pH and Turbidity increased from sampling point SP1 to SP3. There was noticeable reduction for BOD5 and COD at SP4 indicating ability of the river to self-purify. DO showed reduced amounts from point SP1 to SP4. The results showed untreated wastewater released to Athi River influenced its quality. Therefore, there is need to treat wastewater to the required standard before it is released to reduce the negative impacts.
Copyright (c) 2026 Sharon Kimatui, Wesley Kirui https://creativecommons.org/licenses/by/4.0
Environmental Science Training in Eastern Africa Universities: Constraints and Opportunities for Sustaining Knowledge Systems
Eastern Africa stands at a critical crossroad where environmental degradation, biodiversity loss, and pollution are intensifying climate vulnerability and deepening interconnected challenges such as food and nutrition insecurity, poverty, conflict, and public health risks. In this context, environmental science education is not merely an academic pursuit, but rather, it’s a strategic foundation for sustainable development across the region. This study presents a regional landscape analysis of environmental science training using a mixed-method evaluation of 42 academic programmes across 30 universities in Kenya, Uganda, Tanzania, Rwanda, and Ethiopia, complemented by insights from interviews with 30 faculty leaders. The findings reveal a sector struggling for relevance and impact, yet constrained by structural and resource limitations. Teaching capacity remains stretched with 57% of institutions operating as student: staff ratios between 20:1 and 40:1 which is well above global benchmarks – hence limiting meaningful mentorship, experiential learning, and research productivity. Infrastructure gaps are equally significant where fewer than 40% of programmes report adequate laboratory facilities, less than one-third have sufficient field equipment or reliable transport, and the post-pandemic transition to digital learning continues to be undermined by weak technological systems. Curriculum relevance also emerges as a pressing concern. While environmental challenges are increasingly localized, 70% of programmes rely on outdated learning materials. Indigenous and community knowledge systems are incorporated in only 35% of the curricula, and formal industry-linked internships exists in just 28% of programmes essentially leaving many graduated insufficiently prepared for practices oriented environmental problem solving. Although 62% of the programmes benefits from PhD qualified faculty, persistent brain drain threatens institutional continuity and leadership. Encouragingly, nearly 40% of institutions are currently undertaking curriculum reforms and strengthening inter-university collaboration. The study underscores that advancing sustainable development in Eastern Africa will require more than incremental improvements. It calls for systematic transformation through pedagogical innovations, strategic investment in learning infrastructure, and stronger partnership between universities, industry, and policy actors to align environmental science education with the regions urgent socio-ecological realities.
Copyright (c) 2026 https://creativecommons.org/licenses/by/4.0
Examining the Design and Processes at Matisi Municipal Water Treatment Works in Nzoia Towards Mitigation of Residual Turbidity
Turbidity is an important physical characteristic of water that is often due to high sediment flow, making it a critical factor in municipal water treatment. If not adequately reduced, turbidity causes treated water to have an unattractive cloudy appearance. The aim of the study was to assess the design and processes of Nzoia Water Services Company Limited (NZOWASCO) in Bungoma County, Kenya, to identify system weaknesses and recommend optimal methods for mitigating the adverse effects of high turbidity in the river. The study examined the flow characteristics of River Kuywa, the water source for Matisi Municipal Water Treatment Works, and the sediment load present during extreme conditions. It assessed water quality during these periods and evaluated the efficiency of the infrastructure of the Plant. Plant visits, data collection through sampling, laboratory testing, and a plant design assessment were conducted to identify significant weaknesses that need to be addressed to optimize turbidity removal processes. It was found that during extreme rainfall periods, the abstraction weir, which helps in sediment settling, is ineffective, as depicted by elevated raw water turbidity of 6961.67 NTU compared to 179 NTU measured during normal river flows. It was also deduced that flooding in River Kuywa causes increased turbulence, leading to a sediment-water mixture that flows into the sump where pumps are located. Finally, it was concluded that the absence of a pretreatment facility, essential for reducing sediment load in the water, is a significant issue.
Physical Properties of Roselle Seeds and Other Related Seeds Relevant to the Design of Seed Planters: A Review
Roselle plant (Hibiscus sabdariffa L.) is one of the important vegetables in which almost all parts of the plant are essential sources of food, raw materials used in many industries. To facilitate modern-day planting operations of Roselle seeds for bountiful crop production, planters could be used, just like any other seed. These planters are designed based on some physical properties of the seeds. In this review paper, some physical properties of Roselle seeds and other related seeds were gathered and examined because they are relevant in the perfect development of the seed planter. Keywords: Roselle seeds, physical and mechanical properties, design, seed planters
Assessing The Impact of Government Approved Dumpsites on Agricultural Soils in Ibadan, Nigeria and The Effect of Its Contaminant on The Production of Crop Growth
The rapid expansion of urbanization and industrial activities in Ibadan, Nigeria, has led to the proliferation of dump sites, posing significant challenges to the environment and agricultural practices. A significant amount of elements and organic materials in leachates from solid waste can exceed the needs for crop production and environmental sustainability, potentially enhancing soil properties like moisture and alkalinity. In Ibadan, Nigeria, farmers utilize solid waste as compost to enrich soils, but there are concerns regarding contaminant transfer to crops, which may affect productivity and human health. This study aims at assessing the impact of dump sites on agricultural soils in Ibadan by examining soil contamination implications on crop (okra) productivity. Through soil sampling and analysis, the study evaluates key physio-chemical properties, including pH, organic matter content, nutrient availability, and heavy metal concentrations. The findings reveal that soils from the Lapite dumpsite provide the best conditions for plant growth compared with samples obtained from other dumpsites, showing lower pH of 6.23 and higher organic matter levels of 3.82%. In contrast, soils from Abaeku and Ajakanga exhibited poor fertility and higher contamination, resulting in 12% reduction in the crop yields. The results indicated that high levels of contaminants in these soils negatively impact nutrient absorption and hinder agricultural productivity, posing potential health risks for consumers. Okra plants cultivated in contaminated soils exhibited 2% fewer leaves, and 2% thinner stems, which further demonstrates the detrimental effects on agricultural output. Farmers in affected areas are prone to experience significant financial strain due to decreased productivity, while the accumulation of toxic substances in crops raises concerns about food safety and public health. The study underscores the need for sustainable waste management practices, stricter regulatory enforcement, and appropriate location to mitigate the negative effects of dump sites on agricultural lands. This research contributes valuable insights into the development of policies aimed at improving environmental sustainability and agricultural resilience in urbanizing regions like Ibadan, Oyo State, Nigeria.
Copyright (c) 2026 Oluwafemi Ogundahunsi https://creativecommons.org/licenses/by/4.0
Effect of Land Preparation Methods on Growth Performance and Yields of Rice: A Case Study of Kimira-Oluch Irrigation Scheme, Homa Bay County, Kenya
Rice (Oryza sativa L.) is a critical staple in Kenya, yet its domestic production falls short of demand, increasing dependence on imports. Productivity in smallholder irrigation schemes remains constrained by inconsistent agronomic practices, particularly land preparation, which strongly influences soil structure, nutrient dynamics, and crop establishment. This study assessed the impact of various land preparation methods on rice growth parameters and yield at the Kimira-Oluch Irrigation Scheme in Homa Bay County, Kenya. A randomised complete block design was used, with treatments comprising tractor tillage, oxen tillage, hand tillage, and no-till, each replicated three times. Growth parameters measured included plant height, tiller number, tiller density, and leaf area index (LAI). Additionally, soil bulk density and porosity were determined. Grain yield was recorded at maturity and analysed using ANOVA and Tukey’s HSD tests at a 5% significance level. Results revealed significant differences among treatments. Tractor tillage consistently recorded the highest plant height, LAI, and yield, while oxen and human tillage produced moderate values, and no-till plots performed the poorest. Soil analysis showed lower bulk density and higher porosity under tractor tillage, conditions favourable for root development and nutrient uptake. Positive correlations were observed between growth parameters and yield, underscoring their predictive value in rice productivity. These findings highlight the importance of appropriate land preparation in optimising rice production in smallholder irrigation schemes.
Copyright (c) 2026 Lavenda Achieng, Japheth Onyando, John Langat https://creativecommons.org/licenses/by/4.0
Effects of Temperature and Solid-Liquid Ratio on the Extraction of Total Phenolic Content of Hibiscus Sabdariffa Leaves
Hibiscus sabdariffa leaves (HSL) can be used as tea leaves because of its bioactive compounds. This study demonstrates the effects of extraction temperature and solid liquid extraction ratio on the total phenolic content (TPC) of HSL. The HSL was harvested, washed dried with vacuum dryer at 40 °C and ground. The resultant powder was characterized in terms of tapped and bulk density, Carr’s index and Hausner ratio to ascertain its flow characteristics prior to the extraction using distilled water as the extraction medium at 70, 80and 90 °C and at the solid-liquid ratio of 1:9 and 3:7. The bulk and tapped density of 212m were 20.29 ± 0.1753 g/ml and 25.58 ± 0.2700 g/ml respectively .The carr index and Hausner ratio were 20.67 ± 1.154 and 1.26 ± 0.0185 respectively. Maximum extraction TPC was observed at 90 °C and at the solid-liquid ratio of 1:9 while the least TPC was observed at 70° C at 3:7 solid-liquid ratio.
Copyright (c) 2026 M. G Akpan, A. F Alonge, I. T Jerome https://creativecommons.org/licenses/by/4.0
Fish Freshness Sensing Using Changes in Eye Fluid Fluorescent Compounds of Tilapia (Oreochromis nilotica)
Ensuring the freshness of fish is crucial for determining its quality, influencing its appearance, and attracting consumers. Identifying spoiled fish in the early stages of spoilage is challenging for many consumers, necessitating the development of effective fish freshness evaluation methods. This study proposes the development of a fish freshness evaluation sensor applicable to farmers, wholesalers, and retailers in the tilapia fish value chain. The research focuses on determining the rate of change of fluorescent compounds in fish eye fluid and establishing the relationship between these changes and fish storage. High-performance liquid chromatography (HPLC) is employed for the identification of retinol (vitamin A) and pyridoxine (vitamin B6) in the eye fluid at different storage stages. The study also uses an ultraviolet/visible light spectrophotometer to measure the emissions of fluorescent compounds during various storage periods. The acquired data is utilized to validate the sensor, which integrates a microprocessor, spectroscopy sensor, and power source. The performance evaluation aims to establish the sensor's effectiveness in detecting changes in fluorescent compounds across different stages of fish storage. The results show that the concentration of retinol increased gradually and then reduces while that of the pyridoxine reduces to zero hence providing a valuable insight into a tool that can be applied throughout the tilapia fish value chain. This innovation could greatly enhance quality control processes in the seafood industry. Unlike traditional sensory evaluations, the sensor-based method boasts notable benefits, including greater objectivity and the capability for real-time assessments.
Copyright (c) 2026 Grace Njuguna, Stephen N. Ondimu, Sylvia I. Murunga, Peter Oduor Odote https://creativecommons.org/licenses/by/4.0
The Economic and Social Implications of Post-Harvest Losses of Some Selected Crops in Kano State, Nigeria
This study examines the economic and social implications of post-harvest losses of selected crops in Kano State, Nigeria. A region with vast agricultural potential where a significant portion of the population is engaged in farming. It focused on selected crops (some grains and vegetables) to investigate post-harvest losses among value chain actors. Covering 40 out of 44 Local Government Areas, the research utilized primary data collected through household surveys, structured questionnaires, and focus group discussions. A total of 1627 respondents participated in the study, representing various actors across different value chains of post-harvest loss. A combination of descriptive and inferential statistics were employed to analyze quantitative data using Statistical Package for Social Science (SPSS), while thematic analysis was used for qualitative data. The study examined socio-economic characteristics such as age, farming experience, household income, and post-harvest losses, providing valuable insights into the challenges farmers face and informing strategies to reduce losses and improve productivity. The survey revealed key demographic characteristics, including a significant gender disparity with females at 7.5% and males at 92.5%. The respondents had a reasonably skilled labor force, with 38.48% having secondary education and 27.72% having tertiary education. The majority (89.06%) were married, and farmers constituted the largest income group at 35.22%, highlighting agriculture's significance in the local economy. The results show that post-harvest losses significantly reduce farmers' income and exacerbate poverty in rural communities. The study highlights the need for effective post-harvest management strategies to enhance food security and improve farmers' welfare. The findings suggest that investing in post-harvest infrastructure, training farmers on best practices, and promoting agricultural innovation can help mitigate post-harvest losses and improve the livelihoods of farmers in Kano State.
Copyright (c) 2026 Taofiq Olanrewaju https://creativecommons.org/licenses/by/4.0
ENGINEERING ACCESSIBILITY IN NAIROBI CITY BY ROAD TRANSPORT INFRASTRUCTURE IN THE FACE OF CLIMATE CHANGE DILEMMA
Globally, climate change continues to present a monumental dilemma in all sectors of the economy. In the urban road transport system, it has become a norm that short distances between places end up consuming longer hours of travel by motorists on rainy days. This prolongation of travel time is occasioned by flooding risks. This makes places inaccessible. Accordingly, this study aimed at improving the accessibility of Nairobi city neighborhoods during wet weather. This informs the reason for use of the term, “engineering accessibility” which simply means to reduce travel time during wet weather between destinations. The study leverages the theory of infrastructure resilience in an attempt to extract developmental data in terms of mapping in the GIS Software environment, the incremental strides in road network lengths and tracing the incremental building footprints over the time scales covering years; 2000,2010,2020 and 2024.Secondly, rainfall data was sourced from KMD open source database that assisted in the development of flood map profile over the same time scale in HEC-RAS software. In the year 2000, built up area covered,50km squared, and the road network totaled 9630km.The worst flood depth recorded around Ojijo road in the period was 0.63m.In 2024,built up area was 83km2,road length was 14,720 and the flood depth at the same location was 1.83.This was the worst as exhibited in figure 3.In conclusion, the study has highlighted the need to mainstream resilience in storm water drainage system by deploying a continuous action plans.
Copyright (c) 2025 Eng. Dr. Elisha Akech https://creativecommons.org/licenses/by/4.0
EMPLOYING BINARY LOGISTIC REGRESSION ANALYSIS TO MODEL THE EFFECT OF DIFFERENT TREATMENTS ON QUALITY OF FRENCH BEANS (PHASEOLUS VULGARIS) PRODUCE
French beans (Phaseolus vulgaris L.) is a significant agricultural product in developing countries, contributing to economic development, employment, and exports. Despite extensive research on French bean farming in Kenya, limited attention has been given to factors influencing produce quality. This study employed a binary logistic regression model to evaluate the effect of slope, soil deposition, and different mulching materials: Farmers’ Practice (no mulch), polymer mulch, tea leaves mulch, and grass mulch on French bean quality in Ol’ Lessos Ward, Nandi Hills Sub-County, Kenya. Quality was defined as the absence of disease incidence. Field experiments measured slope percentage, soil deposition (g), yield (kg/plant), and disease incidence across treatments. Results revealed that slope alone had no significant effect on quality, but mulching significantly reduced soil deposition, increased yield, and lowered disease incidence compared to Farmers’ Practice. Polymer mulch recorded the highest yields and lowest soil deposits, while tea leaves and grass mulches also improved performance. Logistic regression analysis yielded a Cox and Snell’s R2 was 0.14 and Nagelkerke’s R2was 0.63 and the Nagelkerke R² which adjusts Cox and Snell’s value to a scale ranging from 0 to 1 was 0.628, suggested that the model had a strong explanatory power and a good overall fit. The findings underscore the critical role of mulching materials in enhancing French bean quality, independent of slope effects. Adoption of mulching, particularly polymer mulch, is recommended for sustainable production and improved marketability.
Copyright (c) 2025 C. Chepwogen, S.A. Mulindi, C.K. Kiptum https://creativecommons.org/licenses/by/4.0
SENSOR BASED CHARACTERIZATION OF SOIL PROPERTIES FOR SUNDARBAN
Sensor-based characterization of soil properties is inevitable due to the tedious, expensive, and time-consuming nature of traditional laboratory-based soil testing. This study focused on characterizing the soil properties of Indian Sundarban at depths of 0cm–20cm, 20cm–50cm, and 50cm–100cm using a PXRF, a Nix Pro color sensor, and a USB soil microscope. The soil samples belonged to mudflats in the intertidal zone and abandoned shrimp ponds. The soil samples were analyzed via Wet Digestion and Dry combustion for organic carbon (OC), total carbon (TC), and bulk density (BD). The average OC, TC, and BD at 0cm–20cm were 7.69 t/ha, 8.74 t/ha, and 1150 kg/m3, respectively. At 20cm–50cm, it was 11.73 t/ha, 13.08 t/ha, and 1239 kg/m3, respectively; 17.733 t/ha, 20.083 t/ha, and 1196 kg/m3, respectively, at 50cm–100cm. Modeling of OC, TC, and BD via multiple linear regressions was validated using R2 and RMSE. PXRF produced satisfactory results, with BD (R2 = 0.928; 0.9431; 0.998), SOC (R2 = 0.9785; 0.9297; 0.9726), and TC (R2 = 0.9938; 0.9619; 0.987). The Nix Pro color sensor with RGB, CIEL*A*b, and CMYK color spaces BD (R2 = 0.3769; 0.4786; 0.3894), SOC (R2 = 0.649; 0.3029; 0.4314), and TC (R2 = 0.4932; 0.2603; 0.5518). USB microscope with RGB color space underperformed, while similar performance sequence was observed using RMSE. Also, soil data was spatially analyzed to assess variability across three depths.
Copyright (c) 2025 S. Chakraborty, E.W. Mutayi https://creativecommons.org/licenses/by/4.0
EFFECT OF DEFICIT IRRIGATION ON THE GROWTH PARAMETERS, YIELD AND WATER USE EFFICIENCY OF COMMON BEANS (PHASEOLUS VULGARIS L) UNDER FOLIAR SELENIUM APPLICATION
Water scarcity remains a major constraint to sustainable crop production, particularly in arid and semi-arid regions. This study investigated the effects of foliar selenium (Se) application as water stress management strategy on common bean (Phaseolus vulgaris L.). It assessed growth and water productivity under Deficit Irrigation (DI). A greenhouse experiment was conducted at the Tatton Agricultural Park at Egerton University for one season using a randomized complete block design with three replicates. The experiment consisted of three irrigation regimes;100%, 70%, and 50% of crop evapotranspiration (ETc) and four selenium concentrations (0, 0.5, 1.0, and 1.5 mg/L). The results revealed that full irrigation 100% ETc and moderate water deficit at 70% ETc, combined with foliar application of 1.5 mg/L Se, significantly (p < 0.05) improved growth and yield parameters. Further, water productivity was highest under the 70% ETc and 1.5 mg/L by Se treatment, suggesting enhanced physiological efficiency and drought resilience. Selenium application mitigated the adverse effects of water stress by supporting plant metabolism, antioxidative defense, and stomatal regulation. Furthermore, the highest total pod yield (13177.8Kg/Ha) was obtained at 100% ETc combined with 1.5mg/L of foliar selenium, but statistically on pair with 70% ETc and 1.5mg/L of selenium concentration compared to the control treatment 100% ETc and no foliar selenium application (8785.2Kg/Ha), while the lowest pod yield (2288.9Kg/Ha) was attained at 50% ETc combined with no foliar selenium application. These findings demonstrate that supplying 70% ETc with 1.5 mg/L of selenium concentration instead of full water requirement can be a good strategic approach to improving water use efficiency and sustaining common bean production under limited water availability. The study provides valuable insight for developing climate-smart irrigation practices thus contributing to sustainable water management.
Copyright (c) 2025 V.L. Gamba, R.O. Okwany, S. Nyakach, P.B. Sesani https://creativecommons.org/licenses/by/4.0
PERFORMANCE EVALUATION OF A SINGLE STAGE FIXED DOME BIOGAS REACTOR ADAPTED FOR HUMAN WASTE TREATMENT AND BIORESOURCE RECOVERY
A performance evaluation of three first generation fixed dome anaerobic reactors installed in Kenya was undertaken to understand emerging design and operational deficiencies and inform design and scheme management improvements. These reactors were designed for decentralized human waste treatment and bio-resources recovery. Scheme management and reactor design configuration were explored while sixteen operating and performance parameters were monitored over 42 weeks using standard wastewater measurement techniques. The study results showed treatment efficiencies ranging from 26% to 51% for physicochemical parameters and 44% to 80% for microbiological indicators. However, effluent quality consistently failed to meet than World Health Organization and Food and Agriculture Organization (WHO/FAO) standards. Notably, Total Suspended Solids (TSS) in the effluent ranged from 1,843 to 2,299 mg/L—substantially higher than typical raw wastewater levels of 155 to 330 mg/L (median ~250 mg/L)—indicating poor solids removal. Chemical Oxygen Demand (COD) levels were between 735 and 2,522 mg/L (higher than WHO limit: ≤250 mg/L), Electrical Conductivity (EC) reached 5,140 µS/cm (WHO/FAO limit: ≤700 µS/cm for unrestricted irrigation), while microbial contaminants E. coli (2,254–2,370 MPN/100 mL) and helminths (31–52 eggs/100 mL) far exceeded limits for restricted irrigation (<1,000 MPN/100 mL and ≤1 egg/L, respectively). Additionally, the microbial log reduction value (LRV) was only 0.3, well below the WHO recommended LRV > 2 for secondary treatment. These findings confirm the reactors’ inadequate pathogen attenuation and pollutant removal, limiting safe effluent reuse. Design flaws that include straight-line inlet-outlet pipe configuration, low hydraulic retention times (2–5 days), and operation under psychrophilic temperatures (27–28 °C resulted in dead zones and poor flow dynamics. Systems that received more diluted influent (e.g., Gachoire) performed slightly better than those handling concentrated waste (e.g., Kibera). Still, none achieved adequate treatment. The computed Treatment Index (TI) values—0.58 (Gachoire), 0.52 (Naivasha), and 0.46 (Kibera)—confirmed the reactors’ inadequacy in reducing both microbial and chemical pollutants. Bioresource recovery potential was however demonstrated, with daily nitrogen recovery of 496.2 kg and biogas production of 60 m³. The findings underscore that single-stage fixed dome systems adapted from livestock applications are inadequately suited for human waste treatment. Advanced modelling, adoption of baffled or hybrid designs and integration of dual-metric performance evaluation (percentage removal and absolute concentrations) are recommended to improve treatment efficiency, ensure safe reuse, and achieve environmental compliance in future deployments.
Copyright (c) 2025 J.O Odhiambo, J.O Onyando, B.M Mutua https://creativecommons.org/licenses/by/4.0
The Changes in Rainfall and Temperature Under Representative Concentration Pathways Climate Scenarios in Kibwezi Watershed
Kibwezi watershed is highly susceptible to climate variability due to a mix of natural and anthropogenic stressors. This study assessed projected changes in rainfall and temperature using Regional Climate Models (RCMs) under RCP 4.5 and RCP 8.5 scenarios. RCM datasets were bias-corrected using the CMhyd tool, with CHIRPS and ERA5 serving as observational references. Seasonal and annual projections were analyzed for the short-term (2010–2039), mid-term (2040–2069), and long-term (2070–2100) 21st century relative to a historical baseline (1971–2005). Model evaluation indicated strong performance, with rainfall metrics of R² = 0.92, NSE = 0.64, PBIAS = -21.0%, and RMSE = 42.6 mm; and temperature metrics of R² = 0.92, NSE = 0.82, PBIAS = 0.90%, and RMSE = 0.56 °C. Rainfall is projected to increase by 24.5%-28.4% under RCP 4.5 and 21.5%-75.0% under RCP 8.5sceanrio across the three future periods. Seasonal shifts include increased rainfall during January-February and October-December, and decreases during March-May and June-August. Maximum temperatures are expected to rise by 0.6-1.5 °C (RCP 4.5) and 1.2-4.2 °C (RCP 8.5), while minimum temperatures will increase by 0.6-1.28 °C (RCP 4.5) and 0.68-2.40 °C (RCP 8.5). Spatially, the entire watershed is projected to experience warming and wetter conditions, with the eastern, central, and northern regions seeing the greatest rainfall increases and northern areas showing the highest temperature rise. These trends underscore the urgent need for climate-resilient watershed management strategies in the face of escalating climate risks.
Copyright (c) 2026 Reuben Cheruiyot Ruttoh, Dr., Dr., Mr. https://creativecommons.org/licenses/by/4.0
ANALYSIS OF ENGINEERING SOLUTIONS IN GRAIN STORAGE
Poor storage systems lead to losses of up to 50% of stored grain. Grains are stored by various systems in the value chain, which include piles on the ground, bag storage in ware houses, on the cob storage in cribs and bulk storage in silos and bankers. The cost of storage depends on the duration and quantity of storage. This also dictates if construction or renting the same as viable. The BCR (Benefit Cost Ratio) between construction and renting in a large scale is 0.7261. Renting is cheaper in large scale. Cost of storing in bulk storage in a silo is $ 2.95 per tonne in a year and $0.497 per kg per annum in a bag storage. This paper discusses the technical and economic merits of the various grain storage systems and provided proposals for development of storage systems which will enhance food security in developing counties.
Copyright (c) 2025 https://creativecommons.org/licenses/by/4.0
EVALUATING WASTE MANAGEMENT PRACTICES IN THE CONTEXT OF CLIMATE CHANGE ADAPTION AND MITIGATION IN AFRICA
Africa faces increasing challenges in waste management, exacerbated by rapid urbanization and climate change. This study evaluates waste management practices in Africa, highlighting factors, barriers, and enablers within the context of climate change adaptation and mitigation. Africa’s population is projected to reach 1.5 billion in 2024, intensifying pressure on its unevenly distributed natural resources. The continent faces interconnected issues, including biodiversity loss, water scarcity, energy shortages, and inadequate waste management. While 70-80% of Africa’s waste is recyclable, only 4% is recovered, highlighting inefficiencies in resource recovery and recycling efforts. Waste management in Africa suffers from weak policies, inadequate infrastructure, limited stakeholder engagement, and underfunding. Linear waste management systems dominate, failing to embrace circular economy principles. Poorly managed landfills contribute to methane emissions, impacting climate change, while plastic pollution threatens Africa’s aquatic ecosystems and biodiversity. Emerging waste streams, such as electronic and medical waste, further complicate efforts. This study aims to evaluate waste management practices in Africa, focusing on barriers, enablers, and opportunities for integrating climate change adaptation and mitigation strategies. Data was collected through journal article reviews, document analysis, and online resources. Key insights were synthesized to identify trends and challenges in waste management practices. Africa’s rapid urbanization and dynamic consumption patterns strain waste management systems. Weak policy frameworks, financial constraints, and inadequate investments hinder effective waste management. Climate change-induced extreme weather events complicate waste storage, collection, and treatment. Public awareness and community engagement remain insufficient, further undermining sustainable practices. To mitigate climate change impacts and enhance sustainable waste management in Africa, it is imperative to strengthen policy frameworks and enforcement mechanisms, invest in modern infrastructure and technologies, and promote circular economy principles to boost recycling and resource recovery. Additionally, fostering public awareness and stakeholder engagement is critical, alongside developing tailored strategies to address emerging waste streams such as electronic and medical waste. These integrated actions are essential for building resilient waste management systems that align with climate change adaptation and mitigation goals.
OPTIMIZING USE OF HYDROGEN PEROXIDE AND ULTRAVIOLET IRRADIATION TO IMPROVE WASTEWATER QUALITY FROM WET COFFEE PROCESSING
Wet coffee processing utilize large volumes of water in their processing operations. Wastewater from wet coffee processing contains high organic load, color and pH which results to pollution of the water ways when not properly treated. This study was aimed at evaluating the effectiveness of use of oxidizing agents and UV irradiation to improve the wastewater quality from Kabete coffee factory wet coffee processing. Wastewater quality aspects that were assessed include pH, turbidity biological oxygen demand (BOD) and chemical oxygen demand (COD). The quality of dam water used for the coffee processing was significantly low and within the range water quality standard for disposal established by NEMA. The analysis of the wastewater quality established that pH, BOD, COD and turbidity were higher in the coffee processing wastewater and pond treated water. The use of hydrogen peroxide (H2O2) independently resulted in significant improvement of wastewater quality. The treatment of the wastewater with H2O2 reduced BOD and the COD and 81% and 73% respectively. The H2O2 reaction time of 120 min showed the highest on the BOD and COD improvement up to 127 mg/l and 1048 mg/l respectively. UV irradiation alone recorded a reduced effect on the waste water quality, the BOD and the COD were improved by 26% and 35% respectively. The combination of UV irradiation and H2O2 (AOP) significantly enhanced the BOD, COD and turbidity of the wastewater. The combination of ≥ 0.4% H2O2 and 120 min of UV irradiation significantly enhanced the BOD, COD and turbidity of the effluent. Therefore, advanced oxidation process can provide an effective and efficient coffee processing water waste treatment.
A REVIEW OF SOLAR-POWERED IRRIGATION SYSTEMS (SPIS)
Solar-Powered Irrigation Systems (SPIS) have emerged as a sustainable solution to enhance agricultural productivity, particularly in regions facing unreliable or limited access to energy sources. By integrating photovoltaic (PV) technology with irrigation methods, SPIS provide an environmentally friendly and cost-effective alternative to conventional irrigation systems. This review synthesizes the design principles, components, operational challenges, advantages, and future developments of SPIS. This review paper was conducted using a systematic literature review approach. It evaluates case studies to assess their effectiveness in real-world applications and offers insights into overcoming the challenges associated with their deployment.
Copyright (c) 2025 Samuel Nyaanga, Duke Oeba, Jane Nyaanga https://creativecommons.org/licenses/by/4.0
INVESTIGATION OF PERFORMANCE OF BIOETHANOL COOKING FUEL AT DIFFERENT ETHANOL CONCENTRATION LEVELS
Most developing countries have much of their population cooking using unclean fuels. The use of dirty fuels in households results to Indoor Air Pollution (IAP) with negative impacts on human health. Increased use of firewood and charcoal results to degraded forest cover. However, most Countries have committed to promote clean cooking in line with the requirement of SDG7 and the Paris agreement of COP21. Ethanol has been identified and promoted as one of the cleanest fuels for cooking either as a gel or liquid of varying ethanol concentration. When processed from biomass, ethanol then referred to as bioethanol is seen to offer an affordable clean option for transitioning households to clean cooking. This study was to determine the optimal ethanol concentration in ethanol cooking fuel. Fuel samples of different ethanol concentration ranging from 50% to 95% at intervals of 5% were prepared from a 95% (190proof) ethanol fuel by mixing with distilled water and tested for fuel properties by conducting the Water Boiling Test. From experiments done, the lowest concentration that achieved boiling was 75%. The Fuel consumed, Specific Fuel Consumption, Time to Boil, Fire Power and Burning rate were found to be dependent on ethanol concentration and there was significant variation across the various concentrations. Thermal efficiency was not dependent on ethanol concentration and there was no trend observed across the various concentrations. Post Hoc comparison within groups indicated no significant difference in performance of the 90% and 95% ethanol concentration fuel samples. Given the corresponding energy demand and related cost of refining ethanol from 90% to 95% concentration, it was concluded that 90% ethanol concentration is the optimal concentration for ethanol cooking fuel while using a liquid ethanol stove with a fiber filled canister.
Copyright (c) 2025 Lucy Wangai, Joseph Muguthu, Eliud Njagi, George Momanyi https://creativecommons.org/licenses/by/4.0
AGRICULTURAL MACHINERY OPERATION TRAINING IN KENYA
Farm mechanization in Kenya is influenced by increasing population pressure, evolving farm structures, labor availability, and the costs and suitability of technology. Despite investing in expensive tractors, many farmers lack the knowledge to properly operate and maintain them, often leading to inefficiencies and soil degradation. In response, Egerton University, in partnership with Hello Tractor Ltd., the Micro-Enterprise Support Programme, and local tractor dealers, developed an agricultural machinery training program. This program is designed to equip farmers and tractor operators with the skills necessary to maximize machinery efficiency for improved yields while ensuring long-term farm profitability and sustainability. It features eight comprehensive modules that transform tractor drivers into certified agricultural machinery operators. Graduates earn a certificate of competency and a G12 endorsement on their driving licenses. The program’s assessment is divided into 30% theoretical learning and 70% practical fieldwork with agricultural machinery. With a target of training 10,000 operators, the program also aims to unlock financing opportunities for youth and women in agriculture. To date, approximately 280 participants have completed the training, with 85% achieving certification. The gender breakdown includes 86 women (31%) and 194 men (69%). Trainees highly rated the practical skills they acquired, such as ploughing, harrowing, tractor driving, operating planters and boom sprayers, and performing maintenance tasks. These hands-on experiences provide a deeper, more personal understanding of key agricultural concepts.
DEVELOPMENT OF AN IMPROVED LOW-COST SOLAR STILL FOR THE PRODUCTION OF POTABLE WATER FOR REGIONS WITH LOW SOLAR IRRADIANCE
Many developing countries are faced with inadequate access to potable water, especially in rural and peri-urban areas, where available freshwater is unsuitable for domestic use. Desalination is a potential solution for purifying polluted or saline water, but common methods are energy-intensive, driving interest in more economical options like solar distillation. Solar distillation, which uses a solar still for water purification, is a promising method but is often limited by low productivity. Single-basin solar stills typically achieve less than 5 litres of freshwater per square meter per day, necessitating further research to enhance output. The primary objective of this study was to develop a cost-effective solar still by incorporating paraffin wax as a phase change material coupled with a heating element (soleplate of a solar pressing iron) to boost productivity. Findings showed that productivity increased with the mass of paraffin wax, reaching a maximum value of 8.6 liters per square meter. Productivities were recorded as 0.75 litres per square meter for the passive solar still, 4.2 litres per square meter for the active solar still, and a peak of 8.6 litres per square meter for the enhanced solar still, reflecting a 104.8% increase in productivity. With a basin water volume of 3 litres, the conventional solar still reached a maximum temperature of 41.2°C, while the enhanced solar still achieved 89.6°C. The cost of water production from the solar still was estimated at $0.01 per litre.
Poultry farming in Kenya plays a major role in complementing rural and peri-urban households’ food security and income. Farmers have turned to rearing of improved indigenous chicken (IC) due to the fast growth and high production of eggs; one of the strategies used to enhance development of IC is to supply day old chicks to producers. However, the demand for day old chicks outstrips supply because of low hatchability experienced in small holder hatcheries. This study characterized the hatching systems in Siaya County. A survey was conducted on small holder farms and hatcheries to establish characteristics of hatching systems in Siaya County. The study showed that the breeding stock were reared in enclosed and free-range systems with a dominant species of Sasso kuroiler, kenbro and KALRO improved chicken, 55% of the farms attained the standard cock to hen ratio of 1:7 and eggs were stored using both conventional and non-conventional methods. The management practices of the hatchery systems fell outside the standard practices and this contributed immensely for poor performance of farming enterprises. Adoption and implementation of standard practices in hatching systems will contribute to higher performance.
ANALYSIS OF SPATIOTEMPORAL VARIATION OF RIVER SOSIANI WATER QUALITY IN WESTERN KENYA
This study evaluates spatiotemporal variation in physiochemical properties of River Sosiani water in Eldoret, Kenya. River Sosiani is an essential supply of water for the residents and industrial activities in Eldoret town. Water Samples were collected in six sampling point along River Sosiani for a period of six months in dry and rainy season and analyzed in accordance with APHA water sampling and processing procedure. Data was managed and analyzed using Excel data analysis function. One way ANOVA and paired t-test analysis were used to determine statistically significant variation in physiochemical parameters along River Sosiani. River Sosiani exhibited spatial variation of all water quality parameters between the means for DO (P=1.20E-19), BOD (P=8.32E-83), Temperature (P=6.00E-13), EC (P=5.32E-14), TDS (P=3.18E-13), pH (P=1.15E-28), Nitrate-N (P=1.49E-33) and TP (P=1.06E-30). Seasonally, all parameters indicated significant temporal variation between the means for DO (P=5.66E-18), BOD (P=2.38E-03), Temperature (P=3.92E-11), EC (P=3.81E-10), TDS (P=1.31E-09), pH (P=1.35E-02), Nitrate-N (P=1.38E-13) and TP (P=6.72E-08). Some of the physiochemical parameters tested were within the recommended WASREB, NEMA and WHO permissible limits for drinking water. However, the study conclusively showed that the water quality of River Sosiani is deteriorated and hence unsuitable for human use. The study recommends urgent measures to conserve the catchment be undertaken and restoration of degraded river section to ensure sustained future provision of ecological services to riparian communities and enhance river’s biological integrity.
PERFORMANCE OF A LOCALLY FABRICATED ONE-ROW POTATO HARVESTER FOR WALK-TRACTOR
This study evaluates the performance of a locally fabricated one-row mechanized potato harvester designed for small and medium-scale farms in Kenya, focusing on its efficiency across different soil conditions. Mechanized harvesting addresses inefficiencies and post-harvest losses in potato farming, particularly in Kenya's diverse agricultural environments. The harvester was tested under dry soil (moisture content below 15%) and moderately wet soil (moisture content between 20% and 25%) conditions. Key performance metrics assessed included harvesting efficiency, tuber damage rate, fuel consumption, and field capacity. The harvester achieved an average efficiency of 93.4%, with higher performance observed in moderately wet soil (94.7%) compared to dry soil (92.1%). The average tuber damage rate was 4.2%, with more significant damage occurring in dry soil (4.8%) than in wet soil (3.6%). Fuel consumption remained consistent at 2.5 liters/hectare, and field capacity was measured at 0.4 hectares/hour. These results demonstrate the harvester's reliability and adaptability to local farming conditions, providing a mechanical potato harvesting solution for small-scale farmers in Kenya.
EVALUATION OF MAINTENANCE EFFECTIVENESS AND HUMAN FACTORS: CASE STUDY OF A RESEARCH INSTITUTE
Maintenance management is an integral part of any organization’s overall commercial process that develops administrative operational value. Thus, the maintenance function is of immense importance to ensure the safety and effective operation of a facility and equipment in compliance with a statutory obligation, to maximize equipment life, and to reduce the risk of failure. However, for maintenance success work planning, the perception of human factors, and the interrelation of workers and groups in any organisation must be understood. This in turn would determine the allocation of maintenance tasks to team members. This research focused on the evaluation of key performance indicators in relation to the maintenance effectiveness of selected equipment, in a research institution. The impact of human factors on the maintenance was also investigated. Key performance indicators such as Mean Time to Repair (MTTR), Mean Time Between Failure (MTBF), downtime, repair time, and availability were used to quantitatively evaluate the maintenance effectiveness of the equipment, while the systematic approach to empirical research was used to analyse the effect of human factors on maintenance practices. This study was carried out over a period of 6 months on a 4-tonne hydraulic lift, hydraulic hoist jack lift, tire changing machine, fault diagnostic machine, and computerized alignment gauge. Data collected from the maintenance unit was analysed. A total of 11.92 hours was recorded as the MTTR of the five machines. The machines had a high level of availability and a total downtime of 12.01 hours out of operational time of 2369.8 hours over a period of 6 months. The level of motivation and competence among maintenance personnel was assessed to be very good. This is expected to have contributed largely to the effective maintenance practices of workers in the unit. From this study, it can be deduced that the level of motivation and competence is high among maintenance personnel. In terms of productivity, effectiveness, teamwork, decision-making, execution, safety, and responsiveness, the human factor has been shown to have thrived well. This in turn, stimulated the corresponding increase in the availability of machines over the 6 months- of study.
Copyright (c) 2024 https://creativecommons.org/licenses/by/4.0
SIMULATION OF SPATIO-TEMPORAL DYNAMICS OF STREAM FLOW TO CLIMATE VARIABILITY IN NJORO RIVER CATCHMENT, KENYA
Climate variability continues to alter hydrological regimes and the response of many catchments globally thus threatening water security. Njoro River Catchment has not been an exception. There is a steady recognition of climate variability and adverse influences like deterioration of ecosystems, surface, and groundwater sources. Therefore, the study focused on modelling the impact of climate variability on the spatial and temporal distribution of stream flow in the Njoro River Catchment, Kenya. Modelling of stream flow response to climate variability using SWAT was carried out based on USGS/NASA downloaded Digital Elevation Model, FAO soil data, Landsat (MSS 1-5) LULC of 1978, and meteorological data for the period (1978 - 2017). Simulation of spatial and temporal impacts of climate variability was then carried out. Based on the analysis, SUFI-2 algorithm results revealed that the most sensitive parameter in Njoro River Catchment is SCS curve number for antecedent moisture condition (II) (CN2), ranked according to the highest sensitivity tested at p < 0.05. The least sensitive parameter is maximum canopy storage (CANMX). Overall uncertainty analysis results showed a good performance value of P-factor (0.72) and R-factor (0.38), which indicated that SWAT reproduced the dynamics of the catchment hydrologic response relatively well. The values of R2, NSE, and PBIAS for calibration and validation of monthly stream flow were 0.88 and 0.77, 0.86 and 0.74, and 5.51 % and -15.42 % respectively. From the spatio-temporal impacts of climate variability on hydrologic variables, actual evapotranspiration increased by about 5.6 %, 3 %, and 6.62 % in the 2nd, 3rd, and 4th decades. Surface runoff decreased in the 2nd decade by 34.56 % and increased by 4.55 % and 34.02 % in the 3rd and 4th decades. Annual water yield decreased in the 2nd decade by 29.69 % and increased by 4.25 % and 60.18 % in the 3rd and 4th decades respectively. On average, stream flow reduced by 30.91 % in the 2nd decade and increased by 5.47 % and 63.63 % in the 3rd and 4th decades respectively. These findings provide pertinent insights, which may perhaps enlighten decision-making in designing adaptable mitigation measures, catchment rehabilitation, and strategic initiatives for the integrated management of water resources.
RICE PROCESSING TECHNIQUES AND EFFICIENCY DIFFERENTIALS IN NIGERIA
The techniques of rice processing determine output optimization and level of efficiency of processors. This study was carried out to augment the dearth of knowledge of efficiency differentials of rice processing techniques in Nigeria. Analytical approaches include descriptive statistics and Data Envelopment Analysis-(DEA) which were used in analysing information from 410 rice processors in Nigeria. Index of processing techniques was traditional-techniques-(trad=<0.2-0.39); traditional and modern-Techniques-(trad-modern=0.40-0.79) and Purely Modern-Techniques-(purely-modern=>0.79). The results showed overall, 20.4%, 65.7% and 13.9% used Trad, Trad-modern and Purely-modern techniques of processing, respectively. Technical Efficiency (TE) was 0.4±0.3, 0.5±0.6 and 0.8±0.9 for trad, trad-modern and purely-modern techniques, respectively. Allocative Efficiency (AE) was 0.4, 0.6 and 0.9; while Economic Efficiency (EE) was 0.8, 0.3, 0.2. The TE differentials for trad-techniques relative to purely-modern and trad-modern techniques were 0.45 and 0.11, respectively. The AE differentials for trad-techniques relative to purely-modern techniques and trad-modern techniques was 0.01, while EE differentials for trad-techniques relative to the other two techniques was 0.6. The study shows rice processing in Nigeria exhibits a range of outcomes based on techniques used. While traditional methods persist due to their low cost, larger processors are increasingly adopting trad-modern and purely-modern techniques to improve efficiency and product quality. Addressing the efficiency differentials in rice processing requires a comprehensive approach, including investments in technology, infrastructure, and skill development to foster food security in Nigeria. These findings therefore challenge the notion that traditional-modern and purely modern techniques are less technically efficient than traditional techniques in rice processing.
BIOPOTENTIAL PROPERTY OF MAGGOTS AS INOCULUM IN ANAEROBIC DIGESTION OF SUBSTRATES FOR BIOGAS PRODUCTION
A possible way of enhancing biogas yield from substrates is through the introduction of inoculum in a form of biomaterial with potential of increasing microbial population. Therefore, this research evaluated biopotential property of maggots as inoculum in anaerobic digestion of substrates for biogas production. The substrates used in the study are chicken droppings (CD) and swine dung (SD). The experiment was set up using biodigesters, water tanks with collectors. Cube-shaped plastic kegs of 25 L was adapted as biodigesters. The biodigesters were batch loaded and filled to 75% capacity, amounting to 18.5 L working volume with retention time of 5 weeks (35 days). During this retention time, the ambient and substrate temperatures were measured daily including the biogas yield while the pH was measured weekly. The result demonstrated that pH was within the range of 6.80-7.31, which is found to be within the standard of 6-8 pH level considered suitable for existence of anaerobic bacteria. Similarly, the mean temperature varied between 28.3-35.2ºC which is found to be within the range of 25-35 ºC reported to be suitable for the necessary anaerobic bacteria to survive. Furthermore, the total biogas yield for substrates treatment with maggots were higher compared with substrates treatment without maggots. This is an indication that the maggots have potential to enhance biogas yield when used as inoculum in production of biogas. Consequently, biogas production at higher yield can significantly reduce the overdependence on fossil fuels and other non-renewable forms of energy.
PERFORMANCE EVALUATION OF EXPERIMENTAL SOLAR EVAPORATIVE COOLING SYSTEMS
Evaporative cooling systems have many advantages over refrigeration systems, such as not necessarily requiring connection to the national grid, not using refrigerants that emit ozone-depleting substances into the environment, and can be constructed from locally available materials. However, little information on incorporating desiccant as an air preconditioning component to increase the performance of these coolers is available. In this regard, this study aimed to examine the efficacy of three cooling systems: an evaporative cooler with a silica gel desiccant component (desiccant cooler), an evaporative cooler without desiccant (desiccant-free cooler), and an evaporative charcoal cooler (charcoal cooler). Dry and wet bulb temperatures and relative humidity were recorded during the experiment and used to determine the cooling efficiencies of the systems; temperature drops; and humidity increases, which are used as performance indicators. Results demonstrate a significant (P<0.05) impact of the coolers on all analysed parameters. The desiccant cooler achieved the highest cooling efficiency at 87.2%, followed by the charcoal cooler at 79.3%, and the desiccant-free cooler at 67.2%. Temperature reduction was most pronounced in the desiccant cooler (3.7°C), followed by the charcoal cooler (3.2°C) and the desiccant-free cooler (2.8°C). Relative humidity levels increased by 30.7%, 23%, and 26.1% in the desiccant, desiccant-free, and charcoal coolers, respectively. Importantly, the evaporative cooler with desiccant operated without ozone-depleting refrigerants and utilized solar energy, offering an environmentally friendly solution. Its capacity to provide appropriate storage conditions for a wide range of fruits and vegetables makes it particularly beneficial for farmers lacking access to adequate cooling storage facilities, enabling them to preserve their produce effectively.