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Levels of Polycyclic Aromatic Hydrocarbons (PAHs) in Healthcare Waste Incinerators’ Bottom Ash from Five County Hospitals in Kenya  [PDF]
Muriithi Jackson Githinji, Paul Mwangi Njogu, Zipporah Nganga, Mohamed Karama
Journal of Environmental Protection (JEP) , 2024, DOI: 10.4236/jep.2024.153018
Abstract: Health-care waste contains potentially harmful microorganisms and compounds which can infect and affect hospital patients, healthcare workers, the general public and environment. Therefore, management of health care waste requires safe handling, treatment and disposal procedures. While incineration reduces the volume and quantity of waste for final disposal, it leads to the production of fly and bottom ashes laden with toxic incomplete combustion products such as Polycyclic Aromatic Hydrocarbons (PAHs), dioxins, furans and heavy metals. This exposes workers who handle and dispose the bottom ashes, hospital patients, the general public and environment. The goal of this study was to determine the total and individual levels of 16 most prevalent and toxic PAHs. Bottom ash samples were collected from incinerators in five county hospitals in Kenya, namely; Moi-Voi, Narok, Kitale, Makindu and Isiolo. Bottom ash samples were collected over a period of six months from the five hospitals. The samples were then sieved, homogenised and stored at 4°C in amber coloured glass containers. The PAHs were extracted using 30 ml of a hexane-acetone solvent (1:1) mixture by ultrasonication at room temperature (23°C) for 45 minutes. The PAHs were then analyzed with a GC-MS spectrophotometer model (Shimadzu GCMS-QP2010 SE) connected to a computer work station was used for the PAHs analysis. The GC-MS was equipped with an SGE BPX5 GC capillary column (30 m × 0.25 mm × 0.25 μm) for the separation of compounds. Helium was used as the carrier gas at a flow rate of 15.5 ml/minute and 14.5 psi. 1 μl of the sample was injected at 280°C, split mode (10:1). The oven programming was set for a total runtime of 40 minutes, which included: 100°C (2-minute hold); 10°C /min rise to 200°C; 7°C /min rise to 249°C; 3°C /min rise to 300°C (2-minute hold). The interface temperature was set at 290°C. Analysis was done in Selected Ion Monitoring (SIM) mode and the peak areas of each of the PAHs were collected from the chromatograph and used for quantification of the 16 PAHs listed by the U.S. Environmental Protection Agency (EPA) which included, BaA (benz[a]anthracene: 4 rings), BaP (benzo[a]pyrene: 5 rings), BbF (benzo [b]fluoranthene: 5 rings), BkF (benzo[k]fluoranthene: 5 rings), Chr (chrysene: 4 rings), DbA (dibenz[a,h]anthracene: 5 rings), InP (indeno[1,2,3 - cd] pyrene: 6 rings) and Acp (acenaphthene: 3 rings), Acpy (acenaphthylene: 3 rings), Ant (anthracene: 3 rings), BghiP (benzo[g,h,i]perylene: 6 rings), Flu (fluorene: 3 rings), FluA (fluoranthene:
Development and Application of Integrated Indicators for Assessing Healthcare Waste Management Systems in Kenyan Hospitals  [PDF]
Muriithi Jackson Githinji, Paul Mwangi Njogu, Zipporah Nganga, Mohamed Karama
Open Journal of Applied Sciences (OJAppS) , 2024, DOI: 10.4236/ojapps.2024.144072
Abstract: Healthcare waste management (HCWM) is an important aspect of healthcare delivery globally because of its hazardous and infectious components that have potential for adverse health and environmental impacts. The paper introduces a set of indicators for assessing HCWM systems in hospitals. These indicators are: HCWM policies and standard operating procedures, management and oversight, logistics and budget support, training and occupational health and safety, and treatment, disposal and waste treatment equipment housing. By plotting a mark on a continuum which is defined as good and poor on the extremes and is connected with all other marks in a spoke arrangement, it’s possible to describe a baseline for HCWM in any specific hospital. This baseline can be used to improve awareness of the actors and policy-makers, compare the same hospital at a different point in time, to compare observations by different evaluators and to track improvements. Results suggest that in Kenya, the application of such indicators is useful for evaluating which priorities should be addressed to improve outcomes in HCWM systems. Systematic sampling technique was used to identify and collect data by use of observational checklist, interviews, visual verification and review of documents and a HCWM assessment tool. The objective is to suggest an integrated management tool as a method to identify prevailing problems with a HCWM system. The method can be replicated in other contexts worldwide, with a focus on the developing world. The integrated indicators focus on management of HCW and not its potential impact on human health and environment, an area recognized to be critical for future research.
Distribution and Concentrations of Heavy Metals in Tropospheric Suspended Particulate Matter (PM10) In Nairobi City, Kenya  [PDF]
Faith Ndunge Mutua, Paul Njogu, Christopher Kanali
Open Journal of Applied Sciences (OJAppS) , 2021, DOI: 10.4236/ojapps.2021.118066
Abstract: Air pollution present the greatest threat to human health and welfare in urban environments. Population growth, industrial activities, expanded transport system, vehicular traffic, poor road planning, poor land use and traffic congestion contribute to the problem. Particulate matter (PM2.5？and PM10) has become the principal pollutants due to increased material use, energy demand and use as a result of global economic growth. This study assessed the levels of PM10？in ambient air and heavy metal composition in Nairobi city. Sampling sites were classified into three categories namely; controlled areas, industrial and residential areas as proscribed in the EMCA Air Quality Regulations, 2014. Portable Mini-Vol ambient air samplers were used for fine particulate monitoring. The concentrations of manganese, lead, and cadmium was determined in PM10？samples from all sampling sites. The lead concentration mean was 0.07 ± 0.06 μg/m3, 0.34 ± 0.35 μg/m3？and 1.10 ± 0.59 μg/m3？for residential, controlled and industrial areas respectively. Generally, all afternoons had high particulate matter while the lowest concentration levels of PM10？were recorded at night.
Biogas Production Using Water Hyacinth (Eicchornia crassipes) for Electricity Generation in Kenya  [PDF]
Paul Njogu, Robert Kinyua, Purity Muthoni, Yusuyuki Nemoto
Energy and Power Engineering (EPE) , 2015, DOI: 10.4236/epe.2015.75021
Abstract: Water hyacinth, E. crassipes, an invasive water weed thrives in fresh water bodies causing serious environmental problems. In Kenya the weed has invaded Lake Victoria and poses great socioeconomic and environmental challenges. Currently the weed is harvested from the Lake and left in the open to rot and decay leading to loss of aesthetics, land and air pollution. There is therefore need for development of value addition and economic exploitation strategies. The aim of the study is to assess the potential for utilization of the weed as a renewable energy resource for biogas production. Samples were collected from Lake Victoria, pulped and blend with cow dung at a ratio of 3:1 as inoculum. The resultant mixture was mixed with water at a ratio of 1:1 and fed into a 6 m3 tubular digester. The digester was recharged with 20 kg after every three days. The temperature, pH variations, gas compositions, upgrading and gas yields were studied. The temperature ranged between 22.8°C - 36.6°C and pH 7.4 - 8.5. Biogas was found to contain 49% - 53% methane (CH4 ), 30% - 33% carbon dioxide (CO2 ), 5% - 6% nitrogen (N2 ) and traces of hydrogen sulphide (H2S). The biogas was upgraded using solid adsorbents and wet scrubbers increasing the methane content by up to 70% - 76%. The upgraded gas was used to power internal combustion engines coupled with an electricity generator and direct heat applications. The study concludes that E. crassipes is a potential feedstock for biogas production especially in areas where it is abundant.
Thermal Gasification of Rice Husks from Rice Growing Areas in Mwea, Embu County, Kenya  [PDF]
Paul Njogu, Robert Kinyua, Purity Muthoni, Yusuyuki Nemoto
Smart Grid and Renewable Energy (SGRE) , 2015, DOI: 10.4236/sgre.2015.65010
Abstract: Thermal gasification of biomass provides a potential renewable energy resource in rural areas in Kenya. Rice husks are a key byproduct of rice production that are not considered of economic value to millers. Rice husks obtained from Mwea, Embu County, Kenya were converted into syngas using a locally assembled modified updraft gasifier. The syngas production was produced at temperatures between 450°C and 750°C with injection of limited supply of air and purified using series of gas cleaning and cooling devices. Proximate analysis shows that rice husks have a mean content of 21.9% ± 0.3% ash, 9.5% ± 3.3% moisture, 78.8% ± 0.3% volatiles and 91.8% ± 1.3% total solids. Carbonized rice husks have mean contents of 37.8% ± 1.2% ash, 3.1% ± 0.4% moisture, 62.3% ± 1.2% volatiles and 96.5% ± 0.4% total solids. The study shows that feedstock is consumed at a rate of 25 - 32 Kg/Hr with gas generation rate of 7.76 - 7.78 m3/hr; this translates to a gas yield of 0.31 - 0.35 m3/Kg. Process water was re-circulated at a rate of 2.2 m3/hr within the plant. The total electricity consumption per hour was 1.1 - 1.3 kWh. Carbon monoxide (CO) and temperature were monitored in the working area to assess the safety of the workers and were found to be in the range of 35 - 50 ppm and 24°C - 29.5°C respectively. The two were found to be within safe limits; however, the CO concentrations increased when leakages occurred. Syngas was found to be composed of 16.5% - 17.55% CO, 14.5% - 16.1% CO2, 4.1% - 4.5% H2, 6.8% - 7.2% CH4 and 17.9% - 45.7% N2 among others. The gas was used for direct heating applications and to run modified petrol engines. Carbonized husks were used to make energy briquettes and partly applied to the rice growing pads to improve soil properties. The technology provides energy solutions and aids in the abatement of climate change mitigation and abatement since it provides a permanent carbon sink. The technology provides a value addition chain for rice growers.
Wet Coffee Processing Discharges Affecting Quality of River Water at Kayanza Ecological Zone, Burundi  [PDF]
Emile Bisekwa, Paul M. Njogu, Taye Kufa-Obso
Open Journal of Applied Sciences (OJAppS) , 2021, DOI: 10.4236/ojapps.2021.116052
Abstract: Wet coffee processing leads to the generation of large volumes of wastewater, whose discharge to the environment leads to pollution of freshwater bodies. Kayanza is a major coffee growing area in Burundi with more than 40 wet coffee processing factories (WCPF) that discharge effluents directly to receiving water bodies without treatment. This study was carried out to assess the effect of coffee wastewater on the physicochemical properties of receiving waterbodies in Kayanza coffee growing ecological zone. Currently, no study has been done to analyze the effluent from the WCPF and assess the level of pollution. This study will therefore provide valuable data on the water pollution from coffee processing plants. Ten (10) rivers in the Kayanza coffee growing zone were studied during the months of April and June, 2020. Water samples were collected upstream (U) and downstream (D) of the effluent discharge points in triplicate. Samples were analyzed for pH, Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD5), Temperature, Salinity, Electrical Conductivity (EC), Total Dissolved Solids (TDS), Dissolved Oxygen (DO), Total Suspended Solids (TSS), Nitrates, Nitrites, Lead (Pb), Copper (Cu), Chlorides and Ammonium ions using standard methods. Physical parameters were analyzed in situ whereas chemical parameters were analyzed in the laboratories in Burundi Institute of Agricultural Sciences (ISABU) and University of Burundi. Data were analyzed using R-studio-1.0.153, GenStat 64-bit Release 14.1 and SSPS. Results on the physicochemical parameters indicated that coffee factory effluent has a polluting potential during coffee processing peak. The concentrations of the physicochemical parameters were significantly (p < 0.05) higher downstream (D) compared to upstream (U) of the river water sampling points. All downstream sites had COD, BOD5, TSS and pH values above allowable limits set by WHO and Burundi. The polluting impact of public wet coffee processing factories was significantly higher than that of private and cooperatives owned factories (p < 0.05). Measures should be taken in order to protect water bodies.
Kinetics and Process Studies of the Potential for Transformation of Biogas to Biomethane and Liquefaction using Cryogenic Liquid for Domestic Applications  [PDF]
Benard Ogembo, Paul Njogu, Francis Ochieng
Energy and Power Engineering (EPE) , 2023, DOI: 10.4236/epe.2023.156011
Abstract: The present work dealt with the generation, purifying and liquefaction of biomethane to improve energy density using local materials for domestic applications. Cow dung was sourced at JKUAT dairy farm and experiments were conducted at JKUAT Bioenergy laboratory using biogas generated in laboratory scale 1 m3 bioreactors. Experiments were done in triplicates and repeated under different conditions to get the optimal conditions. The results showed that enhanced cow dung substrate displayed an improved fermentation process with increased biogas yields. Purified biogas optimized methane content from 56% ± 0.18% for raw biogas to 95% ± 0.98% for biomethane which was ideal for liquefaction.
Mixture Ratio Estimators Using Multi-Auxiliary Variables and Attributes for Two-Phase Sampling  [PDF]
Paul Mwangi Waweru, John Kung’u, James Kahiri
Open Journal of Statistics (OJS) , 2014, DOI: 10.4236/ojs.2014.49073
Abstract: In this paper, we have proposed three classes of mixture ratio estimators for estimating population mean by using information on auxiliary variables and attributes simultaneously in two-phase sampling under full, partial and no information cases and analyzed the properties of the estimators. A simulated study was carried out to compare the performance of the proposed estimators with the existing estimators of finite population mean. It has been found that the mixture ratio estimator in full information case using multiple auxiliary variables and attributes is more efficient than mean per unit, ratio estimator using one auxiliary variable and one attribute, ratio estimator using multiple auxiliary variable and multiple auxiliary attributes and mixture ratio estimators in both partial and no information case in two-phase sampling. A mixture ratio estimator in partial information case is more efficient than mixture ratio estimators in no information case.
Mesophilic Process and Kinetics Studies of Selected Biomolecules as Potential Enhancers of Biomethanization of Cow Dung in an Anaerobic Tubular Batch Reactor  [PDF]
Paul Njogu, Francis Xavier Ochieng, Benard Ogembo, Stephen Ondimu, Christopher Kanali, Erick Ronoh, Daniel Omondi, Hiram Ndiritu
Energy and Power Engineering (EPE) , 2022, DOI: 10.4236/epe.2022.143007
Abstract: Mesophilic biogas production and substrate decomposition is one of the significant limiting steps in biogas generation. The rate of generation and quality often affect the viability of biogas systems. This study assessed the potential for biogas process catalysis using powdered Sorghum bicolor L., Zea mays, and Pennisetum glaucum. The kinetics and biogas generation processes were studied. Experiments were conducted in 1 m3 tubular batch reactors, where batches were dosed with various organic biomolecules. Results show that the use of P. glaucum L. and S. bicolor L. reduced the biogas retention times significantly. Biogas generation commenced after the first day for digesters fed with S. bicolor L. and P. glaucum L. while one with Z. mays and control occurred on day two. The rate of biomethanation and methane content were enhanced. S. bicolor L. led to the highest methane content. Findings reveal that locally available organic biomolecules improved biogas quality and quantity.
Association between Respirable Dust Exposure and Respiratory Health Concerns among Workers in Apparel Processing Companies in Export Processing Zone (EPZ) in Machakos County, Kenya  [PDF]
Owino A. Otieno, Paul M. Njogu, Dennis Magu
Occupational Diseases and Environmental Medicine (ODEM) , 2022, DOI: 10.4236/odem.2022.104021
Abstract: Apparel processing is an essential industry in providing clothing needs for the population. The Export Processing Zone (EPZ) in Kenya employs many employees. Garment processing releases respirable dust particles, thus exposing workers to risks to the respiratory system. The study determined the respirable dust health concerns among workers in Apparel Processing Companies (APCs) in EPZ in Machakos County, Kenya. A cross-sectional descriptive design was employed where four companies were studied. Three hundred and sixty-seven participants were selected through systematic random sampling. Data was collected using questionnaires and Interview guides. The study established that workers were exposed to respirable dust PM2.5 ranging from 40.89 ± 24.0 μg·m−3 to 87.49 ± 45.2 μg·m−3 with a mean of 65.61 ± 31.5 μg·m−3. While PM2.5 ranged from 63.59 ± 21.2 μg·m−3 to 313.41 ± 468.0 μg·m−3. With a mean of 104.02 ± 26.0 μg·m−3. Workers complained of different respirable dust-related diseases. The most prevalent conditions were sneezing and coughing (86.4%), chest pains (41.1%), blocked chests (36.8%), and allergic reactions to dust (18.3%). The APC should develop an OSH management system that includes; a dust management policy, dust monitoring, Risk Assessments, Engineering controls installations, medical examination, Training on dust management, PPE provision, and use enforcement.
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