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 w...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: 4 rings), Nap (naphthalene: 2 rings), PhA (phenanthrene: 3 rings) and Pyr (pyrene: 4 rings). Ion source-interface temperature was set at 200°C - 250°C. Internal standards from Sigma Aldrich were used in the analysis and the acquired mass spectra data were then matched against the NIST 2014 library [1] [2]. The mean PAHs concentration in the bottom ashes of each hospital varied broadly from 0.001 mg/kg to 0.4845 mg/kg, and the mean total concentration levels of individual PAHs ranged from 0.0072 mg/kg to 1.171 mg/kg. Low molecular weight PAHs (Phenanthrene, Naphthalene and Fluorene) were predominant in all the hospital wastes whereas Kitale and Narok presented the lowest PAHs concentrations and the lowest number of individual PAHs. Moi/Voi recorded the highest total PAHs concentration at 1.3129 ± 0.0023 mg/kg from a total of 11 PAHs being detected from the bottom ash samples. Narok had only three PAHs being detected at very low concentrations of 0.0041 ± 0.00 mg/kg, 0.0076 ± 0.00 mg/kg and 0.012 ± 0.00 mg/kg for phenanthrene, anthracene and chrysene respectively. This study presents hospital incinerator bottom ash as containing detectable levels of both carcinogenic and non-carcinogenic PAHs. Continued unprotected exposure of hospital workers (waste handlers) to the bottom ash PAHs could be hazardous to their health because of their cumulative effect. Preventive measures e.g. the use of Personal protective equipment (PPE) should be prioritised to minimise direct contact with the bottom ash. The study recommends an upgrade on incinerator technology for efficient combustion processes thus for better pollution control.展开更多
Healthcare wastes contain potentially harmful microorganisms, inorganic and organic compounds that pose a risk to human health and the environment. Incineration is a common method employed in healthcare waste manageme...Healthcare wastes contain potentially harmful microorganisms, inorganic and organic compounds that pose a risk to human health and the environment. Incineration is a common method employed in healthcare waste management to reduce volume, quantity, toxicity as well as elimination of microorganisms. However, some of the substances remain unchanged during incineration and become part of bottom ash, such as heavy metals and persistent organic pollutants. Monitoring of pollution by heavy metals is important since their concentrations in the environment affect public health. The goal of this study was to determine the levels of Copper (Cu), Zinc (Zn) Lead (Pb), Cadmium (Cd) and Nickel (Ni) in the incinerator bottom ash in five selected County hospitals in Kenya. Bottom ash samples were collected over a period of six months. Sample preparation and treatment were done using standard methods. Analysis of the heavy metals were done using atomic absorption spectrophotometer, model AA-6200. One-Way Analysis of Variance (ANOVA) was performed to determine whether there were significant differences on the mean levels of Cu, Zn, Pd, Cd and Ni in incinerator bottom ash from the five sampling locations. A post-hoc Tukey’s Test (HSD) was used to determine if there were significant differences between and within samples. The significant differences were accepted at p ≤ 0.05. To standardize the results, overall mean of each metal from each site was calculated. The metal mean concentration values were compared with existing permissible levels set by the WHO. The concentrations (mg/kg) were in the range of 102.27 - 192.53 for Cu, Zn (131.68 - 2840.85), Pb (41.06 - 303.96), Cd (1.92 - 20.49) whereas Ni was (13.83 - 38.27) with a mean of 150.76 ± 77.88 for Copper, 131.66 ± 1598.95 for Zinc, 234.60 ± 262.76 for Lead, 12.256 ± 10.86 for Cadmium and 29.45 ± 18.24 for Nickel across the five sampling locations. There were significant differences between levels determined by one-way ANOVA of Zn (F (4, 25) = 6.893, p = 0.001, p ≤ 0.05) and Cd (F (4, 25) = 5.641, p = 0.02) and none with Cu (F (4, 25) = 1.405, p = 0.261, p ≤ 0.05), Pb (F (4, 25) = 1.073, p = 0.391, p ≤ 0.05) and Ni (F (4, 25) = 2.492, p = 0.069). Results reveal that metal content in all samples exceed the WHO permissible levels for Cu (100 mg/kg), while those for Ni were below the WHO set standards of 50 mg/kg. Levels of Zn in three hospitals exceeded permissible level of 300 mg/kg while level of Pb exceeded WHO set standards of 100 mg/kg in two hospitals. Samples from four hospitals exceeded permissible level for Cd of 3 mg/kg. This study provides evidence that incinerator bottom ash is contaminated with toxic heavy metals to human health and the environment. This study recommends that hospitals should handle the bottom ash as hazardous wastes and there is need to train and provide appropriate personal protective equipment to healthcare workers, waste handlers, and incinerator operators and enforce compliance to existing regulation and guidelines on healthcare waste management to safeguard the environment and human health.展开更多
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 ...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.展开更多
An environment friendly and cost effective factor of collapsible soilstabilization with the help of industrial waste has been widely adoptedin this research. Buildings which are constructed on collapsible soils aresub...An environment friendly and cost effective factor of collapsible soilstabilization with the help of industrial waste has been widely adoptedin this research. Buildings which are constructed on collapsible soils aresubjected to large deformations and shear failure. Collapsible soil can bebroadly categorized as those soils susceptible to a large reduction in volumeupon wetting. The mechanism usually involved in rapid volume reductionentails breaking of bonds at coarse particle contacts by weakening of finegrainedmaterials brought there by surface tension in evaporating water.This research presents the effects of using marble dust on the geotechnicalproperties of Collapsible soil as a new stabilizing technique. A series ofexperimental tests are carried for samples of collapsing soil with andwithout stabilization using marble dust for dry and soaked conditions.The collapsible soil was mixed with marble dust at different contents of(0, 10, 20, 30%,40% and50%). The results indicated that, The optimumwater content decreases by 20.67% at marble content of 50%, liquidlimit decreses by35.41% at marble content of 50%and frictional angle forsoaked soil decreases by 66.09% at marble content of 50% while un soakedsoil decreases by54.68% at marble content of 50%. The maximum drydensity increases 5.91% at marble content of 50% and cohesion for soakedincreases314.2% at marble content of 50% while un soaked soil increases206.7% at marble content of 50%. It has been found that the adoptedmarble has a good effect in controlling the collapsing potential which isreduced by as much as 64.32% at marble content of 30%.展开更多
The behavior of Beam-Column Joints in moment resisting frame structures are susceptible to damage caused by seismic effects due to poor performance of the joint.A good number of researches were carried out to understa...The behavior of Beam-Column Joints in moment resisting frame structures are susceptible to damage caused by seismic effects due to poor performance of the joint.A good number of researches were carried out to understand the complex mechanism of RC joints which are considered in seismic design code practices presently adopted.The traditional construction detailing of transverse reinforcement have shown serious joint failure. This paper introduces a new design philosophy involving the use of additional diagonal bars within the joint particularly suitable for low to medium seismic effects in earthquake zones throughout the world.In lieu to this study,ten(10) full-scale interior beam-column specimens were constructed with various additional reinforcement details and configurations as will be discussed in the later.The experiment provided adequate results to proof the idea of additional bars as suitable approach in reinforced concrete structures where earthquake is eminent.While compared with overall cracking observation during the test,the specimen with additional bars (diagonal and straight) had shown few cracks on the column than the ones without.Furthermore,concrete confinement is certainly an important design method as recommended by certain international codes.展开更多
Damped oscillation of Newtonian liquid in a vertical U-tube is one of the well known phenomena and the solution of this liquid motion for the laminar flow regime in the circular pipe was solved, however, generally spe...Damped oscillation of Newtonian liquid in a vertical U-tube is one of the well known phenomena and the solution of this liquid motion for the laminar flow regime in the circular pipe was solved, however, generally speaking, even if the period of the oscillational motion by this solution is nearly coincided with that of the experimental result, the estimation of the damped oscillational process with lapse of time by the solved equation is not in agreement with that of the experimental result. Therefore basing upon the experimental results of the velocity distributions of the oscillational motion in the circular U-tube for the Newtonian and non-Newtonian liquids, the velocity distribution of the Bingham plastic flow is assumed. The solutions of the damped oscillation and also of the vertical falling and rising velocities of the free surface in the vertical U-tube of the diameters D= 10mm, 20mm and 40mm are compared with water and water-glycerine solution for the Newtonian liquids and the acrylic co-polymer solutions for the non-Newtorlian liquid. The comparisons of these solved equations by the new flow model are shown in good agreement with the experimental results. The above stated results are described in detail.展开更多
文摘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: 4 rings), Nap (naphthalene: 2 rings), PhA (phenanthrene: 3 rings) and Pyr (pyrene: 4 rings). Ion source-interface temperature was set at 200°C - 250°C. Internal standards from Sigma Aldrich were used in the analysis and the acquired mass spectra data were then matched against the NIST 2014 library [1] [2]. The mean PAHs concentration in the bottom ashes of each hospital varied broadly from 0.001 mg/kg to 0.4845 mg/kg, and the mean total concentration levels of individual PAHs ranged from 0.0072 mg/kg to 1.171 mg/kg. Low molecular weight PAHs (Phenanthrene, Naphthalene and Fluorene) were predominant in all the hospital wastes whereas Kitale and Narok presented the lowest PAHs concentrations and the lowest number of individual PAHs. Moi/Voi recorded the highest total PAHs concentration at 1.3129 ± 0.0023 mg/kg from a total of 11 PAHs being detected from the bottom ash samples. Narok had only three PAHs being detected at very low concentrations of 0.0041 ± 0.00 mg/kg, 0.0076 ± 0.00 mg/kg and 0.012 ± 0.00 mg/kg for phenanthrene, anthracene and chrysene respectively. This study presents hospital incinerator bottom ash as containing detectable levels of both carcinogenic and non-carcinogenic PAHs. Continued unprotected exposure of hospital workers (waste handlers) to the bottom ash PAHs could be hazardous to their health because of their cumulative effect. Preventive measures e.g. the use of Personal protective equipment (PPE) should be prioritised to minimise direct contact with the bottom ash. The study recommends an upgrade on incinerator technology for efficient combustion processes thus for better pollution control.
文摘Healthcare wastes contain potentially harmful microorganisms, inorganic and organic compounds that pose a risk to human health and the environment. Incineration is a common method employed in healthcare waste management to reduce volume, quantity, toxicity as well as elimination of microorganisms. However, some of the substances remain unchanged during incineration and become part of bottom ash, such as heavy metals and persistent organic pollutants. Monitoring of pollution by heavy metals is important since their concentrations in the environment affect public health. The goal of this study was to determine the levels of Copper (Cu), Zinc (Zn) Lead (Pb), Cadmium (Cd) and Nickel (Ni) in the incinerator bottom ash in five selected County hospitals in Kenya. Bottom ash samples were collected over a period of six months. Sample preparation and treatment were done using standard methods. Analysis of the heavy metals were done using atomic absorption spectrophotometer, model AA-6200. One-Way Analysis of Variance (ANOVA) was performed to determine whether there were significant differences on the mean levels of Cu, Zn, Pd, Cd and Ni in incinerator bottom ash from the five sampling locations. A post-hoc Tukey’s Test (HSD) was used to determine if there were significant differences between and within samples. The significant differences were accepted at p ≤ 0.05. To standardize the results, overall mean of each metal from each site was calculated. The metal mean concentration values were compared with existing permissible levels set by the WHO. The concentrations (mg/kg) were in the range of 102.27 - 192.53 for Cu, Zn (131.68 - 2840.85), Pb (41.06 - 303.96), Cd (1.92 - 20.49) whereas Ni was (13.83 - 38.27) with a mean of 150.76 ± 77.88 for Copper, 131.66 ± 1598.95 for Zinc, 234.60 ± 262.76 for Lead, 12.256 ± 10.86 for Cadmium and 29.45 ± 18.24 for Nickel across the five sampling locations. There were significant differences between levels determined by one-way ANOVA of Zn (F (4, 25) = 6.893, p = 0.001, p ≤ 0.05) and Cd (F (4, 25) = 5.641, p = 0.02) and none with Cu (F (4, 25) = 1.405, p = 0.261, p ≤ 0.05), Pb (F (4, 25) = 1.073, p = 0.391, p ≤ 0.05) and Ni (F (4, 25) = 2.492, p = 0.069). Results reveal that metal content in all samples exceed the WHO permissible levels for Cu (100 mg/kg), while those for Ni were below the WHO set standards of 50 mg/kg. Levels of Zn in three hospitals exceeded permissible level of 300 mg/kg while level of Pb exceeded WHO set standards of 100 mg/kg in two hospitals. Samples from four hospitals exceeded permissible level for Cd of 3 mg/kg. This study provides evidence that incinerator bottom ash is contaminated with toxic heavy metals to human health and the environment. This study recommends that hospitals should handle the bottom ash as hazardous wastes and there is need to train and provide appropriate personal protective equipment to healthcare workers, waste handlers, and incinerator operators and enforce compliance to existing regulation and guidelines on healthcare waste management to safeguard the environment and human health.
文摘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.
文摘An environment friendly and cost effective factor of collapsible soilstabilization with the help of industrial waste has been widely adoptedin this research. Buildings which are constructed on collapsible soils aresubjected to large deformations and shear failure. Collapsible soil can bebroadly categorized as those soils susceptible to a large reduction in volumeupon wetting. The mechanism usually involved in rapid volume reductionentails breaking of bonds at coarse particle contacts by weakening of finegrainedmaterials brought there by surface tension in evaporating water.This research presents the effects of using marble dust on the geotechnicalproperties of Collapsible soil as a new stabilizing technique. A series ofexperimental tests are carried for samples of collapsing soil with andwithout stabilization using marble dust for dry and soaked conditions.The collapsible soil was mixed with marble dust at different contents of(0, 10, 20, 30%,40% and50%). The results indicated that, The optimumwater content decreases by 20.67% at marble content of 50%, liquidlimit decreses by35.41% at marble content of 50%and frictional angle forsoaked soil decreases by 66.09% at marble content of 50% while un soakedsoil decreases by54.68% at marble content of 50%. The maximum drydensity increases 5.91% at marble content of 50% and cohesion for soakedincreases314.2% at marble content of 50% while un soaked soil increases206.7% at marble content of 50%. It has been found that the adoptedmarble has a good effect in controlling the collapsing potential which isreduced by as much as 64.32% at marble content of 30%.
基金Research Institute of Structural Engineering and Seismic Disaster Prevention,Tongji University
文摘The behavior of Beam-Column Joints in moment resisting frame structures are susceptible to damage caused by seismic effects due to poor performance of the joint.A good number of researches were carried out to understand the complex mechanism of RC joints which are considered in seismic design code practices presently adopted.The traditional construction detailing of transverse reinforcement have shown serious joint failure. This paper introduces a new design philosophy involving the use of additional diagonal bars within the joint particularly suitable for low to medium seismic effects in earthquake zones throughout the world.In lieu to this study,ten(10) full-scale interior beam-column specimens were constructed with various additional reinforcement details and configurations as will be discussed in the later.The experiment provided adequate results to proof the idea of additional bars as suitable approach in reinforced concrete structures where earthquake is eminent.While compared with overall cracking observation during the test,the specimen with additional bars (diagonal and straight) had shown few cracks on the column than the ones without.Furthermore,concrete confinement is certainly an important design method as recommended by certain international codes.
文摘Damped oscillation of Newtonian liquid in a vertical U-tube is one of the well known phenomena and the solution of this liquid motion for the laminar flow regime in the circular pipe was solved, however, generally speaking, even if the period of the oscillational motion by this solution is nearly coincided with that of the experimental result, the estimation of the damped oscillational process with lapse of time by the solved equation is not in agreement with that of the experimental result. Therefore basing upon the experimental results of the velocity distributions of the oscillational motion in the circular U-tube for the Newtonian and non-Newtonian liquids, the velocity distribution of the Bingham plastic flow is assumed. The solutions of the damped oscillation and also of the vertical falling and rising velocities of the free surface in the vertical U-tube of the diameters D= 10mm, 20mm and 40mm are compared with water and water-glycerine solution for the Newtonian liquids and the acrylic co-polymer solutions for the non-Newtorlian liquid. The comparisons of these solved equations by the new flow model are shown in good agreement with the experimental results. The above stated results are described in detail.
