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Particulate matter (PM) is a major indicator of urban air quality deterioration due to its impact on human health, atmospheric visibility and climate change. However, sufficient data on personal exposure to air pollution is still rare or... more
Particulate matter (PM) is a major indicator of urban air quality deterioration due to its impact on human health, atmospheric visibility and climate change. However, sufficient data on personal exposure to air pollution is still rare or unavailable in developing countries such as Iraq. Thus, this paper investigated the personal exposure and inhalation doses of PM 1 and PM 2.5 in Al-Hillah city, Iraq, for four common motorized transportation modes, namely open windows car, closed window car, bus, and motorbike. A portable monitoring device was used to collect the data during morning and afternoon hours in two main streets in the city. A t-test examination of the obtained results showed that the mean exposure concentration for both PM 2.5 and PM 1 were significantly different in the two streets form most of the transportation modes. The difference in the means of the measured PM 1 and PM 2.5 in the morning and afternoon trips were statistically significant for all the transportation modes except for bus in 60 street. This highlights the special and temporal variation of air pollution in the city. This is largely due the deteriorated infrastructure and lack of control policies in the city. Overall, PM 2.5 and PM 1 measured exposure concentrations were higher in the morning trips than in the afternoon ones. Regardless of the time or place of measurements, closed windows cars always had the lowest exposure concentrations to PM 1 and PM 2.5. The alarming observation in this study was the high levels of PM 1 and PM 2.5 that exceeded the recommended WHO limits, and were higher than the reported concentrations in the world bank database. The study findings present preliminary data on personal exposure concentrations and inhalation doses for travelers in Al-Hillah city, which can be utilized for global studies of air contamination in countries in similar situations as Iraq and for developing local control strategies.
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The reuse of waste materials for water treatment purposes is an important approach for promoting the circular economy and achieving effective environmental remediation. This study examined the use of bone char/titanium dioxide... more
The reuse of waste materials for water treatment purposes is an important approach for promoting the circular economy and achieving effective environmental remediation. This study examined the use of bone char/titanium dioxide nanoparticles (BC/nTiO2) composite and UV for As(III) and As(V) removal from water. The composite was produced via two ways: addition of nTiO2 to bone char during and after pyrolysis. In comparison to the uncoated bone char pyrolyzed at 900 °C (BC900), nTiO2 deposition onto bone char led to a decrease in the specific surface area and pore volume from 69 to 38 m2/g and 0.23 to 0.16 cm3/g, respectively. However, the pore size slightly increased from 14 to 17 nm upon the addition of nTiO2. The composite prepared during pyrolysis (BC/nTiO2)P had better As removal than that prepared after pyrolysis with the aid of ultrasound (BC/nTiO2)US (57.3% vs. 24.8%). The composite (BC/nTiO2)P had higher arsenate oxidation than (BC/nTiO2)US by about 3.5 times. Arsenite oxidati...
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Abstract In this study, a newly developed nitrogen (N) and phosphorus (P) recovery process using a membrane contactor termed NPHarvest was tested with different liquid waste streams in large-scale trials. Ammonia was captured in ammonium... more
Abstract In this study, a newly developed nitrogen (N) and phosphorus (P) recovery process using a membrane contactor termed NPHarvest was tested with different liquid waste streams in large-scale trials. Ammonia was captured in ammonium sulfate form using a hydrophobic membrane, while phosphorus was precipitated as sludge using alkali precipitation and coagulation processes. The tested streams were selected to cover the potential liquid waste streams for nitrogen recovery and included two different mesophilic digester reject waters, landfill leachate, and separately collected urine. The NPHarvest pilot was tested with hydraulic loads in the range of 12–133 L/h. Nitrogen recovery efficiency reached a maximum of 92.5% with the reject water of mesophilic digester and a maximum ammonia flux of 481.1 mg/L.h was obtained with a urine stream. A mass transfer coefficient was calculated for the four tested wastewater streams using two different approaches, resulting in two value ranges in the order of 10−3 and 10−7 m/s. It was found that the mass transfer coefficient decreased with increase in the initial nitrogen concentration. The recovery of phosphorus varied between 79% and 97%. The quality of ammonium sulfate was evaluated by employing comprehensive tests that included vegetative cells and coliphages, harmful metals, and organic micropollutant measurements. These measurements confirmed that ammonium sulfate meets the Finnish legislation requirements for agricultural use. The use of a diluted acid wash was proven to be sufficient for maintaining membrane surface properties and was confirmed by the observed insignificant loss of hydrophobicity and the mild development of fouling. Finally, the competitiveness of NPHarvest compared to existing processes was confirmed through a detailed cost analysis.
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The interest in using natural coagulants for wastewater treatment has increased in recent years due to the environmental and health problems associated with the use of traditional coagulants. In this study, starch-based coagulants were... more
The interest in using natural coagulants for wastewater treatment has increased in recent years due to the environmental and health problems associated with the use of traditional coagulants. In this study, starch-based coagulants were tested to treat reject water produced by the dewatering of mesophilic digester sludge at the Viikinmäki wastewater treatment plant (WWTP) in Finland. The goal of this treatment is to prepare the stream for the nitrogen recovery process with membrane contactor technology. Screening tests showed that PrimePHASE 3545 was the best coagulant, and the effective dosage and pH ranges were 10-20 ml/l of the 25% diluted starch and 8-10 pH values, respectively. The process was optimized using Response Surface Methodology (RSM). The best dosage and pH combination generated by RSM was 14.1 ml/l and 9.1, respectively. In these conditions, TN, TP, TOC, SS and VSS removal percentages were 18 ± 0.57%, 80 ± 0.99%, 28 ± 1.19%, 90 ± 3.37%, and 89 ± 2.35%, respectively. However, NH3-N concentration increased by 20 ± 1.7%, mainly due to pH increase. These results held true when tested on a pilot scale at Viikinmäki WWTP in a continuous process. The sludge produced with natural coagulant was found to be of a better quality compared to that of conventional coagulants.
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Applying biochar (BC) to broad acre crops is an effective way to sequester carbon while improving soil fertility and reducing nutrient leaching. Adopting a similar approach in a hydroponic environment, BC may enhance nutrient availability... more
Applying biochar (BC) to broad acre crops is an effective way to sequester carbon while improving soil fertility and reducing nutrient leaching. Adopting a similar approach in a hydroponic environment, BC may enhance nutrient availability and reduce natural fluctuations in the nutrient solution. This study monitored the effect of BC addition to peatmoss growth media with ratios of 0%, 5%, 25% and 50% on pH, electrical conductivity (EC) and macronutrient retention, over 15 days using hydroponic nutrient solution controls. Deionised water was used to measure nutrient releases in the closed loop hydroponic system, showing that biochar increased pH level in both retention and release stages. As expected, the pH increased by a maximum of 1.5 units with the highest biochar to growth media ratio due to the natural liming nature of the BC. The EC was also affected, as BC increased in the media EC reduced. With regards to retention of nutrients, BC recovered nitrate, phosphate, calcium and s...
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Agricultural runoff is a major cause of degradation to freshwater sources. Nitrate is of particular interest, due to the abundant use of nitrogen-based fertilizers in agricultural practices globally. This study investigated the nitrate... more
Agricultural runoff is a major cause of degradation to freshwater sources. Nitrate is of particular interest, due to the abundant use of nitrogen-based fertilizers in agricultural practices globally. This study investigated the nitrate removal of biochar produced from an agricultural waste product, macadamia nutshell (MBC). Kinetic experiments and structural analyses showed that MBC pyrolsed at 900 °C exhibited inferior NO3− removal compared to that pyrolsed at 1000 °C, which was subsequently used in the column experiments. Concentrations of 5, 10 and 15 mg/L, with flowrates of 2, 5 and 10 mL/min, were examined over a 360 min treatment time. Detailed statistical analyses were applied using 23 factorial design. Nitrate removal was significantly affected by flowrate, concentration and their interactions. The highest nitrate removal capacity of 0.11 mg/g MBC was achieved at a NO3− concentration of 15 mg/L and flowrate of 2 mL/min. The more crystalline structure and rough texture of MBC...
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Research Interests: Chemistry, Fluoride, Medicine, Multidisciplinary, Adsorption, and 3 moreEnvironment, Char, and Sorbent
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In this study, the structural alteration to DOC for a range of ultrasound treatments was investigated with chemical fractionation and UV-vis spectroscopic measurement. Ultrasound treatments were applied in continuous and pulsed modes at... more
In this study, the structural alteration to DOC for a range of ultrasound treatments was investigated with chemical fractionation and UV-vis spectroscopic measurement. Ultrasound treatments were applied in continuous and pulsed modes at power levels of 48 and 84 W for effective treatment times of 5 and 15 min. Overall results show that the ultrasound treatments tended to degrade the hydrophobic aromatic fraction, while increasing the hydrophilic fraction to a lesser extent. The highest recorded reduction of hydrophobic DOC (17.8%) was achieved with pulse treatment of 84 W for15 min, while the highest increase in the hydrophilic DOC (10.5%) was obtained with continuous treatment at 84 W and 5 min. The optimal ultrasound treatment conditions were found to be pulse mode at high power and short treatment time, causing a minimal increase in the hydrophilic fraction of 1.3% with moderate removal of the hydrophobic fraction of 15.52%. The same treatment conditions, with longer treatment ti...
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The aim of this work is to identify the optimum process parameters of sonication, manosonication and thermosonication for deactivating E. coli ATCC 25922 in water-based suspension. The influence of ultrasonic intensity, frequency,... more
The aim of this work is to identify the optimum process parameters of sonication, manosonication and thermosonication for deactivating E. coli ATCC 25922 in water-based suspension. The influence of ultrasonic intensity, frequency, pressure, temperature and treatment time on the efficiency of ultrasonic treatments was investigated in this study theoretically and experimentally. The theoretical part of this study involved solving the Rayleigh-Plesset equation with different parameters and evaluating their effects on the collapse pressure of a bubble with initial radius of 0.01mm. The experimental part of the work was conducted using ultrasonic horn reactor at three levels of intensities; low (17.56 W/cm2), intermediate (21.49 W/cm2) and high (24.17 W/cm2) with fixed frequency. Thermosonication and manosonication experiments were conducted at the sub-lethal temperatures of E. coli; 45, 50, 55 and 60°C and pressures of 2, 3 and 4 bars. The optimum treatment conditions of sonication, man...
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ABSTRACT
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Membrane contactor technology affords great opportunities for nitrogen recovery from waste streams. This study presents a performance comparison between lab- and pilot-scale membrane contactors using landfill leachate samples.... more
Membrane contactor technology affords great opportunities for nitrogen recovery from waste streams. This study presents a performance comparison between lab- and pilot-scale membrane contactors using landfill leachate samples. Polypropylene (PP) and polytetrafluoroethylene (PTFE) fibers in different dimensions were compared in terms of ammonia (NH3) recovery on a lab scale using a synthetic ammonium solution. The effect of pre-treating the leachate with tannin coagulation on nitrogen recovery was also evaluated. An ammonia transfer on the lab and pilot scale was scrutinized using landfill leachate as a feed solution. It was found that PTFE fibers performed better than PP fibers. Among PTFE fibers, the most porous one (denoted as M1) had the highest NH3 flux of 19.2 g/m2.h. Tannin pre-treatment reduced fouling and increased NH3, which in turn improved nitrogen recovery. The mass transfer coefficient of the lab-scale reactor was more than double that of the pilot reactor (1.80 × 10−7 ...