Constructed wetlands have been applied to micro-polluted rivers and lakes. However, they often sh... more Constructed wetlands have been applied to micro-polluted rivers and lakes. However, they often show poor nitrogen removal efficiency due to insufficient carbon sources for complete denitrification in the waters. In this study, a vertical-flow wetland system was built, in which reeds as a carbon source were added in the middle layer of the substrate. Thereby, the effect of the reed carbon source on denitrification of micro-polluted rivers and lakes with a low C/N ratio in the wetland and the denitrification mechanism were studied. The results showed that the concentrations of NH 4 + -N, NO 3 --N and NO 2 --N in the effluent of the constructed wetland were reduced to 0.17-0.35, 0.20-0.49 and 0.01-0.02 mg/L after adding the reed carbon source, and the removal efficiencies of the system for NH 4 + -N and NO 3 --N reached 93.84% and 84.69%, respectively. The abundances of nirK, nirS, hzo and nrfA genes in the wetland substrate increased by 95.51%, 54.96%, 52.89% and 731.95%, respectively, which was considered to be related to the enhanced denitrification, anammox and dissimilatory nitrate reduction to ammonium of the wetland system. Reed planting promoted the increased abundances of amoA and nxrB genes, which might play a positive role in enhancing nitrification in wetland systems. The result of this study may provide a theoretical basis for the ecological restoration of low C/N micro-polluted water bodies.
Journal of Korean Society of Environmental Engineers, Dec 30, 2013
The purpose of this study is to quantify volatile organic compounds (VOCs) in gas sample using he... more The purpose of this study is to quantify volatile organic compounds (VOCs) in gas sample using headspace solid-phase microextraction (HS-SPME) coupled to GC analysis. The optimal HS-SPME conditions was CAR/PDMS fiber and 30 min absorprion time for the analysis of various VOCs. In optimal conditions, 80 VOCs could be detected within 1 ppbv and even less than 0.0005 ppbv especially in the case of BTEX. However, fiber reproducibility on adsorption efficiency was 1~9.2% (between the same fiber) and 5.9~13.5% (between the other fiber). We successfully determined 35 VOCs in landfill gas with this method and found that VOCs of high concentration are emitting from vent pipe of closed/open landfill site under the HS-SPME conditions. This method may apply to VOCs/odor determination from various atmospheric environmental samples as well as landfills.
The American Chemical Society's Division of Environmental Chemistry symposium Toward Creating a W... more The American Chemical Society's Division of Environmental Chemistry symposium Toward Creating a Water-Energy-Food (WEF) Nexus Community of Practice, brought together 25 cross-disciplinary speakers in five thematic areas: 1) state of the art models and approaches, 2) WEF Nexus initiatives and case studies, 3) WEF governance and stakeholder engagement, 4) chemical processes and WEF Nexus, 5) WEF education, community, and practice. Discussions included diverse perspectives from different areas of expertise and provided key take-home messages toward building a WEF community of practice. This paper summarizes those messages, drawing conclusions regarding the anticipated challenges and opportunities moving toward establishing a resource-nexus community of science and practice that includes the chemical societies. We define the community of science and practice as a bottom-up approach of formal and non-formal scientists, policy makers, practitioners, technology providers, and civil society members concerned with any aspect of water, energy, food, ecosystem resources allocation, management, governance, and financing. The roles of chemistry and chemical processes in understanding the interlinkages of nexus systems must not be overlooked. Chemistry plays an important role in the circularity of the food and agriculture system, and in providing cleaner energy, cleaner water, and more sustainable food production. The question is how to better engage the chemical society in the WEF nexus moving forward? The paper proposes the resource of health, highlighting major challenges and opportunities in the Water-Energy-Food-Health-Ecosystems (WEFH) Nexus, and highlights future steps for fostering dialogue among this broad, multidisciplinary, multi-stakeholder community toward establishing an inclusive community of science and practice.
The energy-consuming and carbon-intensive wastewater treatment plants could become significant en... more The energy-consuming and carbon-intensive wastewater treatment plants could become significant energy producers and recycled organic and metallic material generators, thereby contributing to broad sustainable development goals, the circular economy, and the water-energy-sanitation-food-carbon nexus. This review provides an overview of the waste(water)-based energy-extracting technologies, their engineering performance, techno-economic feasibility, and environmental benefits. Here, we propose four crucial strategies to achieve net-zero carbon along with energy sufficiency in the water sector, including (1) improvement in process energy efficiency; (2) maximizing on-site renewable capacities and biogas upgrading; (3) harvesting energy from treated effluent; (4) a new paradigm for decentralized water-energy supply units.
The impact of attrition ball-mill pretreatment on food waste particle size, soluble chemical oxyg... more The impact of attrition ball-mill pretreatment on food waste particle size, soluble chemical oxygen demand (SCOD), biochemical methane potential, and microbial community during anaerobic digestion was investigated based on milling speed and time. The uniformity of particle size improved with increasing milling speed and time. The SCOD of the pretreated samples increased to 4%, 7%, and 17% at the speeds of 150, 225, and 300 rpm, respectively, compared to the control. Milling time did not significantly change the SCOD. The cumulative methane productions of 430, 440, and 490 mL/g-VS were observed at the speeds of 150, 225, and 300 rpm, respectively, while the untreated sample exhibited the cumulative methane production of 390 mL/g-VS. Extended milling time did not improve methane production much. When the milling times of 10, 20, and 30 min were applied with the milling speed fixed at 300 rpm, the methane productions of 490, 510, and 500 mL/g-VS were observed respectively. Ball-mill pr...
In this study, continuous chemical oxygen demand (COD Mn ) and total organic carbon (TOC) analyze... more In this study, continuous chemical oxygen demand (COD Mn ) and total organic carbon (TOC) analyzers were side-by-side installed at the discharges of two different wastewater treatment plants (i.e., WWTP A and WWTP B), and operated for more than 2 months to compare their measurements. Both WWTPs A and B are receiving domestic wastewater. In general, the measurement results obtained by the COD and TOC analyzers did not show a good correlation at both sites; R2 of 0.048 for WWTP A and R2 of 0.4 for WWTP. The low R2s were attributed to the narrow ranges of data obtained by the analyzers. Therefore, the ratios between TOC and COD were calculated with the data obtained during the first 2 weeks data and were multiplied to the TOC data to predict COD values obtained for the rest of the testing days. In fact, the COD obtained by the COD analyzer and the one obtained by the prediction with the TOC analyzer matched well. They did not show statistically significant difference with the confidenc...
The odorants from wastewater sludge treated with four different chemical oxidants, i. e., potassi... more The odorants from wastewater sludge treated with four different chemical oxidants, i. e., potassium ferrate, sodium hypochlorite, sodium permanganate, and calcium nitrate, were analyzed. The release of odorants from the treated sludge was not completely eliminated, only retarded, possibly due to the low one time doseof oxidants. In a comparison of the concentration profiles of methyl mercaptan and dimethyl sulfide, calcium nitrate was the best of the four different oxidants at reducing their emission. For methyl mercaptan, calcium nitrate gave the best result, while for dimethyl sulfide, potassium permanganate was found to be the best oxidant. From this study, it was found that the oxidation-reduction potential (ORP) would be an easy and inexpensive parameter for the monitoring of the release of offensive odors.
Summary A huge amount of agricultural wastes and waste activated-sludge are being generated every... more Summary A huge amount of agricultural wastes and waste activated-sludge are being generated every year around the world. Anaerobic co-digestion (AcD) has been considered as an alternative for the utilization of organic matters from such organic wastes by producing bioenergy and biochemicals to realize a circular bioeconomy. Despite recent advancement in AcD processes, the effect of feedstock compositions and operating conditions on the biomethane production processe has not been critically explored. In this paper, we have reviewed the effects of feedstock (organic wastes) characteristics, including particle size, carbon-to-nitrogen ratio, and pretreatment options, on the performance of an anaerobic digestion process. In addition, we provided an overview of the effect of key control parameters, including retention time, temperature, pH of digestate, volatile fatty acids content, total solids content, and organic loading rate. Lastly, based on the findings from the literature, we have presented several perspectives and prospects on priority research to promote AcD to a steppingstone for a circular bioeconomy.
Methanothermobacter sp. strain THM-1, a thermophilic and hydrogenotrophic methanogen, was isolate... more Methanothermobacter sp. strain THM-1, a thermophilic and hydrogenotrophic methanogen, was isolated from an anaerobic reactor enriched with thermophilic methanogens. The genome of THM-1 shares 98.81% of its sequence with Methanothermobacter wolfeii isolate SIV6 and consists of 1,724,502 bp with 1,665 protein-coding genes, 50 noncoding RNAs, and a GC content of 48.6%.
Particulate matter (PM) pollution is of great concern for human health and vegetation. In this st... more Particulate matter (PM) pollution is of great concern for human health and vegetation. In this study, we investigated the impact of PM on primary (unifoliate) leaves of Vigna radiata (L.) R.Wilczek by exposing leaves' adaxial surface to PM. Leaves exposed to PM showed accumulation of various metal(loid)s even after removal of epicuticular wax (EW) revealing that the metals/metalloids could penetrate through the cuticular barrier. Scanning electron microscopic studies revealed that even after thorough washing with water, a significant amount (~55%) of particles were retained on the leaf surface. Leaves did not show any particles on their surface post EW removal, revealing that particles adhered to EW. Exposing primary leaves to PM did not alter their size but gave rise to smaller sized trifoliate leaves. A decline in Chl a/b of PM-exposed primary leaves suggested that PM cause a shading effect on leaves. PM-exposed primary leaves also showed a decline in sugar levels. However, the trifoliate leaves did not show any variation in Chl a/b as well as sugar levels. Our findings furnish evidence for the negative effects of PM on plants and a probable dietary exposure of humans to PMs, warranting more in-depth studies on the potential risks of PMs in agricultural sector.
Biochar is a carbon-rich material prepared from the pyrolysis of biomass under various conditions... more Biochar is a carbon-rich material prepared from the pyrolysis of biomass under various conditions. Recently, biochar drew great attention due to its promising potential in climate change mitigation, soil amendment, and environmental control. Obviously, biochar can be a beneficial soil amendment in several ways including preventing nutrients loss due to leaching, increasing N and P mineralization, and enabling the microbial mediation of N2O and CO2 emissions. However, there are also conflicting reports on biochar effects, such as water logging and weathering induced change of surface properties that ultimately affects microbial growth and soil fertility. Despite the voluminous reports on soil and biochar properties, few studies have systematically addressed the effects of biochar on the sequestration of carbon, nitrogen, and phosphorus in soils. Information on microbially-mediated transformation of carbon (C), nitrogen (N), and phosphorus (P) species in the soil environment remains r...
We live in a time of rapid change. The Covid-19 pandemic has united the world to understand and d... more We live in a time of rapid change. The Covid-19 pandemic has united the world to understand and develop solutions to protect the health and wellbeing of society. At the same time, access to information on the internet and social media has exploded. People are exposed to information with many claims. Some of the information is relevant and accurate. A significant fraction may be inaccurate, biased, and potentially dangerous. With Covid-19, the information might point to cures that are toxic or risks that are not relevant. The scientific community has developed a process to develop and convey knowledge. The validation of results and their interpretation is critical to advancing knowledge. The core of the scientific process is based on developing a hypothesisdriven concept, designing and executing an experimental approach to prove or disprove the hypothesis, conducting a statistical analysis of the results to confirm their validity, and interpreting their meaning and impact. When their work is completed the scientist prepares to publish the work. Publication requires peer review. Hypotheses, experimental approaches, results, and interpretation of results are independently and anonymously reviewed by a scientific peer. The reviewers are selected based on their expertise in the field. The peer review process is essential for the integrity of the scientific process. Without a robust scientific process, society cannot discriminate between validated results and interpretations and biased, inaccurate, and potentially dangerous conjecture. With inaccurate science society and policy makers may make poor decisions that could hurt people and the world around them.
To prevent biofouling from occurring in the cooling systems of coastal power plants, chlorine is ... more To prevent biofouling from occurring in the cooling systems of coastal power plants, chlorine is often added to the cooling water. In this study, we have evaluated the fate of the total residual oxidants and the formation of inorganic chlorination byproducts including ClO3− and ClO4− during in situ electrochlorination with seawater. Then, the results were compared with those during direct OCl−-injection to seawater. The in situ electrochlorination method based on Ti/RuO2 electrodes produced much less ClO3−, while a similar level of total residual oxidants could be achieved with a reaction time of 5 min. Moreover, no ClO4− was observed, while the direct OCl−-injection system could still result in the production of ClO4−. The less or no production of ClO3− or ClO4− by the electrochlorination of seawater was mainly attributed to two reasons. First, during the electrolysis, the less amount of OCl− is available for ClO3− formation. Secondly, the formation of ClO3− or ClO4− is affected by...
Nowadays, the water ecosystem is being polluted due to the rapid industrialization and massive us... more Nowadays, the water ecosystem is being polluted due to the rapid industrialization and massive use of antibiotics, fertilizers, cosmetics, paints, and other chemicals. Chemical oxidation is one of the most applied processes to degrade contaminants in water. However, chemicals are often unable to completely mineralize the pollutants. Enhanced pollutant degradation can be achieved by Fenton reaction and related processes. As a consequence, Fenton reactions have received great attention in the treatment of domestic and industrial wastewater effluents. Currently, homogeneous and heterogeneous Fenton processes are being investigated intensively and optimized for applications, either alone or in a combination of other processes. This review presents fundamental chemistry involved in various kinds of homogeneous Fenton reactions, which include classical Fenton, electro-Fenton, photo-Fenton, electro-Fenton, sono-electro-Fenton, and solar photoelectron-Fenton. In the homogeneous Fenton reaction process, the molar ratio of iron(II) and hydrogen peroxide, and the pH usually determine the effectiveness of removing target pollutants and subsequently their mineralization, monitored by a decrease in levels of total organic carbon or chemical oxygen demand. We present catalysts used in heterogeneous Fenton or Fenton-like reactions, such as H 2 O 2-Fe 3+ (solid)/nano-zero-valent iron/immobilized iron and electro-Fenton-pyrite. Surface properties of heterogeneous catalysts generally control the efficiency to degrade pollutants. Examples of Fenton reactions are demonstrated to degrade and mineralize a wide range of water pollutants in real industrial wastewaters, such as dyes and phenols. Removal of various antibiotics by homogeneous and heterogeneous Fenton reactions is exemplified.
Environmental Science and Pollution Research, 2017
The present study focused on the evaluation of photo-catalytic and photo-electrochemical properti... more The present study focused on the evaluation of photo-catalytic and photo-electrochemical properties of the photo-catalyst based on nickel tungstate material prepared by a nitrate method through the degradation of malachite green (MG) dye's. The effect of catalyst loading and dye concentration was examined. Physico-chemical, optical, electrical, electrochemical, and photo-electrochemical properties of the prepared material were analyzed by X-ray diffraction (XRD), fourier transforminfrared spectroscopy (FTIR), BET analysis, optical reflectance diffuse (DR), scanning electron microscopy (SEM/EDX), electrical conductivity, cyclic voltammetry (CV), current intensity, mott-shottky, and nyquist. XRD revealed the formation of monoclinic structure with a small particle size. BET surface area of the sample was around 10 m 2 /g. The results show that the degradation of MG was more than 80%, achieved after 3 h of irradiation at pH 4.6 and with a catalyst loading of 75 mg. Also, it was found that the dye photo-degradation obeyed the pseudo-first order kinetic via Langmuir Hinshelwood model. Nickel tungsten . Malachite green . Photoelectrochemical properties . Photo-degradation . Visible light Responsible editor: Suresh Pillai * A. Boudjamaa
Asian-Australasian Journal of Animal Sciences, 2007
Optimal management of indoor air quality in a confined pig house, especially in winter, is indisp... more Optimal management of indoor air quality in a confined pig house, especially in winter, is indispensable for preventing infectious respiratory disease to workers and animals. This study was performed to elucidate the correlation of aerial contaminants and climate factors in a confinement. It was observed that indoor air contaminants ion in the confinement was the highest at 2:00-5:00 pm in a day, followed by 8:00-11:00 pm and 8:00-11:00 am. This was attributed to the increase of pig activities in the afternoon. The concentration of total dust and total airborne bacteria was found to have a significant correlation with temperature and relative humidity (p<0.05). Correlation of total dust and total airborne bacteria, total dust and ammonia, and total dust and odor were shown statistically significant at 95% confidence level. In conclusion, temperature and total dust concentration correlated significantly with all the parameters except for hydrogen sulfide (H 2 S). This could be explained by the fact the dryness of pig feces by increase of interior temperature and resuspension of feed deposited on the floor by the pig activity, resulted in high generation of dust which adsorbed and carried the airborne bacteria and odor compounds in a confined pig house. It was proved that the adsorptive capacity of dust with ammonia (NH 3 ) was higher than that with hydrogen sulfide (H 2 S). (Asian-Aust.
Carbon dioxide (CO 2 ) emission reduction in industry should be a portfolio option; for example, ... more Carbon dioxide (CO 2 ) emission reduction in industry should be a portfolio option; for example, the carbon capture and utilization by mineralization (CCUM) process is a feasible and proven technology where both CO 2 capture and alkaline waste treatment occur simultaneously through an integrated approach. In this study, the challengeable barriers and significant breakthroughs of CCUM via ex-situ carbonation were reviewed from both theoretical and practical perspectives. Recent progress on the performance of various carbonation processes for different types of alkaline solid wastes was also evaluated based on CO 2 capture capacity and carbonation efficiency. Moreover, several process intensification concepts such as reactor integration and co-utilization with wastewater or brine solution were reviewed and summarized. In addition, the utilization of carbonated products from CCUM as green materials including cement, aggregate and precipitate calcium carbonate were investigated. Furthermore, the current status of worldwide CCUM demonstration projects within the ironand steelmaking industries was illustrated. The energy consumption and cost analyses of CCUM were also evaluated.
Constructed wetlands have been applied to micro-polluted rivers and lakes. However, they often sh... more Constructed wetlands have been applied to micro-polluted rivers and lakes. However, they often show poor nitrogen removal efficiency due to insufficient carbon sources for complete denitrification in the waters. In this study, a vertical-flow wetland system was built, in which reeds as a carbon source were added in the middle layer of the substrate. Thereby, the effect of the reed carbon source on denitrification of micro-polluted rivers and lakes with a low C/N ratio in the wetland and the denitrification mechanism were studied. The results showed that the concentrations of NH 4 + -N, NO 3 --N and NO 2 --N in the effluent of the constructed wetland were reduced to 0.17-0.35, 0.20-0.49 and 0.01-0.02 mg/L after adding the reed carbon source, and the removal efficiencies of the system for NH 4 + -N and NO 3 --N reached 93.84% and 84.69%, respectively. The abundances of nirK, nirS, hzo and nrfA genes in the wetland substrate increased by 95.51%, 54.96%, 52.89% and 731.95%, respectively, which was considered to be related to the enhanced denitrification, anammox and dissimilatory nitrate reduction to ammonium of the wetland system. Reed planting promoted the increased abundances of amoA and nxrB genes, which might play a positive role in enhancing nitrification in wetland systems. The result of this study may provide a theoretical basis for the ecological restoration of low C/N micro-polluted water bodies.
Journal of Korean Society of Environmental Engineers, Dec 30, 2013
The purpose of this study is to quantify volatile organic compounds (VOCs) in gas sample using he... more The purpose of this study is to quantify volatile organic compounds (VOCs) in gas sample using headspace solid-phase microextraction (HS-SPME) coupled to GC analysis. The optimal HS-SPME conditions was CAR/PDMS fiber and 30 min absorprion time for the analysis of various VOCs. In optimal conditions, 80 VOCs could be detected within 1 ppbv and even less than 0.0005 ppbv especially in the case of BTEX. However, fiber reproducibility on adsorption efficiency was 1~9.2% (between the same fiber) and 5.9~13.5% (between the other fiber). We successfully determined 35 VOCs in landfill gas with this method and found that VOCs of high concentration are emitting from vent pipe of closed/open landfill site under the HS-SPME conditions. This method may apply to VOCs/odor determination from various atmospheric environmental samples as well as landfills.
The American Chemical Society's Division of Environmental Chemistry symposium Toward Creating a W... more The American Chemical Society's Division of Environmental Chemistry symposium Toward Creating a Water-Energy-Food (WEF) Nexus Community of Practice, brought together 25 cross-disciplinary speakers in five thematic areas: 1) state of the art models and approaches, 2) WEF Nexus initiatives and case studies, 3) WEF governance and stakeholder engagement, 4) chemical processes and WEF Nexus, 5) WEF education, community, and practice. Discussions included diverse perspectives from different areas of expertise and provided key take-home messages toward building a WEF community of practice. This paper summarizes those messages, drawing conclusions regarding the anticipated challenges and opportunities moving toward establishing a resource-nexus community of science and practice that includes the chemical societies. We define the community of science and practice as a bottom-up approach of formal and non-formal scientists, policy makers, practitioners, technology providers, and civil society members concerned with any aspect of water, energy, food, ecosystem resources allocation, management, governance, and financing. The roles of chemistry and chemical processes in understanding the interlinkages of nexus systems must not be overlooked. Chemistry plays an important role in the circularity of the food and agriculture system, and in providing cleaner energy, cleaner water, and more sustainable food production. The question is how to better engage the chemical society in the WEF nexus moving forward? The paper proposes the resource of health, highlighting major challenges and opportunities in the Water-Energy-Food-Health-Ecosystems (WEFH) Nexus, and highlights future steps for fostering dialogue among this broad, multidisciplinary, multi-stakeholder community toward establishing an inclusive community of science and practice.
The energy-consuming and carbon-intensive wastewater treatment plants could become significant en... more The energy-consuming and carbon-intensive wastewater treatment plants could become significant energy producers and recycled organic and metallic material generators, thereby contributing to broad sustainable development goals, the circular economy, and the water-energy-sanitation-food-carbon nexus. This review provides an overview of the waste(water)-based energy-extracting technologies, their engineering performance, techno-economic feasibility, and environmental benefits. Here, we propose four crucial strategies to achieve net-zero carbon along with energy sufficiency in the water sector, including (1) improvement in process energy efficiency; (2) maximizing on-site renewable capacities and biogas upgrading; (3) harvesting energy from treated effluent; (4) a new paradigm for decentralized water-energy supply units.
The impact of attrition ball-mill pretreatment on food waste particle size, soluble chemical oxyg... more The impact of attrition ball-mill pretreatment on food waste particle size, soluble chemical oxygen demand (SCOD), biochemical methane potential, and microbial community during anaerobic digestion was investigated based on milling speed and time. The uniformity of particle size improved with increasing milling speed and time. The SCOD of the pretreated samples increased to 4%, 7%, and 17% at the speeds of 150, 225, and 300 rpm, respectively, compared to the control. Milling time did not significantly change the SCOD. The cumulative methane productions of 430, 440, and 490 mL/g-VS were observed at the speeds of 150, 225, and 300 rpm, respectively, while the untreated sample exhibited the cumulative methane production of 390 mL/g-VS. Extended milling time did not improve methane production much. When the milling times of 10, 20, and 30 min were applied with the milling speed fixed at 300 rpm, the methane productions of 490, 510, and 500 mL/g-VS were observed respectively. Ball-mill pr...
In this study, continuous chemical oxygen demand (COD Mn ) and total organic carbon (TOC) analyze... more In this study, continuous chemical oxygen demand (COD Mn ) and total organic carbon (TOC) analyzers were side-by-side installed at the discharges of two different wastewater treatment plants (i.e., WWTP A and WWTP B), and operated for more than 2 months to compare their measurements. Both WWTPs A and B are receiving domestic wastewater. In general, the measurement results obtained by the COD and TOC analyzers did not show a good correlation at both sites; R2 of 0.048 for WWTP A and R2 of 0.4 for WWTP. The low R2s were attributed to the narrow ranges of data obtained by the analyzers. Therefore, the ratios between TOC and COD were calculated with the data obtained during the first 2 weeks data and were multiplied to the TOC data to predict COD values obtained for the rest of the testing days. In fact, the COD obtained by the COD analyzer and the one obtained by the prediction with the TOC analyzer matched well. They did not show statistically significant difference with the confidenc...
The odorants from wastewater sludge treated with four different chemical oxidants, i. e., potassi... more The odorants from wastewater sludge treated with four different chemical oxidants, i. e., potassium ferrate, sodium hypochlorite, sodium permanganate, and calcium nitrate, were analyzed. The release of odorants from the treated sludge was not completely eliminated, only retarded, possibly due to the low one time doseof oxidants. In a comparison of the concentration profiles of methyl mercaptan and dimethyl sulfide, calcium nitrate was the best of the four different oxidants at reducing their emission. For methyl mercaptan, calcium nitrate gave the best result, while for dimethyl sulfide, potassium permanganate was found to be the best oxidant. From this study, it was found that the oxidation-reduction potential (ORP) would be an easy and inexpensive parameter for the monitoring of the release of offensive odors.
Summary A huge amount of agricultural wastes and waste activated-sludge are being generated every... more Summary A huge amount of agricultural wastes and waste activated-sludge are being generated every year around the world. Anaerobic co-digestion (AcD) has been considered as an alternative for the utilization of organic matters from such organic wastes by producing bioenergy and biochemicals to realize a circular bioeconomy. Despite recent advancement in AcD processes, the effect of feedstock compositions and operating conditions on the biomethane production processe has not been critically explored. In this paper, we have reviewed the effects of feedstock (organic wastes) characteristics, including particle size, carbon-to-nitrogen ratio, and pretreatment options, on the performance of an anaerobic digestion process. In addition, we provided an overview of the effect of key control parameters, including retention time, temperature, pH of digestate, volatile fatty acids content, total solids content, and organic loading rate. Lastly, based on the findings from the literature, we have presented several perspectives and prospects on priority research to promote AcD to a steppingstone for a circular bioeconomy.
Methanothermobacter sp. strain THM-1, a thermophilic and hydrogenotrophic methanogen, was isolate... more Methanothermobacter sp. strain THM-1, a thermophilic and hydrogenotrophic methanogen, was isolated from an anaerobic reactor enriched with thermophilic methanogens. The genome of THM-1 shares 98.81% of its sequence with Methanothermobacter wolfeii isolate SIV6 and consists of 1,724,502 bp with 1,665 protein-coding genes, 50 noncoding RNAs, and a GC content of 48.6%.
Particulate matter (PM) pollution is of great concern for human health and vegetation. In this st... more Particulate matter (PM) pollution is of great concern for human health and vegetation. In this study, we investigated the impact of PM on primary (unifoliate) leaves of Vigna radiata (L.) R.Wilczek by exposing leaves' adaxial surface to PM. Leaves exposed to PM showed accumulation of various metal(loid)s even after removal of epicuticular wax (EW) revealing that the metals/metalloids could penetrate through the cuticular barrier. Scanning electron microscopic studies revealed that even after thorough washing with water, a significant amount (~55%) of particles were retained on the leaf surface. Leaves did not show any particles on their surface post EW removal, revealing that particles adhered to EW. Exposing primary leaves to PM did not alter their size but gave rise to smaller sized trifoliate leaves. A decline in Chl a/b of PM-exposed primary leaves suggested that PM cause a shading effect on leaves. PM-exposed primary leaves also showed a decline in sugar levels. However, the trifoliate leaves did not show any variation in Chl a/b as well as sugar levels. Our findings furnish evidence for the negative effects of PM on plants and a probable dietary exposure of humans to PMs, warranting more in-depth studies on the potential risks of PMs in agricultural sector.
Biochar is a carbon-rich material prepared from the pyrolysis of biomass under various conditions... more Biochar is a carbon-rich material prepared from the pyrolysis of biomass under various conditions. Recently, biochar drew great attention due to its promising potential in climate change mitigation, soil amendment, and environmental control. Obviously, biochar can be a beneficial soil amendment in several ways including preventing nutrients loss due to leaching, increasing N and P mineralization, and enabling the microbial mediation of N2O and CO2 emissions. However, there are also conflicting reports on biochar effects, such as water logging and weathering induced change of surface properties that ultimately affects microbial growth and soil fertility. Despite the voluminous reports on soil and biochar properties, few studies have systematically addressed the effects of biochar on the sequestration of carbon, nitrogen, and phosphorus in soils. Information on microbially-mediated transformation of carbon (C), nitrogen (N), and phosphorus (P) species in the soil environment remains r...
We live in a time of rapid change. The Covid-19 pandemic has united the world to understand and d... more We live in a time of rapid change. The Covid-19 pandemic has united the world to understand and develop solutions to protect the health and wellbeing of society. At the same time, access to information on the internet and social media has exploded. People are exposed to information with many claims. Some of the information is relevant and accurate. A significant fraction may be inaccurate, biased, and potentially dangerous. With Covid-19, the information might point to cures that are toxic or risks that are not relevant. The scientific community has developed a process to develop and convey knowledge. The validation of results and their interpretation is critical to advancing knowledge. The core of the scientific process is based on developing a hypothesisdriven concept, designing and executing an experimental approach to prove or disprove the hypothesis, conducting a statistical analysis of the results to confirm their validity, and interpreting their meaning and impact. When their work is completed the scientist prepares to publish the work. Publication requires peer review. Hypotheses, experimental approaches, results, and interpretation of results are independently and anonymously reviewed by a scientific peer. The reviewers are selected based on their expertise in the field. The peer review process is essential for the integrity of the scientific process. Without a robust scientific process, society cannot discriminate between validated results and interpretations and biased, inaccurate, and potentially dangerous conjecture. With inaccurate science society and policy makers may make poor decisions that could hurt people and the world around them.
To prevent biofouling from occurring in the cooling systems of coastal power plants, chlorine is ... more To prevent biofouling from occurring in the cooling systems of coastal power plants, chlorine is often added to the cooling water. In this study, we have evaluated the fate of the total residual oxidants and the formation of inorganic chlorination byproducts including ClO3− and ClO4− during in situ electrochlorination with seawater. Then, the results were compared with those during direct OCl−-injection to seawater. The in situ electrochlorination method based on Ti/RuO2 electrodes produced much less ClO3−, while a similar level of total residual oxidants could be achieved with a reaction time of 5 min. Moreover, no ClO4− was observed, while the direct OCl−-injection system could still result in the production of ClO4−. The less or no production of ClO3− or ClO4− by the electrochlorination of seawater was mainly attributed to two reasons. First, during the electrolysis, the less amount of OCl− is available for ClO3− formation. Secondly, the formation of ClO3− or ClO4− is affected by...
Nowadays, the water ecosystem is being polluted due to the rapid industrialization and massive us... more Nowadays, the water ecosystem is being polluted due to the rapid industrialization and massive use of antibiotics, fertilizers, cosmetics, paints, and other chemicals. Chemical oxidation is one of the most applied processes to degrade contaminants in water. However, chemicals are often unable to completely mineralize the pollutants. Enhanced pollutant degradation can be achieved by Fenton reaction and related processes. As a consequence, Fenton reactions have received great attention in the treatment of domestic and industrial wastewater effluents. Currently, homogeneous and heterogeneous Fenton processes are being investigated intensively and optimized for applications, either alone or in a combination of other processes. This review presents fundamental chemistry involved in various kinds of homogeneous Fenton reactions, which include classical Fenton, electro-Fenton, photo-Fenton, electro-Fenton, sono-electro-Fenton, and solar photoelectron-Fenton. In the homogeneous Fenton reaction process, the molar ratio of iron(II) and hydrogen peroxide, and the pH usually determine the effectiveness of removing target pollutants and subsequently their mineralization, monitored by a decrease in levels of total organic carbon or chemical oxygen demand. We present catalysts used in heterogeneous Fenton or Fenton-like reactions, such as H 2 O 2-Fe 3+ (solid)/nano-zero-valent iron/immobilized iron and electro-Fenton-pyrite. Surface properties of heterogeneous catalysts generally control the efficiency to degrade pollutants. Examples of Fenton reactions are demonstrated to degrade and mineralize a wide range of water pollutants in real industrial wastewaters, such as dyes and phenols. Removal of various antibiotics by homogeneous and heterogeneous Fenton reactions is exemplified.
Environmental Science and Pollution Research, 2017
The present study focused on the evaluation of photo-catalytic and photo-electrochemical properti... more The present study focused on the evaluation of photo-catalytic and photo-electrochemical properties of the photo-catalyst based on nickel tungstate material prepared by a nitrate method through the degradation of malachite green (MG) dye's. The effect of catalyst loading and dye concentration was examined. Physico-chemical, optical, electrical, electrochemical, and photo-electrochemical properties of the prepared material were analyzed by X-ray diffraction (XRD), fourier transforminfrared spectroscopy (FTIR), BET analysis, optical reflectance diffuse (DR), scanning electron microscopy (SEM/EDX), electrical conductivity, cyclic voltammetry (CV), current intensity, mott-shottky, and nyquist. XRD revealed the formation of monoclinic structure with a small particle size. BET surface area of the sample was around 10 m 2 /g. The results show that the degradation of MG was more than 80%, achieved after 3 h of irradiation at pH 4.6 and with a catalyst loading of 75 mg. Also, it was found that the dye photo-degradation obeyed the pseudo-first order kinetic via Langmuir Hinshelwood model. Nickel tungsten . Malachite green . Photoelectrochemical properties . Photo-degradation . Visible light Responsible editor: Suresh Pillai * A. Boudjamaa
Asian-Australasian Journal of Animal Sciences, 2007
Optimal management of indoor air quality in a confined pig house, especially in winter, is indisp... more Optimal management of indoor air quality in a confined pig house, especially in winter, is indispensable for preventing infectious respiratory disease to workers and animals. This study was performed to elucidate the correlation of aerial contaminants and climate factors in a confinement. It was observed that indoor air contaminants ion in the confinement was the highest at 2:00-5:00 pm in a day, followed by 8:00-11:00 pm and 8:00-11:00 am. This was attributed to the increase of pig activities in the afternoon. The concentration of total dust and total airborne bacteria was found to have a significant correlation with temperature and relative humidity (p<0.05). Correlation of total dust and total airborne bacteria, total dust and ammonia, and total dust and odor were shown statistically significant at 95% confidence level. In conclusion, temperature and total dust concentration correlated significantly with all the parameters except for hydrogen sulfide (H 2 S). This could be explained by the fact the dryness of pig feces by increase of interior temperature and resuspension of feed deposited on the floor by the pig activity, resulted in high generation of dust which adsorbed and carried the airborne bacteria and odor compounds in a confined pig house. It was proved that the adsorptive capacity of dust with ammonia (NH 3 ) was higher than that with hydrogen sulfide (H 2 S). (Asian-Aust.
Carbon dioxide (CO 2 ) emission reduction in industry should be a portfolio option; for example, ... more Carbon dioxide (CO 2 ) emission reduction in industry should be a portfolio option; for example, the carbon capture and utilization by mineralization (CCUM) process is a feasible and proven technology where both CO 2 capture and alkaline waste treatment occur simultaneously through an integrated approach. In this study, the challengeable barriers and significant breakthroughs of CCUM via ex-situ carbonation were reviewed from both theoretical and practical perspectives. Recent progress on the performance of various carbonation processes for different types of alkaline solid wastes was also evaluated based on CO 2 capture capacity and carbonation efficiency. Moreover, several process intensification concepts such as reactor integration and co-utilization with wastewater or brine solution were reviewed and summarized. In addition, the utilization of carbonated products from CCUM as green materials including cement, aggregate and precipitate calcium carbonate were investigated. Furthermore, the current status of worldwide CCUM demonstration projects within the ironand steelmaking industries was illustrated. The energy consumption and cost analyses of CCUM were also evaluated.
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Papers by Hyunook Kim