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Vertical distribution of smoke aerosols over upper Indo-Gangetic Plain

Vinjamuri KS, Mhawish A, Banerjee T, Sorek-Hamer M, Broday DM, Mall RK, et al.

Environ Pollut, 2020 Feb;257:113377.
PMID: 31672363 DOI: 10.1016/j.envpol.2019.113377

Attenuated backscatter profiles retrieved by the space borne active lidar CALIOP on-board CALIPSO satellite were used to measure the vertical distribution of smoke aerosols and to compare it against the ECMWF planetary boundary layer height (PBLH) over the smoke dominated region of Indo-Gangetic Plain (IGP), South Asia. Initially, the relative abundance of smoke aerosols was investigated considering multiple satellite retrieved aerosol optical properties. Only the upper IGP was selectively considered for CALIPSO retrieval based on prevalence of smoke aerosols. Smoke extinction was found to contribute 2-50% of the total aerosol extinction, with strong seasonal and altitudinal attributes. During winter (DJF), smoke aerosols contribute almost 50% of total aerosol extinction only near to the surface while in post-monsoon (ON) and monsoon (JJAS), relative contribution of smoke aerosols to total extinction was highest at about 8 km height. There was strong diurnal variation in smoke extinction, evident throughout the year, with frequent abundance of smoke particles at lower height (<4 km) during daytime compared to higher height during night (>4 km). Smoke injection height also varied considerably during rice (ON: 0.71 ± 0.65 km) and wheat (AM: 2.34 ± 1.34 km) residue burning period having a significant positive correlation with prevailing PBLH. Partitioning smoke AOD against PBLH into the free troposphere (FT) and boundary layer (BL) yield interesting results. BL contribute 36% (16%) of smoke AOD during daytime (nighttime) and the BL-FT distinction increased particularly at night. There was evidence that despite travelling efficiently to FT, major proportion of smoke AOD (50-80%) continue to remain close to the surface (<3 km) thereby, may have greater implications on regional climate, air quality, smoke transport and AOD-particulate modelling.

Matched MeSH terms: Coal
Urban vs. rural factors that affect adult asthma

Jie Y, Isa ZM, Jie X, Ju ZL, Ismail NH

Rev Environ Contam Toxicol, 2013;226:33-63.
PMID: 23625129 DOI: 10.1007/978-1-4614-6898-1_2

In this review, our aim was to examine the influence of geographic variations on asthma prevalence and morbidity among adults, which is important for improving our understanding, identifying the burden, and for developing and implementing interventions aimed at reducing asthma morbidity. Asthma is a complex inflammatory disease of multifactorial origin, and is influenced by both environmental and genetic factors. The disparities in asthma prevalence and morbidity among the world's geographic locations are more likely to be associated with environmental exposures than genetic differences. In writing this article, we found that the indoor factors most consistently associated with asthma and asthma-related symptoms in adults included fuel combustion, mold growth, and environmental tobacco smoke in both urban and rural areas. Asthma and asthma-related symptoms occurred more frequently in urban than in rural areas, and that difference correlated with environmental risk exposures, SES, and healthcare access. Environmental risk factors to which urban adults were more frequently exposed than rural adults were dust mites,high levels of vehicle emissions, and a westernized lifestyle.Exposure to indoor biological contaminants in the urban environment is common.The main risk factors for developing asthma in urban areas are atopy and allergy to house dust mites, followed by allergens from animal dander. House dust mite exposure may potentially explain differences in diagnosis of asthma prevalence and morbidity among adults in urban vs. rural areas. In addition, the prevalence of asthma morbidity increases with urbanization. High levels of vehicle emissions,Western lifestyles and degree of urbanization itself, may affect outdoor and thereby indoor air quality. In urban areas, biomass fuels have been widely replaced by cleaner energy sources at home, such as gas and electricity, but in most developing countries, coal is still a major source of fuel for cooking and heating, particularly in winter. Moreover, exposure to ETS is common at home or at work in urban areas.There is evidence that asthma prevalence and morbidity is less common in rural than in urban areas. The possible reasons are that rural residents are exposed early in life to stables and to farm milk production, and such exposures are protective against developing asthma morbidity. Even so, asthma morbidity is disproportionately high among poor inner-city residents and in rural populations. A higher proportion of adult residents of nonmetropolitan areas were characterized as follows:aged 55 years or older, no previous college admission, low household income, no health insurance coverage, and could not see a doctor due to healthcare service availability, etc. In rural areas, biomass fuels meet more than 70% of the rural energy needs. Progress in adopting modern energy sources in rural areas has been slow. The most direct health impact comes from household energy use among the poor, who depend almost entirely on burning biomass fuels in simple cooking devices that are placed in inadequately ventilated spaces. Prospective studies are needed to assess the long-term effects of biomass smoke on lung health among adults in rural areas.Geographic differences in asthma susceptibility exist around the world. The reason for the differences in asthma prevalence in rural and urban areas may be due to the fact that populations have different lifestyles and cultures, as well as different environmental exposures and different genetic backgrounds. Identifying geographic disparities in asthma hospitalizations is critical to implementing prevention strategies,reducing morbidity, and improving healthcare financing for clinical asthma treatment. Although evidence shows that differences in the prevalence of asthma do exist between urban and rural dwellers in many parts of the world, including in developed countries, data are inadequate to evaluate the extent to which different pollutant exposures contribute to asthma morbidity and severity of asthma between urban and rural areas.

Matched MeSH terms: Coal/adverse effects
Understanding selected trace elements behavior in a coal-fired power plant in Malaysia for assessment of abatement technologies

Mokhtar MM, Taib RM, Hassim MH

J Air Waste Manag Assoc, 2014 Aug;64(8):867-78.
PMID: 25185389

The Proposed New Environmental Quality (Clean Air) Regulation 201X (Draft), which replaces the Malaysia Environmental Quality (Clean Air) 1978, specifies limits to additional pollutants from power generation using fossil fuel. The new pollutants include Hg, HCl, and HF with limits of 0.03, 100, and 15 mg/N-m3 at 6% O2, respectively. These pollutants are normally present in very small concentrations (known as trace elements [TEs]), and hence are often neglected in environmental air quality monitoring in Malaysia. Following the enactment of the new regulation, it is now imperative to understand the TEs behavior and to assess the capability of the existing abatement technologies to comply with the new emission limits. This paper presents the comparison of TEs behavior of the most volatile (Hg, Cl, F) and less volatile (As, Be, Cd, Cr, Ni, Se, Pb) elements in subbituminous and bituminous coal and coal combustion products (CCP) (i.e., fly ash and bottom ash) from separate firing of subbituminous and bituminous coal in a coal-fired power plant in Malaysia. The effect of air pollution control devices configuration in removal of TEs was also investigated to evaluate the effectiveness of abatement technologies used in the plant. This study showed that subbituminous and bituminous coals and their CCPs have different TEs behavior. It is speculated that ash content could be a factor for such diverse behavior In addition, the type of coal and the concentrations of TEs in feed coal were to some extent influenced by the emission of TEs in flue gas. The electrostatic precipitator (ESP) and seawater flue gas desulfurization (FGD) used in the studied coal-fired power plant were found effective in removing TEs in particulate and vapor form, respectively, as well as complying with the new specified emission limits. Implications: Coals used by power plants in Peninsular Malaysia come from the same supplier (Tenaga Nasional Berhad Fuel Services), which is a subsidiary of the Malaysia electricity provider (Tenaga Nasional Berhad). Therefore, this study on trace elements behavior in a coal-fired power plant in Malaysia could represent emission from other plants in Peninsular Malaysia. By adhering to the current coal specifications and installation of electrostatic precipitator (ESP) and flue gas desulfurization, the plants could comply with the limits specified in the Malaysian Department of Environment (DOE) Scheduled Waste Guideline for bottom ash and fly ash and the Proposed New Environmental Quality (Clean Air) Regulation 201X (Draft).

Matched MeSH terms: Coal/analysis; Coal Ash/analysis*
Transformation of hazardous sacred incense sticks ash waste into less toxic product by sequential approach prior to their disposal into the water bodies

Yadav VK, Yadav KK, Alam J, Cabral-Pinto MM, Gnanamoorthy G, Alhoshan M, et al.

Environ Sci Pollut Res Int, 2023 Jun;30(28):71766-71778.
PMID: 34523099 DOI: 10.1007/s11356-021-15009-8

Incense sticks ash is one of the most unexplored by-products generated at religious places and houses obtained after the combustion of incense sticks. Every year, tonnes of incense sticks ash is produced at religious places in India which are disposed of into the rivers and water bodies. The presence of heavy metals and high content of alkali metals challenges a potential threat to the living organism after the disposal in the river. The leaching of heavy metals and alkali metals may lead to water pollution. Besides this, incense sticks also have a high amount of calcium, silica, alumina, and ferrous along with traces of rutile and other oxides either in crystalline or amorphous phases. The incense sticks ash, heavy metals, and alkali metals can be extracted by water, mineral acids, and alkali. Ferrous can be extracted by magnetic separation, while calcium by HCl, alumina by sulfuric acid treatment, and silica by strong hydroxides like NaOH. The recovery of such elements by using acids and bases will eliminate their toxic heavy metals at the same time recovering major value-added minerals from it. Here, in the present research work, the effect on the elemental composition, morphology, crystallinity, and size of incense sticks ash particles was observed by extracting ferrous, followed by extraction of calcium by HCl and alumina by H2SO4 at 90-95 °C for 90 min. The final residue was treated with 4 M NaOH, in order to extract leachable silica at 90 °C for 90 min along with continuous stirring. The transformation of various minerals phases and microstructures of incense sticks ash (ISA) and other residues during ferrous, extraction, calcium, and alumina and silica extraction was studied using Fourier transform infrared (FTIR), dynamic light scattering (DLS), X-ray fluorescence (XRF), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and inductively coupled plasma-optical emission spectroscopy (ICP-OES). DLS was used for analyzing the size during the experiments while FTIR helped in the confirmation of the formation of new products during the treatments. From the various instrumental analyses, it was found that the toxic metals present in the initial incense sticks ash got eliminated. Besides this, the major alkali metals, i.e., Ca and Mg, got reduced during these successive treatments. Initially, there were mainly irregular shaped, micron-sized particles that were dominant in the incense sticks ash particles. Besides this, there were plenty of carbon particles left unburned during combustion. In the final residue, nanosized flowers shaped along with cuboidal micron-sized particles were dominant. present in If, such sequential techniques will be applied by the industries based on recycling of incense sticks ash, then not only the solid waste pollution will be reduced but also numerous value-added minerals like ferrous, silica, alumina calcium oxides and carbonates can be recovered from such waste. The value-added minerals could act as an economical and sustainable source of adsorbent for wastewater treatment in future.

Matched MeSH terms: Coal Ash/chemistry
Fulltext Thermal Resistance Variations of Fly Ash Geopolymers: Foaming Responses

Cheng-Yong H, Yun-Ming L, Abdullah MM, Hussin K

Sci Rep, 2017 03 27;7:45355.
PMID: 28345643 DOI: 10.1038/srep45355

This paper presents a comparative study of the characteristic of unfoamed and foamed geopolymers after exposure to elevated temperatures (200-800 °C). Unfoamed geopolymers were produced with Class F fly ash and sodium hydroxide and liquid sodium silicate. Porous geopolymers were prepared by foaming with hydrogen peroxide. Unfoamed geopolymers possessed excellent strength of 44.2 MPa and degraded 34% to 15 MPa in foamed geopolymers. The strength of unfoamed geopolymers decreased to 5 MPa with increasing temperature up to 800 °C. Foamed geopolymers behaved differently whereby they deteriorated to 3 MPa at 400 °C and increased up to 11 MPa at 800 °C. Even so, the geopolymers could withstand high temperature without any disintegration and spalling up to 800 °C. The formation of crystalline phases at higher temperature was observed deteriorating the strength of unfoamed geopolymers but enhance the strength of foamed geopolymers. In comparison, foamed geopolymer had better thermal resistance than unfoamed geopolymers as pores provide rooms to counteract the internal damage.

Matched MeSH terms: Coal Ash
The influence of hazard control and prevention toward safety behaviors and safety outcomes in coal-fired power plants using PLS-SEM

Arifin K, Ali MXM, Abas A, Ahmad MA, Ahamad MA, Sahimi AS

J Safety Res, 2023 Sep;86:376-389.
PMID: 37718065 DOI: 10.1016/j.jsr.2023.07.017

INTRODUCTION: The electrical utility industry, which plays a vital role in sustaining other sectors, contributes to high occupational accident rates in the utility industries. The high accident rate shows that there has been insufficient effort made to control unsafe actions and conditions in the workplace. This study aims to examine the influence of hazard control and prevention as leading indicators of safety behaviors and outcomes in coal-fired power plants in Malaysia.
METHODS: This quantitative research was conducted by distributing survey questionnaires randomly to five coal-fired power plants in Peninsular Malaysia. A total of 340 respondents were involved in this research. Partial least squares structural equation modeling (PLS-SEM) analysis was performed using SmartPLS to validate and examine the relationship of the proposed model.
RESULTS: The results validate the construct of hazard control and prevention consisting of planning, action, managing, and verifying, while the safety outcomes construct consists of occupational accidents, fatal accidents, near misses, and lost time injuries. The results indicate that hazard control and prevention significantly relate to safety compliance, safety participation, safety motivation, and safety knowledge. Moreover, safety outcomes were influenced negatively by hazard control and prevention through safety compliance.
CONCLUSION: The model provides a better understanding of the influence of hazard control and prevention on safety behavior and outcomes.
PRACTICAL APPLICATIONS: The model can be used as guidance for practitioners and researchers in planning and implementing hazard control and prevention to improve health and safety in the workplace.

Matched MeSH terms: Coal
Fulltext The effect of different parameters on the development of compressive strength of oil palm shell geopolymer concrete

Kupaei RH, Alengaram UJ, Jumaat MZ

ScientificWorldJournal, 2014;2014:898536.
PMID: 25531006 DOI: 10.1155/2014/898536

This paper presents the experimental results of an on-going research project on geopolymer lightweight concrete using two locally available waste materials--low calcium fly ash (FA) and oil palm shell (OPS)--as the binder and lightweight coarse aggregate, respectively. OPS was pretreated with three different alkaline solutions of sodium hydroxide (NaOH), potassium hydroxide, and sodium silicate as well as polyvinyl alcohol (PVA) for 30 days; afterwards, oil palm shell geopolymer lightweight concrete (OPSGPC) was cast by using both pretreated and untreated OPSs. The effect of these solutions on the water absorption of OPS, and the development of compressive strength in different curing conditions of OPSGPC produced by pretreated OPS were investigated; subsequently the influence of NaOH concentration, alkaline solution to FA ratio (A/FA), and different curing regimes on the compressive strength and density of OPSGPC produced by untreated OPS was inspected. The 24-hour water absorption value for OPS pretreated with 20% and 50% PVA solution was about 4% compared to 23% for untreated OPS. OPSGPC produced from OPS treated with 50% PVA solution produced the highest compressive strength of about 30 MPa in ambient cured condition. The pretreatment with alkaline solution did not have a significant positive effect on the water absorption of OPS aggregate and the compressive strength of OPSGPC. The result revealed that a maximum compressive strength of 32 MPa could be obtained at a temperature of 65°C and curing period of 4 days. This investigation also found that an A/FA ratio of 0.45 has the optimum amount of alkaline liquid and it resulted in the highest level of compressive strength.

Matched MeSH terms: Coal Ash/chemistry
Fulltext The Effects of Various Concentrations of NaOH on the Inter-Particle Gelation of a Fly Ash Geopolymer Aggregate

Abdullah A, Hussin K, Abdullah MMAB, Yahya Z, Sochacki W, Razak RA, et al.

Materials (Basel), 2021 Feb 27;14(5).
PMID: 33673522 DOI: 10.3390/ma14051111

Aggregates can be categorized into natural and artificial aggregates. Preserving natural resources is crucial to ensuring the constant supply of natural aggregates. In order to preserve these natural resources, the production of artificial aggregates is beginning to gain the attention of researchers worldwide. One of the methods involves using geopolymer technology. On this basis, this current research focuses on the inter-particle effect on the properties of fly ash geopolymer aggregates with different molarities of sodium hydroxide (NaOH). The effects of synthesis parameters (6, 8, 10, 12, and 14 M) on the mechanical and microstructural properties of the fly ash geopolymer aggregate were studied. The fly ash geopolymer aggregate was palletized manually by using a hand to form a sphere-shaped aggregate where the ratio of NaOH/Na2SiO3 used was constant at 2.5. The results indicated that the NaOH molarity has a significant effect on the impact strength of a fly ash geopolymer aggregate. The highest aggregate impact value (AIV) was obtained for samples with 6 M NaOH molarity (26.95%), indicating the lowest strength among other molarities studied and the lowest density of 2150 kg/m3. The low concentration of sodium hydroxide in the alkali activator solution resulted in the dissolution of fly ash being limited; thus, the inter-particle volume cannot be fully filled by the precipitated gels.

Matched MeSH terms: Coal Ash
Fulltext Synthetic-type control charts for time-between-events monitoring

Yen FY, Chong KM, Ha LM

PLoS One, 2013;8(6):e65440.
PMID: 23755231 DOI: 10.1371/journal.pone.0065440

This paper proposes three synthetic-type control charts to monitor the mean time-between-events of a homogenous Poisson process. The first proposed chart combines an Erlang (cumulative time between events, Tr ) chart and a conforming run length (CRL) chart, denoted as Synth-Tr chart. The second proposed chart combines an exponential (or T) chart and a group conforming run length (GCRL) chart, denoted as GR-T chart. The third proposed chart combines an Erlang chart and a GCRL chart, denoted as GR-Tr chart. By using a Markov chain approach, the zero- and steady-state average number of observations to signal (ANOS) of the proposed charts are obtained, in order to evaluate the performance of the three charts. The optimal design of the proposed charts is shown in this paper. The proposed charts are superior to the existing T chart, Tr chart, and Synth-T chart. As compared to the EWMA-T chart, the GR-T chart performs better in detecting large shifts, in terms of the zero- and steady-state performances. The zero-state Synth-T4 and GR-Tr (r = 3 or 4) charts outperform the EWMA-T chart for all shifts, whereas the Synth-Tr (r = 2 or 3) and GR-T 2 charts perform better for moderate to large shifts. For the steady-state process, the Synth-Tr and GR-Tr charts are more efficient than the EWMA-T chart in detecting small to moderate shifts.

Matched MeSH terms: Coal Mining
Synergistic and sustainable utilization of coconut shell ash and groundnut shell ash in ternary blended concrete

Bheel N, Aluko OG, Khoso AR

Environ Sci Pollut Res Int, 2022 Apr;29(18):27399-27410.
PMID: 34982384 DOI: 10.1007/s11356-021-18455-6

The quest for eco-sustainable binders like agro-wastes in concrete to reduce the carbon footprint caused by cement production has been ongoing among researchers recently. The application of agro-waste-based cementitious materials in binary concrete has been said to improve concrete performance lately. Coconut and groundnut shells are available in abundant quantities and disposed of as waste in many world regions. Therefore, the use of coconut shell ash (CSA) and groundnut shell ash (GSA) in a ternary blend provides synergistic benefits with Portland cement (PC) and may be sustainably utilized in concrete as ternary cementitious material (TCM). Therefore, this study presents concrete performance with CSA and GSA in a grade 30 ternary concrete. Two hundred ten numbers of standard concrete samples were cast for checking the fresh and mechanical properties of concrete at curing ages of 7, 28, and 90 days. After 28-day curing, the experimental results show an increment in compressive, tensile, and flexural strength by 11.62%, 8.39%, and 9.46% at 10% TCM cement replacement, respectively. The concrete density and permeability coefficient reduce as TCM's content increases. The modulus of elasticity after 90 days improved with the addition of TCM. The concrete's sustainability assessment indicated that the emitted carbon for concrete decreased by around 16% using 20% TCM in concrete. However, the workability of fresh concrete declines as TCM content increases.

Matched MeSH terms: Coal Ash*
Fulltext Sustainability, Eco-Point and Engineering Performance of Different Workability OPC Fly-Ash Mortar Mixes

Razi PZ, Abdul Razak H, Khalid NHA

Materials (Basel), 2016 May 06;9(5).
PMID: 28773465 DOI: 10.3390/ma9050341

This study investigates the engineering performance and CO₂ footprint of mortar mixers by replacing Portland cement with 10%, 20%, 40% and 60% fly ash, a common industrial waste material. Samples of self-compacting mortar (SCM) were prepared with four different water/binder ratios and varying dosages of superplasticizer to give three ranges of workability, i.e., normal, high and self-compacting mortar mix. The engineering performance was assessed in term of compressive strength after designated curing periods for all mixes. CO₂ footprint was the environmental impact indicator of each production stage. The optimum mix obtained was at 10% replacement rate for all mixes. Total production emission reduced by 56% when the fly ash replacement rate increased from 0% to 60% (maximum). This is translated to a reduction of 80% in eco-points (assuming that the energy consumption rate of production with 0% fly ash is at 100%). Such re-utilization is encouraged since it is able to reduce possible soil toxicity due to sulfur leaching by 5% to 27% and landfill area by 15% to 91% on average.

Matched MeSH terms: Coal Ash
Fulltext Succession of bacterial community structure and diversity in soil along a chronosequence of reclamation and re-vegetation on coal mine spoils in China

Li Y, Wen H, Chen L, Yin T

PLoS One, 2014;9(12):e115024.
PMID: 25502754 DOI: 10.1371/journal.pone.0115024

The growing concern about the effectiveness of reclamation strategies has motivated the evaluation of soil properties following reclamation. Recovery of belowground microbial community is important for reclamation success, however, the response of soil bacterial communities to reclamation has not been well understood. In this study, PCR-based 454 pyrosequencing was applied to compare bacterial communities in undisturbed soils with those in reclaimed soils using chronosequences ranging in time following reclamation from 1 to 20 year. Bacteria from the Proteobacteria, Chloroflexi, Actinobacteria, Acidobacteria, Planctomycetes and Bacteroidetes were abundant in all soils, while the composition of predominant phyla differed greatly across all sites. Long-term reclamation strongly affected microbial community structure and diversity. Initial effects of reclamation resulted in significant declines in bacterial diversity indices in younger reclaimed sites (1, 8-year-old) compared to the undisturbed site. However, bacterial diversity indices tended to be higher in older reclaimed sites (15, 20-year-old) as recovery time increased, and were more similar to predisturbance levels nearly 20 years after reclamation. Bacterial communities are highly responsive to soil physicochemical properties (pH, soil organic matter, Total N and P), in terms of both their diversity and community composition. Our results suggest that the response of soil microorganisms to reclamation is likely governed by soil characteristics and, indirectly, by the effects of vegetation restoration. Mixture sowing of gramineae and leguminosae herbage largely promoted soil geochemical conditions and bacterial diversity that recovered to those of undisturbed soil, representing an adequate solution for soil remediation and sustainable utilization for agriculture. These results confirm the positive impacts of reclamation and vegetation restoration on soil microbial diversity and suggest that the most important phase of microbial community recovery occurs between 15 and 20 years after reclamation.

Matched MeSH terms: Coal
Fulltext Strength Development and Elemental Distribution of Dolomite/Fly Ash Geopolymer Composite under Elevated Temperature

Azimi EA, Abdullah MMAB, Vizureanu P, Salleh MAAM, Sandu AV, Chaiprapa J, et al.

Materials (Basel), 2020 Feb 24;13(4).
PMID: 32102345 DOI: 10.3390/ma13041015

A geopolymer has been reckoned as a rising technology with huge potential for application across the globe. Dolomite refers to a material that can be used raw in producing geopolymers. Nevertheless, dolomite has slow strength development due to its low reactivity as a geopolymer. In this study, dolomite/fly ash (DFA) geopolymer composites were produced with dolomite, fly ash, sodium hydroxide, and liquid sodium silicate. A compression test was carried out on DFA geopolymers to determine the strength of the composite, while a synchrotron Micro-Xray Fluorescence (Micro-XRF) test was performed to assess the elemental distribution in the geopolymer composite. The temperature applied in this study generated promising properties of DFA geopolymers, especially in strength, which displayed increments up to 74.48 MPa as the optimum value. Heat seemed to enhance the strength development of DFA geopolymer composites. The elemental distribution analysis revealed exceptional outcomes for the composites, particularly exposure up to 400 °C, which signified the homogeneity of the DFA composites. Temperatures exceeding 400 °C accelerated the strength development, thus increasing the strength of the DFA composites. This appears to be unique because the strength of ordinary Portland Cement (OPC) and other geopolymers composed of other raw materials is typically either maintained or decreases due to increased heat.

Matched MeSH terms: Coal Ash
Sources and trends of oxidized and reduced nitrogen wet deposition in a typical medium-sized city of eastern China during 2010-2016

Cui J, Cui J, Peng Y, Yao D, Chan A, Chen Z, et al.

Sci Total Environ, 2020 Jun 27;744:140558.
PMID: 32711301 DOI: 10.1016/j.scitotenv.2020.140558

Fluxes and composition dynamics of atmospheric nitrogen deposition play key roles in better balancing economic development and ecological environment. However, there are some knowledge gaps and difficulties in urban ecosystems, especially for small and medium-sized cities. In this study, both flux and composition (ratio of NH4+-N to NO3--N, RN) of wet-deposited dissolved inorganic nitrogen (DIN, sum of NO3--N and NH4+-N) were estimated and sources were identified at a long-term urban observation station in Tongling, a typical medium-sized city in eastern China during 2010-2016, respectively. Results showed that wet-deposited DIN fluxes were 33.20 and 28.15 kgN ha-1 yr-1 in Tongling city during 2010-2011 and 2015-2016, respectively. Compared to these two periods, both DIN and NO3--N fluxes decreased by 15.2% and 31.8% for a series of NOx abatement measures applied effectively, respectively. At the same time, the NH4+-N flux remained stable and ranged from 19.53 to 20.62 kgN ha-1 yr-1, and the RN increased from 1.7 to 2.2. Seasonally, winds from the southwest and west-southwest with higher frequencies and speeds in spring and summer brought more NH4+-N and DIN wet deposition from an ammonia plant, which could threaten the safety of regional hydrosphere ecosystems. On the whole, the wet-deposited NH4+-N was threatening regional ecosystems of both the hydrosphere and forest. The wet-deposited DIN including NH4+-N in Tongling city stemmed mainly from a combined source of coal combustion and dust from Cu extraction and smelting, ammonia production, and roads. Therefore, production lines should be updated for Cu extraction and smelting industries, thermal power generations and the ammonia plant, old vehicles should be eliminated, and the use of new energy vehicles should be promoted for regional sustainable development and human health in the medium-sized city.

Matched MeSH terms: Coal
Solidification and stabilization of fly ash from mixed hazardous waste incinerator using ordinary Portland cement

Pariatamby A, Subramaniam C, Mizutani S, Takatsuki H

Environ Sci, 2006;13(5):289-96.
PMID: 17096003

Fly ash samples from a mixed hazardous waste (MHW) incinerator were subjected to solidification and stabilization (S/S) studies using ordinary Portland cement (OPC) as the binder. Additives (i.e., activated carbon and rice husk) were also homogenized with the binder and waste to determine the effectiveness of the immobilization of heavy metals. The toxicity characteristics leaching procedure (TCLP), Japanese Leaching Test (JLT-13) and the American Nuclear Test 16.1 (modified) ANS 16.1 were used to gauge the leaching of heavy metals from the solidified matrixes. Compressibility strength of the solidified matrixes was also tested using the American Standard Testing Material (ASTM) test procedure for the compressive strength of hydraulic cement mortars.

Matched MeSH terms: Coal Ash
Smart solutions for clean air: An AI-guided approach to sustainable industrial pollution control in coal-fired power plant

Lim JY, Teng SY, How BS, Loy ACM, Heo S, Jansen J, et al.

Environ Pollut, 2023 Oct 15;335:122335.
PMID: 37558197 DOI: 10.1016/j.envpol.2023.122335

Conventional fossil fuels are relied on heavily to meet the ever-increasing demand for energy required by human activities. However, their usage generates significant air pollutant emissions, such as NOx, SOx, and particulate matter. As a result, a complete air pollutant control system is necessary. However, the intensive operation of such systems is expected to cause deterioration and reduce their efficiency. Therefore, this study evaluates the current air pollutant control configuration of a coal-powered plant and proposes an upgraded system. Using a year-long dataset of air pollutants collected at 30-min intervals from the plant's telemonitoring system, untreated flue gas was reconstructed with a variational autoencoder. Subsequently, a superstructure model with various technology options for treating NOx, SOx, and particulate matter was developed. The most sustainable configuration, which included reburning, desulfurization with seawater, and dry electrostatic precipitator, was identified using an artificial intelligence (AI) model to meet economic, environmental, and reliability targets. Finally, the proposed system was evaluated using a Monte Carlo simulation to assess various scenarios with tightened discharge limits. The untreated flue gas was then evaluated using the most sustainable air pollutant control configuration, which demonstrated a total annual cost, environmental quality index, and reliability indices of 44.1 × 106 USD/year, 0.67, and 0.87, respectively.

Matched MeSH terms: Coal/analysis
Fulltext Sludge-derived fuel from latex products manufacturing industry

Devaraj, V., Zairossani, M.N.

ASM Science Journal, 2012;6(1):15-21.
MyJurnal

Malaysia is the world’s top manufacturer of examination and surgical natural rubber (NR) gloves, exported mainly to the USA and Europe. The glove manufacturing process yields effluent which must be treated to comply with the stringent regulatory requirements imposed by the Malaysian Department of Environment. To make glove manufacturing an eco-friendly process, efforts are geared towards minimizing and utilizing waste or converting it into raw material for making value-added products. Waste generated from the glove industry is mainly rubber sludge which is obtained from the chemical flocculation stage of the effluent treatment process and consists of mainly rubber, remnants of compounding ingredients and water. R&D work by the Malaysian Rubber Board on waste utilization and resource recovery investigations have revealed many uses for this sludge. This paper briefly outlines only one of the many options available, which is the conversion of the sludge into sludge derived fuel (SDF). Preliminary study has identified three formulations of SDF with calorific values (CV) exceeding 16 000 kJ/kg, matching a good grade coal. This was considered as promising results which warrant explorative work for further increasing the CV of SDF to turn it into a viable fuel substitute in the latex products manufacturing industry and subsequently apply for a Clean Development Mechanism status to generate income.

Matched MeSH terms: Coal
Short-term residual characteristics of ambient-cured green geopolymer mortar exposed to elevated temperatures

Zakka WP, Lim NHAS, Khun MC, Samadi M, Aluko O, Odubela C

Environ Sci Pollut Res Int, 2024 Apr;31(17):25129-25146.
PMID: 38468004 DOI: 10.1007/s11356-024-32786-0

Every structure might be exposed to fire at some point in its lifecycle. The ability of geopolymer composites to withstand the effects of fire damage early before it is put out is of great importance. This study examined the effects of fire on geopolymer composite samples made with high-calcium fly ash and alkaline solution synthesised from waste banana peduncle and silica fume. A ratio of 0.30, 0.35, and 0.4 was used in the study for the alkaline solution to fly ash. Also used were ratios of 0.5, 0.75, and 1 for silica oxide (silica fume) to potassium hydroxide ratio. The strength loss, residual compressive strength, percentage strength loss, relative residual compressive strength, ultrasonic pulse velocity, and microstructural properties of the thirteen mortar mixes were measured after exposure to temperatures of 200, 400, 600, and 800 °C for 1 h, respectively. The results reveal that geopolymer samples exposed to elevated temperatures showed great dimensional stability with no visible surface cracks. There was a colour transition from dark grey to whitish brown for the green geopolymer mortar and brown to whitish brown for the control sample. As the temperature rose, weight loss became more pronounced, with 800 °C producing the most significant weight reduction. The optimum mixes had a residual compressive strength of 25.02 MPa after being exposed to 200 °C, 18.72 MPa after being exposed to 400 °C, 14.04 MPa after being exposed to 600 °C, and 7.41 MPa after being exposed to 800 °C. The control had a residual compressive strength of 8.45 MPa after being exposed to 200 °C, 6.67 MPa after being exposed to 400 °C, 3.16 MPa after being exposed to 600 °C, and 2.23 MPa after being exposed to 800 °C. The relative residual compressive strength decreases for green geopolymer mortar are most significant at 600 and 800 °C, with an average decrease of 0.47 and 0.30, respectively. The microstructure of the samples revealed various phase changes and new product formations as the temperature increased.

Matched MeSH terms: Coal Ash*
Short-term analysis on the combined use of sugarcane bagasse ash and rice husk ash as supplementary cementitious material in concrete production

Channa SH, Mangi SA, Bheel N, Soomro FA, Khahro SH

Environ Sci Pollut Res Int, 2022 Jan;29(3):3555-3564.
PMID: 34387820 DOI: 10.1007/s11356-021-15877-0

Globally, concrete is widely implemented as a construction material and is progressively being utilized because of growth in urbanization. However, limited resources and gradual depravity of the environment are forcing the research community to obtain alternative materials from large amounts of agro-industrial wastes as a partial replacement for ordinary cement. Cement is a main binding resource in concrete production. To reduce environmental problems associated with waste, this study considered the recycling of agro-industrial wastes, such as sugarcane bagasse ash (SCBA), rice husk ash (RHA), and others, into cement, and to finally bring sustainable and environmental-friendly concrete. This study considered 5%, 10%, and 15% of SBCA and RHA individually to replace ordinary Portland cement (OPC) by weight method then combined both ashes as 10%, 20%, and 30% to replace OPC to produce sustainable concrete. It was experimentally declared that the strength performance of concrete was reduced while utilizing SCBA and RHA individually and combined as supplementary cementitious material (SCM) at 7, 28, 56, and 90 days, respectively. Moreover, the initial and final setting time is increased as the quantity of replacement level of OPC with SCBA and RHA separates and together as SCM in the mixture. Based on experimental findings, it was concluded that the use of 5% of SCBA and 5% of RHA as cement replacement material individually or combined in concrete could provide appropriate results for structural applications in concrete.

Matched MeSH terms: Coal Ash
Seasonal fluxes and sources apportionment of dissolved inorganic nitrogen wet deposition at different land-use sites in the Three Gorges reservoir area

Cui J, Zhang Y, Yang F, Chang Y, Du K, Chan A, et al.

Ecotoxicol Environ Saf, 2020 Apr 15;193:110344.
PMID: 32092583 DOI: 10.1016/j.ecoenv.2020.110344

To identify seasonal fluxes and sources of dissolved inorganic nitrogen (DIN) wet deposition, concentrations and δ15N signatures of nitrate (NO3-) and ammonium (NH4+) in wet precipitation were measured at four typical land-use types in the Three Gorges reservoir (TGR) area of southwest China for a one-year period. Higher DIN fluxes were recorded in spring and summer and their total fluxes (averaged 7.58 kg N ha-1) were similar to the critical loads in aquatic ecosystems. Significant differences of precipitation δ15N were observed for NH4+-N between town and wetland sites in spring and between urban and rural sites in summer. For NO3--N, significant differences of precipitation δ15N were observed between town and rural sites in spring and between urban and town sites in autumn, respectively. Quantitative results of NO3--N sources showed that both biomass burning and coal combustion had higher fluxes at the urban site especially in winter (0.18 ± 0.09 and 0.19 ± 0.08 kg N ha-1), which were about three times higher than those at the town site. A similar finding was observed for soil emission and vehicle exhausts in winter. On the whole, DIN wet deposition averaged at 12.13 kg N ha-1 yr-1 with the urban site as the hotspot (17.50 kg N ha-1 yr-1) and regional NO3--N fluxes had a seasonal pattern with minimum values in winter. The contribution to NO3--N wet deposition from biomass burning was 26.1 ± 14.1%, which is the second dominant factor lower than coal combustion (26.5 ± 12.6%) in the TGR area during spring and summer. Hence N emission reduction from biomass burning, coal combustion and vehicle exhausts should be strengthened especially in spring and summer to effectively manage DIN pollution for the sustainable development in TGR area.

Matched MeSH terms: Coal

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