Dielectric properties of MSWI bottom ash for non-invasive monitoring of moisture

The dielectric procperties of MSWI bottom ash as a function of volumetric water content (VWC) are reported in this paper. The objective was to aid the development of microwave based non-invasive emission monitoring and control system for various bottom ash applications. The dielectric measurements were made, on a 1.5-year-old bottom ash, with an electrical network analyzer in microwave range (300 MHz–1.5 GHz). The VWC of the samples ranged between 0.05 and 0.40 m³?m^?3. The relationship between the dielectric permittivity and the VWC was modeled with an empirical model and a physically based Birchak model (BM). The results showed that a linear relationship existed between the permittivity and the VWC at higher water contents (>0.25 m³?m^?3). However, at lower water contents (<0.25 m³?m^?3), the relationship between the permittivity and the WVC was affected by the composition of the bottom ash. The permittivity measurement, with the current method, was not affected by high salt concentrations (10 and 20 dS/m). The empirical model, as compared to BM, provided the best fit between the actual and the predicted water content. The root mean square error (RMSE) values were 0.008–0.010 and 0.06–0.09 m³?m^?3 for the empirical and the Birchak model, respectively.     

Synthesis and characterization of zeolites prepared from industrial fly ash

In this paper, we present the possibility of using fly ash to produce synthetic zeolites. The synthesis class F fly ash from the Stalowa Wola SA heat and power plant was subjected to 24 h hydrothermal reaction with sodium hydroxide. Depending on the reaction conditions, three types of synthetic zeolites were formed: Na-X (20 g fly ash, 0.5 dm³ of 3 mol?·?dm^?3 NaOH, 75 °C), Na-P1 (20 g fly ash, 0.5 dm³ of 3 mol?·?dm^?3 NaOH, 95 °C), and sodalite (20 g fly ash, 0.8 dm³ of 5 mol?·?dm^?3 NaOH?+?0.4 dm³ of 3 mol?·?dm^?3 NaCl, 95 °C). As synthesized materials were characterized to obtain mineral composition (X-ray diffractometry, Scanning electron microscopy-energy dispersive spectrometry), adsorption properties (Brunauer-Emmett-Teller surface area, N₂ isotherm adsorption/desorption), and ion exchange capacity. The most effective reaction for zeolite preparation was when sodalite was formed and the quantitative content of zeolite from X-ray diffractometry was 90 wt%, compared with 70 wt% for the Na-X and 75 wt% for the Na-P1. Residues from each synthesis reaction were the following: mullite, quartz, and the remains of amorphous aluminosilicate glass. The best zeolitic material as characterized by highest specific surface area was Na-X at almost 166 m²?·?g^?1, while for the Na-P1 and sodalite it was 71 and 33 m²?·?g^?1, respectively. The ion exchange capacity decreased in the following order: Na-X at 1.8 meq?·?g^?1, Na-P1 at 0.72 meq?·?g^?1, and sodalite at 0.56 meq?·?g^?1. The resulting zeolites are competitive for commercially available materials and are used as ion exchangers in industrial wastewater and soil decontamination.     

Investigation of heavy metal content of Turkish tobacco leaves, cigarette butt, ash, and smoke

A procedure for the determination of cadmium, copper, manganese, and zinc in Turkish tobaccos, which were of different origins, years, and grades, and in the butt, ash, and smoke, which were obtained by smoking the cigarettes that were prepared manually from the said tobaccos in a smoking apparatus, was devised as proposed. The collected samples were digested by wet ashing technique by using HNO₃-HClO₄ and were analyzed by flame atomic absorption spectrometry with satisfactory recoveries (94 % to 98 %). The regression coefficients were above 0.99, and the detection limits were in the range of 0.03–0.12 mg/L^?1. The performance and accuracy of the method was tested by analyzing “Certified Reference Material GBW 08501-Peach Leaves.” The determined values were in agreement with the standard values for the heavy metals analyzed. Thus, it was concluded that the developed method could offer a wide range of application for establishing a relationship between the makeup and composition of tobacco plant, products, ash, smoke, and smoking.     

Adsorption-desorption and leaching potential of glyphosate and aminomethylphosphonic acid in acidic Malaysian soil amended with cow dung and rice husk ash

This study investigates adsorption-desorption and the leaching potential of glyphosate and aminomethylphosphonic acid (AMPA) in control and amended—addition of cow dung or rice husk ash—acidic Malaysian soil with high oxide mineral content. The addition of cow dung or rice husk ash increased the adsorptive removal of AMPA. The isotherm data of glyphosate and AMPA best fitted the Freundlich model. The constant K_f for glyphosate was high in the control soil (544.873 mg g^?1) followed by soil with cow dung (482.451 mg g^?1) then soil with rice husk ash (418.539 mg g^?1). However, for AMPA, soil with cow dung was high (166.636 mg g^?1) followed by soil with rice husk ash (137.570 mg g^?1) then the control soil (48.446 mg g^?1). The 1/n values for both glyphosate and AMPA adsorptions were <?1 indicating their strong affinity for adsorbents. Desorption of both glyphosate and AMPA occurred only in the control soil. The compounds were not detected in soils with added cow dung or rice husk ash. The addition of cow dung or rice husk ash increased glyphosate mobility. However, ground water ubiquity scores for both control and amended soils were <?2.8. This indicated glyphosate is a transitional herbicide; therefore, its leaching potential in the soil is low, despite the addition of cow dung or rice husk ash. Addition of these wastes decreased the mobility and leaching potential of AMPA. The addition of cow dung or rice husk ash could be beneficial in increasing adsorption and enhancing degradation of these compounds.     

Serial batch leaching procedure for characterization of coal fly ash

Although many leaching methods have been used for various purposes by research groups, industries, and regulators, there is still a need for a simple but comprehensive approach to leaching coal utilization by-products and other granular materials in order to estimate potential release of heavy metals when these materials are exposed to natural fluids. A serial batch characterization method has been developed at the National Energy Technology Laboratory that can be completed in 2–3 days to serve as a screening tool. The procedure provides an estimate of cumulative metals release under varying pH conditions, and leaching the sample at increasing liquid/solid ratios can indicate the rate at which this process will occur. This method was applied to eight fly ashes, adapted to the acidic or alkaline nature of the ash. The leachates were analyzed for 30 elements. The test was run in quadruplicate, and the relative standard deviation (RSD) was used as a measure of method reproducibility. RSD values are between 0.02 and 0.70, with the majority of the RSD values less than 0.3. The serial batch leaching procedure was developed as a simple, relatively quick, yet comprehensive method of estimating the risk of heavy metal release from fly ash when it is exposed to natural fluids, such as acid rain or groundwater. Tests on a random selection of coal fly ashes have shown it to be a reasonably precise method for estimating the availability and long-term release of cations from fly ash.     

Natural attenuation of coal combustion waste in river sediments

The weathering of coal combustion products (CCPs) in a lotic environment was assessed following the Tennessee Valley Authority (Kingston, TN) fly ash release of 2008 into surrounding rivers. Sampled materials included stockpiled ash and sediment collected from 180 to 880 days following the release. Total recoverable concentrations of heavy metals and metalloids in sediment were measured, and percent ash was estimated visually or quantified by particle counts. Arsenic and selenium in sediment were positively correlated with percent ash. For samples collected 180 days after the release, total concentrations of trace elements downstream of the release were greater than reference levels but less than concentrations measured in stockpiled ash. Total concentrations of trace elements remained elevated in ash-laden sediment after almost 2.5 years. A sequential extraction procedure (SEP) was used to speciate selected fractions of arsenic, copper, lead, nickel, and selenium in decreasing order of bioavailability. Concentrations of trace elements in sequentially extracted fractions were one to two orders of magnitude lower than total recoverable trace elements. The bulk of sequentially extractable trace elements was associated with iron-manganese oxides, the least bioavailable fraction of those measured. By 780 days, trace element concentrations in the SEP fractions approached reference concentrations in the more bioavailable water soluble, ion exchangeable, and carbonate-bound fractions. For each trace element, the percentage composition of the bioavailable fractions relative to the total concentration was calculated. These SEP indices were summed and shown to significantly decrease over time. These results document the natural attenuation of leachable trace elements in CCPs in river sediment as a result of the loss of bioavailable trace elements over time.     

Immobilization of B,F, Cr,and As in alkaline coal fly ash through an aging process with water

Fourteen different alkaline coal fly ashes (CFAs) were used for the experiment, in which each sample was mixed with water to be 28.6 % of water content (wt/wt) and aged for 1–4 weeks at 10–30 °C. This simple treatment is advantageous for decreases in water-soluble B, F, Cr, and As. Compared to non-aged CFAs, their water-soluble fractions remained 0.56–88 %, 21–85 %, 0.37–93 % and 2.6–88 %, respectively, after aging for a week at 20 °C, although the amounts of Cr and As released from some CFA samples increased. Considering the significant decrease in elution of sulfate, Ca and Al after aging, the immobilization, namely prevention of toxic element elution, could be related to formation of secondary minerals such as portlandite, gypsum and ettringite. Immobilization of B and Cr tends to proceed preferentially under colder conditions. Aging at higher temperatures enhances the leachability of Cr in some CFA samples. Contrary to the behavior of B and Cr, water-soluble F effectively decreases under warmer conditions.     

Influence of mercury from fly ash on cattle reared nearby thermal power plant

Cattle grazing nearby coal-fired power stations are exposed to fly ash. The present investigation aims to assess the environmental and health impacts of fly ash containing mercury emitted from thermal power plant. The health effect of fly ash were studied using 20 lactating cattle reared within a 5-km radius of s thermal power plant for the possible effect of fly ash such as the alterations in hematological and biochemical parameters of blood, milk, and urine. Results indicated that the hemoglobin levels (6.65?±?0.40?g/dl) were significantly reduced in all the exposed animals. Biochemical parameters viz., blood urea nitrogen (27.35?±?1.19?mg/dl), serum glutamate oxaloacetate transaminase (43.39?±?3.08?IU/l), albumin, and creatinine were found to be increased, whereas serum glutamate pyruvic transaminase (29.26?±?2.02) and Ca²⁺ were observed to be statistically insignificant in exposed animals. Mercury concentrations estimated in the blood, milk, and urine of exposed (n?=?20) and control (n?=?20) animals were 7.41?±?0.86, 4.75?±?0.57, 2.08?±?0.18, and 1.05?±?0.07, 0.54?±?0.03, 0.20?±?0.02?μg/kg, respectively. The significant increase (P?<?0.01) in the levels of mercury in blood, milk, and urine of exposed animals in comparison to control indicated that the alterations of biochemical parameters in exposed cattle could be due to their long term exposure to fly ash mercury which may have direct or indirect impact on human populations via food chain.     

Changes of carbon,nitrogen, phosphorous,and potassium content during storage of vermicomposts prepared from different substrates

The study was conducted to determine the optimum storage time for vermicompost without significant loss of nutrients; nitrogen (N), phosphorous (P), and potassium (K). Cattle manure, paddy straw, municipal solid wastes, and fly ash were used for vermicompost preparations. The dynamics of N, P, and K in the vermicomposts were studied during 180 days of incubation at 28–32 °C. In general, N concentration increased in the first 90–105 days of incubation and then gradually decreased until the 180th day while P and K concentrations steadily decreased over the length of the study, with the rate of loss leveling off after 150 days. The rate of nutrient loss was directly related to the initial level, decreasing the fastest for the nutrients with the highest initial concentrations. Optimum storage times were substrate and N dependent.     

Monitoring the species of arsenic, chromium and nickel in milled coal, bottom ash and fly ash from a pulverized coal-fired power plant in western Canada

The concentration of As, Cr and Ni and their speciation (As3+;5+, Cr3+;6+ and Ni0;2+) in milled coal, bottom ash and ash collected by electrostatic precipitator (ESP) from a coal fired-power plant in western Canada were determined using HGAAS, ICP-AES and XANES. The chemical fractionation of these elements was also determined by a sequential leaching procedure, using deionized water, NH4OAC and HCI as extracting agents. The leachate was analyzed by ICP-AES. Arsenic in the milled coal is mostly associated with organic matter, and 67% of this arsenic is removed by ammonium acetate. This element is totally removed from milled coal after extraction with HCI. Arsenic occurs in both the As3+ and the As5+ oxidation states in the milled coal, while virtually all (>90%) of the arsenic in bottom ash and fly ash appears to be in the less toxic arsenate (As5+) form. Both Ni and Cr in the milled coal are extracted by HCI, indicating that water can mobilize Ni and Cr in an acidic environment. The chromium is leached by water from fly ash as a result of the high pH of the water, which is induced during the leaching. Ammonium acetate removes Ni from bottom ash through an ion exchange process. Chromium in milled coal is present entirely as Cr3+, which is an essential human trace nutrient. The Cr speciation in bottom ash is a more accentuated version of the milled coal and consists mostly of the Cr3+ species. Chromium in fly ash is mostly Cr3+, with significant contamination by stainless-steel from the installation itself.     

Comparative study of the microstructural and magnetic properties of fly ashes obtained from different thermal power plants in West Bengal, India

This paper deals with the physical nature of the fly ashes obtained from two thermal power plants, situated in West Bengal, India. The fly ash samples are characterized by using comprehensive techniques with an emphasis on their ultrafine nature. The particle sizes of the samples are estimated using scanning electron microcopy (SEM) and found to lie within 0.18–5.90 μm. For morphology and compositional analysis, we also use SEM coupled with energy dispersive X-ray spectrometry. From X-ray study of the fly ashes the nature of conglomeration is seen to be crystalline, and the major components are mullite (Al₆Si₂O₁₃) and quartz (SiO₂). The magnetic measurement of the fly ash samples was carried out by SQUID magnetometer. ⁵⁷Fe Mössbauer spectra are obtained using a conventional constant-acceleration spectrometer with a ⁵⁷Co/Rh Mössbauer source. The hyperfine parameters obtained, in general, support the findings as made from XRD analysis and provide a quantitative measure of different iron ions present in the samples. The paper presents experimental data on the physical aspects of the fly ash samples of the thermal power plants which comprise coarse, fine, and ultrafine magnetic particulate materials and attempts to provide an exhaustive analysis.     

Impact of transport and industrial emissions on the ambient air quality of Lahore City, Pakistan

This study was monitored to determine the changes in the micromineral and macromineral composition of common sole (Solea solea), striped red mullet (Mullus surmuletus), and whiting (Merlangius merlangus) throughout the year. Macromineral concentrations in edible parts of fish species were 444–1,559 mg/kg for Na, 1,975–5,130 mg/kg for K, 228–658 mg/kg for Mg, 187–1,105 mg/kg for Ca, and 2,341–7,341 for P, respectively. The highest mercury contents were found in the autumn months. While the highest protein and lowest fat values were found in the summer, the highest ash contents were found in the spring. Mercury content was found to be over the legislative limits in autumn samples for common sole and in summer for striped red mullet. Lead and cadmium contents of striped red mullet were found to be over the legislative limits throughout year.     

Effects of leachant temperature and pH on leachability of metals from fly ash. A case study: Can thermal power plant, province of Canakkale, Turkey

Lignite powered electric generation plants result in increasing environmental problems associated with gaseous emissions and the disposal of ash residues. Especially, low quality coals with high ash content cause enormous quantities of both gaseous and solid fly ash emissions. The main problem is related to the disposal of fly ash, which, in many cases, contains heavy metals. It is known that toxic trace metals may leach when fly ash is in contact with water. In this study, fly ash samples obtained from the thermal power plant in the town of Can in Turkey were investigated for leachability of metals under different acidic and temperature conditions. The experimental results show that a decrease in pH of the leachant favors the extraction of metal ions from fly ash. A significant increase in the extraction of arsenic, cadmium, chromium, zinc, lead, mercury, and selenium ions from the ash is attributed to the instability of the mineral phases. These heavy metals concentrations increase with respect to increasing acidic conditions and temperature. Peak concentrations, in general, were found at around 30°C.     

Determination of heavy metals in fresh water fish species of the River Ravi, Pakistan compared to farmed fish varieties

The untreated industrial and sewage wastes arising from industries and metropolitan activities make their passage to the River Ravi, Pakistan, where Balloki Headworks is one of the major sites of effluent concentration. This study was designed to evaluate the concentration of various toxic elements in fishes of that area compared to a nearby fish farm. The concentrations of heavy metals, such as As, Cd, Cu, Pb, Hg, and Zn, and electrolytes Ca, K, and Na were determined in different edible and non-edible fresh water fish varieties. Fish samples were collected from two selected sites and were analyzed for aforementioned elements. Higher levels of As (35.74–45.33 ppm), Cd (0.35–0.45 ppm), Pb (2.1–3.0 ppm), Hg (83.03–92.35 ppm) while normal levels of Zn (37.85–40.74 ppm) and Cu (1.39–2.93 ppm) were observed. Mercury, higher levels of which trigger cough, impairment of pulmonary function, and psychotic reactions, was significantly higher in all studied categories. At the sites under study, there has been observed alarming levels of toxic metals which are needed to be monitored regularly.     

Impact of Fly Ash from Coal-Fired Power Stations in Delhi, with Particular Reference to Metal Contamination

Indraprastha Power Station (IPP Stn) and Rajghat Power House (RPH), owned by Delhi Electric Supply Undertaking, are both coal-fired power stations located on Ring Road in New Delhi. Ash content of the coal used ranges between 38–47%. The ash is collected in electrostatic precipitators which have an efficiency of 99.3% (IPP station), and 99.7% (RPH). There are instances of major dust pollution around the power stations from fly ash dispersal. The main method of disposal of fly ash from the power stations is by mixing with water, the resultant slurry is pumped through pipes to ash disposal ponds. The supernatant from these ponds is discharged into River Yamuna. Field studies have revealed large quantities of fly ash being deposited into the river. Local populations of Eichhornia crassipes have reduced dramatically between 1987–1995, with a marked reduction in the year 1994–1995. Field studies, conducted in January, 1995 have investigated the impact of fly ash dispersal in the Delhi region with particular reference to metal contamination. Elemental concentrations for a range of elements are determined by ICP-AES in fly ash and top soils along four transects from the power stations up to a distance of 8 km. The effects of fly ash leachates from the ash settling ponds on the river are determined by analyzing river overbank soils and vegetation for their elemental contents. It is concluded that fly ash dispersal from the stacks are a source of alkali, alkaline-earth and to some extent heavy metals in soils in the vicinity of the power stations, and enrichment of elements in river overbank soils are a result of discharge of fly ash leachates from ash disposal ponds. However, the impact from both these sources of metal contamination is not large enough to give cause for concern. Marked reduction in populations of Eichhornia crassipes downstream of the river where it receives leachates from the ash disposal ponds are attributed to turbidity of the ash pond leachates and metal toxicity. Elemental enrichment in the floodplain soils, as a result of fly ash particle deposition during monsoons, may enhance the horticultural value of these soils as is shown by a healthy cultivated crop of Brassica juncea.     

Assessment and spatial distribution of groundwater quality in industrial areas of Ghaziabad, India

An attempt has been made in this study to evaluate the groundwater quality in two industrial blocks of Ghaziabad district. Groundwater samples were collected from shallow wells, deep wells and hand pumps of two heavily industrialized blocks, namely Bulandshahar road industrial area and Meerut road industrial area in Ghaziabad district for assessing their suitability for various uses. Samples were collected from 30 sites in each block before and after monsoon. They were analyzed for a total of 23 elements, namely, Ag, Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, Se, U, V, and Zn. In addition to these elements, some other parameters were also studied viz: color, odor, turbidity, biological oxygen demand, chemical oxygen demand (COD), dissolved oxygen, total dissolved solids and total suspended solid. The water quality index was also calculated based on some of the parameters estimated. Out of the 23 elements, the mean values of 12 elements, namely, Al, As, Ca, Cd, Cr, Mg, Mn, Na, Ni, Pb, Se, and U, were higher than the prescribed standard limits. The concentrations (in milligram per liter) of highly toxic metals viz., Al, As, Cd, Cr, Ni, Pb, Se, and U, ranged from 1.33–6.30, 0.04–0.54, 0.005–0.013, 4.51–7.09, 0.14–0.27, 0.13–0.32, 0.16–2.11, and 0.10–1.21, respectively, in all groundwater samples, while the permissible limits of these elements as per WHO/BIS standards for drinking are 0.2, 0.01, 0.003, 0.05, 0.07, 0.01, 0.04, and 0.03 mg L^?1, respectively. The EC, pH, and COD in all samples varied from 0.74–4.21, 6.05–7.72, and 4.5–20.0 while their permissible limits are 0.7 dS m^?1, 6.5–8.5, and 10 mg L^?1, respectively. On the basis of the above-mentioned parameters, the water quality index of all groundwater samples ranged from 101 to 491, and 871 to 2904 with mean value of 265 and 1,174 based on two criteria, i.e., physico-chemical and metal contaminations, respectively while the prescribed safe limit for drinking is below 50. The results revealed that the groundwater in the two blocks is unfit for drinking as per WHO/BIS guidelines. The presence of elements like As, Se, and U in toxic amounts is a matter of serious concern.     

Assessment of the radiological impacts of utilizing coal combustion fly ash as main constituent in the production of cement

The purpose of this study is to assess potential radiological impacts of utilizing pulverized fly ash (PFA) as a constituent in ordinary Portland cement. For this purpose, the activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K in samples of PFA and Portland cement containing 15%, 20%, and 25% by mass PFA were measured using gamma-ray spectrometry with HPGe detector. The mean activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K were found as 366.6, 113.7, and 460.2 Bq kg^???1, 94.2, 25.9, and 215.3 Bq kg^???1, 113.7, 34.3, and 238.3 Bq kg^???1, and 124.2, 41.8, and 279.3 Bq kg^???1 for the examined samples of PFA, Portland cement with 15%, 20%, and 25% by mass PFA, respectively. Radiological parameters such as radium equivalent activity, external exposure index (activity concentration index), internal dose index (alpha index), indoor absorbed gamma dose rate, and the corresponding the annually effective dose were assessed for Portland cement samples containing three percentages (15%, 20%, and 25%) by mass PFA. The results of assessment show that all Portland cement samples are within the safe limits recommended for building materials for dwellings.     

Dispersion and bioaccumulation of elements from an open-pit olivine mine in Southwest Greenland assessed using lichens, seaweeds, mussels and fish

This study investigated dispersion and bioaccumulation of mining-related elements from an open-pit olivine mine at Seqi in Southwest Greenland (64°?N) using lichens (Flavocetraria nivalis), seaweeds (Fucus vesiculosus), mussels (Mytilus edulis) and fish (Myoxocephalus scorpius). The mine operated between 2005 and 2009, and samples were taken every year within a monitoring area 0–17 km from the mine during the period 2004–2011. A total of 46 elements were analysed in the samples. After mining began, highly elevated metal concentrations, especially nickel (Ni), chromium (Cr), iron (Fe) and cobalt (Co), were observed in lichens relative to pre-mining levels (up to a factor of 130) caused by dust dispersion from the mining activity. Elevated metal concentrations could be measured in lichens in distances up to ~5 km from the mine/ore treatment facility. Moderately elevated concentrations of Ni and Cr (up to a factor of 7) were also observed in seaweeds and mussels but only in close vicinity (<1 km) to the mine. Analyses of fish showed no significant changes in element composition. After mine closure, the elevated metal concentrations in lichens, seaweeds and mussels decreased markedly, and in 2011, significantly elevated metal concentrations could only be measured in lichens and only within a distance of 1 km from the mine.