Table 3 - uploaded by Richard Charles Stehouwer
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Amount of PFBC by-product applied to the Wooster, Coshocton, and Canfield soils at each lime requirement rate factor.
Source publication
Dry flue gas desulfurization (FGD) byproducts result from the removal of SO2 from the stack gases of coal-fired boilers and are mixtures of coal fly-ash, CaS04 and unspent sorbent. Dry FGD byproducts frequently have neutralizing values greater than 50% CaC03 equivalency and thus have potential for neutralizing acid agricultural soils. Owing to the...
Contexts in source publication
Context 1
... decrease in leachate S and Mg at the 32% PFBC amendment rates was apparently caused by gypsum cementing in the overburden column. Tables 3 gives leachate concentrations of elements that are of environmental concern and have been regulated with respect to land application of sewage sludge (Environmental Protection Agency 1993). Not listed are Hg and Pb. ...
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In the present study the impact of air-borne fly ash deposition was assessed in two major crops, Medicago sativa and Brassica juncea grown in the eastern parts of Gujarat. Significant effects in the morphological and biochemical parameters were observed between the affected and the unaffected plants. Shoot length decreased from 120 to 75 cm in Medi...
Experiments in the field and greenhouse were conducted in the presence of coal fly ash to determine whether gypsum can reduce Se concentration in alfalfa (Medicago sativa L.). In the field experiment, conducted at a coal fly ash landfill, 11.2 t ha-1 gypsum was applied to soil as a top dressing to test the effect of gypsum in reducing selenium (Se)...
Citations
... Leaching and/or weathering to reduce B content in FBCBAs that may induce plant toxicity have been recommended when fly ash is applied to soil (Sharma et al., 1988; Townsend and Gilliam, 1975). Boron levels were relatively high in the soil incorporation zone when mixtures of FBCBA and fly ash were added simultaneously to reduce soil acidity (Stehouwer et al., 1994). Maize grown on acid soil amended with FBCBA at 10 g kg" 1 in unleached containers (greenhouse) had reduced DM (Clark et al., 1995), and B levels in leaf tissue were sufficiently high to implicate B toxicity (R.B. ...
Fluidized bed combustion bottom ash (FBCBA) from coal burning power plants often contain substances that detrimentally affect plant growth [(e.g., boron (B)] when applied to soil. Leaf symptoms similar to B toxicity appeared when maize (Zea mays L.) was grown during Year-1 of a field experiment where FBCBA was incorporated (6,790 and 13,580 kg ha-1) in an acidic soil (Aquic Hapludult). Soil extractable B increased with increased levels of FBCBA in Year-1 and in Year-2. Although levels in Year-2 were lower than in Year-1 they were still sufficiently high to raise concern about B toxicity. Acquisition of B in leaves of maize grown in Year-1 was relatively high at the 5-leaf stage of growth, and at a normal level in the ear leaf; ear leaf B in Year-1 was greater than ear leaf B in Year-2. Grain and fodder yields of plants grown with added FBCBA were reduced in Year-1, but not in Year-2. A greenhouse study was conducted to determine leachability of B through acidic soil (Typic Hapludult) columns whose surface had been treated with FBCBA at 0, 6, and 12 g kg-1 soil and leached with different amounts of water (25, 200, and 800 mm). Maize was also grown on the leached soil columns to determine effects of compounds leached from FBCBA on growth and B acquisition in leaves. The application of 800 mm of water reduced soil levels B, and increased the amount of B leached from the columns. Maize shoot and root dry matter (DM) were enhanced with FBCBA. Increased DM associated with higher FBCBA levels may reflect increased soil pH in this acidic soil. Shoot B concentrations decreased with greater amounts of water used to leach columns. Shoot B concentrations were closely related to levels of B present in the 0-15 cm layer of soil in the column and field experiments.
... The amount of B added with the by-products was low except for the FBC and FGD+lime treatments, and most of the B added with these by-products leached from the columns (Table 2). However, increases in soil exchangeable B have been reported when B-containing CCBs were applied to soil (Stehouwer et al., 1994). ...
Application of coal combustion by-products (CCBs) to acid soils can have beneficial or detrimental effects. A column study was conducted to determine the effects of CCBs on mitigating acid soil properties after leaching with 138 cm deionized water. Columns containing 105 cm acidic Lily soil (Typic Hapludult) had mixed in the top 15 cm the following treatments (g/kg soil): no CCB or limestone (check); dolomitic limestone (lime) at 3.98; high-calcium sulfate (CaSO4) flue gas desulfurization (FGD) by-product (BP) at 15.88; combination of lime+FGD at rates given; high-CaSO4 FGD BP enriched with Mg (FGD+Mg) at 15.88; and fluidized bed combustion (FBC) BP at 6.45. After being leached for 39 days, the columns of acid soil treated with high-CaSO4 by-products showed higher subsurface pH, calcium (Ca), and sulfur (S) and lower aluminum (Al) and manganese (Mn). In contrast, the lime alone treatment had little effect on subsurface soil properties. Use of dolomitic limestone to supply magnesium (Mg) in conjunction with the CaSO4 treatments was more effective than supplementation with Mg(OH)2, where 97% of the added Mg leached from the top layer. Substances leached from the CCBs studied were effective in reducing problems associated with subsurface soil acidity.
Mining and drilling are two methods used for extracting underground fossil fuels. While mining extracts solid fossil fuels and other economically important buried solid resources by way of digging and scraping, drilling extracts liquid (e.g., conventional oil) or gaseous (e.g., natural gas) fossil fuels that are forced to flow to the earth surface. Both processes are equally hazardous and cause serious health and environmental impacts like landscape degradation, vegetation and biodiversity loss, habitat fragmentation, and generation of acid mine drainage (AMD). AMD is formed when water draining through deep mines, surface mines, and mine waste materials come in direct contact with the pyrite (iron sulfide) containing exposed rocks, causing sulfuric acid production that further dissolves other rocks, and heavy metals present in them polluting waterways and groundwater with acid, dissolve ions and heavy metals. The threats of AMD pollution continue even long after the closure of the mine and abandoned mining sites are difficult to restore without treatment due to this acidic AMD effect. Unlike mining and drilling that cause direct damage to natural ecosystems, burning coal for thermal energy produces a huge quantity of coal combustion products (CCPs), disposal of which poses another challenge. Five major types of CCPs (bottom ash; boiler slag; fly ash; fluidized bed combustion ash or FBC; flue gas desulfurization ash or FGD) are used in mine reclamation either in a single form or in various combinations. Among the different utilizations of CCPs, mine reclamation is one of the most important beneficiations as the lime content of CCPs can easily neutralize acidic water and prevent or minimize AMD. While the placement of fly ashinto deep mines give structural support to abate subsidence, placement of fly ash into surface mines or other open pits or mine overburdens help in fights against AMD as the strong packing and absorbing nature of the fly ash reduces the permeability of mine strata and divert away water from acid-generating materials. The final step of reclamation is covering the fly ash treated underground and surface mining lands with the plantations that aid in the containments of the pollutants or phytostabilize them and accelerate phytorestoration of the pre-mining habitat. Therefore, scientifically sound rehabilitation of the mines through proper phytomanagement with native plants should be designed to produce a sustainable fuelwood or bioenergy crop plantation and contribute to the prevention of climate change through encouraging clean green energy.
With the continued use of coal to generate electricity for the world's power needs, coal combustion by-products (CCPs) will be produced in greater quantities during the ensuing decades. About 130 million tons of CCPs are produced annually from the 600 coal-fired power plants currently operating in the USA, with estimates of 500 million tons produced worldwide. Five major types of CCPs exist: bottom ash; boiler slag; fly ash; fluidized bed ash; flue gas desulfurization ash. Bottom ash does not generally constitute a disposal problem because it is extensively used as aggregate fill material for construction projects, filler in construction materials (wall board and dry wall) and de-icing solids for roads. Boiler slag is used for similar purposes as bottom ash, but it can be used as a glassy grit material for sand blasting. Fly ashes constitute 70% of the by-products generated and these ashes are produced in several ways in a power plant depending on the boiler type and the emission control system employed at the power plant. These fine-textured ash materials may be dry fly ash from conventional coal-fired boilers, dry ashes collected in flue-gas desulfurization or other collection devices (bag houses or scrubber filters), or they may be collected in wet scrubber systems producing a fly ash slurry.
In the present paper, the potential use of lignite fly ash in the control of acid generation from sulphidic tailings disposed of at Lavrion, Greece was studied. Long-term laboratory column kinetic tests were performed on tailings containing 27% S, which were homogeneously mixed with various amounts of fly ash, ranging from 10 to 63% w/w. The drainage quality of the columns was monitored over a test period of 600 days. Chemical and mineralogical characterisation of column solid residues was performed after a 270-day test period. The hydraulic conductivity of the mixtures was also measured to evaluate the potential of fly ash to form a low permeability layer. Based on the results, the addition of fly ash to sulphidic tailings, even at the lower amount, increased the pH of the drainage at values of 8.6-10.0 and decreased the dissolved concentrations of contaminants, mainly Zn and Mn, to values that meet the European regulatory limits for potable water. Higher fly ash addition to tailings, at amounts of 31 and 63% w/w also reduced the water permeability of material from 1.2 x 10(-5) cm/sec to 3 x 10(-7) and 2.5 x 10(-8) m/s, respectively.
