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1.
The impact of plants (Phalaris arundinacea L.) on the leakage of ammonium, cadmium, copper, nitrate, phosphate, and zinc from sulfidic mine tailings covered with wood fly ash and sewage sludge was investigated. Either ash or sludge was placed in contact with the tailings, and ash layers of either low or high compactness were used. It was revealed that an ash/sludge cover effectively decreased the metal leaching from the tailings regardless of the order in which the materials were applied. Plants decreased the amount of leachate and the concentrations of ammonium and phosphate. The presence of ash below the sludge decreased the plant uptake of copper and zinc and nitrate leakage. However, when the ash was added as a thin (1.5 cm) porous layer, roots and air reached the tailings and caused high metal leakage. The results support the use of a vegetated ash/sludge cover in the treatment of mine tailings, provided that the sealing layer is firm enough to prevent root penetration. 相似文献
2.
Lovisa Stjernman Forsberg Jon-Petter Gustafsson Dan Berggren Kleja Stig Ledin 《Water, air, and soil pollution》2008,194(1-4):331-341
A 20-month column experiment investigated leaching of Al, Cu, Mn, Ni, Zn, Cd and Pb during sulphide oxidation in mine tailings with and without sewage sludge (SS) amendment. Leachate pH decreased gradually in all columns during the experiment, irrespective of treatment, due to sulphide oxidation. As the degree of sulphide oxidation, and thus the pH trajectory, differed between replicates (n?=?3), running data for each column used are reported separately and the relationships between sulphide oxidation, metal leaching and treatment in each column compared. Mean pH in the columns correlated negatively with total amounts of leached SO4 2-. In the beginning of the experiment the leachate concentrations of Al, Cu, Zn, Ni and Pb were higher in SS-treated columns due to high initial concentrations of dissolved organic carbon. As leaching proceeded, however, the amounts of Al, Cu, Mn and Ni leached from the columns were closely related to the degree of sulphide oxidation in each column, i.e. to its mean pH. There were no statistically significant differences between treatments regarding the total amounts of metals leached and thus addition of sewage sludge to the tailings appeared to play a minor role for metal leaching patterns. Peak concentrations of Al and Cu in the leachate from untreated tailings and of Zn in the leachate from both untreated and SS-treated tailings at pH 4 exceeded national background values for groundwater. 相似文献
3.
《Communications in Soil Science and Plant Analysis》2012,43(5-6):469-488
Abstract Different admixtures of soil, paper mill sludge and fly ash were evaluated in greenhouse and field experiments as a final cover for landfills. The admixtures and three grass legume mixtures were evaluated for germination, plant height, biomass production, and root penetration. Admixtures with equal parts soil, sludge and fly ash and with three parts sludge, one part fly ash and one pan soil performed the best in the greenhouse experiment. Heavy metal translocation was not a problem in the admixtures because of the high pH and low metal concentrations. 相似文献
4.
Agronomic use of coal combustion by-products is often associated with boron (B) excess in amended soils and subsequently in plants. A greenhouse study with corn (Zea mays L.) as test plant was conducted to determine safe application rates of five fly ashes and one flue gas desulfurization gypsum (FDG). All by-products increased soil and corn tissue B concentration, in some cases above toxicity levels which are 5 mg hot water soluble B (hwsB) kg?1 soil and 100 mg B kg?1 in corn tissue. Acceptable application rates varied from 4 to 100 Mg ha? for different by-products. Leaching and weathering of a high B fly ash under ponding conditions decreased its B content and that of corn grown in fly ash amended soil, while leaching of the same fly ash under laboratory conditions increased fly ash B availability to corn in comparison to the fresh fly ash. Hot water soluble B in fly ash or FDG amended soil correlated very well with corn tissue B. Hot water soluble B in fly ash amended soil could be predicted based on soil pH and B solubility in ash at different pH values but not so in the case of FDG. Another greenhouse study was conducted to compare the influence of FDG and Ca(OH)2 on B concentration in spinach (Spinacia oleracea L.) leaves grown in soil amended with the high B fly ash. The Ca(OH)2 significantly decreased tissue B content, while FDG did not affect B uptake from fly ash amended soil. 相似文献
5.
Arsenate Displacement from Fly Ash in Amended Soils 总被引：1，自引：0，他引：1
Qafoku Nikolla P. Kukier Urszula Sumner Malcolm E. Miller William P. Radcliffe David E. 《Water, air, and soil pollution》1999,114(1-2):185-198
Arsenic (As) is the biggest environment contaminant in most of the soils where fly ash is applied. Usually, it is not mobile and strongly adsorbed on to soil particles. However, in gypsum and phosphorus amended soils As may be much more mobile. A study in repacked columns was conducted to determine whether or not As becomes mobile when Ca(H2PO4)2and CaSO4are used as leaching solutions, and to compare the competitive interactions between PO4-AsO4and SO4-AsO4. Arsenic concentration in leachate was found to be approximately ten times greater when Ca(H2PO4)2was used to leach the columns as compared to CaSO4. A maximum concentration of 800 μg As L-1was found in the leachate in this case, which is much higher than the groundwater limit of 50 μg L-1for drinking water established by the United States Environmental Protection Agency. In fly ash, the portion of arsenate non-specifically adsorbed is believed to be much lower than that of specifically adsorbed. Sulfate anions were able to displace only non-specifically adsorbed arsenate. In this case the concentration of As in leachate was found to be within acceptable limits. On the other hand, phosphate can compete with arsenate for all available adsorption sites, non-specific and specific. Phosphate displacement of both forms of arsenates increases As mobility in both control and fly ash treatments. 相似文献
6.
An old lead mine tailings pile in Southeast Missouri is being used as a sanitary landfill. The tailings were found to consist of 60–70% dolomite, 20–30% mascovite/illite and trace amounts of quartz, galena, and calcite. The pH was 8.1 and the lead concentrations were 810-3200 mg/kg. Several samples at the site were found hazardous using the EPA toxicity characteristic leaching procedure (TCLP). Since little was known about the mobility of the lead under these conditions, laboratory scale column experiments were conducted to determine if the lead in the tailings might be mobilized with a landfill leachate. Total lead was determined and lead availability was determined using sequential extraction. The lead associated with Fractions 1 (MgC12), 2 (NH4OAc), and 3 (Na4P2O7) of the sequential extraction leached rapidly and immediately produced a leachate after 1 hr of 440 mg/L before decreasing to 40 mg/L after 12 hr. Fraction 4 (EDTA) and Fraction 5 (HNO3), were unaffected by the leachate. 相似文献
7.
Five raised-bed test plots were used to study the effects of cover materials on the leaching of constituents from dolomitic Pb mine tailings over a 2-yr period. The cover materials studied were a fertilizer and seed mixture, anaerobically digested sewage sludge, loam and sod, and fallen leaves from silver maples (Acer Saccharinum); one plot was not covered. Fresh leachates and receiving pool waters were analyzed for ten metals, Si, P, inorganic anions, filterable organic carbon (FOC), and alkalinity. The mixture of fertilizer and seed decreased leaching of Pb and Zn during the first year. The leaf cover increased leaching of Pb during both years; this effect decreased as the leaves weathered. Sludge caused some increase in Pb leaching during the first year, and increased Cd leaching during both years. Concentrations of most leachate constituents decreased, and pH increased in the receiving pools. Concentrations of Pb remained higher in the receiving pool for the leaf-covered plot than in the other pools. Increases in leaching of Pb and Cd with a sludge cover were moderate, and the ability of the material to support plant growth on the tailings suggested that it may be a good medium for inducing growth of vegetative cover on the dolomitic tailings. Other organic materials may cause pronounced increase in the concentration of toxic trace metals in leachate from the tailings. 相似文献
8.
The influences of fly ash and fly‐ash–quicklime‐treated‐sludge mixtures (with fly‐ash doses of 40%, 80%, and 120% on dry‐weight basis) on the microbial numbers in soil and leachate were investigated by using 60 cm soil columns. Heterotrophic bacteria and total coliform numbers were determined in soil and leachate samples following an artificial rainfall event. The results indicated that land application of untreated sludge and fly‐ash–sludge mixtures appear to introduce large numbers of bacteria to leachates and soil. Although the numbers in leachates and soils were found to decrease with increasing ash ratios, they were still all significantly above the control levels. Application of alkaline‐stabilized and pasteurized sludge did not increase bacterial numbers significantly in soil and leachate. Distribution of heterotrophic bacteria through soil profile clearly showed no increase in soils amended with alkaline‐stabilized and pasteurized sludges. Additionally, no significant inhibitory effect of lignite fly ash on soil microbial population was observed. 相似文献
9.
A greenhouse and laboratory study was undertaken to quantify the P-sorption capacity of high pH, high calcium, coal-combustion, waste materials and determine the amount of P fertilization necessary to overcome that P-sorption ability. Three different waste materials (bottom ash, bottom ash/fly ash mixture, and bottom ash/scrubber sludge mixture) were selected based upon their handling properties and their ability to support plant growth. A steady state was apparently established within 18 hr after adding P. Phosphorus sorption behavior was typical of precipitation rather than surface adsorption for all ash materials. The combination of high pH and readily available Ca in the bottom ash and bottom/fly ash mixture favored rapid precipitation of calcium phosphates. The β-tricalcium phosphate that apparently formed in these materials would not provide adequate P for plant growth, and fertilizing with more than 1000 kg P ha?1 would be necessary to provide the needed concentrations. The calcareous bottom ash/sludge mixture would maintain a sufficient P concentration to support plant growth because of its relatively low pH. As leaching and exposure to CO2(g) proceed in the other two ash materials, equilibrium with calcite would be established and P fixing would be a smaller hindrance to plant growth. 相似文献
10.
The adsorption capacity of seven inorganic solid wastes [air-cooled blast furnace (BF) slag, water-quenched BF slag, steel furnace slag, coal fly ash, coal bottom ash, water treatment (alum) sludge and seawater-neutralized red mud] for Cd2+, Cu2+, Pb2+, Zn2+ and Cr3+ was determined at two metal concentrations (10 and 100 mg?L?1) and three equilibrium pH values (4.0, 6.0 and 8.0) in batch adsorption experiments. All materials had the ability to remove metal cations from aqueous solution (fly and bottom ash were the least effective), their relative abilities were partially pH dependant and adsorption increased greatly with increasing pH. At equimolar concentrations of added metal, the magnitude of sorption at pH 6.0 followed the general order: Cr3+????Pb2+????Cu2+?>?Zn2+?=?Cd2+. The amounts of previously sorbed Pb and Cd desorbed in 0.01 M NaNO3 electrolyte were very small, but those removed with 0.01 M HNO3, and more particularly 0.10 M HNO3, were substantial. Water treatment sludge was shown to maintain its Pb and Cd adsorption capability (pH 6.0) over eight successive cycles of adsorption/regeneration using 0.10 M HNO3 as a regenerating agent. By contrast, for BF slag and red mud, there was a very pronounced decline in adsorption of both Pb and Cd after only one regeneration cycle. A comparison of Pb and Cd adsorption isotherms at pH 6.0 for untreated and acid-pre-treated materials confirmed that for water treatment sludge acid pre-treatment had no significant effect, but for BF slag and red mud, adsorption was greatly reduced. This was explained in terms of residual surface alkalinity being the key factor contributing to the high adsorption capability of the latter two materials, and acid pre-treatment results in neutralization of much of this alkalinity. It was concluded that acid is not a suitable regenerating agent for slags and red mud and that further research and development with water treatment sludge as a metal adsorbent are warranted. 相似文献
11.
Retention of Cd, Cu, Pb and Zn by Wood Ash, Lime and Fume Dust 总被引：2，自引：0，他引：2
Heavy metals are of interest due to their deleterious impacts on both human and ecosystem health. This study investigated the effectiveness of wood ash in immobilizing the heavy metals Pb, Cd, Cu and Zn from aqueous solutions. The effects of initial metal concentrations, solution pH, ash dose and reaction time on metal sorption, as well as the metal sorption mechanisms were studied. To investigate the effect of initial metal concentrations, solutions containing Cd, Zn (25, 50, 75, 100 or 125 mg L?1), Cu (25, 50, 75, 100, 125, 150 or 175 mg L?1) or Pb (250, 500, 750, 1000, 1250, or 1500 mg L?1) were reacted with 10 g L?1 ash for two hours. For the effect of pH, solutions containing 100 mg L?1 of Cd, Cu or Zn or 1500 mg L?1 of Pb were reacted with 15 g L?1 ash over a pH range of 4 to 7. The wood ash was effective in immobilizing the four metals with a sorption range of 41–100 %. The amounts of metals retained by the ash followed the order of Pb > Cu > Cd > Zn. As expected, absolute metal retention increased with increasing initial metal concentrations, solution pH and ash dose. Metal retention by the ash exhibited a two-phase step: an initial rapid uptake of the metal followed by a period of relatively slow removal of metal from solution. Metal retention by the ash could be described by the Langmuir and Freundlich isotherms, with the latter providing a better fit for the data. Dissolution of calcite /gypsum minerals and precipitation of metal carbonate/sulfate like minerals were probably responsible for metal immobilization by the ash in addition to adsorption. 相似文献
12.
Major impediments to the land application of coal combustion byproducts (fly ash) for crop fertilization have been the presence of heavy metals and their relatively low and imbalanced essential nutrient concentration. Although nutrient deficiencies, in particular N, P, and K, may be readily augmented by adding organic wastes such as sewage sludge and animal manure, the indiscriminate application of mixtures to crops can cause excessive soil alkalinity, imbalanced nutrition (P, Mg), phytotoxicities (B, Mn, ammonia, nitrite), and unspecified contamination of the food chain by elements such as As. In this study, nutrient availability data and linear programming (LP) were used to solve these problems by formulating fly ash-biosolid triple mixtures which complied with both plant and soil fertilization requirements, and met existing U.S.A. environmental regulations for total As application in sewage sludge (EPA-503). Thirteen different fly ash samples were LP-formulated with sewage sludge, poultry manure, CaCO3, and KCl to yield 13 unique mixtures, which were then evaluated in greenhouse pot experiments. Results indicated that normal growth and balanced nutrition of sorghum (Sorghumbicolor L.) and soybean (Glycine max (L.) Merr.) crops were achieved in all mixtures, comparable to a balanced fertilizer reference treatment, and significantly better than the untreated control. Phytotoxic levels of B, NH3, NO2 -, overliming problems, and excessive As levels which were previously encountered from indiscriminate use of these waste materials, were all well controlled by LP-formulated mixtures. Most fly ash quantities in mixtures were limited by either available B (< 4 kg ha-1) or total As (< 2 kg ha-1) restrictions during formulation, while the most alkaline fly ash was limited by its high calcium carbonate equivalence (CCE = 53.9%). These results confirmed that fly ash land application should not be at arbitrary fixed rates, but should be variable, depending on the soil, crop, and particularly the fly ash chemistry. 相似文献
13.
Flameless atomic absorption spectrometry is applied for the determination of Pb in coal, coal ash and fly ash. Lead concentrations in coal and coal ash ranging from respectively 7 to 110 µg g?1 and 120 to 450 µg g?1 are found. A mean concentration of 1520 µg g?1 in fly ash corresponding to a concentration of 117 µg m?3 in the effluent gas suggests the importance of coal combustion as an atmospheric source of Ph. The contribution of coal combustion to the total Pb emissions is conservatively estimated at 6%. 相似文献
14.
Dispersion of saline–sodic soils was rather difficult to leach. Therefore, negative effects of freeze–thaw on soil physical properties should be reduced by inexpensive and practical methods. This study investigates the effect of freeze–thaw cycles (3, 6, and 9) on wet aggregate stability, bulk density, and permeability coefficient in three soils with different electrical conductivity and exchangeable sodium percentage levels (soil I: 5.30 dS m−1, 47.51%; soil II: 42.80 dS m−1, 55.45%; soil III: 36.30 dS m−1, 59.34%) which consist of different proportions of sewage sludge and fly ash by volume (10%, 20%, and 30%). The experiment was conducted under laboratory conditions using disturbed and non-cropped soil samples mixed with sewage sludge and fly ash. Soils mixed with sewage sludge produced higher aggregate stability and permeability coefficients and lower bulk density values as compared to the soils mixed with fly ash. Sewage sludge added with a rate of 30% eliminated the negative effects of freeze–thaw processes on wet aggregate stability. Freeze–thaw processes did not affect the bulk density of the soils II and III, which were mixed with sewage sludge. However, fly ash addition decreased the bulk density of these soils very significantly after nine freeze–thaw cycles. Addition of sewage sludge or fly ash with rates of 20% and 30% significantly increased the permeability coefficients in soil I after nine freeze–thaw cycles. Results indicated that addition of sewage sludge and/or fly ash to saline–sodic soils could be alternative way for reducing negative effects of freezing–thawing on soil wet aggregate stability, bulk density, and permeability coefficient. 相似文献
15.
《Communications in Soil Science and Plant Analysis》2012,43(5-6):503-512
Abstract Fly ash, a by‐product of coal combustion, is often stored in landfills. Stabilization of fly ash deposits can be hindered by phytotoxic levels of B and soluble salts in the ash. Two greenhouse studies were conducted with the objective of improving cover crop establishment on landfills containing fly ash. In one experiment, eight cover crop species were screened for tolerance to fly ash and fly ash‐amended soil, as measured by seedling emergence and early shoot growth. Hairy vetch, red clover, and tall fescue were identified as having the best potential for stabilization of fly ash deposits. Another experiment determined if amending fly ash with a co‐compost, produced from municipal refuse and sewage sludge, would improve the establishment and growth of tall fescue and Korean lespedeza. The co‐compost had no effect on fescue alone, but increased emergence and early growth of lespedesa and a fescue‐lespedeza mixture. 相似文献
17.
The thermophilic bacteria in compost made from coal flyash-amended sewage sludge were isolated and identified using theBiolog system to investigate the effect of coal fly ash on thethermophilic decomposition of sewage sludge during composting. Atotal of 8 species of Bacillus were isolated from thecompost and Bacillus brevis was the dominant speciesduring the entire composting process. The present resultsdemonstrate that the Biolog system is a fast and simple methodfor identifying bacterial species in compost, provided thatoptimum conditions could be achieved for the Bacillusculture. Adding coal fly ash as an amendment did not change thedominant bacteria species during composting, but decreased thepopulation and diversity of thermophilic bacteria species due tothe high alkalinity and salinity. Fewer thermophilic bacteriawere detected in ash-amended sewage sludge compost than insludge compost. There was also reduced metabolic activityobserved in the ash-amended sludge compost from the data ofCO2 evolution and weight loss. Although ash amendmentdemonstrated a negative effect on the population and diversityduring thermophilic phase, it did not cause any significanteffect on compost maturity. 相似文献
18.
商陆(Phytolacca acinosa Roxb.)的锰耐性和超积累 总被引：20，自引：0，他引：20
超积累植物的确证对成功实施重金属污染环境植物修复是必不可少的。通过野外调查和营养液培养试验 ,研究超积累植物商陆 (PhytolaccaacinosaRoxb )的锰富集特性 ,结果表明 ,商陆对生长介质中的Mn具有很强的耐性和累积能力。商陆在锰含量高达 114× 10 3 mgkg-1的尾矿废弃地上依然生长良好 ,叶锰含量最高达 19 3× 10 3 mgkg-1。温室培养条件下 ,当生长介质中Mn浓度为 8 0 0 0mmolL-1时 ,虽然其生物量与对照相比有所降低 ,但植株仍能生长。随着生长介质中Mn浓度的升高 ,商陆叶和茎的Mn含量逐渐增加 ,生物富集系数则逐渐降低 ,但是地上部分锰积累量则先增加后减少。当Mn浓度为 5 0 0 0mmolL-1时 ,商陆地上部分锰积累量达到最大值 2 5 8 2mgplant-1;当Mn浓度为 12 0 0 0mmolL-1时 ,商陆仍能完成整个生命周期 ,叶锰含量达到最大值 36 4× 10 3 mgkg-1,生物富集系数为 5 5。不同锰供应水平下 ,商陆吸收的锰有87%～ 95 %被转移到地上部分。这进一步验证商陆的锰超积累特性 ,为利用超积累植物对大面积污染土壤实施植物修复提供了有力证据 ,对锰污染土壤和水体实施植物修复具有很大的应用前景 相似文献
19.
Thlaspi caerulescens J. and C. Presl is a Zn-hyperaccumulatingplant which has aroused considerable interest with respect to its possible use for phytoremediation of Zn-contaminated soils. In this work, a British population of T. caerulescens, from a soil which was found to have relatively high concentrations of water-extractable Cu (0.22 mg L-1), Pb (0.99 mg L-1) and Zn (6.49 mg L-1), was studied. Its ability to grow and accumulate Zn from hydroponic nutrient solution in the presence of elevated concentrations of Cu and/or Pb was investigated. The chosen concentrations of Cu, Pb and Zn were based on reported water-soluble concentrations of these heavy metals in contaminated soils. When supplied with 32.7 mg L-1 Zn, plants accumulated 19 780 mg kg-1 Zn in their shoot dry matter. This concentration declined by 9.3, 87 and 84% respectively when 5.0 mg L-1 Pb, 1.0 mg L-1 Cu or 2.0 mg L-1 Cu were included in the nutrient solution. Despite the apparent adaptation of this population of T. caerulescens to a Zn/Pb/Cu-contaminated soil, these Cu treatments strongly inhibited growth, but the Pb treatment did not affect growth significantly. 相似文献
20.
《Communications in Soil Science and Plant Analysis》2012,43(7-8):1041-1055
Abstract Rice is a plant that requires high levels of silica (Si). As a silicate (SiO2) source to rice, coal fly ash (hereafter, fly ash), which has an alkaline pH and high available silicate and boron (B) contents, was mixed with phosphor‐gypsum (hereafter, gypsum, 50%, wt wt?1), a by‐product from the production of phosphate fertilizer, to improve the fly ash limitation. Field experiments were carried out to evaluate the effect of the mixture on soil properties and rice (Oryza sativa) productivity in silt loam (SiL) and loamy sand (LS) soils to which 0 (FG 0), 20 (FG 20), 40 (FG 40), and 60 (FG 60) Mg ha?1 were added. The mixture increased the amount of available silicate and exchangeable calcium (Ca) contents in the soils and the uptake of silicate by rice plant. The mixture did not result in accumulation of heavy metals in soil and an excessive uptake of heavy metals by the rice grain. The available boron content in soil increased with the mixture application levels up to 1.42 mg kg?1 following the application of 60 Mg ha?1 but did not show toxicity. The mixture increased significantly rice yield and showed the highest yields following the addition of 30–40 Mg ha?1 in two soils. It is concluded that the fly ash and gypsum mixture could be a good source of inorganic soil amendments to restore the soil nutrient balance in rice paddy soil. 相似文献