Pond Ash Research Articles

PRETREATMENT OF PHOSPHORUS PLANT PROCESS WASTEWATER CONTAINING ELEVATED LEVELS OF PHOSPHITE, HYPOPHOSPHITE, CYANIDE, AND HEAVY METALS

PRETREATMENT OF PHOSPHORUS PLANT PROCESS WASTEWATER CONTAINING ELEVATED LEVELS OF PHOSPHITE, HYPOPHOSPHITE, CYANIDE, AND HEAVY METALSAlternatives have been evaluated for the management of phosphorus plant wastewater stored in large surface impoundments. The wastewater contains total phosphorus and ortho-phosphate-P concentrations of 4000 and 2000 mg/L, respectively, the difference of which is primarily composed of phosphite and hypophosphite. The wastewater also contains significant levels of fluoride and zinc and lower levels...Author(s)Charles B. BottJohn H. KoonJay R. BrummerSourceProceedings of the Water Environment FederationSubjectSession 5 Pretreatment/Pollution PreventionDocument typeConference PaperPublisherWater Environment FederationPrint publication date Jan, 2003ISSN1938-6478SICI1938-6478(20030101)2003:2L.232;1-DOI10.2175/193864703784343857Volume / Issue2003 / 2Content sourceWEF EventFirst / last page(s)232 - 243Copyright2003Word count165

Raccoon (Procyon lotor) as a bioindicator of mercury contamination at the U.S. Department of Energy's Savannah River Site.

Raccoons (n = 95) were collected from the U.S. Department of Energy's Savannah River Site (SRS) and from public hunting areas. Raccoons were collected near a stream drainage system (Steel Creek delta) and a former reactor-cooling reservoir (pond B) that received inputs of mercury-contaminated Savannah River water. Mercury concentrations were determined for hair, liver, kidney, muscle, and spleen tissues. Samples were analyzed using inductively coupled plasma mass spectroscopy (ICP-MS) and cold vapor atomic absorption spectroscopy (CVAAS). Raccoons were also collected from a natural stream floodplain system (Upper Three Runs/Tinker Creek) located upstream of Hg use and storage areas and near coal ash basins. These samples were compared to samples collected from off-site hunting areas near the SRS. Hg concentrations between internal tissues were significantly correlated. Hair did not correlate well with internal tissue and was a weak indicator of raccoon exposure to Hg. Nonetheless, raccoons are potentially good indicators of Hg contamination because tissue concentrations were higher in raccoons from areas with known Hg input than in those from reference areas, and muscle biopsies can be used as biomarkers for contaminant exposure. Muscle Hg concentrations ranged from 0-0.14 ppm from nearby hunting grounds, indicating that people hunting in designated areas near the SRS are at negligible risk for Hg consumption from raccoon meat. Several raccoons collected from the SRS had muscle Hg concentrations at or near the FDA action level for seizing commercial fish due to mercury contamination of 1.0 ppm. Though Hg action levels for wild game have not been proposed, it is clear that some SRS raccoons had Hg levels that warrant concern if these areas would be open to public hunting. Last, 64 raccoons from this study had Hg concentrations that were considered elevated by the U.S. FWS standard (> 1.1 ppm) of ecosystem health for one or two tissues (hair, liver, or kidney), and 17 had high concentrations for most or all tissues.

Utilization of mixed pond ash in integrated steel plant for manufacturing superior quality bricks

Fly ash (FA) poses serious problems to the industries. Integrated steel plants generate huge quantity of FA from their captive power plants and other furnaces. This ash is generally disposed off in the ash ponds along with other sludges and residues of steel making operations. This changes the constitution of FA and makes the brick manufacturing difficult. This paper has attempted to devise the ways for the use of this mixed ash for manufacturing mixed ash clay bricks successfully. The bricks thus made are superior in structural and aesthetic qualities and portents huge saving in the manufacturing costs with better consumer response.

Screening Evaluation of the Ecological Risks to Terrestrial Wildlife Associated with a Coal Ash Disposal Site

Between 1955 and 1989, coal ash was deposited within an impounded watershed on the U.S. Department of Energy's Oak Ridge Reservation in Tennessee, creating the 3.6 ha Filled Coal Ash Pond (FCAP). The site has subsequently become vegetated wildlife habitat. To evaluate risks that metals in ash may pose to wildlife; ash, surface water, small mammal, and vegetation samples were collected and metal residues were determined. Metal concentrations, As and Se in particular, were elevated in ash, surface water, plant foliage, and small mammals relative to reference materials. Estimates of metal exposures were calculated for short-tailed shrews, white-footed mice, white-tailed deer, red fox, and red-tailed hawks. While shrews and mice were assumed to reside exclusively at and receive 100% exposure from the site, exposure experienced by deer, fox, and hawks was assumed to be proportional to the size of the site relative to their home range. Because deer had been observed to consume ash, presumably for its high sodium content, exposure experienced by deer consuming ash to meet sodium requirements was also estimated. Exposure estimates were compared to body-size adjusted toxicity data for each metal. These comparisons suggest that metals at the site may be detrimental to reproduction and survivorship of mice, shrews, and deer consuming ash for sodium; fox and hawks do not appear to be at risk

Screening Evaluation of the Ecological Risks to Terrestrial Wildlife Associated with a Coal Ash Disposal Site

Between 1955 and 1989, coal ash was deposited within an impounded watershed on the U.S. Department of Energy's Oak Ridge Reservation in Tennessee, creating the 3.6 ha Filled Coal Ash Pond (FCAP). The site has subsequently become vegetated wildlife habitat. To evaluate risks that metals in ash may pose to wildlife; ash, surface water, small mammal, and vegetation samples were collected and metal residues were determined. Metal concentrations, As and Se in particular, were elevated in ash, surface water, plant foliage, and small mammals relative to reference materials. Estimates of metal exposures were calculated for short-tailed shrews, white-footed mice, white-tailed deer, red fox, and red-tailed hawks. While shrews and mice were assumed to reside exclusively at and receive 100% exposure from the site, exposure experienced by deer, fox, and hawks was assumed to be proportional to the size of the site relative to their home range. Because deer had been observed to consume ash, presumably for its high sodium content, exposure experienced by deer consuming ash to meet sodium requirements was also estimated. Exposure estimates were compared to body-size adjusted toxicity data for each metal. These comparisons suggest that metals at the site may be detrimental to reproduction and survivorship of mice, shrews, and deer consuming ash for sodium; fox and hawks do not appear to be at risk

Physical–Chemical Treatment of Groundwater Contaminated by Leachate from Surface Disposal of Uranium Tailings

Leaching of trace elements including heavy metals, nonmetals, and radionuclides from surface impoundments of tailings generated during uranium mining and milling often leads to groundwater contamination. This paper reports results from coagulation and membrane filtration experiments designed to evaluate the capabilities of these processes to remove molybdenum, selenium, uranium, radium, thorium, and other mono- and divalent ions from contaminated groundwater in a shallow unconfined aquifer influenced by uranium tailings. A 10 mg Fe3+/L dose at pH 4 and 10 was found to be very effective for removing radium and thorium that were associated with particles in the raw water. Molybdenum and uranium removals by coagulation are consistent with surface complexation and electrostatic interactions between major coagulant and contaminant complexes in solution. Poor selenium removal suggests that selenate [Se(VI)] was the dominant species in the surficial groundwater. Permeation coefficients (intrinsic transport parameters) for dissolved ions and complexes across three new generation thin-film composite nanofiltration and reverse osmosis membranes evaluated obeyed Gaussian distributions with ionic charge having a mean value of zero. Thus, dissolved solute rejection from brackish multicomponent solutions appears to be only a function of the magnitude of ionic charge and not its sign (positive or negative). Solute permeation coefficients decreased in a power-law fashion with increasing product of molecular weight and absolute ion charge suggesting that both properties determine their removal by nanofiltration and reverse osmosis membranes. Because nanofiltration and reverse osmosis were found to be highly effective for removing a variety of ionic solutes they can be employed in pump and treat operations for groundwater purification prior to reinjection.

Effect of Ash Pond Soil and Amendments on the Growth and Arbuscular Mycorrhizal Colonization of Allium cepa and Germination of Arachis hypogaea, Lycopersicon esculentum, and Vigna mungo Seeds

The effect of fly ash pond soil on the growth and yield of onion (Allium cepa var. microaggregatum) plants grown in pots was investigated. The fly ash pond soil was amended with combinations of red soil and press mud, a waste product from sugar mills. Water-holding capacity of ash pond soil amended with press mud increased; however, addition of press mud delayed onion bulb development. Onion bulb germination took place rapidly in ash pond soil; however, subsequent bulb development declined. The addition of red soil and press mud increased the growth and yield of onion plants. In all the soils and amendments, onion plant roots were colonized by native arbuscular mycorrhizal species. Both vesicles and arbuscules were present in the roots. Colonization was low in ash pond soil but increased with the addition of red soil.Effect of fly ash pond soil on germination of groundnut (Arachis hypogaea), tomato (Lycopersicon esculentum), and black gram (Vigna mungo) seeds was evaluated and compared with red soil in the laboratory. Ash pond soil increased the germination of tomato seeds but did not affect the germination of groundnut and black gram seeds.

Environmental fluxes of arsenic from lignite mining and power generation in northern Thailand

This study evaluated arsenic environmental fluxes in the Mae Moh lignite basin and Mae Moh lignite-burning power plant complex, Mae Moh valley, north Thailand. The excavated lignite, fly ash, stream sediment and surface water surveys were carried out to determine the arsenic distribution in the mining area. Arsenic-rich overburden waste and fly ash piles are scattered throughout the lignite mining area and these have increased the load of arsenic-rich sediment in the nearby streams. A geochemical and hydrogeochemical sampling of the streams that drained into Mae Moh reservoir was completed. The main objective was to study the receiving stream water quality below the area of mining and power plant waste disposal. Arsenic concentration was highest in residual part of the stream sediments. The highest arsenic concentrations were 515 mg/kg in borehole lignite, 312 mg/kg in fly ash, 5,213 mg/kg in reservoir bottom sediment, 325 µg/l in mine sump water, and 8 µg/l in Mae Moh reservoir water. Monitoring of arsenic concentrations around the mining and power plant area, for 1 year, showed the increase of this element around the high fly ash pond and main drain area.

Delineation of groundwater contamination around an ash pond: Geochemical and GIS approach

The study has investigated the levels of metal contamination in groundwater due to particulate matter fallout and leaching from ash pond and assigned contamination indices for the adjacent localities around an ash disposal site with application of geographic information systems (GIS). Fe, Ba, Cu, Mn, S, Pb, V, and Zn were found to be the major contaminants in groundwater. Enrichment factors (EF) of these elements with respect to the United States Environmental Protection Agency (USEPA) maximum contaminant levels show high values for Mn, Fe, and Pb in groundwater. The zone of attenuation for Ba, Fe, Cu, Mn, S, and Zn in groundwater is about 600–900 m from the ash pond, while Pb did not show any significant attenuation even at a distance of 1200 m. Tube wells around Rankasingha and Kukurhanga villages are most contaminated whereas open wells of Lachhmanpur, Kaniapada, and Kurudul villages showed higher degrees of contamination.

Leachability of elements from sub-bituminous coal fly ash from India

Environmental concerns regarding the potential contamination of soil, surface and ground water due to the presence of soluble metal species in the ash pond leachate is of great importance. Serial batch leaching was carried out simulating the rain water condition of the study area to understand the behaviour of elements during leaching. The leachates were analysed for the elements Al, Ca, K, Mg, Na, P, S, Si, As, Ba, Fe, Mn, Mo, Ti, V, Pb, Zn, Co, Cr, Cu, Ni and Cd by inductively coupled plasma optical emission spectrometer (ICP-OES). It was found that Cd, Co, Cr and Ni did not leach from the ash while Cu and Pb concentrations were insignificant in the leachate regardless of liquid to solid (L/S) ratio. Most of the elements showed maximum concentrations at lower L/S ratio and then decreased with increasing L/S. The total cumulative concentrations of As, Mn and Mo were found to be higher than the World Health Organization (WHO) recommended values for drinking water while the concentrations of Fe, Mn and As exceeded the maximum allowable concentrations prescribed by the United States Environmental Protection Agency (USEPA). The pre and post leached ash samples were analysed for morphology, specific surface area and mineralogical changes. Analysis of post-leached fly ash indicated changes in the specific surface area and morphology but no change in mineralogy.

Leaching characteristics of selected Korean fly ashes and its implications for the groundwater composition near the ash disposal mound

Currently only 20% of the fly ash produced in Korea is utilised for industry, and the remainder is disposed as waste in landfill sites. Both anthracite and sub-bituminous coals are burnt in Korea. Fly ash and coal samples were collected from five different coal-fired power stations in Korea and analysed for their chemistry and mineralogy. Batch leaching tests were also carried out to investigate the leaching behaviour of selected fly ashes. The fly ash leachate chemistry was compared with the groundwater taken directly from the monitoring well installed in one of the power stations. The anthracite coals contain illite, pyrophyllite and kaolinite whereas kaolinite is the representative clay mineral for the sub-bituminous coals. Anthracite coals were higher in Si, Al and K than the sub-bituminous coals, reflecting higher mineral matter contents in the anthracite coals. Mullite and quartz are the main mineral phases for two different types of the fly ashes, with some iron oxides. The chemical compositions of the anthracite and sub-bituminous fly ashes are comparable with each other, except for extraordinary high concentrations of Cr for one anthracite fly ash. Most of the trace elements in the ash were enriched in the finer fraction, indicating surface associations. Although, some elements including Na, K, Ca and Cu were released rapidly in the initial stage of leaching, measurable amounts of metals were still detectable in the fly ash leachate treated several times with distilled water. Such leaching behaviour indicates slow and long-term leaching of elements associated with the glass fractions of the ash particle. This was confirmed by leaching of weathered fly ash, which had been disposed of for several years. Comparison of the ash leachate, treated with 0.1N-HCl, fly ash slurry in the ash pond and the groundwater indicate the influence of the ash leachate from the ash disposal mound on the groundwater composition.

Distribution of mycorrhizas in an abandoned fly ash pond and mined sites of Neyveli Lignite Corporation, Tamil Nadu, India

Presence of arbuscular mycorrhizal (AM) species was surveyed in an abandoned lignite fly ash pond, overburden dumps and reclaimed overburden dumps. In ash pond, 15 AM (Acaulospora gerdemannii, Gigaspora decipiens, Gi. gigantea, Gi. margarita, Glomus citricola, Gl. fasciculatum, Gl. formosanum, Gl. fulvum, Gl. maculosum, Gl. magnicaule, Gl. mosseae, Gl. tenebrosum, Sclerocystis pachycaulis, Scutellospora erythropa and Sc. fulgida) were isolated. From overburden and reclaimed overburden dumps, 4 (Gl. fasciculatum, Gl. mosseae, Sclerocystis microcarpus, and Scutellospora verrucosa) and 13 AM fungal species (Acaulospora gerdemannii, Entrophospora colombiana, Gigaspora gigantea, Gi. margarita, Glomus fasciculatum, Gl. macrocarpum, Gl. mosseae, Gl. vesiculiferum, Sclerocystis pachycaulis, S. sinuosa, Scutellospora coralloidea, Sc. erythropa and Sc. persica) were isolated, respectively. In all the sites, Glomus mosseae was the dominant AM fungus. From Acacia auriculiformis plantation in the overburden dumps, fruit bodies of ectomycorrhizal fungus Pisolithus tinctorius were recorded. Soil pH, electrical conductivity, organic carbon and N, P, K content of rhizosphere soils were analyzed to find their influence on mycorrhizal colonization. In einem aufgegebenen Braunkohle-Flugasche-Teich, in Abraumhalden und rekultivierten Abraumhalden wurde das Vorkommen arbuskulärer Mykorrhiza (AM) untersucht. Im Asche-Teich wurden 14 Arten AM isoliert (Acaulospora gerdemannii, Gigaspora decipiens, Gi. gigantea, Gi. margarita, Glomus citricola, Gl. fasciculatum, Gl. formosanum, Gl. fulvum, Gl. maculosum, Gl. magnicaule, Gl. mosseae, Gl. tenebrosum, Sclerocystis pachycaulis, Scutellospora erythropa und Sc. fulgida). Aus den Abraumhalden wurden 4 Arten (Gl. fasciculatum, Gl. mosseae, Sclerocystis microcarpus und Scutellospora verrucosa) und aus den rekultivierten Abraumhalden 13 AM-Pilzarten isoliert (Acaulospora gerdemannii, Entrophospora colombiana, Gigaspora gigantea, Gi. margarita, Glomus fasciculatum, Gl. macrocarpum, Gl. mosseae, Gl. vesiculiferum, Sclerocystis pachycaudalis, S. sinuosa, Scutellospora coralloidea, Sc. erythropa und Sc. persica). An allen Probeorten war Glomus mosseae der dominante AM-Pilz. In den Acacia auriculiformis-Pflanzungen auf den Abraumhalden wurden Fruchtkörper des ektomykorrhizalen Pilzes Pisolithus tinctorius gefunden. Der Boden-pH, die elektrische Leitfähigkeit, der organische Kohlenstoff und die N-, P- und K-Gehalte des Rhizosphären-Bodenswurden analysiert, um ihren Einfluss auf die Besiedlung durch Mykorrhiza zu finden.

Geosynthetic clay liners

Over the past decade, geosynthetic clay liners (GCLs) have gained widespread popularity as a substitute for compacted clay liners in cover systems and composite bottom liners. They are also used as environmental protection barriers in transportation facilities or storage tanks, and as single liners for canals, ponds or surface impoundments. As a result, they are being investigated intensively, especially in regard to their hydraulic and diffusion characteristics, chemical compatibility, mechanical behaviour, durability and gas migration. In this paper, a review of the main findings is presented with the focus on the critical aspects affecting the service life of GCLs. From this work, a general insight is gained on the design implications for systems that incorporate GCLs.

Assessment of Tolerant Sunfish Populations (Lepomis sp.) Inhabiting Selenium-Laden Coal Ash Effluents: 3. Serum Chemistry and Fish Health Indicators

Sunfish were collected from fly ash discharge-receiving streams to assess the possible effects of exposure to elevated selenium. Concentrations of selenium, copper, and arsenic were statistically higher in fish tissue (liver) samples from effluent-exposed fish than in reference fish. Several biomarkers were indicative of metal exposure and effect. Plasma protein levels and cholesterol levels were significantly lower in exposed fish, indicating nutritional stress. Ion levels (i.e., K) increased with exposure to ash pond metals, indicating possible gill damage. Fish from the receiving streams also had increased serum glucose and osmolality indicating possible acute stress due to sampling. Fish health assessments revealed a lower incidence of fin erosion, kidney discoloration, urolithiasis or nephrocalcinosis, liver discoloration, and parasites in exposed fish and a higher incidence of skin, eye, and gill aberrations. Condition factors of exposed fish were correlated with biomarker response and were the same as or lower than those of reference fish, but not related to selenium levels. Although several serum biochemical indicators differed between the ash pond-receiving stream and reference sites, pollutant exposure was apparently not sufficient to cause functional damage to critical organ systems.

Assessment of Tolerant Sunfish Populations (Lepomis sp.) Inhabiting Selenium-Laden Coal Ash Effluents: 2. Tissue Biochemistry Evaluation

Sunfish were collected from a fly ash pond-receiving stream and an Ohio River reference site to assess biochemical responses to coal ash effluent exposure. Selenium levels in sunfish from the receiving stream were higher than toxic thresholds associated with adverse population effects and reproductive impairment. Tissue biochemistry was found to be indicative of metal exposure and effect, but varied widely. Liver glycogen was positively correlated with increased liver metal levels, indicating no adverse effect upon stored carbohydrate levels. Lipid levels decreased with increasing metals, indicating possible nutritional stress. Protein levels increased with increasing metal levels, possibly due to the synthesis of proteins to sequester the metals. ATPase, dUTPase, and alkaline phosphatase activity generally decreased with exposure to ash pond metals, but remained within normal physiological ranges. Fish condition factors and liver somatic indices were correlated with liver lipid levels, dUTPase activity, and gill ATPase and alkaline phosphatase activity. Exposure to coal ash effluents produced biochemical markers of exposure that were associated with fish condition indicators; however, the indices themselves were not significantly affected by effluent exposure.

Sealing pond bottoms with muddy water

Seepage losses from constructed wetlands, wildlife refuges, wastewater lagoons, runoff collection ponds, and other engineered surface impoundments of water or aquatic ecosystems in areas with deep groundwater levels can be minimized with artificial liners (plastic, compacted earth, etc.) or with natural processes like sediment accumulation and microbiological and chemical processes. Sediment accumulation can be increased by deliberately adding soil slurries or muddy (turbid) water. When these are applied to the water surface, settling of the particles to the bottom then creates a graded sediment layer with the coarsest particles on the bottom and the finest particles on top. Column studies in the laboratory showed that, for a given amount of soil added, such a graded layer gives more seepage control than a compacted earth liner. Also, split slurry applications to create a layered lining gave more seepage control than when the same total amount of soil was given in one single slurry application. Subsequent addition of sodium carbonate to the water reduced seepage even more, giving a total seepage reduction in the columns from 1000 to 0.2 cm/day. The study also indicates the importance of avoiding turbid inflows into infiltration basins for groundwater recharge, as well as soil erosion within the basins themselves, if infiltration rates need to be maximized.

Characterization of an alkali activated lagoon ash and its application for heavy metal retention

The wet disposal of ash, from the coal-fired thermal power plants, involves its mixing with water and its impoundment in the ash ponds or lagoons. This causes the interaction of ash and the alkalies present in it with water over a period and the formation of ash zeolites (i.e. zeolitization of the ash) takes place. In order to simulate such ash–water interactions, alkali activation of a typical lagoon ash, from India, has been conducted. Investigations have been conducted to identify the effect of zeolitization of the ash on its physical, chemical and mineralogical characteristics. Such studies are essential to explore the possibility of application of the lagoon ash, and the zeolitized ash, for various environmental applications, viz. retention and removal of heavy metals from the industrial sludge.

Physical, chemical, mineralogical, and thermal properties of cenospheres from an ash lagoon

A small percentage of the particles, present in the pulverized coal ash, consists of thin-walled hollow spheres or cenospheres. Their quantity depends on the carbon and iron contents present in the ash. The apparent density of these cenospheres is less than that of water and as such, they float on the ash slurry when it is impounded in the ash ponds or lagoons. Cenospheres are being used in different industrial applications, mainly due to their low density, high strength, and good thermal properties. However, it is important and mandatory to study and characterize these ash particles for a better and effective usage. As such, an effort has been made in this paper to study physico–chemico–mineralogical and thermal properties of the cenospheres obtained from an ash lagoon.

Angle of Internal Friction for Pond Ashes

Abstract Thermal power stations use pulverized coal as fuel, producing enormous quantities of ash as a waste product of combustion. Nearly 800 million metric tons of ash is produced each year all over the world. In India, presently 97 million metric tons of ash is produced annually by power stations. The problem of ash disposal is a difficult one due to the limited availability of vacant space around the power plants. In view of the large quantities of ash, its bulk utilization is essential, which is possible only through geotechnical applications such as embankments, back-fill material, subbase material, and the like. For the above applications, one of the important engineering properties is the angle of internal friction, which is determined either by box shear or triaxial shear tests. This paper examines the angle of repose of pond ashes and its relation with the angle of internal friction, using direct shear tests. Determination of the angle of repose is an easy and quick procedure for cohesionless materials. The angles of repose of sand and of quarry dust also are examined for comparison purposes. A relationship between angle of internal friction for materials in the loose, dry condition and the angle of repose is established. Further, a simpler method of measurement of the angle of repose is proposed.

Effect of Zeolitization on Compaction, Consolidation, and Permeation Characteristics of a Lagoon Ash

Abstract A common method of disposing of ash generated from coal-fired thermal power plants is wet disposal, where the ash is mixed with water to make a slurry and is disposed of in ash ponds or lagoons. Such a disposal system allows for ash-water interaction, and alkalis present in the ash react with water, leading to the formation of ash zeolites. Formation of zeolites alters the overall properties of the ash. Controlled laboratory experiments have been conducted on a lagoon ash to determine the effects of zeolitization on its physico-chemico-mineralogical properties. Further investigations have been carried out to demonstrate the effect of zeolitization of the ash on its geotechnical properties such as its compaction, consolidation, and permeation characteristics. Such a study is required for bulk utilization of the ash (as a fill material) where compaction, consolidation, and permeation properties are most important.