Environmental Engineering Commons^™

Enriched Coal Ash Utilization For Augmenting Production Of Rice Under Acid Lateritic Soil, S. Karmakar, B.N. Mittra, B.C. Ghosh

Coal Combustion and Gasification Products Journal Archive

The use of industrial wastes such as fly ash (FA) or rice husk ash (RHA), along with paper factory sludge (PFS), farmyard manure (FYM), and chemical fertilizers (CF), under integrated nutrient management, was studied in acid lateritic soil on rice. Application of combined fertilization sources increased growth, yield attributes, and yield (up to 92.3 and 9.7% over control and CF, respectively) of wet season rice. The uptake of N, P, K, Ca, Mg, Fe, Mn, Zn, Cu, and Co was increased under combined fertilization sources. The study also indicated that such integrated plant nutrition system improved physico-chemical properties of soil …

Erosive Wear In Pipelines At Pneumatic Conveying Of Fine Silicon-Containing Materials, Viacheslav Y. Putilov, Vijay K. Agarwal, Irina V. Putilova

Coal Combustion and Gasification Products Journal Archive

Erosive wear is a major operational problem in conveying of hard abrasive bulk materials like silica sand, fly ash, coal dust, etc., in pneumatic conveying systems. Erosion results in emergency downtime of pneumatic conveying installations of ash and slag removal and dust-preparation systems at TPPs caused by holes in pipelines. That leads to worsening of technical, economic, and ecological parameters of thermal power plants as a whole. In MPEI, a model of estimating erosion of rectilinear and curvilinear sections of pneumatic conveying pipelines has been developed. To validate the estimating model developed in the MPEI, experimental investigations in the Indian …

Evaluation Of The Variables That Influence Mercury Capture In Solid Sorbents, M. Antonia Lopez-Anton, Patricia Abad-Valle, Mercedes Diaz-Somoano, M. Rosa Martinez-Tarazona

Coal Combustion and Gasification Products Journal Archive

Newly obtained results on mercury retention in fly ashes and activated carbons during coal combustion are compared with previous findings. The influence of different variables on mercury capture, including the composition and nature of the sorbents, the composition of the flue gas and the mercury species in gas phase is investigated. Coal-fired utility boilers are currently the largest single-known source of mercury emissions. According to the USEPA’s Information Collection Request (ICR), on average, only 40% of the mercury entering a coal-fired power plant is captured, while 60% is emitted into the atmosphere. Several solid materials, including activated carbons, are considered …

Mechanical Performance Of Pavement Geomaterials Stabilized With Fly Ash In Field Applications, Lin Li, Tuncer B. Edil, Craig H. Benson

Coal Combustion and Gasification Products Journal Archive

This paper describes an evaluation of the mechanical performance of fly ash stabilized materials. Soft clay soil, asphaltic recycled pavement material (RPM), and road-surface gravel (RSG) were stabilized using Class C and off-specification fly ashes to create working platforms or stabilized base courses for construction of flexible and rigid pavements at six sites in Wisconsin and Minnesota. California bearing ratio (CBR), resilient modulus (Mr) tests, and unconfined compression (qu) tests were conducted on the subgrade soil, RPM, and RSG alone and on mixtures prepared in the field and the laboratory to evaluate improvements in bearing resistance and stiffness. Fly ash …

Manufactured Coal Ash Aggregates For Aqueous Tnt Sorption, Sangchul Hwang, Victor Hernandez

Coal Combustion and Gasification Products Journal Archive

No abstract provided.

Mineralogy And Leaching Characteristics Of Coal Ash From A Major Brazilian Power Plant, Luis F.O. Silva, Colin R. Ward, James C. Hower, Maria Izquierdo, Frans Waanders, Marcos L.S. Oliveira, Zhongsheng Li, Rachel S. Hatch, Xavier Querol

Coal Combustion and Gasification Products Journal Archive

The feed coals, fly ashes and bottom ashes collected from seven different units in a major Brazilian PF power plant have been subjected to comprehensive mineralogical, geochemical, and petrographic studies, to investigate the links between feed coal and ash characteristics. Ashes from two of the units were collected while the coal was being co-fired with oil as part of the boiler start-up procedure, allowing the impact of oil co-firing on ash characteristics also to be evaluated. High proportions of unburnt carbon and high proportions of retained sulphur were found in the fly ashes produced during oil co-firing, probably reflecting less …

Precipitation Of Germanium From Coal Fly Ash Leachates, Fatima Arroyo, Constantino Fernandez-Pereira, Pilar Coca

Coal Combustion and Gasification Products Journal Archive

The valorization of a coal gasification fly ash was studied by leaching the fly ash using different aqueous solutions followed by the subsequent precipitation of the germanium solubilized from the ash. Experimental investigations were focused on the precipitation of a germanium2catechol (CAT) complex with cetyl trimethyl ammonium bromide (CTAB). The influences of pH and amounts of CTAB and CAT on the precipitation yield were investigated. To this aim, a central composite rotatable design and ANOVA Design Expert 7.0.3 Wiley software were employed for experimental design and analysis of the results. Thus, the independent and combined effects of pH, CAT/Ge and …

The Effect Of Drag-Reducing Additives On The Rheological Properties Of Fly Ash-Water Suspensions At Varying Temperature Environment, H.K. Naik, M.K. Mishra, Rao Karanam U.M.

Coal Combustion and Gasification Products Journal Archive

Fly ash transportation and disposal is a major problem in India. Presently fly ash is being transported as lean slurry in pipe lines requiring about 80 to 85% of water which, in turn, consumes more energy input. The objective of the present study is to evaluate the rheological characteristics of fly ash slurry at varying temperatures with and without an additive to facilitate smooth flow in the pipelines. Six fly ash slurry samples were prepared from the fly ash obtained from a thermal power plant situated in the southern part of India. The main constituents of the slurry were fly …

Waste Stabilization/Solidification (S/S) Of Eaf Dust Using Fly Ash-Based Geopolymers. Influence Of Carbonation On The Stabilized Solids, Y. Luna Galiano, C. Fernandez Pereira, J. Vale

Coal Combustion and Gasification Products Journal Archive

The effect of the curing in a carbonated ambient of the solids obtained after the stabilization/solidification (S/S) of metallurgical waste using geopolymerization technology is described in this paper. The electric arc furnace (EAF) dust to stabilize contains hazardous metals such as Pb, Cd, Cr, or Zn. Different geopolymeric agents such as potassium hydroxide, potassium silicate, metakaolin, and blast furnace slag have been used. Mixtures of EAF waste with these geopolymeric materials and class F fly ash as main silica and alumina source have been processed. Samples were submitted to an accelerated carbonation test. Compressive strength tests and different leaching tests …

Variations In Fly Ash Composition With Sampling Location: Case Study From A Portuguese Power Plant, B. Valentim, A. Guedes, D. Flores, C.R. Ward, J.C. Hower

Coal Combustion and Gasification Products Journal Archive

Fly ash (FA) is a heterogeneous and complex material resulting from coal combustion in thermoelectric power plants (TPP). Therefore, different types of coals, worldwide, produce FAs with different compositions. However, the location of the FA sampling system, inside the TPP, is also important to the composition of the FA produced at each location. A case study of FA from a Portuguese TPP, using several coal and FA characterization techniques (particle size analysis, proximate and ultimate analyses, XRF, SEM/ESEM/EDS, Optical microscopy, XRD, inferred chemistry, and AAS), has shown that FA chemical classification, mineralogy and phase-mineral classification, and trace elements (Cr, Cu, …

Zeolite Synthesised From Fused Coal Fly Ash At Low Temperature Using Seawater For Crystallization, Claudia Belviso, Francesco Cavalcante, Antonio Lettino, Saverio Fiore

Coal Combustion and Gasification Products Journal Archive

A sample of coal fly ash from an Italian thermoelectric power plant was used in order to synthesize zeolite by hydrothermal activation after a pre-treatment fusion with NaOH. The experiments involved were performed at different temperatures of crystallization, ranging from 35 up to 60uC, with seawater and distilled water, separately, during hydrothermal process. A comparison between the results obtained from the use of the different kinds of water showed that at low temperature (35–40 uC) the synthesis yield of zeolite X is higher using seawater as crystallizing agent than using distilled water. This implies a possible application for seawater in …

Arsenite Oxidation By Pure Cultures Of Thiomonas Arsenivorans Strain B6 In Bioreactor Systems, Aniruddha Dastidar

University of Kentucky Doctoral Dissertations

The removal of arsenic toxicity from water is accomplished by a preliminary preoxidative step transforming the most toxic form, arsenite (As (III)), to the least toxic form, arsenate (As (V)). The potential of As (III) oxidation to As (V) was initially investigated in batch reactors using the chemoautotrophic Thiomonas arsenivorans strain b6 under varying initial As (III) and cell concentrations and at optimal pH and temperature conditions (pH 6.0 and temperature 30°C). The strain b6 completely oxidized As (III) to As (V) during exponential growth phase for lower levels of As (III) concentrations (≤ 100 mg/L) but continued into stationary …

Optical Properties Of Coal Combustion Byproducts For Particle-Size Analysis By Laser Diffraction, Robert B. Jewell, Robert F. Rathbone

Coal Combustion and Gasification Products Journal Archive

Laser diffraction analysis is commonly used for determining the particle-size distribution (PSD) of fly ash. However, there is currently no standard method for preparing samples and analyzing them. The Mie and Fraunhofer optical models are used to calculate the PSD of fly ash from laser diffraction data. The Mie theory is most applicable for particles smaller than 50 mm, and is therefore the most accurate model for the analysis of fly ash. However, the refractive index (RI) of fly ash is complex and not well known. This study presents the analysis of several supplementary cementitious materials (SCMs) such as coal …

Process Control Of Activated Sludge Treatment, Richard I. Kermode, Robert W. J. Brett, Kenneth A. Debelak, John J. Davis

KWRRI Research Reports

General feed forward controllers, conforming to standard control modes, have been derived for an activated sludge process. The analysis indicated that the appropriate controllers are proportional control with measurement of substrate flow rate, and derivative control with measurement of inlet substrate concentration, and manipulation of the rate of return sludge by both controllers.

The performance of these controllers was tested by computer simulation of five dynamic aerator models with and without sludge storage, and with two settling basin models. In all cases significant reduction of the maximum exit substrate concentration was achieved. Additional improvement resulted from the use of sludge …