scholarly journals Evaluation of the Leachability of Contaminations of Fly Ash and Bottom Ash from the Combustion of Solid Municipal Waste before and after Stabilization Process

2019 ◽  
Vol 11 (19) ◽  
pp. 5384 ◽  
Author(s):  
Monika Czop ◽  
Beata Łaźniewska-Piekarczyk
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Fly Ash ◽  
Bending Strength ◽  
Salt Content ◽  
Bottom Ash ◽  
Municipal Waste ◽  
High Concentration ◽  
Before And After ◽  
Solid Municipal Waste

The aim of this work was to check the possibility of using a concrete matrix to immobilize contaminants from ash (fly and bottom) originating from the combustion of solid municipal waste. This work presents tests of ash from a Polish incineration plant. Nowadays, the management of ash poses a big problem with respect to the high concentration of contaminants that constitutes an environmental nuisance (heavy metals, chlorides, sulfates, etc.). The excessive leaching of contaminants disqualifies ash from being deposited in landfills for hazardous wastes. Bottom ash following the combustion of solid municipal waste mainly contains calcium (23.81%), chlorine (5.44%) and heavy metal (Σ 11.27 g/kg) compounds, while fly ash is characterized by a high content of chlorine (7.22%) and heavy metals (Σ 7.83 g/kg). In the next stage, two concrete mixtures were designed and prepared, containing 30% of ash from combustion of solid municipal waste. The most advantageous physicomechanical properties had concrete mortars that contained 30% of bottom ash: compressive strength—29.48 MPa, bending strength—1678 kN. The performed tests showed that immobilization of dangerous compounds through the C-S-H phase of the concrete significantly decreases the migration of dangerous substance into the environment and minimizes its toxicity. Approximately 97% of the chloride and sulfate salt content was immobilized, and the heavy metal content was immobilized by the C-S-H phase to a degree of 90%. The results obtained provide the option of conveniently managing dangerous wastes with the use of a tight and durable concrete. In many cases, such technology may constitute the best and the cheapest long-term solution in the waste management economy. It may also fill a market gap in this field.

scholarly journals Experimental Study on Solidification of Pb2+ in Fly Ash-Based Geopolymers

2021 ◽  
Vol 13 (22) ◽  
pp. 12621
Author(s):  
Fang Liu ◽  
Ran Tang ◽  
Baomin Wang ◽  
Xiaosa Yuan
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Fly Ash ◽  
Heavy Metal Ions ◽  
Test Results ◽  
Good Resistance ◽  
Domestic Waste ◽  
Before And After ◽  
Better Than ◽  
Solidified Body

Fly ash from the incineration of domestic waste contains heavy metals, which is harmful to the environment. To reduce and prevent their contamination, heavy metal ions need to be sequestered. In this study, the geopolymer prepared by fly ash, a kind of power plant waste, is used to cure the heavy metal Pb2+, and to investigate the effect of different concentrations of Pb2+ on the compressive strength of the solidified body at different ages; the curing effect is judged by the toxic leaching concentration of heavy metals; the resistance of the solidified body to immersion is evaluated by comparing the change in strength before and after leaching; the fly ash-based geopolymer solidified body is compared with the cement solidified body in terms of curing effectiveness; the properties of the geopolymer and its mechanism of curing heavy metals are explored by microscopic tests. The results show that the fly ash-based geopolymer solidified body has good resistance to immersion; the optimum curing concentration of Pb2+ in fly ash-based geopolymers is 2.0%; compared to pure geopolymers, the strength of the solidified body at 28 d decreases by only 13.0%, and the leaching concentration of Pb2+ is 4.73 mg·L−1, which meets the specification requirements; the curing effect of the fly ash-based geopolymer is better than the cement solidified body; the microscopic test results indicate that the curing of Pb2+ by the fly ash-based geopolymer is a combination of both chemical bonding and physical fixation.

Experimental Study on Influence of Fly Ash in Melting Process on Heavy Metal Speciation

2011 ◽  
Vol 347-353 ◽  
pp. 142-146
Author(s):  
Hao Ran Yuan ◽  
Xiao Bo Wang ◽  
Dan Dan Zhao ◽  
Zeng Li Zhao ◽  
Hai Bin Li ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Experimental Study ◽  
Organic Matter ◽  
Fly Ash ◽  
Metal Speciation ◽  
Melting Process ◽  
Heavy Metal Speciation ◽  
Mn Oxide ◽  
Before And After

The influence of melting process on heavy metal speciation was studied. The results show that although there are different changes of heavy metals Cd, Cu, Mn and Zn after melting process, percentage of residue is increasing and others are decreasing. Before melting process, Pb exists mainly in carbonate, Fe-Mn oxide and organic matter bound fractions and in Fe-Mn oxide bound fraction after the process. The percentage distribution of Cr, As, Ba and Ni are not changed obviously before and after melting. In general, the existence forms of all testing heavy metals trend to more stable speciation after melting process.

Characterization of lead-bearing phases in municipal waste combustor fly ash

1996 ◽  
Vol 54 ◽  
pp. 516-517
Author(s):  
L. L. Sutter ◽  
G. R. Dewey ◽  
J. F. Sandell
Keyword(s):  
Fly Ash ◽  
Bottom Ash ◽  
Municipal Waste ◽  
Primary Concern ◽  
Leaching Behavior ◽  
Waste Combustion ◽  
Lead And Cadmium ◽  
Lead Speciation ◽  
Accepted Practice

Municipal waste combustion typically involves both energy recovery as well as volume reduction of municipal solid waste prior to landfilling. However, due to environmental concerns, municipal waste combustion (MWC) has not been a widely accepted practice. A primary concern is the leaching behavior of MWC ash when it is stored in a landfill. The ash consists of a finely divided fly ash fraction (10% by volume) and a coarser bottom ash (90% by volume). Typically, MWC fly ash fails tests used to evaluate leaching behavior due to high amounts of soluble lead and cadmium species. The focus of this study was to identify specific lead bearing phases in MWC fly ash. Detailed information regarding lead speciation is necessary to completely understand the leaching behavior of MWC ash.

ASSESSMENT OF HEAVY METAL CONCENTRATION IN COCONUT WATER

1970 ◽  
pp. 07-10
Author(s):  
MdDidarul Islam, Ashiqur Rahaman, Aboni Afrose
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Heavy Metal Concentration ◽  
Coconut Water ◽  
Toxic Heavy Metals ◽  
High Concentration ◽  
Toxic Heavy Metal ◽  
Low Concentration ◽  
Wet Ashing ◽  
Aas Method

This study was based on determining concentration of essential and toxic heavy metal in coconut water available at a local Hazaribagh area in Dhaka, Bangladesh. All essential minerals, if present in the drinking water at high concentration or very low concentration, it has negative actions. In this study, fifteen samples and eight heavy metals were analyzed by Atomic Absorption Spectroscopy (AAS) method which was followed by wet ashing digestion method. The concentration obtained in mg/l were in the range of 0.3 to 1.5, 7.77 to 21.2, 0 to 0.71, 0 to 0.9, 0 to 0.2, 0.9 to 17.3, 0.1 to 0.9, 0 to 0.9 and 0 to 0.7 for Fe, Ni, Cu, Cd, Cr, Zn, Pb and Se respectively. From this data it was concluded that any toxic heavy metals like Cd, Cr, Pb and Ni exceed their toxicity level and some essential nutrients were in low concentration in those samples. 

Manufacture of Non-Toxic Lava from Recovery of the Incineration Ash by Plasma Fusing Technology

2011 ◽  
Vol 194-196 ◽  
pp. 2365-2375
Author(s):  
Jai Houng Leu ◽  
Li Fong Wu ◽  
Ay Su
Keyword(s):  
Heavy Metals ◽  
Fly Ash ◽  
Dissolution Rate ◽  
Bottom Ash ◽  
Reduction Ratio ◽  
National Standards ◽  
Toxic Heavy Metals ◽  
Mixture Ratio ◽  
Sustainable Operation ◽  
The Stability

This research investigated and explored the overall technical and legal suggestions on mixed ash (bottom ash + fly ash) from the first BOT(built-operation then transfer) incineration plant in south Taoyuan of Taiwan, with the hope of serving as the reference for treating ash from urban refuse incinerator and making sustainable operation management policies in Taiwan. Both bottom ash and fly ash contain high-content harmful metals like lead, chrome, and cadmium, with the lead content exceeding standard value. Plasma fusing technology may effectively settle toxic heavy metals and reduce their dissolution rate. The results show that the increase in percentage of bottom ash could maintain post-fusing strength and produce solidification effect, but this reduced the stability of toxic heavy metals and raised their dissolution rate. Suitable mixture ratio of bottom ash and fly ash was 2:1, volume reduction ratio 0.349, and weight reduction ratio 0.4936. The mixture was fulvous and dense with gloss and adequate strength. The dissolution test of lava products complied with national standards, and they might be used for recycling aggregates and solidifying cement.

Leaching of heavy metals by citric acid from fly ash generated in municipal waste incineration plants

2011 ◽  
Vol 13 (2) ◽  
pp. 118-126 ◽  
Author(s):  
Kai Huang ◽  
Katsutoshi Inoue ◽  
Hiroyuki Harada ◽  
Hidetaka Kawakita ◽  
Keisuke Ohto
Keyword(s):  
Heavy Metals ◽  
Fly Ash ◽  
Citric Acid ◽  
Waste Incineration ◽  
Municipal Waste ◽  
Municipal Waste Incineration

scholarly journals Isolation and Identification of Heavy Metal Tolerant Bacteria from Tannery Effluents

2016 ◽  
Vol 29 (1) ◽  
pp. 23-26
Author(s):  
M Iqbal Hossain ◽  
M Nural Anwar
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Bacillus Coagulans ◽  
Bacillus Firmus ◽  
Chemical Parameters ◽  
High Concentration ◽  
Isolation And Identification ◽  
Tannery Effluents ◽  
Physical And Chemical ◽  
Metal Tolerant Bacteria

The aim and objective of the study was to isolate and characterize heavy metal tolerant microorganisms from tannery effluents. Six effluent samples were collected aseptically and their physical and chemical parameters were determined. A total of 40 bacterial colonies were isolated from these effluent samples. Among them, six bacterial isolates were characterized provisionally as Alcaligenes aquamarinus, Bacillus coagulans, Bacillus firmus, Enterobacter cloacae, Pseudomonas alcaligens and Pseudomonas mendocina based on morphological, cultural and biochemical characteristics. The survibality and tolerance to heavy metals (Cr and Cu) of these isolates were examined. All the isolates were found to grow at high concentration of CuSO4 (95ppm/ml) and varying degrees of chromium (K2Cr2O7). The highest tolerance was shown by Alcaligenes aquamarinus. These heavy metal tolerant organisms could be potential agents for bioremediation of heavy metals polluted environment.Bangladesh J Microbiol, Volume 29, Number 1, June 2012, pp 23-26

Isolation and characterization of heavy metal tolerant Gram-positive bacteria with bioremedial properties from municipal waste rich soil of Kestopur canal (Kolkata), West Bengal, India

Biologia ◽  
2012 ◽  
Vol 67 (5) ◽  
Author(s):  
Kamala Gupta ◽  
Chitrita Chatterjee ◽  
Bhaskar Gupta
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Metal Tolerance ◽  
Environmental Pollutants ◽  
Heavy Metal Tolerance ◽  
Antibiotic Sensitivity ◽  
Bacterial Strains ◽  
High Concentration ◽  
Isolation And Characterization ◽  
Bacillus Weihenstephanensis

AbstractThe present study was conducted to determine the culturable bacterial profile from Kestopur canal (Kolkata, India) and analyze their heavy metal tolerance. In addition to daily sewage including solid and soluble wastes, a considerable load of toxic metals are released into this water body from industries, tanneries and agriculture, household as well as health sectors. Screening out microbes from such an environment was done keeping in mind their multifunctional application especially for bioremediation. Heavy metals are major environmental pollutants when present in high concentration in soil and show potential toxic effects on growth and development in plants and animals. Some edible herbs growing in the canal vicinity, and consumed by people, were found to harbour these heavy metals at sub-toxic levels. The bioconcentration factor of these plants being <1 indicates that they probably only absorb but not accumulate heavy metals. All the thirteen Grampositive bacteria isolated from these plants rhizosphere were found to tolerate high concentration of heavy metals like Co, Ni, Pb, Cr, Fe. Phylogenetic analysis of their 16S rDNA genes revealed that they belonged to one main taxonomic group — the Firmicutes. Seven of them were found to be novel with 92–95% sequence homology with known bacterial strains. Further microbiological analyses show that the alkaliphilic Bacillus weihenstephanensis strain IA1 and Exiguobacterium aestuarii strain CE1, with selective antibiotic sensitivity along with high Ni2+ and Cr6+ removal capabilities, respectively, can be prospective candidates for bioremediation.

scholarly journals The rainfall effect onto solidification and stabilization of heavy metal-polluted sediments

2020 ◽  
Vol 7 (7) ◽  
pp. 192234
Author(s):  
Yan Sun ◽  
Daofang Zhang ◽  
Feipeng Li ◽  
Hong Tao ◽  
Moting Li ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Diffusion Coefficient ◽  
Simulated Acid Rain ◽  
Curing Process ◽  
Deterioration Rate ◽  
Before And After ◽  
Calculated Diffusion Coefficient ◽  
Leaching Procedure

Rainfall makes impacts on the process of solidification/stabilization (S/S) and the long-term safety of solidified matrix. In this study, the effect of rainfall on solidification/stabilization process was investigated by the rainfall test. The unconfined compressive strength (UCS) and toxicity characteristic leaching procedure (TCLP) were adopted to characterize the properties of S/S sediments before and after the rainfall test. The samples cured for 28 days were selected for semi-dynamic leaching tests with a simulated acidic leachant prepared at pH of 2.0, 4.0 and 7.0. The effectiveness of S/S treatment was evaluated by diffusion coefficient ( D e ) and leachability index (LX). The results indicated that UCS decreased at maximum deterioration rate of 34.23% after 7 days of curing, along with the minimum rate of 7.98% after 28 days by rainfall, with greater than 14 days referred. The rainfall had little effect on the leaching characteristics of heavy metals during the curing process. However, the simulated acid rain made significant impacts on the leaching behaviours of the heavy metals in the S/S materials. All the values of cumulative fraction of leached heavy metals were less than 2.0%, exhibition of good stabilization of cement. Furthermore, the calculated diffusion coefficient ( D e ) for Cu was 1.28 × 10 1 cm 2 s –1 , indicating its low mobility of heavy metal ions in S/S sediments. Furthermore, the calculated diffusion coefficients ( D i ) for Cd, Cu and Pb were 7.44 × 10 −11 , 8.18 × 10 −12 and 7.85 × 10 −12 cm 2 s –1 , respectively, indicating their relatively low mobility of heavy metal in S/S sediments.

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