Evolution of Heavy Metals Leachability and Speciation in Residues of Sewage Sludge Treated by Microwave assisted Pyrolysis

2012 ◽  
Vol 178-181 ◽  
pp. 833-837 ◽  
Author(s):  
Lin Fang ◽  
Na Na Yuan ◽  
Yi Guang Wu ◽  
Xu Xin Zhao ◽  
Hong Yuan Sun
Keyword(s):  
Heavy Metals ◽  
Sewage Sludge ◽  
Sequential Extraction ◽  
Extraction Procedure ◽  
Stable Phase ◽  
Toxicity Characteristic Leaching Procedure ◽  
Microwave Assisted ◽  
Novel Approach ◽  
Conventional Pyrolysis ◽  
Leaching Procedure

In this study the sewage sludge are treated by microwave assisted pyrolysis (MAP) with different microwave receptors, and then, the immobilization of heavy metals in the residues are evaluated through the toxicity characteristic leaching procedure (TCLP) and sequential extraction procedure. The volatilization of Cd, Pb and Zn could be decreased by MAPs more efficiently than the conventional pyrolysis (CP). The average leaching percentages of Cu, Zn and Pb in residues produced by MAPs are decreased 90%, 88% and 81% more than the CP process respectively, and no leaching Cd is detected. Moreover, more than 67% of Cu, Pb, Zn and 55% of Cd in residues of MAP speciated into stable phase, which is higher than the metals in the residues of CP. The effect of heavy metals stabilized in residues of MAP was determined in the order as Cd > Cu > Pb > Zn. The results suggest the immobilization of heavy metals in the residues are enhanced in the process of MAP. This novel approach should be of significance in immobilizing heavy metals in residues of sewage sludge.

Speciation of heavy metals in untreated sewage sludge by using microwave assisted sequential extraction procedure

2009 ◽  
Vol 163 (2-3) ◽  
pp. 1157-1164 ◽  
Author(s):  
Muhammad K. Jamali ◽  
Tasneem G. Kazi ◽  
Muhammad B. Arain ◽  
Hassan I. Afridi ◽  
Nusrat Jalbani ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Sewage Sludge ◽  
Sequential Extraction ◽  
Extraction Procedure ◽  
Sequential Extraction Procedure ◽  
Microwave Assisted ◽  
Untreated Sewage

Time-saving application for sequential extraction of heavy metals by optimized BCR method and lixiviation from untreated sewage sludge

2009 ◽  
Vol 57 (2) ◽  
pp. 215-230 ◽  
Author(s):  
M. Jamali ◽  
T. Kazi ◽  
M. Arain ◽  
H. Afridi ◽  
J. Baig ◽  
...  
Keyword(s):  
Waste Water ◽  
Heavy Metals ◽  
Reference Material ◽  
Sewage Sludge ◽  
Sequential Extraction ◽  
Certified Reference Material ◽  
Extraction Procedure ◽  
Domestic Waste ◽  
Bcr Sequential Extraction ◽  
Optimum Recovery

This article describes an improvement in the modified BCR three-step sequential extraction procedure employed for heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) in untreated domestic waste-water sewage sludge collected from different cities in Pakistan.The BCR sequential extraction protocol requires 16 h for each step, whereas in the present work optimum recoveries of all heavy metals were attained in 10 h/step. The validity of the proposed BCR sequential extraction procedure was checked using certified reference material (BCR 483). Various parameters such as time interval (2–16 h) and sample mass (0.2–1.0 g) were studied to achieve optimum recovery of the heavy metals studied. The extracted analytes were determined by atomic absorption spectrometry. The optimum recovery of heavy metals from the certified reference material and from experimental samples was achieved at a sample mass of 0.4 g, while the time required for extraction on a mechanical shaker at 30 rpm was found to be 26–32 h. The sequence of easily available (acid-exchangeable) heavy metals was determined as Cd<Zn<Ni<Cr<Pb<Cu. With the exception of Cd the dominant fractions of the heavy metals were associated with organic matter, while 31.0 and 47.8% of Cd was present in acid-soluble and reducible forms, respectively. A lixiviation test (DIN 38414-S4) was used to evaluate the leaching of heavy metals from the domestic waste-water sewage sludge used for agricultural purposes.

Fractionation of Heavy Metals in Sewage Sludges

1985 ◽  
Vol 17 (4-5) ◽  
pp. 587-598 ◽  
Author(s):  
R. J. Oake ◽  
C. S. Booker ◽  
R. D. Davis
Keyword(s):  
Heavy Metals ◽  
Sewage Sludge ◽  
Sequential Extraction ◽  
Extraction Procedure ◽  
Sequential Extraction Procedure ◽  
Organic Fraction ◽  
Sewage Sludges ◽  
Exchangeable Fraction ◽  
Complete Extraction

Metals (Cd, Cr, Cu, Ni, Pb and Zn) have been fractionated in representative sewage sludges (primary, secondary, digested) by a sequential extraction procedure using KNO3 1M (removes the ‘exchangeable' fraction), KF 0.5M (‘sorbed'), Na4P2O7 0.1M (‘organic'), Na2EDTA 0.1M (‘carbonate') and HNO3 6M (‘sulphide'). Major differences according to sludge type were not seen. Cd occurred mainly in the ‘carbonate' fraction and 38–62% of Cr was in the ‘organic' fraction. 43–70% Cu was in the sulphide fraction whilst &gt;40% of Ni was extracted in the ‘exchangeable/sorbed' fractions. Pb was found predominantly in the ‘organic' and ‘carbonate' fractions and Zn in the ‘organic' fraction. The complete extraction procedure removed 54–100% of the total metals content of the sludges. Changes in fractionation caused by drying, storage and time of extraction are reported. The results form the first part of a detailed investigation into the chemistry of metals in sewage sludge.

Fraction Distribution Changes of Heavy Metals in Co-Pyrolysis of Sewage Sludge and Corn Straw

2011 ◽  
Vol 236-238 ◽  
pp. 187-191 ◽  
Author(s):  
Qiu Rong Zhang ◽  
Shuang Quan Zhang ◽  
Ting Ting Pan
Keyword(s):  
Heavy Metals ◽  
Sewage Sludge ◽  
Sequential Extraction ◽  
Pyrolysis Temperature ◽  
Extraction Procedure ◽  
Sequential Extraction Procedure ◽  
Residual Fraction ◽  
Corn Straw ◽  
Icp Ms ◽  
Fraction Distribution

Maiz’s short sequential extraction procedure was used to extract the heavy metals in the carbon residues made from sewage sludge by co-pyrolysis with corn straw. The content of heavy metals in the residues was determined by ICP-MS to study the fraction distribution changes of heavy metals. It is concluded that the content of mobile and mobilization heavy metals exsisted in the residue decrease and the content of residual heavy metals increase due to the co-pyrolysis. The co-pyrolysis temperature has great effect on the fraction distribution changes of heavy metals. The content of residual fraction for Cr, Ni, Pb is up to the top at 700°C and for Cd、Cu、Zn is at 500°C. The carbon residues are unhazardous and safe.

scholarly journals Migration and transformation of heavy metals during the microwave-assisted thermal hydrolysis of sewage sludge

2021 ◽  
Author(s):  
Chunsheng Qiu ◽  
Jinxin Zheng ◽  
Chenchen Wang ◽  
Bingbing Wang ◽  
Nannan Liu ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Sewage Sludge ◽  
Ecological Risk ◽  
Risk Index ◽  
Oxygen Demand ◽  
Microwave Treatment ◽  
Potential Ecological Risk ◽  
Ammonium Nitrogen ◽  
Thermal Hydrolysis ◽  
Microwave Assisted

Abstract The migration, transformation and ecological risk of heavy metals (Cr, As, Ni, Cu, Zn, Cd and Pb) in the sewage sludge during the microwave-assisted thermal hydrolysis process were investigated under different temperatures (80 °C, 100 °C, 120 °C, 140 °C, and 160 °C). The potential relationship between the bio-availability of heavy metals and the variables of microwave treatment, including pH, ammonium-nitrogen, soluble chemical oxygen demand, pH, soluble protein, soluble polysaccharide and volatile solid, was also explored. The results showed that the migration of heavy metals between solid-liquid phase mainly depended on the temperature. The percentage of all heavy metals (except Cu) in mobile (acid-soluble/exchangeable and reducible) forms decreased after microwave-assisted thermal hydrolysis treatment. The solubilization of compounds with C = O and O-H accompanied with the generation of organic and inorganic metal halides were also observed in the treated sludge through fourier transform infrared spectroscopy analysis. NH4+-N showed the highest negative correlation to the bio-availability of most heavy metals (except Cu and Cr) with coefficients (absolute value) over 0.87 (P &lt; 0.05). VS showed a positive correlation to the bio-availability of most heavy metals (except Cu). The total potential ecological risk index (RI) decreased by 46.65% after microwave treatment at 160 °C.

scholarly journals Optimization of a microwave-assisted extraction procedure for the determination of selected alkyl, aryl, and halogenated phenols in sewage sludge and biosolids

2016 ◽  
Vol 51 (4) ◽  
pp. 344-356 ◽  
Author(s):  
Hing-Biu Lee ◽  
M. Lewina Svoboda ◽  
Thomas E. Peart ◽  
Shirley Anne Smyth
Keyword(s):  
Sewage Sludge ◽  
Extraction Procedure ◽  
Negative Ion ◽  
Gas Chromatography Mass Spectrometry ◽  
Microwave Assisted Extraction ◽  
Alkyl Aryl ◽  
Microwave Assisted ◽  
Assisted Extraction ◽  
Halogenated Phenols

A microwave-assisted extraction method for the determination of 15 alkyl, aryl, and halogenated phenols in sewage sludge and biosolids samples was developed and optimized. The effects of solvent, temperature, time, moisture content, acid, and number of extractions on the recovery of phenols were evaluated. Results indicated that extraction solvent had the greatest impact on the recovery of all phenols while pH had the largest effect on recovery of hexachlorophene and pentachlorophenol. Wet sludge samples were extracted with acetone-hexane mixture in the presence of glacial acetic acid. The extract was evaporated, acetylated by acetic anhydride and cleaned up by silica gel. For dry sludge samples, an optional procedure for the simultaneous extraction and acetylation of phenols was also proposed. Triclosan (TCS) and the alkyl and aryl phenols in sludge extracts were analyzed by gas chromatography-mass spectrometry (GC-MS) in electron-impact mode while polyhalogenated phenols were analyzed by GC-MS in negative ion chemical ionization mode. Method detection limits were ca. 200 ng/g for nonylphenol, &lt;25 ng/g for TCS and other alkyl and aryl phenols, and &lt;5 ng/g for other halogenated phenols. This method has been applied to the determination of phenolic compounds in over 150 sludge and biosolids samples since 2009.

Influence of Decreasing Supplementation to Transformation of Chemical Forms of Ni, Zn and Cu During Composting of Sewage Sludge

2021 ◽  
Vol 23 ◽  
pp. 580-593
Author(s):  
Robert Sidełko
Keyword(s):  
Heavy Metals ◽  
Sewage Sludge ◽  
Organic Carbon ◽  
Ion Exchange ◽  
Beneficial Effect ◽  
Sequential Extraction ◽  
Nitrogen Concentration ◽  
Chemical Forms ◽  
N Value ◽  
Mobile Forms

This paper pertains to the influence of decreasing supplementation to transformation of chemical forms of Ni. Zn and Cu during composting of sewage sludge. A universally used supplementing material constituting a rich source of organic carbon is straw. Addition of straw to sewage sludge is aimed at increasing C/N proportion up to at least 15 due to the risk of formation of toxic forms of nitrogen, concentration of which in sewage sludge is exceptionally high. We have presented in this paper the results of speciation research of three elements applying Tessier’s sequential extraction. It’s been proven that decreasing of straw share in the composted mixture with sewage sludge down to the level of C/N value below the admissible value, has a beneficial effect on the allocation of tested heavy metals towards the forms that are permanently bound in compost matrix. A systematic increase of organic (IV) and residual (V) fractions share and decrease of mobile forms of heavy metals content in bioavailable fractions i.e. ion-exchange (I) and carbonate (II) has been ascertained.

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