Heavy Metals Behavior during Monocombustion and Co-Combustion of Sewage Sludge

Chemical and physical properties of cyclone fly ash from the grate-fired boiler incinerating forest residues at a small municipal district heating plant (6MW)

“…The metal concentrations in the extracts were determined with a Thermo Elemental IRIS Intrepid II XDL inductively coupled plasma optical emission spectrometer (Franklin, USA). Determination of the dissolved organic carbon (DOC) content in the extractant was carried out according to the SFS-EN 1484 European standard [22,23] using a Shimadzu TOC-V CPH analyser (Shimadzu Inc., Japan). Determination of the chloride, fluoride and sulphate concentrations in the extractant were carried out according to the SFS-EN ISO 10304-1 European standard [24] using a Dionex ICS 2000 ion chromatography with conductivity detection (Dionex Corp., USA).…”

Sludge Acts as a Catalyst for Coal during the Co-Combustion Process Investigated by Thermogravimetric Analysis

“…The optimal sludge content, moisture content and secondary air distribution scheme were determined by the analysis of co-combustion characteristics and NO X emissions. Lopes et al [5] have performed some studies on ash partitioning, the formation of gaseous pollutants, and heavy metals behavior in the co-combustion process of sludge and coal. Karlsson et al [6] discovered that co-combustion of sludge in a fluidized bed boiler can reduce high-temperature corrosion.…”

Co-combustion of coal and sewage sludge: Chemical and ecotoxicological properties of ashes

“…The ashes produced during the co-combustion of coal with SS should be carefully studied, since the substitution of coal by SS can produce ashes with high content of heavy metal, as it was demonstrated by several authors [8][9][10]. Miller et al [8] have studied the trace element emissions from the co-combustion of coal and waste secondary fuels in a bench scale fluidized bed combustor.…”

“…Nevertheless, some benefits have been observed in the retention of As, Pb and Se, in the assays where the addition of SS was performed. Lopes et al [10] have studied the combustion of granular dried SS on a fluidized bed pilot system, under monocombustion and co-combustion conditions with coal. The authors found that the mineral matter of SS was essentially retained in the bottom ashes.…”

“…However, most of the metals were retained in the ashes and their emissions in the flue gases were low. In terms of the leachability, Lopes et al [10] have found that the release of organic metals and heavy metals present in the sludge was very low from bed ashes, which were considered as non-ecotoxic materials. Cyclone ashes seemed to be more problematic due to the high pH values and contamination with steel corrosion products.…”