Combustion Melting Characterisation of Solid Fuel Obtained from Sewage Sludge

Solid fuelization technology can increase the heating value of sewage sludge such that it can be utilised as a fossil fuel substitutes. Reducing landfilling of bottom and fly ash resulting from heavy metals contained in sewage sludge is challenging. Hence, combustion melting technology (CMT), which can discharge bottom ash in the form of slag, has been proposed herein as an alternative to the conventional incineration technology. However, further research is required to improve the flowability of slag. Applicability of CMT for the stable treatment of heavy metals in the ash generated during the energisation of sewage sludge solid fuel has been reviewed. The change in the degree of fluidity was identified via a laboratory-scale fluidity measurement experiment following changes in melting temperature, mixing ratio of sewage sludge and sawdust, and basicity. The pouring index (PI) of sewage sludge solid fuel (pellet) was maintained at a level of about 60% at a basicity index of 0.8. Based on the results, the slagging rates and volume reduction rates, exhaust gas analysis, and heavy metal elution characteristics under oxygen enrichment were derived from a 2 ton/day combustion melting pilot plant experiment; thereafter, the feasibility of combustion melting of sewage sludge solid fuel was determined.

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Stabilization of Municipal Solid Waste Fly Ash, Obtained by Co-Combustion with Sewage Sludge, Mixed with Bottom Ash Derived by the Same Plant

Applied Sciences ◽

10.3390/app10176075 ◽

2020 ◽

Vol 10 (17) ◽

pp. 6075

Author(s):

Ahmad Assi ◽

Fabjola Bilo ◽

Alessandra Zanoletti ◽

Laura Borgese ◽

Laura Eleonora Depero ◽

...

Keyword(s):

Heavy Metals ◽

Fly Ash ◽

Sewage Sludge ◽

Municipal Solid Waste ◽

Solid Waste ◽

Coal Fly Ash ◽

Bottom Ash ◽

Solid Material ◽

Flue Gas Desulfurization ◽

Stabilization Method

This study presents an innovative stabilization method of fly ash derived from co-combustion of municipal solid waste and sewage sludge. Bottom ash, obtained from the same process, is used as a stabilizing agent. The stabilization method involved the use of two other components—flue gas desulfurization residues and coal fly ash. Leaching tests were performed on stabilized samples, aged in a laboratory at different times. The results reveal the reduction of the concentrations of heavy metals, particularly Zn and Pb about two orders of magnitude lower with respect to fly ash. The immobilization of heavy metals on the solid material mainly depends on three factors—the amount of used ash, the concentrations of Zn and Pb in as-received fly ash and the pH of the solution of the final materials. The inert powder, obtained after the stabilization, is a new eco-material, that is promising to be used as filler in new sustainable composite materials.

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Sewage Sludge Bottom Ash Characteristics and Potential Application in Road Embankment

Sustainability ◽

10.3390/su12010039 ◽

2019 ◽

Vol 12 (1) ◽

pp. 39 ◽

Cited By ~ 1

Author(s):

Katarzyna Zabielska-Adamska

Keyword(s):

Heavy Metals ◽

Sewage Sludge ◽

Bottom Ash ◽

Construction Materials ◽

Municipal Sewage ◽

Municipal Sewage Sludge ◽

Natural Soil ◽

Incineration Plant ◽

Heavy Metal Concentrations ◽

Soil Solutions

The paper focuses on sustainability-related applications in civil engineering by using environmentally friendly, alternative construction materials. The paper presents geotechnical properties of thermally converted, municipal sewage sludge in a grate furnace in an incineration plant. Bottom ash and its mixture with sand have been tested to show that they can be considered as a substitute for natural soil built-in road embankments. The product of sewage sludge combustion and its combination with sand meet all code requirements for material suitable for road embankments. As a result of the 30% reduction of resistance to failure values after waste soaking, which causes relatively low California Bearing Ratio (CBR) values of soaked waste, waste should be built into places isolated from groundwater and precipitation. That is also indicated by the possibility of heavy metals leaching from the waste because such content is much higher than in uncontaminated soils, although leaching does not exceed the limits commonly quoted for natural soil solutions. Tested bottom ash as a product of combustion in a grate furnace is a more preferred material for earthworks than fly ash generated during incineration in a furnace with fluidized bed due to the particle size and heavy metal concentrations.

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Effect of Composted Sewage Sludge on Metals Leaching Behavior in Municipal Solid Waste Incineration Bottom Ash

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.295-298.418 ◽

2013 ◽

Vol 295-298 ◽

pp. 418-421

Author(s):

Hai Xia Zhang ◽

Takayuki Shimaoka

Keyword(s):

Heavy Metals ◽

Organic Matter ◽

Sewage Sludge ◽

Municipal Solid Waste ◽

Solid Waste ◽

Bottom Ash ◽

Waste Incineration ◽

Municipal Solid Waste Incineration ◽

Mswi Bottom Ash ◽

Composted Sewage Sludge

In order to study the effect of organic matter on the heavy metals leachability from municipal solid waste incineration (MSWI) bottom ash. In the project, the composted sewage sludge (CS) rich in organic matter was mixed with MSWI bottom ash in a certain proportion. e exudation test, determination of the leaching liquid pH, dissolved organic carbon and humus concentration, and the concentration of heavy metals. And the combination of CS and BA in organic compounds and metal content, calculate metal leaching rate. According to the experimental results, analysis of dissolved organic matter and humic acid concentrations and Cu and Cr leaching concentration, showed that when CS mixture ratio of 20%, organic matter and humic substances concentration and Cu and Cr leaching concentrations are highly linear correlation.

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Extraction and Purification of Phosphorus from the Ashes of Incinerated Biological Sewage Sludge

Water ◽

10.3390/w13081102 ◽

2021 ◽

Vol 13 (8) ◽

pp. 1102

Author(s):

Marco Baldi ◽

Andrea Martinotti ◽

Sabrina Sorlini ◽

Ioannis A. Katsoyiannis ◽

Alessandro Abbà ◽

...

Keyword(s):

Heavy Metals ◽

Sewage Sludge ◽

Bottom Ash ◽

Chemical Characterization ◽

Current Method ◽

Isoamyl Alcohol ◽

Subsequent Treatment ◽

Ph Variation ◽

Extraction And Purification ◽

Counter Current

Phosphorus depletion represents a significant problem. Ash of incinerated biological sewage sludge (BSS) contains P, but the presence of heavy metals (e.g., Fe and Al) is the main issue. Based on chemical characterization by SEM-EDS, ED-XRF and ICP-OES techniques, the characteristics and P content of bottom ash (BA) and fly ash (FA) of incinerated BSS were very similar. On BA, P extraction carried out in counter- current with an S:L ratio of 1:10 and H2SO4 0.5 M led to better extraction yields than those of a similar test with H2SO4 1 M and an S:L ratio of 1:5 (93% vs. 86%). Comparing yields with H2SO4 0.5 M (S:L ratio of 1:10), the counter-current method gave better results than those of the crossflow method (93% vs. 83.9%), also improving the performance obtained with HCl in crossflow (93% vs. 89.3%). The results suggest that the purification of the acid extract from heavy metals with pH variation was impractical due to metal precipitation as phosphates. Extraction with H2SO4 and subsequent treatment with isoamyl alcohol represented the best option to extract and purify P, leading to 81% extraction yields of P with low amounts of metals.

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Is the biochar produced from sewage sludge a good quality solid fuel?

Archives of Environmental Protection ◽

10.1515/aep-2016-0043 ◽

2016 ◽

Vol 42 (4) ◽

pp. 125-134 ◽

Cited By ~ 19

Author(s):

Jakub Pulka ◽

Dariusz Wiśniewski ◽

Janusz Gołaszewski ◽

Andrzej Białowiec

Keyword(s):

Sewage Sludge ◽

Temperature Profile ◽

Sulfur Content ◽

Residence Time ◽

Solid Fuel ◽

Initial Energy ◽

Lignocellulosic Waste ◽

Fuel Production ◽

Heating Value ◽

Treatment Experiment

Abstract The influence of sewage sludge torrefaction temperature on fuel properties was investigated. Non-lignocellulosic waste thermal treatment experiment was conducted within 1 h residence time, under the following temperatures: 200, 220, 240, 260, 280 and 300°C. Sawdust was used as lignocellulosic reference material. The following parameters of biochar have been measured: moisture, higher heating value, ash content, volatile compounds and sulfur content. Sawdust biochar has been confirmed to be a good quality solid fuel. High ash and sulfur content may be an obstacle for biochar energy reuse. The best temperature profile for sawdust torrefaction and fuel production for 1 h residence time was 220°C. At this temperature the product contained 84% of initial energy while decreased the mass by 25%. The best temperature profile for sewage sludge was 240°C. The energy residue was 91% and the mass residue was 85%. Higher temperatures in both cases caused excessive mass and energy losses.

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Co-Combustion of Municipal Sewage Sludge and Biomass in a Grate Fired Boiler for Phosphorus Recovery in Bottom Ash

Energies ◽

10.3390/en13071708 ◽

2020 ◽

Vol 13 (7) ◽

pp. 1708 ◽

Cited By ~ 2

Author(s):

Andreas Nordin ◽

Anna Strandberg ◽

Sana Elbashir ◽

Lars-Erik Åmand ◽

Nils Skoglund ◽

...

Keyword(s):

Heavy Metals ◽

European Union ◽

Sewage Sludge ◽

Fixed Bed ◽

Bottom Ash ◽

Phosphorus Recovery ◽

Fixed Bed Reactor ◽

Municipal Sewage ◽

Municipal Sewage Sludge ◽

Critical Element

Phosphorus has been identified as a critical element by the European Union and recycling efforts are increasingly common. An important phosphorus-containing waste stream for recycling is municipal sewage sludge (MSS), which is used directly as fertilizer to farmland. However, it contains pollutants such as heavy metals, pharmaceutical residues, polychlorinated bi-phenyls (PCBs) and nano-plastics. The interest in combustion of MSS is continuously growing, as it both reduces the volume as well as destroys the organic materials and could separate certain heavy metals from the produced ashes. This results in ashes with a potential for either direct use as fertilizer or as a suitable feedstock for upgrading processes. The aim of this study was to investigate co-combustion of MSS and biomass to create a phosphorus-rich bottom ash with a low heavy metal content. A laboratory-scale fixed-bed reactor in addition to an 8 MWth grate-boiler was used for the experimental work. The concentration of phosphorus and selected heavy metals in the bottom ashes were compared to European Union regulation on fertilizers, ash application to Swedish forests and Swedish regulations on sewage sludge application to farmland. Element concentrations were determined by ICP-AES complemented by analysis of spatial distribution with SEM-EDS and XRD analysis to determine crystalline compounds. The results show that most of the phosphorus was retained in the bottom ash, corresponding to 9–16 wt.% P2O5, while the concentration of cadmium, mercury, lead and zinc was below the limits of the regulations. However, copper, chromium and nickel concentrations exceeded these standards.

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