Leaching Behaviour of a Glass Produced from a MSWI Bottom Ash

Abstract

This paper is mainly focused on the characterisation of a glass material (GM) obtained from the thermal treatment of a bottom ash (BA) produced at the Municipal Solid Waste (MSW) incineration plant of Valorsul. By melting the BA at 1400°C during 2 hours, and without using any chemical additives, a homogeneous black-coloured glass was obtained. The thermal and mechanical properties of this glass were characterised. The thermal expansion coefficient, measured by dilatometry, was 9-10 x 10-6 per °C and the modulus of rupture, determined by four-point bending test, was 75±6 MPa, which are similar values to those exhibited by commercial soda-lime-silica glasses used in structural applications. The chemical and the ecotoxicological leaching behaviour of the GM were also analysed. The GM was submitted to a leaching procedure composed of 15 sequential extraction cycles. A liquid/solid (L/S) ratio of 2 l/kg was applied in each cycle. The leachates were filtered through a membrane of PTFE (porosity: 0.45 8m). The filtered leachates were characterised for different chemical parameters and for an ecotoxicological indicator (bacterium Vibrio fischeri). The GM was also submitted to a microwave acidic digestion for the assessment of the total metal content. The crude BA was also submitted to the same experimental procedures. The GM showed levels of chemical emission and ecotoxicity for V. fischeri much lower than those determined for the crude BA. Similar characterisation studies will be pursued with the glass-ceramics produced by adequate thermal treatment of the glass, in order to investigate the effect of the crystallization on the final properties.

Wastewater and Landfill Leachate Testing: Acute Toxicity Biotest Results Evaluation

“…c) l(E)c50 based classification for waste (Wilke et al 2008; Pandard, Römbke 2013). d) Tua (acute toxic units) as an initial, background scoring value for indices or scales -for WW (HELCOM LAND 2007) and for waste (Lapa et al 2006). Tua based more sophisticated indices: avTx -average of toxicity index, i.e.…”

“…These values for industrial WW at the point of discharge toxicity to fish eggs were usually 2 (sometimes up to 6), umu-test 1.5-3, algae test 16, Daphnia 2-8, bacteria 4-32 at 10 (or 20) % effect (HELCOM MONAS 2011). e) Tua values based five toxicity classes were proposed for WW and natural waters (TB use of data) evaluation: a) no-acute toxicity (TU < 0.4); b) slight acute toxicity (0.4 < TU < 1.0); c) acute toxicity (1.0 < TU < 10); and, d) high acute toxicity (10 < TU > 100), very high acute toxicity (TU > 100), (Ronco et al 2005); more simple version was used for waste leachates (Lapa et al 2006 (Vindimian 2005). b) Integration of toxicity strength, persistence and specificity in trophic chain -Tp -toxic print is WW (effluent) characteristic; it is calculated by multiplying average toxicity AvTx and coefficient n (real number of tests which indicated (geno) toxic results).…”

“…The same values based scoring systems are used for different origin aquatic samples: 1) pT-values based classification, applied for WWs (Krebs 2005), was used also for sediment materials (porewater, elutriates, extracts, and solid phases); 2) TU based acute toxicity classes initially were proposed for waste dumps and WW; later these were used for aquatic toxicity evaluation (Sauco et al 2013), with microbiotests in many countries for different environmental samples: natural waters (Greeley et al 2011), WWs (Kontana et al 2008;Carbonell et al 2010); soils, sediments, wastes, biotoxins, etc. Alternatively, TU based classes were used in municipal solid waste (MSW) incineration bottom ash toxicity evaluation (Lapa et al 2006;Tsiridis et al 2012); 3) Potential Ecotoxic Effect Probe, PEEP index was used for WET, integrating TB data (TU form), persistence and WW flow rate (Q), was later modified (without Q, etc.) and also applied as Waste-PEEP for LLs ecotoxicity scoring (Férard, Ferrari 2005).…”

Using Vitrification for Sewage Sludge Combustion Ash Disposal

“…Other reports show the possibility of slag and dust vitrification from an electric arc furnace with the addition of kaolin clay [52]. It has been found that the process of melting occurs at a temperature of about 1200ºC, and then after cooling the products were vitrified.…”