城市垃圾焚烧飞灰制复合阿利尼特水泥的试验研究

以城市垃圾焚烧(MSWI)飞灰为主要原料,在实验室成功烧制了阿利尼特水泥熟料,研究了研制的阿利尼特水泥熟料与石膏及混合材的适应性.结果表明,阿利尼特水泥宜添加石膏作为激发剂,适宜掺量为5％;阿利尼特矿物水化很快,可能是其早期强度的主要来源,具有开发为一种快硬水泥的潜能.MSWI飞灰和矿渣粉适宜用作阿利尼特水泥的混合材,试样AB3(阿利尼特水泥熟料80％+石膏5％+MSWI飞灰15％)和试样AD3(阿利尼特水泥熟料80％+石膏5％+矿渣粉15％)为较适宜比例.     

城市生活垃圾焚烧底灰的水热固化研究

利用水热技术对城市生活垃圾底灰进行资源化利用研究,将其固化为一种强度高、重金属溶出少的建筑材料.主要研究了添加消石灰固化生活垃圾底灰的硬化机理,并且为了100%利用垃圾焚烧灰,也研究了添加垃圾飞灰固化底灰的方法.同时还进行了重金属浸出试验,测试固化体中重金属溶出量.研究结果表明,托勃莫来石晶体的生成是影响固化体强度的主要原因,而且托勃莫来石的生成量越多,样品的强度越高.飞灰也可以作为一种固化添加剂对底灰进行水热固化,且添加飞灰的硬化机理和消石灰相同.经过水热固化,固化体的重金属溶出量可大大降低.水热技术有望成为一种城市生活垃圾底灰资源化利用的有效方法.     

Interactions between municipal solid waste incinerator bottom ash and bacteria (Pseudomonas aeruginosa)

Municipal solid waste incinerator bottom ash (MSWI BA) can be used in road construction where it can become exposed to microbial attack, as it can be used as a source of oligoelements by bacteria. The extent of microbial colonization of the bottom ash and the intensity of microbial processes can impact the rate of leaching of potentially toxic elements. As a consequence, our objective was to highlight the mutual interactions between MSWI bottom ash and Pseudomonas aeruginosa, a common bacteria found in the environment. Experiments were carried out for 133 days at 25 degrees C using a modified soxhlet's device and a culture medium, in a closed, unstirred system with weekly renewal of the aqueous phase. The solid products of the experiments were studied using a laser confocal microscopy, which showed that biofilms formed on mineral surfaces, possibly protecting them from leaching. Our results show that the total mass loss after 133 days is systematically higher in abiotic medium than in the biotic one in proportions going from 31 to 53% depending on element. Ca and Sr show that rates in biotic medium was approximately 19% slower than in abiotic medium during the first few weeks. However, in the longer term, both rates decreased to reach similar end values after 15 weeks. By taking into account the quantities of each tracer trapped in the layers we calculate an absolute alteration rate of MSWI BA in the biotic medium (531 microg m(-2) d(-1)) and in the abiotic one (756 microg m(-2) d(-1)).     

Characteristics of municipal solid wastes incineration (MSWI) fly ash–cement matrices and effect of mineral admixtures on composite system

An experimental work was carried out to investigate the feasibility of application of MSWI fly ash as an auxiliary cementitious material. The water demand for normal consistency, setting time, volume stability, flexural and compressive strength of MSWI fly ash–cement compound matrices were tested. And, the composite effect and the influence of mechanical properties and heavy metals solidification are studied by mixing MSWI fly ash–cement matrices with common mineral admixtures. The results show that the MSWI fly ash has some cementitious activity, but the reactivity is relatively lower and its addition to cement may lead to retardation of cement hydration. After incorporation of common mineral admixtures, the strength of solidified body was enhanced, and the effect of the heavy metals-immobilizing may be reinforced.     

Evaluation of carbonated incineration bottom ash using exhaust gas and CO2 discharged from waste incineration facilities as ground material

This study focused on a carbonation treatment that immobilizes trace elements such as lead (Pb) in incineration bottom ash (IBA) using the exhaust gas and the refined carbon dioxide generated (CO₂) recovered at the Japan's first incineration facility, which recovers CO₂ in the gaseous form. This study describes (1) the bearing capacity of IBA from the municipal solid waste (MSW) obtained through the California bearing ratio (CBR) test to investigate the possibility of using IBA as a base course material, (2) mechanical characteristics of IBA using the cone index test, to investigate the possibility of using as an embankment material, and (3) leaching properties of IBA from MSW obtained through a single batch leaching test and the long-term outdoor exposure of the leaching test to evaluate the effect of carbonation treatments. Results reveal that there was no effect of trace components not included in the separated and recovered CO₂, and that the effect of carbonation could be obtained even if the exhaust gas was used directly. The carbonated IBA can be applied as a sub-base course material based on its mechanical properties, regardless of the carbonation conditions. In addition, carbonated IBA can be used as an embankment material owing to its sufficient cone index value. Regarding the heavy metal and metalloid leaching behavior, it was revealed that all the IBA samples satisfied the soil environmental standards set by the Ministry of the Environment, Japan, except for Cr (VI). The long-term leaching characteristics of carbonated IBA showed that Pb could be immobilized over a long period.     

Evaluation of the genotoxic, mutagenic and oxidant stress potentials of municipal solid waste incinerator bottom ash leachates

Triplicate aqueous leachates of a municipal solid waste incineration bottom ash (MSWIBA) were produced according to a European standardised method. Leachates analysis showed relatively low concentrations (less than 1 mg.l(-1)) for four metals (iron, cadmium, lead and copper). No mutagenic activity was revealed after performing the Salmonella/microsome assay with and without microsomal activation. With the Vicia root tip micronucleus assay, a significant increase in micronucleated cells was observed between 3.4% and 100% leachate concentration. Significant and elevated antioxidant stress enzyme activities, e.g., superoxide dismutase (SOD), catalase (CAT), peroxidase (PER) and glutathione reductase (GR), were detected in Vicia root tissues even at the lowest tested leachate concentration (i.e., 0.3%), whereas this was not always the case in leaf tissues, which showed tissue specificity for the tested enzymes. At the lowest concentration (i.e., 0.3%), a higher increase was observed (respectively 197% and 45% compared to the control) for root glutathione reductase and peroxidase activities over those of other enzymes (superoxide dismutase and catalase). Our results suggest that MSWIBA aqueous leachates need to be formally tested with genotoxic sensitive tests before recycling and support the hypothesis that plant genotoxicity is related to the cellular production of reactive oxygen species (ROS).     

城市垃圾焚烧底渣再生微粉强度特性的实验研究

为实现城市垃圾焚烧底渣的高效再生利用,进行了底渣及其再生微粉的物理、化学性质实验,采用不同比例底渣再生微粉替代水泥进行胶砂强度实验。结果表明：垃圾焚烧底渣再生微粉相比水泥材质更轻、颗粒更小、更均匀;再生微粉中以氧化物形式存在的Si、Al和Ca约占底渣总质量的70%,与水泥的化学成分组成类似,但SiO₂、Al₂O₃含量较高,而CaO含量较低。再生微粉内掺替代水泥的胶砂抗压、抗折强度均随替代比例的增加呈下降趋势;内掺30%时,再生微粉的强度活性指数可达55%以上,说明再生微粉具有一定的凝胶活性。此外,底渣再生微粉的掺加对胶砂早期强度的影响较小,随再生微粉掺量的增加,胶砂强度前期增长速度变慢,后期强度出现较大幅度的降低。     

Comparison between laboratory and field leachability of MSWI bottom ash as a road material

The leaching properties of bottom ash from municipal solid waste incineration (MSWI) used as an aggregate substitute in unbound pavement layers are evaluated. The mechanical behaviour of bottom ash is acceptable for this application, but the potential environmental consequences constitute the most important limitation on the use of bottom ash as a road material. The environmental properties of bottom ash are assessed by means of the Dutch availability test NEN 7341 and the single-batch and two-stage batch European EN 12457 laboratory leaching tests. Furthermore, an experimental unbound pavement stretch is constructed to provide information on leaching behaviour under field conditions. In this high infiltration scenario, the results from predicted (based upon laboratory leaching tests) and measured releases (under field conditions) are compared, evidencing that predictions based on compliance leaching tests may be highly realistic. The depletion period of the extractable fraction of a number of elements in these field conditions is also quantified.     

利用城市生活垃圾焚烧炉渣制备蒸压加气混凝土板材

以城市生活垃圾焚烧炉渣和石英尾矿作为蒸压加气混凝土板材的硅质原料,通过设计工艺配方和工艺参数控制,采用XRD和SEM对原料和试块的矿物相组成和微观形貌进行分析并测试相关的物理性能.试验研究表明:当工艺配比中焚烧炉渣:石英砂:石灰:水泥:石膏为39％:30％:15％:13％:3％时,所制作的砌块抗压强度符合GB11968...     

Environmental assessment of a road site built with MSWI residue

A 23-year-old road built with MSWI residue (mix of fly and bottom ashes) was investigated through the environmental assessment of the residue, soils (adjacent to and underlying the road) and seepage waters. The pH and ANC_4.3 of the material indicate a low carbonation and a high alkaline stock. The material leaches few trace elements. The underlying road soil shows significant effects with respect to K and Na, attributable to the MSWI residue. Effects regarding Cd, Cr, Cu and Ni are observed, yet pollution thresholds are not exceeded. Compared to groundwater thresholds, the MSWI residue percolate is of poor to very poor quality (French reference system — FWQAS) in terms of pH, K, Na, Cl⁻, F⁻, As and Cu. It lies above the intervention values of the Dutch Soil Protection Act (DSPA) for Cu, Ni and Pb. Downstream, water from the road shoulder (W_Sdr) is of very poor quality with respect to Na and Cl⁻, and fair to poor quality regarding K. All other parameters comply with the best quality thresholds (FWQAS and DSPA). The high Cl⁻ concentration of W_Sdr would not fit for direct discharge in any watercourse. Toward a weakly-mineralised water, Cd and Cu would also be penalizing. The geometry of the road site creates penalizing conditions increasing the washing of the MSWI residue. The road structure does not cause downstream effect as regards trace elements, but effects exist for Cl⁻, Na and K. Opposite downstream effects are observed (Ca, Mg, Mn and SO₄²⁻) due to farming treatments and the nature of the local soil.     

生活垃圾焚烧炉渣制砖技术及产业化研究

研究的目的是利用生活垃圾焚烧后产生的炉渣作为骨料,生产免烧砖,实现生活垃圾焚烧炉渣的资源化利用。     

Utilization of municipal solid waste incineration ash in stone mastic asphalt mixture: Pavement performance and environmental impact

The objective of this study is to the use of municipal solid waste incinerator (MSWI) fly ash as a partial replacement of fine aggregate or mineral filler in stone matrix asphalt (SMA) mixture. For saving natural rock and reusing solid waste, basic oxygen furnace slag (BOF slag) was used as part of coarse aggregate. And this makes SMA mixtures contain more than 90% solid waste materials by mass. A comparative study of the performance of two mixes designed using superior performance asphalt pavements (SUPERPAVE) and Marshall mix design procedures was carried out in this research. Samples from both mixes were prepared at the design asphalt contents and aggregate gradations and were subjected to a comprehensive mechanical evaluation testing. These tests included Marshall stability, water sensibility, resilient modulus, fatigue life and rutting. In all the performed tests SUPERPAVE mixtures proved their superiority over Marshall mixtures. TCLP test for environmental impact indicated that asphalt is an effective stabilization and solidification agent for heavy metal in MSWI ash. The heavy metal leachates in TCLP tests have great positive correlation with their initial concentration in waste. But Ni is an exception that lower initial concentration leaded to higher cumulative leaching rate.     

Physical and mechanical properties of municipal solid waste incineration residues with cement and coal fly ash using X-ray Computed Tomography scanners

A significant volume of Municipal Solid Waste incineration bottom ash and fly ash (i.e., incineration residues) are commonly disposed as landfill. Meanwhile, reclamation of landfill sites to create a new land space after their closure becomes an important goal in the current fewer and fewer land availability scenario in many narrow countries. The objective of this study is to reclaim incineration residue materials in the landfill site by using cement and coal fly ash as stabilizers aiming at performing quality check as new developed materials before future construction. Indeed, physical and mechanical properties of these new materials should be initially examined at the micro scale, which is the primary fundamental for construction at larger scale. This research examines quantitative influences of using the combination of cement and coal fly ash at different ratio on the internal structure and ability of strength enhancement of incineration residues when suffering from loading. Couple of industrial and micro-focus X-ray computed tomography (CT) scanners combined with an image analysis technique were utilized to characterize and visualize the behavior and internal structure of the incineration residues-cement-coal fly ash mixture under the series of unconfined compression test and curing period effect. Nine types of cement solidified incineration residues in term of different curing period (i.e., 7, 14, 28 days) and coal fly ash addition content (i.e., 0%, 9%, 18%) were scanned before and after unconfined compression tests. It was shown that incineration residues solidified by cement and coal fly ash showed an increase in compression strength and deformation modulus with curing time and coal fly ash content. Three-dimension computed tomography images observation and analysis confirmed that solidified incineration residues including incineration bottom and fly ash as well as cement and coal fly ash have the deliquescent materials. Then, it was studied that stabilized parts play a more important role than spatial void distribution in increment or reduction of compression strength.     

城市生活垃圾焚烧炉渣的三轴试验研究

采用常规三轴试验,测试了饱和炉渣的剪切强度,分析了饱和炉渣的破坏模式和强度随龄期的变化规律,结果表明:围压小的试验中,饱和试样破坏模式为脆性破坏;围压大的试验中,饱和试样破坏模式为塑性破坏;饱和试样的内摩擦角基本不随龄期变化,粘聚力随龄期增加而增加。     

Geo-environmental application of municipal solid waste incinerator ash stabilized with cement

The behavior of soluble salts contained in the municipal solid waste incinerator (MSWI) ash significantly affects the strength development and hardening reaction when stabilized with cement. The present study focuses on the compaction and strength behavior of mixed specimens of cement and MSWI ash. A series of indices such as unconfined compressive strength, split tensile strength, California bearing ratio (CBR) and pH value was examined. Prior to this, the specimens were cured for 7 d, 14 d, and 28 d. The test results depict that the maximum dry density (MDD) decreases and the optimum moisture content (OMC) increases with the addition of cement. The test results also reveal that the cement increases the strength of the mixed specimens. Thus, the combination of MSWI ash and cement can be used as a lightweight filling material in different structures like embankment and road construction.     

Treatment of leachate from MSWI bottom ash landfilling with anaerobic sulphate-reducing process

Removal of sulphate and toxic elements from the leachate of a field landfill lysimeter (112m(3)), containing municipal solid waste incineration (MSWI) bottom ash, was studied. The leachate was treated in two parallel laboratory upflow anaerobic sludge blanket (UASB) reactors without and with ethanol as additional carbon source. With ethanol more than 65% of sulphate was removed, while without ethanol removal was negligible. The treatment removed Ba, Ca, Cu, Mn, Mo, Ni, Pb, Tl, Sb, Se, Sr, and Zn of the studied 35 trace and other elements. The sequential extraction of the reactor sludge at the end of runs confirmed that with a few exceptions (Ba, Ca, and Cu) the main mechanism by which the elements were removed was precipitation as sulphides.     

Spatial modelling of gaseous emissions from two municipal solid waste dump sites

This paper reports the spatial modelling of gaseous emissions from two municipal solid waste dump sites to determine exposure to landfill gases. The AERMOD modelling software and the Mexican Biogas Model were used, with information from nearby meteorological stations for the period 2015–2016. It was observed that, at one of the dump sites, gas emissions reach populated areas, but in concentrations too low to be detected by the olfactory pathway (benzene <5 µg/m³, toluene and xylene <50 µg/m³). At the second dump site, concentrations are greater; there are no population settlements close by. The highest concentrations of benzene, toluene, xylene and hydrogen sulphide are found within, or around, the dump sites, reaching levels greater than 38 μg/m³ for benzene, 770 μg/m³ for toluene and 237 μg/m³ for xylene.     

Biomonitoring of the genotoxic potential of aqueous extracts of soils and bottom ash resulting from municipal solid waste incineration, using the comet and micronucleus tests on amphibian (Xenopus laevis) larvae and bacterial assays (Mutatox and Ames tests)

The management of contaminated soils and wastes is a matter of considerable human concern. The present study evaluates the genotoxic potential of aqueous extracts of two soils (leachates) and of bottom ash resulting from municipal solid waste incineration (MSWIBA percolate), using amphibian larvae (Xenopus laevis). Soil A was contaminated by residues of solvents and metals and Soil B by polycyclic aromatic hydrocarbons and metals. MSWIBA was predominantly contaminated by metals. Two genotoxic endpoints were analysed in circulating erythrocytes taken from larvae: clastogenic and/or aneugenic effects (micronucleus induction) after 12 days of exposure and DNA-strand-breaking potency (comet assay) after 1 and 12 days of exposure. In addition, in vitro bacterial assays (Mutatox and Ames tests) were carried out and the results were compared with those of the amphibian test. Physicochemical analyses were also taken into account. Results obtained with the amphibians established the genotoxicity of the aqueous extracts and the comet assay revealed that they were genotoxic from the first day of exposure. The latter test could thus be considered as a genotoxicity-screening tool. Although genotoxicity persisted after 12 days' exposure, DNA damage decreased overall between days 1 and 12 in the MSWIBA percolate, in contrast to the soil leachates. Bacterial tests detected genotoxicity only for the leachate of soil A (Mutatox). The results confirm the ecotoxicological relevance of the amphibian model and underscore the importance of bioassays, as a complement to physico-chemical data, for risk evaluation.     

MSWI炉渣-矿渣复合水泥的性能研究

将MSWI炉渣与矿渣作为辅助胶凝材料引入水泥系统当中,并对复合水泥的强度性能及其重金属浸出毒性进行了研究。试验结果表明:单掺炉渣、矿渣时,掺量越高,复合水泥胶砂强度越低,当炉渣与矿渣复掺后,炉渣中的碱离子能激发矿渣的活性,使强度降幅减小,且在炉渣/矿渣质量比为1∶2~1∶4时效果达到最佳;Na2SiO3是一种很好的矿渣活性激发剂,但加入MSWI炉渣-矿渣复合水泥中,会降低强度。MSWI炉渣-矿渣复合水泥制品的重金属浸出浓度低于浸出毒性标准限值,不会对环境造成污染。     

Analysis of the genotoxicity of municipal solid waste incinerator ash.

Combined bottom and fly ash obtained from a Chicago, IL, municipal solid waste incinerator (MSWI) was extracted with organic solvents, water or acidified water. The mean amounts of organic material isolated from each extraction procedure were 688.2, 91.8 and 167.7 micrograms/g MSWI ash. These extracts were evaluated for toxicity and mutagenicity in Salmonella typhimurium strains TA98 and TA100. We developed and calibrated a micropreincubation assay to evaluate small concentrations of the organic extracts. No direct-acting mutagens were found, however the acid-treated aqueous extracts were toxic. Materials isolated with methylene chloride methanol were mutagenic after hepatic microsomal activation (S9). The mutagenic potencies of the organic extract normalized to a per gram ash basis was the induction of 103.46 revertants in TA98 and 247.5 revertants in TA100. The aqueous extracts were neither toxic nor mutagenic. However, the acid-treated aqueous extract was mutagenic to TA100. The organic material isolated from the acidic extract had an induced mutagenic potency of 44.2 revertants/mg extract. Normalizing these data indicate a mutagenic potency of 7.4 revertants/g MSWI ash leached.