Plasma-Assisted Treatment of Municipal Solid Waste: A Scenario Analysis

Small-scale thermal treatment of municipal solid waste (MSW) was investigated using mass and energy balances based on the assumption of thermodynamic equilibrium. A typical average MSW composition from the literature was used as basis for modelling of a one ton per day waste gasification facility (plant). Syngas production by pyrolysis, stoichiometric O₂ addition and auto-thermal (gasification with oxygen and/or air where no external heat input is required) combustion were considered. These cases were evaluated for production of electricity only, and steam. From purely thermodynamic considerations, it was observed that auto-thermal oxygen gasification produces the most electricity (47.00 kWe) and oxygen plasma gasification produces a positive net amount (4.07 kWe) on a 1 ton per day scale. Although auto-thermal air gasification also produces a net positive amount, the calorific value of the syngas is too low to fuel an internal combustion engine. As expected, the amount of steam generated by the different scenarios is high due to higher process efficiencies. The close-coupled auto-thermal oxygen process proved to be the most efficient. The cost of additional oxygen generation was however not taken into account, and may change the picture significantly.     

Municipal Solid Waste Landfill Leachate Treatment and Electricity Production Using Microbial Fuel Cells

Microbial fuel cells were designed and operated to treat landfill leachate while simultaneously producing electricity. Two designs were tested in batch cycles using landfill leachate as a substrate without inoculation (908 to 3,200 mg/L chemical oxygen demand (COD)): Circle (934 mL) and large-scale microbial fuel cells (MFC) (18.3 L). A total of seven cycles were completed for the Circle MFC and two cycles for the larger-scale MFC. Maximum power densities of 24 to 31 mW/m² (653 to 824 mW/m³) were achieved using the Circle MFC, and a maximum voltage of 635 mV was produced using the larger-scale MFC. In the Circle MFC, COD, biological oxygen demand (BOD), total organic carbon (TOC), and ammonia were removed at an average of 16%, 62%, 23%, and 20%, respectively. The larger-scale MFC achieved an average of 74% BOD removal, 27% TOC removal, and 25% ammonia reduction while operating over 52 days. Analysis of the microbial characteristics of the leachate indicates that there might be both supportive and inhibiting bacteria in landfill leachate for operation of an MFC. Issues related to scale-up and heterogeneity of a mixed substrate remain.     

Energy Recovery from Municipal Solid Waste in Small Communities

The heating values of municipal solid waste generated in three towns with a population of less than 50 000, situated in Galicia (Spain), were measured with a static bomb calorimeter. Samples of raw refuse were burnt either as received or after sorting of the different combustible components. A study was made of samples from controlled and uncontrolled landfills. The calorific values were compared with those corresponding to a commercial residual derived fuel in order to study the possibility of using municipal solid waste as a source of recovered energy. This revised version was published online in July 2006 with corrections to the Cover Date.     

Ethanol Production from the Organic Fraction Obtained After Thermal Pretreatment of Municipal Solid Waste

In this work, the use of organic fraction from municipal solid waste (MSW) as substrate for ethanol production based on enzymatic hydrolysis was evaluated. MSW was subjected to a thermal pretreatment (active hygienization) at 160?°C from 5 to 50 min. The organic fiber obtained after 30 min was used as substrate in a simultaneous saccharification and fermentation (SSF) and fed-batch SSF process using cellulases and amylases. In a fed-batch mode with 25% (w/w) substrate loading, final ethanol concentration of 30 g/L was achieved (60% of theoretical). In these conditions, more than 160 L of ethanol per ton of dry matter could be produced from the organic fraction of MSW.     

Elemental uptake of radish grown near a Municipal Solid Waste dumping site by EDXRF

Radish plant was collected along with root and soil from the nearby area of a Municipal Solid Waste dumping site of the metropolitan city of Kolkata, West Bengal, India and analyzed for a wide range of elements using the EDXRF technique with a ¹⁰⁹Cd point source and a Si(Li) detector. The samples comprized of the root-soil, root and leaves. For quality control purposes, NIST standard reference material (SRM) 1648 Urban Particulate Matter had also been analyzed using the same procedure as for the samples. Concentrations of elements with X-ray energies in the range of 3–20 keV in the soil around the root and their uptake pattern by the root and the leaves have been estimated.     

生活垃圾释放挥发性有机化合物的仪器分析方法研究进展

综述了国内外生活垃圾样品的采集及仪器分析方法,比较了各种方法的优劣,同时列举了现场仪器检测的应用,以期对我国城市生活垃圾产生的恶臭污染控制提供技术支持.     

X射线荧光光谱法测定垃圾焚烧炉渣中主要成分

使用X射线荧光光谱仪,采用粉末直接压片制样,以研磨的方式克服粉末样品的粒度效应,理论α系数法校正基体效应,建立了垃圾焚烧炉渣样品中SiO2、Fe2O3、MgO、Al2O3、CaO、K2O、TiO2、P2O5八组分的分析方法.用标准化法进行强度漂移校正,用内控标样制做校准曲线,测定结果的精密度和准确度可以满足日常分析要求.     

用铝粉与生活垃圾焚烧底灰制备复合材料的试验研究

以生活垃圾焚烧底灰为增强相,用液相烧结粉末冶金方法,对制备废旧金属铝/生活垃圾焚烧底灰复合材料进行了试验研究.结果表明:当废旧金属铝与生活垃圾焚烧底灰配比为8:2,烧结温度为900℃,保温时间为1.5h,在纯N2保护性气氛的条件下制得的复合材料具有良好的机械性能.如热膨胀系数为0.3×10-6,密度为2.43g/cm3,弹性模量为3014.3Mpa,耐磨性能比铝镁合金的提高了1.3倍.     

Influence of a Municipal Solid Waste Landfill on the Soil Levels of Heavy Metals at Adjacent Territories

Russian Journal of General Chemistry - The levels of heavy metals (Cr, Cu, Zn, Ni, Pb) in the soils of the areas adjacent to the Sharra municipal solid waste landfill located about 7 km...     

A Sequential Extraction Method Measures the Toxic Metal Content in Fly Ash from a Municipal Solid Waste Incinerator

The purpose of this research was to develop an optimized pretreatment procedure for toxic metals (Pb, Cd, Zn and Cu) content in fly ash from a municipal waste incinerator. In addition, modified sequential extraction procedures were used to characterize the chemical composition of the fly ash samples. The sequential extraction resolved the fly ash elements into the following chemical forms: soluble, exchangeable, carbonate, oxide, organic, and silicate compounds. Certified reference city waste incineration ash (BCR.176) was used as target ash samples. A H₂O₂+HNO₃+HF mixed acid digestion solution with a low temperature evaporation procedure was selected as optimal for the fly ash digestion. The digested solution was analyzed by inductively coupled plasma mass spectrometry (ICP‐MS), which effectively determined the concentrations of the toxic metal elements in BCR.176. Except for Cd, the recovery of Pb, Zn, and Cu under H₂O₂+HNO₃+HF digestion and their sequential extraction procedures were higher than 95%. The relative standard deviations (RSD) for recoveries of the four elements were within 10%. Furthermore, the sequential extraction procedure's results provided information on the potential mobility of the studied elements. Most of the Cd was bound to water‐soluble and carbonate material in the fly ash samples. Most of the Pb, Zn, and Cu was released to carbonates and bound to organic matter in the fly ash samples.     

An Insight into the Anaerobic Co-digestion of Municipal Solid Waste and Food Waste: Influence of Co-substrate Mixture Ratio and Substrate to Inoculum Ratio on Biogas Production

Applied Biochemistry and Biotechnology - The unbalanced nutrients of municipal solid waste (MSW), particularly high carbon contents, were regarded as a major limiting factor to anaerobic digestion...     

HRGC-LRMS测定垃圾焚烧炉布袋飞灰中的二噁英类物质

利用高分辨气相色谱-低分辨质谱(HRGC-LRMS)测定了某垃圾焚烧厂布袋飞灰中的二(口恶)英类物质,结果表明对于测定二(口恶)英类浓度相对较高的垃圾飞灰而言,采用HRGC-LRMS是一种可行的方法,回收率在74％～114％之间。该飞灰样品中以二(口恶)英为主,呋喃的含量相对较低,二(口恶)英／呋喃值为4.6,二(口恶)英类物质总量为211.7ng／g,折算到毒性当量为0.69ngI-TEQ／g。     

Determination of Organochlorine Pesticides and Polychlorinated Biphenyls Residues in Municipal Solid Waste Compost by Gas Chromatography with Electron−Capture Detection

A simple and efficient method for the simultaneous gas chromatographic determination of ten organochlorine pesticides (α-HCH, β-HCH, γ-HCH, p,p’-DDT, o,p’-DDT, p,p’-DDD, p,p’-DDE, aldrin, endrin, and dieldrin) and six congeners of PCBs (PCB 28, 52, 118, 138, 153, and 180) in municipal solid waste compost is described. The procedure involves a solid-phase dispersion matrix using celite as dispersant sorbent, alumina as clean up sorbent and hexane-dichloromethane (7:3, v/v) mixture as eluting solvent. An additional purification step with copper was necessary to eliminate sulphur. Analysis of the sample was performed by GC-ECD. The method was validated with fortified samples at two concentration levels (0.025 and 0.05 mg kg^?1). Average recovery ranged from 77 to 121% with relative standard deviation between 1 and 18%. The detection limits, which ranged from 0.003 to 0.01 mg kg^?1, were lower than those established by the Baden–Württemberg directive (0.033 mg kg^?1).     

Gasification of Municipal Solid Wastes in Plasma Arc Medium

Many thermal processes have been developed in order to eliminate the municipal solid wastes or produce energy from them. These processes include a wide range of applications from the simplest burning system to plasma gasification. Plasma gasification is based on re-forming of molecules after all molecules convert to smaller molecules or atoms at high temperatures. In this work, the production of fuel gas is aimed by plasma gasification of municipal solid wastes in high temperatures. Because of this, a plasma reactor of the capacity of 10 kg h^?1 was designed which can gasify municipal solid wastes. Plasma gasification with and without steam and oxygen was performed in temperatures of 600, 800, 1000, 1200, 1400 and 1600 °C in the reactor. A gas mixture containing methane, ethane, hydrogen, carbon dioxide and monoxide, whose content varies with temperature, was obtained. It was found that plasma gasification (or plasma pyrolysis, PG), plasma gasification with oxygen (PGO) and plasma gasification with steam (PGS) were more prone to CO formation. A gas product which was consisted of 95% CO between 1200 and 1400 °C was produced. It was observed that a gas with high energy capacity may be produced by feeding oxygen and steam into the entrance of the high temperature region of the reactor.

     

An Opportunity for Recycling Semi‐dry Scrubber Residues Directly from Municipal Solid Waste Incineration Plants without Concern of Leaching Toxicity

The leaching behaviors of heavy metals from semi‐dry scrubber (SDS) residues of municipal solid waste incineration (MSWI) plants are re‐investigated. The most leachable heavy metals in semi‐dry scrubber residues from municipal solid waste incinerators are found to be chromium ions (Cr(III) and Cr(VI)), but neither lead nor cadmium. Both of the leachabilities of Cr(III) and Cr(VI) in MSWI scrubber residue are a function of the CaO/Al₂O₃ ratio of residues. The pH‐dependent leaching behaviors are only observed in the case of Cr(III), but not for Cr(VI). Our results show that it is worth recycling SDS residues which possess a lower chemical composition ratio of CaO/Al₂O₃, in order to reduce the potential risk of toxic leaching of chromium species.     

Nonequilibrium Vibrational Kinetics during Hypersonic Flow of a Solid Body in Nitrogen and Its Influence on the Surface Heat Flux

Plasma Chemistry and Plasma Processing - Nonequilibrium nitrogen dissociation-recombination kinetics in the boundary layer and on the surface of a solid body during hypersonic flow. the subsequent...     

环境固体废物的监测技术及其应用

介绍了固体废物的特点和分类、我国固体废物监测技术的发展历程及现有固体废物的监测及管理标准体系,在此基础上列举了具有代表性的测定固体废物中污染物的前处理及监测技术应用实例。     

环境固体废物的监测技术及其应用

介绍了固体废物的特点和分类、我国固体废物监测技术的发展历程及现有固体废物的监测及管理标准体系,在此基础上列举了具有代表性的测定固体废物中污染物的前处理及监测技术应用实例。