Statistical estimate of mercury removal efficiencies for air pollution control devices of municipal solid waste incinerators

Although representative removal efficiencies of gaseous mercury for air pollution control devices (APCDs) are important to prepare more reliable atmospheric emission inventories of mercury, they have been still uncertain because they depend sensitively on many factors like the type of APCDs, gas temperature, and mercury speciation. In this study, representative removal efficiencies of gaseous mercury for several types of APCDs of municipal solid waste incineration (MSWI) were offered using a statistical method. 534 data of mercury removal efficiencies for APCDs used in MSWI were collected. APCDs were categorized as fixed-bed absorber (FA), wet scrubber (WS), electrostatic precipitator (ESP), and fabric filter (FF), and their hybrid systems. Data series of all APCD types had Gaussian log-normality. The average removal efficiency with a 95% confidence interval for each APCD was estimated. The FA, WS, and FF with carbon and/or dry sorbent injection systems had 75% to 82% average removal efficiencies. On the other hand, the ESP with/without dry sorbent injection had lower removal efficiencies of up to 22%. The type of dry sorbent injection in the FF system, dry or semi-dry, did not make more than 1% difference to the removal efficiency. The injection of activated carbon and carbon-containing fly ash in the FF system made less than 3% difference. Estimation errors of removal efficiency were especially high for the ESP. The national average of removal efficiency of APCDs in Japanese MSWI plants was estimated on the basis of incineration capacity. Owing to the replacement of old APCDs for dioxin control, the national average removal efficiency increased from 34.5% in 1991 to 92.5% in 2003. This resulted in an additional reduction of about 0.86 Mg emission in 2003. Further study using the methodology in this study to other important emission sources like coal-fired power plants will contribute to better emission inventories.     

Characteristics of PCDD/F congener distributions in gas/particulate phases and emissions from two municipal solid waste incinerators in Taiwan

Partitioning of PCDD/F (polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofuran) congeners between gaseous and particulate phases and removal efficiencies of the existing air pollution control devices (APCDs) for PCDD/Fs at two large-scale municipal waste incinerators (MWIs) in Taiwan are evaluated via stack sampling and analysis. Two MWIs investigated are equipped with activated carbon injection (ACI) and selective catalytic reduction system (SCR) as major PCDD/F control devices, respectively. The average PCDD/F concentrations of stack gases are 2.35 and 1.49 ng/N m(3), and the international toxic equivalent quantity (TEQ) are 0.17 and 0.043 ng TEQ/N m(3) in MWI-A and MWI-B, respectively. The average removal efficiency of PCDD/Fs achieved with ACI+BF (bag filters) reaches 95% (MWI-A) while that achieved with the WS (wet scrubber)+SCR system reaches 99% (MWI-B). The results obtained on gas/particulate partitioning in flue gases indicate that particulate-phase PCDD/Fs accounted for 27.7% and 24.7% of the total PCDD/F concentrations at the outlets of cyclone (CY) and electrostatic precipitator (EP) for MWI-A and MWI-B, respectively. But the gas/particulate partitioning in flue gas after PCDD/Fs control devices is quite different in two MWIs. This study also indicates that total 2,3,7,8-substituted PCDD/F discharges are 142.3 microg TEQ/ton waste for MWI-A and 98.6 microg TEQ/ton waste for MWI-B, respectively.     

报告之二：综合利用城市垃圾等废弃物的绿色水泥

一、水泥生产使大量废弃物变废为宝并改善了水泥性能可用于水泥的工业废渣有如下六大类数十种:1、潜在水硬性的废渣。如锰铁矿渣、化铁矿渣、铁渣、赤泥、粒化电炉磷渣,增钙流态渣等。2、具有火山灰性的废渣。如粉煤灰、煤歼石,沸腾炉渣、液态渣、煤渣、硅灰、废砖瓦。3、具有水硬性的废渣。如铜矿渣等。4、具有气硬性的废渣。如磷石膏、氟石膏、盐田石膏,环保副产品石膏、电石渣等。5、惰性或低活性废渣。如含钛矿渣、钢渣、硫铁矿渣、硫铁尾矿渣。铅锌尾矿石。6、其他废渣。如客灰、硫酸渣、碱渣、矾泥等。二、可燃废弃物替代水泥烧成燃料…     

城市固体废弃物(MSW)的工程性质

填埋是处理城市固体废弃物（ＭＳＷ）的主要方法，对现代卫生填埋场进行设计和审查时均需进行广泛的土工分析，正确选择废弃物的工程性质对填埋场设计工作极其重要。由于ＭＳＷ构成极不均匀，其工程性质变化范围很大，并随时间而变，而且很难进行直接量测。本文根据收集到的资料，给出了ＭＳＷ某些工程性质如容重、含水量、孔隙率、渗透性、持水率、凋蔫湿度、抗剪强度和压缩性等的典型值，可供现代卫生填埋场进行初步工程评价时作参考。     

Stiffness parameters of municipal solid waste

This paper presents results of the deformability parameters of municipal solid waste (MSW) determined through laboratory (oedometer and triaxial tests) and in situ tests [standard penetration tests (SPT) and cone penetration tests (CPT)], as well as by a monitoring system including topographic control marks, open-tube piezometers, earth and pore pressure cells and inclinometer tubes with magnetic settlement plates and spiders. The studied landfill is located in a textile industry area, and was landfilled with some direct waste (10 %) and mostly pre-treated waste (90 %, from composting and triage). The influence of: the waste age, construction phase of the landfill and confining stress on the results of stiffness modulus, lateral waste pressure coefficient at-rest (K ₀) and Poisson’s ratio (ν) are presented, as well as an attempt to establish correlations to estimate MSW stiffness modulus from SPT and CPT tests. The results indicate the increases of K ₀ and ν with the average effective confining stresses during the first 2 years of the post-construction phase, reaching maximum values of 0.7 for K ₀ and 0.4 for ν, and then decreasing gradually until stabilizing at values of around 0.23–0.48 for K ₀ and around 0.19–0.32 for ν. The stiffness modulus values determined by different methods are consistent with each other and corroborate the fact that typical values for MSW are low. These values are between 0.4 and 2 MPa for a mean confinement stress of about 50 kPa, and tend to increase linearly with the increase of the confinement stress. The correlations established with SPT and CPT tests are of the same type as usually proposed for granular soils; however, the constant values are significantly lower than the lowest values reported for normally consolidated sandy soils.     

城市生活垃圾中优先流规律的穿透试验研究

城市生活垃圾具有大孔隙特性,优先流是垃圾中水分运动的重要形式,目前垃圾中优先流基本规律尚不明确,优先流数值分析时相关参数的选取尚缺乏依据。通过垃圾柱穿透试验研究城市生活垃圾中的优先流,以Cl-为示踪剂,进行了不同埋深和龄期试样、不同高度试样和不同入渗强度的穿透试验,得到溶质穿透曲线,运用对数正态分布模型和双峰概率密度模型拟合试验结果,定量分析了垃圾中优先流规律。结果表明,通过大孔隙运移的溶液占比在55%~70%之间,垃圾中优先流现象明显。随着垃圾的埋深和龄期增加,参与溶质运移的孔隙比例增加,但通过大孔隙运移的比例减少,优先流程度降低;试样高度增加,参与溶质运移的孔隙比例增加,但其内部大孔隙贯通性变差,通过大孔隙运移占比减小,优先流程度降低;入渗强度增大,参与溶质运移的大孔隙占比增加,优先流程度增大。双峰概率密度模型比对数正态分布模型能更好地描述垃圾中溶质运移的优先流规律,同时为使用两域模型进行垃圾水分运移分析时的参数取值提供了依据。     

Burden of disease attributable to air pollutants from municipal solid waste incinerators in Seoul, Korea: a source-specific approach for environmental burden of disease

Few studies have attempted to quantify the integrated health burden, incorporating both mortality and morbidity as these factors pertain to air pollutants, on the population in the vicinity of the incinerators. The aims of this study are to estimate the attributable burden of disease caused by incinerators in Seoul, Korea and to present an approach based on source-specific exposure for the estimation of the environmental burden of disease (EBD). With particular attention on the development of a measurement means of the source-specific, exposure-based population attributable fraction (PAF), we integrated air dispersion modeling, Geographic Information Systems (GIS), the population distribution of exposure, and the exposure-response relationship. We then estimated the PAFs caused by additional concentrations of four air pollutants (PM₁₀, NO_2, SO₂, and CO) emitted from four municipal solid waste incinerators (MSWIs) in Seoul in 2007. We, finally, estimated the attributable burden of disease, using the estimated PAF and the disability-adjusted life years (DALY) method developed by the Global Burden of Disease Group of the World Health Organization (WHO).The PAF for NO₂ to all-cause mortality was assessed at approximately 0.02% (95% CI: 0.003-0.036%), which was the highest among all air pollutants. The PAFs for respiratory and cardiovascular disease were 0.12% (95% CI: 0.01-0.16%) and 0.10% (95% CI: 0.04-0.16%), respectively. The sum of the attributable burden of disease for four pollutants was about 297 person-years (PYs) (95% CI: 121-472 PYs) when the incinerators observed to the emission standards. The attributable burdens of respiratory disease and cardiovascular disease were about 0.2% and 0.1%, respectively, of the total burden of respiratory disease and cardiovascular disease of Seoul citizens for the year 2007. Although the air emissions from one risk factor, an incinerator, are small, the burden of disease can be significant to the public health when population exposure is considered.     

城市生活垃圾降解-压缩特性试验研究

为了研究垃圾土在好氧和厌氧阶段因外部温度场的变化对降解特性的影响,选取重庆市某垃圾场作为研究对象,进行了两种不同温度控制的降解试验,同时对渗滤液中可溶解有机碳含量进行了追踪测试,试验结果表明：①不同有机物含量垃圾土试样,当外部温度场小于22℃或者大于45℃时,温度对有机质降解的影响较小;②当温度在22℃~45℃时,根据垃圾土产气量、渗滤液溢出量以及质量损失率得出此温度区间对垃圾中有机质的降解起明显加速作用,降解反应程度在41℃时最大;③根据温度-质量损失率关系,推导了考虑温度效应的分阶段垃圾土降解率计算模型,并且得出垃圾土的降解率在0~180 d符合自然降解规律,为时间的函数;在180~360 d,降解率为时间和温度的双重函数;模型验证结果表明,计算结果与试验结果能够比较好的吻合。     

城市固体废弃物动力特性试验研究

参照杭州天子岭填埋场城市固体废弃物(MSW)主要成分,人工配制固体废弃物试样,利用中型动三轴试验仪研究其在较大应变范围内MSW的动力特性。MSW的动剪切模量Gd和阻尼比D随着动剪应变γd的变化曲线与泥炭土的相关曲线形状基本一致,并且在相同应变时数值相差不大。在相同的动剪应变水平下,随着围压的增大,Gd增加而D减小;当动剪应变增大时,Gd减小而D增大。由于MSW的高压缩性,初始孔隙比不同对试样的动力特性影响不大。同时进行了现场剪切波速试验,确定了最大动剪切模量Gdmax的估算式。为便于应用,建议了归一化Gd和D与动剪应变依赖关系的取值范围和平均值曲线,并将其与OII填埋场MSW动力特性的研究结果进行对比,可以看出MSW的成分对其动力特性的影响还是比较大。     

垃圾土电阻率特性试验研究

以重庆市长生桥垃圾填埋场作为研究对象,基于垃圾土颗粒导电性分类,通过室内试验测试了不同因素(添加不同溶液、孔隙率、含水率、温度等)影响下垃圾土电阻率变化特征。试验结果表明:当垃圾土中添加渗滤液、Na Cl、Zn Cl2和柴油4种溶液时,垃圾土电阻率随垃圾土中孔隙率的增加均呈递减趋势;孔隙率一定时,随含水率的增加垃圾土中固液并联导电在垃圾土导电通路中的比例增大;渗滤液对垃圾土电阻率的影响在一定程度上受稀释作用控制,且随含水率的增加而减小;随着温度的升高,垃圾土的电阻率呈指数函数衰减趋势;含水率一定时,孔隙率的变化将引起垃圾土中3种导电模式的互相转化,且电阻率随孔隙率的增加呈幂函数减小趋势;利用高密度电阻率层析技术,对现场垃圾填埋体进行了电阻率实测,同时结合室内试验测试结果对电阻率剖面进行了分析;研究结果可为分析因降解引起的垃圾填埋体中渗滤液的富集状态和运移途径的变化,以及评价垃圾土内部结构的演化提供理论支持。     

Estimation of heavy metal transformations in municipal solid waste

The behaviour of heavy metals bound to municipal solid waste (MSW) and exposed to 2 decades of anaerobic waste stabilization processes have been estimated. Heavy metal solid forms in a waste degradation residue have been compared with a reconstructed waste similar to that initially disposed of in 1973. The initial waste was composed of a mixture of shredded MSW (95% dry wt.) and anaerobic sewage sludge (5% dry wt.). A sequential chemical extraction method has been used to fractionate the heavy metals into five categories of available and reactive solid forms. The results imply that these forms can be ascribed to approximately 30% of the total content of the heavy metals in the degraded waste and the portion of heavy metals bound to oxidizable solid forms seems to be higher in the degraded than the fresh MSW. The bulk of the remaining heavy metals are assumed to be less available and bound into resistant lattice structures, such as metal and polymer items. A comparison between fractionation patterns of the waste in this study and of a few sediments collected from different environments imply similarities between the fresh MSW and an oxic sediment from one site and the sewage sludge and anoxic sediments from another site. Fractionation patterns of the degraded waste are found to be quite similar to those of the anoxic sediments, except for Pb, Ni and Cd which are more similar to fresh MSW.     

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...     

A model for de novo synthesis and decomposition rates of dioxins and furans in municipal waste incinerators

We present a concise summary of a de novo synthesis model for the rates of formation of dioxins and furans in incinerators. Representative numerical results are used to illustrate numerical predictions and their utilization.     

Evaluation and prediction of emissions from a road built with bottom ash from municipal solid waste incineration (MSWI)

In autumn 2001, a full-scale test road was built with municipal solid waste incineration (MSWI) bottom ash at the D?vamyran landfill, Ume?, Northern Sweden. Leachates were collected from asphalted sections with either bottom ash or gravel as filling material. In this research, 12 months of ash leachate sampling were evaluated with respect to emissions of contaminants such as trace metals and chlorides (Cl). The usefulness of regression models describing trace metal mobility from bottom ash was also tested as predictive tools for reusability applications of MSWI bottom ash. Cl, Cu, and Cr had the highest mobility (considering leachate concentrations) in the ash leachate, though concentrations of Cl and Cu decreased during the sampling period (Cl from 10,000 to 600 mg l(-1); Cu from 1600 to 500 microg l(-1)). An increased mobility of Cr during the autumns (about 3-4 times higher compared to the summer) was noted with a maximum value of nearly 70 microg l(-1) during autumn 2001. Pb showed a very low mobility over the entire year with leachate concentrations of around 3-4 microg l(-1). Chemical equilibrium calculations using Minteq indicated that several Cu minerals were oversaturated in the leachate, thus mineral precipitation could be responsible for declining amounts of Cu in the leachate. Adsorption to iron oxides was found to be a probable explanation for the low mobility of Pb. A reasonably good agreement between regression models and field values were achieved for Ni, Pb, Zn, and Cu, while the models for Cd and Cr were less promising. Even though a large part of the variation (R2=61-97%) in the leaching experiment could be explained by only pH and L/S, field data were much more scattered than expected from field pH.     

固体废弃物压缩特性及填埋场沉降研究

0 前 言 固体废弃物由多种成分组成,各种成分的差异很大,其中的塑料、纸张、纤维等是固体废弃物具有高孔隙比的主要原因。国外学者 Sowers[1],Landva andClark[2],Mohammed A et al[3]及国内学者钱学德[4]、朱向荣[5]、柯翰[6]、施建勇[7]等对固体垃圾的压缩性进行了试验研究,Yen and Scanlon[8],Edil et al[9],Hoe ILing[10],赵由才[11]等人结合具体填埋场工程进行了沉降的实测研究,提出了沉降与时间的关系,即沉降模型。纵观前人的研究成果,虽然取得了较大的成绩,但作为垃圾压缩稳定的试验标     

重庆市城市生活垃圾的蠕变特性研究

首先以分别加载的方式对以重庆市城市生活垃圾典型组分为依据配制的垃圾试样进行不同应力水平的室内压缩蠕变试验,进而根据蠕变元件的基本性质和试验过程中试样反映出的变形特征,利用HK和PTH蠕变模型对生活垃圾的蠕变曲线进行拟合,并总结得出蠕变模型的基本参数。研究表明,HK和PTH模型对试验数据的拟合程度都比较好,此两种模型对于垃圾填埋场的容量计算和沉降规律研究具有一定的参考价值。     

城市固体废弃物残余变形特性试验研究

利用中型动三轴仪,对城市固体废弃物（MSW）进行了残余变形试验研究,采用改进的沈珠江模型对MSW的残余变形模型参数进行拟合,在此基础上,讨论了不同破坏标准下的应力水平对模型参数的影响,建议了适合MSW的残余变形模型应力水平指数。MSW属于应变硬化型材料,应力和应变曲线没有明显的峰值,不同破坏标准条件下,相同固结比的MSW具有不同的应力水平,因此建议用固结应力比来代替应力水平,提出了适用于MSW的残余变形修改模型,修改后的模型不必考虑破坏标准对残余变形参数的影响,应用更加方便。     

Bioreactivity of leachate from municipal solid waste landfills - assessment of toxicity

With the UK producing 400 million tonnes of waste each year, the problem of waste disposal is recognised as one of the most serious environmental problems facing the nation. Of this, over 35 million tonnes is municipal waste, largely derived from households, but also includes some commercial and industrial waste. There are strong national and international concerns about the possible adverse health effects of living in the vicinity of municipal waste landfills. An understanding of the ranges of toxicity of landfill emissions is crucial to determine the degree of concern we should have about the potential effects they could have upon nearby populations and the surrounding environment. Leachates from three different types of landfills have been collected and screened for their potential to induce toxicity. Bioreactivity was measured by a plasmid DNA scission assay (PSA), and 2',7'-dichlorodihydrofluorescin fluorescence (DCFH). The results indicate that leachates cause damage to plasmid DNA in a dose-dependent manner and that toxicity varies between different types of landfills as well as within individual waste sites. Overall, the data implies that the complex chemistry involved in leachate formation has yet to be delineated in terms of the toxicological response.     

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.     

Assessing eco-productivity change in Chilean municipal solid waste services

The management of municipal solid waste (MSW) is a public service that affects the environment and public health. This study sought to assess the eco-productivity change (i.e., temporal dynamics of eco-efficiency) of a sample of municipalities in the provision of MSW management services. The Malmquist-Luenberger Productivity Indicator (MLPI) and its drivers, namely eco-efficiency and technical changes, were employed to estimate the eco-productivity change of each municipality. The empirical application was examined in 313 Chilean municipalities from to 2015–2019. Based on the results, on average, Chilean municipalities improved their eco-productivity, with eco-efficiency change being the main driver of this improvement.