Life cycle assessment of waste paper management: The importance of technology data and system boundaries in assessing recycling and incineration

The significance of technical data, as well as the significance of system boundary choices, when modelling the environmental impact from recycling and incineration of waste paper has been studied by a life cycle assessment focusing on global warming potentials. The consequence of choosing a specific set of data for the reprocessing technology, the virgin paper manufacturing technology and the incineration technology, as well as the importance of the recycling rate was studied. Furthermore, the system was expanded to include forestry and to include fossil fuel energy substitution from saved biomass, in order to study the importance of the system boundary choices. For recycling, the choice of virgin paper manufacturing data is most important, but the results show that also the impacts from the reprocessing technologies fluctuate greatly. For the overall results the choice of the technology data is of importance when comparing recycling including virgin paper substitution with incineration including energy substitution. Combining an environmentally high or low performing recycling technology with an environmentally high or low performing incineration technology can give quite different results. The modelling showed that recycling of paper, from a life cycle point of view, is environmentally equal or better than incineration with energy recovery only when the recycling technology is at a high environmental performance level. However, the modelling also showed that expanding the system to include substitution of fossil fuel energy by production of energy from the saved biomass associated with recycling will give a completely different result. In this case recycling is always more beneficial than incineration, thus increased recycling is desirable. Expanding the system to include forestry was shown to have a minor effect on the results. As assessments are often performed with a set choice of data and a set recycling rate, it is questionable how useful the results from this kind of LCA are for a policy maker. The high significance of the system boundary choices stresses the importance of scientific discussion on how to best address system analysis of recycling, for paper and other recyclable materials.     

Environmental Technology Verification (ETV) test of dioxin emission monitors

The performance of four dioxin emission monitors, including two long-term sampling devices, the Dioxin-MonitoringSystem (DMS) and AMESA (the adsorption method for sampling dioxins and furans), and two semireal-time continuous monitors, the resonance ionization with multimirror photon accumulation time-of-flight mass spectrometer (RIMMPA-TOFMS) and the jet resonance-enhanced multiphoton ionization (jet-REMPI) system were tested. A package boiler burning a simulated chlorinated hazardous waste was used for a total of nine tests. Reference samples were collected during each test and analyzed for polychlorinated dibenzodioxins and dibenzofurans (PCDDs/Fs) using gas chromatography mass spectrometry. The PCDD/F concentrations of the reference samples measured by EPA Method 23 ranged from 0.9 to 6.0 ng toxic equivalence (TEQ)/dry standard cubic meter. The relative accuracies achieved by DMS, AMESA, and jet-REMPI varied from 22.6% to 78.2%, with 100% data completeness. The RIMMPA-TOFMS produced no quantifiable results due to various difficulties associated with the instrument during the testing. The two long-term samplers were easy to install and operate and provided a cumulative, averaged emission for the sampling period. The operations of the two semi-real-time continuous monitors were relatively complex, but one of them provided on-site, real-time data for PCDD/F emissions from measurement of a TEQ correlative indicator compound. This article summarizes results from the individual Environmental Technology Verification reports for the four dioxin monitors. This work was presented, in part, at the Fourth International Conference on Combustion, Incineration/Pyrolysis and Emission Control (i-CIPEC)     

排放源烟道气二噁英空间分布对监测结果的影响

针对生活垃圾焚烧企业烟气排放烟囱6个断面单点采样的试验结果,分析按照《固定污染源排气中颗粒物测定与气态污染物采样方法》(GB/T 16157—1996)多断面点采样与单一固定断面点采样对监测结果的影响。试验表明,烟道气在不同断面点质量浓度分布差异较大,相对于样品实际监测值,各断面点二噁英毒性当量浓度最大正偏差达到+306%,最大负偏差达到-96%,测定的18个断面点样品,只有2个样品与实际样品监测值相近。     

浅谈无锡市危险废物产生情况与处置现状

无锡市作为江苏重点发展的城市,随着社会和经济的快速发展,危险废物产生量和种类不断增多。文中针对无锡市2011年—2018年危险废物产生量、综合利用与处置情况,分析危险废物处置利用存在的问题,同时,就目前危险废物存在的问题,提出科学合理的建议。     

焚烧炉气相燃烧工况条件优化的分析与计算

对固体废弃物焚烧过程进行了简要分析，认为设计好气相燃烧工况，使挥发性组分完全燃烧，是控制主要有害有机组分的破坏去除率的关键。计算了（１）在动力控制条件下，不同温度时的多种有机物ＤＲＥ达９９．９９％所需的时间；（２）在扩散控制条件下，不同粒径固体废弃物的不同分析量挥发性组分完全燃烧所需的时间。讨论了炉内温度，气体在炉内停留时间，氧浓度等因素至ＤＲＥ的影响。     

Dioxin removal in “energy from waste plants” - comparison of air pollution control methods

The graph below shows the emitted dioxin - equivalents (Eadon) in grams per year in flue gas from municipal solid waste incinerators with various air pollution control methods for plants of capacity of 200 000 ton municipal solid waste (MSW) per year.

Full-size image (15K)

With optimized combustion and an effective air pollution control system the emissions of dioxins can be kept very low (concentrations below 0.1 ng/m³n).

With a very effective air pollution control system the total emission from all Swedish MSW-incinerators burning approximately 1.5 Mton/year will by 1990 be below 2 g/year - a drastic reduction from approximately 15 g today. As the total dioxin - equivalent emission to the environment in Sweden in the year 1987 was almost 500 g we see that municipal waste incineration really is on the way to solve their dioxin problem.     

深圳市垃圾及其处理的研究

深圳市是中国广东省沿海近１７年发展起来一座现代城市。问题相当突出。其中以垃圾问题的解决的解决难度最大。处理垃圾采用填进地和焚烧方法。按１９９５年计，总量４４５８８８ｔ／ａ，其中直埋量占８６．６３％，焚烧量占１６．３７％，根据我们的研究，这两种方法均在较大问题。现正研究解决这些问题的途径     

模糊数学决策法的改进及在生活垃圾处理方式评价中的应用

对传统的模糊数学法进行了改进，并将其用于城市生活垃圾处理方式的决策评价中。针对上海城市生活垃圾规模处置系统可能有的3种方案分别构造矩阵，求出评价值。结果表明，改进后的模糊数学决策法解决实验问题更合理。     

热重法研究模化城市生活垃圾燃烧和热解特性

利用热重技术研究了模化城市生活垃圾(model municipal solid waste，MMSW)的热解和燃烧过程的特性。结果表明，在小于300℃的温度范围内，热解和燃烧的失重曲线基本一致，不同升温速率对失重特性有影响。利用分峰拟合处理技术对MMSW热处理过程的DSC曲线进行分析，发现MMSW燃烧和热解的失重特性基本上是所含物质失重特性的叠加。对MMSW热处理过程进行动力学分析，计算结果表明反应级数在1．2～1．8之间，化学反应的平均活化能在30～50kJ／mol之间。     

Trace element partitioning in ashes from boilers firing pure wood or mixtures of solid waste with respect to fuel composition,chlorine content and temperature

Trace element partitioning in solid waste (household waste, industrial waste, waste wood chips and waste mixtures) incineration residues was investigated. Samples of fly ash and bottom ash were collected from six incineration facilities across Sweden including two grate fired and four fluidized bed incinerators, to have a variation in the input fuel composition (from pure biofuel to mixture of waste) and different temperature boiler conditions. As trace element concentrations in the input waste at the same facilities have already been analyzed, the present study focuses on the concentration of trace elements in the waste fuel, their distribution in the incineration residues with respect to chlorine content of waste and combustion temperature.Results indicate that Zn, Cu and Pb are dominating trace elements in the waste fuel. Highly volatile elements mercury and cadmium are mainly found in fly ash in all cases; 2/3 of lead also end up in fly ash while Zn, As and Sb show a large variation in distribution with most of them residing in the fly ash. Lithophilic elements such as copper and chromium are mainly found in bottom ash from grate fired facilities while partition mostly into fly ash from fluidized bed incinerators, especially for plants fuelled by waste wood or ordinary wood chips. There is no specific correlation between input concentration of an element in the waste fuel and fraction partitioned to fly ash. Temperature and chlorine content have significant effects on partitioning characteristics by increasing the formation and vaporization of highly volatile metal chlorides. Zinc and cadmium concentrations in fly ash increase with the incineration temperature.