Release of Fluorocarbons from Insulation Foam in Home Appliances during Shredding

Abstract

It is a current practice that refrigerators and freezers in many countries are shredded after the end of useful lives. The shredder residue is deposited in landfills. During the shredding process a significant fraction of blowing agent (BA) in the insulation foam may be released into the atmosphere. The objective of this study is to determine the fraction of BA released from foam during shredding, by comparing the BA content in insulation foam of refrigerator units before shredding with the BA content of shredded foam. All foam samples analyzed were manufactured with trichlorofluoromethane [CFC-11 (CCl₃F)] as BA. The average content of BA in the insulation foam from eight U.S. refrigerator units manufactured before 1993 was found to be 14.9% ± 3.3% w/w. Several refrigerator units also identified as being manufactured before 1993 were stockpiled and shredded at three shredder facilities, of which one was operated in both wet and dry modes. The selected shredder facilities represent typical American facilities for shredding automobiles, refrigerators, freezers, and other iron containing waste products. Shredded material was collected and separated on location into four particle size categories: more than 32 mm, 16–32 mm, 8–16 mm, and 0–8 mm. Adjusting for sample purity, it was found that the majority (>81%) of the foam mass was shredded into particles larger than 16 mm. The smallest size fraction of foam (0–8 mm) was found to contain significantly less BA than the larger size categories, showing that up to 68% ± 4% of the BA is released from these fine particles during the shredding process. Because only a minor fraction of the foam is shredded into particles smaller than 8 mm, this has a minor impact on the end result when calculating the total BA release from the shredding process. Comparing BA content in shredded samples from the three shredder facilities with the measured average BA content of the eight refrigerator units, it was found that on average 24.2% ± 7.5% of the initial BA content is released during the shredding process.     

Formation characteristics of PCDD and PCDF during pyrolysis processes

In recent years, pyrolysis processes have become technologies developed to industrial scale and discussed as alternatives to the existing waste combustion technology. However, little information is published regarding PCDD/F formation characteristics during pyrolysis processes. Two common shredder fractions – industrial light shredder (ILS) and refrigerators (REF) – both with high chlorine and copper content were pyrolysed for this pyrolysis study using a pilot plant with a capacity of 100 kg/h. At oxygen concentrations below 2% and temperatures between 430°C and 470°C, considerable amounts of PCDD/F were formed during the pyrolysis. More than 90% of total TEQ was found in the oil fraction (gas phase). The PCDD/PCDF ratio and the homologue pattern differed significantly from those formed during waste incineration. Considering mono- to octachlorinated congeners, up to 400 times more PCDF were formed compared to PCDD. For the investigated pyrolysis conditions, the formation of low chlorinated congeners was highly favoured. The distribution of TEQ within the individual congeners were very similar in all investigated runs. More than 80% of total TEQ stem from 2,3,7,8-substituted T₄CDF and P₅CDF. The isomer pattern, however, did not show significant differences compared to the common waste incineration pattern suggesting that the basic formation routes are similar.     

Invertebrates control metal/metalloid sequestration and the quality of DOC/DON released during litter decay in slightly acidic environments

Plant litter and organic sediments are a main sink for metals and metalloids in aquatic ecosystems. The effect of invertebrate shredder (a key species in litter decay) on metal/metalloid fixation by organic matter is described only under alkaline water conditions whereas for slightly acidic waters nothing can be found. Furthermore, less is known about the effect of invertebrate shredders on the quality of dissolved organic carbon (DOC) and nitrogen (DON) released during litter decay. We conducted an experiment to investigate the impact of invertebrate shredder (Gammarus pulex) on metal/metalloid fixation/remobilization and on the quality of DOC/DON released under slightly acidic water conditions. During decomposition of leaf litter, invertebrate shredder facilitated significantly the emergence of smaller particle sizes of organic matter. The capacity of metal fixation was significantly higher in smaller particles (POM 2,000?C63???m) compared to original leaf litter and litter residues. Thus, G. pulex enhanced metal fixation by organic partition of sediments by increasing the amount of smaller particle of organic matter in aquatic ecosystems. In contrast, the capacity of metal/metalloid fixation in the smallest fraction of POM (<63???m) was lower compared with leaf residues in treatment without invertebrates. Remobilization of metals and metalloids was very low for all measured elements. A significant effect of invertebrates on quantitative formation of DOC/DON was confirmed. The quality of released DOC/DON, which may affect metal/metalloid remobilization, was also significantly affected by invertebrate shredders (e.g., more carboxylates). Hence, invertebrate shredder enhanced significantly the fixation of metals/metalloids into POM in slightly acidic environments.     

Pretreatment of automobile shredder residue (ASR) for fuel utilization

Automobile shredder residue (ASR) was pretreated to improve its quality for fuel utilization. Composition analysis revealed that ASR components could be classified into four groups: (1) urethane and textile-light fraction and combustibles containing low levels of ash and Cl; (2) plastics and rubber-light or heavy fraction and combustibles containing high levels of Cl; (3) metals and electrical wire-heavy fraction and incombustibles, and (4) particles smaller than 5.6mm with high ash contents. Based on these results, we successively performed sieving to remove particles smaller than 5.6mm, float and sink separations to reject the heavy fraction and plastics and rubber containing Cl, thermal treatment under an inert atmosphere to remove Cl derived from PVC, and char washing to remove soluble chlorides. This series of pretreatments enabled the removal of 78% of the ash and 91% of the Cl from ASR. Sieving using a 5.6-mm mesh removed a considerable amount of ash. Product quality was markedly improved after the float and sink method. Specifically, the sink process using a 1.1 g cm(-3) medium fluid rejected almost all rubber containing Cl and a large amount of PVC. The remaining Cl in char, after heating at 300 degrees C under an inert atmosphere and washing, was considered to be present as insoluble chlorides that volatilized at temperatures above 300 degrees C. Based on a tradeoff relationship between product quality and treatment cost, ASR may be utilized as a form of refuse plastic fuel or char.     

钢渣掺量对泡沫混凝土砌块性能的影响

泡沫混凝土是一种环保、节能的保温隔热材料，以其优良的保温性能，受到越来越多研究者的关注。对钢渣的特性进行了分析测试，对钢渣不同掺量对泡沫混凝土砌块特性的影响进行了研究，结果表明，采用添加5％～35％钢渣所制备的钢渣泡沫混凝土砌块，其密度等级为JC／T1062—2007中的B10级，掺人5％、15％钢渣的泡沫混凝土抗压强度达到A3．5等级，掺人25％、35％钢渣的泡沫混凝土抗压强度达到A2．5等级。随着钢渣掺量的增大，抗压强度、抗折强度降低，吸水率增大。在同一钢渣掺量的情况下，泡沫混凝土砌块的抗压强度变化率增加显著，而且随着钢渣的加入量升高而增大。钢渣的加入有利于提高泡沫混凝土砌块的后期抗压强度。     

The Petroleum Refining Industry—Air Pollution Problems and Control Methods

Polyurethane foam was incorporated as a prefilter on standard hi-volume samplers of the National Air Sampling Network (NASN) in an exploratory study. The foam selectively filtered particles of various sizes. The characteristics of the particles passing through the foam approached the respirable size fraction as defined by reports of the Atomic Energy Commission. The respirable fraction was then collected on a glass-fiber filter. Parameters such as pore size and thickness of the foam, air flow rates, and loadings were studied to determine their effects on the filtration of “respirable” dust. Ambient air was the particulate source, and sizing was accomplished by an Andersen sampler coupled with nephelometric analyses. Some sizing was also done microscopically. The foam was evaluated at several locations to account for possible variations in ambient air over areas of different industrial complexity.     

利用废CRT屏玻璃为原料制备泡沫玻璃

以废阴极射线管(CRT)屏玻璃为主要原料,碳黑为起泡剂,采用粉末烧结法制备了低密度保温泡沫玻璃。通过扫描电镜(SEM)、导热系数测定仪等分析手段,研究了起泡剂的用量、发泡温度和发泡时间对泡沫玻璃泡径、密度、热学性能以及机械力学性能的影响。结果表明,在相同烧制工艺条件下,随起泡剂掺加量增加,烧制所得的泡沫玻璃密度成"V"型变化;当其掺加量为0.20%时,泡沫玻璃在密度、孔径分布以及力学性能上均达到最佳。随着发泡温度的提高和发泡时间的延长,密度会逐渐减小,泡沫玻璃的气泡会逐渐增大,以致产生连通现象。当发泡温度为820℃、发泡时间为30min时烧制的泡沫玻璃密度为0.180 g/cm3,导热系数为0.0695 W/(m.K)。     

Formaldehyde source interaction studies under whole-house conditions

This study was designed to determine the effect of source combinations on formaldehyde levels under whole-house conditions. Evaluations were conducted on particleboard (applied as subflooring) and hardwood plywood panelling (applied as a wall covering) both singly and in combination, and on urea-formaldehyde foam insulation and particleboard. Formaldehyde source combination/interaction evaluations revealed several different outcomes, including no augmentation of formaldehyde levels, a slight augmentation (30-50%) and complete addivity. Additivity was observed for regular and low emission grade particleboard and hardwood plywood combinations and for urea-formaldehyde foam insulation and particleboard subflooring. In contrast, controlled chamber studies employing samples of the same wood materials revealed no additive effects. Results of these studies raise questions about the reliability of using laboratory evaluations alone to predict formaldehyde levels under real-world residential conditions.     

Remediation of an old landsfill site

The Baltic Sea Region has a large number of landfills that need remediation after care routines and control, in order to avoid future emissions to the environment and to fulfil the demands in the EU Waste Council Directive on the landfill of waste. Based on the Måsalycke test screening, an excavation of whole or of parts of the landfill can be seen as a potential measure for some of the old landfills. The material excavated in the test was screened into the fractions: < 18 mm, 182-50 mm and > 50 mm. The coarsest fraction (> 50 mm) contained 50% wood and paper. The medium-sized fraction (18–50 mm) contained stones and indefinable soil-like material, while the fine fraction contained peat-like material with some other small waste components. The spectral analysis of heavy metals indicated only high concentrations of zinc and there was no significant difference between the fine and the medium-sized fractions. The medium sized and the unsorted fraction was moisturized and refilled into the pit. The methane content in the landfill gas from the pit was 50–57% in the sorted material with a flow of 8–17 l/min and 38–57% in the unsorted fraction with a flow of 2–13 l/min during the first 1.5 year. The Måsalycke landfill is in the methanogenic phase and leachate concentrations are normal. Landfill mining can be used to prolong the landfill lifetime and/or used as a tool for remedial actions in contaminated sites.     

Experimental Evaluation of Waste Tires Utilization in Cement Kilns

ABSTRACT

The present work outlines the main results of a full-scale study conducted on the utilization of waste tires as auxiliary fuel in cement production. Experimental tests were conducted for determining the influence of shredded tires on combustion conditions, emissions produced, and the characteristics of clinker obtained, for feeding ratios over 35% in terms of total heat input. The addition of tire chips did not lead to any appreciable modification in either the whole process or the quality of clinker produced; gaseous emissions were mostly unaffected, with significant improvements related to the reductions obtained in nitrogen and sulfur oxides concentrations. Experimental findings from tests conducted with tire chips exposed to kiln combustion flue gases compare favorably with the typical burnout times derived from theoretical approaches. These experimental data and calculations to estimate particle trajectories beyond the injection point, through proper theoretical analysis of the kinetic behavior, result in important indications for the shredding operation and for optimum injection modes.     

Leaching of Cu and Zn from discarded boat paint particles into tap water and rain water

We studied the leaching of copper and zinc from particles of discarded boat paint added to tap water (pH 7.3) and rain water (pH = 4.7), simulating conditions encountered during the hosing or runoff of antifouling waste. Leaching rates appeared to be diffusion-controlled and were greater in rain water than in tap water and were greater for Zn than for Cu. After a period of 120 h, between about 0.5% and 3% of total Cu and 5-30% of total Zn had been released to the aqueous phase. These observations suggest that Cu and Zn mobilised from fine antifouling particulates during washdown or rainfall events may be important contaminants of runoff and soils in the vicinity of boat repair facilities.     

Electrocatalytic hydrodechlorination of 4-chlorobiphenyl in aqueous solution using palladized nickel foam cathode

The electrocatalytic hydrodechlorination of 4-chlorobiphenyl on palladized nickel foam with high porous structure in an aqueous solution containing MeOH, bromide of hexadecyltrimethylammonium (CTAB), sodium acetate, and acetic acid were investigated in a membrane-separated flow-through cell. The Pd/Ni foam electrode was prepared by electroless deposition method, on which the Pd particles dispersed finely over Ni foam surface indicated by SEM-EDX analysis. The effects of current density, organic cosolvent, initial concentration, temperature, and flow rate on the hydrodechlorination of 4-chlorobiphenyl were examined. Methanol was among the best cosolvents and was used in preferential concentration of 50 vol%. Moderate current density (e.g., 2.23 mA cm(-2)), relatively high initial concentration, temperature, and flow rate were beneficial to improve the hydrodechlorination of 4-chlorobiphenyl. The current efficiencies for the conversion of 1mM 4-MCB decreased with increasing current density and range from 37.2% at 0.74 mA cm(-2) to 14.1% at 5.21 mA cm(-2) after 20 min electrolysis cut. Under the optimized conditions, 1mM of 4-MCB could be removed rapidly with the rate of 94.6% after 2h electrolysis, which gave current efficiencies and energy consumptions in range of 8.1-24.6% and 1.7-5.2 kW h kg(-1), respectively.     

Development of the DGT technique for Hg measurement in water: comparison of three different types of samplers in laboratory assays

The Diffusive Gradients in Thin films (DGT) technique is an operationally defined method to determine the dissolved fraction of trace elements in water. The aim of this study was to develop this technique for the measurement of the bioavailable mercury species in natural waters. For that purpose, three types of DGT units (commercial, manufactured with agarose diffusive gel (DG) and manufactured with polyacrylamide DG) were tested under controlled conditions using an Hg(II) solution both with and without dissolved organic matter (DOM). An acid digestion method using aqua regia was optimised to efficiently digest the resin gel discs prior to analysis. A good performance was obtained for the three DGT types when deployed in a DOM-free mercury solution in the laboratory, and it was demonstrated that polyacrylamide gel can be used as diffusive layer for mercury sampling. However, when the DGT units were deployed in a mercury solution containing DOM, performance differences were observed. Furthermore, the mass of background mercury (blanks) varied among the different DGT types. In the light of the results, the devices manufactured with polyacrylamide DG seemed to be the best choice for dissolved mercury determination.     

投加ABS颗粒对MBR膜过滤特性的影响

向膜生物反应器(MBR)中投加ABS颗粒,以干扰膜表面泥饼层的形成和减轻膜污染的发生。结果表明,向MBR中投加粒径为1 mm的ABS颗粒,发现颗粒的最佳投加量为1.5 kg/m3,投加颗粒的膜运行时间是对照实验运行时间的3倍。颗粒对膜表面泥饼沉积层抑制明显,与对照实验泥饼层重量最大相差290 g,颗粒使膜上泥饼层的分布也不同。颗粒的投加也改变了污泥EPS含量,相比对照实验,多糖、蛋白质含量分别提高了17.2%和8%,污泥粘度提高了17.6%。细格栅与颗粒使MBR对TN、TP去除效果分别提高了8.5%和9.7%,对COD的影响不大。     

The size distribution of polychlorinated dibenzo-p-dioxins and dibenzofurans in the bottom ash of municipal solid waste incinerators

In this study, bottom ash was sampled from two Taiwanese municipal solid waste incinerators (MSWIs: A and B) and sieved to size classes of 4.75-9.5 mm, 2.36-4.75 mm, 1.0-2.36 mm, 0.6-1.0 mm, 0.3-0.6 mm, 0.21-0.3 mm, 0.125-0.21 mm, 0.075-0.125 mm and <0.074 mm. For both MSWIs, the major peak in the particle size distribution for the PCDD/F content was found in a particle size <0.21 mm, that is, 16.1 (A) and 4.37 pg I-TEQ/g (B). This is due to the fact that a smaller particle has higher specific surface area thus offering more adsorption sites. The mean cumulative fractions (F%) of PCDD/F I-TEQ in the bottom ash of MSWI A and B in the particle size range below 0.6, 2.36 and 4.75 mm, in sequence, are 40.4%, 77.2% and 95.6%, respectively. We suggest sieving the bottom ash before the subsequent reutilization at the suggested cut size of 0.6 mm. In the view of PCDD/Fs, bottom ash with a particle size larger than 0.6 mm, which is the more non-hazardous part, may be suitable for being the raw material of landfilling soil, road sub-base, and construction blocks. For the minus 0.6 mm fraction, vitrification with fly ash is one of the choices.     

The study on biomass fraction estimate methodology of municipal solid waste incinerator in Korea

In Korea, the amount of greenhouse gases released due to waste materials was 14,800,000 t CO₂eq in 2012, which increased from 5,000,000 t CO₂eq in 2010. This included the amount released due to incineration, which has gradually increased since 2010. Incineration was found to be the biggest contributor to greenhouse gases, with 7,400,000 t CO₂eq released in 2012. Therefore, with regards to the trading of greenhouse gases emissions initiated in 2015 and the writing of the national inventory report, it is important to increase the reliability of the measurements related to the incineration of waste materials.

This research explored methods for estimating the biomass fraction at Korean MSW incinerator facilities and compared the biomass fractions obtained with the different biomass fraction estimation methods. The biomass fraction was estimated by the method using default values of fossil carbon fraction suggested by IPCC, the method using the solid waste composition, and the method using incinerator flue gas.

The highest biomass fractions in Korean municipal solid waste incinerator facilities were estimated by the IPCC Default method, followed by the MSW analysis method and the Flue gas analysis method. Therefore, the difference in the biomass fraction estimate was the greatest between the IPCC Default and the Flue gas analysis methods. The difference between the MSW analysis and the flue gas analysis methods was smaller than the difference with IPCC Default method. This suggested that the use of the IPCC default method cannot reflect the characteristics of Korean waste incinerator facilities and Korean MSW.

Implications: Incineration is one of most effective methods for disposal of municipal solid waste (MSW). This paper investigates the applicability of using biomass content to estimate the amount of CO₂ released, and compares the biomass contents determined by different methods in order to establish a method for estimating biomass in the MSW incinerator facilities of Korea. After analyzing the biomass contents of the collected solid waste samples and the flue gas samples, the results were compared with the Intergovernmental Panel on Climate Change (IPCC) method, and it seems that to calculate the biomass fraction it is better to use the flue gas analysis method than the IPCC method. It is valuable to design and operate a real new incineration power plant, especially for the estimation of greenhouse gas emissions.     

Design, manufacture and testing of a waste paper recycling system

Egypt is facing a major crisis due to the 1997's 40% increase in the price of imported newsprint. This price increase not only affected the press and publishers, but also placed a burden on the educational system, because most of the government textbooks depend on this type of imported paper. This crisis can be solved entirely by recycling waste paper and depending on recycled paper instead of imported paper. An experimental test facility for paper recycling was designed, manufactured and tested at the American University in Cairo (AUC). The system consists of a shredder, a beater to produce pulp, a flotation cell to remove the ink mechanically, a hand-sheet machine to produce test paper and a press/dryer to dry the paper. The paper produced was tested for physical (tear and tension) and optical (brightness and opacity) properties at different times and temperatures. The system proved to be very efficient.     

An Analysis of Visual Range in the Eastern United States Under Different Meteorological Regimes

ABSTRACT

The issue of fine particle (PM₂₅) exposures and their potential health effects is a focus of scientific research because of the recently promulgated National Ambient Air Quality Standard for PM_{2 5}. Before final implementation, the health and exposure basis for the standard will be reviewed by the U.S. Environmental Protection Agency within the next five years. As part of this process, it is necessary to understand total particle exposure issues and to determine the relative importance of the origin of PM_{2 5} exposure in various micro-environments. The results presented in this study examine emissions of fine particles from a previously uncharacterized indoor source: the residential vacuum cleaner. Eleven standard vacuum cleaners were tested for the emission rate of fine particles by their individual motors and for their efficiency in collecting laboratory-generated fine particles. An aerosol generator was used to introduce fine potassium chloride (KC1) particles into the vacuum cleaner inlet for the collection efficiency tests. Measurements of the motor emissions, which include carbon, and the KCl aerosol were made using a continuous HIAC/Royco 5130A light-scattering particle detector. All tests were conducted in a metal chamber specifically designed to completely contain the vacuum cleaner and operate it in a stationary position. For the tested vacuum cleaners, fine particle motor emissions ranged from 9.6 x 10⁴ to 3.34 x 10⁸ particles/min, which were estimated to be 0.028 to 176 mg/min for mass emissions, respectively. The vast majority of particles released were in the range of 0.3-0.5 mm in diameter. The lowest particle emission rate was obtained for a vacuum cleaner that had a high efficiency (HEPA) filter placed after the vacuum cleaner bag and the motor within a sealed exhaust system. This vacuum cleaner removed the KC1particles that escaped the vacuum cleaner bag and the particles emitted by the motor. Results obtained for the KC1 collection efficiency tests show >99% of the fine particles were captured by the two vacuum cleaners that used a HEPA filter. A series of tests conducted on two vacuum cleaners found that the motors also emitted ultra-fine particles above 0.01 mm in diameter at rates of greater than 10⁸ ultra-fine particles/CF of air. The model that had the best collection efficiency for fine particles also reduced the ultra-fine particle emissions by a factor of 1 x 10³.     

Seasonal characteristics of chemically apportioned aerosol optical properties at Seoul and Gosan,Korea

Seasonal variations of aerosol optical properties in Seoul (polluted urban site) and Gosan (coastal background site), Korea, with an emphasis on the relative humidity were investigated using ground-based aerosol measurements and optical model calculations. The mass fraction of elemental carbon was 9–20%, but the optical contribution of these particles to light extinction was higher, up to 33–55% in Seoul. In Gosan, the contribution of non-sea-salt water-soluble aerosols on extinction was 81–93% due to the high mass fraction of these particles. Based on daily MODIS datasets, our analysis showed that the aerosol optical depths at Seoul and Gosan were highest in spring due to the influence of dust particles. The aerosol water content at Gosan, calculated using a thermodynamic equilibrium model, was higher than that at Seoul; this was attributed to the high relative humidity and high fraction of water-soluble aerosols at Gosan. At Seoul, despite abundant water vapors in summer, the possibility of hygroscopic growth of water-soluble aerosols was not more significant than that at Gosan.     

高稳定性污泥蛋白发泡剂的发泡特性及应用研究

以污泥蛋白为实验材料，通过加入不同量的稳定剂GP-1，配制成高稳定性污泥蛋白发泡剂，并对高稳定性污泥蛋白发泡剂的发泡特性和影响因素进行研究。结果表明，以污泥蛋白10 mL、水90 mL、GP-1 0.4 g配方组合为研究对象，所制备的泡沫初始体积为770 mL，泡沫泌水时间大于15 h，泡沫半衰期大于64 h，泡沫综合发泡能力为2.2×10⁶ mL·min，泡沫的最佳搅拌时间为5 min，泡沫的泌水时间和泡沫的半衰期都是随着温度的上升而下降，在pH为3～13时泡沫稳定。经过对高稳定性污泥蛋白发泡剂发泡特性研究以及对水泥的胶凝时间、特性进行比较，研制出污泥蛋白泡沫混凝土发泡剂，并制备污泥蛋白泡沫混凝土块；结果表明，当污泥蛋白泡沫混凝土发泡剂的用量分别为0、6、6.8、7.6、8.4和9.2 mL，水泥为200 g时，制备泡沫混凝土块，其密度由2.07 g/cm³下降到0.34 g/cm³，体积由130 cm³ 上升到755 cm³；在泡沫混凝土块脱模后的第1 d、第7 d、第28 d分别称量他们的重量变化情况，结果表明，泡沫混凝土块第1 d和第7 d无重量变化，第28 d的重量明显减轻。该研究为污泥蛋白研制成为泡沫混凝土发泡剂，并应用于屋面隔热、保温建立前期基础。