回转窑式纯氧熔融焚烧垃圾技术研究

生活垃圾安全无害化处理是目前迫切需要解决的问题,直接气化熔融焚烧垃圾技术以降低二恶英排放方面巨大优势得到广泛关注,在此基础上提出纯氧熔融焚烧垃圾技术,几乎可以实现所有二次污染物近零排放。以350 t/d回转窑垃圾焚烧炉为例,对纯氧代替空气应用在回转窑上熔融焚烧垃圾系统进行了详细热力计算及分析。结果表明,纯氧熔融焚烧垃圾系统的锅炉效率可达90.56%,回转窑熔融焚烧系统还可以在垃圾焚烧后灰渣达到熔融温度的条件下,保持该系统热量平衡,稳定燃烧。并参考回转窑设计标准对该纯氧熔融焚烧城市生活垃圾的回转窑参数进行确定。     

不同级配垃圾焚烧底渣固化市政污泥工程特性分析

开展了(炉排炉和流化床炉)两种垃圾焚烧底渣与固化剂共同作用下固化市政污泥的工程特性研究。分析了两种底渣化学成份及物理级配上的差异,重点考察了在密封养护情况下,测定了不同底渣固化体的含水率、pH值、无侧限抗压强度及28d渗透系数等工程特性指标。研究结果表明:相同含量的两种底渣固化体含水率及pH相同,且含水率随底渣含量增加而降低,而pH值随底渣含量增加而增加;随着底渣含量增加,级配良好的炉排炉底渣固化体强度比级配不良的流化床底渣固化体强度从高8 k Pa增加到30 k Pa;受底渣级配的影响,炉排炉底渣固化体渗透系数随底渣含量增加而增大,而流化床底渣固化体渗透系数基本不变。级配良好的炉排炉底渣固化体工程特性优于级配不良的流化床底渣固化体,具有更强的骨架作用。研究成果为污泥及垃圾焚烧底渣填埋处置提供了科学借鉴。     

垃圾焚烧烟气净化技术探讨及实践

焚烧城市固体垃圾所产生的烟气是一种含有有机化合物和无机化合物的复杂混合物。文章分析了垃圾焚烧烟气的产生与特性 ,探讨了一些典型垃圾焚烧厂的烟气净化方法 ,比选推荐了垃圾焚烧烟气净化的主工艺 ,以确保焚烧后烟气排放降低到最低水平 ,满足日趋严格的环保排放标准。介绍了生活垃圾焚烧厂烟气净化处理的最新实例     

城市生活垃圾并流竖炉焚烧模拟实验研究

气化熔融焚烧技术能够避免重金属和二恶英的二次污染，被公认为实现零排放和环境友好型的焚烧方法。在这样的背景下提出了生活垃圾并流竖炉气化熔融焚烧工艺。该工艺以竖炉为气化熔融主体设备，垃圾料层与助燃空气在炉内都是至上而下并流流动，从而使垃圾热解气化产生的可燃气体在竖炉下部完全燃烧，以提供灰渣熔融耗热。并流竖炉热态模拟试验表明，并流时垃圾料层中各点的温度明显高于逆流情况，并流时产生的CO₂量明显高于逆流情况。因此说并流竖炉更适合气化熔融焚烧工艺的要求。     

城市生活垃圾在机械炉排炉内焚烧过程研究及数值模拟

研究城市生活垃圾在机械炉排炉内焚烧过程，建立了垃圾在炉排炉移动床内燃烧过程中垃圾体积变化、水分蒸发、挥发分析出及燃烧、垃圾颗粒的移动、气-固两相热传递、焦炭燃烧等各个反应阶段的热化学模型，采用一维非稳态模型分别建立了床层内气固两相介质控制方程。通过对炉排上垃圾焚烧过程的数值模拟研究，获得料层中温度分布、料层高度、炉床机械负荷、气相中反应物组分和污染物浓度分布。利用建立的模型对某大型垃圾焚烧炉的燃烧过程进行数值仿真，对燃烧过程、烟气成分进行预测，为垃圾焚烧炉排炉的设计和燃烧控制提供理论依据。     

150t/d循环流化床生活垃圾焚烧炉的工艺结构与污染排放

垃圾焚烧处理技术在我国的应用越来越广泛 ,单纯引进国外的垃圾焚烧处理技术已经无法满足我国经济发展的需要。清华大学自主开发研制的 15 0t/d循环流化床生活垃圾焚烧炉已经通过专家鉴定 ,各项焚烧污染物排放指标均达到或优于国家标准 ,总体水平居国内领先水平。本文详细介绍了该焚烧炉的系统及结构 ,并对有关控制污染物排放的技术手段进行了详细分析     

采用循环流化床技术焚烧城市生活垃圾

根据目前我国城市生活垃圾热值偏低的实际情况 ,提出以煤为辅助燃料 ,采用循环流化床焚烧技术处理生活垃圾 ,可大幅度降低运行成本 ,符合国情。阐述了循环流化床焚烧技术在降低NOx、SO2 和二噁等方面的优越性。尾气处理建议采用喷活性碳 +布袋除尘组合工艺 ,飞灰处理建议采用高温熔融处理     

采用循环流化床技术焚烧城市生活垃圾

根据目前我国城市生活垃圾热值偏低的实际情况，提出以煤为辅助燃料，采用循环流化床焚烧技术处理生活垃圾，可大幅度降低运行成本，符合国情。阐述了循环流化床焚烧技术在降低NOx、SO2和二噁英等方面的优越性。尾气处理建议采用喷活性碳 布袋除尘组合工艺，飞灰处理建议采用高温熔融处理。     

两种典型垃圾焚烧灰渣特性的试验研究

针对垃圾的炉排型和流化床型两种典型焚烧工艺,取焚烧底渣和焚烧飞灰样品若干,进行了样品的能谱分析(EDX)和X射线衍射(XRD)分析,并进行对比.研究结果表明,两种焚烧工艺产生的焚烧底渣元素组成均以C、O、Ca为主,而焚烧飞灰相对于焚烧底渣具有结构复杂和性质多变的特性.炉排型焚烧飞灰比流化床型焚烧飞灰含有更多的重金属,更具危险性.     

150t／d循环流化床生活垃圾焚烧炉的工艺结构与污染排放

垃圾焚烧处理技术在我国的应用越来越广泛，单纯引进国外的垃圾焚烧处理技术已经无法满足我国经济发展的需要。清华大学自主开发研制的150t／d循环流化床生活垃圾焚烧炉已经通过专家鉴定，各项焚烧污染物徘放指标均达到或优于国家标准，总体水平居国内领先水平。本文详细介绍了该焚烧炉的系统及结构，并对有关控制污染物排放的技术手段进行了详细分析。     

Chloroaromatic pollutants in mussels incubated in two finnish watercourses polluted by industry

Concentrations of different chlorinated compounds were measured in mussels incubated in two polluted watercourses, a river (the River Kymijoki) and a lake (Lake Vanaja) for four weeks in summer 1995. The sum concentrations of polychlorinated phenols (PCP) and biphenyls (PCB) were both about 1 μg/g lipid weight (lw) in Lake Vanaja mussels, while in the River Kymijoki mussels PCPs were non-detectable and PCBs were measured 120 ng/g lIw. The concentrations of toxic polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) congeners ranged between <17 and 370 pg/g Iw in Lake Vanaja mussels and between <38 and 11,000 pg/g lw in the River Kymijoki mussels. Polychlorinated diphenyl ethers (PCDE) were detected in the mussels incubated in the River Kymijoki (0.4–1.1 ng/g Iw), but not in those incubated in Lake Vanaja. Polychlorinated phenoxyanisoles (PCPA) were measured 33 ng/g lw and polychlorinated phenoxyphenols (PCPP) 300 ng/g lw in the mussels incubated in the River Kymijoki. PCPAs were also detected in reference samples, which were sediment and pike from the River Kymijoki and Baltic salmon, seal and white-tailed sea eagle.     

Book review

The Pesticide Manual ‐ A World Compendium, 8th Edition, C.R. Worthing, Editor and S.B. Walker, Assistant Editor, British Crop Protection Council, BCPC Publications Sales, Bear Farm, Binfield, Bracknell, Berkshire RG12 5QE, England. 1987, 1100 pp., UK £50; Overseas £56. ISBN 0–948404–01–9.     

Patterns of volatile metabolites and nonvolatile trichothecenes produced by isolates of <Emphasis Type="Italic">Stachybotrys,Fusarium, Trichoderma,Trichothecium</Emphasis> and <Emphasis Type="Italic">Memnoniella</Emphasis>

We reported previously that trichodiene, a volatile trichothecene derivative, was produced by a Stachybotrys isolate, also known to produce highly cytotoxic, non-volatile, macrocyclic trichothecenes (satrotoxins). We investigated the relationship between the production of trichodiene and various non-volatile trichothecenes for several molds. Volatile metabolites were concentrated by adsorption on Tenax TA and analyzed by GC/MS, while non-volatile metabolites were separated by HPLC, derivatized and analyzed by GC/MS. Stachybotrys chartarum isolates producing macrocyclic trichothecenes secreted significantly larger amounts of trichodiene and other sesquiterpenes than isolates which only produced simple trichothecenes. The amounts of secreted trichodiene were relatively small in all cases. With the exception of Memnoniella, which excreted small amounts of sesquiterpenes, the other isolates produced varying amounts of sesquiterpenes, including trichodiene, as well as simple tricothecenes, no detectable trichodiene, but large amounts of griseofulvin derivatives. In Stachybotrys there is apparently a correlation between trichodiene and macrocyclic trichothecene production. In the remaining isolates, there was no simple relationship between trichodiene and non-volatile trichothecene synthesis. Trichodiene is produced in larger amounts by Stachybotrys isolates, which also produce satratoxins, but it will be difficult to utilize this metabolite to detect toxic isolates in buildings due to the relatively small amounts excreted.     

The chemical stability of formulations of some hydrolyzable insecticides in aqueous mixtures with hydrolysis catalysts

Abstract

The active ingredients in commercial formulations of malathion, oxamyl, carbaryl, diazinon, and chlorpyrifos diluted to “spray tank”; concentrations with buffered distilled or natural water of pH 4–9 were stable for at least 24 hr. Formulations of trichlorfon were not stable at pH 7 or above but disappearance rates were slower than for the pure chemical in homogeneous solution. Cupric ion was observed to be an effective catalyst for the hydrolysis of a variety of pure organophosphorus insecticides but did not catalyze hydrolysis of the active ingredients of the formulations examined. Increasing the dilution of the formulation increased the susceptibility of malathion, oxamyl, and carbaryl to hydrolysis.     

Organochlorine compounds in a three-step terrestrial food chain

The concentrations of 15 organochlorine chemicals (PCBs and pesticides) were studied in a Central European oak wood food chain system: Great tit (Parus major), caterpillars (Tortrix viridana, Operophtera brumata, Erannis defoliaria), and oak-leaves (Quercus robur). Juvenile tits receive organochlorines from the mother via egg transfer and, eventually to a greater extent, from the caterpillar food source during nestling period. The concentrations of PCB 153 (2,2′,4,4′,5,5′-hexachlorobiphenyl, the most abundant in this study) was found in leaf material at ca. 1 ng/g, in caterpillars 10 ng/g, and in bird eggs 170 ng/g on an average and on a dry mass basis.     

Radionuclides and trace elements in fish collected upstream and downstream of Los Alamos national laboratory and the doses to humans from the consumption of muscle and bone

Abstract

The purpose of this study was to determine radionuclide and trace element concentrations in bottom‐feeding fish (catfish, carp, and suckers) collected from the confluences of some of the major canyons that cross Los Alamos National Laboratory (LANL) lands with the Rio Grande (RG) and the potential radiological doses from the ingestion of these fish. Samples of muscle and bone (and viscera in some cases) were analyzed for ³H, ⁹⁰Sr, ¹³⁷Cs, ^totU, ²³⁸Pu, ^239,240Pu, and ²⁴¹Am and Ag, As, Ba, Be, Cr, Cd, Cu, Hg, Ni, Pb, Sb, Se, and Tl. Most radionuclides, with the exception of ⁹⁰Sr, in the muscle plus bone portions of fish collected from LANL canyons/RG were not significantly (p<0.05) higher from fish collected upstream (San Ildefonso/background) of LANL. Strontium‐90 in fish muscle plus bone tissue significantly (p<0.05) increases in concentration starting from Los Alamos Canyon, the most upstream confluence (fish contained 3.4E‐02 pCi g^‐1 [126E‐02 Bq kg^‐1]), to Frijoles Canyon, the most downstream confluence (fish contained 14E‐02 pCi g^‐1 [518E‐02 Bq kg^‐1]). The differences in ⁹⁰Sr concentrations in fish collected downstream and upstream (background) of LANL, however, were very small. Based on the average concentrations (±2SD) of radionuclides in fish tissue from the four LANL confluences, the committed effective dose equivalent from the ingestion of 46 lb (21 kg) (maximum ingestion rate per person per year) of fish muscle plus bone, after the subtraction of background, was 0.1 ± 0.1 mrem y^‐1 (1.0 ± 1.0 μSv y^‐1), and was far below the International Commission on Radiological Protection (all pathway) permissible dose limit of 100 mrem y^‐1 (1000 μSv y^‐1). Of the trace elements that were found above the limits of detection (Ba, Cu, and Hg) in fish muscle collected from the confluences of canyons that cross LANL and the RG, none were in significantly higher (p<0.05) concentrations than in muscle of fish collected from background locations.     

Radionuclides in pinon pine (Pinus edulis) nuts from los alamos national laboratory lands and the dose from consumption

Abstract

One of the dominant tree species growing within and around the eastern portion of Los Alamos National Laboratory (LANL), Los Alamos, NM, lands is the pinon pine (Pinus edulis). Pinon pine is used for firewood, fence posts, and building materials and is a source of nuts for food—the seeds are consumed by a wide variety of animals and are also gathered by people in the area and eaten raw or roasted. This study investigated the (1) concentration of ³H, ¹³⁷Cs, ⁹⁰Sr, ^totU, ²³⁸Pu, ^{239, 240}Pu, and²⁴¹ Am in soils (0‐ to 12‐in. [31 cm] depth underneath the tree), pinon pine shoots (PPS), and pinon pine nuts (PPN) collected from LANL lands and regional background (BG) locations, (2) committed effective dose equivalent (CEDE) from the ingestion of nuts, and (3) soil to PPS to PPN concentration ratios (CRs). Most radionuclides, with the exception of ³H in soils, were not significantly higher (p < 0.10) in soils, PPS, and PPN collected from LANL as compared to BG locations, and concentrations of most radionuclides in PPN from LANL have decreased over time. The maximum net CEDE (the CEDE plus two sigma minus BG) at the most conservative ingestion rate (10 lb [4.5 kg]) was 0.0018 mrem (0.018 μSv); this is far below the International Commission on Radiological Protection (all pathway) permissible dose limit of 100 mrem (1000 μSv). Soil‐to‐nut CRs for most radionuclides were within the range of default values in the literature for common fruits and vegetables.     

Degradation and sorption of imidacloprid in dissimilar surface and subsurface soils

Degradation and sorption/desorption are important processes affecting the leaching of pesticides through soil. This research characterized the degradation and sorption of imidacloprid (1-[(6-chloro-3-pyridinyl)-methyl]-N-nitro-2-imidazolidinimine) in Drummer (silty clay loam) and Exeter (sandy loam) surface soils and their corresponding subsurface soils using sequential extraction methods over 400 days. By the end of the incubation, approximately 55% of imidacloprid applied at a rate of 1.0 mg kg^?1 degraded in the Exeter sandy loam surface and subsurface soils, compared to 40% of applied imidacloprid within 300 days in Drummer surface and subsurface soils. At the 0.1 mg kg^?1 application rate, dissipation was slower for all four soils. Water-extractable imidacloprid in Exeter surface soil decreased from 98% of applied at day 1 to > 70% of the imidacloprid remaining after 400 d, as compared to 55% in the Drummer surface soil at day 1 and 12% at day 400. These data suggest that imidacloprid was bioavailable to degrading soil microorganisms and sorption/desorption was not the limiting factor for biodegradation. In subsurface soils > 40% of ¹⁴C-benzoic acid was mineralized over 21 days, demonstrating an active microbial community. In contrast, cumulative ¹⁴CO₂ was less than 1.5% of applied ¹⁴C-imidacloprid in all soils over 400 d. Qualitative differences in the microbial communities appear to limit the degradation of imidacloprid in the subsurface soils.     

Biochemical interaction of six op delayed neurotoxicants with several neurotargets

Abstract

Five organophosphorous insecticides: Leptophos, EPN, Cyano‐fenphos, trichloronate and salithion proved to cause irreversible ataxia not only to chicken but also to mice and sheep. TOCP was included as a reference. Cyanofenphos blocked the catecholamine B‐receptor binding activity with ³H‐norepinephrine at a level similar to that of the specific inhibitor propranolol in the mouse heart preparation. In the lamb heart preparation, the B‐receptor was more sensitive to Leptophos, salithion and TOCP than to propranolol. The six compounds and their oxons were screened for their in‐vitro inhibition to monamine oxidase (MAO), acetyl cholinesterase (AChE) and neurotoxic esterase (NTE) in the brain of either mouse, lamb or chicken. It is believed that their AChE inhibition stands for their acute toxicity, while NTE inhibition is responsible for their paralytic ataxia.