煤粉炉掺烧干化污泥的污染物排放研究

结合某电厂420 t/h四角煤粉炉掺烧污泥项目的实验室分析测试,了解煤粉掺烧不同含水率不同比例的干化污泥条件下烟气中污染物和灰渣中重金属的排放特性。结果表明,在实验研究配比和燃烧的条件下,大部分重金属元素Pb、Cu、Cr和Ni残留在灰渣中,Zn、Cd部分残留在灰渣中,As、Hg和Se等易挥发元素释放到烟气中,在灰渣中的含量很小。掺烧污泥后,灰渣中的重金属含量较单烧单煤都有了一定幅度的升高,Zn的含量是单煤的2倍,其余重金属是单煤的1.1~1.2倍。3种不同的掺混比例之间的污染气体排放浓度基本相似。烟气中主要污染物及重金属浓度可以满足现行国家标准。与单烧单煤相比,CO、HCl以及其他有机气体排放浓度基本相同;NH3的排放浓度较单煤有所升高;SO2、NOx和CO2排放浓度略有降低;飞灰浓度有所升高。烟气中的重金属,Hg含量升高了30%,Pb含量约为单煤的4.3~4.8倍。以上研究结果可为环保达标和飞灰利用提供基础数据。     

水泥旋窑并行处理城市污水厂污泥的污染物排放研究

通过重庆某水泥厂的工业试验，测定了水泥旋窑并行处理城市污水厂污泥的烟气参数及污染物排放指标，分析了并行处理污泥对旋窑烟气的影响程度及各项指标之间的相关性。结果表明：①在污泥添加速率增大时，烟气流速、排气量、含氧量、空气过剩系数、HF和SO₂等排放浓度均随之增加，粉尘、NO_x排放浓度基本保持不变，HCl排放浓度下降，CO排放浓度先剧增后缓慢下降，而总烃排放浓度无明显规律；②污泥添加速率与SO₂排放浓度、烟气流速与排气量、含氧量与空气过剩系数、总烃浓度与SO₂排放浓度、烟气流速与总烃浓度呈显著正相关，污泥添加速率与HCl浓度、SO₂浓度与HCl浓度、NO_x与总烃浓度呈显著负相关；③烟气排放的污染物主要来自煤的燃烧，各指标之间的相关性主要表现为煤耗量增加而引起的连锁效应，但污泥本身在高温条件下燃烧产生的污染物较少，由污泥燃烧产生的污染物之间的相关性较小；④污泥添加速率达到2.4 t/h时，水泥旋窑并行处理城市污水处理厂污泥过程中所有指标均满足国家及相应的控制标准，但其参数优化及污染物控制极为复杂，该方法处理污泥需要进行深入研究才能在工业上应用。     

火电厂协同资源化处理城市污泥二次污染控制

控制循环流化床锅炉掺烧城市污泥二次污染物的排放,实现污泥的减量化、无害化处置和资源化利用。方法:利用循环流化床锅炉烟气余热干燥污泥,干化污泥与燃煤掺配燃烧,污泥干燥系统与锅炉DCS控制系统对接,依据机组负荷自动化控制锅炉耗煤量、床温和污泥给入量等运行参数,有效抑制二恶英的形成。结果表明,污泥自动化掺烧系统投运后,烟气中二恶英的排放浓度小时均值不高于0.011 0 ng TEQ·(Nm)-3,飞灰中二恶英含量不高于2.802 2 ng TEQ·kg-1、底渣中二恶英含量不高于0.659 6 ng TEQ·kg-1,符合国家污染控制标准要求。火电厂协同资源化处理城市污泥过程中,污泥自动化掺烧系统投运能够有效控制二次污染物的排放,实现了城市污泥的减量化、无害化处置和资源化利用。     

基于Aspen Plus软件的生物质气与煤混合燃烧烟气排放特性计算分析

为了分析生物质气与煤混合燃烧对烟气排放特性的影响,基于Aspen Plus软件,搭建了生物质气与煤混合燃烧模型,对混合燃烧产物进行模拟计算。在生物质气化过程中,随着空燃比的增加,生物质气的低位热值先升高后降低。选取低位热值最高时的生物质气和煤在不同生物质掺烧比例下混合燃烧。随着生物质掺烧比例从0%增加到30%,在保证混合燃烧的理论空气量条件下,炉膛燃烧温度逐渐下降,烟气排放特性也随之变化。在掺烧比例达到30%时,SO_2的体积分数降低了30%左右,H_2O的体积分数增加了26.7%~39.2%,烟气排放量增加了2.38%~3.2%。随着生物质掺烧比例的增加,混合燃烧对锅炉运行造成的影响逐渐增大。     

市政污泥与生活垃圾混烧技术验证

对市政污泥与生活垃圾混烧进行了验证研究。结果表明，与生活垃圾单独焚烧相比，污泥与生活垃圾混烧后烟气中NOx、CO和HCl的浓度没有出现明显变化，而SO2浓度出现了下降（从82～93mg／m3下降至41～70mg／m3）；Hg、Pb、Sn、Cr和Zn的浓度均表现为不同程度的上升，但仍然符合GB[g485；二恶英从0．0087μgTEQ／m3降至O．0047μgTEQ／m3。掺烧半干污泥比例为10％、12％和15％时，吨物质的发电量分别为311．8kWh／t、306．7kWh／t和296．1kwh／t。混烧污泥在一定程度上降低了系统的发电量，因此建议混烧污泥的比例不应大于15％。测算的污泥混烧成本约209元／t（80％含水率）。     

循环流化床垃圾焚烧炉助燃配风改造对降低CO排放效果的数值模拟

循环流化床(CFB)是垃圾焚烧主要炉型之一,中国生活垃圾具有水分高和挥发分高等特性导致现阶段CFB垃圾焚烧炉CO排放偏高,对其正常运转造成较大影响。对锅炉实体进行助燃配风改造,结合计算流体动力学技术对改造前后炉膛流体场进行模拟,并分析第一烟道内的流场分布情况。结果表明:助燃配风率为40%时,CO的排放均值可降低至80mg/Nm3,烟气含氧量保持在9.5%(体积分数)左右,炉膛中上部温度的平均增幅达到41.3℃。可视化数值模拟结果表明,助燃配风明显提高了烟气旋流和回流,使得烟气轴向速度降幅达37.69%,烟气在第一烟道内停留时间延长;改造后炉膛中上部局部区域内的颗粒质量浓度均值在2.287kg/m3左右,优化了助燃配风参与炉内燃烧的能力。     

水泥窑协同处置危险废物的烟气污染物排放特性研究

水泥窑协同处置技术能够有效地缓解危险废物(以下简称危废)的处置压力,是一项很有发展前景的危废处置技术。通过监测两座典型的新型干法水泥窑在协同处置危废时窑尾烟气中烟尘、SO2和NOx等污染物的排放浓度,评价两条水泥生产线在协同处置危废时污染物排放浓度能否达标。监测结果表明,水泥窑协同处置危废时烟气污染物浓度均低于《水泥工业大气污染物排放标准》(GB 4915—2013)和《水泥窑协同处置固体废物污染控制标准》(GB 30485—2013)规定的排放限值。同时,两座水泥窑烟气中烟尘、SO2、NOx和HF等污染物的排放因子均低于我国新型干法水泥窑污染物排放的平均值,表明两条水泥生产线窑尾烟气净化系统运行良好。此外,还研究了水泥窑协同处置危废前后二噁英排放毒性当量浓度的变化情况。     

混合燃料中含氧量对柴油机有害物质排放量的影响

通过柴油机试验,研究了混合燃料中含氧量对柴油机有害物质排放量的影响.试验结果显示,在混合燃料中含氧量低于10.4%(质量分数,下同)时,CO和HC排放量随含氧量增加而减少;但随着混合燃料中乙醇所占比例增加,当混合燃料中含氧量达25.3%时,CO和HC排放量均增加到含氧量为10.4%时的2.5倍左右;当混合燃料中含氧量低于10.4%时,NOx排放量随其增加而少量增加.但当混合燃料中含氧量达25.3%时,NOx排放量较燃用柴油时减少50%以上;碳烟排放量则随着混合燃料中含氧量增加而不断减少.     

低温环境中乙醇汽油和普通汽油的冷凝水与污染物排放

对低温环境中乙醇汽油和普通汽油的冷凝水、CO、HC、NOx和CO2排放特性进行了研究,并对5种排放物的形成机理和排放趋势进行了分析。ECE工况(-20、-10和0℃)和怠速工况(-30、-20、-10和0℃)下,乙醇汽油和普通汽油的冷凝水排放量主要受含氢量、车辆构造和外界环境的共同影响。ECE工况中冷凝水的总体排放趋势是随着温度降低而增加,乙醇汽油的总排水量持平或略低于普通汽油。-10℃时乙醇汽油的高含氧量能促进燃烧速度和燃烧效率,减少CO和HC排放,增加NOx排放;0℃时低温环境和乙醇的高汽化潜热会影响可燃混合气形成和燃烧速度,降低缸壁温度,增加CO和HC排放。     

城市污水厂石灰干化污泥对水泥易烧性的影响

针对城市污水处理厂污泥含水率高、体积大、泥质成分复杂且易造成二次污染的特点,采用石灰干化后利用水泥工业协同处置是其实现资源化的途径之一。实验结果表明,在煅烧温度1 400℃、保温时间60 min的条件下,掺加适量的石灰干化污泥有利于提高水泥生料的易烧性,熟料中f-Ca O含量符合国家标准;掺加质量比为12%的石灰干化污泥煅烧所得熟料与空白参比熟料的物相组成基本相同,当石灰干化污泥掺量过大时应根据泥质成分对生料配比进行相应的调整,以确保熟料达到水泥生产的质量要求。研究成果可为水泥工业协同处置城市污泥提供借鉴与技术参考。     

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.     

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.     

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 in deer and elk from Los Alamos national laboratory and the doses to humans from the ingestion of muscle and bone

Abstract

This paper summarizes radionuclide concentrations (³H, ⁹⁰Sr, ¹³⁷Cs, ²³⁸Pu, ^239,240Pu, ²⁴¹Am, and ^totU) in muscle and bone tissue of mule deer (Odocoileus hemionus) and Rocky Mountain elk (Cervus elaphus) collected from Los Alamos National Laboratory (LANL), Los Alamos, New Mexico, lands from 1991 through 1998. Also, the committed effective dose equivalent (CEDE) and the risk of excess cancer fatalities (RECF) to people who ingest muscle and bone from deer and elk collected from LANL lands were estimated. Most radionuclide concentrations in muscle and bone from individual deer (n = 11) and elk (n = 22) collected from LANL lands were either at less than detectable quantities (where the analytical result was smaller than two counting uncertainties) and/or within upper (95%) level background (BG) concentrations. As a group, most radionuclides in muscle and bone of deer and elk from LANL lands were not significantly higher (p<0.10) than in similar tissues from deer (n = 3) and elk (n = 7) collected from BG locations. Also, elk that had been radio collared and tracked for two years and spent an average time of 50% on LANL lands were not significantly different in most radionuclides from road kill elk that have been collected as part of the environmental surveillance program. Overall, the upper (95%) level net CEDEs (the CEDE plus two sigma for each radioisotope minus background) at the most conservative ingestion rate (50 lbs of muscle and 13 lbs of bone) were as follows: deer muscle = 0.22 mrem y^‐1 (2.2 μSv y^‐1), deer bone = 3.8 mrem y^‐1 (38 μSv y^‐1), elk muscle = 0.12 mrem y^‐1 (1.2 μSv y^‐1), and elk bone = 1.7 mrem y^‐1 (17 μSv y^‐1). All CEDEs were far below the International Commission on Radiological Protection guideline of 100 mrem y^‐1 (1000 μSv y^‐1), and the highest muscle plus bone net CEDE corresponded to a RECF of 2E‐06, which is far below the Environmental Protection Agency upper level guideline of 1E‐04.     

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.