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51.
Tree bark as a passive air sampler to indicate atmospheric polybrominated diphenyl ethers (PBDEs) in southeastern China 总被引:1,自引:0,他引:1
Xiaoxu Fu Junxia Wang Xiaoyu Zhou Jingjing Deng Yangcheng Liu Wei Zhang Lili Liu Liang Dong Kuangfei Lin 《Environmental science and pollution research international》2014,21(12):7668-7677
The different barks were sampled to discuss the influence of the tree species, trunk circumference, and bark thickness on the accumulation processes of polybrominated diphenyl ethers (PBDEs) from air into the bark. The results of different PBDE concentrations indicated that barks with a thickness of 0–3 mm collected from weeping willow, Camphor tree, and Masson pine, the trunk circumferences of which were 100 to 150 cm, were better PBDEs passive samplers. Furthermore, tree bark and the corresponding air samples were collected at Anji (AJ), Hangzhou (HZ), Shanghai (SH), and Wenling (WL) to investigate the relationship between the PBDE concentrations in bark and those in air. In addition, the significant correlation (r 2?=?0.906; P?<?0.05) indicated that atmospheric PBDEs were the principle source for the accumulation of PBDEs in the barks. In this study, the log K BA (bark–air partition coefficient) of individual PBDE congeners at the four sites were in the range from 5.69 to 6.79. Finally, the total PBDE concentration in WL was 5 to 20 times higher than in the other three cities. The result indicated that crude household workshops contributed a heavy amount of PBDEs pollution to the environment, which had been verified by the spatial distribution of PBDEs levels in barks collected at Wenling (range, 26.53–1317.68 ng/g dw). The good correlation between the PBDE concentrations in the barks and the air samples and the variations of the PBDE concentrations in tree barks collected from different sites reflected that the bark could be used as a passive sampler to indicate the atmospheric PBDEs. 相似文献
52.
污泥浓缩作为污泥处理的关键环节之一,开发高效的污泥浓缩工艺对于降低污泥含水率、提高脱水设备的运行效率、降低脱水能耗具有十分重要的意义。针对MBR污泥浓度高、污泥粒径小、污泥沉降性能较差等特点,故采用传统的重力浓缩和机械浓缩技术很难有效实现污泥浓缩。因此,尝试采用气浮浓缩技术降低污泥含水率的可行性。从气浮浓缩的中试结果来看,较适宜运行参数为:固体负荷为15 kg/(m2·h),水力负荷为1.5 m3/(m2·h),回流比为1,PAM投配率2‰(w/w干固体),溶气压力为0.4 MPa,气固比为0.03。经过中试设备进行气浮浓缩后,污泥含水率降低至96%左右。此外,还研究了采用气液多相泵系统对剩余污泥的浓缩效率,结果显示,该设备的使用相对于传统溶气气浮工艺,其优点表现在占地小、工程造价低以及运行成本低等方面。 相似文献
53.
54.
Fu Li Chen Yi Yang Xinyi Yang Zuyao Liu Sha Pei Lei Feng Baixiang Cao Ganxiang Liu Xin Lin Hualiang Li Xing Ye Yufeng Zhang Bo Sun Jiufeng Xu Xiaojun Liu Tao Ma Wenjun 《Environmental science and pollution research international》2019,26(20):20137-20147
Environmental Science and Pollution Research - Fetal growth has been demonstrated to be an important predictor of perinatal and postnatal health. Although the effects of maternal exposure to air... 相似文献
55.
Songjun Guo Sheng Wen Xinming Wang Guoying Sheng Jiamo Fu Ping Hu Yingxin Yu 《Atmospheric environment (Oxford, England : 1994)》2009,43(22-23):3489-3495
Formaldehyde and acetaldehyde are two most abundant carbonyls in ambient air. Biogenic emission has been proposed as a significant source other than anthropogenic emissions and atmospheric secondary formation. Here at a forest site in South China, the carbon isotopic compositions of formaldehyde and acetaldehyde emitted from leaves of three tree species (Litsea rotundifolia, Canarium album and Castanea henryi) were measured in comparison with the bulk carbon isotopic compositions of tree leaves. δ13C data of the emitted aldehydes (from ?31‰ to ?46‰) were quite different for tree species, which were all more depleted in 13C than the tree-leaf bulk δ13C values (from ?27‰ to ?32‰). Formaldehyde in ambient air at the forest site had δ13C values different from those of leaf-emitted formaldehyde, indicating other sources for ambient formaldehyde apart from direct emission from leaves, most probably the photooxidation of biogenic hydrocarbon like isoprene and monoterpene. The δ13C differences of acetaldehyde between ambient data and those of tree leaves emission were less than 1‰, implying direct biogenic emission as the dominant source. 相似文献
56.
反渗透处理稀土氨氮废水试验研究 总被引:4,自引:2,他引:2
根据稀土冶炼厂排放的碳铵沉淀洗涤废水的水质情况,采用NH4Cl和 NaCl模拟废水进行了反渗透可行性对比实验。模拟实验发现,在相同条件下反渗透对NaCl 较NH4Cl 有着更高的去除率,而NH4Cl 相对NaCl则有着更高的产水速率。实际废水试验结果表明,在恒定操作压力范围内回收率为65%的条件下,NH4Cl浓度为2.85 g/L的碳铵沉淀洗涤废水经反渗透处理其NH4Cl去除率为77.3%,可作为氨氮废水的预处理。对该废水处理成本进行了分析,得出其约为2.7元/m3,比相近浓度氨氮废水的氨吹脱处理成本节省约26%。 相似文献
57.
好氧硝化颗粒污泥膜生物反应器性能和膜污染研究 总被引:4,自引:3,他引:1
实验研究了好氧硝化颗粒污泥膜生物反应器AGMBR的处理性能,并将其与活性污泥膜生物反应器ASMBR进行对比,考察了颗粒污泥在减缓膜污染中所起的作用.好氧硝化颗粒污泥膜生物反应器AGMBR连续稳定运行102 d,系统具有良好的去除有机物和同时硝化反硝化能力,在进水COD和NH+4-N浓度分别为500和200 mg/L时,COD、NH+4-N和TN的去除率分别稳定在86%、94%和45%以上.颗粒污泥有效减缓了膜污染,延长了膜清洗的周期,AGMBR中的膜污染以膜孔堵塞为主,占总阻力的64.81%;滤饼层的阻力为2.1×1012m-1,远小于ASMBR中的16.07×10"m-1;膜清洗周期是相同条件下ASMBR的2.43倍以上;而且AGMBR内不断有新颗粒生成,维持了AGMBR系统性能和运行的稳定. 相似文献
58.
Duohong Chen Xinhui Bi Jinping Zhao Laiguo Chen Jihua Tan Bixian Mai Jiamo Fu Minghung Wong 《Environmental pollution (Barking, Essex : 1987)》2009,157(3):1051-1057
Diurnal air samples were collected from the E-waste dismantling region Guiyu and the underwear industry region Chendian. This was the first report to present the diurnal variation of PBDEs in the atmosphere. The average concentrations of 11 PBDE congeners were 11,742 pg m−3 in the daytime, and 4830 pg m−3 at night in Guiyu, while the concentrations were lower in Chendian with 376 pg m−3 in the daytime, and 237 pg m−3 at night. BDE-209 accounted for 22% and 31.3% of the total PBDEs in Guiyu and Chendian, respectively. The diurnal variation trends of BDE-47, -99, -153, -183, and -209 were also analyzed in detail in the two regions. 相似文献
59.
Qiang Liu Mi Li Rong Chen Zhengyue Li Guangren Qian Taicheng An Jiamo Fu Guoying Sheng 《Waste management (New York, N.Y.)》2009,29(7):2051-2058
An in situ compost biofilter was established for the treatment of odors from biostabilization processing of municipal solid waste. The concentrations of total volatile organic compounds (VOCs) in odors and their components were measured. Biofilter media was characterized in terms of total carbon (TC), total nitrogen (TN), total phosphorus (TP), organic matter (OM), pH value and determination of bacterial colony structure. Gas chromatography–mass spectrometry (GC–MS) analysis showed that the main components of the produced gas were benzene, toluene, ethylbenzene and xylene (BTEX) along with other alkanes, alkenes, terpenes, and sulphur compounds. The compost biofilter had remarkable removal ability for alkylated benzenes (>80%), but poor removal for terpenes (~30%). Total VOC concentrations in odors during the biostabilization process period ranged from 0.7 to 87 ppmv, and the VOC removal efficiency of the biofilter varied from 20% to 95%. After about 140 days operation, TN, TC, TP and OM in compost were kept almost stable, but the dissolved N, NH4–N and NO3–N experienced an increase of 44.5%, 56.2% and 76.3%, respectively. Dissolved P decreased by 27.3%. The pH value experienced an increase in the early period and finally varied from 7.38 to 8.08. Results of bacterial colony in packing material indicated that bacteria and mold colony counts increased, but yeasts and actinomyces decreased along with biofilter operation, which were respectively, 3.7, 3.4, 0.04 and 0.07 times of their initial values. 相似文献
60.
Xinyi Dong Joshua S. Fu 《Journal of the Air & Waste Management Association (1995)》2013,63(12):1317-1332
ABSTRACTVolatile organic compounds (VOCs) evaporate and vent from a vehicle’s fuel tank to its evaporative control system when the vehicle is both driven and parked. VOCs making it past the control system are emissions. Driving and parking activity, fuel volatility, and temperature strongly affect vapor generation and the effectiveness of control technologies, and the wide variability in these factors and the sensitivity of emissions to these factors make it difficult to estimate evaporative emissions at the macro level. Established modeling methods, such as COPERT and MOVES, estimate evaporative emissions by assuming a constant in-use canister condition and consequently contain critical uncertainty when real conditions deviate from that standard condition. In this study, we have developed a new method to model canister capacity as a representative variable, and estimated emissions for all parking events based on semi-empirical functions derived from real-world activity data and laboratory measurements. As compared to chamber measurements collected during this study, the bias of the MOVES diurnal tank venting simulation ranges from ?100% to 129%, while the bias for our method’s simulation is 1.4% to 8.5%. Our modeling method is compared to the COPERT and MOVES models by estimating evaporative emissions from a Euro-3/4/5 and a Tier 2 vehicle in conditions representative for Chicago, IL, and Guangzhou, China. Estimates using the COPERT and MOVES methods differ from our method by ?56% to 120% and ?100% to 25%, respectively. The study highlights the importance for continued modeling improvement of the anthropogenic evaporative emission inventory and for tightened regulatory standards.Implications: The COPERT and MOVES methodologies contain large uncertainties for estimating evaporative emissions, while our modeling method is developed based on chamber measurements to estimate evaporative emissions and can properly address those uncertainties. Modeling results suggested an urgent need to complete evaporative emissions inventories and also indicated that tightening evaporative emission standards is urgently needed, especially for warm areas. 相似文献