共查询到20条相似文献,搜索用时 46 毫秒
1.
Measurements of aerosol size-separated number concentrations were performed in March 2001 on the Tama Hills of Japan, located
near regions of heavy industry. The concentrations of particles larger than 1.0 μ m in diameter dramatically increased during
the Kosa phenomena on 6–8 and 18–24 March. The number concentrations of coarse particles (> 3.0 μm) showed distinct diurnal
variations, especially during the Kosa events. Fine particles smaller than 0.5 μm increased when the relative humidity was
high and the wind speed was low. On the other hand, the coarse particles concentrations were well correlated with wind speed
and temperature. The dry deposition velocity of the coarse particles at the forest canopy was estimated from the nighttime
decrease in the number concentrations. 相似文献
2.
M. Yamada Y. Iwasaka A. Matsuki D. Trochkine Y. S. Kim D. Zhang T. Nagatani G.-Y. Shi M. Nagatani H. Nakata Z. Shen B. Chen G. Li 《Water, Air, & Soil Pollution: Focus》2005,5(3-6):231-250
Free tropospheric aerosol particles were collected using a balloon-borne particle impactor in August of 2002 and March of
2003 at Dunhuang in northwestern China (40°00′N, 94°30′E), and the morphology and elemental composition of the aerosol particles
were analyzed in order to understand the mixing state of coarse dust particles (diameter >1 μm) over the desert areas in the
Asian continent in spring. Electron microscopic experiments on the particles revealed that dust particles were major constituents
of coarse mode particles in the free troposphere over the Taklamakan Desert in spring and summer.
Si-rich or Ca-rich particles are major components of dust particles collected in the free troposphere over dunhuang and the
values of [number of Ca-rich particles]/[number of Si-rich particles] differs markedly between spring and summer, being about
0.3 in the spring of 2003 and about 1.0 in the summer of 2002 at heights 3–5 km above sea level. It is likely that the condition
of the ground surface and the strength of vertical mixing in source areas of Asian dust are potential factors causing the
difference in the chemical types of dust particles.
Comparison of the elemental compositions of these particles with those of particles collected over Japan strongly suggests
that these particles were chemically modified during their long-range transport in the free troposphere. Analysis of wind
systems shows that both the predominating westerly wind in the free troposphere and the surface wind strongly controlled by
the geographical structure of the Tarim Basin are important in the long-range transport of KOSA particles originating in the
Taklamakan Desert. 相似文献
3.
Biodegradation of Polycaprolactone Powders Proposed as Reference Test Materials for International Standard of Biodegradation Evaluation Method 总被引:1,自引:0,他引:1
Masahiro Funabashi Fumi Ninomiya Masao Kunioka 《Journal of Polymers and the Environment》2007,15(1):7-17
Polycaprolactone (PCL) powders were prepared from PCL pellets using a rotation mechanical mixer. PCL powders were separated
by sieves with 60 and 120 meshes into four classes; 0–125 μm, 125–250 μm, 0–250 μm and 250–500 μm. Biodegradation tests of
PCL powders and cellulose powders in an aqueous solution at 25°C were performed using the coulometer according to ISO 14851.
Biodegradation tests of PCL powders and cellulose powders in controlled compost at 58°C were performed by the Mitsui Chemical
Analysis and Consulting Service, Inc. according to ISO 14855-1 and by using the Microbial Oxidative Degradation Analyzer (MODA)
instrument according to ISO/DIS 14855-2. PCL powders were faster biodegraded than cellulose powders. The reproducibility of
biodegradation of PCL powders is excellent. Differences in the biodegradation of PCL powders with different class were not
observed by the ISO 14851 and ISO/DIS 14855-2. An enzymatic degradation test of PCL powders with different class was studied
using an enzyme of Amano Lipase PS. PCL with smaller particle size was faster degraded by the enzyme. PCL powders with regulated sizes from 125 μm to 250 μm
are proposed as a reference material for the biodegradation test. 相似文献
4.
PM<Subscript>10</Subscript> and Ultrafine Particles Counts In-Vehicle and On-Road in the Athens Area
E. Diapouli G. Grivas A. Chaloulakou N. Spyrellis 《Water, Air, & Soil Pollution: Focus》2008,8(1):89-97
This work presents the first results of a study concerning on-road and in-vehicle exposure to particulate matter in the area
of Athens. PM10 concentration measurements were conducted by TSI DustTrak, while driving along routes with different characteristics of traffic
density, during September 2003–March 2004. Concurrent measurements of the ultrafine particles (UFPs) number concentration
were also conducted, by condensation particle counter during part of the days. Pedestrian exposure to PM10 and UFPs was also studied through stationary measurements on the kerbside of selected roads on November 2003 and February
2004. A major avenue, a heavy-trafficked road across a children hospital and two central roads, one in a residential and one
in a commercial area were selected for measurement. The results indicate that every day commuters are exposed to significant
concentration levels. Higher exposures were observed in heavy-trafficked areas and during rush hours. Mean PM10 in-vehicle and on-road concentrations ranged from 30–320 μg/m3 and 70–285 μg/m3, respectively. The ultrafine particles number concentrations were in the range of 5.0 × 104–17.3 × 104 particles/cm3 in-vehicle and 3.1 × 104–7.3 × 104 particles/cm3 on the kerbside of a central residential road. Both PM10 and UFPs concentrations presented repeated short-term peak exposures. The results clearly point out the importance of the
road microenvironment (in-vehicle and on kerbside) for population exposure in urban areas. 相似文献
5.
Ian Colbeck Zaheer Ahmad Nasir Shahida Hasnain Sikander Sultan 《Water, Air, & Soil Pollution: Focus》2008,8(1):61-69
In the developing world, the vast majority of people rely on solid biomass fuels for cooking and heating which results in
poor indoor air quality. The present study determined indoor air quality in some rural and urban areas of Pakistan. Measurements
were made of particulate mass (PM10, PM2.5 and PM1), number concentration and bioaerosols in different micro environments.
PM10 concentrations of up to 8,555 μg/m3 were observed inside the kitchens where biofuels were used as energy source. Cleaning and smoking was identified as a major
source of indoor particulate pollution and concentrations of more than more than 2,000 μg/m3 were recorded in the living room during these activities. Indoor number concentrations in Lahore were typically greater than
those observed outdoors in European cites. At a rural site the highest Colony Forming Units (CFUs) were in the 0.5 μm–2 μm
size fraction, while at the urban location CFUs were dominant for 2 μm–16 μm. It was observed that CFUs(Colony Forming Units)
counts were higher inside living rooms than kitchens. It is important to note that women and children were exposed to extremely
high levels of particulates during cooking. Overall, indoor air quality in Pakistan was poor and there is a dire need to take
a serious step to combat with it. 相似文献
6.
Ping-Ping Shen Hong Zhou Ho-Yan Lai Ji-Dong Gu 《Water, Air, & Soil Pollution: Focus》2006,6(5-6):575-581
Benthic infaunal communities at Mai Po Inner Deep Bay mudflat, Hong Kong were investigated between August 2002 and August
2003. A total of 55 species belonging to 8 Phyla from more than 99,074 specimens were recorded. The species richness varied
between 13 at Station B in August 2002 and 28 at Station D in August 2003 with an average of 21 across the mudflat and the
species diversity was low [H′(log2) = 0.7–3.5 with an average H′ = 2.4]. Seasonal variations were also observed through abundance and biomass across the mudflat among the seasons. The abundance
density was between 8,977 individuals m−2 at Station D in February 2003 and 77,256 individuals m−2 at Station B in November 2002 and the overall average density was 25,274 individuals m−2 for the four stations. The benthic infauna were dominated by pollution tolerant species at this wetland mudflat. 相似文献
7.
Chung Yong-Seung Kim Hak-Sung Park Kie-Hyon Dulam Jugder Gao Tao 《Water, Air, & Soil Pollution: Focus》2005,5(3-6):15-35
A joint monitoring of dust-storms that occurred in East Asia from March until May 2003 has been carried. Our discussions include
dust-storm observations in the source areas of China and Mongolia, and measurements with satellites and ground monitors in
central Korea. Differences were found in the definition and measurement of dust-storms. Over the source area of Mongolia there
were 6 dusty days in March, 18 days in April, and 10 dusty days in May. In Inner Mongolia of northern China there were 4 dust-storms
with 14 dusty days observed over the three months. In central Korea, a sink area, there were 4 cases of weak dust-storm and
17 dusty days in the spring of 2003. The highest PM10 value was 607 μgm−3 and PM 2.3 was 149 μgm−3, respectively. These observations identify the growing need for further universal observation practices and dust-storm reporting
in future.
Observations indicated that snow covered the central part of the Gobi Desert, near the boundary of China and Mongolia, from
December until mid-March. This is in contrast to other years when the Gobi was relatively wet, producing unfavourable conditions
for the formation of intense dust-storms. In addition, the very strong winds associated with intense cyclones and anticyclones
were not apparent and the systems shifted northward during the spring. As a result, the frequency and intensity of observed
dust-storms in 2003 in this region were very low. This confirms that there is variability in the frequency of dust-storm formation
due to the current process of desertification and climate change. 相似文献
8.
Airborne particulate matter (PM) concentrations were measured in Iksan, a suburban area in South Korea during April, 2003.
PM2.5 (particles with an aerodynamic diameter less than 2.5 μm) and PM10 (particles with an aerodynamic diameter less than 10 μm) samples were collected, and the chemical characteristics of particles
were examined for diurnal patterns, yellow dust/rainfall influences, and scavenging effects. Average concentrations of PM2.5 and PM10 mass measured were 37.3 ± 16.2 μg m−3 and 60.8 ± 29.5 μg m−3, respectively. The sum of ionic chemical species concentrations for PM2.5 and PM10 was 16.9 ± 7.3 and 23.1 ± 10.1 μg/m3, respectively. A significant reduction in PM mass concentrations during rainfall days was observed for coarse mode (PM2.5 − 10) particles, but less reduction was found for fine (PM2.5) mass concentration. SO4
2−, NH4
+, and K+ predominated in fine particulate mode, NO3
− and Cl− predominated in fine particle mode and coarse particle mode, but Na+, Mg2+, and Ca2+ mostly existed in coarse mode. The high concentration of ammonium due to local emissions and long-range transport neutralized
sulfate and nitrate to ammonium sulfate and ammonium nitrate, which were major forms of airborne PM in Iksan. Average mass
concentrations of PM10 in daytime and at night were 57.6 and 70.0 μg m−3, and those of PM2.5 were 35.4 and 42.5 μg m−3, respectively. NO3
− and Cl− in both PM2.5 and PM10 were about double at night than in the daytime, while the rest of the chemical species were equal or a little higher at night
than in the daytime. The results suggest the formation of ammonium nitrate and chloride when high ammonia concentration and
low air temperature are allowed. Backward air trajectory analyses showed that air masses arriving at the site during yellow
dust period were transported from arid Chinese regions, which resulted in high concentrations of airborne PM mass concentrations.
In the meantime, air mass trajectories during a rainfall period were mostly from the Pacific Ocean or the East China Sea,
along with a relatively low PM concentration. 相似文献
9.
Masahiro Shimada Takahiko Iida Kensuke Kawarada Yoshifumi Chiba Toshihiro Mamoto Takayuki Okayama 《Journal of Material Cycles and Waste Management》2000,2(2):100-108
In an earlier report, we presented a method for preparing activated carbon from waste newspaper as a way to recycle used paper
for a purpose other than producing raw material for paper-making. In this article, we consider the porous structure of the
activated carbon that affects its adsorption properties for various substances. The specific surface area of activated carbon
prepared from waste newspaper was 838 m2/g, the micropore volume was 0.368 ml/g, and the mesopore volume was 0.138 ml/g, which is about the same as commercially available
activated carbon. The activated carbon prepared from waste newspaper usually has a high content of ash, which makes little
contribution to the adsorption properties. In particular, as compared with reagent-activated carbon, the quantities of mesopores
with a pore radius of 3–25 nm and macropores with a pore radius of 25–250 nm were 8 and 14 times larger, respectively. Activated
carbon prepared from waste newspaper has a well-developed porous structure, particularly in the mesopore and macropore ranges.
Received: July 12, 1999 / Accepted: March 8, 2000 相似文献
10.
Shaodong Xie Yuanhang Zhang Li Qi Xiaoyan Tang 《Water, Air, & Soil Pollution: Focus》2005,5(3-6):217-229
In the Beijing area, March and April have the highest frequency of sand-dust weather. Floating dust, blowing sand, and dust
storms, primarily from Mongolia, account for 71%, 20%, and 9% of sand-dust weather, respectively. Ambient air monitoring and
analysis of recent meteorological data from Beijing sand-dust storm periods revealed that PM10 mass concentrations during dust storm events remained at 1500 μg m−3, which is five to ten times higher than during non-dust storm periods, for fourteen hours on both April 6 and 25, 2000. During
the same period, the concentrations in urban areas were comparable to those in suburban areas, while the concentrations of
gaseous pollutants, such as SO2, NO
x
, NO2, and O3, remained at low levels, owing to strong winds. Furthermore, during sand-dust storm periods, aerosols were created that consisted
not only of many coarse particles, but also of a large quantity of fine particles. The PM2.5 concentration was approximately 230 μg m−3, accounting for 28% of the total PM10 mass concentration. Crustal elements accounted for 60–70% of the chemical composition of PM2.5, and sulfate and nitrate for much less, unlike the chemical composition of PM2.5 on pollution days, which was primarily composed of sulfates, nitrates, and organic material. Although the very large particle
specific surface area provided by dust storms would normally be conducive to heterogeneous reactions, the conversion rate
from SO2 to SO4
2− was very low, because the relative humidity, less than 30%, was not high enough. 相似文献
11.
Ken’ichiro Matsumoto Yuko Arai Rina Nagao Takaaki Murata Kazuma Takase Hideo Nakashita Seiichi Taguchi Hiroaki Shimada Yoshiharu Doi 《Journal of Polymers and the Environment》2006,14(4):369-374
In this paper, the photosynthetic production of short-chain-length/medium-chain-length polyhydroxyalkanoate (PHA) copolymers is reported. The wild-type and highly active doubly mutated PHA synthase 1 (S325T/Q481K, abbreviated ST/QK) genes from Pseudomonas sp. 61-3 were introduced into Arabidopsis thaliana. Peroxisome targeting signal 1 (PTS1) was used to target PHA synthases into the peroxisome to synthesize PHA from the intermediates of the β-oxidation pathway. The transgenic Arabidopsis produced PHA copolymers consisting of 40–57 mol% 3-hydroxybutyrate, 21–49 mol% 3-hydroxyvalerate, 8–18 mol% 3-hydroxyhexanoate, and 2–8 mol% 3-hydroxyoctanoate. The maximum PHA contents were 220μ g/g cell dry weight (cdw) in leaves, and 36μ g/g cdw in stems, respectively. The expression of the ST/QK mutated PHA synthase in leaves gene did not lead to significant difference in PHA content and monomer composition of PHAs, compared to the wild-type PHA synthase gene, suggesting that the supply of monomers may be a rate-determining step of PHA biosynthesis in the peroxisome. However, in stems, there were significant differences dependent on whether the wild-type or ST/QK mutated PHA synthase was expressed. These results suggest that tissue-specific monomer availability is important in determining the final mol% composition of PHA copolymers produced by the peroxisome in plants. 相似文献
12.
Yukio Noma Sayuri Yamane Akiko Kida 《Journal of Material Cycles and Waste Management》2001,3(2):126-134
Adsorbable organic halides (AOX) and AOX formation potential (AOXFP) were investigated in 46 landfill lea-chates as potentially
toxic parameters. AOX in landfill leachate was within the range <10–2200 μg Cl/l, and AOXFP was within 51–15 000 μg Cl/l.
AOX and AOXFP correlated with chemical oxygen demand (COD). AOX discharge from closed landfills was generally lower than that
from operating landfills. The molar ratio of AOXFP/total organic carbon (TOC) suggested that organic compounds in a leachate
have a double bond every 15–190 carbons under the supposition that one chlorine would add to one double bond. The five landfills
discharging high-level AOXFP (>4000 μg Cl/l) were all landfills where sludge had been dumped. The removal efficiencies of
three parameters through leachate treatment processes were as follows: polychlorinated dibenzo-dioxins/dibenzo-furans (PCDDs/DFs)
> TOC > AOX. PCDDs/DFs were substantially removed at p.p.t. levels, while AOX was hardly removed at relatively low levels.
Received: February 14, 2000 / Accepted: January 9, 2001 相似文献
13.
Yasunori Kawagoshi Isao Fukunaga Hisao Itoh 《Journal of Material Cycles and Waste Management》1999,1(1):53-61
Organophosphoric acid triester (OPE) concentration levels in water and bottom sediment at the Osaka North Port Sea-Based Solid
Waste Disposal Site were investigated, and the behavior of OPEs in the water environment of the waste disposal site was examined.
The more highly water-soluble OPEs were frequently detected in raw water. Of the OPEs detected, TCEP and TCPP showed very
high concentrations (1.0–90 μg/l), followed by TEP (0.3–10 μg/l) > TBXP (0.8–6.3 μg/l) > TDCPP (0.6–6.2 μg/l) > TBP (0.2–1.5 μg/l)
> TPP (<0.1 μg/l). Most OPEs detected in water were eluted from the disposal waste to the water phase immediately and behaved
as dissolved forms with no distribution in suspended solids (SS). On the other hand, the less water-soluble OPEs, such as
TCP or TEHP, were detected in bottom sediment but hardly at all in water samples. All OPEs were detected at the waste disposal
site, within which their concentration levels were uniform. It appeared that the less water-soluble OPEs were present as SS-associated
forms and behaved in line with the floating surface sludge at the bottom.
Received: July 6, 1998 / Accepted: February 25, 1999 相似文献
14.
Shin-ichi Sakai Yasuhiro Hirai Hirofumi Aizawa Shizuko Ota Yasuhiro Muroishi 《Journal of Material Cycles and Waste Management》2006,8(1):56-62
Atmospheric emissions of deca-brominated diphenyl ether (DBDE) in Japan were estimated based on the material flow of DBDE
products and their emission factors. In 2002, the demand for DBDE in Japan was 2200 ton/year and the stock level was about
60 000 ton. The DBDE flow into the waste stream was estimated to be about 6000 ton/year and the flow out through second-hand
product exports was more than 700 ton/year. Home appliance recycling facilities dismantle and crush domestic wastes containing
about 600 ton of DBDE annually. Material recycling of crushed plastics is not commonly practiced as yet. Emission factors
from plastics processing (2 × 10−9–1 × 10−7), textile processing (9 × 10−7), home appliance recycling (8 × 10−9–5 × 10−6), and waste incineration (1 × 10−7–2 × 10−6) were estimated using field measurement data. The DBDE emission rate through house dust during the service life of final
products (2 × 10−7–9 × 10−7 per year) was estimated using the DBDE concentration in dust and the amount of dust in used televisions. Emission factors
from previous studies were also used. The estimated total DBDE emission was 170–1800 kg/year. These results suggest the necessity
of characterizing emissions during the service life of products, which is essential information for formulating an appropriate
e-waste recycling strategy. 相似文献
15.
Jugder Dulam 《Water, Air, & Soil Pollution: Focus》2005,5(3-6):37-49
A discriminate analysis method for probability forecast of dust storms in Mongolia has been developed. The prediction method
uses data recorded at 23 meteorological stations in the Gobi and steppe regions of Mongolia, including surface air pressure
and geo-potential height at the 500-hPa level on grid points, and weather maps from 1975 to 1990.
Weather elements such as air temperature, pressure, geo-potential height etc, which influence the formation of dust storms,
are prepared as predictors. To select the most informative/important predictors (variables), we used a mean correlation matrix
of variables together with the Mahalonobis distance, and correlation coefficients between dust storms and predictors with
an orthogonalization for removing correlated predictors. The most informative predictors for dust storm prediction are intensities
of surface cyclones and migratory anticyclones, passage of cold fronts, the horizontal gradients of the surface air pressure
in the cold frontal zone, cyclonic circulations from the ground surface up to the 500-hPa level, the geo-potential height
at 500-hPa level and its temporal changes.
Selected predictors are used in discriminate analysis for formulating dust storm prediction equations. Sandstorm data have
been classified into three classes, viz., strong, moderate and weak dust storms, depending on their intensities, durations
and areas covered. Predictions of the probabilities of dust storm occurrence use the prediction equations for each class.
The prediction is made from 12 hours to 36 hours.
Verification of the probability forecasts of dust storms is also shown. The accuracy of forecasts is 72.2–79.9% with the data
used for developing equations (dependent variables), in contrast to 67.1–72.0% with unrelated data for deriving equations
(independent variables). 相似文献
16.
Shin-ichi Sakai Takahiro Ukai Hiroshi Takatsuki Kazuo Nakamura Sayuri Kinoshita Takumi Takasuga 《Journal of Material Cycles and Waste Management》1999,1(1):62-74
Previous reports have focused on the emission of coplanar polychlorinated biphenyls (Co-PCBs) which have a toxic mechanism
similar to that of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/DFs) released from municipal solid waste (MSW) incineration. Such emissions
accounted for a small percentage of all the dioxins (PCDDs/DFs and Co-PCBs) recorded at the toxicity equivalent (TEQ) level.
There is, however, very little information about Co-PCBs, such as the quantities being released and their effect on overall
environmental pollution. The aim of this research has been to clarify the substance flow of Co-PCBs from MSW incineration
processes. The results reveal that whereas the input of Co-PCBs into the MSW incineration facilities in Kyoto City was 0.13–0.29 μg-TEQ
per ton waste, the total output of Co-PCBs (the sum of Co-PCBs released from emission gas, fly ash, and bottom ash) was 4.9 μg-TEQ
per ton waste. The total output was therefore found to be higher than the total input. Over 90% of the total PCBs were decomposed
in the incineration process. In comparing the profiles of congeners and homologues, those in the MSW were found to be similar
to those detected in the atmosphere and products containing PCBs, but different from those in the MSW incineration gas.
Received: August 26, 1998 / Accepted: March 2, 1999 相似文献
17.
A. Matsuki Y. Iwasaka G.-Y. Shi H.-B. Chen K. Osada D. Zhang M. Kido Y. Inomata Y.-S. Kim D. Trochkine C. Nishita M. Yamada T. Nagatani M. Nagatani H. Nakata 《Water, Air, & Soil Pollution: Focus》2005,5(3-6):101-132
This study focuses on providing a direct insight into the process by which sulfate is formed on mineral dust surface in the
actual atmosphere. Six sets of aerosol measurements were conducted in the outskirts of Beijing, China, in 2002–2003 using
a tethered balloon. The mineralogy of individual dust particles, as well as its influence on the S (sulfur) loadings was investigated
by SEM-EDX analysis of the directly collected particles.
The mixed layer in the urban atmosphere was found to be quite low (500–600m), often appearing as a particle dense stagnant
layer above the surface. It is suggested that mineral dust is a common and important fraction of the coarse particles in Beijing
(35–68%), and that it is relatively enriched with Calcite (>28%).
An exceptional amount of S was detected in the mineral particles, which can be explained neither by their original composition,
nor by coagulation processes between the submicron sulfates and the dust. Heterogeneous uptake of gaseous SO2, and its subsequent oxidation on dust was suggested as the main pathway that has actually taken place in the ambient environment.
The mineral class found with the largest number of particles containing S was Calcite, followed by Dolomite, Clay, Amphibole
etc., Feldspar, and Quartz. Among them, Calcite and Dolomite showed distinctly higher efficiency in collecting sulfate than
the other types.
A positive correlation was found with the number of S containing particles and the relative humidity. Calcite in particular,
since almost all of its particles was found to contain S above 60% r.h. On the other hand, the active uptake of SO2 by the carbonates was not suggested in the free troposphere downwind, and all the mineral classes exhibited similar S content.
Relative humidity in the free troposphere was suggested as the key factor controlling the SO2 uptake among the mineral types. In terms of sulfate loadings, the relationship was not linear, but rather increased exponentially
as a function of relative humidity. The humidity-dependent uptake capacity of mineral types altogether showed an intermediate
value of 0.07 gSO4
2− g−1 mineral at 30% r.h. and 0.40 gSO4
2− g−1 mineral at 80%, which is fairly consistent with laboratory experiments. 相似文献
18.
Jung-Eun Lee 《Journal of Material Cycles and Waste Management》2011,13(3):259-263
Effective handling of municipal digested sludge requires that the product cake have low water content. To this end, we investigated
the change in sludge dewaterability after the addition of fly ash to municipal digested sludge, dewatering of which is difficult
because of its high organic content. The performance of the dewatering is compared with that of electroosmotic dewatering
(EDW) and conventional mechanical dewatering (CMD). Fly ash classified by sieving to the size of 25–75 μm and >75 μm is added
to the municipal digested sludge by 10, 20, and 50 wt% by wet base. When adding fly ash particles to municipal digested sludge,
dewatering efficiency improved with smaller fly ash particle size and with increase in the amount. When sludge was dewatered
using an electroosmotic dewatering method, the dewatering efficiency is improved about 40% by adding fly ash of 25–75 μm particle
size with 20 wt% when compared with conventional mechanical dewatering method without adding the fly ash. It is concluded
that fly ash particles rich in inorganic material are helpful in the dewatering process when added to municipal digested sludge
and EDW is more effective than CDW. 相似文献
19.
Kunichika Nakamiya Tohru Furuichi Kazuei Ishii 《Journal of Material Cycles and Waste Management》2002,4(2):127-134
This article reports the potential of denitrifying activated sludge to degrade highly chlorinated dioxins, especially from
a (landfill) leacheate treatment plant in Japan, and the isolation from this denitrifying activated sludge of a microorganism
able to degrade highly chlorinated dioxins. Using a 700-ml bioreactor, denitrifying activated sludge was cultivated under
denitrifying conditions by adding 2.0 ng of a mixture of 4- to 8-chlorinated dioxins from fly ash. The dioxin contents of
the sample, effluent, and medium before and after cultivation were measured by gas chromatography–mass spectrometry (GC–MS).
After 7 days cultivation, about 90% of added dioxins were lost (average percentage of isomer depletion). A dioxin-degrading
microorganism was isolated from the activated sludge. Lignin was added to the medium as a color indicator of aromatic compound
degradation, and the lignin-decolorizing microorganisms in the denitrifying activated sludge were screened. Some strains were
isolated, and one major isolated fungus, strain 622, decolorized lignin effectively. Strain 622 was identified as an Acremonium sp. from its morphological characteristics. It could decolorize lignin by 24% under paraffin-sealed anaerobic conditions.
After the cultivation of strain 622 with a 2 ng/ml mixture of 4- to 8-chlorinated dioxins for 1 day, 82% (average for individual
isomers) of the added 4- to 8-chlorinated dioxins had been degraded. Added octachlorodibenzo-p-dioxin (OCDD, 100 ng) was degraded under aerobic conditions after 8 h of incubation. During this process, heptachlorodibenzo-p-dioxin was produced and appeared to be a degradation product of OCDD. 1- or 2-hydroxydibenzo-p-dioxin from OCDD was also identified as the degradation product by GC–MS. These results indicated that OCDD was degraded
to the nonchlorinated dibenzo-p-dioxins through dechlorination by Acremonium sp. strain 622.
Received: October 12, 2001 / Accepted: March 11, 2002 相似文献
20.
Meteorological characteristics and morphology of duststorms and other dust weather phenomena in the arid regions of East Asia
were described in order to investigate a possible role of mesoscale cloud disturbances that develop in synoptic-scale mid-latitude
cyclones in intensifying dust weather. This study is a statistical examination of conventional surface observational data
as well as satellite data obtained during April 2000–2003. In the deserts of Mongolia and northern China (e.g., the Gobi Desert)
duststorms and other weaker dust weather (i.e., dust whirls, blowing dust) frequently occur under a strong influence of synoptic-scale
cyclones; on the other hand in the Taklamakan Desert (northwestern China), dust weather phenomena occur in a less organized
fashion and may be driven mainly by local meteorological and geographical effects. A significant signal was identified, revealing
of the intensification of dust weather by the presence of convective cloud disturbances. Meteorological changes such as pressure
rise and temperature drop, typically found during the passage of cold fronts, were frequently observed in the cases of duststorms
occurring in the analysis region. However, no definite tendency was found for moisture change and wind speed in relation to
cloud activity, probably because rainfall amount is generally too low to moisten the boundary-layer air. 相似文献