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981.
Stream restoration practices are becoming increasingly common, but biological assessments of these improvements are still
limited. Rock weirs, a type of constructed riffle, were implemented in the upper Cache River in southern Illinois, USA, in
2001 and 2003–2004 to control channel incision and protect high quality riparian wetlands as part of an extensive watershed-level
restoration. Construction of the rock weirs provided an opportunity to examine biological responses to a common in-stream
restoration technique. We compared macroinvertebrate assemblages on previously constructed rock weirs and newly constructed
weirs to those on snags and scoured clay streambed, the two dominant substrates in the unrestored reaches of the river. We
quantitatively sampled macroinvertebrates on these substrates on seven occasions during 2003 and 2004. Ephemeroptera, Plecoptera,
and Trichoptera (EPT) biomass and aquatic insect biomass were significantly higher on rock weirs than the streambed for most
sample periods. Snags supported intermediate EPT and aquatic insect biomass compared to rock weirs and the streambed. Nonmetric
multidimensional scaling (NMDS) ordinations for 2003 and 2004 revealed distinct assemblage groups for rock weirs, snags, and
the streambed. Analysis of similarity supported visual interpretation of NMDS plots. All pair-wise substrate comparisons differed
significantly, except recently constructed weirs versus older weirs. Results indicate positive responses by macroinvertebrate
assemblages to in-stream restoration in the Cache River. Moreover, these responses were not evident with more common measures
of total density, biomass, and diversity. 相似文献
982.
Perceiving the Environment from the Lay Perspective in Desertified Areas,Northern China 总被引:1,自引:0,他引:1
Investigating local people’s environmental perceptions can produce useful information that could be incorporated into decision
making processes that help resolve environmental problems. Although China is undergoing severe desertification, the perceptions
of the local people toward their degraded environment and the related issues have so far not been actively solicited. This
article, which is a supplement to Lee and Zhang’s (2004, 2005) studies, seeks to further investigate the lay public’s general environmental attitudes, perceptions of desertification, interpretations
of land-degrading activities, and particularly their interrelations in severely desertified areas. Minqin County in Gansu
Province, northern China, was chosen to be the study area. Data was collected via a questionnaire survey (n = 1138) administered in December 2002. Major findings were: (1) Most respondents had only weak altruistic environmental attitudes,
with educational level to be a significant determinant. (2) Respondents’ perceptions of desertification and interpretations
of land-degrading activities were contingent on personal attributes, general environmental attitudes, and other conceptions
related to desertification. It is recommended that the interrelations between the various aspects of the public’s environmental
perceptions should be thoroughly examined to facilitate their participation in environmental management. 相似文献
983.
Anna Peterson 《Journal of Agricultural and Environmental Ethics》2008,21(6):607-608
984.
985.
986.
Sławomir Stelmach Ryszard Wasielewski 《Journal of Material Cycles and Waste Management》2008,10(2):110-115
More than 1.1 million tons of municipal and industrial sewage sludge is produced annually in Poland. Most of this sewage sludge
is landfilled or used for recultivation and fertilization of soil. After accession of Poland to the EU, large investments
are planned for wastewater treatment, so it is expected that the amount of sewage sludge produced in Poland will grow in the
near future. It is well known that the combustion of sewage sludge is becoming a more and more popular utilization method
of such waste. Unfortunately, the current situation in Poland makes it impossible to incinerate the sewage sludge because
of a lack of incinerators. One possible solution for Poland is the co-firing of dried sewage sludge in existing coal-fired
utility boilers. This article presents results of initial Polish industrial trials of dried municipal sewage sludge and hard
coal co-combustion in an OP-230 pulverized coal boiler. Such a solution was shown to be technically viable and not to require
changes to the existing technological system. Cocombustion of sewage sludge with coal in power plants seems to be the best
solution for sludge utilization in the near future in Poland. 相似文献
987.
Aishah S. A. K. Sharifah Hanafiah Zainal Abidin Mohamad R. Sulaiman Kheng H. Khoo Hairi Ali 《Journal of Material Cycles and Waste Management》2008,10(2):116-123
Malaysia is in dire need of alternatives to landfilling for solid waste management. Recently, landfills have faced the problems
of overfilling, overflowing of leachates leading to pollution of water resources, and uncontrolled dust emissions adversely
affecting the local environment. With the rising cost of urbanization coupled with the high rate of waste generation, one
possible method of waste treatment that is receiving particular attention by the government is incineration. Incineration
of solid waste is rather new in Malaysia, with limited usage in handling small sources of waste generation such as the municipal
solid waste (MSW) of resort islands; however, its potential in ameliorating the problems associated with solid waste treatment
may make it an attractive alternative to landfill. This article presents the results of test runs conducted to investigate
the performance of a locally designed and manufactured rotary kiln incinerator (RKI). The test runs were conducted using MSW
collected from the Shah Alam municipality. The combustion efficiency was analyzed by looking at the temperature profiles and
chemical species concentrations. To complement the combustion characteristics measurements, predictions of the air flow in
the incinerator during the process were also investigated. The overall performance of the RKI suggests that it is suitable
for treating MSW. 相似文献
988.
Hang Seok Choi Seock Joon Kim Kwan Tae Kim 《Journal of Material Cycles and Waste Management》2008,10(1):1-6
The mixing characteristics of a passive scalar in the turbulent flow of a selective catalytic reduction process were numerically
and experimentally investigated, focusing especially on an injection nozzle with multiple holes for the reducing agent. The
multihole injection nozzle studied has six holes that are perpendicular to the ambient flue gas flow and are located near
the tip of the nozzle. Large eddy simulation was applied to the turbulent flow and mixing fields to elucidate the mixing mechanism
of the proposed nozzle compared with the single-hole nozzle that is commonly used in the conventional selective catalytic
reduction process. From the results, there exist broader regions of higher turbulent intensities for the multihole nozzle
than for the conventional single-hole nozzle. These regions are well matched with the positions of high vorticity in the near
upstream region of the jet flow issuing from the multiple holes of the nozzle. Consequently, the high turbulent intensities
and vorticity magnitudes lead to intensified mixing between the flue gas and the reducing agent. Hence, the most suitable
molar ratio between NOx and the reducing agent for the catalytic reaction can be easily obtained within a shorter physical
mixing length as a result of the enhanced scalar mixing. Finally, the numerical results were applied to a trial design version
of a multihole nozzle, and this nozzle was experimentally tested to confirm its mixing performance. 相似文献
989.
Leaching behavior of heavy metals from municipal solid waste incineration bottom ash and its geochemical modeling 总被引:1,自引:1,他引:0
Hua Zhang Pin-Jing He Li-Ming Shao Xin-Jie Li 《Journal of Material Cycles and Waste Management》2008,10(1):7-13
With the increase in the number of municipal solid waste incineration (MSWI) plants constructed in China recently, great attention
has been paid to the heavy metal leaching toxicity of MSWI residues. In this study, the effects of various parameters, including
extractant, leaching time, liquid-to-solid ratio, leachate pH, and heavy metal content, on the release properties of Cd, Cr,
Cu, Ni, Pb, and Zn from MSWI bottom ash were investigated. Partial least-squares analysis was employed to highlight the interrelationships
between the factors and response variables. Both experimental research and geochemical modeling using Visual MINTEQ software
were conducted to study the pH-dependent leaching behavior of these metals in fresh and weathered bottom ash, considering
precipitation/dissolution and surface complexation reactions (adsorption by hydrous ferric oxide and amorphous aluminum oxide/hydroxide).
The results showed that leachate pH was the predominant factor influencing heavy metal leachability. The leaching of Cu, Pb,
and Zn was mainly controlled by precipitation/dissolution reactions, whereas surface complexation had some effect on the leaching
of Cr, Cd, and Ni for certain pH ranges. The modeling results aggreed well with the experimental results.
Part of this work was presented at the Fourth International Conference on Combustion, Incineration/Pyrolysis and Emission
Control (i-CIPEC) 相似文献
990.
Markéta Julinová Marie Dvořáčková Jan Kupec Jitka Hubáčková Martina Kopčilová Jaromír Hoffmann Pavol Alexy Anna Nahálková Ida Vašková 《Journal of Polymers and the Environment》2008,16(4):241-249
Improving biodegradability of PVA/starch blends is a reality already documented by a number of works. Admittedly, mechanical
properties of products (for example, tensile strength) are somewhat worse, but suitable composition optimizing or chemical
modifying of starch may eliminate the problem to a large degree. This work is an attempt to find another potential effect
influencing biodegradability, that of technological procedure for producing films from these blends on an extruder. The procedure
with a so-called pre-extrusion step (two-stage) and dry-blend (single-stage) produced blends of slightest differences in achieved
biodegradability (virtually within limits of experimental error) in aerobic (76 vs. 79%) as well as anaerobic breakdown (48
vs. 52%). Conversely, morphological analysis exhibited superior homogeneity of films prepared by the two-stage process; their
tensile strength was also higher. 相似文献