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391.
本文通过采用催化法和直燃法两种工艺处理印铁涂装生产的有机废气的工业实践,对设计和运行中的一些要点进行分析和探讨。 相似文献
392.
Thomas A. Clair 《Journal of the American Water Resources Association》1992,28(3):507-515
ABSTRACT: Thirty-five lakes in southern Labrador sampled in 1981 were resampled in 1989 and water chemistry values were compared between visits. Results showed higher pH, specific conductance, acid neutralization capacity, color, and base cations values in 1989, though sulfate, the ion most likely to reflect acid precipitation impacts, did not vary. The major ion changes measured were probably due to natural hydrological variations and not to changes in acid inputs. Results from the 1989 data showed a slight, but significant, decrease in water sulfate concentration trend from western to eastern Labrador, though most values, even in the western portion of the study area, fell close to the values considered “background” by Brakke et at. (1989). Base cation concentrations exceeded those which could be predicted from weathering by carbonic and bicarbonic acid. Assuming that little weathering is generated by acid precipitation in this region, the excess cations measured are probably a result of bedrock dissolution from organic acids generated by plant decomposition. Calculations showed that organic acid effect could be responsible for 9 to 52 percent of total weathering in the study basins. 相似文献
393.
David Pimentel 《Journal of Agricultural and Environmental Ethics》1993,6(1):53-60
The use of organic farming technologies has certain advantages in some situations and for certain crops such as maize; however, with other crops such as vegetables and fruits, yields under organic production may be substantially reduced compared with conventional production. In most cases, the use of organic technologies requires higher labor inputs than conventional technologies. Some major advantages of organic production are the conservation of soil and water resources and the effective recycling of livestock wastes when they are available. 相似文献
394.
刘向葵 《中国环境管理干部学院学报》1999,(4)
用城市生活垃圾经好氧高温制成堆肥,并向其中加入无机化肥和微量元素添加剂可制成有机复合肥。本文简要阐述了好氧高温堆肥的生产工艺,推荐了用垃圾生产有机复合肥的两类配方。 相似文献
395.
Roland Bunch 《Environment, Development and Sustainability》1999,1(3-4):219-233
A study of the impact of two agroecological development programs in central America was conducted in 1994, five years and fifteen years after the programmes had ended. Yields of maize and beans being achieved by those farmers involved in each program were, on the average, more than seven times the yields being achieved at the time of program initiation. Increases in yields and incomes were achieved through the use of a large number of innovations, involving especially soil retention measures, purchased organic matter, intercropped green manure/cover crops, natural pest control, crop diversification and crop rotations. Use of chemical fertilizer was reduced, herbicides avoided almost entirely, and several substitutes for pesticides are now used. These technologies, plus more recent innovations such as microscale water harvesting and precision planting, should enable small farmers around the world to increase productivity enough that the world can avoid major hunger over the next 30 years, without increasing substantially, if at all, the world's use of chemical inputs. 相似文献
396.
Kylefors K 《Journal of environmental management》2003,68(4):367-376
Landfills generate emissions in the form of gas and leachate. The emissions are often measured within monitoring programmes. It is likely that the requirements of such monitoring programmes can be extended in the future, particularly in light of the increased interest in specific organic substances. Multivariate data analyses (MVDA) have been used to evaluate the possibility of predicting the content of specific organic substances from more common analyses. The results indicate that this is possible for a specific leachate. MVDA can also be used to reduce the number of analyses performed within existing monitoring programmes while retaining information about all the variables formerly included in the programmes. 相似文献
397.
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399.
Frank J. Triska John H. Duff Richard W. Sheibley Alan P. Jackman Ronald J. Avanzino 《Journal of the American Water Resources Association》2007,43(1):60-71
Abstract: Dissolved inorganic nitrogen (DIN) retention‐transport through a headwater catchment was synthesized from studies encompassing four distinct hydrologic zones of the Shingobee River Headwaters near the origin of the Mississippi River. The hydrologic zones included: (1) hillslope ground water (ridge to bankside riparian); (2) alluvial riparian ground water; (3) ground water discharged through subchannel sediments (hyporheic zone); and (4) channel surface water. During subsurface hillslope transport through Zone 1, DIN, primarily nitrate, decreased from ~3 mg‐N/l to <0.1 mg‐N/l. Ambient seasonal nitrate:chloride ratios in hillslope flow paths indicated both dilution and biotic processing caused nitrate loss. Biologically available organic carbon controlled biotic nitrate retention during hillslope transport. In the alluvial riparian zone (Zone 2) biologically available organic carbon controlled nitrate depletion although processing of both ambient and amended nitrate was faster during the summer than winter. In the hyporheic zone (Zone 3) and stream surface water (Zone 4) DIN retention was primarily controlled by temperature. Perfusion core studies using hyporheic sediment indicated sufficient organic carbon in bed sediments to retain ground water DIN via coupled nitrification‐denitrification. Numerical simulations of seasonal hyporheic sediment nitrification‐denitrification rates from perfusion cores adequately predicted surface water ammonium but not nitrate when compared to 5 years of monthly field data (1989‐93). Mass balance studies in stream surface water indicated proportionally higher summer than winter N retention. Watershed DIN retention was effective during summer under the current land use of intermittently grazed pasture. However, more intensive land use such as row crop agriculture would decrease nitrate retention efficiency and increase loads to surface water. Understanding DIN retention capacity throughout the system, including special channel features such as sloughs, wetlands and floodplains that provide surface water‐ground water connectivity, will be required to develop effective nitrate management strategies. 相似文献
400.
Naoya Tachibana Kenya Nagasawa Binhui Wang Kazuki Nishiya Masami Fukushima Hikari Kanno Takuro Shinano Keiki Okazaki 《Chemosphere》2013
The effects of water-extractable organic matter (WEOM) from compost-like materials on peroxidative stress were investigated for hydroponic culture of barley exposed to Cd. In the presence of WEOM, lipoxygenase activity and malondialdehyde, indices of peroxidative stress in barley, were significantly reduced, compared to those with Cd alone (5 μM) for a 30-d culture (p < 0.05). In addition, Cd uptake in the presence of WEOM samples was significantly lower than that in their absence (p < 0.05). These results indicate that the addition of WEOM can be effective in mitigating the peroxidative stress in barley exposed to Cd. Of the total Cd in the solution, 7–8% was complexed with WEOM, indicating that the complexation of Cd with WEOM is a minor factor in reducing Cd-induced stress in barley. The WEOM sample was purified by cation-exchange column and ultrafiltration to remove the nutrient minerals, such as Ca, Mg and Fe. When the purified WEOM was employed for hydroponic culture in the presence of Cd, significant decreases in peroxidative stress and Cd uptake were observed (p < 0.05). These results show that the organic components in WEOM contribute to the mitigation of peroxidative stress in barley exposed to Cd. 相似文献