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81.
82.
以从我国最大的石油污水灌区之一——沈抚灌区污染土壤分离到的以芘为惟一碳源、能源生长的高效降解菌株ZQ5为实验材料,通过对菌株ZQ5培养条件的优化,以及采用摇瓶振荡培养方法测定菌株ZQ5对不同浓度芘的降解率,表明:菌株ZQ5在30℃振荡培养16 d后对150 mg/L芘的降解率为90.31%。通过模拟稻田施用N、P和K肥等的土壤环境,探索了无机营养元素对降解菌ZQ5降解能力的影响,发现土壤中混合加入N、P和K无机营养元素的降解率能达到82%以上,比单加某种营养元素对降解菌ZQ5的降解效果好。本研究结果可以指导稻田PAHs的原位生物修复。 相似文献
83.
Bai M Zhang Z Tian Y Bai M 《Journal of the Air & Waste Management Association (1995)》2012,62(4):393-397
A new method for rapidly eliminating pathogenic microorganisms in large air space using spraying *OH radicals is presented in this paper With a physical method of strong electric-field discharge, large numbers of *OH radicals were produced by the oxygen activated particles of O2+, O(1D), O(3P), etc., and the introducing reagent HO2-. The gram-positive bacteria Bacillus subtilis, the gram-negative bacteria Serratia marcescens, and Bacillus spores were used for the eliminating experiments. Results show that the different microorganisms were rapidly killed by *OH radicals with a concentration of 0.8 mg/L and spraying density of 21 microL/m2 within 4 sec. Cell morphological changes were also observed under microscope. The cells of B. subtilis and Bacillus spores in their cellular wall, cellular membrane, or cell protoplasm were greatly destroyed when being exposed to a killing dosage of *OH radicals. 相似文献
84.
Chang YC Bai H Chiang HS Karthik M Li SN Hsu JN Shih HY 《Journal of the Air & Waste Management Association (1995)》2012,62(7):838-845
The mesostructured materials MCM-41 and SBA-15 were studied as possible supports of bromocresol green (BG) dye impregnation for the ammonia gas detection because of their large surface area, high regenerative property, and high thermal stability. X-ray diffraction, transmission electron microscopy, scanning electron microscope, and N2 adsorption analysis were used to characterize the prepared materials. These materials could sense ammonia via visible color change from yellowish-orange to blue color. The color change process of the nanostructured materials was fully reversible during 10 cyclic tests. The results indicated that the ammonia absorption responses of the two nanostructured materials were both very sensitive, and high linear correlation and high precision were achieved. As the gaseous ammonia concentrations were 50 and 5 ppmv, the response times for the SBA-15/BG were only 1 and 5 min, respectively. Moreover the BG dye-impregnated SBA-15 was less affected by the variation in the relative humidity. It also had faster response for the detection of NH3, as well as lower manufacturing price as compared to that of the dye-impregnated MCM-41. Such feature enables SBA-15/BG to be a very promising material for the detection of ammonia gas. 相似文献
85.
为了研究厌氧折流板反应器在常温下的启动情况,在22.5~30.2℃条件下,对不加填料的5隔室厌氧折流板反应器和加填料的4隔室复合式厌氧折流板反应器同步进行了启动实验。实验用水为高浓度淀粉废水,两反应器采用相同的启动策略,即梯度增加进水COD浓度与降低水力停留时间相结合的方式。两反应器有效容积均为47.8 L,启动初始负荷为0.6 kg COD/(m3.d),逐渐增加到10 kg COD/(m3.d)。实验表明,经过6个阶段87 d的运行,反应器启动完成,并成功培养出颗粒污泥,两反应器对COD的去除率都能达到85%以上。在启动过程中两反应器对COD的去除效率相近。 相似文献
86.
87.
Hongfang Lu Yu Bai Hai Ren Daniel E. Campbell 《Journal of environmental management》2010,91(12):2727-2735
China is the largest rice producing and consuming country in the world, but rice production has given way to the production of vegetables during the past twenty years. The government has been trying to stop this land-use conversion and increase the area in rice-vegetable rotation. Important questions that must be answered to determine what strategy is best for society are, “What is the reason behind this conversion?”; “Which system is more productive and which is more sustainable?”; and “How can economic policy be used to adjust the pattern of farmland use to attain sustainable development?” To answer these questions, a combined evaluation of these agricultural production systems was done using emergy, energy and economic methods. An economic analysis clearly showed that the reason for this conversion was simply that the economic output/input ratio and the benefit density of the vegetable production system were greater than that of rice. However, both energy and emergy evaluations showed that long-term rice was the best choice for sustainable development, followed by rotation systems. The current price of rice is lower than the em-value of rice produced from the long-term rice system, but higher than that of rice produced from the rotation system. Scenario analysis showed that if the government increases the price of rice to the em-value of rice produced from the long-term rice system, US$0.4/kg, and takes the value of soil organic matter into account, the economic output/input ratios of both the rice and rotation systems will be higher than that of the vegetable system. The three methods, energy, emergy and economics, are different but complementary, each revealing a different aspect of the same system. Their combined use shows not only the reasons behind a system’s current state or condition, but also the way to adjust these systems to move toward more sustainable states. 相似文献
88.
着重研究了不同紫外灯光源和照射时间条件下,TiO2光催化(PCO)对微滤去除腐殖酸过程中的膜污染控制,并探讨了膜污染的控制机理。研究结果表明,TiO2光催化能有效提高微滤对腐殖酸的去除,同时降低膜通量的下降,起到有效控制膜污染的作用。进一步的实验分析表明,TiO2光催化控制膜污染的主要机理在于将腐殖酸降解为易于被TiO2吸附的小分子量物质,吸附腐殖酸降解产物后的TiO2聚合颗粒粒径增大,易于在膜表面形成更为松散的沉积层,并使膜污染从以膜孔堵塞和沉积层污染为主转化为以沉积层污染为主的可逆性污染。 相似文献
89.
Mark Hixson Abdullah Mahmud Jianlin Hu Song Bai Debbie A. Niemeier Susan L. Handy Shengyi Gao Jay R. Lund Dana Coe Sullivan Michael J. Kleeman 《Atmospheric environment (Oxford, England : 1994)》2010,44(4):552-562
Future air pollution emissions in the year 2030 were estimated for the San Joaquin Valley (SJV) in central California using a combined system of land use, mobile, off-road, stationary, area, and biogenic emissions models. Four scenarios were developed that use different assumptions about the density of development and level of investment in transportation infrastructure to accommodate the expected doubling of the SJV population in the next 20 years. Scenario 1 reflects current land-use patterns and infrastructure while scenario 2 encouraged compact urban footprints including redevelopment of existing urban centers and investments in transit. Scenario 3 allowed sprawling development in the SJV with reduced population density in existing urban centers and construction of all planned freeways. Scenario 4 followed currently adopted land use and transportation plans for the SJV. The air quality resulting from these urban development scenarios was evaluated using meteorology from a winter stagnation event that occurred on December 15th, 2000 to January 7th 2001. Predicted base-case PM2.5 mass concentrations within the region exceeded 35 μg m?3 over the 22-day episode. Compact growth reduced the PM2.5 concentrations by ~1 μg m?3 relative to the base-case over most of the SJV with the exception of increases (~1 μg m?3) in urban centers driven by increased concentrations of elemental carbon (EC) and organic carbon (OC). Low-density development increased the PM2.5 concentrations by 1–4 μg m?3 over most of the region, with decreases (0.5–2 μg m?3) around urban areas. Population-weighted average PM2.5 concentrations were very similar for all development scenarios ranging between 16 and 17.4 μg m?3. Exposure to primary PM components such as EC and OC increased 10–15% for high density development scenarios and decreased by 11–19% for low-density scenarios. Patterns for secondary PM components such as nitrate and ammonium ion were almost exactly reversed, with a 10% increase under low-density development and a 5% decrease under high density development. The increased human exposure to primary pollutants such as EC and OC could be predicted using a simplified analysis of population-weighted primary emissions. Regional planning agencies should develop thresholds of population-weighted primary emissions exposure to guide the development of growth plans. This metric will allow them to actively reduce the potential negative impacts of compact growth while preserving the benefits. 相似文献
90.
着重研究了不同紫外灯光源和照射时间条件下,TiO_2光催化(PCO)对微滤去除腐殖酸过程中的膜污染控制,并探讨了膜污染的控制机理。研究结果表明,TiO_2光催化能有效提高微滤对腐殖酸的去除,同时降低膜通量的下降,起到有效控制膜污染的作用。进一步的实验分析表明,TiO_2光催化控制膜污染的主要机理在于将腐殖酸降解为易于被TiO_2吸附的小分子量物质,吸附腐殖酸降解产物后的TiO_2聚合颗粒粒径增大,易于在膜表面形成更为松散的沉积层,并使膜污染从以膜孔堵塞和沉积层污染为主转化为以沉积层污染为主的可逆性污染。 相似文献