喷雾脱硫时拐形流道内烟气与水雾间传热传质过程研究

本研究在冷态的基础上 ,就单拐形流道内烟气与水雾间传热传质过程进行理论及实验研究。理论上考虑了水雾相的作用 ,提出了对烟气动量方程的修正模型。对拐形流道内烟气单相传热与流动 ,采用K ε湍流模型。两相流动采用两相分离流模型 ,由Lagrange方法求解 ;实验中 ,通过调节多种工况参数 ,结合理论计算最终得出了对烟气脱硫及分离的优化设计     

Sulfide-driven nitrous oxide recovery during the mixotrophic denitrification process

We propose a novel sulfide-driven process to recover N₂O during the traditional denitrification process. The optimum initial sulfide concentration was 120 mg/L, and the N₂O percentage in the gaseous products (N₂O+N₂) was up to 82.9%. Moreover, sulfide involved in denitrification processes could substitute for organic carbon as an electron donor, e.g., 1 g sulfide was equivalent to 0.5-2 g COD when sulfide was oxidized to sulfur and sulfate. The accumulation of N₂O was mainly due to the inhibiting effect of sulfide on nitrous oxide reductase (N₂OR), which was induced by the supply insufficiency of electrons from cytochrome c (cyt c) to N₂OR. When the initial sulfide concentration was 120 mg/L, the N₂OR activity was only 36.8% of its original level. According to the results of cyclic voltammetry, circular dichroism spectra and fluorescence spectra, significant changes in the conformations and protein structures of cyt c were caused by sulfide, and cyt c completely lost its electron transport capacity. This study provides a new concept for N₂O recovery driven by sulfide in the denitrification process. In addition, the findings regarding the mechanism of the inhibition of N₂OR activity have important implications both for reducing emissions of N₂O and recovering N₂O in the sulfide-driven denitrification process.     

贮灰场灰水污染物运移的数值分析

从环境保护的角度出发,针对灰水溶质运移污染地下水的问题,应用混合防渗材料作为防渗层,通过有限元程序模拟贮灰场的实际运行条件,进行了有无防渗层条件下污染物运移的对比计算分析.结果表明,防渗层可有效地减少灰水渗漏量,缩小污染物的长期扩散范围;在灰场底部和内侧设置防渗层是有效的防污染措施.     

气提式内循环膜生物反应器试验研究

针对膜生物反应器存在的膜污染和能耗高的问题，结合气提式内循环和一体式膜生物反应器处理废水的工艺特点，提出圆柱形套筒气提式内循环膜生物反应器。试验结果表明，同等曝气强度和曝气方式下，气提式内循环膜生物反应器中氧传质系数（KLa）高于一般膜生物反应器；膜间水流流速是一般膜生物反应器的1．53～2．44倍，提高了膜面的水力冲刷作用，可减缓膜污染；对反应器膜过滤性能的考察，表明气提式内循环膜生物反应器较一般膜生物反应器有更好的膜过滤性能和抗污染能力。反应器中添加内循环，污泥活性有所下降，但对实际废水的去除效果影响不大，污泥活性较为稳定。     

Stimulants and donors promote megaplasmid pND6-2 horizontal gene transfer in activated sludge

The activated sludge process is characterized by high microbial density and diversity, both of which facilitate antibiotic resistance gene transfer. Many studies have suggested that antibiotic and non-antibiotic drugs at sub-inhibitory concentrations are major inducers of conjugative gene transfer. The self-transmissible plasmid pND6-2 is one of the endogenous plasmids harbored in Pseudomonas putida ND6, which can trigger the transfer of another co-occurring naphthalene-degrading plasmid pND6-1. Therefore, to illustrate the potential influence of stimulants on conjugative transfer of pND6-2, we evaluated the effects of four antibiotics (ampicillin, gentamycin, kanamycin, and tetracycline) and naphthalene, on the conjugal transfer efficiency of pND6-2 by filter-mating experiment. Our findings demonstrated that all stimulants within an optimal dose promoted conjugative transfer of pND6-2 from Pseudomonas putida GKND6 to P. putida KT2440, with tetracycline being the most effective (100 µg/L and 10 µg/L), as it enhanced pND6-2-mediated intra-genera transfer by approximately one hundred-fold. Subsequently, seven AS reactors were constructed with the addition of donors and different stimulants to further elucidate the conjugative behavior of pND6-2 in natural environment. The stimulants positively affected the conjugal process of pND6-2, while donors reshaped the host abundance in the sludge. This was likely because stimulant addition enhanced the expression levels of conjugation transfer-related genes. Furthermore, Blastocatella and Chitinimonas were identified as the potential receptors of plasmid pND6-2, which was not affected by donor types. These findings demonstrate the positive role of sub-inhibitory stimulant treatment on pND6-2 conjugal transfer and the function of donors in re-shaping the host spectrum of pND6-2.     

Greenhouse gas mitigation in developing countries through technology transfer?: a survey of empirical evidence

While greenhouse gas (GHG) emissions are projected to rise primarily in the developing countries, the potential for developing new GHG mitigation technologies exists primarily in the industrialized countries. It is thus important, not only for predictions about future emission paths but also for climate change mitigation policies, to understand how the international diffusion of such technologies takes place and how it affects the energy infrastructure and GHG emissions in developing countries. This paper provides an overview of the channels through which these technologies diffuse and focuses on the empirical evidence pertaining to the effects these technologies have on GHG emissions in developing countries.

USING CONTINGENT VALUATION AND BENEFIT TRANSFER TO EVALUATE WATER SUPPLY IMPROVEMENT BENEFITS1

ABSTRACT: Many water systems in small cities and rural areas throughout the United States are facing water quality and supply problems. These problems are typically not the result of an unexpected event, but are the result of growth trends or decreasing water quality experienced over several years. This analysis uses the contingent valuation and benefit transfer methods to evaluate the willingness to pay for a rural water system in northcentral Montana. Both of the procedures resulted in similar values, ranging from about $4.05 to $7.50 per household per month for urban residents and $5.40 to $11.50 per household per month for rural residents, which is equal to 11 percent to 23 percent of current average water costs. The willingness to pay estimates do not include non-household water users. This analysis shows that useful planning information can be obtained from relatively inexpensive contingent valuation mail survey data and the benefit transfer method as long as the limitations of the data are understood. The willingness to pay for ensuring good quality rural water supplies in the future is likely to be low compared to the costs of extensive diversion and treatment systems. Willingness to pay estimates provide decision makers with information that can be used to avoid building a large water supply system that water users do not want to connect to because of high costs.     

通过外墙窗口喷出火焰问题的研究

用传热学,流体力学等的有关知识,从理论上分析了通过外墙窗口喷出火焰的有关问题,并对这些问题进行了实验研究。结果表明：喷了火焰具有较强的传热的能力,它可能成为建筑火灾由低层向高层蔓延的重要原因。     

几种核素在土壤—生物—人体间的积累和转移

本文对Ｕ，Ｋ，＾１３７Ｃｓ，＾９０Ｓｒ等几种核素在土壤－水稻，土壤－茶叶，土壤－蔬菜之间以及水－鱼间的转移情况进行了研究；并考虑到这些核素含量较高的食品（如茶叶、黄豆）不直接全部食入人体，因此，根据人们的饮茶习惯及豆制品（水豆腐）的加工过程进行模拟，对其向人体转移的参数进行了实验研究。由上述实验结果给出了转移参数及相关方程。     

CONFLICTS IN WATER TRANSFER FROM IRRIGATION TO MUNICIPAL USE IN SEMIARID ENVIRONMENTS1

ABSTRACT: Conflicts caused through development of urban areas in proximity to irrigated agriculture in water-scarce regions can be minimized through the direct urbanization of irrigated lands. This shifts the water supply from one use to another on the same site rather than creating an additional use in an adjoining area. This condition has prevailed in the Phoenix region. In the Tucson region, the municipality is buying and retiring farmland in an adjacent agricultural area, for the purpose of acquiring the water right in order to transfer water to municipal use. This land purchase is necessitated by existing Arizona water law, which ties the water to the land. This method of transfer creates problems concerning how much water can be transferred per acre retired; what to do with the abandoned farmland; inequities to agribusiness and taxing entities; and loss of food crop production which have not been resolved. An alternative to the retirement of farms, applicable in the Tucson region, is to exchange treated municipal wastewater for irrigation water. While this method appears to be the least disruptive, it requires the resolution of certain institutional problems concerned with land and water management method.