新型错位板对静电除尘器流场影响的数值模拟

为降低现有除尘器的改造成本,提高微细粉尘的收集效率,在现有除尘器的基础上,对阳极板排布方式进行调整,设计错位排布方式,最大化地利用原有除尘器的资源,以最小的改造成本,达到较满意的除尘效果.利用目前应用广泛的FLUENT仿真软件进行数值模拟,观察分析了其电势分布和气流分布.数值模拟结果表明:当主流风速小于0.5 m·s-...     

戊二醛对紫色非硫光合细菌脱氢酶活力的影响

探讨微生物细胞对戊二醛毒性的耐受能力及应用条件的适宜范围,可为废水处理中固定化细胞的应用提供实验基础和理论依据。以紫色非硫光合细菌（PSB）为例,直接用戊二醛作用于细胞,在不同pH值、温度、戊二醛浓度、反应时间等条件下研究戊二醛对PSB脱氢酶活力的影响。结果表明：戊二醛对PSB脱氢酶活力影响的主要限制因素为戊二醛浓度和反应时间。当戊二醛浓度为0.5～1.0％,反应时间为1～2h时,PSB脱氢酶活力回收可达83％以上;PSB细胞经戊二醛处理后,热稳定性增强,pH稳定性无明显变化;并比较出热带假丝酵母菌和PSB对戊二醛的毒性耐受能力大于大肠埃希氏杆菌和芽孢杆菌yol。     

废水稳定塘底泥蓄积规律的分析

通过对底泥来源及组成的分析,认为底泥由可生物降解和不可生物降解两部分组成,并对每部分的蓄积规律及影响因素进行了分析研究,在此基础上建立了稳定塘底泥蓄积公式。根据该公式可得出:①底泥中不可生物降解部分的蓄积与塘运行时间成正比;②可生物降解部分的蓄积存在一个极限值;⑨塘底泥的蓄积与进水水质、水量及塘的运行状况密切相关,同时还受温度的影响。     

清除废气中VOCs的流向变换催化燃烧技术进展

一、引　　言环境恶化严重地威胁人类的生存和社会的可持续发展 ,是当前全世界共同面临的一个重大问题。作为空气污染的主要来源之一 ,易挥发有机物 (ＶＯＣｓ)不仅是一次污染源而且还可能造成光化学烟雾等二次污染[1 ] 。因此 ,控制大气中挥发性有机物非常重要。美国 1 990年开始实施的清洁空气法修正案要求在其后的九年内使大气中有毒化学品的排放量减少 90 % ,其中 70 %为易挥发有机物 (ＶＯＣｓ) ,其他发达国家也都围绕改善生态环境和有效利用资源的战略性要求采取了相应的措施。尤其是投入了大量的人力、物力 ,致力于控制空气中挥发性…     

草场蝗虫的种群密度与受害程度及经济阈值的探讨

以野外实测为基础,应用统计学方法,探讨了天山北坡中段草场蝗虫虫口密度与草场产量的关系,并依此建立了半荒漠草场意大利蝗虫危害防治的经济阈值,即69头／m23令前意大利蝗虫。     

A-B工艺处理以高浓度有机废水为主的城市污水

A B工艺的进水主要以高浓度有机废水为主 ,溶解性的CODCr成分高且难以生物降解 ,高有机负荷和极端pH的冲击经常发生。根据进水水质的特点并结合A B工艺独特的优越性 ,合理地控制A段的运行参数 ,最大限度地挖掘A B工艺的潜力 ,保证A段的处理效果和出水的稳定性 ,为B段稳定运行创造好的条件。     

痕量壬基酚及相关化合物的样品预处理和测定

对近年来环境样品中痕量内分泌干扰物壬基酚及相关化合物的分离富集方法和测定技术的研究进展进行了综合评述。重点讨论了索氏提取、液液萃取、液膜分离、回流萃取、固相萃取、固相微萃取、超临界流体萃取、超声提取八种样品预处理方法和气相色谱质谱联用、高效液相色谱两种测定方法,而且针对以上方面提出了尚需进一步研究的问题。     

MRIO model-based study on water nitrogen pollution transfer embodied in international trade

This study uses the global pollutant emission databases and global input–output model in 2015 to calculate the impact of international trade on global water nitrogen emission patterns, based on considering the total amount of pollutant transfer and pollutant emission intensity of trade flows The main conclusions are as follows: (1) There are always a large amount of water nitrogen emissions transferring from developed economies to developing economies embodied in their bilateral trade activities. Small amount of transfers are of some areas with similar endowments of agricultural resources or long distances. (2) In 2015, the net import of water nitrogen pollution embodied in China’s trade was 160,000 tons, accounting for 2.72% of the global water nitrogen imports. The sharp increases in cereal imports, together with high food storage as well as high pollution intensity embedded in trade are the main reason. It is recommended that through applying alleviations such as agricultural machinery assistance and technical training to accelerate the transfer and spread of agricultural technology in Africa, Asia, and other regions, thus helping increase agricultural production productivity in underdeveloped areas and reducing the pollution intensity embodied in trade flows from underdeveloped areas to developed areas.     

Estimating Root Zone Soil Moisture at Continental Scale Using Neural Networks

This study investigates the feasibility of artificial neural networks (ANNs) to retrieve root zone soil moisture (RZSM) at the depths of 20 cm (SM20) and 50 cm (SM50) at a continental scale, using surface information. To train the ANNs to capture interactions between land surface and various climatic patterns, data of 557 stations over the continental United States were collected. A sensitivity analysis revealed that the ANNs were able to identify input variables that directly affect the water and energy balance in root zone. The data important for RZSM retrieval in a large area included soil texture, surface soil moisture, and the cumulative values of air temperature, surface soil temperature, rainfall, and snowfall. The results showed that the ANNs had high skill in retrieving SM20 with a correlation coefficient above 0.7 in most cases, but were less effective at estimating SM50. The comparison of the ANNs showed that using soil texture data improved the model performance, especially for the estimation of SM50. It was demonstrated that the ANNs had high flexibility for applications in different climatic regions. The method was used to generate RZSM in North America using Soil Moisture and Ocean Salinity (SMOS) soil moisture data, and achieved a spatial soil moisture pattern comparable to that of Global Land Data Assimilation System Noah model with comparable performance to the SMOS surface soil moisture retrievals. The models can be efficient alternatives to assimilate remote sensing soil moisture data for shallow RZSM retrieval.     

固定化优势菌种处理NH3和H2S恶臭气体

用海藻酸钠作包埋剂固定优势菌种(枯草芽孢杆菌、白曲霉菌、葡萄球菌)处理NH3和H2S。考察了气体流量、NH3和H2S气体浓度、循环液喷淋量对NH3和H2S去除效果的影响。固定化生物滴滤反应器最佳运行条件为:气体流量1.0m3/h、循环液喷淋量8.88L/h、进气H2S质量浓度低于51.85mg/m3、进气NH3质量浓度低于57.21mg/m3。处理NH3和H2S的最大容积负荷分别为634.1g/(m3·d)和699.6g/(m3·d)。处理后出气中的NH3和H2S的质量浓度分别达到GB14554—93《恶臭污染物排放标准》中的一级排放标准和二级排放标准。