氨精制产品质量影响因素及改进措施

阐述了浓氨水循环洗涤法脱硫工艺原理，原则流程，开工、运行过程中存在的问题及解决方案，影响液氨产品质量因素及采取的措施，以及对原林源石化公司含硫法水汽提-氨精制系统不足提出的改进建议。     

Dissolved Ions of Trace and Major Elements and in Suspended Sediments in the Nile, Egypt

Dissolved ions and suspended participates from twelve water samples from Sohag (different localities) and Aswan (behind and below the High Dam) areas were collected along the River Nile, upper Egypt, which is at present affected seriously by pressure of population, intense industrial and agricultural activities, and atmospheric fallout. Eighteen trace and nine major ions in solution and fourteen metals in suspension were analyzed to establish whether elements are of anthropogenic or natural origin. Results of this study show that the Nile water was contaminated with high concentrations of dissolved lead, and with copper, nickel and mercury to a lesser extent, suggesting that these contaminants are generated from anthropogenic activities. the other dissolved ions in the Nile are of natural origin because their metal concentrations fall within the range of the normal background and average world dissolved values for inland waters. Results show that the usual constituents of suspended particulates in the Nile seem to be some metals (Cu and Zn) adsorbed on iron and manganese oxide/hydroxide. the results also reveal that most trace and major metal particulates increase from south to north due to activities associated with the dense population living along the Nile banks. No significant differences were observed between the chemical composition of trace and major elements taken on the east and west river Nile banks.     

MANAGEMENT OF WATER QUALITY IN RELEASES FROM SOUTHWESTERN IMPOUNDMENTS1

ABSTRACT. The objective of this investigation was to determine the selectivity of withdrawal which is possible in southwestern reservoirs. Two stratified flow solutions were examined to test their applicability under field conditions. Although both appeared capable of accurate prediction of the outflow velocity profile, the Bohan-Grace solution, which required less input data, was utilized to predict the chemical constituents of single and simultaneous releases from several southwestern impoundments. Prediction of outflow water quality was within fifteen percent for southwestern reservoirs as shallow as fifty-five feet. The withdrawal layer thickness for the subject Texas impoundments included the entire hypolimnion or epilmnion depending on outlet location. The sensitivity of the velocity profile to seasonal changes, reservoir discharge rate and withdrawal port dimensions also is illustrated.     

论水稻土肥力进化与土壤质量——以太湖地区为例

太湖地区是我国古老农业区之一。在六七千年之前先民已开始种植水稻 ,随着耕作培肥措施不断加强 ,与土壤肥力进化同步伴随着耕作轮作制的不断演进 ,由轮荒———沤田———水旱轮作———三熟制的变化 ,土壤基础肥力稳步提高 ,稻麦单位面积产量逐年上升。该区水稻土历经数千年的耕肥与平田整地等人为活动 ,在起源土壤背景上发育成五类水稻土 ,这五类水稻土经过培肥改良均达到水旱轮作高产稳产阶段 ,尽管地力上还存在不同程度的差异 ,这不能不说是人为定向培育的成果。在一般情况下 ,土壤质量是由土壤肥力决定的 ,基础肥力高低是农业生产优质高产低耗的关键 ,在评价土壤质量时必需首先予以关注。当然 ,随着工业的发展 ,土壤污染所波及的农产品超标问题 ,也应在评价土壤质量时予以关注 ,并作为评价因素在综合评价体系中占有应有的份量     

浮桥河水库的营养状况与水质调控措施

浮桥河水库总磷含量、浮游植物的初级生产力和浮游动物的生物量有逐渐增加的趋势。上、中、下游水体的总磷含量分别为 0 .0 72mg/L、0 .0 6 6mg/L和 0 .0 4 4mg/L ;浮游植物的生物量分别为9.2 8mg/L、6 .51mg/L和 3.37mg/L。夏季和秋季上游部分区域伴有大面积的“水华” ,优势种类主要为微囊藻。浮游植物水柱日生产量分别为 2 .80 gO2 /m2 .d、2 .78gO2 /m2 .d和 2 .36 gO2 /m2 .d ;浮游动物的生物量分别为 2 .52mg/L、1.2 5mg/L和 1.2 2mg/L。浮桥河水库有富营养化的趋势且上游已经富营养化。导致富营养化的原因主要是外源营养物输入量的增加、大库鲢鳙放养比例失调、上游滤食性网箱放养结构的不合理和食鱼性鱼类的过度捕捞。建议在保持现有鳙放养量的前提下增大大库鲢的放养量和网箱内鲢鱼种的放养量、减少食鱼性鱼类的捕捞量、减少外源营养物的输入以控制水库的富营养化。     

A critical review of the water quality classification system in Turkey: A case study on Meric Basin

An 11-year period of water quality data, collected by the Directorate of Sate Water Works of Turkey are thoroughly analyzed for the purpose of implementing water quality classes to water resources in the Meric Basin, located on the European land mass of Turkey. Water quality parameters are divided into four groups as physical, organic, inorganic, and bacteriological. The quality class of each group is evaluated by taking into account the poorest quality of any parameter in the group, after which a quality rank is assigned to the sampling station and the waterbody in question. This method of water quality classification imposed by the Turkish Water Quality Act, is then criticized with respect to a statistical approach.     

TIMBER MANAGEMENT INFLUENCES ON AQUATIC ECOSYSTEMS AND RECOMMENDATIONS FOR FUTURE RESEARCH1

ABSTRACT: Recent watershed research indicates that many timber management practices have profound effects on the water quality of small headwater streams. These streams often support fisheries of high value. Current knowledge seems to indicate that a definite potential exists for a symbiotic relationship between timber and fisheries management. Maximum development of both resources is attainable only if further research efforts recognize the mutually benefiting aspects of these heretofore separate disciplines. Future research should carefully examine the complex interrelationships between small headwater aquatic ecosystems and the riparian forest environment.     

Differential leaching of nutrients from soluble vs. controlled-release fertilizers

Extremely sandy soils and poorly distributed high annual rainfall in the state of Florida contribute to significant leaching losses of nutrients from routine fertilization practices. A leaching column experiment was conducted to evaluate the leaching losses of nutrients when using currently available N, P, K blend fertilizers for young citrus tree fertilization. Fertilizer blends included NH₄NO₃, Ca(NO₃)₂, IBDU, IBDU plus Escote, Nutralene, Osmocote, and Meister. Following leaching of 1000 ml of water through soil columns, which simulates leaching conditions with 26 cm of rainfall, the amount of NO₃ and NH₄ recovered in the leachate from soil columns amended with an NH₄NO₃ blend accounted for 37% and 88% of the respective nutrients contained in the quantity of blend per column. The corresponding values for soil columns amended with a Ca(NO₃)₂ blend were 48% and 100%. Leraching losses of both NO₃ (<3%) and NH₄ (<4%) were drastically decreased when using controlled-release fertilizers. The recoveries of P and K in 1000 ml of leachate were 1.3% and 8%, respectively, of the nutrients added as Osmocote, which contained coated P and K sources. In the case of the rest of fertilizer blends, the recoveries of P and K in 1000 ml of leachate were as high as 52%–100% and 28%–100%, respectively. Therefore, controlled-release technology offers an important capability for minimizing leaching losses of nutrients.     

县域耕地总量动态平衡规划模式的构建－－以江苏省启东市为例

本文在界定耕地总量动态平衡是由耕地数量、耕地质量和耕地生态环境三者组成的整体平衡的基础之上 ,对耕地总量的评价方法进行了初步研究 ,并以启东市为例 ,构建了耕地生产力总量动态平衡规划模式。     

Environmental issues in Sweden 1973–1989: Science and policy

The aim of this study is to analyze the environmental agenda in Sweden during the last two decades. A content analysis was made of all articles in a Swedish journal,Miljö-Aktuellt. Further, to elucidate the evolutionary process of problem formulation and reformulation, two cases were investigated, dealing with the impact of plant nutrients and mercury on surface water quality. The transport of heavy metals is an essential component of the ecological process and problem of acidification, and similarly, plant nutrients are part of the concept of eutrophication. Two concepts, the research cycle and the policy cycle, are tentatively applied to the conceptualizations of acidification and eutrophication. Additional data for the latter part of the study is supplied from parliamentary motions during 1973–1989. The substance/media focus of the 1970s was connected to a point-source abatement strategy, which mainly aimed at removing negative effects at a local level. The development of a national preventive strategy is traced in problem formulations related to “processes” going on in the technosphere: wastes, noise, energy production, traffic, and toxic substances. This period lasted from the mid-1970s to the mid-1980s, and the need for improved resource management as a means to control environmental problems has been a generally accepted idea. However, this does not mean that measures actually taken are sufficient in a material balance perspective. Further, in the 1980s there was a strong emphasis upon processes in the ecosphere. This focus also implies source-related policies. To a certain extent, the remedies are within the scope of national capabilities, but the international dimension is becoming increasingly important. Scientific proofs of resource and environment degradation are essential to induce political action and to stimulate international cooperation. From this study, however, it is not possible to assess the existence of any particular policy-triggering information.