高炉出铁场“电改袋”技术研究与工程示范

20世纪,在炼铁生产过程中,高炉出铁场的除尘基本采用的是电除尘器技术。随着环境要求的提高,许多炼铁厂将电除尘改为布袋除尘——电改袋。"电改袋"通常要利用原有的电除尘器壳体,只改变其内部结构,从而也改变了原除尘器内气流流向。为了预测"电改袋"后各区域气流流向,文章基于CFX商用流体力学计算软件,对除尘器"电改袋"后的气流进行了速度场模拟。模拟研究结果表明:从前到后,各滤室上行风速逐渐增大。对于4滤室的袋式除尘器,第四滤室风量比第一滤室风速大3倍以上。为了克服风量不均衡问题,采用可调式斜向挡板风量分配新工艺,从而对提高袋式除尘器的收尘性能,指导"电改袋"的工程实践具有重要意义。     

自动增氧型潜流人工湿地处理农村生活污水的研究

采用人工配水模拟太湖地区农村生活污水水质,利用改进的自动增氧型潜流人工湿地对其进行处理,结果表明:COD、NH4 -N、TP进水浓度分别在132.4～392.6mg·L-1、21.58～50.26mg·L-1、3.60～13.17mg·L-1范围内变化时,COD、NH4 -N、TP的去除负荷随着进水浓度的升高而增大,其最高去除负荷分别为226.38 kg·d-1·hm-2、44.40 kg·d-1·hm-2、10.44 kg·d-1·hm-2,相应的去除率为89.45%、88.93%、90.25%,且系统有较强的抗冲击负荷能力.     

改良型DE氧化沟工艺的除磷脱氮分析

新都污水处理厂所采取的改良型DE氧化沟经工程实践证明效果较好,针对该处理工艺流程和DE氧化沟自身的改进进行了分析,总结了为强化脱氮除磷进行改良的经验。     

不同植物的表面流人工湿地系统对污染物的去除效果

通过对4种不同植物的表面流人工湿地系统处理新沂河河水的中试研究表明,在CODMn和NH 4-N进水浓度相同条件下,香蒲湿地系统出水CODMn平均浓度最低,仅为13.44 mg/L;美人蕉湿地系统出水NH 4-N平均浓度最低,仅为1.75 mg/L;香蒲和美人蕉湿地系统对CODMn的平均去除率都达到40%以上,而千屈菜和水葱湿地系统都低于30%;美人蕉、香蒲和千屈菜湿地系统对NH 4-N的平均去除率都达到65%以上,而水葱系统则低于60%.综合比较,香蒲和美人蕉湿地系统的净化能力较强.4种植物中水葱耐淹能力最强,完全淹水22 d以上依然生长良好;千屈菜耐淹能力最弱,完全淹水7 d后就开始枯萎,17 d后地上、地下部分全部死亡.     

Application of Eichhornia crassipes and Pistia stratiotes for treatment of urban sewage in Israel

The effectiveness of sewage purification by aquatic plants, such as water hyacinth (Eichhornia crassipes) and water lettuce (Pistia stratiotes), was tested on laboratory and pilot scales. Cascade and semi-continuous pilot experiments verified that the plants are capable of decreasing all tested indicators of water quality to levels that permit the use of the purified water for irrigation of tree crops. This applies to biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), and turbidity. The laboratory-scale tests confirm the capacity of the plants to reach and hold reasonably low levels of BOD (5-7 mg L(-1)) and COD (40-50 mg L(-1)) and very low levels of TSS (3-5 mg L(-1)) and turbidity (1-2 NTU). In the experimental pilot setup, with circulation, COD decreased from 460 to 100 mg L(-1) after 2.5-4 days of treatment, while 6-7 days were required to this end without circulation. This doubled the active pond area and provided a two-level hydraulic loading (8 and 12 L min(-1)) with circulation that proved to be effective during the summer as well as the winter season. The outflow concentrations were 50-85 mg L(-1) of COD and 4-6 mg L(-1) of BOD. The results show that the use of this free water surface flow system (FWS) and its low maintenance system for treatment of urban and agricultural sewage is a viable option.     

Incomplete mixing in a small, urban stream

Conservative solute tracer experiments were conducted in Indian Creek, a small urban stream located in Philadelphia, Pennsylvania, USA. Estimated flow rates were between 46 Ls(-1) and 81 Ls(-1), average stream width was 5.5m and average stream depth was 0.2m. Given these dimensions, most researchers would think it reasonable to assume that the stream is completely mixed vertically and horizontally. However, we found that the stream was not vertically completely mixed in a 1.0m deep, 30 m long pool. The limited mixing was demonstrated by the vertical stratification of a tracer cloud which was completely mixed both laterally and vertically across the stream prior to entering the pool. We suggest that the cause of limited mixing is due to a balance between groundwater inflow and transverse dispersion at the cross-section. We show that the unsupported assumption of complete mixing may result in a wide range, and thus increased uncertainty, of the values of stream flow and longitudinal dispersion coefficient estimated from these data. We conclude that the assumption of complete mixing and one-dimensional modeling must be checked against actual field conditions, even in small streams.     

Dynamic phosphorus budget for lake-watershed ecosystems

Lake eutrophication caused by excess phosphorus （P） loading from point sources （PS） and nonpoint sources （NPS） is a persistent and serious ecological problem in China. A phosphorus budget, based on material flow analysis（MFA） and system dynamic （SD）, is proposed and applied for the agriculture-dominated Qionghai Lake watershed located in southwestern China. The MFA-SD approach will not only cover the transporting process of P in the lake-watershed ecosystems, but also can deal with the changes of P budget due to the dynamics of watershed. P inflows include the fertilizer for agricultural croplands, soil losses, domestic sewage discharges, and the atmospheric disposition such as precipitation and dust sinking. Outflows are consisted of hydrologic export, water resources development, fishery and aquatic plants harvesting. The internal P recycling processes are also considered in this paper. From 1988 to 2015, the total P inflows for Lake Qionghai are in a rapid increase from 35.65 to 78.73 t/a, which results in the rising of P concentration in the lake. Among the total P load 2015, agricultural loss and domestic sewage account for 70.60% and 17.27% respectively, directly related to the rapid social-economic development and the swift urbanization. Future management programs designed to reduce P inputs must be put into practices in the coming years to ensure the ecosystem health in the watershed.     

花山岩画渗水病害机理及环境治理对策

根据花山岩画区的水文地质与工程地质条件,分析了渗水病害的类型、危害及其形成机理。按水在崖壁上的运移方式将花山岩画的渗水病害分为裂隙渗水和面流水,着重分析了它们各自的危害和机理,提出了防渗堵漏、建立地表排水系统、修建立壁遮挡檐等防治对策。     

基于陶瓷行业脱硫塔管束除雾器流速调控装置的设计研究

目的 针对陶瓷行业烟气"超净排放"须达到的标准(颗粒物浓度小于5 mg/Nm3)要求,创新设计管束除雾器流速调控装置结构.方法 在脱硫塔管束除雾器流速调控装置的出口末端均匀布置多组调节阀门,根据实际工况烟气量通过调节延伸在塔外的调节杆控制阀门启闭的数量,进而控制通过管束除雾器的总烟气量,实现单筒管束除雾器的筒内流速在设...     

OH自由基与溴乙烷反应动力学和大气中存留寿命

溴代烷烃是破坏臭氧层的重要物质,用放电流动－共振荧光技术,测定ＯＨ自由基与Ｃ２Ｈ５Ｂｒ在２９７－３６９Ｋ温度范围的反应速率常数,求得其阿仑尼乌斯公式,并根据对流层的平均温度２２７Ｋ下求是ＯＨ自由基与溴乙烷反应速率常数（Ｋ）值,算出共在对流层的寿命为０．１６８ａ这将提供这类化合物使用否的重要科学根据。