炼化浓盐水处理与资源化工艺探讨＊

炼化污水深度处理回用是各炼化企业节水减排的主要措施之一。炼化企业反渗透(简称RO)污水脱盐回用装置在运行中暴露出末端高含盐污水的处置难题,影响了污水回用生产的连续运行。文章阐述近年来炼化企业高含盐污水处置现状、存在问题、国内外处理技术及发展趋势,在此基础上针对炼化企业特点,提出以热法、膜法为核心技术的浓盐水处理工艺耦合方案,为炼化企业解决污水回用瓶颈技术难题、实施污水"零排放"与发展循环经济提供借鉴与参考。     

藏西北高寒牧区草地退化现状与机理分析

以藏西北高寒牧区为研究区域,综合利用NOAA、MODIS卫星NDVI(归一化植被指数)、气象资料、社会统计资料并结合GIS技术,对藏西北高寒牧区的草地状况和退化机理作了分析。结果表明:①藏西北高寒牧区草地覆盖度等级呈正态分布,且中等偏下略多,地表植被总体上比较稀疏;②2005年区域内的草地退化总面积为14.19×10⁴km²,占区域天然草地总面积的39.64%,其中轻度退化面积最多,占退化总面积的65.96%,其次是中度和重度退化,分别占25.20%和8.84%;③草地退化的主要原因一是与近年来该区域的气候变化有关,二是草地超载率达到59.18%,过度放牧引起的草地退化和沙化现象也越来越严重,是局部草地退化的根本原因,人口的增加和人类活动频繁对草场的破坏,也是近年来草地退化的主要原因。     

一体化膜生物反应器处理低C/N污水试验研究

研究一体化连续流间歇曝气膜生物反应器(IMBR)处理低C/N城市污水的工艺效能。试验结果表明:反应器在曝气2 h、搅拌2 h的运行模式下,对COD、NH4+-N、TN和SS的平均去除率分别达到了87%,83.4%,75.4%和97.81%,各出水质量浓度平均值分别为17.5,4.59,7.63和2 mg/L,出水水质达到了GB/T18920-2002《城市污水再生利用城市杂用水水质》标准。     

高氮渗滤液缺氧/厌氧UASB-SBR工艺低温深度脱氮

在低温条件下,采用缺氧/厌氧UASB-SBR组合工艺处理实际垃圾填埋场渗滤液.结果表明,该工艺可实现有机物和氮的同步、深度去除.在进水COD平均为11950.2mg/L,NH4+-N为982.7mg/L的条件下,出水分别为390.1mg/L和2.9mg/L,去除率分别为96.7%和99.7%.同时,缺氧UASB1反应器的最大COD负荷达到13kg/(m3×d),最大COD去除速率为12.39 kg/(m3×d),具有高效缺氧反硝化和高效厌氧降解有机物反应的双重功效, 在SBR反应器的缺氧段和缺氧UASB,反应器内获得了99%以上的反硝化率.对于冬季水温分别为14.9,14.1,13.5,11.05℃的低温条件下,SBR反应器实现了完全硝化和反硝化,出水TN分别为4.1,5.7,14.1,16.5mg/L,达到了深度脱氮的目的.此外,在上述温度范围内,温度对反硝化速率(rN)的影响大于对硝化速率 (rDN)的影响, rN/rDN比值相对恒定.     

金属有机骨架材料低温脱硝技术研究进展

金属有机骨架材料（MOFs）因其独特的结构作为催化剂应用于SCR系统表现出较好的低温脱硝效果和较强的抗SO₂、抗H₂O性能。综述了几种较典型的MOFs催化剂及其改性产物的低温催化性能,以及MOFs材料应用于SCR技术的研究进展,指出：对含有两种或两种以上金属的复合MOFs材料的深入研究,是开发稳定性更高、抗SO₂抗H₂O能力更强的MOFs催化剂的重要思路;此外,对有机组成部分进行改性,提高有机配体的热稳定性也是一个重要的研究思路。     

低压脉冲袋式收尘技术在银转炉有价烟尘回收系统中的应用

通过对精心设计后的某有色行业金银溶炼收尘系统的介绍,对比分析了新老两代脉冲袋式收尘技术的性能参数。阐明了在回收该系统有价金属粉尘中,以低压快速脉冲袋式收尘器替代传统高压脉冲袋式收尘器后的成功应用,以及取得的较好社会效益、经济效益和环境效益。     

长袋低压脉冲袋式除尘器在水泥立窑烟气除尘上的应用

比较了几种用于水泥立窑烟气除尘装置后 ,长袋低压脉冲袋式除尘器的优势凸现 ,对其在广州新华水泥厂实际使用出现的问题作了详细分析 ,并提出了解决办法     

LONG‐TERM CHANGES IN REGIONAL HYDROLOGIC REGIME FOLLOWING IMPOUNDMENT IN A HUMID‐CLIMATE WATERSHED1

ABSTRACT: We analyzed the type of hydrologic adjustments resulting from flow regulation across a range of dam types, distributed throughout the Connecticut River watershed, using two approaches: (1) the Index of Hydrologic Alteration (IHA) and (2) log‐Pearson Type III flood frequency analysis. We applied these analyses to seven rivers that have extensive pre‐and post‐disturbance flow records and to six rivers that have only long post‐regulation flow records. Lastly, we analyzed six unregulated streams to establish the regional natural flow regime and to test whether it has changed significantly over time in the context of an increase in forest cover from less than 20 percent historically to greater than 80 percent at present. We found significant hydrologic adjustments associated with both impoundments and land use change. On average, maximum peak flows decrease by 32 percent in impounded rivers, but the effect decreases with increasing flow duration. One‐day minimum low flows increase following regulation, except for the hydro‐electric facility on the mainstem. Hydrograph reversals occur more commonly now on the mainstem, but the tributary flood control structures experience diminished reversals. Major shifts in flood frequency occur with the largest effect occurring downstream of tributary flood control impoundments and less so downstream of the mainstem's hydroelectric facility. These overall results indicate that the hydrologic impacts of dams in humid environments can be as significant as those for large, multiple‐purpose reservoirs in more arid environments.     

A SIMPLE METHOD FOR ESTIMATING BASEFLOW AT UNGAGED LOCATIONS1

ABSTRACT: Baseflow, or water that enters a stream from slowly varying sources such as ground water, can be critical to humans and ecosystems. We evaluate a simple method for estimating base‐flow parameters at ungaged sites. The method uses one or more baseflow discharge measurements at the ungaged site and longterm streamflow data from a nearby gaged site. A given baseflow parameter, such as the median, is estimated as the product of the corresponding gage site parameter and the geometric mean of the ratios of the measured baseflow discharges and the concurrent discharges at the gage site. If baseflows at gaged and ungaged sites have a bivariate lognormal distribution with high correlation and nearly equal log variances, the estimated baseflow parameters are very accurate. We tested the proposed method using long‐term streamflow data from two watershed pairs in the Driftless Area of southwestern Wisconsin. For one watershed pair, the theoretical assumptions are well met; for the other the log‐variances are substantially different. In the first case, the method performs well for estimating both annual and long‐term baseflow parameters. In the second, the method performs remarkably well for estimating annual mean and annual median baseflow discharge, but less well for estimating the annual lower decile and the long‐term mean, median, and lower decile. In general, the use of four measurements in a year is not substantially better than the use of two.     

EVALUATION OF THE ROSGEN STREAM CLASSIFICATION SYSTEM IN CHEQUAMEGON‐NICOLET NATIONAL FOREST,WISCONSIN1

ABSTRACT: Data collected from 121 stream reaches during 1991 to 1993 were evaluated to determine the applicability of the Rosgen Stream Classification System (RSCS) to the low relief terrain within the Chequamegon‐Nicolet National Forest (CNNF) in Wisconsin, USA. All reaches were classified to RSCS Level I and II except that 10.7 percent had sinuosities below the continuum limits and one reach had a predominantly organic substrate. Five of eight possible RSCS Level I types were observed including B, C, D, A, E, and F; 86 percent were C and E types. Seventeen of 94 possible RSCS Level II types were observed. Most reaches were slightly entrenched, had low to moderate width/depth ratios, relatively low sinuosity, low slope, and sand or gravel as the dominant channel material. Discriminant analyses were used to verify the applicability of RSCS for streams within the CNNF; discriminant functions correctly classified 92.5 and 94.7 percent of the Level I and II RSCS types, respectively. When limits for E and F types were modified slightly at Level II by adding an additional category for slopes less than 0.1 percent (a modification we recommend for low relief terrain), discriminant functions correctly classified 99.1 percent of the types. Adding another slope break at 0.3 percent produced similar results. Based on our analyses, RSCS works well within the CNNF and is probably applicable to other areas with low‐relief terrain.