风干工艺强化催化氧化除氨氮/锰活性滤料膜负载

为强化地下水处理中催化氧化除氨氮/锰活性滤料表面膜负载强度,系统研究了风干温度对锰氧化物滤料氧化膜的活性、负载强度及负载量的影响,将不同温度风干的生产性滤料填充滤柱,检测沿滤柱深度的氨氮、锰浓度随时间的变化,分析风干温度对生产滤料活性恢复期、除氨氮锰能力和膜负载强度的影响规律.结果表明,滤料经风干处理可以明显缩短滤柱除氨氮/锰的恢复期,其中除氨氮活性最先恢复的是自然风干和60℃风干滤柱;经过风干处理的滤料氨氮/锰的处理能力明显增强,出水氨氮浓度更稳定,不同风干温度之间的差异不明显;滤料风干能显著增强膜负载强度;滤料在运行过程中,表面膜负载量呈现先减少后增长的趋势,特别是未风干处理滤料的运行初期膜量下降明显.利用XRD测定滤料样品表面锰氧化物的晶体结构,比较不同温度风干的初始滤料发现它们具有相同复杂的晶型.     

Harvesting of rainwater and brooklets water to increase mountain agricultural productivity: A case study from a dry valley of southwestern China

In semi-arid valleys of southwestern China, seasonal shortage of water is the major contributing factor to low and unstable crop yield. Harvesting of both rainwater and brooklets water in the semi-arid valleys of Ningnan county of Sichuan Province has brought about considerable economic and environmental change. Brooklet water is collected throughout the year but mainly during the rainy season in a series of ponds while rainwater is harvested in underground tanks constructed on road side or land boundaries with only a small opening above ground to save limited cropland. Increased water availability has promoted cultivation of sugarcane, tobacco, and mulberry, and increased per unit area yield of food crops. Sericulture, sugarcane and tobacco have become three important sources of farmers' income. The water harvesting has contributed considerably to increased rural income, poverty reduction, reduced soil erosion and improvement in overall environment. Government has played a key role in planning and implementation of water harvesting programmes. Financial support of government and clear ownership of water harvesting facilities are critical for the success of the programme. Application of similar water harvesting techniques in other areas with similar biophysical conditions would contribute to enhancing the rural economy and alleviating poverty.     

攀西地区主要蔬菜基地土壤重金属含量及评价

对攀西地区米易县蔬菜基地的土壤进行采样,用原子吸收和石墨炉光谱法分析土壤中Cr、Cu、Ni、Zn、Pb、Cd、As和Hg8种元素的含量。蔬菜基地土壤重金属平均含量分别为Cr 68．8mg／kg、Cu 22．3mg／kg、Ni27．6mg／kg、Zn 146．2mg／kg、Pb31．7mg／kg、Cd0．258mg／kg、As10．3mg／kg、Hg0．0618mg／kg。根据土壤环境质量标准（GB15618—1995）对检测结果进行了单因子和多因子综合污染指数评价。分析表明调查区内少部分蔬菜基地土壤受到轻度重金属污染,主要污染物为Cd元素,其余重金属元素的含量均在安全警戒线内。     

活性炭纤维（ACF）脱硫动力学研究

本文在消除内外扩散的条件下对SO2－O2－N2－H2O（g）体系下,自制ACF脱除气相中二氧公硫的过程进行了动力学研究。认为在F＞400ml/min时可消除外扩散的影响。在空速为5000Nm3／tACF*h～24000Nm3／tACF*h,SO2浓度为0.1%～0.5%,氧浓度为1%～14%,反应温度为323K～403K,增湿温度在313K～363K之间探讨了温度、水、SO2及O2对ACF脱硫性能的影响,求出了反应动力学方程为rD＝0.006exp(-8852.8/RT)Cso20.4936Co20.7381CH2O0.7021。     

三岔湖沉积物揭示的湖泊营养化进程与人类活动的关系

在210Pb和137Cs定年基础上,研究了三岔湖沉积物理化性质的垂直和水平变化格局,揭示了三岔湖沉积物的特性、沉积速率、碳氮磷变化格局与人类活动和湖泊富营养化进程的关系.三岔湖不同时期沉积物的TOC、TN、TP与三岔湖水质呈现同样的变化格局.建库初期三岔湖水质为贫营养状态,随着人类活动的加剧,水质不断恶化.沉积物的沉积速率和碳氮磷含量的变化与人类活动密切相关,工、农、渔业、旅游业等人类活动导致三岔湖湖泊营养化进程加快.控制人类活动的强度是改善湖泊水质的关键.网箱养殖是三岔湖沉积物中磷的最重要来源,停养后沉积物中磷含量的下降将是一个相当漫长的过程.     

A2/O工艺脱氮除磷的中试试验研究

以某污水处理厂初沉池出水为中试试验A2/O工艺进水,连续运行,考察温度、泥龄、溶解氧、厌氧停留时间对氮磷的去除情况.结果表明,系统硝化功能以20℃为界,低于此温度时系统氨氧化速率(AUR)由10.4mgNH4+;-N/L·h降为8.1 mgNH4+-N/L·h,亚硝酸盐氧化速率(NUR)由6.1 mgNO2--N/L·h降为4.8 mgNO2--N/L·h,氨氮去除率由98.8％降为51.2％.在低温条件下,泥龄由13 d延长至16 d,氨氮去除率升至82.5％.曝气采用固定氧供给模式和非固定氧供给模式对TN去除率影响较大,去除率分别为78.1％和63.8％.厌氧水力停留时间由0.93 h提高至1.86 h,TP去除率由40.5％提高至67.3％,厌氧阶段磷浓缩比由1.36倍提高至4.29倍.     

基层监测站废气应急监测应注意的问题

县（市）级环境监测站开展废气应急监测工作,首先要建立本辖区内完整、详细的废气污染源及潜在风险源的台帐,同时要建立有针对性和操作性的应急监测预案。在应急监测装备的配备上要结合本辖区内的污染情况和自身财力状况均衡考量。在废气应急监测中还要弄清应急监测的目的,注意监测人员的自身防护,不能忽视跟踪监测和应急现场监测后的总结提高等工作。     

A comparison study of the start-up of a MnOx filter for catalytic oxidative removal of ammonium from groundwater and surface water

As an efficient method for ammonium (NH4+) removal, contact catalytic oxidation technology has drawn much attention recently, due to its good low temperature resistance and short start-up period. Two identical filters were employed to compare the process for ammonium removal during the start-up period for ammonium removal in groundwater (Filter-N) and surface water (Filter-S) treatment. Two types of source water (groundwater and surface water) were used as the feed waters for the filtration trials. Although the same initiating method was used, Filter-N exhibited much better ammonium removal performance than Filter-S. The differences in catalytic activity among these two filters were probed using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and compositional analysis. XRD results indicated that different manganese oxide species were formed in Filter-N and Filter-S. Furthermore, the Mn3p XPS spectra taken on the surface of the filter films revealed that the average manganese valence of the inactive manganese oxide film collected from Filter-S (FS-MnOx) was higher than in the film collected from Filter-N (FN-MnOx). Mn(IV) was identified as the predominant oxidation state in FS-MnOx and Mn(III) was identified as the predominant oxidation state in FN-MnOx. The results of compositional analyses suggested that polyaluminum ferric chloride (PAFC) used during the surface water treatment was an important factor in the mineralogy and reactivity of MnOx. This study provides the theoretical basis for promoting the wide application of the technology and has great practical significance.     

Recovery of Cu(Ⅱ) from aqueous solution by induced crystallization in a long-term operation

The feasibility of copper recovery by induced crystallization in a long period(174 days) was investigated in a seeded fluidized bed reactor(FBR). The process was divided into 3 periods according to different influent conditions, and the period III was separated into III-a and IIIb due to the adjustment of the molar ratio of CO_3~(2-)concentration to copper concentration([CT]/[Cu~(2+)]). The removal efficiency could exceed 95% and the average effluent copper concentration decreased to 3.0 mg/L. The mean particle size of seed grains with copper crystals coating on, raised to 0.36 mm from initial 0.18 mm. During period III-a, the supersaturation exceeded 2.88 × 104, the removal efficiency decreased to 60%–80% and the particle size dropped to 0.30 mm, due to the generation of fines by homogeneous crystallization and seeds breaking. And the morphology of the crystals on the seed grains changed from rod-like to spherical which lead to the particle size decreasing. In period III-b,the supersaturation was modified by adjusting the molar ratio of [CT]/[Cu2+] to 1.2 from 2.The efficiency was back to 95% and the mean particle size grew to 0.36 mm at the end of IIIb, the crystals coating on the seeds turned back to rod-like products of good stability. This study illustrated that the copper salt crystal could keep on growing on the seed grains for over 150 days, the feasibility and controllability of copper recovery by induced crystallization process in FBR were satisfactory, even under the dramatic changes in influent conditions.     

一株芽胞杆菌和一株黄杆菌代谢芘的摄取方式解析

通过溶剂萃取、薄层色谱和紫外分光光度法研究了一株芽胞杆菌CN2和一株黄杆菌CN4在初始pH=6.00的条件下对芘的降解过程.研究表明:芘降解液的pH值随降解时间向中性波动变化;用牛肉膏蛋白胨培养出的CN2菌体表面具有亲水性,CN4菌体表面具有疏水性,CN2表面疏水性在芘的降解过程中随时间有变大的趋势,CN4表面疏水性在芘的降解过程中随时间有变小的趋势;从芘降解的整个过程看,大部分时间CN2的降解比CN4的快,CN4菌体捕获的芘量比CN2要大,尤其在接种刚开始的一段时期较为明显;细胞表面、细胞壁中、细胞内部均有芘富集迹象,其中细胞表面富集的芘最多.根据试验结果推测,在菌株对芘的降解过程中吸附和降解同时发生;菌体对芘首先通过表面吸附或其它方式结合,随后溶人细胞壁中,跨过细胞膜进入细胞内被降解;这个传质过程很可能不是连续的,而是由细菌控制的主动的间歇的动态过程.