改良A2/O工艺的运行及除磷实践

介绍了采用一种两点进水,一点进泥的改良A2/O工艺处理城市污水的方法,由多次实验室观测的数据来看,预缺氧段对硝酸盐氮的去除是有很大帮助的。同时还对该厂的除磷加药问题进行了深入的探讨。发现采用聚合铝铁对TP的去除率远远高于三氯化铁。旱季进水的碳源基本可以满足生物除磷的需要,只要投加少量除磷药剂就能达到出水水质要求,而雨季时则要加大除磷药剂的投加量。     

改性炭对PH3的吸附性能研究

为利用黄磷尾气中的高浓度CO气体,通过钢瓶配气模拟和气相色谱GC-14C测定的方法,选出了净化PH3气体的最佳改性炭;用正交实验法优化了吸附净化实验条件;通过X射线光电子能谱对改性活性炭进行表征。结果表明:铜阳离子改性炭的净化效果最好;最佳实验条件是反应温度95℃、氧含量3%、气体流量0.2L/min、浸渍液浓度0.3mol/L、活性碳粒径4mm和焙烧温度350℃。     

改性壳聚糖对酚类污染物的竞争吸附研究

采用庚醛与壳聚糖反应生成schiff’s碱,NaBH4还原制备N-烷基化壳聚糖衍生物,并用反相HPLC-紫外检测研究了改性壳聚糖对酚类化合物的竞争吸附。试验了吸附时间、溶液pH值、酚的浓度等因素对水中共存酚类污染物竞争吸附的影响。结果表明,庚醛改性壳聚糖优先去除水中2,4-二氯酚。     

胺硫改性生物炭对水溶液中不同重金属离子的吸附特性及吸附稳定性

以玉米秸秆为原料热裂解制备生物炭,利用二乙烯三胺和二硫化碳,通过酸化氧化,曼妮希反应胺基改性、二硫化碳巯基取代对生物炭进行胺硫双基团改性,研究胺硫改性生物炭(BC-SN)对Pb2+、Ni2+及Cd2+在单一和三元体系下的吸附特性和吸附稳定性.表征分析证实了生物炭表面胺硫双基团改性成功,且具有比表面积大、表面官能团丰富的...     

Degradation of benzophenone in aqueous solution by Mn-Fe-K modified ceramic honeycomb-catalyzed ozonation

Comparative studies of ozonation alone, ceramic honeycomb-catalyzed and Mn-Fe-K modified ceramic honeycomb catalyzed ozonation processes have been undertaken with benzophenone as the model organic pollutant. The experimental results showed that the presence of Mn-Fe-K modified ceramic honeycombs significantly increased the removal rate of benzophenone and TOC compared with that achieved by ozonation alone or ceramic honeycomb-catalyzed ozonation. The electron paramagnetic resonance （EPR） experiments verified that higher benzophenone removal rate was attribute to more hydroxyl radicals generated in the Mn-Fe-K modified ceramic honeycomb-catalyzed ozonation. Under the conditions of this experiment, the degradation rate of all the three ozonation processes are increasing with the amount of catalyst, temperature and value of pH increased in the solution. We also investigated the effects of different process of ozone addition, the optimum conditions for preparing catalyst and influence of the Mn-Fe-K modified ceramic honeycomb after multiple-repeated use.     

Hazard mitigation or mitigation hazard?

BACKGROUND, AIM AND SCOPE: Transgenic oilseed rape (Brassica napus L.; OSR) is estimated to be environmentally and economically problematic because volunteers and ferals occur frequently and because of its hybridisation potential with several wild and weedy species. A proposed mitigation strategy aims to reduce survival, in particular in conventional OSR crops, by coupling the transgenic target modification with a dwarfing gene to reduce competitive fitness. Our study allowed us to access potential ecological implications of this strategy. MATERIALS AND METHODS: On a large scale (>500 km(2)), we recorded phenological and population parameters of oilseed rape plants for several years in rural and urban areas of Northern Germany (Bremen and surroundings). The characterising parameter were analysed for differences between wild and cultivated plants. RESULTS: In rural areas, occurrences of feral and volunteer OSR together had an average density of 1.19 populations per square kilometre, in contrast to urban areas where we found 1.68 feral populations per square kilometre on average. Throughout the survey, the vegetation cover at the locations with feral OSR ranged from less than 10% to 100%. Our investigations gave clear empirical evidence that feral OSR was, on average, at least 41% smaller than cultivated OSR, independent of phenological state after onset of flowering. DISCUSSION: The findings can be interpreted as phenotypic adaptation of feral OSR plants. Therefore, it must be asked whether dwarfing could be interpreted as an improvement of pre-adaptation to feral environments. In most of the sites where feral plants occurred, germination and establishment were in locations with disturbed vegetation cover, allowing initial growth without competition. Unless feral establishment of genetically modified dwarfed traits are specifically studied, it would not be safe to assume that the mitigation strategy of dwarfing also reduces dispersal in feral environments. CONCLUSIONS AND RECOMMENDATIONS: With respect to OSR, we argue that the proposed mitigation approach could increase escape and persistence of transgene varieties rather than reducing them. We conclude that the development of effective hazard mitigation measures in the risk evaluation of genetically modified organisms requires thorough theoretical and empirical ecological analyses rather than assumptions about abstract fitness categories that apply only in parts of the environment where the plant can occur.     

桦木硫酸盐木素的改性及树脂的合成研究

本文对桦木硫酸盐木素的改性及其在酚醛树脂中的应用进行了研究。结果发现,利用单因素法对木素硫改性进行分析时,其最佳条件为：硫用量５％,碱用量４％,最高温度２６０℃,保温时间１５ｍｉｎ。改性后木素甲氧基含量由原来的１８．８１％变为１１．８４％。利用改性及未改性木素取代苯酚合成木素酚醛树脂时,当两种木素分别取代６０％的苯酚,使用桦木为单板时,基胶合强度虽然低于同样条件下酚醛树脂在胶合强度,但仍能达到国标     

双碱法旋流板塔烟气脱硫工艺

以旋流板塔为脱硫塔,对Ｎａ２ＣＯ３－Ｃａ（ＯＨ）２双碱法烟气脱碱工艺进行了实验研究,对影响充率的主要因素进行考察,如再生液ＰＨ值,溶液中Ｎａ＾２＋浓度、ＳＯ＾２－４浓度,液气比及气体中ＳＯ２初始浓度等。结果表明,选择以下工艺条件较为适宜：ＰＨ０＝７－８,Ｌ／Ｇ＝２－３Ｌ／同海高度     

Hydrogen sulphide removal from landfill gas

Control of odours should be considered to be a fundamental issue in order to site, design and manage sanitary landfills. With regard to construction and demolition (C&;D) debris, landfilling was the mainly adopted solution in many European Countries; in particular, gypsum drywalls can produce high concentrations of hydrogen sulphide (H₂S) in landfill gas ranging from 7 ppm to 100 ppm. In some cases also dangerous concentrations until to 12,000 ppm were detected. In this paper H₂S removal efficiency in a lab-scale vertical packed scrubber was investigated. Hydrogen sulphide abatement was evaluated for inlet H₂S concentrations of 1000–100–10 ppm, adjusting scrubbing liquid pH in the range 9–12.5 by means of caustic soda (NaOH 2N solution). Moreover, best operating conditions for the system were defined as well as H₂S abatement along the tower and liquid recirculation effectiveness in case of inlet H₂S concentration of 10 ppm (typical odour concentration). Results showed that pH of 11.5 in scrubbing liquid could be considered the best value for removal of different inlet H₂S concentrations, also taking into account parasitical consumption of NaOH due to CO₂ absorption. Moreover, in case of continuous working of the system at H₂S concentration of 10 ppm, strong removal efficiency was already obtained with a packed bed height of about 70 cm. Significant performances were ensured after 1 h of constant activity, consuming about 3 ml of soda per cubic meter of polluted air. Subsequently liquid blowdown was necessary.     

交替活性污泥工艺发展类型及研究方向

交替活性污泥工艺是在一个反应器或一组反应器中通过时间或空间的交替实现对污水的处理。从最初的SBR到各种改良形式,交替活性污泥工艺在控制系统、运行方式等方面迅速发展。传统的交替工艺只能适用于中小型污水处理,CAST、MSBR、UNITANK、多箱一体化工艺等通过运行方式组合,既提高了对处理规模的适应性,又能满足除磷脱氮要求。交替活性污泥工艺今后研究的重点是工艺组合优化,提高灵活性,特别是如何在单泥交替系统中解决除磷脱氮的矛盾,同时也要注意相应配套设备的开发,降低造价,提高可靠性。