不同载体材料对厌氧氨氧化效果影响的研究

文章分别采用水性聚氨酯(WPU)和活性炭2种材料作为生物载体,在2个不同的上流式厌氧污泥床(UASB)反应器中接种包埋污泥和生物活性炭,采用人工配水进行连续实验,观测厌氧氨氧化反应器启动过程中各种含氮化合物的变化,以考察不同载体材料对厌氧氨氧化过程的影响。文章在生物活性炭反应器中成功驯化了采自污水处理厂的普通厌氧污泥,证明了从环境中驯化培养厌氧氨氧化菌的可能性。通过2个阶段中脱氮效率的比较,发现以水性聚氨酯包埋材料作为未驯化细菌载体并无明显优势,反而成为传质的障碍;而采用生物活性炭则可以迅速达到提高局部生物量、聚集功能菌、屏蔽不利环境的干扰等作用,是理想的微生物载体。     

Fractionation of residual Al in natural water treatment from reservoir with poly-aluminum-silicate-chloride (PASiC): Effect of OH/Al, Si/Al molar ratios and initial pH

An aluminum fractionation study was conducted for a surface reservoir water treatment to understand the performance of poly-aluminum-silicate-chloride (PASiC) in terms of the residual Al fractions as a function of initial pH. The coagulation performance expressed as turbidity and organic matter removal was established as supporting data. Some extra data were evaluated in terms of the residual Al ratio of the composite PASiC coagulant. The main residual Al sources were the Al fractions derived from the use of PASiC. The turbidity and organic matter removal ability was optimal at initial pH 6.00-7.00, while the concentrations of various residual Al species and the residual Al ratio of PASiC were minimal at an initial pH range of 7.00-8.00. Under the conditions of OH/Al molar ratio = 2.00 and Si/Al molar ratio = 0.05, PASiC had superior coagulation performance and comparatively low residual Al concentrations. The Al fraction in the composite PASiC coagulant seldom remained under such conditions. Experimental data also indicated that the suspended (filterable) Al fraction was the dominant species, and organic-bound or organo-Al complex Al was considered to be the major species of dissolved Al in water treated by PASiC coagulation. Additionally, the dissolved inorganic monomeric Al species dominated the dissolved monomeric Al fraction.     

Measurement of air exchange rates in different indoor environments using continuous CO2 sensors

A new air exchange rate (AER) monitoring method using continuous CO₂ sensors was developed and validated through both laboratory experiments and field studies. Controlled laboratory simulation tests were conducted in a 1-m³ environmental chamber at different AERs (0.1-10.0 hr^-1). AERs were determined using the decay method based on box model assumptions. Field tests were conducted in classrooms, dormitories, meeting rooms and apartments during 2-5 weekdays using CO₂ sensors coupled with data loggers. Indoor temperature, relative humidity (RH), and CO₂ concentrations were continuously monitored while outdoor parameters combined with on-site climate conditions were recorded. Statistical results indicated that good laboratory performance was achieved: duplicate precision was within 10%, and the measured AERs were 90%-120% of the real AERs. Average AERs were 1.22, 1.37, 1.10, 1.91 and 0.73 hr^-1 in dormitories, air-conditioned classrooms, classrooms with an air circulation cooling system, reading rooms, and meeting rooms, respectively. In an elderly particulate matter exposure study, all the homes had AER values ranging from 0.29 to 3.46 hr??1 in fall, and 0.12 to 1.39 hr^-1 in winter with a median AER of 1.15.     

Identification of rice cultivars with low brown rice mixed cadmium and lead contents and their interactions with the micronutrients iron, zinc, nickel and manganese

Paddy fields in mining areas are usually co-contaminated by a cocktail of mixed toxic heavy metals (e.g., Cd and Pb in Pb/Zn mines). However, previous studies on rice cultivars screened for effective metal exclusion have mostly focused on individual metals, and have been conducted under pot-trial or hydroponic solution conditions. This study identified rice cultivars with both low Cd and Pb accumulation under Cd-and Pb-contaminated field conditions, and the interactions of the toxic elements Cd and Pb with the micronutrient elements Fe, Zn, Mn and Ni were also studied. Among 32 rice cultivars tested, there were significant differences in Cd (0.06-0.59 mg/kg) and Pb (0.25-3.15 mg/kg) levels in their brown rice, and similar results were also found for the micronutrient elements. Significant decreases in concentrations of Fe and Mn were detected with increasing Cd concentrations and a significant elevation in Fe, Mn and Ni with increasing Pb concentrations. A similar result was also shown by Cd and Ni. Three cultivars were identified with a combination of low brown rice Cd and Pb, high micronutrient and grain yield (Wufengyou 2168, Tianyou 196 and Guinongzhan). Present results suggest that it is possible to breed rice cultivars with low mixed toxic element (Cd, Pb) and high micronutrient contents along with high grain yields, thus ensuring food safety and quality.     

Rapid decolorization of Acid Orange II aqueous solution by amorphous zero-valent iron

Some problems including low treatment capacity, agglomeration and clogging phenomena, and short working life, limit the application of pre-treatment methods involving zero-valent iron (ZVI). In this article, ZVI was frozen in an amorphous state through a melt-spinning technique, and the decolorization effect of amorphous ZVI on Acid Orange II solution was investigated under varied conditions of experimental variables such as reaction temperature, ribbon dosage, and initial pH. Batch experiments suggested that the decolorization rate was enhanced with the increase of reaction temperature and ribbon dosage, but decreased with increasing initial solution pH. Kinetic analyses indicated that the decolorization process followed a first order exponential kinetic model, and the surface-normalized decolorization rate could reach 2.09 L/(m². min) at room temperature, which was about ten times larger than any previously reported under similar conditions. Recycling experiments also proved that the ribbons could be reused at least four times without obvious decay of decolorization rate and efficiency. This study suggests a tremendous application potential for amorphous ZVI in remediation of groundwater or wastewater contaminated with azo dyes.     

活性污泥中超氧化物歧化酶(SOD)活性测定影响因素

研究以污水生物处理中的活性污泥为对象,采用氮蓝四唑光还原法测定超氧化物歧化酶(SOD)活性,从样品制备和保存方面探讨了是否添加溶菌酶液、细胞破碎时间、酶液保存时间与保存温度等因素对SOD活性测定的影响。研究表明,溶菌酶液的加入提高了细胞破碎效果;细胞破碎的条件为99次(工作3 s,停3 s),时间为40 min时破碎效果最好;酶液保存时间在4 h内最佳;-20℃保存比4℃保存对酶活性影响小。最佳检测条件为:取样量为1 mL时,反应温度为30℃,反应时间为20 min时,SOD酶活性最大。     

LIDAR技术在内陆水系监测管理中应用综述

机载激光雷达(Light Detection and Ranging,LIDAR)测距系统是20世纪90年代发展起来的高新技术,该系统是集激光、全球定位系统和惯性导航系统3种技术于一体的测量系统,能够快速、精确的获取物体三维数据。文章简要说明了LIDAR技术的基本原理。介绍了国外LIDAR技术在内陆河流监测中的应用,如河网测绘、河漫滩的监测管理、河岸侵蚀监测、洪水监测管理等内陆水系监测管理实例。通过对流域范围的LIDAR点云数据进行滤波与分类,建立数字高程模型,或结合使用地理信息系统、遥感影像、全球定位系统采集的数据,来实现上述实例。简要评述了LIDAR技术在内陆水域监测管理方面的优势,以及当前我国内陆水系监测管理的技术现状。通过国外典型案例说明LIDAR技术在我国内陆水系监测管理中广阔的应用前景。     

重金属对硫酸盐还原菌影响

含重金属硫酸盐废水是我国工业水污染的突出问题,利用硫酸盐还原菌的生物去除重金属的方法具有投资少、成本低、能耗少、去除率高,没有二次污染等优点而成为研究的热点。文章以混合培混养物作为接种污泥,考察不同浓度的重金属离子(Cu2+、Cd2+、Ni2+、Hg2+)对硫酸盐还原菌(Sulfate reducing bacteria,SRB)的抑制作用。研究表明:10 mg/L的Cu2+、Cd2+和20 mg/L的Hg2+对SRB还原硫酸盐的影响较小,硫酸盐最大去除率可分别达到94.1%、94.6%、91.3%,与空白(93.9%)相近;20 mg/L的Cu2+对SRB的抑制最为强烈,硫酸盐最大还原率仅为48.2%,剩余金属离子(Cd2+、Ni2+、Hg2+)都分别随着浓度的增大而对SRB的抑制作用增强;相同浓度的重金属离子对SRB的抑制顺序为Ni2+>Cu2+>Cd2+>Hg2+,抑制浓度分别为10、20、30、60 mg/L。最后阐述了各个反应器中硫酸盐还原率最大时,(WCOD/WSO42-)与硫酸盐还原率的关系。     

华南沿海某大气背景点黑碳气溶胶污染特征

黑碳气溶胶(BC)因其显著的气候效应和对人类健康的危害而成为研究的热点。研究背景点位BC的浓度水平和来源特征有助于掌握BC在区域尺度上的辐射强迫特性和环境影响。2009年秋季在华南沿海某区域大气背景点进行了为期约40 d的BC在线观测。观测期间BC的平均浓度为(2.34±1.33)μg/m3,与其它区域背景点相比处于较高水平。利用中尺度天气研究和预报系统WRF模拟的高分辨率三维气象场数据驱动HYSPLIT-4反向轨迹模式,模拟观测期间每小时的气团轨迹,将所有轨迹分为来源特征明显的东北沿海、北方内陆、香港方向和东南海面方向四类。当受到东北沿海来源气团影响时,BC的浓度为平均水平的1.4倍,BC和CO有较好的线性相关关系,而其它三类气团影响时的BC浓度都低于平均浓度,且BC和CO的相关关系很差,说明来自东北沿海地区的较近距离区域传输是影响该背景点大气BC的主要源区。     

一种新型生物絮凝剂FM-2絮凝特性及稳定性考察

文章对絮凝剂FM-1的储存稳定性以及絮凝活性分布进行了考察,发现其絮凝活性物质主要分布于上清液之中,加之储存稳定性较差的特点,为絮凝剂FM-2的制备提供了前提。絮凝剂FM-2的最佳絮凝率高达99.21%,其储存时间较长,30 d内其絮凝率可保持在90%以上;而且还具有较好的热稳定性,当加热温度从70℃升高到100℃,其絮凝率均保持在95%以上。