铁屑去除酸法地浸采铀地下水中硝酸盐的试验研究

在酸法地浸采铀过程中,硝酸及硝酸盐的广泛使用使硝酸盐在地下不断累积并扩散到地下水中,这给矿区地下水造成了一定程度的污染.本试验以铁屑为还原剂,对该地下水中NO3--N的去除进行了批试验和动态试验研究.试验结果表明,铁屑可有效去除地下水中的NO3--N,其去除率随pH值的降低而逐渐升高;溶液中共存的Ca2 、Mg2 对NO3--N的去除影响不大,而SO42-、HCO3-的存在可明显降低NO3--N去除率;铁屑最佳投加量为120 g/L,铁炭最佳体积比为1∶1;二级柱可以明显提高柱子的稳定运行时间,在55 h内NO3--N去除率可保持在93%以上,去除效果较好.     

红壤和黄泥土对不同浓度六氯苯的吸附与解吸特征

采用批量平衡试验的方法,研究了不同初始浓度的六氯苯在红壤和黄泥土表面的吸附与解吸特征. 结果表明,六氯苯在红壤和黄泥土表面的吸附与解吸行为均可用Freundlich方程进行很好的拟合,其相关系数(R2)在0.97-0.99之间,并表现为非线性特征. 六氯苯在红壤和黄泥土上吸附的KadsF值均小于其解吸的KdesF值,说明六氯苯在这两种土壤表面的解吸表现为一定的滞后效应. 随着初始浓度的升高,其滞后效应增强,两者呈线性相关. 用不同方程对滞后系数H,ω和λ进行量化,发现不同浓度的六氯苯在土壤表面的解吸过程表现出正滞后效应.     

超滤处理洗涤污水循环利用的中试研究

采用不同材质国产超滤膜聚丙烯（PP）、聚丙烯腈（PAN）和聚砜（PS）,进行了洗涤污水处理循环利用的现场中试研究.结合超滤工艺出水水质和膜污染分析,3种膜材质中PAN膜较优,有效去除了水中浊度、悬浮物、油脂等污染物,一定程度保留了游离阴离子表面活性剂（LAS）,长期循环洗涤对衣物的白度无不良影响.根据相关性分析,超滤出水较高COD值很大程度上是由水中LAS引起的.超滤膜对细菌、大肠菌群的去除率较低,出水通过紫外消毒,当紫外线密度≥3?750 J/m²时,微生物水平能够达到国家饮用水水质标准.根据不同水力反冲洗条件下膜渗透通量和净产水量比较,PAN膜最佳水力反冲洗条件为0.5 h反冲洗2 min.长期运行时超滤膜化学清洗方法采用碱洗法方便有效.     

淮河流域安徽省2007年的暴雨洪水特性分析

为系统研究淮河流域安徽省2007年的暴雨洪水特征,对降雨过程和暴雨频率进行了分析.结果表明,2007年的主要暴雨特性是梅雨时间长,梅雨量淮河以北多、淮河以南少,降雨时间长、强度大、范围广,降雨时空分布不均.通过淮河干支流洪水过程和淮河干流洪水特征值的分析,结果表明,2007年的主要洪水特性是水位高、流量大,高水位持续时间长,干支流洪水并发,洪水组合恶劣.虽然淮河干流经过了大规模的治理,2007年洪水期间沿淮启用了蒙洼等9个行蓄洪区,但淮河中游仍然持续高水位,润河集至汪集段超过历史最高洪水位,表明淮河流域洪水灾害较为严重,需要进一步研究如何科学调度沿淮行蓄洪区、如何协调淮河与洪泽湖之间的关系,以便更好地进行该流域的洪水管理.     

广西喀斯特干旱农业区干旱遥感监测模型研究

广西中部喀斯特平原区是广西重要的粮食生产基地,但旱灾已成为该地区经济发展的障碍.利用EOS/MODIS数据,采用植被状态指数(IVC)和温度条件指数(ITC),构建了干旱指数ID的遥感监测模型, 统计分析了ID与农业受旱率的相关系数,从而确定了模型中各参数的权重系数.将该模型应用于2005年秋旱监测,经与旱情实况及前人研究成果进行对比分析,验证了干旱指数ID的有效性.通过对ID随ITC和IVC变化的敏感性评价,结果表明,ITC和IVC都能反映旱情变化,但ITC反映旱情的敏感性高于IVC,以ITC和IVC为因子构建的干旱遥感监测模型适用于广西中部喀斯特干旱农业区的旱情遥感监测.     

Organic matter and concentrated nitrogen removal by shortcut nitrification and denitrification from mature municipal landfill leachate

An UASB＋Anoxic/Oxic （A/O） system was introduced to treat a mature landfill leachate with low carbon-to-nitrogen ratio and high ammonia concentration. To make the best use of the biodegradable COD in the leaehate, the denitrifieation of NOx^--N in the reeireulation effluent from the elarifier was carried out in the UASB. The results showed that most biodegradable organic matters were removed by the denitrifieation in the UASB. The NH4^＋-N loading rate （ALR） of A/O reactor and operational temperature was 0.28- 0.60 kg NH4^＋-N/（m^3-d） and 17-29℃ during experimental period, respectively. The short-cut nitrification with nitrite accumulation efficiency of 90%-99% was stabilized during the whole experiment. The NH4^＋-N removal efficiency varied between 90% and 100%. When ALR was less than 0.45 kg NH4^＋-N/（m^3.d）, the NH4^＋-N removal efficiency was more than 98%. With the influent NH4^＋-N of 1200-1800 mg/L, the effluent NH4^＋-N was less than 15 mg/L. The shortcut nitrification and denitrifieation can save 40% carbon source, with a highly efficient denitrifieation taking place in the UASB. When the ratio of the feed COD to feed NH4^＋-N was only 2-3, the total inorganic nitrogen （TIN） removal efficiency attained 67%-80%. Besides, the sludge samples from A/O reactor were analyzed using FISH. The FISH analysis revealed that ammonia oxidation bacteria （AOB） accounted for 4% of the total eubaeterial population, whereas nitrite oxidation bacteria （NOB） accounted only for 0.2% of the total eubaeterial population.     

中国企业低碳环境与低碳管理再造

2012年底京都议定书第一承诺期到期后,各国将制定更具有操作性的碳减排目标,世界低碳发展的要求越来越强烈,低碳发展的路径逐步从宏观治理向宏观与微观结合过渡。目前我国低碳经济的发展主要处在政府推动为主、大企业探索性行动的阶段,今后企业将逐渐在低碳发展中发挥主力作用。企业面临的低碳环境主要包括宏观低碳发展环境、行业低碳竞争环境、微观低碳管理环境三个层面。企业管理需要根据低碳发展的要求重新更新再造。从企业内部来看,企业基本活动的低碳管理再造包括内部后勤、生产运营、外部后勤、市场和销售、售后服务等的低碳管理再造。而辅助方面的低碳管理再造主要包括采购低碳管理、技术开发低碳管理、人力资源低碳管理和企业基础设施低碳管理等。从企业外部资源管理角度来说,企业的低碳管理主要包括供应商的低碳协同管理和其他合作伙伴的低碳协同管理。本文根据我国企业的低碳环境和低碳再造的内容,提出了企业低碳管理再造的相关策略。     

Effects of cadmium on forearm bone density after reduction of exposure for 10 years in a Chinese population

The main focus of this study was to evaluate long term effects of cadmium on forearm bone mineral density after stopping ingestion of cadmium-polluted rice for 10 years in a Chinese population. A total of 532 persons (338 women and 194 men), living in control, moderately and heavily polluted areas, were included in this study. The residents living in the polluted area ceased ingesting cadmium-polluted rice in 1996. All participants were require to answer a questionnaire and the bone mineral density (BMD) was measured by dual energy X-ray absorptiometry (DXA) at the proximal radius and ulna. Samples of urine and blood were collected for determination of cadmium in urine (UCd) and blood (BCd).The BMD of subjects living in the heavily polluted area was significantly lower than that of those living in control area in both men and women (p < 0.01). For the people living in the moderately polluted area, only the women's BMD was greatly lower compared to that in the control area (p < 0.05). The BMD declined with the increasing BCd and UCd in both sexes, especially in the highest level (BCd > 5 µg/L, UCd > 10 µg/g crea) groups (p < 0.01). It was found that there were significant differences in the prevalence of osteoporosis among the different areas (χ² = 13.046, p = 0.0003) and different UCd groups (χ² = 4.511, p = 0.0337) in women, but not in men (χ² = 0.962, p = 0.3268; χ² = 1.906, p = 0.1675). But a significant difference exists in the prevalence of osteoporosis among different BCd groups in both genders (χ² = 9.304, p = 0.00229, in women; χ² = 4603, p = 0.0319, in men). This study suggested that cadmium could play a long-term role on bone and more attention should be paid to cadmium effects on bone metabolism after reduction of exposure.     

Perfluorosulfonates and perfluorocarboxylates in snow and rain in Dalian,China

Samples of precipitation events (snow and rain) in Dalian, a typical coastal town in China, were analyzed for perfluorosulfonates (PFSAs) and perfluorocarboxylates (PFCAs) to investigate atmospheric contamination by these compounds. In the snow event on December 16, 2006, samples were collected from 21 different sites and in another 6 precipitation events, samples were collected from a single location. Four PFSAs (C4, C6, C8, C10) and seven PFCAs (C6–12) were analyzed. Among the homologues, perfluorooctane sulfonate (PFOS) concentrations were the highest with a geometric mean (GM) of 145 ng/L (n = 21) during the snow event on December 16, 2006, followed by perfluorooctanoate (PFOA) with a GM of 24.7 ng/L (n = 21). Concentrations of perfluorobutane sulfonate (PFBS), perfluorohexane sulfonate (PFHxS) and perfluoroheptanoate (PFHpA) were more than two orders of magnitude lower than that of PFOS. Other PFSAs and PFCAs were found to be below the limit of detection in all the samples. In other 6 precipitation events, PFSAs and PFCAs were detected approximately in the same order of magnitude in both snow and rain. The results indicate that wet deposition may be a potential transport mechanism of perfluorinated chemicals in the environment.