The importance of temperature in assessing iron pipe corrosion in water distribution systems

Temperature is expected to play a significant role in the corrosion of iron pipes in drinking water distribution systems. Temperature impacts many parameters that are critical to pipe corrosion including biological activity, physical properties of the solution, thermodynamic and physical properties of corrosion scale, and chemical rates. Moreover, variations in temperature and temperature gradients may give rise to new corrosion phenomena worthy of consideration by water treatment personnel.     

Se(Ⅳ)和Se(Ⅵ)对小白菜生长及生理效应的影响

用盆栽试验研究了不同含量Se(Ⅳ)和Se(Ⅵ)对小白菜生长和生理效应的影响.结果表明,不同含量Se(Ⅳ)和Se(Ⅵ)对小白菜体生长和生理代谢的影响不尽相同.低含量硒（Se(Ⅳ)<10.0 mg·kg-1、Se(Ⅵ)<5.0 mg·kg-1）能够促进小白菜的生长,使其根变粗, 诱导脯氨酸的产生,阻止丙二醛（MDA）的合成,增强白菜的抗逆性,使其生物量明显提高;高含量硒会抑制小白菜的生长,导致植物体内脯氨酸合成下降,MDA含量增加,叶及根系生长受到抑制,地上和地下部干重显著急速下降（p<0.01）.小白菜根长、叶面积等生长指标均随Se(Ⅳ)和Se(Ⅵ)含量的增大而显著下降（p<0.01）;抑制小白菜根系生长的Se(Ⅳ)含量为60 mg·kg-1,明显高于Se(Ⅵ)含量（20.0 mg·kg-1）.相同硒含量下,Se(Ⅳ)处理的小白菜地上部干重为Se(Ⅵ)的1.1~3.0倍,说明本试验条件下Se(Ⅵ)的生物有效性和毒性均大于Se(Ⅳ).Se(Ⅵ)处理小白菜地上部分的硒含量显著高于地下部分,而Se(Ⅳ)处理小白菜地下部分的硒含量显著高于地上部分,小白菜地上和地下部分对Se(Ⅵ)的吸收量均显著高于Se(Ⅳ).综合生长和生理因子分析表明,地上部分生物量是反映Se(Ⅳ)及Se(Ⅵ)处理土壤上小白菜生长状况的理想指标.     

Inorganic nitrogen removal of toilet wastewater with an airlift external circulation membrane bioreactor

Removal of inorganic nitrogen (inorganic-N) from toilet wastewater, using a pilot-scale airlift external circulation membrane bioreactor (AEC-MBR) was studied. The results showed that the use of AEC-MBR with limited addition of alkaline reagents and volumetric loading rates of inorganic-N of 0.19-0.40 kg inorganic-N/(m3·d) helped achieve the desired nitrification and denitrification. Furthermore, the effects of pH and dissolved oxygen (DO) on inorganic-N removal were examined. Under the condition of MLSS at 1.56-2.35 g/L, BOD5/ammonia nitrogen (NH/-N) at 1.0, pH at 7.0-7.5, and DO at 1.0-2.0 mg/L, the removal efficiencies of NH4 -N and inorganic-N were 91.5% and 70.0%, respectively, in the AEC-MBR. The cost of addition of alkaline reagent was approximately 0.5-1.5 RMB yuan/m3, and the energy consumption was approximately 0.72 kWh/m3 at the flux of 8 L/(m2·h).     

Role of water chemistry on estrone removal by nanofiltration with the presence of hydrophobic acids

Hydrophobic acid organic matter (HpoA) extracted from treated effluent has been known to improve the rejection of steroid hormone estrone by reverse osmosis (RO) and nanofiltration (NF) membranes. In this study, the effects of solution chemistry (solution pH and ionic strength) on the estrone rejection by NF membrane with the presence of HpoA were systematically investigated. Crossflow nanofiltration experiments show that the presence of HpoA significantly improved estrone rejection at all pH and ionic strength levels investigated. It is consistently shown that the “enhancement effect” of HpoA on estrone rejection at neutral and alkaline pH is attributed to the binding of estrone by HpoA macromolecules via hydrogen bonding between phenolic functional groups in feed solutions, which leads to an increase in molecular weight and appearance of negative charge. The membrane exhibited the best performance in terms of estrone rejection at pH 10.4 (compared to pH 4 and pH 7) as a result of strengthening the electrostatic repulsion between estrone and membrane with the presence of HpoA. At neutral pH level, the ability of HpoA macromolecules to promote estrone rejection became stronger with increasing ionic strength due to their more extended conformation, which created more chances for the association between estrone and HpoA. The important conclusion of this study is that increasing solution pH and salinity can greatly intensify the “enhancement effect” of HpoA. These results can be important for NF application in direct/indirect potable water reuse.     

Evaluation of the use of bioaccumulation and biological effects tools in caged mussels,within the European Water Framework Directive

Bioaccumulation and biological effects of pollution were assessed in mussels (Mytilus galloprovincialis) caged for one month at three sites in the Oiartzun estuary (south-eastern Bay of Biscay, Spain) with the aim of evaluating their usefulness within the investigative monitoring defined in the European Union Water Framework Directive (WFD). The highest concentrations of organic contaminants determined in mussels' tissue were detected towards the inner part of the estuary but no gradient pattern was found for metal bioaccumulation. Population fitness responses measured as condition index, stress on stress and gonad index were similar in all caged mussels and did not follow the organic pollution gradient. However, biomarkers determined at tissue, cell and protein level (histopathology, micronuclei frequency, malondialdehyde levels and vitellogenin-like protein levels) revealed a higher stress syndrome at the inner part of the estuary showing signs of genotoxicity, oxidative stress and endocrine disruption. Overall, the integrated chemical–biological approach in connection with mussel caging technique proved to be a useful tool to assess environmental pollution, allowing a better understanding of the cause–effect relationship within the investigative monitoring defined in the WFD.     

Potential Negative Ecological Effects of Corridors

Despite many studies showing that landscape corridors increase dispersal and species richness for disparate taxa, concerns persist that corridors can have unintended negative effects. In particular, some of the same mechanisms that underlie positive effects of corridors on species of conservation interest may also increase the spread and impact of antagonistic species (e.g., predators and pathogens), foster negative effects of edges, increase invasion by exotic species, increase the spread of unwanted disturbances such as fire, or increase population synchrony and thus reduce persistence. We conducted a literature review and meta‐analysis to evaluate the prevalence of each of these negative effects. We found no evidence that corridors increase unwanted disturbance or non‐native species invasion; however, these have not been well‐studied concerns (1 and 6 studies, respectively). Other effects of corridors were more often studied and yielded inconsistent results; mean effect sizes were indistinguishable from zero. The effect of edges on abundances of target species was as likely to be positive as negative. Corridors were as likely to have no effect on antagonists or population synchrony as they were to increase those negative effects. We found 3 deficiencies in the literature. First, despite studies on how corridors affect predators, there are few studies of related consequences for prey population size and persistence. Second, properly designed studies of negative corridor effects are needed in natural corridors at scales larger than those achievable in experimental systems. Third, studies are needed to test more targeted hypotheses about when corridor‐mediated effects on invasive species or disturbance may be negative for species of management concern. Overall, we found no overarching support for concerns that construction and maintenance of habitat corridors may result in unintended negative consequences. Negative edge effects may be mitigated by widening corridors or softening edges between corridors and the matrix. Other negative effects are relatively small and manageable compared with the large positive effects of facilitating dispersal and increasing diversity of native species. Efectos Negativos Potenciales de los Corredores     

上海港对间接腹地经济的作用研究——基于资本路径和物流路径

资本流和物流作为海港对间接腹地经济作用的载体,可以根据其作用路径进行详细分析。通过尝试性地建立面板数据模型,分析海港资本作用枢纽—物流园区、支线港和无水港对间接腹地经济的影响,结合海港对作用枢纽的影响力算法,研究得出上海港通过资本路径对间接腹地生产总值的产出弹性为0.058 6。通过物流路径的系统动力学分析对SD流图进行描述,结合Eviews软件设定各要素的数学方程,选择上海港进行仿真分析,并用历史数据对模型进行检验,误差在可接受的范围之内。进一步对系统进行短期预测,结合预测的结果发现货物运输对间接腹地经济作用的弹性约为0.7。最后分别对上海港主要的吞吐货种进行系统仿真,发现集装箱和石油、天然气及制品的物流运输对间接腹地经济影响最大。     

Health and environmental assessment of mercury exposure in a gold mining community in Western Mindanao, Philippines

The small-scale gold mining activities using mercury began in the late 1980s in Sibutad, Western Mindanao. It is located very near the Murcielagos Bay with tailing ponds directly discharging into bodies of water. This cross-sectional study aimed to determine the health and environmental effects of gold mining activities on the community. Residents were randomly selected and classified into two groups, namely, the directly exposed and indirectly exposed populations using a set inclusion criteria. Complete medical and laboratory examinations were performed. Environmental and biologic samples were collected for total mercury and methylmercury determinations. The results showed that the directly exposed group had significantly higher mean blood total mercury and methylmercury levels in comparison with the indirectly exposed population. Although there were no significant differences between hair total mercury and methylmercury levels, there was a trend for higher levels of these biomarkers among the directly exposed residents as compared with the unexposed group. The absence of statistically significant differences may be attributable to the small sample size. Ambient air quality monitoring for mercury exceeded the allowable levels. However, levels of mercury in drinking water and sediments were within allowable limits. Frequency of gastrointestinal complaints was significantly associated with elevated hair methylmercury levels (p=0.02). Also, there appears to be a trend towards higher blood total mercury levels and frequency of gastrointestinal complaints (p=0.09). An interesting finding in this study was the increasing incidence of elevated diastolic blood pressure with elevated hair total mercury levels (p=0.07). Mercury storage at home is a risk factor.     

Thermal decomposition mechanism of 65% lysine sulfate powder and its thermal stability based on thermal analysis

Lysine is widely used in the fields of food, medicine and feed, which generally appears in the form of lysine sulfate or lysine hydrochloride dust because of the high instability of the free L-lysine. The L-lysine Sulfate is in high risk of decomposition, spontaneous ignition and even the dust explosion, because the control temperature in its production process is high up to 90 °C. Thus, the thermal behaviors and its thermal stability of 65% lysine sulfate are experimentally explored in Air and Nitrogen using the simultaneous TG-DSC measurements. Results show: (1) the decomposition of 65% lysine sulfate can be divided into three stages both in the atmospheres of air and nitrogen, and most of the weight loss occurred in the first two stages, which are related with the decarboxylation and deamination process. (2) The effects of atmosphere on the decomposition of 65% lysine sulfate mainly occur at the third stage. In this stage, the weight loss in nitrogen is only 14.2%, which is much lower than that in air (34.3%), which is related to the oxidative degradation at high temperature. Besides, the active energy is slightly increased in nitrogen compared to that in air. (3) The initial temperatures of the decomposition of the 65% lysine sulfate are 145 °C and 155 °C, for the air and nitrogen atmosphere, respectively, which are much lower than that (260 °C) of the pure lysine.     

莱特生物强化技术处理高浓度有机废水的中试

采用莱特生物强化技术(LTBR—Littoral BioReactor),对兰州石化公司化工园区高浓度有机废水进行了中试试验,进行了正常运行的常规标定、水量冲击标定、浓度冲击标定。结果表明:采用LTBR生物处理工艺,使用特效微生物和营养基质,可以在高COD、高含盐等不利条件下正常进行有机物降解,达到了必须将废水中的COD降至2000mg/L以下的试验要求,为处理高浓度有机化工废水的工程应用开辟了新思路。