Exposure,epidemiology, and mechanism of the environmental toxicant manganese

It has become increasingly apparent that global manganese (Mn) pollution to air and water is a significant threat to human health. Despite this recognition, research is only beginning to comprehend the detrimental effects of exposure. Mn, while essential, is particularly harmful to the central nervous system, and overexposure is symptomatic of several neurological disorders. At-risk populations have been identified, but it is still unclear whether typical exposure levels have any long-term consequences. Those at an elevated risk have diminished intellectual function, learning and memory, and mental development. While the overall mechanism of toxicity is undetermined, Mn has been found to induce oxidative stress, exacerbate mitochondrial dysfunction, dysregulate autophagy, and promote apoptosis, ultimately enhancing neurodegeneration. Extrapolation of this in vitro and in vivo data to humans is difficult. There is a definite need to correlate epidemiological studies with causative effects. It is imperative that research efforts endure, so threats are appropriately identified and exposure properly regulated.     

好氧颗粒污泥的特点及其研究进展

综述了好氧颗粒污泥的基本特征和微生物相、好氧颗粒污泥形成的主要影响因素及其颗粒化反应器等。好氧颗粒污泥是近几年发现的在好氧条件下自发形成的细胞自身固定化过程 ,是生物膜特殊的生长形式。颗粒污泥具有良好的沉降性能、较高的生物量和在高容积负荷条件下降解高浓度有机废水的良好生物活性。污泥颗粒化过程是一个多阶段的过程 ,取决于废水组成及其操作条件的选择。在气提式内循环间歇反应器 (internalcirculatesequencingbatchairliftreac tor ,ICSBAR )中易于培养出性能良好的好氧颗粒污泥。     

绿色絮凝剂PAS的性能及混凝机理探讨

通过向聚硅酸中加入一种高价亲生物环保的金属离子Ti⁴⁺,制备了一种适合处理长江水的绿色絮凝剂PAS,并且通过实验确定了其处理长江水的最佳处理条件：酸性聚硅酸与Ti金属盐溶液复合,n_Ti/n_Si=0.3;投加量为10 mg/L（以Ti⁴⁺计）,pH=6～8,UV254的去除率＞61.7％,浊度去除率＞99％。PAS的混凝效果明显优于聚合铝和聚硅铝,而且矾花形成迅速,絮体密实、沉降快、出水更加清澈,无残留铝。Ti也是亲生物金属,健康环保。因此,PAS是绿色环保友好型絮凝剂,可作为饮用水专用絮凝剂。观察所形成絮体的形貌以及观测红外光谱图均发现,絮凝剂对胶体颗粒污染物有较好的架桥网捕与络合反应作用。     

污泥龄对LSP & PNR污泥减量新工艺运行效能的影响

通过研究分析污泥龄（SRT）对富磷污水除磷的LSP&PNR污泥减量新工艺运行效果的影响,结果发现,延长污泥龄有利于提高系统的厌氧释磷能力,但不影响其总的除磷率,同时磷的回收比例增大,当SRT=50 d时,磷回收率取得最大值70.4％;LSP&PNR系统污泥龄增加,还有利于污泥产率的降低。试验还发现,排富磷污水除磷的长污泥龄LSP&PNR系统的除磷效率与污泥产率之间不存在制约关系,即系统可以同时获得优异的污泥减量与生物除磷效果,当SRT=50 d时,每降解1 kg COD仅产生0.143 kg污泥,而除磷率达最高值928％;LSP&PNR系统中SRT、DO与SVI之间存在一定的相关性,在供氧充足（DO＝0.8～1.5 mg/L）条件下,SRT增加,SVI越高,但对于SRT为50 d的LSP&PNR系统,稳定运行时没有污泥膨胀之虞。     

MBR工艺处理含50%海水的污水试验研究

采用MBR工艺对含50%海水的污水生物处理进行了试验研究。实验条件为进水COD为300～2 600 mg/L,NH₃-N为50～300 mg/L,pH值为6～9,混合液污泥浓度为7 000 mg/L,溶解氧浓度为2～4 mg/L,温度为20～25℃。试验结果表明,系统的最佳运行条件为：有机负荷＜3.2 kg COD/（m³·d）,氨氮负荷＜0.35 kg/（m³·d）,pH值在7.5～8.5之间,HRT＞12 h。在此条件下,COD与氨氮的去除率可同时达到90%。高盐环境下微生物所分泌的大量胞外多聚物是造成MBR工艺处理含盐废水过程中膜污染的主要原因。     

半干法烟气脱硫新技术——粉末-颗粒喷动床技术

粉末 颗粒喷动床 (powder particlespoutedbed ,PPSB)是近几年来由日本研究人员开发的一种新的半干法烟气脱硫技术。本文介绍了PPSB的基本原理、优点以及在试验条件下所得到的影响因素和适宜的运行方式。PPSB在系统结构、废物处理、操作和费用方面比湿法有所提高 ,同时又比干法和其他半干法的去除率和吸收剂的利用率高。此外 ,对吸收剂研究结果表明 ,石灰石的脱硫效率虽然不及石灰 ,但是由于PPSB中吸收剂的停留时间长 ,气、固、液三相接触好的特点以及可以对石灰石进行研磨 ,因此 ,利用石灰石作吸收剂的PPSB完全可以达到理想的脱硫效率 ,同时也可以保持较好的经济性。但是 ,目前还没有大规模的试验和应用。所以PPSB是一项十分值得进一步开发和应用的烟气脱硫新技术。     

铁炭微电解-MAP沉淀法联合预处理垃圾渗滤液

采用铁炭微电解-磷酸氨镁(MAP)沉淀法对垃圾渗滤液进行预处理,实验结果表明,铁炭比为5∶1,pH值为3,反应时间为3 h时,铁炭微电解的COD的去除率为47.5%;在投加药剂n(Mg2+)∶n(PO43-)∶n(NH4+)为1.4∶1∶1,pH值为9,反应时间为1 h的条件下,垃圾渗滤液氨氮去除率达到79.7%。     

污泥淤砂分离器对分离分流污泥性质的影响

为解决我国很多城镇污水厂活性污泥的MLVSS/MLSS普遍偏低,污泥中泥沙淤积严重的问题,根据水力旋流器的分离原理,开发了污泥淤砂分离器,实现污泥中生物基质和淤砂的分离分流,研究污泥淤砂分离器主要结构参数排口比(底流口直径/溢流管直径)对分离分流污泥性质的影响。实验结果表明,排口比为0.4时,污泥经过污泥淤砂分离器后,得到的底流污泥MLVSS/MLSS比原污泥减小了34%,溢流污泥MLVSS/MLSS增大了16.8%,污泥中的生物基质富集在溢流污泥中,淤砂富集在底流污泥中;底流污泥浓度MLSS比原污泥增加了2.6倍,底流污泥SVI和CST分别减小了68%和70%,底流污泥浓缩效果明显,沉降性能和脱水性能大幅提高,有利于底流污泥的处理处置;进一步减小排口比,底流污泥浓缩效果、沉降性能和脱水性能均进一步提高。     

贝壳粉型煤固硫剂固硫的实验及机理研究

以贝壳粉作为型煤固硫剂,用正交实验的方法研究了影响贝壳粉固硫率的主要影响因素,在高温(1 150℃)时固硫效率达到56.6%,比CaCO3的固硫率提高40%以上,具有较好的高温固硫性。分析得知,贝壳的主要成分为CaCO3,其含钙量在40%左右,贝壳中又含有较高的Na等碱金属元素以及Fe,Al和Si等。用X射线粉末衍射法分析了高温(1 150℃)型煤样生成的灰渣,分析了贝壳粉作为型煤固硫剂在高温下具有较高固硫率的机理。发现CaAlSi2O8为主的复合晶体在高温下包裹在CaSO4的表面,抑制了CaSO4的热分解从而有效地提高了固硫率。     

巢湖湖岸砂石的磷吸附特性研究

以巢湖湖岸上富含铁、铝、锰等元素的砂石为实验材料,研究其对水体中磷的吸附效果。实验表明:在砂石对磷的吸附过程中,同时存在着物理吸附和化学吸附,且以化学吸附作用为主,符合准二级动力学模型;砂石对磷的作用与溶液初始磷浓度有关,磷释放与吸附的临界浓度点约为0.04 mg/L;砂石对磷的吸附符合Langmuir等温吸附方程,最大吸附量约为1 428.57 mg/kg,对磷的吸附效果比普通沙石要好,且经济易得。     

磁流体处理印染废水初探

探讨了Fe3O4磁流体在不同条件下对降低印染废水的COD和色度两个方面的影响，实验表明，当pH=11，十二烷基叔胺的量是亚铁量的0．16倍时，COD降低最多，脱色效果最好，且磁场强度在160mT左右时，磁流体沉降最快。     

A novel method for measuring the evaporation of contaminant liquids from sands

A novel experimental system, electrodynamic levitation, is used to measure the evaporation of liquids from microparticles of sand. The levitator is used to measure the evaporation rate of diethylphthalate (DEP) from microparticles of Saudi Arabian sand at 1 atm pressure and 25 degrees C. Evaporation experiments were conducted for both inland- and coastal-sand microparticles, the diameter of which is 50 microm. The DEP-evaporation rate is determined from gravimetric changes in the DEP-sand-mixture particle, the weight of which is directly proportional to the levitating electric-field intensity. From telemicroscopical observations, it is found that, when the sand particle is enclosed in DEP liquid, the sand-DEP-mixture particle evaporates like a pure DEP droplet. However, when sufficient DEP liquid has evaporated and the DEP is adsorbed into the sand microparticle, the DEP evaporation rate is reduced by a factor of 3-5 as compared with a pure DP droplet.     

Optimal design of predenitrification systems.

A coupled model of biological and settling phases aimed at optimal design of predenitrification systems is presented. Each unknown is obtained in explicit form, and is expressed as a function of the system's required performance. A model, taking into account both suspended and dissolved substrates, is adopted for the biological phase, while the limiting solid flux theory is assumed for the design of the settling phase. Finally, a relationship correlating the two phases is obtained expressing opportunely the sludge recycle flow and the sludge waste flow, without recourse to empirical parameters. The effect of different influent and effluent wastewater characteristics on the model's results is also analyzed.     

盐液浸提辅助微波再生废油脱水树脂及机制分析

对用于废油脱水的聚丙烯酸钠树脂在盐液浸提辅助微波脱附再生过程中的脱附特性和再生使用性能进行了研究。实验结果表明,盐液浸提辅助微波处理的脱附速率是普通热处理的5～6倍,且能耗更低,脱附率更高,树脂床层温升速率更快,温度峰值却更低,说明盐液浸提对微波处理具有明显辅助效果;树脂再生性能测试结果表明,盐液浸提辅助微波处理的树脂再生使用性能最好,孔结构破坏更少。分析认为,微波选择加热特性以及盐液浸提导致树脂内外渗透压降低和方向改变是盐液浸提辅助微波处理具有良好脱附效果的关键机制。     

The Annual Average: An Alternative to the Second Highest Value as a Measure of Air Quality

It is common practice to use the second highest value both in determining compliance with the once-per-year air quality standards (AQS) and as a measure of air quality in pollutant trend studies and rollback calculations. A study of the variation in the second highest 8 hr carbon monoxide concentration observed at the CAMP stations 1962-72 is presented. It is shown that, for a given annual average, the second highest value can differ by a factor of 2 due to random variation. The annual average is linearly related to the observed average of the second highest value and is shown to be a good predictor of the percent of time the carbon monoxide AQS is exceeded. It is concluded that the annual average, which is less variable and not as greatly influenced by erroneous measurements, is the preferred measure of air quality for trend studies and air quality projections.     

Some Factors in Minimizing Precipitator Costs

This paper is directed to those individuals involved in design of electrostatic precipitators. The Deutsch-Anderson model is usually employed by industry for the design of electrostatic precipitators. The so-called process design variable in this approach is the total capture area in the precipitator. Unfortunately, little is available on the equipment design of this unit, i.e., the geometric arrangement of the plates that constitute the capture area and the external dimensions of the physical structure that houses the precipitator components. These are important economic considerations, and it is to this subject that this paper is directed. It is relatively easy to predict equipment costs for “off-the-shelf” electrostatic precipitators; it is more difficult to closely predict the cost for a custom-made unit, which is more often the case encountered in practice. Once the capture area is calculated, the total precipitator cost becomes a strong function of the outer casing and outer accessories of the physical system. In this paper, a model is presented that can help minimize precipitator cost. An illustrative example complements the development of the model.     

Deposition to forests in Europe: most important factors influencing dry deposition and models used for generalisation

Dry deposition of gases and particles to forests is influenced by factors influencing the turbulent transport, such as wind speed, tree height, canopy closure, LAI, etc. as well as by factors influencing surface condition, such as precipitation, relative humidity, global radiation, etc. In this paper, an overview of these factors is given and it is shown which are the most important determining temporal and spatial variation of dry deposition of sodium and sulphur. Furthermore, it is evaluated how well current deposition models are able to describe the temporal and spatial variation in dry deposition. It is concluded that the temporal variation is not modelled well enough, because of limited surface-wetness exchange parameterisations. The influence of forest characteristics are modelled reasonably well, provided enough data describing the forests and the spatial variation in concentration is available. For Europe these data are not available. The means to decrease the atmospheric deposition through forest management is discussed.     

某厂金属铜管加工废气处理方法的研究

我国对于大气污染物的排放给予了高度的重视，规定生产中的污染物必须达标排放。对某厂酸洗车间产生的以酸雾和氮氧化物为主的废气采用高效局部排气罩加以集中收集，设计了净化吸收系统，使经过处理的废气达到“大气污染物综合排放标准”中的二级排放要求，并在设计中充分考虑了系统的节能，收到了良好的环保效果。     

某厂金属铜管加工废气处理方法的研究

我国对于大气污染物的排放给予了高度的重视,规定生产中的污染物必须达标排放。对某厂酸洗车间产生的以酸雾和氮氧化物为主的废气采用高效局部排气罩加以集中收集,设计了净化吸收系统,使经过处理的废气达到“大气污染物综合排放标准”中的二级排放要求,并在设计中充分考虑了系统的节能,收到了良好的环保效果。     

微环境新风量的检测原理及方法研究

新风量是评价室内微环境空气卫生质量的主要卫生指标之一,也是计算室内某种气体单位时间排放量的重要参数。以CO2作为示踪气体,利用于冰升华和人体呼吸产生CO2示踪气体两种测量方法对室内和车内微环境进行了检测,并考虑室内人呼出CO2量的影响,运用箱子模式的各种推导公式（稳态法、解析解法和差分法）对新风量进行了计算,并对结果进行了讨论。结果表明,没有人存在下,用箱子模式的解析解法和差分法计算的新风量值没有明显的统计差异;微环境内有人时必须考虑人释放的影响,这样箱子模式的各种推导公式都可以计算新风量值,且结果准确,准确度高。利用人体呼吸产生CO2示踪气体法,用差分法计算结果不理想,偏差很大;用稳态法计算重现性高,结果可靠。