Optimization of Flow for Forcing Stack Wastes to High Altitudes

It is difficult to control the emission of waste products from large stacks because of the large volume of material to be handled. However, if the waste gas is projected to relatively high altitudes, the problem is less severe in that pollution products are carried to regions of low pollution density. It is especially helpful to accomplish this high altitude dispersal during periods when the air is stable and pollution buildup is most severe. In this paper it is shown that dramatic improvements in the altitude to which stack wastes rise may be obtained by emitting the effluent in discrete vortex rings rather than in steady plumes or forced jets. The parameters of vortex rings required to reach given altitudes under given conditions are calculated. The flow at the stack required to give specific vortex ring parameters is also calculated. Some comments on the type of stack needed to create the desired flow are presented.     

不饱和聚酯树脂生产废水治理技术

不饱和聚酯树脂生产废水CODCr高达 10 0 0 0 0mg/L ,pH为 1— 2 ,且排放无规律 ,处理难度大。采用先对缩聚废水进行蒸馏浓缩 ,再真空泵废水混合调质、降温、缺氧水解后 ,经高效的好氧生物处理工艺 (HCR)处理后与低浓度的冲洗水、生活废水混合 ,进行低负荷的生物接触氧化处理 ,出水CODCr稳定在 10 0mg/L以下。     

Cost-Effective Enforcement Of Environmental Standards

The body of information presented in this paper is directed to those individuals concerned with cost-effective enforcement of environmental standards. Its aim is twofold. One is to determine some of the differing impacts upon firm behavior of legal enforcement, of economic incentive enforcement, and of mixed legal-economic enforcement. A second objective is to initiate identification of enforcement systems which are most likely to minimize resource costs to firms and enforcement agencies of meeting environmental standards. A computerized model is used to simulate enforcement of the new source particu-late matter discharge standard for coal-fired power plants. Under current legal enforcement it is found that most plants will violate the standard, that small plants will control to higher removal levels than large plants and that firms will install relatively costly pollution control technology. Three enforcement alternatives are considered for overcoming these shortcomings: more stringent legal enforcement, economic incentive enforcement using effluent taxes, and a mixed system which uses device certification tests and effluent taxes. It is found that each of the alternatives can lead to the standard being met and tc more-or-less equal sharing in control burden across plant size. But it is only the two systems which use effluent taxes that give incentive for choosing least costly control technology. It is concluded that the two enforcement systems which use effluent taxes probably would encourage adoption of least cost control technology. This is likely to be a desirable outcome since it may lead to minimum resource costs to power plants and pollution control agencies of meeting fty ash standards. The general applicability of this conclusion to other enforcement situations is discussed.     

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.     

On the scientific basis for global warming scenarios

The scientific basis for current projections of significant warming due to enhanced minor greenhouse gases in the atmosphere is reviewed. Care is taken to distinguish the issue of changes in radiative forcing at the earth's surface from the issue of the climatic response to this forcing. With respect to the former, it is noted that the predicted forcing is, in fact, small (2 W m(-2) at the surface for a doubling of CO(2), or less than 1% of the absorbed solar flux). With respect to the latter, it is noted that predictions of significant warming are dependent on the presence of large positive feedbacks serving to amplify the response. The largest of these feedbacks in current models involves water vapor at upper levels in the troposphere. This feedback appears to be largely a model artifact, and evidence is presented that models may even have the wrong sign for this feedback. The possibility is examined that the response of climate to major volcanic eruptions may provide a test of the climate system's amplification. The basis for this possibility is the fact that the response delay of the ocean-atmosphere system is proportional to the system gain.     

活性污泥中功能性菌群抗盐度冲击性能研究

利用批量实验研究了活性污泥在受到不同盐度冲击时,其硝化功能、反硝化功能以及生物除磷功能所受到的影响。实验结果表明,活性污泥中亚硝酸菌在氯化钠浓度为10 g/L的环境中,其硝化功能受到86%的的抑制作用;硝酸菌对盐度比亚硝酸菌更敏感,氯化钠浓度为5 g/L时已受到较强的抑制。氯化钠浓度达到50 g/L时,反硝化菌受到46%的抑制作用,反硝化菌对盐度的敏感性比硝化菌低得多。聚磷菌对盐度也很敏感,在氯化钠浓度为20 g/L的环境中,聚磷菌厌氧阶段释磷受到52%的抑制作用;而氯化钠浓度为5 g/L时,好氧阶段吸磷已受到41%的抑制作用。     

Photochemistry and environment IV- Photochemical behaviour of monochlorophenols in dilute aqueous solution

The photochemical behaviour of chlorophenols is different to that of non-halogenated phenols. In the former, the first step is a C-Cl bond scission, which is not influenced by oxygen. Chlorine is converted into hydrochloric acid. For monochlorophenols, the position of the chlorine on the ring strongly influences the transformation. In the molecular form, 2-chlorophenol is converted into pyrocatechol. In the anionic form however, it is reduced in a cyclopentadienic acid which dimerizes according to a Diels-Alder reaction. The irradiation of 3-chlorophenol leads to resorcinol whatever the pH. This would appear to suggest a photohydrolysis mechanism. With 4-chlorophenol, the photochemical conversion is not so specific. Hydroquinone is formed (mainly in aerated solution), along with polyphenolic oligomers. A radical mechanism is proposed.     

Reduction of nitrogen excretion and emission in poultry: A review for organic poultry

Organic poultry is an alternative to conventional poultry which is rapidly developing as a response to customers' demand for better food and a cleaner environment. Although organic poultry manure can partially be utilized by organic horticultural producers, litter accumulation as well as excessive nitrogen still remains a challenge to maintain environment pureness, animal, and human health. Compared to conventional poultry, diet formulation without nitrogen overloading in organic poultry is even more complicated due to specific standards and regulations which limit the application of some supplements and imposes specific criteria to the ingredients in use. This is especially valid for methionine provision which supplementation as a crystalline form is only temporarily allowed. This review is focused on the utilization of various protein sources in the preparation of a diet composed of 100% organic ingredients which meet the avian physiology need for methionine, while avoiding protein overload. The potential to use unconventional protein sources such as invertebrates and microbial proteins to achieve optimal amino acid provision is also discussed.     

Forewarning model for water pollution risk based on Bayes theory

In order to reduce the losses by water pollution, forewarning model for water pollution risk based on Bayes theory was studied. This model is built upon risk indexes in complex systems, proceeding from the whole structure and its components. In this study, the principal components analysis is used to screen out index systems. Hydrological model is employed to simulate index value according to the prediction principle. Bayes theory is adopted to obtain posterior distribution by prior distribution with sample information which can make samples’ features preferably reflect and represent the totals to some extent. Forewarning level is judged on the maximum probability rule, and then local conditions for proposing management strategies that will have the effect of transforming heavy warnings to a lesser degree. This study takes Taihu Basin as an example. After forewarning model application and vertification for water pollution risk from 2000 to 2009 between the actual and simulated data, forewarning level in 2010 is given as a severe warning, which is well coincide with logistic curve. It is shown that the model is rigorous in theory with flexible method, reasonable in result with simple structure, and it has strong logic superiority and regional adaptability, providing a new way for warning water pollution risk.     

基于基尼系数的乌梁素海流域污染负荷分配

在水体污染物总量控制分配中,科学合理地分配污染物排放指标是实施水体环境管理的关键.将应用在经济领域衡量居民收入分配公平程度的基尼系数引入环境领域,提出环境基尼系数这一新概念用于解决流域内各分区污染物总量控制分配的问题.以乌梁素海流域为例,分别以流域内各分区人口、水资源量和国内生产总值(GDP)作为流域内基尼系数的分配指...     

State-space modeling of the relationship between air quality and mortality

A portion of a population is assumed to be at risk, with the mortality hazard varying with atmospheric conditions including total suspended particulates (TSP). This at-risk population is not observed and the hazard function is unknown; we wish to estimate these from mortality count and atmospheric variables. Consideration of population dynamics leads to a state-space representation, allowing the Kalman Filter (KF) to be used for estimation. A harvesting effect is thus implied; high mortality is followed by lower mortality until the population is replenished by new arrivals. The model is applied to daily data for Philadelphia, PA, 1973-1990. The estimated hazard function rises with the level of TSP and at extremes of temperature and also reflects a positive interaction between TSP and temperature. The estimated at-risk population averages about 480 and varies seasonally. We find that lags of TSP are statistically significant, but the presence of negative coefficients suggests their role may be partially statistical rather than biological. In the population dynamics framework, the natural metric for health damage from air pollution is its impact on life expectancy. The range of hazard rates over the sample period is 0.07 to 0.085, corresponding to life expectancies of 14.3 and 11.8 days, respectively.     

Statistical modelling of water colour in the uplands: The Upper Midd catchment 1979-1987

The increasing colour of raw water from the uplands is a matter of concern to water managers. The colour record for the period 1979-1987 is examined for the catchment of Upper Nidderdale, North Yorkshire. The variation in colour shows a marked seasonality with peaks occurring during the autumn months. No long-term sustained increase in colour is found, although colour levels were high in 1980, 1985 and 1987. Colour is found to be highly correlated with iron and, more particularly, aluminium. There is no relationship between colour and turbidity which suggests that there is no direct link between colour levels and erosion on the catchments. Colour increases appear to relate to large soil moisture deficits in months immediately prior to the colour flush and to high soil moisture deficits in the previous year. Complementary relationships are found between monthly rainfall totals and colour. In the light of these findings, it is suggested that high colour is associated with water table lowering and aerobic decomposition of the upper organic peat layers.     

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.     

Macrodispersion by diverging radial flows in randomly heterogeneous porous media

Radial flow takes place in a heterogeneous porous formation where the transmissivity T is modelled as a stationary random space function (RSF). The steady flow is driven by a given rate, and the mean velocity is radial. A pulse-like of a tracer is injected in the porous formation, and the thin plume spreads due to the fluctuations of the velocity which results a RSF as well. Transport is characterized by the mean front, and by the second spatial moment of the plume. We are primarily interested in tracer macrodispersion modelling. With the neglect of pore-scale dispersion, macrodispersion coefficients are computed at the second order of approximation, without neglecting the head-gradient fluctuations. Although transport is non-ergodic at the source, it is shown that ergodicity is achieved at small distances from the source. This is due to the fact that close to the source local velocities are quite large, and therefore solute particles become uncorrelated very soon. Under ergodic conditions, we compare macrodispersion mechanism in radial flows with that occurring in mean uniform flows. At short distances the spreading effect is highly enhanced by the large variability of the flow field, whereas at large distances transport exhibits a lesser dispersion due to the reduction of velocities. This supports the explanation provided by Indelman and Dagan (1999) to justify why the macrodispersivity is found smaller than that pertaining to mean uniform flows. The model is tested against a tracer transport experiment (Fernàndez-Garcia et al., 2004) by comparing the theoretical and experimental breakthrough curves. The accordance with real data, that is achieved without any fitting to concentration values, strengthens the capability of the proposed model to grasp the main features of such an experiment, the approximations as well as experimental uncertainties notwithstanding.     

On spurious water flow during numerical simulation of steam injection into water-saturated soil

Numerical simulation of steam injection into a water-saturated porous medium may be hindered by unphysical behavior causing the model to slow down. We show how spurious water flow may arise on the boundary between a steam zone and a saturated zone, giving rise to dramatic pressure drops. This is caused by the discretization of the temperature gradient coupled with the direct relation between pressure and temperature in the steam zone. The problem may be a severe limitation to numerical modeling. A solution is presented where the spurious water flow is blocked and this widely enhances the performance of the model. This new method is applied to a previously reported example exhibiting numerical problems. Furthermore, it is applied to the simulation of 2-D sandbox experiments where LNAPL is remediated from a smearing zone by steam injection. These experiments would have been difficult to analyze numerically without the adjustment to prevent spurious flow.     

总量控制规划中允许排放量的平权分配

对总量控制规划中公平合理分配各污染源允许排放量的意义以及现有平权分配方法中存在的问题进行分析。阐明了允许排放量平权分配的原则,提出了平权分配污染源允许排放量的Ｂ值法。剖析了分析平权后剩余环境容量的必要性,并提出了相应的解决方法。     

论生态环境监测

通过对生态环境监测，特别是基层生态环境监测体系、现状、监测内容、实施原则等进行了初步探讨，以推动生态环境监测工作的进展。     

ABR反应器的两种快速启动方法对比

ABR反应器的启动是ABR反应器能否高效稳定运行的关键，其影响因素很多。为了更好地实现ABR反应器的启动，提出了通过2种不同启动方法的对比，即1^#反应器采用好氧预挂膜的方法，2^#反应器采用低负荷启动法，得出的结论为，好氧预挂膜启动法的启动时间短，COD去除率高，出水pH稳定，颗粒状污泥生长情况较好，是一种可推广的启动方法。     

Atmospheric pollution transport: the parallelization of a transport & chemistry code

We discuss a model for computing the chemical reactions occurring among air pollutants and predict their dispersion in the atmosphere. We consider a parallel implementation on a CRAY T3D, using up to 128 processors. A regular subdomain decomposition is considered to optimize inter-processor communications, while load balancing – the main technical difficulty to obtain a good efficiency – is achieved by re-assigning temporarily pieces of work to other processors, according to a global strategy. The performance of our implementation is described by an analytical relation whose validity is checked on realistic data sets. A speedup of 100 is obtained with 128 processors.     

The effect of acidification on the accumulation and toxicity of metals to freshwater invertebrates

This paper reviews the literature to determine if lowered water pH (a) affects metal bioaccumulation in freshwater invertebrates, (b) enhances the toxicity of a given metal, and (c) increases waterborne metal concentrations to levels toxic to invertebrates. The elements considered are mercury, lead, cadmium and aluminum. The available evidence suggests that of these elements only mercury is biomagnified in aquatic foodchains. The bioaccumulation of all these elements is influenced by water pH, but data concerning invertebrates is meagre for mercury and lead. The effect of pH on mercury and lead toxicity to invertebrates is unclear and may be largely species specific. Cadmium toxicity is reduced by lower pH, while aluminum toxicity to invertebrates is markedly higher due to changes in aluminum speciation at low pH.