Destruction of halogen-containing pesticides by means of detonation combustion

Pesticides that contain a halogen functional group have been destructed by means of detonative combustion. The following compounds were examined: (1) atrazine—2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine—herbicide; (2) bromophos—O,4-bromo-2,5-dichlorophenyl O,O-dimethyl phosphorothioate—insecticide; (3) chloridazon—5-amino-4-chloro-2-phenylopyridazin-3(2H)-one—herbicide; (4) linuron—3-(3,4-dichlorophenyl)-1-metoxy-1-methylurea—herbicide; (5) metoxychlor—1,1,1-trichloro-2,2-bis(4-metoxyphenyl)ethane—insecticide and acaricide; and (6) trichlorfon—dimethyl 2,2,2-trichloro-1-hydroxyethylphosphonate—insecticide. Explosive material has been produced on the basis of ammonium nitrate, which served as an oxidizer while the pesticides were used as fuels. Composition of the explosive was adjusted in such a way as to respect thermodynamic parameters. Detonative decomposition of the mixtures has been carried out in shot-holes pre-drilled in soil. Efficiency of the pesticide decomposition has been examined with gas chromatography in order to determine pesticides residues in the environment. It was found that for some, the amount of pesticides in some compounds in the analyzed samples after decomposition was below the determination threshold of the applied method.     

Filtration of Airborne Particulates by Gravel Filters: I. Initial Collection Efficiency of a Gravel Layer

An equation derived for initial collection of efficiency E₀ of a gravel bed filter predicts that — ln(1 — E₀) is proportional to the thickness of the gravel layer, to the — 5/3 power of the diameter of uniform gravels, and to the — 2/3 power of the Darcy airflow velocity. The experimental data obtained from NH₄CI fume removal from dry air at room temperature by sieved gravel fractions generally supported the equation, except that the effect of mean gravel size was represented by the —1.43 power of the average diameter.     

State Standards,Regulations, and Responsibilities in Noise Pollution Control

In the near future the State of Minnesota will adopt noise pollution standards and regulations based on the findings presented in this paper. Comprehensive noise standards are presented for all sources of noise, including airports, highways, and industrial sources. Two of the three dimensions of noise—intensity and frequency—are measured by the use of the unit dBA, whereas the third dimension—duration—is measured by use of the temporal distribution, expressed as L_x, where x is the sound pressure level in dBA exceeded x% of the time. Standards are established for five zones: 1. residential—single family, 2. residential— apartments, public buildings, 3. commercial, 4. manufacturing, and 5 industrial. The L_x standards apply to most noises including industrial and highway noises. Aircraft noise and impulse noise standards are also discussed. The six phase implementation plan for noise abatement is discussed.     

Distribution and human health risk assessment of PAHs in four fish species from a SW Atlantic estuary

Environmental Science and Pollution Research - The aim of this study is to assess—for the first time—the concentration of the 16 polycyclic aromatic hydrocarbons (PAHs) in the muscle...     

Offsetting impacts of development on biodiversity and ecosystem services

Ambio - Offsetting—trading losses in one place for commensurate gains in another—is a tool used to mitigate environmental impacts of development. Biodiversity and carbon are the most...     

Formaldehyde emission—Comparison of different standard methods

The emission of formaldehyde is an important factor in the evaluation of the environmental and health effects of wood-based board materials. This article gives a comparison between commonly used European test methods: chamber method [EN 717-1, 2004. Wood-based panels—determination of formaldehyde release—Part 1: formaldehyde emission by the chamber method. European Standard, October 2004], gas analysis method [EN 717-2, 1994. Wood-based panels—determination of formaldehyde release—Part 2: formaldehyde release by the gas analysis method, European Standard, November 1994], flask method [EN 717-3, 1996. Wood-based panels—determination of formaldehyde release—Part 3: formaldehyde release by the flask method, European Standard, March 1996], perforator method [EN 120, 1993. Wood based panels—determination of formaldehyde content—extraction method called perforator method, European Standard, September 1993], Japanese test methods: desiccator methods [JIS A 1460, 2001. Building boards. Determination of formaldehyde emission—desiccator method, Japanese Industrial Standard, March 2001 and JAS MAFF 233, 2001] and small chamber method [JIS A 1901, 2003. Determination of the emission of volatile organic compounds and aldehydes for building products—small chamber method, Japanese Industrial Standard, January 2003], for solid wood, particleboard, plywood and medium density fiberboard.The variations between the results from different methods can partly be explained by differences in test conditions. Factors like edge sealing, conditioning of the sample before the test and test temperature have a large effect on the final emission result. The Japanese limit for F **** of 0.3 mg l⁻¹ (in desiccator) for particleboards was found to be equivalent to 0.04 mg m⁻³ in the European chamber test and 2.8 mg per 100 g in the perforator test. The variations in inter-laboratory tests are much larger than in intra-laboratory tests; the coefficient of variation is 16% and 6.0% for the chamber method, 25% and 3.5% for the gas analysis method and 15% and 5.2% for the desiccator method.     

Nuclear power in the 21st century: Challenges and possibilities

The current situation and possible future developments for nuclear power—including fission and fusion processes—is presented. The fission nuclear power continues to be an essential part of the low-carbon electricity generation in the world for decades to come. There are breakthrough possibilities in the development of new generation nuclear reactors where the life-time of the nuclear waste can be reduced to some hundreds of years instead of the present time-scales of hundred thousand of years. Research on the fourth generation reactors is needed for the realisation of this development. For the fast nuclear reactors, a substantial research and development effort is required in many fields—from material sciences to safety demonstration—to attain the envisaged goals. Fusion provides a long-term vision for an efficient energy production. The fusion option for a nuclear reactor for efficient production of electricity has been set out in a focussed European programme including the international project of ITER after which a fusion electricity DEMO reactor is envisaged.     

Emergency Planning and Community Right-to-Know

The Emergency Planning and Community Right-to-Know law is an exciting new approach to environmental protection. It is based on the belief that the more information citizens have about environmental conditions in their communities, the better equipped they will be to insure their own protection from unacceptable risks to their health and safety. The law requires disclosure by industry of both the presence and release into the environment—including both accidental and “routine” releases—of hazardous substances. The information will be available not only to government regulators, but also to the people most directly affected—the residents of the communities where the substances are located.     

Modeling the emissions of a dual fuel engine coupled with a biomass gasifier—supplementing the Wiebe function

There is a growing market demand for small-scale biomass gasifiers that is driven by the economic incentives and the legislative framework. Small-scale gasifiers produce a gaseous fuel, commonly referred to as producer gas, with relatively low heating value. Thus, the most common energy conversion systems that are coupled with small-scale gasifiers are internal combustion engines. In order to increase the electrical efficiency, the operators choose dual fuel engines and mix the producer gas with diesel. The Wiebe function has been a valuable tool for assessing the efficiency of dual fuel internal combustion engines. This study introduces a thermodynamic model that works in parallel with the Wiebe function and calculates the emissions of the engines. This “vis-à-vis” approach takes into consideration the actual conditions inside the cylinders—as they are returned by the Wiebe function—and calculates the final thermodynamic equilibrium of the flue gases mixture. This approach aims to enhance the operation of the dual fuel internal combustion engines by identifying the optimal operating conditions and—at the same time—advance pollution control and minimize the environmental impact.     

Effect of Methanol on Exhaust Composition of a Fuel Containing Toluene,n-Heptane,and Isooctane

This study describes the variations in the chemical composition of the exhaust from a single cylinder engine when up to 25% methanol is added to a fuel blend of toluene, isooctane, and n-heptane. Under fuel-rich conditions, and with increasing methanol concentration, it is observed that unburned fuel and benzene emissions increase, exhaust acetylene remains constant, and propylene, isobutylene, methane, ethylbenzene, and styrene concentrations decrease. As oxygen becomes more available, the effects of methanol are reduced, and at an equivalence ratio of 1.25—excess oxygen now is present—methanol no longer affects the concentration of exhaust hydrocarbons. These observations are explained by the reactions of formaldehyde—an incomplete combustion product of methanol— with alkyl radicals derived from the fuel. The photochemical reactivity of the exhaust is unchanged when up to 15% of methanol is present in the fuel at an equivalence ratio of 0.85, but increases at higher methanol contents because of the increase in unburned toluene in the exhaust.     

聚合硅酸钛铝复合絮凝剂的结构及性能

为了克服有机絮凝剂的二次投加及有毒性的缺点,以硅酸钠、硫酸钛、硫酸铝为原料,制备了聚合硅酸钛铝(PTAS)无机高分子复合絮凝剂处理模拟江水。结果表明,在n(Ti+Al)∶n(Si)=1∶3,n(Ti)∶n(Al)=1∶5,模拟江水pH值为5～9.3,絮凝剂投加量为0.3 mmol/L(以金属离子计)时,PTAS对模拟江水的混凝效果最好,除浊率达到92.5%以上。此外,通过X-射线衍射说明聚硅酸与硫酸铝、硫酸钛不是单纯的原料复合;红外吸收光谱显示钛、铝离子及其水解聚合产物可与共存的聚硅酸生成Si—O—Al键和Ti—O—Si键;激光粒度分析表明PTAS在聚合过程中粒度并没有明显变化,但均比聚硅酸粒径大。     

Natural resources and environmental accounting in the Czech Republic: an overview of methodology and results

This paper describes the main features of the study 'Natural Resources and Environmental Accounting in the Czech Republic' (NREACR), carried out under the Phare programme during 1998—1999. Within the project, five major methodological areas were specified: NAMEA-type accounting; land cover/land use (LC/LU) accounting; abatement cost curves (air—energy, transport and industry; water—agriculture, industry, housing); economic (monetary) appraisal of natural assets; and dynamic modelling and scenario development. The results of the first four modules can be thought of as elements of a policy support databank that can have many uses, including the information inputs needed for national economy scenario modelling aimed at exploring the potentials, constraints and trade-oils in the setting and evaluation of Czech Republic economic and environmental policy. In this paper, an overview is given of the modular approach adopted for economy—environment accounting and of the main results, followed by discussion of the outlook for further work in the field in the Czech Republic and also potentially for other EU Accession countries.     

Implementing Pollution Prevention: Incentives and Irrationalities

Widespread pollution prevention will turn on creative use of incentives, since prevention means decentralized changes in raw materials, products, production processes and disposal practices—in short, new ways of doing business—that are difficult to achieve through information transfer or regulatory mandates alone. But past experience with incentives and the context in which these approaches are used will shape both regulators’ attitudes and industry willingness to respond. Thus the choice of incentive mechanism (s) may well determine the extent to which “prevention” is implemented—as well as the extent to which implementation yields environmentally-sound rather than perverse results. Approaches now being debated could produce such perverse effects by treating recyclables as pollution and assuming all reductions towards zero are equally desirable, regardless of net risks reduced or costs incurred by waste generators. Another alternative— tradeable permits progressively reducing the amount of waste received by disposal facilities—could help agencies think through such consequences, force needed decisions on how much “prevention” of which “pollution” is appropriate, and encourage investment to reduce commercial as well as municipal waste. This alternative implies that the criteria for “appropriate prevention” are reduction in waste needing disposal and in overall environmental impact; that recycling should be equated with source reduction in waste management hierarchies, not placed on a lower rung; and that Air Toxics provisions of the pending Clean Air Act may require some adjustments if prevention is not to be aborted by the threat that voluntary reduction steps will become national requirements, for existing sources as well as new ones.     

Accurate Chemical Analysis of MTBE in Environmental Media

The new millennium ushers in changes for refiners of automobile gasoline in the United States, as well as for the state and federal regulators who establish guidelines for gasoline formulation and environmental regulation governing the fate of gasoline-related chemicals in the nation's air, soil and groundwater. One current issue in the gasoline formulation debate centers on the comparison of the proven benefits of the addition of chemical oxygenates—especially methyltert -butyl ether (MTBE)—to gasoline (to improve tailpipe emission quality) against the presumed environmental problems caused by the presence of oxygenates in ground- and surface waters due to fugitive releases of gasoline. Credible debate on this subject presumes that current and past environmental monitoring data for MTBE in environmental samples is accurate and precise. Experience suggests that this assumption is not correct, in part because certain analytical methodologies—particularly older methods supported by the U.S. Environmental Protection Agency—can fall short of reasonable data quality goals for measurement of MTBE. This Technical Note summarizes the standard EPA methods available to site investigators who need to measure MTBE in environmental media, the limitations and advantages of these measurement techniques, and recommendations for improving these standard EPA methods to yield the highest quality MTBE environmental residue data.     

Assessment of Changes in Reported TRI Releases and Transfers Between 1989 and 1990

This study presents results of the first statistically designed study to determine reasons for reported Toxic Release I nventory (TRI) releases and transfers changing from year to year. Data for the study were collected through telephone interviews with a stratified random sample of 1,206 facilities. Each facility was asked to explain the extent to which three factors — source reduction, production fluctuation, and measurement change — contributed to reported changes in TRI releases and transfers between 1989 and 1990. Participants’ responses were weighted and estimates of the reasons for change were calculated for industry and national levels. The results show that source reduction had the greatest impact on net quantity change — at least 45 percent of the total net reductions. However, all three variables contributed to both increases and decreases in releases and transfers. Therefore, comparing the aggregated results of each variable can be difficult since the true effect of each variable may be masked by quantity increases and decreases which have canceled each other out.     

The Utilization of Optimum Meteorological Conditions for the Reduction of Los Angeles Automotive Pollution

Advantage can be taken of optimum conditions of turbulent mixing to decrease the intensity of automobile-caused pollution in the Los Angeles Basin. Changing the summertime peak traffic hours—delaying the morning rush by one hour—will result in an improvement of 24 percent for an eight-hour day, in terms of oxidant concentrations. Greater improvements (up to 54 percent) are possible by use of seven or six-hour days, should they be found to be economically feasible.     

Effect of low-density polyethylene on smoke emissions from burning of simulated debris piles

Low-density polyethylene (LDPE) plastic is used to keep piled debris from silvicultural activities—activities associated with development and care of forests—dry to enable efficient disposal by burning. The effects of inclusion of LDPE in this manner on smoke emissions are not well known. In a combustion laboratory experiment, 2-kg mixtures of LDPE and manzanita (Arctostaphylos sp.) wood containing 0, 0.25, and 2.5% LDPE by mass were burned. Gaseous and particulate emissions were sampled in real time during the entire flaming, mixed combustion phase—when the flaming and smoldering phases are present at the same time—and during a portion of the smoldering phase. Analysis of variance was used to test significance of modified combustion efficiency (MCE)—the ratio of concentrations of fire-integrated excess CO₂ to CO₂ plus CO—and LDPE content on measured individual compounds. MCE ranged between 0.983 and 0.993, indicating that combustion was primarily flaming; MCE was seldom significant as a covariate. Of the 195 compounds identified in the smoke emissions, only the emission factor (EF) of 3M-octane showed an increase with increasing LDPE content. Inclusion of LDPE had an effect on EFs of pyrene and fluoranthene, but no statistical evidence of a linear trend was found. Particulate emission factors showed a marginally significant linear relationship with MCE (0.05 < P-value < 0.10). Based on the results of the current and previous studies and literature reviews, the inclusion of small mass proportions of LDPE in piled silvicultural debris does not appear to change the emissions produced when low-moisture-content wood is burned. In general, combustion of wet piles results in lower MCEs and consequently higher levels of emissions.

Implications:Current air quality regulations permit the use of burning to dispose of silvicultural piles; however, inclusion of low-density polyethyelene (LDPE) plastic in silvicultural piles can result in a designation of the pile as waste. Waste burning is not permitted in many areas, and there is also concern that inclusion of LDPE leads to toxic air emissions.     

Review on Fate,Toxicity, and Remediation of Perchlorate

Several issues regarding the adverse impacts of the chemical—perchlorate—have been identified recently. Perchlorate is a persistent chemical, and remains in water and soil, thereby accumulating in plants and animals. Fetuses suffer the most from perchlorate contamination. There are ongoing debates about the impacts, toxicity and health effects of perchlorate. Many studies have been conducted on its ecotoxicity and its effects, but standards do not exist for perchlorate. This study aims to review the sources, impacts, fate, transport and remediation of perchlorate.     

Sulfur Dioxide Removal and Recovery from Pulp Mill Power Plants

The use of soda ash liquor to scrub SO₂ rich power plant flue gases was studied using an Airetron pilot scrubber with a maximum capacity of 3000 cfm. The relative effects of the major operating variables— temperature, soda ash concentration, and the gas/liquid flow ratio—on the absorption phenomenon were determined. Orthogonal factorial experiments were used to derive a response function relating mass transfer values to operating variables. The economics of a full scale NSSC installation are discussed.     

ESP Bus Section Failures: Design Considerations

This paper addresses a common operation and maintenance problem encountered with sectionalized electrostatic precipitators—bus section failure. ESPs are normally designed to meet a specific minimum collection efficiency in order to comply with emission standards; the loss of several bus sections may cause the unit to be out of compliance. In this paper, the effect of bus section failure on precipitator performance is analyzed. The study is presented in two parts. First, a simplified procedure to estimate the effect of bus section failure on the overall collection efficiency is developed. An illustrative example is presented to demonstrate the use of the technique. Secondly—and this is the main thrust of this study—the technique is extended to include calculations on whether a unit is out of compliance due to the failure of a given number of bus sections. This development clearly shows that this latter effect can only be expressed in terms of a probability. Two additional examples, based on a field unit using actual test data, complement the presentation and illustrate this probability calculation.