Sulfur dioxide effects on plants exhibiting Crassulacean Acid Metabolism

The effects of SO(2) on species exhibiting Crassulacean Acid Metabolism (CAM) were determined with short term-high concentration 'acute' greenhouse exposures (0.6 to 3.0 microl liter(-1) (ppm) SO(2) for 2 and 8 h), and long term-low concentration 'chronic' field exposures (0.35 to 0.90 microl liter(-1) SO(2) for 32 to 79 h periodically over 7 to 13 days). In the acute greenhouse exposures, visible injury was observed on Opuntia basilaris Engelm. & Bigel., exposed to 2.0 microl liter(-1) SO(2), but no injury was observed on Ananas comosus (L.) Merr., Bryophyllum blossfeldiana Poelln., Bryophyllum pinnata (Lam.) Pers., or Bryophyllum tubiflora (Harv.) Hamet, exposed to up to 2.8 microl liter(-1) SO(2) for 8 h. Stomatal conductance during the exposures averaged 0.067+/-0.021mol(-2)s(-1) for Opuntia basilaris, 0.029+/-0.008mol(-2)s(-1) for Ananas comosus, and 0.029+/-0.008mol m(-2)s(-1) for Bryophyllum pinnata. Opuntia basilaris was injured early during the day, but not at night; with the injury appearing as a white necrotic banding across just fully expanded pads. Moderately injured pads would regreen beginning 1 to 2 weeks after exposure. In chronic field exposures, no visible injury from SO(2) was observed on Opuntia basilaris, Dudleya arizonica Rose or Agave deserti Engelm. plants, grown either with supplemental irrigation or natural rainfall. In addition, in the field SO(2) had no effect on CO(2) uptake, total sulfur content, transpiration, or tissue acidity in either the light or the dark, or in irrigated vs natural rainfall plots.     

燃煤电厂SO3排放特征及其脱除技术

通过现场实测和文献调研相结合的方式,对目前燃煤电厂SO3排放特征进行较全面的表征,排放浓度为0.3~22.7 mg·m-3,按10 mg·m-3和5 mg·m-3排放限值考核,达标率分别为89.8%、66.7%。对现有除尘、脱硫设备及新技术的SO3脱除能力进行定量分析,常规电除尘器对SO3脱除率仅为10%~20%;低低温电除尘技术可达95%以上;电袋复合除尘器可达80%以上;常规石灰石石膏湿法脱硫技术多在30%~60%,采用旋汇耦合、双托盘等技术后,SO3脱除率可达90%以上;金属板式湿式电除尘器多在50%~80%,导电玻钢管式湿式电除尘器多在60%~90%;碱基干粉或溶液喷射技术均可达到80%以上的SO3脱除效果;烟气冷凝相变凝聚技术在消除有色烟羽的同时,也具有一定的SO3脱除效果。根据不同SO3脱除技术对比结果,碱基喷射技术不仅可以实现较高SO3脱除效果,还可有效解决空预器的腐蚀、堵塞等问题,将是未来解决高浓度SO3问题的主流技术方向。     

Sulfur dioxide and nitrogen oxides emissions from U.S. pulp and paper mills, 1980-2005

Comprehensive surveys conducted at 5-yr intervals were used to estimate sulfur dioxide (SO,) and nitrogen oxides (NO.) emissions from U.S. pulp and paper mills for 1980, 1985, 1990, 1995, 2000, and 2005. Over the 25-yr period, paper production increased by 50%, whereas total SO, emissions declined by 60% to 340,000 short tons (t) and total NO, emissions decreased approximately 15% to 230,000 t. The downward emission trends resulted from a combination of factors, including reductions in oil and coal use, steadily declining fuel sulfur content, lower pulp and paper production in recent years, increased use of flue gas desulfurization systems on boilers, growing use of combustion modifications and add-on control systems to reduce boiler and gas turbine NO, emissions, and improvements in kraft recovery furnace operations.     

Systematic error and uncertain carbon dioxide emissions from U.S. power plants

Carbon dioxide (CO₂) emissions from U.S. power plants are independently reported by the U.S. Energy Information Administration (EIA) and the Clean Air Markets Division (CAMD) within the U.S. Environmental Protection Agency (EPA). Differences between the CAMD and EIA emission tallies show that the amount of CO₂ produced by an individual power plant is less certain than might be imagined or desired. These differences are attributed to systematic error and random measurement error. Random error cannot be retroactively corrected, whereas systematic error can be corrected where relevant data are available. Accordingly, this study identified and, where possible, corrected systematic error affecting the CAMD and EIA CO₂ emission tallies for 1065 power plants that emitted more than 25,000 tons of CO₂ during 2013. The EIA tallies were corrected by accounting for emission factor error, acid-gas sorbent consumption, and combustion of biogenic fuel. The CAMD tallies were likewise corrected by accounting for unreported unit emissions. It was not possible to objectively correct systematic error affecting about 11% of the power plants, and subjective corrections were not attempted. At these plants, the CAMD and EIA emission tallies sometimes differed by more than 20% due to missing unit error, plant identification error, temporal measurement error, or inferred reporting error. Comparisons of the CAMD and EIA emission tallies before and after correction for systematic error show the effectiveness of these corrections. The comparisons also show the persistence of random measurement error.

Implications: Understanding the uncertainty of CO2 emission tallies for USA power plants might inform emission inventories, atmospheric flow models or inversions, and emission reduction policies. Knowing the cause and size of measurement errors that contribute to this uncertainty might also help to identify ways to improve the measurement methods and reporting protocols that these CO2 emission tallies are based on.     

Chlorinated fluorenes and alkylfluorenes in bleached kraft pulp and pulp mill discharges

The occurrence and levels of polychlorinated fluorenes (PCFLs), methylfluorenes (C₁-PCFLs) and dimethylfluorenes (C₂-PCFLs) were studied by high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS) in hardwood and softwood pulp, effluent and biosludge from a bleached kraft mill. Semiquantitative concentrations of these compounds were estimated using selected ion monitoring and a mass spectral resolution of 10,000. The identification of PCFLs and C₁-PCFLs was confirmed by the chlorination mixtures of fluorene and 2-methylfluorene.

Several congeners were found for each compound groups studied and isomer patterns were similar in bleached pulp and biosludge. The approximated sum levels of di- and trichloro isomers of PCFLs, C₁-PCFLs and C₂-PCFLs in the biosludge were about 2, 5 and 4 ng/g dry weight (dw), respectively. The levels of the corresponding compounds in the softwood pulp were 0.5, 0.8 and 0.2 ng/g dw, respectively. Of the studied compounds, only C₁-diCFLs (0.01 ng/g dw) were detected in the hardwood pulp. In the effluent, PCFLs were non-detectable, but traces of C₁-diCFLs (0.5 ng/L) and C₂-pentaCFLs (0.06 ng/L) were found. These were observed mainly as dissolved in the filtrate and not as particle-bound.     

Polychlorinated dibenzo-p-dioxins and dibenzofurans in paper making from a pulp mill in China

An extensive investigation on the input, formation and fate of PCDD/Fs in a pulp mill using reeds as raw materials in China was carried out. The main PCDD/Fs input in the production process came from reeds, which may be contaminated by PCDD/Fs from sodium pentachlorophenate to control snailborne schistosomiasis. High levels of I-TEQ in the products were observed.     

Metal ion removal from water by sorption on paper mill sludge

Chromatographic columns packed with paper mill sludge are employed for metal ion recovery from water. The breakthrough curves show that cadmium, copper, lead and silver are removed from acid solutions (pH 2, 4); the affinity series is Pb(II)>Cu(II)>Ag(I)>Cd(II). Both the amount of metal retained and the metal-matrix interaction are pH dependent; the sorptive capacity increases with increasing pH. When the metals are present together at the same initial concentrations a competition among the different ions occurs although the affinity order remains unchanged. In metal recovery from the paper mill sludge column, the total amount of the cadmium and copper is displaced by HCl 1.0 M, 65% of the lead by HCl 0.1 M and 75% of the silver by HNO(3) 0.1 M. More than 95% of copper and lead and less than 20% of cadmium were recovered with HCl 0.1 M when the metals were present at the same time.     

Spectroscopic changes on fulvic acids from a kraft pulp mill effluent caused by sun irradiation

Large volumes of wastewater with a high organic load are generated by the pulp and paper industry that negatively affect the quality of receiving waters. The main waste products in the pulp mill effluents are lignin derived macromolecular compounds, which are similar to natural humic substances and very resistant to wastewater treatments. Fulvic acids (FA) represent the higher percentage of these humic substances and it was observed that solar irradiation modify their properties. Several analytic tools, namely, UV–Visible, molecular fluorescence and FTIR spectroscopies, were used to assess the effect of solar exposition on fulvic acids from a kraft pulp mill effluent. It may be concluded that sun irradiation may alter to a high extent the physicochemical properties of macromolecular organic matter, namely fulvic acids, released by kraft pulp mill effluents. After solar exposition, the aromaticity decreases, the aliphatic structures become more oxygenated, and the fulvic acids from the pulp mill effluent remaining in solution are more similar to aquatic fulvic acids from non polluted sites.     

Spectroscopic changes on fulvic acids from a kraft pulp mill effluent caused by sun irradiation

Large volumes of wastewater with a high organic load are generated by the pulp and paper industry that negatively affect the quality of receiving waters. The main waste products in the pulp mill effluents are lignin derived macromolecular compounds, which are similar to natural humic substances and very resistant to wastewater treatments. Fulvic acids (FA) represent the higher percentage of these humic substances and it was observed that solar irradiation modify their properties. Several analytic tools, namely, UV–Visible, molecular fluorescence and FTIR spectroscopies, were used to assess the effect of solar exposition on fulvic acids from a kraft pulp mill effluent. It may be concluded that sun irradiation may alter to a high extent the physicochemical properties of macromolecular organic matter, namely fulvic acids, released by kraft pulp mill effluents. After solar exposition, the aromaticity decreases, the aliphatic structures become more oxygenated, and the fulvic acids from the pulp mill effluent remaining in solution are more similar to aquatic fulvic acids from non polluted sites.     

Enhanced biological phosphorus removal and recovery

Activated sludge systems designed for enhanced nutrient removal are based on the principle of altering anaerobic and aerobic conditions for growth of microorganisms with a high capacity of phosphorus accumulation. Most often, filamentous bacteria constitute a component of the activated sludge microflora. The filamentous microorganisms are responsible for foam formation and activated sludge bulking. The results obtained confirm unanimously that the filamentous bacteria have the ability of phosphorus uptake and accumulation as polyphosphates. Hydrodynamic disintegration of the foam microorganisms results in the transfer of phosphorus and metal cations and ammonium-nitrogen into the liquid phase. It was demonstrated that the disintegration of foam permits the removal of a portion of the nutrients in the form of struvite.     

Emissions of sulfur trioxide from coal-fired power plants

Emissions of sulfur trioxide (SO3) are a key component of plume opacity and acid deposition. Consequently, these emissions need to be low enough to not cause opacity violations and acid deposition. Generally, a small fraction of sulfur (S) in coal is converted to SO3 in coal-fired combustion devices such as electric utility boilers. The emissions of SO3 from such a boiler depend on coal S content, combustion conditions, flue gas characteristics, and air pollution devices being used. It is well known that the catalyst used in the selective catalytic reduction (SCR) technology for nitrogen oxides control oxidizes a small fraction of sulfur dioxide in the flue gas to SO3. The extent of this oxidation depends on the catalyst formulation and SCR operating conditions. Gas-phase SO3 and sulfuric acid, on being quenched in plant equipment (e.g., air preheater and wet scrubber), result in fine acidic mist, which can cause increased plume opacity and undesirable emissions. Recently, such effects have been observed at plants firing high-S coal and equipped with SCR systems and wet scrubbers. This paper investigates the factors that affect acidic mist production in coal-fired electric utility boilers and discusses approaches for mitigating emission of this mist.     

Mercury emission from coal-fired power plants in Poland

The paper reviews the current state of knowledge regarding sources of mercury emission in Poland. Due to the large quantities of coal burned at present, as well as taking into account existing reserves, coal remains the main energy source of energy in Poland. The data on coal consumption in Poland in the past, at present and in the future are discussed in the paper. Information on the content of mercury in Polish coals is presented.Coal combustion processes for electricity and heat production are the main source of anthropogenic mercury emission in Poland. It is expected that the current emissions will decrease in the future due to implementation of efficient control measures. These measures for emission reduction are described in the paper. Results of estimated mercury emission from coal-fired power station situated in the Upper Silesia Region, Poland are investigated. A relationship between mercury emission to the air and the mercury content in the consumed coal in power station equipped with the electrostatic precipitators (ESPs) is discussed.     

制浆造纸废水生化出水的混凝处理研究

研究了硫酸铝和三氯化铁对制浆造纸废水生化出水的处理效果.研究发现,不调节原水pH值,硫酸铝投加量为600 mg/L或三氯化铁投加量为300mg/L时,混凝后废水的COD＜150 mg/L,色度＜50倍,出水均符合现阶段排放标准.混凝剂比较发现,在最佳反应条件下,2种混凝剂的处理效果相当,但硫酸铝混凝的成本低于三氯化铁....     

Effect of limited aeration on the anaerobic treatment of evaporator condensate from a sulfite pulp mill

Serious inhibition was found in the regular up-flow anaerobic sludge blanket (UASB) reactor in treating the evaporator condensate from a sulfite pulp mill, which contained high strength sulfur compounds. After applying the direct limited aeration in the UASB, the inhibition was alleviated gradually and the activity of the microorganisms was recovered. The COD removal rate increased from 40% to 80% at the organic loading rate of 8kgCODm(-3)d(-1) and a hydraulic retention time of 12h. Limited aeration caused no oxygen inhibition to the anaerobic microorganisms but instigated sulfide oxidization and H(2)S removal, which was beneficial to the methanogens. The experiment confirmed the feasibility of applying limited aeration in the anaerobic reactor to alleviate the sulfide inhibition. It also proved that the anaerobic system was actually aerotolerant. SEM observation showed that the predominant microorganisms partly changed from rod-shaped methanogens to cocci after the UASB reactor was aerated.     

Changes in character of organics in the receiving environment of effluent from a sulphite pulp mill

Purpose

The characteristics of organics in sulphite pulp mill effluent and in the receiving environment of effluent discharge were investigated to assess the basis for the persistence or attenuation of colour.

Methods

Characterization of organics was conducted through determination of SUVA, specific colour, and molecular weight distribution of organics using high performance size exclusion chromatography and by solid-state ¹³?C cross polarization (CP) NMR. The characteristics of organics from mill wastewater before and after secondary aerobic treatment, followed by lime treatment and from the receiving environment, an enclosed brackish lake were compared. Changes in the character of organics in lake water over a period of 14?years were studied in the context of changes in mill processing and climate impacts.

Results

High colour in mill effluent and in receiving waters correlated with high SUVA and specific colour levels, high molecular weight range and aromatic content. Conversely, lake waters with low colour had UV absorbing compounds of much lower molecular weight range and low relative abundance of aromatic compounds. Attenuation of colour and changes in the character of organics in the receiving environment coincided with increased concentrations of metal cations.

Conclusions

These increased concentrations appear to be due to the effects of climate change, lake management and their presence in mill effluent, with subsequent discharge to the lake. Attenuation of colour was found to be predominantly through removal of high molecular weight aromatic compounds where the removal processes could be through adsorption and co-precipitation with divalent metals, as well as through dilution processes.     

Effects of solar radiation on the fluorescence properties and molecular weight of fulvic acids from pulp mill effluents

The pulp and paper industry generates large volume of wastewater that adversely affects water resources. Lignin derived macromolecular compounds, similar to natural humic substances, are the main waste products in the pulp mill effluents. The UV-Vis and fluorescence spectroscopies were used to assess the effect of solar exposition on fulvic acids from a kraft pulp mill effluent. Solar irradiation of the solutions of these fulvic acids caused solution acidification and decay both in the UV-Vis absorbance and in the fluorescence. This decay was not the same for the whole spectra but pointed to the selective photodegradation of lignin typical structures. Furthermore, by sequential ultrafiltration it was found that during irradiation, the high-molecular weight fractions were destroyed and low-molecular-weight constituents, potentially more able to penetrate the cell membranes of living organisms were formed. Photodegradation of macromolecular organic matter from a kraft pulp mill effluent may be a key process occurring in natural waters that modifies the physicochemical properties of such effluents.     

Composition of sulphurous exhaust gases from sulphate and semi-alkaline pulping (SAP) processes of a pulp mill

Twenty-three volatile S compounds were identified from the exhaust gases of sulphate and semialkaline pulping processes of a pulp mill.     

二氧化钛滤柱对高砷污酸废水的吸附去除

冶炼废水中高浓度砷的去除及回收是环境领域面临的一大挑战。提出利用颗粒TiO2填充滤柱对酸性废水中的高浓度砷进行连续在线吸附去除。经过3个连续串联的TiO2滤柱,原水中高达2.5 g·L-1的三价砷可降至国家工业废水排放标准以下（-1）。空床接触时间（EBCT）实验结果表明,当EBCT=20 min时滤柱中TiO2可达到最大利用率。使用后的TiO2颗粒可用H2SO4和NaOH进行反洗再生。X射线衍射分析结果表明,经过再生后颗粒TiO2的晶型并未发生变化,能够实现对砷的再吸附。基于同步辐射技术的微束X射线荧光（μ-XRF）分析结果表明,反洗后少量固体残渣中有多种重金属共存。砷的K边微束X射线近边吸收结构（μ-XANES）表明固体残渣中存在五价砷,说明反洗过程中三价砷部分氧化。固体残渣可以通过化学提纯的方式实现砷及多种共存重金属的回收。再生废液可与原酸性废水混合调pH至中性后重新进入滤柱进行吸附去除。提出的利用颗粒TiO2处理酸性冶炼废水的新方法可有效去除废水中的高浓度三价砷,吸附剂可重复利用,同时可以实现砷及其他重金属的回收,整个工艺流程几乎不产生废渣,对环境友好的同时可产生经济效益。