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Marine regulations aim to reduce sulfur and nitrogen exhaust emissions from maritime shipping. Here, two compliance pathways for reducing sulfur dioxide emissions, fuel sulfur content reduction and exhaust wet scrubbing, are studied for their effects on physicochemical properties and cloud forming abilities of engine exhaust particles. A test‐bed diesel engine was utilized to study fresh exhaust emissions from combustion of non‐compliant, high sulfur content fuel with (WS) and without (HiS) the usage of a wet scrubber as well as a regulatory compliant, low sulfur content fuel (LoS). Particle number emissions are decreased by ≈99% when switching to LoS due to absence of 20–30 nm sulfate rich particles. While number emissions for WS are also decreased, a shift in the sulfate mode toward larger sizes was found to increase particle mass emission factors by at least 31%. Changes in the mixing state induced by the compliance measures are reflected in the hygroscopicity of the exhaust particles. Fuel sulfur reduction decreased cloud condensation nuclei emissions by at least 97% due to emissions of primarily hydrophobic soot particles. Wet scrubbing increased those emissions, mainly driven by changes in particle size distributions. Our results indicate that both compliance alternatives have no obvious impact on the ice forming abilities of 200 nm exhaust particles. These detailed results are relevant for atmospheric processes and might be useful input parameters for cloud‐resolving models to investigate ship aerosol‐cloud interactions and to quantify the impact of shipping on radiative budgets from local to global scales. Plain Language Summary: We investigate how two pathways to comply with international regulations, aiming to reduce emissions of atmospheric pollutants from ships, alter properties of exhaust particles. Both investigated compliance measures (i.e., combustion of cleaner, low sulfur content fuels and aftertreatment of exhaust from a high sulfur content fuel via wet scrubbing) have substantial impacts on the chemical and physical properties of these particles. We find that, while both alternatives reduce the total number of emitted particles substantially, the effect on emissions of cloud forming particles is path dependent. While fuel sulfur content reduction decreased the number of cloud forming particles by about 97%, wet scrubbing led to a strong increase in emissions, suggesting that the measures can have substantial and opposing impacts on local cloud formation and evolution. Key Points: Low sulfur content fuels can reduce emissions of ultrafine particulate matter significantlyExhaust wet scrubbing can lead to shifts in particle size distributions and reduce soot emissionsUsage of low sulfur content fuels or exhaust wet scrubbing have opposing effects on CCN activity of ship exhaust particles [ABSTRACT FROM AUTHOR]

Small scale gasification combined heat and power (CHP) systems offer an alternative to diesel fuelled generators for power generation in remote communities and industrial sites. Tar and particulates in the producer‐gas can damage the internal combustion engine generator and increase operation and maintenance costs. In this work, we present a novel trickle‐bed scrubber using filtered waste cooking oil as a cost effective and easy‐to‐operate gas clean‐up method for a small CHP system. The performance of the trickle‐bed scrubber was compared against a packed‐bed filter utilizing woodchips in a 20 kWth downdraft gasifier. Used‐cooking oil was selected as the solvent and woodchips as the bed‐material as these are readily available, inexpensive, and can be recycled in the gasifier as fuel. A woodchip packed‐bed filter reduced the tar and particulate matter (PM) in the producer gas from gasification of spruce chips (11% moisture) from 1.6 to 1.4 g/Nm3 and from 0.16 to 0.087 g/Nm3 respectively. The trickle‐bed scrubber was able to reduce the tar and PM in the producer gas from gasification of pinewood (8% moisture) from 1.38 to 0.28 g/Nm3, and 0.209 to 0.082 g/Nm3, respectively. Tar and PM removal efficiency improved by 60% and 29% respectively. Components such as benzene, toluene, naphthalene, and biphenylene were the major tar components. After passing the trickle‐bed, most tar was removed, with a preference for removal of multi‐ringed aromatics and gravimetric tars. Parameters such as the tar and particulate concentration, feedstock moisture content, and feedstock source affect the performance of the gas clean‐up system. [ABSTRACT FROM AUTHOR]

In contrast to conventional dry separators, new types of wet scrubbers with innovative nozzle geometries are capable of separating submicron particles with comparatively low pressure drop. As those geometries can easily be adapted using 3D‐printing manufacturing, an applied geometry optimization can lead to a fast and cost‐efficient product development cycle. In this study, the lattice Boltzmann method is used to optimize the pressure drop associated with a novel nozzle design. Simulated pressure drop data are validated with experimentally determined ones. By replacing originally installed ellipsoid‐shaped bluff bodies with foil‐shaped structures according to the 4‐digit NACA‐series, an optimization approach regarding the resulting pressure drop is described. [ABSTRACT FROM AUTHOR]

Small‐scale biomass boilers contribute to the emission of particulate matter (PM) to the environment. In this study, the performance of a wet‐scrubber purification system for flue gas was experimentally investigated. The experimental setup consisted of a boiler, a wet scrubber, a generator, and heat exchangers. The results showed an average PM collection efficiency of ca. 42 % for a PM size range of 0.08–10 µm over a testing period of five months. Furthermore, the results showed an improvement in the heat recovery of about 18 %. Focusing only on the heat losses through exhaust flue gases, the losses were shown to have decreased by 72 %. During the total testing period of 8.5 months, no decrease could be noticed in the absorption solution ability. [ABSTRACT FROM AUTHOR]

This paper describes and discusses experimental results on the absorption of sulphur dioxide in electrified water sprays, either when the polluted gas is treated as is or when the gas is exposed to a corona source to ionize the sulphur dioxide. The experiments revealed that an electrified spray with a charge‐to‐mass ratio of 50 μC · kg−1 enabled the absorption rate of droplets to double, regardless of their polarities. Corona charging gave rise to an increase in the SO2 depletion rate over the scrubber wall, while negligible effects appeared on the actual droplets absorption rate. These findings suggested that faster absorption rates mostly, though not uniquely, depend on the modifications on the morphological and interfacial properties of the sprayed droplets induced by the free electric charge imposed on their surface. Conversely, the absorption rates were negligibly affected by the electrical interactions between droplets (either charged or uncharged) and the sulphur dioxide ions/radicals originating from the corona source. [ABSTRACT FROM AUTHOR]

Abstract: BACKGROUND: The mass transfer of volatile organic compounds (VOCs) from waste gas streams to liquid in scrubbers is determined by the overall volumetric mass transfer coefficient (Kga), which is dependent on the air‐to‐water partition coefficient (KAW, dimensionless). The application of additives in the water phase can alter this KAW to lower values thus increasing the Kga. Previous research provided partitioning data of new scrubber liquids and this study will link the partitioning data with mass transfer characteristics in a pilot‐scale scrubber. RESULTS: The Kga was experimentally determined using a VOC pulse addition response (PAR) method in a pilot‐scale scrubber with randomised or structured packing (1.6 m height, diameter 0.1 m). VOCs were injected at the inlet of the scrubber. SIFT‐MS was used for the online measurement of the VOC concentration. An advection–absorption model was used to calculate the Kga values for a set of VOCs and different scrubber liquid properties. Scrubber liquids and VOCs were applied to evaluate the Kga values in a KAW range from 2.6 × 10‐3 to 4.0 × 10, a gas velocity between 0.34 and 1.17 m s‐1 and liquid flow of 0.4 m3 h‐1. The obtained Kga ranged from 0 to 2.27 s‐1. CONCLUSION: A relationship between the Kga, gas velocity and KAW was established. Based on this mathematical model, the economical/technical suitability of applying an additive to the scrubbing liquid of industrial installations can be evaluated. β‐cyclodextrin was applied as additive in the scrubber and Kga values were significantly higher than with pure water. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Abstract: BACKGROUND: Air scrubbers are commonly used as treatment techniques for industrial waste gases containing volatile organic compounds (VOCs). Mass transfer of hydrophobic compounds to liquid can be increased using water soluble additives in the scrubbing liquid or applying water‐miscible or immiscible solvents. The design of air scrubbers requires reliable partition data, which are limited in the literature. This manuscript provides partitioning data of new scrubber liquids and subsequent research will link the partitioning data with mass transfer characteristics in a pilot‐scale scrubber. RESULTS: The DynAb method was applied for the first time to a broad set of gas–liquid systems to study the partitioning behaviour of volatile organic sulphides and aldehydes. Cyclodextrins (CD) were chosen as water soluble additives. Silicone oil (SO) and isopropylmyristate (IPM) were used as water immiscible solvents, whereas dipropylene glycol methyl ether was applied as a water‐miscible solvent. The inclusion of VOCs into the CD structure is very compound specific. Binding constants were calculated to quantify the CD‐VOC affinity and the partitioning behaviour of the VOCs with oils and solvents was quantified. The air‐to‐water partition coefficient of hexanal could be reduced more than 50 times with a concentration of 72 g L‐1 α‐CD. IPM (100% v/v) could reduce the air‐to‐IPM partitioning coefficient by a factor of 120 for dimethyl disulphide. CONCLUSION: The determined partition coefficients can be used for suitability evaluation for the design and modelling of air treatment systems. A broad range of evaluated gas–liquid systems provides quantitative knowledge about VOC behaviour. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The gas, liquid, and dust particle behavior inside a centrifugal wet scrubber was simulated and a submodel for predicting its collection efficiency was developed that also takes in account the reduction in collection efficiency due to droplet carryover. Centrifugal wet scrubbers are used in many industries and deliver a high scrubbing efficiency at relatively low capital and operational costs. However, they often experience problems such as droplet carryover at high gas flows and reduced collection efficiency at low gas flows. An improved understanding of flow processes inside the scrubbers is needed to develop a better scrubber design. An experimental test facility was setup for this purpose which also served to validate the CFD modeling results. Ideal operating parameters for maximum scrubbing efficiency and minimum droplet carryover were identified. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1001–1012, 2018 [ABSTRACT FROM AUTHOR]

The most common technology for postcombustion of CO2 capture is the amine solvent scrubber. The energy consumption for capturing CO2 from flue gases using amine solvent technology is 15-30% of the power plant electricity production. Hence, there is a need to develop more efficient methods of removing CO2. A circulating fluidized bed using sodium or potassium carbonates is potentially such a process, as their high decomposition pressures allow regeneration at low temperatures using waste heat rather than steam from the power plant. But equilibrium data for the sorbents require the use of several cooled stages to achieve high CO2 conversions. Here, a method of computing such a number of stages for a given CO2 conversion was developed using multiphase computational fluid dynamics. It was found that it required six equilibrium stages to remove 96% of CO2 with the initial mole fraction of 0.15 in a sorption riser. © 2017 American Institute of Chemical Engineers AIChE J, 63: 5267-5279, 2017 [ABSTRACT FROM AUTHOR]

Chemical air scrubbers reduce the concentration of water-soluble components such as ammonia from the outgoing ventilation air through absorption in water, followed by chemical conversions and removal of the end products. A mechanistic model for a counter current air scrubber was set up. Mass balances for ammonia, hydrogen sulfide, nitrous oxide, and methane were implemented, as well as the water mass balance and heat balances. The model was validated against experimental data from a conventional fattening pig housing facility. The effect of influent characteristics, design parameters, and control handles on the removal efficiency, the temperature profile, and the water evaporation rate were investigated through simulation. The model was able to describe the behavior of a countercurrent chemical air scrubber. [ABSTRACT FROM AUTHOR]

We describe a mobile CO2 scrubbing platform that offers a greatly accelerated biomimetic sequestration based on a self-propelled carbonic anhydrase (CA) functionalized micromotor. The CO2 hydration capability of CA is coupled with the rapid movement of catalytic micromotors, and along with the corresponding fluid dynamics, results in a highly efficient mobile CO2 scrubbing microsystem. The continuous movement of CA and enhanced mass transport of the CO2 substrate lead to significant improvements in the sequestration efficiency and speed over stationary immobilized or free CA platforms. This system is a promising approach to rapid and enhanced CO2 sequestration platforms for addressing growing concerns over the buildup of greenhouse gas. [ABSTRACT FROM AUTHOR]

Hyperlink extraction technology, by virtue of its remarkable advantage of decreasing the use of chemicals in multi-component separation, has been extensively employed in rare earth separation industry in China. In hyperlink processes, non-barren extracting solvent and scrubbing agent solution which contain the component(s) involved in starting feed are employed in order to save both alkali for saponification and acid for scrubbing. Minimum amount of extracting solvent (denoted as Smin) and that of scrubbing agent solution (denoted as Wmin) are important parameters to determine the consumption amounts of alkali and acid for a given countercurrent extraction separation. This article therefore discusses the influence of using non-barren extracting solvent and scrubbing agent solution on Smin and Wmin of an (A1A2···A t−1)/(A2A3···A t) separation. The equations for Smin and Wmin are derived, and the variation of the composition of final raffinate as well as that of final extract are determined, which will provide a valuable guidance for the design of hyperlink extraction processes of multi-component separation, such as rare earths separation. [ABSTRACT FROM AUTHOR]

This research study was undertaken to enhance the efficiency and economy of carbon scrubbers in controlling odors and volatile organic compounds (VOCs) at the wastewater collection and treatment facilities of the Bureau of Sanitation, City of Los Angeles. The butane activity and hydrogen sulfide breakthrough capacity of activated carbon were assessed. Air streams were measured for odorous gases and VOCs and removal efficiency (RE) determined. Carbon towers showed average to excellent removal of odorous compounds, VOCs, and siloxanes; whereas, wet scrubbers demonstrated good removal of odorous compounds but low to negative removal of VOCs. It was observed that the relative humidity and empty bed contact time are one of the most important operating parameters of carbon towers impacting the pollutant RE. Regular monitoring of activated carbon and VOCs has resulted in useful information on carbon change-out frequency, packing recommendations, and means to improve performance of carbon towers. [ABSTRACT FROM AUTHOR]

Modularization has been identified as one of the research fields of the '50 % idea'︁. A development methodology for modules must consider both the economies of scale for investment costs and costs of operation and maintenance. In this paper, the impact of an absorber module, which is offered as discretized diameter scaling, on the total process is investigated at the example of the CO2 separation from biogas. The simulation shows the effect of this approach to the stripper diameter and the energy demand of the process. The calculations form the basis for applying cost models. [ABSTRACT FROM AUTHOR]

To develop a system supporting rapid growth of juvenile freshwater mussels, a recirculating aquaculture system was designed and built at the Laboratory for Conservation Aquaculture and Aquatic Ecology, Virginia Polytechnic Institute and State University. The system included a rectangular trough tank, a sump (biofilter), a pump, a microalgae drip feeder, and an air delivery system. An algal turf scrubber (ATS) was evaluated for its potential to maintain and improve water quality within the system. Growth and survival rates of juvenile rainbow musselsVillosa irisafter 90 d were compared between system units with and without ATSs. Flow rate through the culture units was approximately 23.3 L/min. Results showed no statistically significant differences between the growth and survival rates of juvenile mussels reared in systems with ATSs and those reared in systems without ATSs. Ammonia and nitrite levels were low and did not differ among treatments. However, systems with ATSs exhibited significantly lower levels of nitrate and phosphate than systems without ATSs. Our results show that freshwater mussel culture systems can be scaled up to increase production and that the use of ATSs may help to maintain water quality in recirculating aquaculture systems during long-term culture of freshwater mussels. Received February 4, 2013; accepted July 12, 2013 [ABSTRACT FROM PUBLISHER]

Sulfur dioxide (SO2) is one of the pollutant gases that result from energy conversion by coal and oil combustion. Limestone slurries are widely utilized in wet flue gas desulfurization (WFGD) processes. The evaluation of the reagent's reactivity is fundamental for process design and plant operation. The comparison of different limestone and dolomite rocks through dissolution experiments was realized by applying a model for second-order kinetics. And a total of 12 different samples were tested, at three different size fractions. A simulation model was developed to identify each sample's impact on sizing the dissolution tank of a WFGD scrubber. A second-order model was applied within the scrubber's dissolution tank range of operation at pH values between 4 and 5. The regression coefficients for the second-order model were higher than 0.98 in all cases. The dissolution tank volume estimation was done based on the reagent's overall chemical reaction constant in dissolution experiments. The limestone rocks, where the prevailing mineral was calcite (CaCO3), demonstrated higher chemical reactivity yielding smaller dissolution tank volumes than the dolomite rocks, where the prevailing mineral was dolomite (CaMg(CO3)2). The CaO and MgO content of a sample can be used to predict the dissolution rate; nevertheless more factors influence the rate and the tank sizing. The knowledge of the sample's composition and its reactivity is necessary for the design of a desulfurization scrubber; the reagent used is determinant for the economy and optimal operation of such scrubbers. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 663-672, 2013 [ABSTRACT FROM AUTHOR]

The goal of this study is to evaluate the performance of a fixed valve tray column designed to remove fly-ash particles. A series of experiments were carried out at room temperature to demonstrate the collection efficiency of a fixed valve tray column at different gas and liquid superficial velocities. The fly-ash particles removal characteristics of the fixed valve tray column were evaluated by measuring variations of concentration and size distribution of particles in the outlet. The mechanism of particle removal in this turbulent dispersion system was theoretically analyzed on the basis of diffusion, interception, sedimentation and impaction, and a model was proposed to predict the collection efficiency. The results show that the simulation results agree well with the experimental data. In contrast to most of the conventional models, the present model is capable of evaluating the effects of bubble hydrodynamics, system property, and operation conditions on the collection efficiency. The model is expected to guide effectively the design and operation of valve tray washing columns, which is widely applied nowadays. © 2012 American Institute of Chemical Engineers AIChE J, 59: 2168-2178, 2013 [ABSTRACT FROM AUTHOR]

An unsteady model of SO2 absorption in fall-down spherical seawater droplets is presented, focused on marine diesel engine exhaust gas scrubbing. The model evaluates the amount of sulfur dioxide absorbed by a single droplet, with given initial velocity, diameter, and alkalinity, falling counter-flow with respect to the exhaust gas stream. Kinematics of the droplet, heat exchange, and evaporation has been considered, taking into account internal circulation. Neutralization of absorbed sulfur species in the droplet has been modeled with a global and fast reaction mechanism. Transport equations for species inside the droplet have been solved on a nonuniform computational grid, which is regenerated at every time step to account for droplet diameter reduction. The single-droplet model has been incorporated in a simple scrubber plug-flow model, to evaluate the desulfurization efficiency and the seawater supply rate under realistic marine engine exhaust gas desulfurization conditions. The influence of flue gas inlet temperature, flue gas velocity, initial droplet size, and velocity on the scrubbing process were investigated. Results of this model are valuable for judging the feasibility and operating costs of this SO2 scrubbing technique compared with alternative methods. © 2011 American Institute of Chemical Engineers Environ Prog, 2011 [ABSTRACT FROM AUTHOR]

A pilot-scale study of sodium sulfide (Na2S) aqueous solutions for NO2 absorption was conducted to obtain field data for process design and system operations. Considered parameters include Na2S concentrations in the scrubbing solutions, gas mass flow rate, liquid mass flow rate, liquid/gas ratio (L/G), pH, and gas residence time. The effects of these parameters on NO2 absorption in a packed tower were investigated thoroughly. The height of transfer unit of the system was deducted as a function of the tested parameters that can be used for designing a NOx scrubbing system. The absorption of NO2 is not sensitive to the inlet NO2 concentration. However, as expected, the NO2 absorption increases with the increase of L/G ratio. An L/G greater than 2.5 is essential to a practical NO2 scrubbing application. The pilot test suggested that the scrubbing solution is with Na2S concentration greater than 0.0015 M at pH 9. The solution effectively removed more than 90% of the incoming NO2 in the five-foot height packed bed scrubber. The study also indicates that a gas residence time of 4.5 s is essential to achieve more than 80% NO2 absorption. © 2011 American Institute of Chemical Engineers Environ Prog, 2011. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Chemical Engineering is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article presents a study on sulfur dioxide (SO2) removal using wastewater from a leather factory's liming and unhairing unit using a scrubber in Elazig, Turkey. The five inlet flue SO2 concentrations used for experimentation were at 1000 to 5000 pounds per minute (ppm). Results show 96 to 99% maximum sulfur removal efficiency and that inlet SO2 concentration has influenced the process. It notes that wastewater is effective in SO2 removal.

The article reports on the creation of a flexible tar removal process by the Energy research Centre (ECN) in the Netherlands that uses an oil-based gas washing process (OLGA). The process also removes dust and other contaminants such as thiophenes and dioxins. Because OLGA does not remove valuable hydrocarbons including methane (CH4), acetylene (C2H2), and ethylene (C2H4), it plays a crucial role in the high-efficient production of Substitute Natural Gas (SNG). In-depth discussions regarding tars in product gas, their removal, and the principles behind OLGA technology are presented. A comparison between OLGA and alternative technologies for tar removal, as well as research and development (R&D) at ECN, are also discussed.

The article examines the potential for a particulate-laden sulfur dioxide scrubbing system within the performance of tapered bubble columns generating fractional gas. Quiescent batch studies found that various particle concentrations improved the removal efficiency of sulfur dioxide by 14 – 27 percent. These figures were elucidated via adsorptive mass transport. Subsequent experiments evaluated the performance of this system under continuous mode for scrubbing using water and dilute sodium hydroxide.

Biomass from a prototype reactor was used to investigate the kinetics of chemoheterotrophic reduction of solutions of ferric ethylenediaminetetraacetic acid (EDTA) and solutions containing the nitrosyl adduct of ferrous EDTA using ethanol as the primary electron donor and carbon source. A series of batch experiments were conducted using biomass extracted from the scrubber solution treatment and regeneration stage of a prototype iron EDTA-based unit process for the absorption of nitric oxide with subsequent biological treatment. Using a linear-sweep voltammetric method for analysis of the ferric EDTA concentration, iron-reducing bacteria were found to behave according to the Monod kinetic model, at initial concentrations up to 2.16 g chemical oxygen demand (COD) as ethanol per liter, with a half-velocity constant of 0.532 g COD as ethanol/L and a maximum specific utilization rate of 0.127 mol/L of ferric ethylenediamine-tetraacetic acid [Fe(III)EDTA]*(g volatile suspended solids [VSS]/L)d-1. Based on batch analyses, biomass yield and endogenous decay values of iron-reducing bacteria were estimated to be 0.055 g VSS/g COD and 0.017 L/d, respectively. An average of 1.64 times the theoretical (stoichiometric) demand of ethanol was used to complete reduction reactions. Kinetics of the reduction of the nitrosyl adduct of ferrous EDTA are summarized by the following kinetic constants: half-velocity constant (KS) of 0.39 g COD/L, maximum specific utilization rate (k) of 0.2 mol/L [NO · Fe(II)EDTA2-](g VSS/L)d-1, and inhibition constant (KI) of 0.33 g COD/L, as applied to the modified Monod kinetic expression described herein. Based on batch analyses, the biomass yield of nitrosyl-adduct-reducing bacteria was estimated to be 0.259 g VSS/g COD, endogenous decay was experimentally determined to be 0.0569 L/d, and an average of 1.26 times the stoichiometric demand of ethanol was used to complete reduction reactions. [ABSTRACT FROM AUTHOR]

Discusses the operation of a novel hybrid scrubber for particulate control efficiency. Design of the experimental setup; Effect of inlet fly-ash loading and gas flow rate; Effect of liquid to gas flow rate ratio.

Copyright of Canadian Journal of Chemical Engineering is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Investigates a basic purge model that is applicable over a wide range of vessel purge or gas sweep operations for batch and continuous chemical processes. Significance of the model in accessing the environmental impact for chemical manufacturing processes; Modeling guidelines for the purge or gas sweep operations; Solvent mixtures and components used in estimating the saturation level for each volatile component.

Full-scale trial: NO SB x sb reduction in a hazardous waste treatment plant via ozone injection and caustic wet scrubbing. The NO SB x sb reduction effectivity can be enhanced by caustic scrubbing. The tested process is a NO SB x sb reduction technique that can be implemented easily in existing plants, provided a wet scrubber exists. [Extracted from the article]

The article focuses on the utilization of Purafil ESD for the elimination of wastewater odors in Barcelona, Spain. It is stated that Besos Wastewater Treatment Plant (WWTP) in northeastern Barcelona is a revolutionary solution for its more than 2 million inhabitants. Accordingly, when the population and the tourist traffic in Barcelona have grown to overwhelming proportions, odors from the city's increasing amounts of wastewater have also grown. Meanwhile, the Ministry of Environment decided to enlarge and update the Besos WWTP in an effort to eliminate the odors, while enhancing the surroundings visually. Meanwhile, a division of Purafil ESD manufactures a broad range of dry-chemical media and scrubbers that remove odors and prevent corrosion of electronics.

A correction to the article "Particulate-Laden-SO2 Scrubbing in a Tapered Bubble Column" that was published in the previous issue is presented.

The author discusses the use of new technologies in extraction of coal. Topics discussed include use of directional drilling and improved oxidation control to made underground coal gasification processes easy; information on the technologies to reduce harmful emissions including coal washing to remove unwanted minerals and wet scrubbers to limit sulphur dioxide, nitrogen oxides emissions and; use of Underground coal gasification (UGC) for the in situ conversion of coal in coal seams.

Presents a letter to the editor about chemical scrubber.