Effect of Diffusiophoresis and Thermophoresis on the Overall Particle Collection Efficiency of Spray Droplet Scrubbers

The overall particle collection efficiencies of spray scrubbers using monodisperse droplets of 100,500, and 1000 microns diameter were calculated for the cases of evaporating and condensing droplets. The properties of the gas at the inlet to the spray scrubber were maintained constant at 150°F, 100% relative humidity, and 1 atmosphere pressure. At the liquid entrance to the spray scrubber, the water droplet temperature was 50° F for the condensing case and 180° F for the evaporating case. The liquid to gas flow rate ratio for all the calculations was held constant at 4 gal/1000 acf. The gas velocity in the co-current spray tower was 1 ft/sec in the downwind direction. The calculation results show that for the particles in the 0.01 to 10 Mm diameter range, the overall spray scrubber particle collection efficiency is greater with the cooler 50°F water (condensing case) than with the warmer 180°F water (evaporating case). The effect of diffusiophoresis and thermophoresis is noticeable for all the water droplet sizes considered, but is more significant for the larger water droplets. This greater effect for the larger water droplets compared to the smaller droplets is due to the longer existence of the temperature and water vapor concentration gradients between the water droplets and the surrounding gas.     

Product Guide/1982

Abstract

An efficient venturi scrubber system making use of heterogeneous nucleation and condensational growth of particles was designed and tested to remove fine particles from the exhaust of a local scrubber where residual SiH₄ gas was abated and lots of fine SiO₂ particles were generated. In front of the venturi scrubber, normal-temperature fine-water mist mixes with high-temperature exhaust gas to cool it to the saturation temperature, allowing submicron particles to grow into micron sizes. The grown particles are then scrubbed efficiently in the venturi scrubber. Test results show that the present venturi scrubber system is effective for removing submicron particles. For SiO₂ particles greater than 0.1 μm, the removal efficiency is greater than 80–90%, depending on particle concentration. The corresponding pressure drop is relatively low. For example, the pressure drop of the venturi scrubber is ～15.4 ± 2.4 cm H₂O when the liquid-to-gas ratio is 1.50 L/m³. A theoretical calculation has been conducted to simulate particle growth process and the removal efficiency of the venturi scrubber. The theoretical results agree with the experimental data reasonably well when SiO₂ particle diameter is greater than 0.1 μm.     

Evaluating the performance of a turbulent wet scrubber for scrubbing particulate matter

A turbulent wet scrubber was designed and developed to scrub particulate matter (PM) at micrometer and submicrometer levels from the effluent gas stream of an industrial coal furnace. Experiments were conducted to estimate the particle removal efficiency of the turbulent scrubber with different gas flow rates and liquid heads above the nozzle. Particles larger than 1 µm were removed very efficiently, at nearly 100%, depending upon the flow rate, the concentration of the dust-laden air stream, and the water level in the reservoir. Particles smaller than 1 µm were also removed to a greater extent at higher gas flow rates and for greater liquid heads. Pressure-drop studies were also carried out to estimate the energy consumed by the scrubber for the entire range of particle sizes distributed in the carrier gas. A maximum pressure drop of 217 mm H₂O was observed for a liquid head of 36 cm and a gas flow rate of 7 m³/min. The number of transfer units (NTU) analysis for the efficiencies achieved by the turbulent scrubber over the range of particles also reveals that the contacting power achieved by the scrubber is better except for smaller particles. The turbulent scrubber is more competent for scrubbing particulate matter, in particular PM_2.5, than other higher energy or conventional scrubbers, and is comparable to other wet scrubbers of its kind for the amount of energy spent.

Implications: The evaluation of the turbulent scrubber is done to add a novel scrubber in the list of wet scrubbers for industrial applications, yet simple in design, easy to operate, with better compactness, and with high efficiencies at lower energy consumption. Hence the turbulent scrubber can be used to combat particulate from industrial gaseous effluents and also has a scope to absorb gaseous pollutants if the gases are soluble in the medium used for particles capture.     

Performance of Gas-Atomized Spray Scrubbers at High Pressure

A large number of pressurized coal gasification processes being developed propose to use venturi scrubbers for particulate removal at high pressures. Theoretical predictions based on venturi scrubber performance models indicate that particle collection efficiency will decrease severely in these high gas pressure applications.

An exploratory theoretical and experimental program was performed to study the effect of gas pressure on venturi scrubber performance. Experiments were done on a 0.47 m³/s (1000 acfm) pilot scale venturi scrubber. Particle collection performance was determined as a function of scrubber pressure drop for venturi scrubbers operating In the range of 1-10 atm total pressure. Experimental results confirmed that the particle collection efficiency of venturi scrubbers decreases for a given scrubber pressure drop as total gas pressure Is increased. To achieve the same particle collection efficiency, the pressure drop across a venturi scrubber operated at 10 atm Is about 10 times that of the same scrubber operated at 1 atm pressure.     

Effect of Water and Carbon Dioxide in Chemiluminescent Measurement of Oxides of Nitrogen

ABSTRACT

This paper reports results of studies using a biotrickling filter with blast-furnace slag packings (sizes = 2–4 cm and specific surface area = 120 m²/m³) for treatment of ethylether in air stream. Effects of volumetric loading, superficial gas velocity, empty bed gas retention time, recirculation liquid flow rate, and biofilm renewal on the ethylether removal efficiency and elimination capacity were tested. Results indicate that ethylether removal efficiencies of more than 95% were obtained with an empty bed retention time (EBRT) of 113 sec and loadings of lower than 70 g/m³/hr. At an EBRT of 57 sec, removal efficiencies of more than 90% could only be obtained with loadings of lower than 35 g/m³/hr. The maximum elimination capacities were 71 and 45 g/m³/hr for EBRT = 113 and 57 sec, respectively. The maximum ethylether elimination capacities were 71 and 96 g/m³/hr, respectively, before and after the renewal at EBRT = 113 sec. With an EBRT of 113 sec and a loading of lower than 38 g/m³/hr, the removal efficiency was nearly independent of the superficial liquid recirculation velocity in the range of 3.6 to 9.6 m³/m²/hr. From data regression, simplified mass-transfer limited, and reaction- and mass-transfer limited models correlating the contaminant concentration and the packing height were proposed and verified. The former model is applicable for cases of low influent contaminant concentrations or loadings, and the latter is applicable for cases of higher ones. Finally, CO₂ conversion efficiencies of approximately 90% for the influent ethylether were obtained. The value is comparable to data reported from other related studies.     

Performance of Copper Chloride-Impregnated Sorbents on Mercury Vapor Control in an Entrained-Flow Reactor System

Abstract

An entrained-flow system has been designed and constructed to simulate in-flight mercury (Hg) capture by sorbent injection in ducts of coal-fired utility plants. The test conditions of 1.2-sec residence time, 140 °C gas temperature, 6.7 m/sec (22 ft/sec) gas velocity, and 0–0.24 g/m³ (0–15 lbs of sorbent per 1 million actual cubic feet of flue gas [lb/MMacf]) sorbent injection rates were chosen to simulate conditions in the ducts. Four kinds of sorbents were used in this study. Darco Hg-LH served as a benchmark sorbent with which Hg control capability of other sorbents could be compared. Also, Darco-FGD was used as a representative raw activated carbon sorbent. Two different copper chloride-impregnated sorbents were developed in our laboratory and tested in the entrained-flow system to examine the possibility of using these sorbents at coal-fired power plants. The test results showed that one of the copper chloride sorbents has remarkable elemental mercury (Hg⁰) oxidation capability, and the other sorbent demonstrated a better performance in Hg removal than Darco Hg-LH.     

Collection of Aerosol Particles by Electrostatic Droplet Spray Scrubbers

Theoretical calculations and experimental measurements show that the collection of small aerosol particles (0.05 to 5 micron diameter range) by water droplets in spray scrubbers can be substantially increased by electrostatically charging the droplets and particles to opposite polarity. Measurements with a 140 acfm two chamber spray scrubber (7 seconds gas residence time) showed an increase in the overall particle collection efficiency from 68.8% tit uncharged conditions to 93.6% at charged conditions, with a dioctyl phthalate aerosol (1.05 μm particle mass mean diameter and 2.59 geometric standard deviation). The collection efficiency for 0.3 μm particles increased from 35 to 87% when charged. During 1973–1974 a 1000 acfm pilot plant electrostatic scrubber was constructed inside a 40 ft trailer for evaluation on controlling particu-late emissions from pulp mill operations (funded by Northwest Pulp and Paper Association). Field tests performed on the particle emissions exhausting from SO₂ absorption towers treating the gases from a magnesium based sulfite recovery boiler have shown particle collection efficiencies ranging from about 60 to 99% by weight, depending on the electrostatic scrubber operating conditions. Energy requirements for the University of Washington electrostatic scrubber are about 0.5 hp/1000 acfm (350 Watts/1000 acfm) including gas pressure drop, water pressure drop, and electrostatic charging of the water spray droplets and the particles.     

Atomization and Cloud Behavior In Venturi Scrubbing

The exact collection mechanism of a venturi scrubber has been unknown up to this time. Photographic stop-action techniques and glass venturi scrubbers have made it possible to establish where and how particles are captured and to speculate on possible gas removal possibilities. This report extends the knowledge of pneumatic atomization which is used in gas scrubbing and many other applications by providing further information on cloud-type atomization. Cloud-type atomization which is produced by pneumatic atomization of liquid streams (not drops) results in the formation of liquid droplets which appear to be less than 10 microns in diameter. These droplets coalesce and form clouds which move as single entities. Effective overall cloud diameters are determined to be a function of the velocity of the atomizing gas stream. The effective cloud diameters start at 170 [a and increase as throat gas velocities increase from 150 ft/sec. Throat velocities and liquid inlet nozzle diameters necessary to obtain water clouds of specific effective diameters can be estimated.

These large clouds are efficient impaction targets and stop most of the particulate matter within 0.5 cm from the throat scrubbing liquid inlets. High gas absorption is expected for the clouds of droplets because turbulent gas movement can exist inside and outside the clouds and the 10 μ droplets provide exceptional surface area.     

Airborne Particulate Emissions from a Chromic Acid Anodizing Process Tank

Particulate mass concentration, particle size distribution, and particle chemical composition measurements have been conducted on the gases exhausting from a chromic acid anodizing process tank. Particle mass concentrations in the 200 to 20,000 μg/m³ range were measured using open-faced filters (47 mm diameter) adjacent to the process tank liquid and with closed filters (90 mm diameter) in the exhaust duct. Particle size distributions, measured using University of Washington Mark 3 and Mark 20 Cascade Impactors, showed the particle aerodynamic mass median diameter was about 3 microns. Chemical analysis of the particle samples obtained by the Modified EPA Method 5 sampling train, the Mark 20 UW Cascade Impactors, and by the 47 mm and 90 mm diameter filters showed Cr⁺⁶ concentrations in the 20 to 1,500 μg/m³ range with over 99 percent of the chromium in particles larger than 1.0 microns diameter. An integrating nephelometer was used to measure the light scattering coefficient of the exhaust gases upstream of the wet scrubber. The light scattering coefficient increased by a factor of about 2–3 over the background level during the 40 minute time period while a part was being anodized. The bscat values ranged from 3 × 10^?5 to 3 × 10^?4 meters^?1 for the aerosol particles less than about 6 microns aerodynamic diameter.     

Drop size-dependent chemical composition of clouds and fogs. Part II: Relevance to interpreting the aerosol/trace gas/fog system

Size-resolved fog drop chemical composition measurements were obtained during a radiation fog campaign near Davis, California in December 1998/January 1999 (reported in Reilly et al., Atmos. Environ. 35(33) (2001) 5717; Moore et al., Atmos. Environ. this issue). Here we explore how knowledge of this size-dependent drop composition—particularly from the newly developed Colorado State University 5-Stage cloud water collector—helps to explain additional observations in the fog environment. Size-resolved aerosol measurements before and after fog events indicate relative depletion of large (>2 μm in diameter) particles during fog accompanied by a relative increase in smaller aerosol particle concentrations. Fog equivalent air concentrations suggest that entrainment of additional particles and in-fog sedimentation contributed to observed changes in the aerosol size distribution. Calculated deposition velocities indicate that sedimentation was an important atmospheric removal mechanism for some species. For example, nitrite typically has a larger net deposition velocity than water and its mass is found preferentially in the largest drops most likely to sediment rapidly. Gas–liquid equilibria in fog for NO₃⁻/HNO₃, NH₄⁺/NH₃, and NO₂⁻/HONO were examined. While these systems appear to be close to equilibrium or relative equilibrium during many time periods, divergences are observed, particularly for low liquid water content (<0.1 g m⁻³) fogs and in different drop sizes. Knowledge of the drop size-dependent composition provided additional data useful to the interpretation of these deviations. The results suggest that data from multi-stage cloud water collectors are useful to understanding fog processes as many depend upon drop size.     

Assessment and optimisation of VOC mass transfer enhancement by advanced oxidation process in a compact wet scrubber

Dimethyl disulphide (DMDS) removal was investigated in a compact scrubber (hydraulic residence time ≈20 ms), composed of a wire mesh packing structure where liquid and gas flow at co-current and high gas superficial velocity (>12 m s⁻¹). In order to regenerate the scrubbing liquid and to maintain a driving force in the scrubber, ozone and hydrogen peroxide were added to water since they allow the generation of nonselective and highly reactive species, hydroxyl radicals HO. Three ways of reagent distribution were tested. The influence of several parameters (liquid flow rate(s), ozone flow rate, pH and reagent concentrations) was investigated. The best configuration was obtained when ozone is transferred in the scrubbing liquid before introduction at the top of the scrubber simultaneously with the hydrogen peroxide solution, allowing to generate hydroxyl radical in the scrubber. With this configuration, DMDS removal could be increased from 16% with water to 34% at the same gas and liquid flow rates in the scrubber showing the potentiality of advanced oxidation process.     

Spray Charging and Trapping Scrubber for Fugitive Particle Emission Control

The control of fugitive process emissions (FPE) with Spray Charging and Trapping (SCAT) scrubber was evaluated both theoretically and experimentally. The SCAT uses air curtain and/or jets to contain, convey, and divert the FPE into a charged spray scrubber.

Experiments were performed on an 8000 cfm bench-scale spray scrubber to verify the theory and feasibility of collecting fugitive particles with charged water spray. The effects of charge levels on drops and particles, nozzle type, drop size, gas velocity, and liquid/gas ratio on collection efficiency were determined experimentally. The results of the experiments and the comparison between theory and data are presented.

An air curtain was developed for conveying the FPE to the spray scrubber, deflecting the crosswind, and containing hot buoyant plume. The design and air flow field for the air curtain are presented.     

Note On The Collection of Lint Fly by Wet Impingement

A combined water scrubber-impinger was used to control lint cleaner effluent from machine-stripped short staple (11/16-13/16 in.) cotton because of its high efficiency and low pressure drop. The 8 × 4 × 4 ft rectangular scrubber could handle a maximum of 8000 CFM entering air at 80°F, 20% relative humidity and 0.7 g particulates/m³ with a 1-sec residence time at a maximum pressure drop of 0.5 in. of water across the chamber. Water to the chamber’s 6 doublespray and 2 single-spray nozzle taps was supplied from recycle and makeup sources at pressures of 7.5–30 psig with total flows of 21.8–31.1 gpm depending on number of nozzle taps in use. These sprays effectively wetted the particulate- laden air and provided enough water to wash the collected particulate matter down the chamber walls. The four WR-10 nozzles used at the base of the scrubbing chamber provided fine conical spray patterns co-current with the air flow. The two sets of four F-20 nozzles used in the center portion of the chamber provided coarse flat sheet sprays perpendicular to the air flow path. Two large TR-50 nozzles at the top of the chamber provided the necessary coarse conical sprays to wash the collected particulates down the chamber wall to the trash-water separator below. Water flows through the nozzles were determined from pressure readings at each tap. Chamber pressure drop was determined by 15° inclined manometer readings taken across the chamber at the locations where the air inlet and outlet mean square velocities occurred.     

An efficient venturi scrubber system to remove submicron particles in exhaust gas

An efficient venturi scrubber system making use of heterogeneous nucleation and condensational growth of particles was designed and tested to remove fine particles from the exhaust of a local scrubber where residual SiH4 gas was abated and lots of fine SiO2 particles were generated. In front of the venturi scrubber, normal-temperature fine-water mist mixes with high-temperature exhaust gas to cool it to the saturation temperature, allowing submicron particles to grow into micron sizes. The grown particles are then scrubbed efficiently in the venturi scrubber. Test results show that the present venturi scrubber system is effective for removing submicron particles. For SiO2 particles greater than 0.1microm, the removal efficiency is greater than 80-90%, depending on particle concentration. The corresponding pressure drop is relatively low. For example, the pressure drop of the venturi scrubber is approximately 15.4 +/- 2.4 cm H2O when the liquid-to-gas ratio is 1.50 L/m3. A theoretical calculation has been conducted to simulate particle growth process and the removal efficiency of the venturi scrubber. The theoretical results agree with the experimental data reasonably well when SiO2 particle diameter is greater than 0.1 microm.     

Inactivation of airborne Enterococcus faecalis and infectious bursal disease virus using a pilot-scale ultraviolet photocatalytic oxidation scrubber

High microbial concentrations and emissions associated with livestock houses raise health and environmental concerns. A pilot-scale ultraviolet photocatalytic oxidation (UV-PCO) scrubber was tested for its efficacy to inactivate aerosolized Enterococcus faecalis and infectious bursal disease virus (IBDV). Microbial reduction was determined by the difference in microbial concentrations measured in the upstream and downstream isolators that were connected to the two ends of the UV-PCO scrubber. Two UV irradiance levels were tested by using one or two UV lamps. The theoretical average UV irradiances were 6,595 µ W cm^?2 with one UV lamp and 12,799 µ W cm^?2 with two UV lamps. At the tested ventilation rate (70 m³ hr^?1), the contact time was 1 sec. Reduction rate and other two indexes (k-value and Z-value) that normalized UV radiation were calculated to describe the extent of microbial inactivation. The UV-PCO scrubber eliminated >99.7% of airborne E. faecalis from the incoming airstream under one UV lamp irradiance, and the reduction was further increased by 0.2–0.3% when the second UV lamp was added. The reduction rate for airborne IBDV was 72.4% with one UV lamp. The calculated k-values were 0.501–0.594 cm² mJ^?1 for airborne E. faecalis and 0.217 cm² mJ^?1 for IBDV. The Z-value of airborne E. faecalis to UV irradiance was 9.3 (±1.6)?×?10^?4 cm² µ W^?1 sec^?1. The results indicate that a UV-PCO scrubber can serve as an effective and efficient technology for inactivating airborne bacteria and virus. Scaling up of the pilot-scale scrubber for field use will require considerations such as design air treatment capacity, UV irradiance level, contact time, dust concentration, susceptibility of target microorganisms, and expected reduction rate.

Implications: This work demonstrated that a UV-PCO scrubber can be used to inactivate animal-associated airborne microorganisms, thus reducing microbial emissions from livestock houses and minimizing the biological impact to ambient environment. The microbial reduction efficiency by the UV-PCO scrubber varied depended on the level of UV irradiation and the target microbial species. The tested viral species (infectious bursal disease virus) was more resistant to the UV-PCO scrubber as compared to its counterpart bacterial species (E. faecalis).     

High-volume Impactor for Sampling Fine and Coarse Particles

Final design, calibration, and field testing have been completed for a new 1.13 m³/min (40 cfm) High-volume Virtual Impactor (HVVI). Field tests have demonstrated that the new classifier/collector works well as an accessory to the existing PM10 Size Selective Inlet high-volume samplers. The HVVI provides two fractions of PM10 mass, both of which are collected by filtration. The fine fraction (0-2.5 μm aero. dia.) Is collected on the standard 20.3 × 25.4 cm (8- × 10-in) high-volume filter; the coarse fraction (2.5-10 μm aero. dia.) is collected on a 5.1 × 15.2 cm (2- × 6-in) filter. Coarse flow through the receiver tubes is limited to 0.057 m³/min (2 cfm), 5 percent of the total flow.

The operating pressure drop across the HVVI stages Is sufficiently high to make changes In pressure across the collection filters Insignificant. The HVVI filter holder assembly facilitates loading/ unloading samples in the laboratory, thus eliminating damage due to handling filters in the field. Size separation characteristics of the HVVI agree well with those for the 16.7 L/min commercially available dichotomous sampler with the 50 percent effectiveness (cut-point) occurring at 2.5 μm. Applying laboratory-determined particle losses to the typical ambient particle mass size distribution described In Federal Register 49, 40 CFR, Part 53, Table D-3, the HVVI fine fraction total mass loss is less than 0.8 percent for liquid particles and less than 0.1 percent for solid particles; coarse fraction total mass loss is less than 2.5 percent for liquid particles, and less than 0.2 percent for solid particles.     

Performance Characteristics of a Regenerative Catalytic Oxidizer for Treating VOC-Contaminated Airstreams

ABSTRACT

A pilot apparatus of a regenerative catalytic oxidizer (RCO) equipped with two electrical heaters and two 20-cm i.d. × 200-cm height regenerative beds was used to treat methyl ethyl ketone (MEK) and toluene, respectively, in an airstream. The regenerative beds were packed with gravel (approximate particle size 1.25 cm, specific area 205 m²/m³, and specific heat capacity 840 J/kg °C) as a solid regenerative material and K-type thermal couples for measuring solid and gas temperatures, respectively. The catalyst bed temperature was kept around 400 °C and the gas superficial velocity was operated at 0.234 m/sec. This investigation measured and analyzed distributions of solid and gas temperatures with operating time and variations of volatile organic compound (VOC) concentrations in the regenerative beds. The overall VOC removal efficiency exceeded 98% for MEK and 95% for toluene. Degradation of VOCs will exist for MEK on the surface of solid material (gravel) in the temperature range of 330-400 °C, but toluene does not exhibit this phenomenon.     

Modeling the Reduction of Vapor Phase Emissions from Surface Soils Due to Soil Matrix Effects: Porosity/Tortuosity Concepts

ABSTRACT

A major route for transport of volatile organic compounds within porous media is vapor phase diffusion. The diffusion rate through a porous medium is less than that through free-air due to the decreased cross-sectional area available for gas movement and the increased path length due to pore tortuosity. Numerous empirical expressions have been published that relate the diffusion coefficient in porous media to the diffusion coefficient in free-air (unobstructed gas phase). Published measurements of relative diffusivity and air-filled porosity were combined into a database. Empirical expressions available in the literature, including the popular Millington-Quirk equation, were evaluated along with a fourth-degree polynomial expression developed by the authors to determine the best type of equation to predict relative diffusivity as a function of air-filled porosity over the domain of values for porosity ranging from 0.071 to 1 for different types of materials. Mean square deviations were used as the statistical test to compare equations. The polynomial expression developed in this project produced a significantly different effective diffusion coefficient (1.3 x 10^-6 m²/sec) compared to values of 9.2 x 10^-6 m²/sec and 3.1 x 10^-6 m²/ sec predicted by forms of the Millington-Quirk equation for a specific case.     

Gas Chromatographic Analysis of Incinerator Effluents

Comparative gas cleaning performance of a pilot-scale venturi scrubber with throat dimensions of 6 in. wide × 1 2 in. long × 1 2 in. deep was obtained for the following three methods of water injection: a system of spray nozzles located along each short side of the throat (Figure 2a); a continuous slot located immediately above the nozzles, along each short side of the throat (Figure 2b); and a weir located 2 ft above the spray nozzles along long side of the throat (Figure 2c). For each method of water injection the gas cleaning performance, as a function of the pressure drop, was measured by two tests: absorption of SO₂ and collection efficiency for particles of methylene blue of controlled size.     

Optimization of a wet scrubber with electrolyzed water spray—Part I: Ammonia removal

Electrolyzed water (EW) is an effective disinfectant with a wide range of pH. EW in acid range was proved to be an ammonia absorbent which make it valuable for wet scrubbers used in animal feeding operations (AFOs). This study aimed to optimize the design and operating parameters of a wet scrubber with EW spray for ammonia removal, based on the size distribution of droplets, the property of EW and the reduction efficiency of ammonia. The optimized parameters included droplet size, nozzle flow rates, pH and available chlorine concentration (ACC) of EW, nozzle number at single stage, stage number, initial ammonia concentration and air speed in the duct. The ammonia removal efficiency increased with the decrease of droplet size and the increase of flow rate. The pH values of EW showed significant influence on ammonia removal efficiency (P ? 0.05), while ACC of the EW showed no significant influence (P > 0.05). For inlet ammonia concentration of 70 ppm with one and three spray stages, the wet scrubber with EW (pH = 1.35) spray was able to reduce 55.8 ± 4.3 % and 97.2 ± 3.0 % of ammonia, respectively, when the nozzles with 0.9 mm orifice diameter operated at a flow rate of 1.20 L min^-1. Response surface analysis showed that orifice diameter, nozzle flow rate, and their combination were all significant factors impacting ammonia removal efficiency for both pH =1.35 and 5.50 at a 95% confidence level. Optimal ammonia removal efficiency was obtained at orifice diameter 0.9 mm and flow rate 1.20 L min^-1 within the selected range. The results of this study demonstrated that wet scrubber with EW spray could be a very effective and feasible ammonia mitigation technology for animal feeding operation.

Implications: It is difficult to effectively reduce ammonia emitted from the animal feeding operations (AFOs). Both the acidity and disinfection effects of electrolyzed water (EW) make it a potential absorbent used for spray in wet scrubber to reduce the ammonia and microorganisms. Based on some preliminary field test results, lab tests were conducted to optimize the design and operation parameters of a wet scrubber with EW spray to improve the ammonia removal efficiency. A better understanding of the application and influence factors of the wet scrubber with EW spray can contribute to effective mitigation of ammonia emission from animal houses and improve the atmosphere air quality.