Browsing by Author "Huang, CP"

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Adsorption behavior of iron-cyanide onto gamma-Al2O3 interface: A coagulation approach
(1999-05-01)
Cheng, WP
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Huang, CP
;
Pan, JRS
;
環境工程研究所
;
Institute of Environmental Engineering
Ferrocyanide and ferricyanide ions have strong coagulation ability in a natural water system due to their high valences. Studies with aluminum oxide turbid waters showed significant differences in coagulation between simple ions (Cl-, SO42-, Fe(CN)(6)Fe3-(CN)(6)(4-)) and other species (H2PO4-) that interact chemically with the oxide surface. The evidence suggested that the adsorption of ferrocyanide and ferricyanide on aluminum oxide surface is an outer-sphere reaction. The linear relationship between the logarithm of the significant coagulation concentration and Schultz-Hardy ratios indicated that the coagulation obeyed the DLVO rule. Therefore, it is concluded that the coagulation of aluminum oxide by ferrocyanide and ferricyanide is essentially caused by compression of the electric double layer rather than by charge neutralization. (C) 1999 Academic Press.
Adsorption characteristics of dichlorvos onto hydrous titanium dioxide surface
(1996-07-01)
Lu, MC
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Roam, GD
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Chen, JN
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Huang, CP
;
環境工程研究所
Adsorption of dichlorvos (2,2-dichlorovinyl-o,o-dimethl phosphate) onto hydrous TiO2 from water was evaluated in the laboratory using a batch reactor. The presence of organic solvents resulted in a decreasing dichlorvos adsorption on TiO, surface. These data were used to assess a cosolvent model. Decreased adsorption of dichlorvos was observed at an initial pH of 4 with increasing ionic strength. The inhibitory adsorption is attributed to the blockade of surface sites by electrolytes. In addition, electrolytes play an important role on the pa-dependent dichlorvos adsorption. It is suggested that at pH < pH(pzc) (point of zero charge), dichlorvos adsorption is inhibited because electrolytes compete with dichlorvos fbr surface sites. At pH > pH(pzc) the adsorption density of dichlorvos decreases with increasing solution pH due to the decrease of surface group, TiOH, on the TiO2 surface. The variation of adsorption density with temperature over the range 10 degrees-40 degrees C has been investigated. Results show that the reaction is controlled by enthalpy. The adsorption of dichlorvos onto the TiO2 surface is primarily brought about by hydrogen bonding. Copyright (C) 1996 Elsevier Science Ltd
Adsorption characteristics of iron-cyanide complex on gamma-Al2O3
(1996-08-10)
Cheng, WP
;
Huang, CP
;
環境工程研究所
;
Institute of Environmental Engineering
The adsorption behavior of ferrocyanide and ferricyanide toward aluminum oxide with a 0.01 M NaClO4 background electrolyte at 25 degrees C was investigated. Results obtained from different pH values demonstrated that the adsorption of these complex ions could be described by a modified Langmuir isotherm in the concentration range 0.5 X 10(-4) to 4 X 10(-4) M. This modified Langmuir isotherm developed here could accurately predict the equilibrium partition between solid and liquid phases while taking proton competition into account. Also, the apparent equilibrium constant (K-app) derived from the Langmuir equation for ferrocyanide or ferricyanide adsorption on aluminum oxide was compared with the intrinsic constant (K-int) calculated by triple-layer model simulation. This comparison revealed a strong correlation between the apparent equilibrium constant and the intrinsic constant. Moreover, in comparing K-app with K-int, we can infer that the adsorption of either ferrocyanide or ferricyanide complexes onto aluminum oxide is achieved through outer-sphere complexation. (C) 1996 Academic Press, Inc.
Adsorption characteristics of iron-cyanide complex on gamma-Al2O3
(1996-08-10)
Cheng, WP
;
Huang, CP
;
環境工程研究所
;
Institute of Environmental Engineering
The adsorption behavior of ferrocyanide and ferricyanide toward aluminum oxide with a 0.01 M NaClO4 background electrolyte at 25 degrees C was investigated. Results obtained from different pH values demonstrated that the adsorption of these complex ions could be described by a modified Langmuir isotherm in the concentration range 0.5 X 10(-4) to 4 X 10(-4) M. This modified Langmuir isotherm developed here could accurately predict the equilibrium partition between solid and liquid phases while taking proton competition into account. Also, the apparent equilibrium constant (K-app) derived from the Langmuir equation for ferrocyanide or ferricyanide adsorption on aluminum oxide was compared with the intrinsic constant (K-int) calculated by triple-layer model simulation. This comparison revealed a strong correlation between the apparent equilibrium constant and the intrinsic constant. Moreover, in comparing K-app with K-int, we can infer that the adsorption of either ferrocyanide or ferricyanide complexes onto aluminum oxide is achieved through outer-sphere complexation. (C) 1996 Academic Press, Inc.
Adsorption of Cu(II) and Ni(II) by pelletized biopolymer
(1996-02-01)
Huang, CP
;
Chung, YC
;
Liou, MR
;
交大名義發表
;
環境工程研究所
Chitosan and Ca-alginate, derivatives of biopolymer, were separately prepared from crab chitin and algin in pellet form for adsorption of Cu(II) and Ni(II) from aqueous solutions. The capability of these biopolymers was also investigated to remove copper and nickel from aqueous solutions in an immobilization system, along with a comparison made of these biopolymers with other adsorbents. Additionally, the feasibility of alginate/chitosan in pellets to remove nickel ion and nickel cyanide complex from polluted water was investigated. Stabilizing chitosan physically in an alginate support medium was deemed possible, by means of which both free metal and metal cyanide ions could be removed from aqueous solutions in an engineering system. However, the crosslinking reaction during immobilization would result in blocking of some adsorption sites.
Analysis for Giardia cysts and Cryptosporidium oocysts in water samples from small water systems in Taiwan
(2001-02-01)
Hsu, BM
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Huang, CP
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Hsu, CLL
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環境工程研究所
;
Institute of Environmental Engineering
Giardia and Cryptosporidium have emerged as waterborne pathogens of concern. Twenty-six water samples were collected from small water systems in Taiwan and checked for the occurrence of both parasites. Water quality parameters and characteristics of the sampling sites were also recorded. The frequencies of occurrence for Giardia and Cryptosporidium were 46.2% for each; and their mean concentrations were 79.5 cysts/100 1 and 22.1 oocysts/100 1, respectively. The concentrations of oocysts and heterotrophic bacteria exhibited the highest correlation and followed the concentrations of the two protozoa. The water samples from sites with filtration devices had a lower oocyst concentration than those from sites without filtration devices, while no significant difference was found for cysts. The level of each parasite had no direct relationship with altitude. The cyst concentrations increased proportionally with the consumer population using the water systems. Risk assessment of the parasitic infections suggests that setting up disinfection devices in the small water systems would be needed.
Application of a supported iron oxyhydroxide catalyst in oxidation of benzoic acid by hydrogen peroxide
(1999-05-01)
Chou, SS
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Huang, CP
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環境工程研究所
;
Institute of Environmental Engineering
Oxidation of benzoic acid was studied via Fenton-Like reaction using an innovative supported gamma-FeOOH catalyst. The decomposition kinetics of hydrogen peroxide was investigated first. Oxidation of benzoic acid by hydrogen peroxide was performed to understand the effects of initial pH and hydrogen peroxide dosage. The treatment efficiency of benzoic acid at an initial pH of 3.2 was higher than at initial pHs of 6.0 and 10.0; this can be partly explained by reductive dissolution of gamma-FeOOH. Therefore, the extent of heterogeneous catalysis was evaluated. We found that the majority of oxidation occurred on the catalyst surface, with some occurred in the solution due to iron dissolution of the catalyst. (C) 1999 Elsevier Science Ltd. All rights reserved.
Application of Aspergillus oryzae and Rhizopus oryzae for Cu(II) removal
(1996-09-01)
Huang, CP
;
Huang, CP
;
環境工程研究所
;
Institute of Environmental Engineering
Biosorption of copper(II) by the untreated and acid-treated fungal biomass has been studied in both batch and column modes. Two species, Aspergillus oryzae and Rhizopus oryzae, were used in this study. A. oryzae mycelia (undergoing acid-washing) exhibit a clear advantage in Cu(II) removal, compared with other adsorbents. The acid-washing process can strongly enhance the adsorption capacity for A. oryzae mycelia. However, acid-washing does not alter the metal adsorption capacity of R. oryzae mycelia. The result indicates that acid-washing is not only a pretreatment step but also a regeneration step in the heavy metal removal process. These dual purposes, therefore, give the acid-washing biomass an indication of successful prospect. Cultivating A. oryzae in pellet form is an effective means of mycelium immobilization. The method established in this study provides the high-yield, uniformly-sized particles (2-3 mm in diameter), which are effective in solid-liquid separation. This pellet column can completely remove metals before breakpoint. After the breakpoint, a significant amount of Cu(II) removal over a long period has been observed. This is thought to be the result of intracellular uptake. Copyright (C) 1996 Elsevier Science Ltd
Application of Aspergillus oryzae and Rhizopus oryzae for Cu(II) removal
(1996-09-01)
Huang, CP
;
Huang, CP
;
環境工程研究所
;
Institute of Environmental Engineering
Biosorption of copper(II) by the untreated and acid-treated fungal biomass has been studied in both batch and column modes. Two species, Aspergillus oryzae and Rhizopus oryzae, were used in this study. A. oryzae mycelia (undergoing acid-washing) exhibit a clear advantage in Cu(II) removal, compared with other adsorbents. The acid-washing process can strongly enhance the adsorption capacity for A. oryzae mycelia. However, acid-washing does not alter the metal adsorption capacity of R. oryzae mycelia. The result indicates that acid-washing is not only a pretreatment step but also a regeneration step in the heavy metal removal process. These dual purposes, therefore, give the acid-washing biomass an indication of successful prospect. Cultivating A. oryzae in pellet form is an effective means of mycelium immobilization. The method established in this study provides the high-yield, uniformly-sized particles (2-3 mm in diameter), which are effective in solid-liquid separation. This pellet column can completely remove metals before breakpoint. After the breakpoint, a significant amount of Cu(II) removal over a long period has been observed. This is thought to be the result of intracellular uptake. Copyright (C) 1996 Elsevier Science Ltd
Application of optical monitor to evaluate the coagulation of pulp wastewater
(1998)
Chou, SS
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Lin, SC
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Huang, CP
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環境工程研究所
;
Institute of Environmental Engineering
Coagulation/flocculation process is an important part of the solid/liquid separation in a wastewater treatment plant. However, conventional methods to determine coagulant dosage have led to poor results in real-time dosing control for the highly changeable quality of influent. In this study, we employ the photometric dispersion analyzer (PDA) to assess the feasibility of monitoring pulp suspended solids coagulation in pulp wastewater by batch trials. The use of PDA in the batch system to monitor the coagulation of filamentous microorganisms is also included. Batch test results indicate that PDA monitoring is an effective technique to reflect the state of aggregation of filament- and fiber-type solids and, therefore, can provide as a reliable index for determining the optimal dosage. In addition, in our coagulant dosing control system, the monitoring point of PDA should be set at the effluent of the rapid mixing unit We also assess the feasibility using PDA monitoring in a continuous system simulating the wastewater treatment processes. Results demonstrate that stable PDA output can accurately reflect the changes of influent turbidity and coagulant dosage. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.
Automatic control for chemical dosing in laboratory-scale coagulation process by using an optical monitor
(1996-08-01)
Huang, CP
;
Liu, CB
;
交大名義發表
;
環境工程研究所
;
National Chiao Tung University
The feasibility of applying an optical monitor in the automatic control of coagulation was assessed in this study. Prior to simulation testing, a series of batch tests was performed to determine the optimum state of dosing corresponding to the monitor's output. The results indicate that floc density decreased as floc size increased under the same coagulant dosage. Moreover, ratio output of the monitor could provide an index for evaluating the change trend of flee size in flocculation and for predicting the potential of flee settling. An automatic control system was designed and connected to a laboratory-scale water treatment process. A computer in the automatic control system received all the ratio values with respect to the progressive dosing. After determining the dosage, the system terminated the function of control. This control system started performing a new test for determining another optimum dosage when the fluctuation of inflow turbidity was more than a designated value. Simulation tests demonstrated that the PDA monitor with a designed control system could be successfully applied in the on-line control of coagulation dosing. The recommended control parameters for the control system was also identified. Copyright (C) 1996 Elsevier Science Ltd
Automatic control for chemical dosing in laboratory-scale coagulation process by using an optical monitor
(1996-08-01)
Huang, CP
;
Liu, CB
;
環境工程研究所
;
Institute of Environmental Engineering
The feasibility of applying an optical monitor in the automatic control of coagulation was assessed in this study. Prior to simulation testing, a series of batch tests was performed to determine the optimum state of dosing corresponding to the monitor's output. The results indicate that floc density decreased as floc size increased under the same coagulant dosage. Moreover, ratio output of the monitor could provide an index for evaluating the change trend of flee size in flocculation and for predicting the potential of flee settling. An automatic control system was designed and connected to a laboratory-scale water treatment process. A computer in the automatic control system received all the ratio values with respect to the progressive dosing. After determining the dosage, the system terminated the function of control. This control system started performing a new test for determining another optimum dosage when the fluctuation of inflow turbidity was more than a designated value. Simulation tests demonstrated that the PDA monitor with a designed control system could be successfully applied in the on-line control of coagulation dosing. The recommended control parameters for the control system was also identified. Copyright (C) 1996 Elsevier Science Ltd
Behavior of membrane scaling during crossflow filtration in the anaerobic MBR system
(2006)
You, HS
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Huang, CP
;
Pan, JR
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Chang, SC
;
環境工程研究所
Fouling of membrane bioreactor (MBR) has been studied intensively. Because of the high concentration of carbonates, scaling can be a serious problem in anaerobic bioreactor, which attracts little attention. In this study, the wastewater was treated with an anaerobic process followed by either a submerged or a side-stream aerobic membrane reactor. The wastewater was spiked with calcium to investigate the effect of scaling on membrane filtration. Very little scaling was detected in the external membrane system (the side-stream MBR). Results from chemical cleaning of internal membrane system indicated that the flux decline caused by membrane scaling was far more severe than that by membrane fouling. However, the flux decline from membrane scaling can be effectively recovered by the chemical cleaning of EDTA and NaOCl. Fouling of membrane bioreactor (MBR) has been studied intensively. Because of the high concentration of carbonates, scaling can be a serious problem in anaerobic bioreactor, which attracts little attention. In this study, the wastewater was treated with an anaerobic process followed by either a submerged or a side-stream aerobic membrane reactor. The wastewater was spiked with calcium to investigate the effect of scaling on membrane filtration. Very little scaling was detected in the external membrane system (the side-stream MBR). Results from chemical cleaning of internal membrane system indicated that the flux decline caused by membrane scaling was far more severe than that by membrane fouling. However, the flux decline from membrane scaling can be effectively recovered by the chemical cleaning of EDTA and NaOCl.
Biodegradation of hydrogen sulfide by a laboratory-scale immobilized Pseudomonas putida CH11 biofilter
(1996-11-01)
Chung, YC
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Huang, CP
;
Tseng, CP
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環境工程研究所
;
生物科技學系
A heterotrophic Pseudomonas putida CH11 was isolated from livestock farming wastewater and applied for the treatment of H2S-containing gas. Extensive tests including removal characteristics, metabolic products, and removal efficiencies of H2S by P. putida CH11 were examined in batch and continuous systems. The optimum pH required to remove hydrogen sulfide was found in the range of 6-8. The maximum removal rate and the saturation constant were calculated to be V-m=1.36 g S/day . kg dry bead and K-s=45.9 ppm, respectively. The main metabolic product of H2S oxidation was determined to be elemental sulfur. When P. putida CH11 was immobilized within Ca alginate, the cells exhibited high H2S removal efficiency, in excess of 96%, at concentrations of hydrogen sulfide from 10 to 150 ppm (now rates of 36 and 72 L/h). These results suggest that P. putida CH11 immobilized within Ca alginate has the potential to be used as a H2S removal agent.
Biological elimination of H2S and NH3 from wastegases by biofilter packed with immobilized heterotrophic bacteria
(2001-06-01)
Chung, YC
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Huang, CP
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Tseng, CP
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環境工程研究所
;
生物科技學系
Biotreatment of various ratios of H2S and NH3 gas mixtures was studied using the biofilters, packed with co-immobilized cells (Arthrobacter oxydans CH8 for NH3 and Pseudomonas putida CH11 for H2S). Extensive tests to determine removal characteristics, removal efficiency, removal kinetics, and pressure drops of the biofilters were performed. To estimate the largest allowable inlet concentration, a prediction model was also employed. Greater than 95% and 90% removal efficiencies were observed for NH3 and H2S, respectively, irrespective of the ratios of H2S and NH3 gas mixtures. The results showed that H2S removal of the biofilter was significantly affected by high inlet concentrations of H2S and NH3. As high H2S concentration was an inhibitory substrate for the growth of heterotrophic sulfur-oxidizing bacteria, the activity of H2S oxidation was thus inhibited. In the case of high NH3 concentration, the poor H2S removal efficiency might be attributed to the acidification of the biofilter. The phenomenon was caused by acidic metabolite accumulation of NH3. Through kinetic analysis, the presence of NH3 did not hinder the NH3 removal, but a high H2S concentration would result in low removal efficiency, Conversely, H2S of adequate concentrations would favor the removal of incoming NH3. The results also indicated that maximum inlet concentrations (model-estimated) agreed well with the experimental values for space velocities of 50-150 h(-1). Hence, the results would be used as the guideline for the design and operation of biofilters. (C) 2001 Elsevier Science Ltd. All rights reserved.
Biotreatment of ammonia from air by an immobilized Arthrobacter oxydans CH8 biofilter
(1997-11-01)
Chung, YC
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Huang, CP
;
Tseng, CP
;
環境工程研究所
;
生物科技學系
A heterotrophic Arthrobacter oxydans CH8 that was capable of removing NH3 from NH3 containing gas was isolated from livestock farming wastewater. The A. oxydans CH8 was immobilized with calcium alginate packed into filter column. Metered NH3-containing gas was partially humidified and passed through the glass column. Extensive tests including the removal characteristics, the removal efficiencies, and the metabolic products of NH3 by A. oxydans CH8 were conducted. Additionally, the operation criteria for the biofilter was also established. NH3 removal capacities were elevated by the immobilized-cell (biological conversion) method and the BDST (bed depth service time) method (physical adsorption), respectively. The optimum temperature for removing NH3 was 30 degrees C, while the nitrification ability remained 80% at 40 degrees C. The high efficiency (>97%) in the removal of NH3 was attained at 36 L/h with pH control and was not decreased because of high NH3 inlet concentration. In addition, the high maximum removal rate (1.22 g of N/day.(kg of bead)) enhanced the use of the biofilter in industrial-scale NH3(g) pollution control. The ability to remove NH3 at high inlet concentration and temperature suggested that the immobilized A. oxydans CH8 biofilter has potential in processing NH3 gas.
Biotreatment of ammonia from air by an immobilized Arthrobacter oxydans CH8 biofilter
(1997-11-01)
Chung, YC
;
Huang, CP
;
Tseng, CP
;
環境工程研究所
;
生物科技學系
A heterotrophic Arthrobacter oxydans CH8 that was capable of removing NH3 from NH3 containing gas was isolated from livestock farming wastewater. The A. oxydans CH8 was immobilized with calcium alginate packed into filter column. Metered NH3-containing gas was partially humidified and passed through the glass column. Extensive tests including the removal characteristics, the removal efficiencies, and the metabolic products of NH3 by A. oxydans CH8 were conducted. Additionally, the operation criteria for the biofilter was also established. NH3 removal capacities were elevated by the immobilized-cell (biological conversion) method and the BDST (bed depth service time) method (physical adsorption), respectively. The optimum temperature for removing NH3 was 30 degrees C, while the nitrification ability remained 80% at 40 degrees C. The high efficiency (>97%) in the removal of NH3 was attained at 36 L/h with pH control and was not decreased because of high NH3 inlet concentration. In addition, the high maximum removal rate (1.22 g of N/day.(kg of bead)) enhanced the use of the biofilter in industrial-scale NH3(g) pollution control. The ability to remove NH3 at high inlet concentration and temperature suggested that the immobilized A. oxydans CH8 biofilter has potential in processing NH3 gas.
Biotreatment of ammonia in air by an immobilized Nitrosomonas europaea biofilter
(1998-06-01)
Chung, YC
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Huang, CP
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環境工程研究所
;
Institute of Environmental Engineering
The chemoautotrophic microorganism Nitrosomonas europaea has been utilized to remove gaseous ammonia in a continuous reactor Extensive tests including removal characteristics, metabolic products, and removal efficiencies of ammonia by N. europaea were conducted. The operational principles governing the biofilter and the question of the heterotroph contamination were also studied. The optimum pH value and operating temperature required to effectively remove ammonia were-found to be pH 7.5 and 30 degrees C, respectively. When the diluted inlet ammonia concentration was 10 or 20 ppm, the biofilter achieved a 99% removal efficiency after 4 days of operation. However, higher ammonia inlet concentrations and heterotroph contamination resulted in a lower removal efficiency. The results showed that the maximum removal rate and apparent saturation constant were 1.11 g-N/day/kg-bead and 63.67 ppm, respectively. The mainly metabolic product of ammonia oxidation was determined to be nitrite, but the conversion ratio was dependent on whether the contaminations by hererotrophic bacteria were present. A om an operating perspective, if the ammonia emission limit (i.e., 1 ppm) was to be achieved the maximum inlet concentration could not exceed 75 ppm. These results suggest that the immobilized Nitrosomonas europaea biofilter provides a significant potential for treating ammonia In the gaseous phase.
Biotreatment of H2S- and NH3-containing waste gases by co-immobilized cells biofilter
(2000-08-01)
Chung, YC
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Huang, CP
;
Tseng, CP
;
Pan, JR
;
環境工程研究所
Gas mixture of H2S and NH3 in this study has been the focus in the research area concerning gases generated from the animal husbandry and the anaerobic wastewater lagoons used for their treatment. A specific microflora (mixture of Thiobacillus thioparus CH11 for H2S and Nitrosomonas europaea for NH3) was immobilized with Ca-alginate and packed inside a glass column to decompose H2S and NH3. The biofilter packed with co-immobilized cells was continuously supplied with H2S and NH3 gas mixtures of various ratios, and the removal efficiency, removal kinetics, and pressure drop in the biofilter was monitored. The results showed that the efficiency remained above 95% regardless of the ratios of H2S and NH3 used. The NH3 concentration has little effect on H2S removal efficiency, however, both high NH3 and H2S concentrations significantly suppress the NH3 removal. Through product analysis, we found that controlling the inlet ratio of the H2S/NH3 could prevent the biofilter from acidification, and, therefore, enhance the operational stability. Conclusions from bioaerosol analysis and pressure drop in the biofilter suggest that the immobilized cell technique creates less environmental impact and improves pure culture operational stability. The criteria for the biofilter operation to meet the current H2S and NH3 emission standards were also established. To reach Taiwan's current ambient air standards of H2S and NH3 (0.1 and 1 ppm, respectively), the maximum inlet concentrations should not exceed 58 ppm for H2S and 164 ppm for NH3, and the residence time be kept at 72 s. (C) 2000 Elsevier Science Ltd. All rights reserved.
Biotreatment of hydrogen sulfide- and ammonia-containing waste gases by fluidized bed bioreactor
(2001-02-01)
Chung, YC
;
Huang, CP
;
Liu, CH
;
Bai, HL
;
環境工程研究所
Gas mixtures of H2S and NH3 are the focus of this study of research concerning gases generated from animal husbandry and treatments of anaerobic wastewater lagoons. A heterotrophic microflora (a mixture of Pseudomonas putida for H2S and Arthrobacter oxydans for NH3) was immobilized with Ca-alginate and packed into a fluidized bed reactor to simultaneously decompose H2S and NH3. This bioreactor was continuously supplied with H2S and NH3 separately or together at various ratios. The removal efficiency, removal rate, and metabolic product of the bioreactor were studied. The results showed that the efficiency remained above 95% when the inlet H2S concentration was below 30 ppm at 36 L/hr. Furthermore, the apparent maximum removal and the apparent half-saturation constant were 7.0 x 10(-8) gS/cell/day and 76.2 ppm, respectively, in this study. The element sulfur as a main product prevented acidification of the biofilter, which maintained the stability of the operation. As for NH3, the greater than 90% removal rate was achieved as long as the inlet concentration was controlled below 100 ppm at a flow rate of 27 L/hr. In the NH3 inlet, the apparent maximum removal and the apparent half-saturation constant were 1.88 x 10(-6) g-N/cell/day and 30.5 ppm, respectively. Kinetic analysis showed that 60 ppm of NH3 significantly suppressed the H2S removal by Pseudomonas putida, but H2S in the range of 5-60 ppm did not affect NH3 removal by Arthrobacter oxydans. Results from bioaerosol analysis in the bioreactor suggest that the co-immobilized cell technique applied for gas removal creates less environmental impact.