H2S Removal Efficiency Research Articles

A new method for in-situ treatment of waste gas scrubbing liquid containing both NH3 and H2S based on sulfur autotrophic denitrification and partial nitrification-Anammox coupling system

In this study, an integrated device with scrubbing and biochemical treatment functions was used, and partial nitrification (PN)-Anammox and sulfur autotrophic denitrification (SADN) processes were coupled in a biochemical treatment pond to explore the feasibility of in-situ autotrophic removal of NH3 and H2S. The results showed that the removal efficiency of NH3 and H2S in waste gas are 95% and 87.5% respectively. The scrubbing liquid was efficiently treated in the biochemical treatment pond. Nitrogenous compounds weren’t accumulated in liquid and converted to N2 by SADN and PN-Anammox coupling system. S2− was mainly used by SADN process to reduce NO3−. The scrubbing liquid processed by the biochemical treatment pond was refluxed to the scrubber to achieve continuous absorption of NH3 and H2S. Microbial community and functional microbial analysis showed that the PN-Anammox and SADN processes were the main processes to achieve the conversion of pollutants in the scrubbing liquid.

Effect of Ce modification on desulfurization performance of regenerated sorbent for high temperature H2S removal from coal gas

Ce modified MnxOy/Al2O3-La have been prepared to investigate the effect of Ce loadings on pre-breakthrough H2S removal efficiency, breakthrough sulfur capacity (BSC) and BSC durability of the sorbents during desulfurization-regeneration cycles. The results showed Ce modification could improve the pre-breakthrough H2S removal efficiency of regenerated sorbents during desulfurization-regeneration cycles. The XPS characterization showed that the Ce can promote the binding energy of Mn ion to shift to lower energy, which enhanced H2S adsorption on the regenerated sorbent. However, the Ce loading sequence had effect on BSC durability of sorbent during desulfurization-regeneration cycles. The Ce-MnxOy/Al2O3-La with co-impregnation of Mn and Ce oxides had higher BSC than MnxOy/Al2O3-La, while the Ce/MnxOy/Al2O3-La with Ce loading on the surface of MnxOy/Al2O3-La had lower BSC and worse BSC durability than MnxOy/Al2O3-La. The characterization results showed Ce-MnxOy/Al2O3-La obtained better surface area and pore structure than MnxOy/Al2O3-La, and Ce ion can promote the increasing of the around electron density of Mn ion, which was beneficial for H2S adsorption of Ce-MnxOy/Al2O3-La. The poor surface area and pore structure would cause the low BSC of Ce/MnxOy/Al2O3-La, and less stability of pore structure might lead to poorer BSC durability of Ce/MnxOy/Al2O3-La than MnxOy/Al2O3-La during desulfurization-regeneration cycles.

Electrochemical mitigation of hydrogen sulfide in deep-pit swine manure storage.

Hydrogen sulfide (H2S) is a toxic and hazardous gas and is commonly present in livestock operations, which occasionally causes associated exposure accidents. This study evaluated the effectiveness of electrochemical control of H2S in lab-scale swine manure storage using different electrode materials, and further selected suitable materials to demonstrate the performance of a pilot-scale field test in the deep-pit manure storage of a 200-head swine barn. In the lab-scale test, electrochemical sulfide oxidation mainly contributed to the H2S mitigation, resulting in high H2S removal efficiencies when using low carbon steel (LCS) and stainless steel 304 (SS304) as electrodes. Based on their better H2S treatment performance and lower material costs, LCS and SS304 were selected for the pilot-scale test. In a 92-day operation, the pilot-scale demonstration showed H2S removal efficiencies of 84.0% and 63.5% for LCS and SS304, respectively. A techno-economic assessment indicated that the installation and operation of the electrochemical system accounted for 16% of barn construction cost using LCS as electrodes. Further optimization may substantially decrease the electrode material consumption and the overall cost.

Novel low-temperature H2S removal technology by developing yellow phosphorus and phosphate rock slurry as absorbent

Recycling hazardous gas of H2S is one of the most important strategies to promote sustainable development. Herein, a novel method regarding purifying H2S is proposed by using yellow phosphorus and phosphate rock slurry as absorbent. The H2SO4, formed in situ by H2S conversion, can be devoted to decompose phosphate rock, and the spent absorption slurry was applied as raw material for the production of phosphorus chemical products. According to the characterization analysis, it was found that H2S was first oxidized to SO2 via O2 as well as O3 induced by P4. Subsequently, the generated SO2 dissolved rapidly in water to form H2SO4, and then reacted with the main component of phosphate rock, CaMg(CO3)2. Most notably, the active substances, such as, O3, SO4•- and OH•, produced in the reaction process, can oxidize H2S and HS- to these sulfur products. In addition, trace amounts of Fe3+ and Mn2+ that were dissolved from phosphate rock displayed a promotional effect on the formation of active substances. Consequently, as high as 85% of H2S removal efficiency can be obtained even under acidic condition and low temperature. The proposed H2S purification method offers a promising option for sulfur recovery and H2S pollution control.

Relationship between heavy metal consolidation and H2S removal by biochar from microwave pyrolysis of municipal sludge: effect and mechanism.

The synergistic effects of pyrolysis byproduct, biochar (BC) on heavy metal consolidation, and H2S removal during and after from microwave pyrolysis of municipal sludge were studied in this paper. The results showed that above 80% of heavy metals (Zn and Pb) were enriched in the biochar and the leaching toxicity of both heavy metals was lower than the national emission standards. The chemical specification analysis found the sum of acid-soluble/exchangeable fraction (F1) and reducible fraction (F2) for Pb and Zn metals decreased by 26 and 40%; however, the residual fraction (F4) increased 33 and 46%, which contributed to the good stabilization of heavy metals in biochar. Besides, biochar achieved high H2S removal efficiency of 78.4% compared with the commercial activated carbon (AC). Furthermore, the biochar prepared by microwave pyrolysis had excellent adsorption performance, which was attributed to its larger specific surface area of 476.87m2/g under nitrogen atmosphere at 650oC compared with traditional pyrolysis. The mechanism analysis showed that microwave pyrolysis resulted in the high alkaline condition and formation of a large number of microparticles containing large metal elements on the biochar surface, which mainly contributed to the stabilization of heavy metals. The metal oxides adsorbed on the surface of biochar can catalyze the oxidation of H2S absorption, which will change the pH atmosphere of biochar reducing the leaching behavior of heavy metals. This study provided the good application potential of solid waste (biochar) for simultaneous heavy metal stabilization and H2S capture.

Catalytic Conversion for Hydrogen Sulfide

In this study, a series of transition metal mono-substituted heteropoly compounds H7PMo11MO39 (M = Co2+, Mn2+, Ni2+ and Zn2+) (HPMo11M) and single-absent heteropoly compounds H3PMo11O39 (HPMo11) were prepared for highly effective removal of hydrogen sulfide (H2S) from gas stream. The heteropoly compounds were characterized Fourier transform infrared spectroscopy (FT-IR), elemental analysis and scanning electron microscopy (SEM). The results confirmed that the transition metal ions successfully replaced the Mo atom. H7PMo11CoO39 showed that the outstanding desulfurization capacity and the H2S removal efficiency can reach more than 90% for 3 h. Besides, after regeneration, the desulfurization capacity of H7PMo11CoO39 towards H2S only a drop of 5.11% of the initial desulfurization capacity. Optimization experiments demonstrated that H7PMo11CoO39 had the ideal desulfurization performance under the condition of low H2S concentration or high dosage of H7PMo11CoO39. An appropriate temperature of 25°C is necessary for high removal efficiency. The optimum pH value for desulfurization is 5. The kinetic data can be well described by pseudo-first-order kinetic model. The desulfurization products were proved to be S and SO42– based on X-ray photoelectron spectroscopy (XPS) characterization results.

Use of compost as biological filter to remove gaseous hydrogen sulfide

Odor pollution is very popular in developing countries. Odors can arise from many different sources, cause discomfort to expose, and also have certain effects on health. Odors can come from the anaerobic digestion of waste, from a factory's wastewater treatment system, or from manufacturing operations in industries such as seafood processing or animal feed production, tanning, and rubber processing. The composition of the odor is often diverse with many gases, mainly in low concentrations. Because it is gaseous pollution, the odor has the risk of spreading widely, the collection must be carried out in a wide range, the flow of gas to be treated is often large. In this study, one of the basic components of odors, H2S, was of interest to be treated because of its prevalence and toxic nature. Currently, although there are many technologies to handle H2S, the application in odor treatment still has many shortcomings. The current technologies such as adsorption and absorption are not suitable for the removal of H2S in odor because of the low efficiency but high cost. In this study, a cheap and available commercial compost fertilizer was used for the removal of gaseous H2S in a lab-scale biofilter. Results showed that microorganisms had an avital role in H2S removal. The factors affecting the biological removal of H2S were determined to be relative humidity (RH), operation time, presence of mixing/turning, and height of compost column. The high H2S removal efficiency of 94.2% was obtained at RH of 50% and compost height of 400 mm, which is suggested for full-scale biofilter design. Under turning condition of once per two days for compost column, the biofilter system was stable at removal efficiency of over 80% during at least 12 days of operation.

Nitrogen-modified Graphene Synthesis and Modification of H2S Removal Efficiency Comparison

In this paper, multilayer graphene is used as the raw material, graphene oxide is prepared by Hummers' improved method, and Nitrogen-modified Graphene is prepared by solvothermal method. It uses SEM, XRD, XPS, Ramman to characterize the sample morphology, internal composition, internal structure and element content, analyze its chaos and functional group change trend, and get: graphene to graphene oxide to Nitrogen-modified Graphene, graphene oxide The replacement of C atoms by O atoms increases surface wrinkles and increases defects and confusion. Nitrogen-modified Graphene is reduced due to the oxygen-containing functional groups of graphene oxide, reducing functional groups and reducing interlayer materials, resulting in a clean surface and reduced defects. The layer spacing is reduced. Then through a fixed bed reactor, using graphene, graphene oxide, and Nitrogen-modified Graphene as experimental samples, the adsorption of hydrogen sulfide gas was tested and researched: the original graphene and graphene oxide had similar adsorption capacities for hydrogen sulfide gas. Nitrogen-modified Graphene is about 3 times that of the first two experimental samples.

H2S oxidation coupled to nitrate reduction in a two-stage bioreactor: Targeting H2S-rich biogas desulfurization

A two-stage bioreactor operated under anoxic denitrifying conditions was evaluated for desulfurization of synthetic biogas laden with H2S concentrations between 2500 and 10,000 ppmv. H2S removal efficiencies higher than 95% were achieved for H2S loads ranging from 16.2 to 51.9 gS mliquid−3h−1. Average H2S oxidation performance (fraction of S-SO42− produced per gram of S-H2S absorbed) ranged between 8.2 ± 1.2 and 18.7 ± 5.3% under continuous liquid operation. Nitrogen mass balance showed that only 2–6% of the N-NO3− consumed was directed to biomass growth and the rest was directed to denitrification. Significant changes in the bacterial community composition did not hinder the H2S removal efficiency. The bioreactor configuration proposed avoided clogging issues due to elemental sulfur accumulation as commonly occurs in packed bed bioreactors devoted to H2S-rich biogas desulfurization.

Factors impacting the performance and microbial populations of three biofilters for co-treatment of H2S and NH3 in a domestic waste landfill site

Numerous volatile organic compounds and odors are generated when municipal solid wastes decompose in landfill sites. Three biofilters (BF-1, BF-2, and BF-3) were deployed to remove H2S and NH3 accumulated under high density polyethylene films in a 30,000 m2 area landfill site in North China. Results showed that the inlet concentrations of H2S and NH3 were 16.4–220.3 mg/m3 and 2.0–56.4 mg/m3, respectively. Outlet concentrations were reduced to 1.0–33.1 mg/m3 for H2S and 0–9.2 mg/m3 for NH3. The H2S removal efficiencies were around 91.1 % for BF-1, 87.0 % for BF-2, and 82.6 % for BF-3 in a steady state. The respective removals of NH3 were 92.0 %, 89.3 %, and 81.1 %. Thus, H2S and NH3 were both treated effectively by the biofilters. The intake load presented a seasonal variation. A high elimination capacity was obtained in the biofilter harvesting high inlet load. High throughput sequencing technology was utilized to assay the microbial populations in the biofilters. Pseudomonas sp., Alicyclobacillus sp., Sphingomonas sp., and Rhodanobacter sp, which were linked to the degradation of H2S and NH3, were isolated and identified. Their characteristics and distributions in the biofilters depended on the inlet concentration of substrates and the microenvironment within the packing materials. The results from this bio-product analysis indicated that most of H2S was bio-oxidized into sulfur and sulfate while NH3 was converted into nitrate or dissolved into the liquid phase mainly by absorption or chemical neutralization in the biofilters.

Predicting the performance of a desulfurizing bio-filter using an artificial neural network (ANN) model

The aim of this study was to develop a model for predicting the performance of a desulfurizing bio-filter (BF), without requiring prior information about H2S biodegradation kinetics and mechanism. A single hidden layer artificial neural network (ANN) model was developed and validated using the gradient descent backpropagation (GDBP) learning algorithm coupled with a learning rate and a momentum factor. The ANN model inputs were gas flow rate, residence time, and axial position in the BF bed. The removal efficiency of H2S was the model output. Various structures for ANN model, differing in the number of hidden layer neurons, were trained and an early stopping validation technique, the K-fold cross-validation, was used to determine the optimal structure with the best generalization ability. The modeling results showed that there was a good agreement between the experimental data and the predicted values, with a determination coefficient (R<sup>2</sup>) of 94%. This implies that the ANN model might be an attractive and useful alternative tool for forecasting the performance of desulfurizing BFs.

Development of scrubber with nano-TiO2 coated packing for H2S removal

A pilot-scale packed-bed wet scrubber with plastic packing materials was made and experimented to control hydrogen sulfide.TiO2 nanoparticles were coated on the surface of packing to improve the hydrophilicity of scrubbing liquid to form a homogeneous liquid layer on the packing surface. Air flow rate, H2S concentration, and liquid pH were selected to evaluate their effect on scrubber removal efficiency. To evaluate and model the effects of selected variables, two separate sets of experiments were designed and conducted using response surface methodology, central composite design. The former was to model the effects of air flow rate and H2S inlet concentration on removal efficiency at natural liquid pH, and the latter was aimed at total optimization, where all three variables were evaluated. Results showed that TiO2 nanoparticles substantially increased surface hydrophilicity and hydrogen sulfide removal efficiency in natural pH and total optimization by 3.12 % and 3.63 %, respectively. Moreover, air flow rate and H2S concentration had an adverse effect on H2S removal efficiency, while liquid pH positively influenced the efficiency. The optimum removal efficiency for natural pH and total optimizations were 98.83 % and 99.93 %, respectively. The results showed that hydrophilicity of packing materials has a strong effect on hydrogen sulfide removal.

A high efficient absorbent for the separation of H2S from low partial pressure coke oven gas.

To high efficiently remove H2S from low partial pressure coke oven gas (COG), a novel activator (tetramethylammonium arginine, [N1111][Arg]) was used to blend with N-methyldiethanolamine (MDEA) for the absorption of H2S. High concentrated [N1111][Arg]-MDEA aqueous solution was used as absorbent. Thermodynamic properties including absorption amount and H2S loading values were measured, then the kinetic apparent absorption rate was calculated based on the change of absorption amount with time. The removal efficiency of H2S in simulated COG was verified in tray towers. Compared with monoethanolamine (MEA)-MDEA and tetramethylammonium glycinate ([N1111][Gly])-MDEA aqueous solutions, [N1111][Arg]-MDEA aqueous solution takes advantages of higher absorption capacity, absorption rate and removal efficiency. Our results showed that the proposed absorbent has good industrial application prospect in coke oven gas desulfurization, because it achieved 100% removal of H2S in the tray tower containing only 4 sieve plates under high concentrated condition (water content < 45%), which may significantly decrease the energy consumption.

Electrolytic cell–assisted polyoxometalate based redox mediator for H2S conversion to elemental sulphur and hydrogen

This study proposed a novel electrolytic cell–assisted redox system based on lacunary-type polyoxometalate, which can simultaneously remove hydrogen sulphide (H2S), recover elemental sulphur, and produce hydrogen. In this redox system, H2S is oxidised into elemental sulphur by using polyoxometalate ([Sm(PMo(VI)11O39)2]−11), which is reduced to corresponding heteropoly blue (reduced polyoxometalates [Sm(PMo(IV)11O39)2]−55). Furthermore, heteropoly blue is electrochemically oxidised back into polyoxometalate on the anode surface, and hydrogen is produced on the surface of the cathode in an electrolytic cell. The experimental results indicated that a 94.8% H2S removal efficiency, and 77.9% sulphur recovery efficiency were achieved under optimum conditions. H2S was effectively converted to elemental sulphur in the proposed system. Moreover, Optical and electrochemical characterisations demonstrated that the structures of the lacunary-type polyoxometalate could be well-maintained at pH 5, which was most favourable for H2S removal. Notably, clean energy hydrogen could be produced in polyoxometalate regeneration process. This innovative system—combining H2S waste conversion to elemental sulphur, electrochemical regeneration of redox mediators, and hydrogen production and thus providing environmental benefits and significant economic value—may have future applications in commercial technology.

Simultaneous biofiltration of H2S and NH3 using compost mixtures from lignocellulosic waste and chicken manure as packing material.

Biofiltration offers an efficient and economical alternative for the elimination of offensive odors caused by hydrogen sulfide, ammonia, and volatile organic compounds. Considering that packing materials affect the performance and represent the main installation cost, the purpose of this work was to evaluate the biofiltration of H2S and NH3 comparing three composted mixtures made from chicken manure and lignocellulosic residues (pruning waste, sugarcane bagasse, and rice husk) used as packing material. A range of gas concentrations similar to those of a municipal WWTP was used in the biofiltration of a contaminated stream performed on a laboratory scale. The results indicate that at low concentrations of H2S (6-36 ppm) and NH3 (0-1 ppm), the three biofilters showed 100% removal efficiency. Now, at the maximum levels of gas concentrations of H2S (250 ppm) and NH3 (19 ppm) while the removal efficiency of H2S remained higher than 90% in all cases, the removal efficiency of NH3 remained higher than 90% only in the sugarcane bagasse biofilter. Compost mixtures with sugarcane bagasse and rice husk are highly reliable as packing material for biofiltration at high concentration of H2S. Specifically, the sugarcane bagasse mixture had the highest removal efficiency (99% H2S and 95% NH3) and the highest elimination capacity (15 g H2S/m3h and 0.6 g NH3/m3h), making it a better option for the elimination of both gases. These results represent a contribution to the construction of a low-price elimination system of offensive odors in WTTPs and other industries.

Comparing Hydrogen Sulfide Removal Efficiency in a Field-Scale Digester Using Microaeration and Iron Filters

Biological desulfurization of biogas from a field-scale anaerobic digester in Peru was tested using air injection (microaeration) in separate duplicate vessels and chemical desulfurization using duplicate iron filters to compare hydrogen sulfide (H2S) reduction, feasibility, and cost. Microaeration was tested after biogas retention times of 2 and 4 h after a single injection of ambient air at 2 L/min. The microaeration vessels contained digester sludge to seed sulfur-oxidizing bacteria and facilitate H2S removal. The average H2S removal efficiency using iron filters was 32.91%, with a maximum of 70.21%. The average H2S removal efficiency by iron filters was significantly lower than microaeration after 2 and 4 h retention times (91.5% and 99.8%, respectively). The longer retention time (4 h) resulted in a higher average removal efficiency (99.8%) compared to 2 h (91.5%). The sulfur concentration in the microaeration treatment vessel was 493% higher after 50 days of treatments, indicating that the bacterial community present in the liquid phase of the vessels effectively sequestered the sulfur compounds from the biogas. The H2S removal cost for microaeration (2 h: $29/m3 H2S removed; and 4 h: $27/m3 H2S removed) was an order of magnitude lower than for the iron filter ($382/m3 H2S removed). In the small-scale anaerobic digestion system in Peru, microaeration was more efficient and cost effective for desulfurizing the biogas than the use of iron filters.

Hydrogen sulfide biological removal efficiency by vermicompost horizontal biofilter

To efficiently treat hydrogen sulfide (H2S) from contaminated air, we designed a fixed carrier horizontal biofilter. The biofilter system was packed with vermicompost as baffle plate. The inlet concentration and the thickness of media on the removal efficiency were studied. Furthermore, a final product analysis and the macro-kinetics of bio-degradation were also evaluated. The results showed that the horizontal biofilter can be started quickly, favorable removal efficiencies of H2S were proved and reached nearly100% when the inlet concentration lower than 350 mg m−3. The thickness of vermicompost affected the H2S removal efficiency. It was found that the nutrient elements of vermicompost increased, especially the sulfur increased significantly. In addition, in kinetic analysis, the semi-saturation constant and maximum removal rate of H2S were calculated to be 417.1 mg m−3 and 1428.6 g m−3 d−1. The results presented in this study the horizontal vermicompost biofilter was effective for removing H2S contaminated air, and will be valuable for further research and engineering applications.

Long-term influence of high alkalinity on the performance of photosynthetic biogas upgrading

The alkalinity of the cultivation medium plays a key role on photosynthetic biogas upgrading, exerting impact not only on the mass-transfer of CO2 and H2S in the biogas scrubbing column but also on the subsequent CO2 uptake or stripping to the atmosphere. The long-term performance of algal-bacterial processes devoted to the concomitant removal of CO2 and H2S from biogas in a 180 L open pond interconnected to a 2.5 L biogas scrubbing column via an external liquid recirculation of supernatant from a 8 L conical settler under process operation at high inorganic carbon (IC) concentrations was assessed. The influence of biomass concentration in the cultivation medium on process performance was also evaluated. CO2 concentrations in the upgraded biogas fluctuated between 1.5 and 4.4% at IC concentrations in the cultivation medium of 1200 mg C L−1, and remained almost constant (0.7 ± 0.1%) at IC concentrations > 2400 mg C L−1. However, the increase in the IC concentration from 1203 to 3476 mg C L−1 entailed an increase in C-CO2 stripping from 14.5 to 33.4% of the IC input to the system. The increase in biomass concentration from 0.33 to 1.38 g SSV L−1 entailed a reduction in CO2 removal of 1.1% even under process operation at high alkalinity. H2S removal efficiencies of 100% were achieved regardless the IC or biomass concentration.

Removing hydrogen sulfide from a feed stream using suitable adsorbent materials

A series of materials, including sand (S) silica blue (SB), iron-exchanged sand (IES), zeolite 13X (Z), iron-exchanged zeolites (IEZ), and the waste material acid mine drainage sludge (AMDS), were used as adsorbents for the removal of hydrogen sulfide (H2S) from a feed stream in a pilot (bench)-scale study. Artificially polluted H2S gas streams were created using a gas cylinder with 10,000 ppmv of H2S in nitrogen (N2), which was used for further dilution. The adsorption performance of each sorbent material was assessed by dynamic breakthrough analysis. The sorbents were analyzed via Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-Ray fluorescence spectrometry (XRF), X-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET) analysis. The efficiency of H2S removal was observed and compared between adsorbents under various operating conditions, such as different contact times and initial concentrations. The AMDS was discovered to have highest adsorption efficiency for H2S, of all adsorbents studied here. The Yoon-Nelson, Thomas and Adam-Bohart models were applied to study the effects of H2S concentration and flow rate on adsorption of H2S on AMDS, and the maximum adsorption capacity of 312.73 g g−1 was attained at 1000 ppmv and 0.5 L min−1 of H2S concentration and flow rate, respectively. This study found that all tested adsorbent materials have appreciable H2S adsorption capacity and AMDS in particular is an appropriate adsorbent for treatment of H2S-contaminated steam. Moreover, AMDS is a waste material and is available in abundance; hence, AMDS could be a practical choice for the adsorption of H2S from biogas.

Removal of H2S by vermicompost biofilter and analysis on bacterial community

AbstractThe vermicompost collected from dewatered domestic sludge as packing material in biofilter was investigated for hydrogen sulfide (H2S) removal. No nutrients or microbial inoculation was added throughout the experiment. The corresponding bacterial community characteristics in the vermicompost biofilter of different spatial levels were evaluated by Miseq high-throughput sequencing technique. The results showed that the vermicompost biofilter performed well during operation. The H2S removal efficiency reached nearly 100% under condition of the inlet concentration &lt;350 mg m−3 and 0.25−0.35 m3 h−1 gas flow rate. The maximum elimination capacity of 20.2 g m−3 h−1 was observed at a flow rate of 0.35 m3 h−1. Furthermore, the amounts of biodegraded products and pH varied accordingly. In addition, the results from high-throughput sequencing revealed pronouncedly spatial variation of the vermicompost, and the Rhodanobacter, Halothiobacillus, Mizugakiibacter as well as Thiobacillus, which can play an important role in removing H2S, were predominant in the final vermicompost. These results imply that the vermicompost with diverse microbial communities has a good potential for eliminating H2S.