H2S Loading Research Articles

Biofiltration performance and kinetic study of hydrogen sulfide removal from a real source.

Biofiltration is one of the most accepted technologies in odor control in wastewater facilities. A biofilter system consists of a bed of organic material providing both as the carrier for the active microorganisms and as nutrient supply. This study was aimed to evaluate and model a biofilter performance operated under real conditions of odor emission from a wastewater pump station located in Khorramabad, Iran. The media was a mixture of compost and wood chips with a weight ratio of 5:1. The treatment performance of the biofilter was assessed during a 90-day operation period and the gathered data were utilized to develop and determine the best fit kinetic model based on Michaelis-Menten and Ottengraf models. The best fit model was used in the analysis of scenarios defined based on inlet H2S loading fluctuations. Also, the effectiveness of the main parameters in biofilter performance was evaluated using a dimensionless sensitivity coefficient. The best fit model was found the Ottengraf zero-order type limited by diffusion based on the values of R-square (0.98) and mean square error (MSE) (0.002). The results demonstrated a high H2S removal efficiency of about 98% in an EBRT (empty bed residence time) of 60s. despite high fluctuations of inlet concentration under real conditions. The system was able to meet the effluent standard limit of 10ppm even if the inlet H2S loading increases up to two times the base level. According to the results of the defined sensitivity coefficient, the system performance was more sensitive to the inlet concentration than EBRT with a ratio of 1.4. In addition to the acceptable efficiencies of biofilter in odor removal, the results proved the worth of using a kinetic model in forecasting the system performance which is a useful tool in the design and operation of such systems.

Biological removal of H2S gas in a semi-pilot scale biotrickling filter: Optimization of various parameters for efficient removal at high loading rates and low pH conditions

In this study, a semi-pilot scale biotrickling filter (BTF) was operated in a continuous co-current mode to remove high concentration of hydrogen sulfide (H2S) at optimum operational conditions. The early startup period of 6 days was needed, and then stable removal of H2S gas at inlet concentrations up to about 2000 ppm was successfully obtained at gas retention time (GRT) of 15 min and liquid recirculation rate (LRR) of 120 ml/min. The elimination capacities (ECs) increased linearly with increase in H2S loading rates (HLRs up to 38.5 g/m3 h), but a gradual decrease in removal efficiency was observed from a volumetric HLR of 18.1 g/m3 h. The LRR was further decreased from 120 to 30 ml/min, and the minimum liquid–gas ratio of 0.24 was found without decrease in removal efficiency. The MiSeq analysis revealed the presence of sulphur oxidizing bacteria (SOB) dominated by Acidithiobacillus caldus (>97%) at all portions of BTF.

Study of Various Aqueous and Non-Aqueous Amine Blends for Hydrogen Sulfide Removal from Natural Gas

Various novel amine solutions both in aqueous and non-aqueous [monoethylene glycol (MEG)/triethylene glycol(TEG)] forms have been studied for hydrogen sulfide (H2S) absorption. The study was conducted in a custom build experimental setup at temperatures relevant to subsea operation conditions and atmospheric pressure. Liquid phase absorbed H2S, and amine concentrations were measured analytically to calculate H2S loading (mole of H2S/mole of amine). Maximum achieved H2S loadings as the function of pKa, gas partial pressure, temperature and amine concentration are presented. Effects of solvent type on absorbed H2S have also been discussed. Several new solvents showed higher H2S loading as compared to aqueous N-Methyldiethanolamine (MDEA) solution which is the current industrial benchmark compound for selective H2S removal in natural gas sweetening process.

Evaluation of a hybrid physicochemical/biological technology to remove toxic H2S from air with elemental sulfur recovery

The removal of toxic hydrogen sulfide (H2S) from the air at pilot-scale with elemental sulfur recovery was evaluated using Fe-EDTA chelate as a single treatment at a pH of about 8.5. This was later combined with a compost biofiltration process for polishing the pre-treated air. Experiments were performed in a unique container system that allowed deploying either Fe-EDTA chelate or Fe-EDTA chelate/biofiltration treatment (hybrid system). The results showed the feasibility of H2S removal at concentrations between 200 and 5300 ppmv (H2S loading rates of 7–190 g m−3 h−1) present in fouled air. The Fe-EDTA chelate as a single treatment was able to remove nearly 99.99% of the H2S at inlet concentrations ≤ 2400 ppmv (107 g m−3 h−1), while the hybrid system archived undetectable outlet H2S concentrations (<1 ppmv) at inlet levels of 4000 and 5300 ppmv. At 5300 ppmv, the Fe-EDTA chelate process H2S removal efficiency decreased to 99.20% due to the limitation of oxygen mass transfer in the Fe(III) regeneration reaction. Under the previous conditions, the pH was required to be controlled by the addition of NaOH, due to the likely occurrence of undesirable parallel reactions. The elemental sulfur yield attained in the physicochemical module was 75–93% with around 80% recovered efficiently as a solid.

Fully aerobic bioscrubber for the desulfurization of H2S-rich biogas

A fully aerobic bioscrubber for the desulfurization of H2S-rich biogas was developed in the present study by coupling an absorption column and a bubble column bioreactor. The bioscrubber treated H2S loading rates of 37, 59, and 100 g S mliquid−3 h−1 at gas residence times of 6.6, 4.1 and 2.4 min in the absorption column, respectively. Stable H2S removal efficiencies above 80% were recorded at all the conditions tested. The bioscrubber was robust towards short- and long-term operation shutdowns (5 and 18 days), the H2S removal performance being recovered after few hours. The aerated bubble column bioreactor was operated at slightly alkaline conditions (pH 8 ± 0.5), which prevented H2S stripping and allowed sulfur oxidation performances higher than 75% regardless of the operating conditions tested. Bacterial community characterization by 16S rRNA pyrosequencing revealed that the operating conditions (slightly alkaline pH, sulfate concentrations of up to 25,000 g m−3 and dilution rates of 5.7 × 10−3–8.6 × 10−3 h−1) shaped a specialized community highly efficient for H2S oxidation. Three Proteobacteria were predominant in the bubble column bioreactor, namely Thioalkalimicrobium cyclicum, Stappia sp. and Ochrobactrum sp. with relative abundances of 68.18, 13.49 and 7.61%, respectively.

Experimental and Kinetic Analysis of H2S Removal in a Polyurethane Foam/Palm Fiber-Based Biofilter with No pH Control

Exposure to hydrogen sulfide, a toxic and malodorous pollutant, is a public health concern. Therefore, its removal from polluted air streams is crucial. This study aimed to evaluate the removal of H2S in a biofilter packed with a mixture of polyurethane foam and palm fiber with no pH control. The kinetics of H2S biofiltration were also analyzed using Michaelis–Menten and Haldane models. The biofilter was operated for 72 days at empty bed retention times (EBRT) of 47 and 30 s. During the operation of the biofilter, in addition to measurement of inlet and outlet H2S concentrations, the concentration profiles along the reactor length were also monitored. Moreover, the sulfate contents and pH values of packing bed and leachate were measured. During H2S biofiltration, the sulfate contents of packing bed and leachate increased and the leachate was acidified. Under this condition, the biofilter provided removal efficiency (RE) > 99% for inlet H2S concentrations up to 380.0 mg m−3 at EBRT of 47 s. Moreover, a maximum elimination capacity (ECmax) of 36.0 g m−3h−1 with RE of 98.0% was obtained at EBRT of 47 s. The experimental EC values were better fitted to Haldane kinetic, indicating the inhibitory effect of high H2S loads on its removal in the biofilter without controlling pH and under acidic conditions. Overall, efficient removal of H2S was obtained in a polyurethane foam/palm fiber-based biofilter with negligible pressure drop even without controlling pH.

Biogas desulfurization under anoxic conditions using synthetic wastewater and biogas slurry

A feasibility study was conducted to determine whether aerated biogas slurry is a suitable nutrient solution for biogas desulfurization systems with a biotrickling filter. At a loading rate of 36.20 g-H2S m−3h−1, the H2S and NOx−-N removal efficiencies were 84.7% (average elimination capacity of 30.67 g-H2S m−3h−1) and 60.9%, respectively, when utilizing synthetic wastewater in a simultaneous biogas desulfurization and wastewater denitrification system. However, these efficiencies were just 61.9% (average elimination capacity of 22.42 g-H2S m−3h−1) and 49.2%, respectively, when biogas slurry was used. High-throughput sequencing revealed that the Thiobacillus and Sulfurimonas genera were the main functional bacteria. Alpha- and beta-diversity analyses showed that the H2S loading rate significantly affected the microbial community structure, especially in the system utilizing aerated biogas slurry. Finally, based on the results, we describe a feasible approach to using biogas slurry for biogas desulfurization.

Feedforward control application in aerobic and anoxic biotrickling filters for H2S removal from biogas

AbstractBACKGROUNDFeedforward control was implemented at laboratory scale in an aerobic and an anoxic biotrickling filter (BTF) operating under fluctuating H2S loading rate (LR) conditions in order to show the capabilities and added value of this control strategy. Dynamic, long‐term tests with variable H2S LR were performed to simulate disturbances in the inlet gas concentration with and without the implementation of a feedforward control loop based on trickling liquid velocity (TLV) and nitrate feeding rate manipulation for the aerobic and anoxic BTFs, respectively.RESULTSAn average LR of 80 g S‐H2S m–3 h–1 with peaks and valleys of 141 and 28 gS‐H2S m–3 h–1 were tested. At the highest H2S LR, a 68.4% and 62.6% reduction of maximum outlet H2S concentration, and 50.0% and 26.6% reduction of H2S cumulative mass emitted were reached in the aerobic and anoxic BTFs, respectively, thanks to the application of feedforward control strategies. The sulfate selectivity in the aerobic BTF was enhanced up to 100.6 ± 5.0% under controlled conditions. In the anoxic BTF the sulfate selectivity was kept constant at 32.8% ± 0.8%.CONCLUSIONDespite demonstrating that the feedforward controller significantly reduced the impact of disturbances, the utilization of TLV as manipulated variable in the aerobic reactor showed performance problems. However, the feedforward control through nitrate addition was shown to be an adequate, robust strategy for reducing the impact of load perturbation in anoxic BTFs. © 2018 Society of Chemical Industry

Acute and Chronic Management in an Atypical Case of Ethylmalonic Encephalopathy.

Ethylmalonic encephalopathy (EE) is caused by mutations in the ETHE1 gene. ETHE1 is vital for the catabolism of hydrogen sulfide (H2S). Patients with pathogenic mutations in ETHE1 have markedly increased thiosulfate, which is a reliable index of H2S levels. Accumulation of H2S is thought to cause the characteristic metabolic derangement found in EE. Recently introduced treatment strategies in EE, such as combined use of metronidazole (MNZ) and N-acetylcysteine (NAC), are aimed at lowering chronic H2S load. Experience with treatment strategies directed against acute episodes of metabolic decompensation (e.g., hemodialysis) is limited. Here we present an unusually mild, molecularly confirmed, case of EE in a 19-year-old male on chronic treatment with MNZ and NAC. During an acute episode of metabolic decompensation, we employed continuous renal replacement therapy (CRRT) to regain metabolic control. On continuous treatment with NAC and MNZ during the months preceding the acute event, plasma thiosulfate levels ranged from 1.6 to 4μg/mL (reference range up to 2μg/mL) and had a mean value of 2.5μg/mL. During the acute decompensation, thiosulfate levels were 6.7μg/mL, with hyperlactatemia and perturbed organic acid, acylglycine, and acylcarnitine profiles. CRRT decreased thiosulfate within 24h to 1.4μg/mL. Following discontinuation of CRRT, mean thiosulfate levels were 3.2μg/mL (range, 2.4-3.7μg/mL) accompanied by clinical improvement with metabolic stabilization of blood gas, acylcarnitine, organic acid, and acylglycine profiles. In conclusion, CRRT may help to regain metabolic control in patients with EE who have an acute metabolic decompensation on chronic treatment with NAC and MNZ.

Effect of hydrogen sulfide concentration in circulated amine solution on the treated gas in gas treatment plant

The concentration of dissolved hydrogen sulfide in circulated amine is necessary to be determined and calculated that useful to make a relationship with hydrogen sulfide in the treated gas after passing through the sweetening process in order to help to control the regeneration process when the research is containing the control system to improve the amine absorption capacity, regeneration efficiency and the concentration of H2S in treated gas for maintaining it under the specification value , Measurement of H2S in treated gas by GC-PFPD Shimadzu-2014 and determination of H2S loading by iodimetric titration in lean amine solution, the relationship between variables were satisfactory, means there is a directly proportional relationship between H2S in both Lean amine and Treated Gas according to increasing and decreasing.

Measuring and correlating solubility of hydrogen sulfide in aqueous solution of 2-((2 aminoethyl)amino)ethanol

The solubility of hydrogen sulfide (H2S) in aqueous solution of 2-((2-aminoethyl)amino)ethanol (AEEA) at low and medium pressures was determined for two different concentrations (i.e. 10 and 30 wt%). The experimental total pressure varied from (9.5 to 1594) kPa and the experimental temperature was set to (313.2, 328.2, 343.2 and 358.2) K. The experimental data are presented as the total pressure against acid gas loading (mole H2S per mole of AEEA). The Deshmukh-Mather model and Peng-Robinson equation of state were used for the liquid and vapour phase, respectively, to correlate the solubility of H2S in aqueous solutions of AEEA. The average absolute deviation percent (AAD%) in calculating the total pressure as a function of H2S loading obtained 5.0% for (AEEA– H2O–H2S) ternary system at the four values of temperature. The enthalpy change of the absorption of H2S in the 10 and 30 wt% aqueous solution of AEEA was also estimated with the tuned model.

Control of dissolved CH4 in a municipal UASB reactor effluent by means of a desorption – Biofiltration arrangement

The direct anaerobic treatment of municipal wastewater represents an adapted technology to the conditions of developing countries. In order to get an increased acceptance of this technology, a proper control of dissolved methane in the anaerobic effluents should be considered, as methane is a potent greenhouse gas. In this study, a pilot-scale system was operated for 168 days to recover dissolved methane from an effluent of an upflow anaerobic sludge blanket reactor and then oxidize it in a compost biofilter. The system operated at a constant air (0.9 m3/h ±0.09) and two air-to anaerobic effluent ratio (1:1 and 1:2). In both conditions (CH4 concentration of 2.7 ± 0.87 and 4.3% ± 1.14, respectively) the desorption column recovered 99% of the dissolved CH4 and approximately 30% ± 8.5 of H2S, whose desorption was limited due to the high pH (>8) of the effluent. The biofilter removed 70% ± 8 of the average CH4 load (60 gCH4/m3h ± 13) and 100% of the H2S load at an empty bed retention time of 23 min. The average temperature inside the biofilter was 42 ± 9 °C due to the CH4 oxidation reaction, indicating that temperature and moisture control is particularly important for CH4 removal in compost biofilters. The system may achieve a 54% reduction of greenhouse gas emissions from dissolved CH4 in this particular case.

Application of LS-SVM strategy to estimate H2S loading capacity in different ionic liquids and alkanolamines

ABSTRACTFavorable properties of aqueous solutions are improved with the addition of different materials for separation of hydrogen sulfide (H2S). Also, equilibrium data and available equations for solubility estimation of this gas are only valid for specific solutions and limited ranges of temperature and pressure. In this regard, a machine learning model based on Support vector machine (SVM) algorithm is proposed and developed with mixtures containing different amines and ionic liquids to predict H2S solubility over wide ranges of temperature (298–434.5 K), pressure (13–9319 kPa), overall mass concentration (3.82–100%) and mixture's apparent molecular weight (18.39–556.17 g/mol). The accuracy of the performance of this network was evaluated by regression analysis on calculated and experimental data, which had not been used in network training.

Delivery of Hydrogen Sulfide by Ultrasound Targeted Microbubble Destruction Attenuates Myocardial Ischemia-reperfusion Injury.

Hydrogen sulfide (H2S) is an attractive agent for myocardial ischemia-reperfusion injury, however, systemic delivery of H2S may cause unwanted side effects. Ultrasound targeted microbubble destruction has become a promising tool for organ specific delivery of bioactive substance. We hypothesized that delivery of H2S by ultrasound targeted microbubble destruction attenuates myocardial ischemia-reperfusion injury and could avoid unwanted side effects. We prepared microbubbles carrying hydrogen sulfide (hs-MB) with different H2S/C3F8 ratios (4/0, 3/1, 2/2, 1/3, 0/4) and determined the optimal ratio. Release of H2S triggered by ultrasound was investigated. The cardioprotective effect of ultrasound targeted hs-MB destruction was investigated in a rodent model of myocardial ischemia-reperfusion injury. The H2S/C3F8 ratio of 2/2 was found to be an optimal ratio to prepare stable hs-MB with higher H2S loading capability. Ultrasound targeted hs-MB destruction triggered H2S release and increased the concentration of H2S in the myocardium and lung. Ultrasound targeted hs-MB destruction limited myocardial infarct size, preserved left ventricular function and had no influence on haemodynamics and respiratory. This cardioprotective effect was associated with alleviation of apoptosis and oxidative stress. Delivery of H2S to the myocardium by ultrasound targeted hs-MB destruction attenuates myocardial ischemia-reperfusion injury and may avoid unwanted side effects.

Performance evaluation of a slow-release packing material-embedded functional microorganisms for biofiltration

ABSTRACTA composite packing material (CM-5) was prepared in this study, mainly consisting of compost with functional microorganisms, calcium carbonate (CaCO3), perlite, cement and plant fiber. To get stronger compressive strength, mass ratios of these components were optimized based on single factor experiments, and finally adding amounts of perlite, cement, plant fiber, CaCO3, compost and binder at 18%, 18%, 7%, 13%, 17% and 27%, respectively. According to the optimum proportion, CM-5 was extruded in cylindrical shape (12 mm in diameter and 20 mm in length) with a bulk density of 470 kg m−3, a moisture retention capacity of 49% and the microbial counts of × 105 CFU g−1 of packing material. The cumulative release rates of total organic carbon (TOC) and total nitrogen (TN) from CM-5 were 3.1% and 6.5%, respectively, after 19 times extraction in distilled water. To evaluate the H2S removal capacity, CM-5 was compared with an organic (corncob) and an inorganic (ceramsite) packing material in three biofilters. The results showed that CM-5 had higher H2S removal capacity compared with corncob and ceramsite. CM-5 could avoid the large fluctuation of pH value and pressure drop during the operation. The maximum H2S removal capacity of CM-5 was 12.9 g m−3 h−1 and the removal efficiency could maintain over 95.4% when the inlet H2S loading rate was lower than 11.3 g m−3 h−1 without any addition of nutrients and pH buffer substances. Besides, only 2–3 days were needed for the recovery of biofiltration performance after about two weeks of idle period.

Measuring solubility of hydrogen sulphide in aqueous blends of N-methyldiethanolamine and 2-((2 aminoethyl)amino)ethanol and correlating by the Deshmukh–Mather model

The solubility of hydrogen sulphide (H2S) in aqueous solution of N-methyldiethanolamine (MDEA) in the presence of different mole ratios of 2-((2-aminoethyl)amino)ethanol (AEEA) at low and medium pressures was obtained. The total concentrations of all the solutions have been fixed equal 3.36mol·L−1 (5.37 total moles of amines·kg−1 water). The mole ratio of [AEEA]/[MDEA] (mole ratio of AEEA per MDEA in fresh solutions) was set to 0.05, 0.10 and 0.125. The experimental total pressure varied from (7.3 to 1500) kPa and the temperatures were set to (313.2, 328.2, 343.2 and 358.2)K. The experimental values are presented as the total pressure against acid gas loading (mole H2S/total moles of amine). The results show that the AEEA concentration can improve absorption capacity of MDEA aqueous solution as the mole ratio [AEEA]/[MDEA] increases at constant total concentration. The Deshmukh–Mather model and Peng–Robinson equation of state were used for liquid and vapour phases, respectively to correlate the solubility of H2S in aqueous mixtures of AEEA and MDEA. The overall average absolute percent deviation (AAD%) in calculating the total pressure as a function of H2S loading obtained 8.15% for (AEEA–MDEA–H2S–H2O) quaternary system at the entire temperature and pressure ranges in this work.

Influence of MEA and piperazine additives on the desulfurization ability of MDEA aqueous for natural gas purification

The influence of monoethanolamine (MEA) and piperazine added into methyldiethanolamine (MDEA) aqueous solution on the desulfurization of natural gas was investigated by the method of equilibrium data determination in this paper. Four kinds of equilibrated systems, i.e. H2S-NG-MEA-water, H2S-NG-MDEA-water, H2S-NG-(MEA-MDEA)-water, H2S- NG-(MEA-MDEA-PZ)-water at the temperature ranging from 298.15 to 333.15 K were measured in a glass-jacketed gas absorption cell with a double-drive impeller device. The results show that the H2S partial pressure increases with the increase of H2S loading in liquid phase along an isotherm. The addition of MEA and PZ is beneficial for improving the desulfuration ability of MDEA. The ability of H2S absorption for the four mixed alkanolamine systems is MEA > (MEA-MDEA-PZ) > (MEA-MDEA) > MDEA according to the order of size. The four equilibrium data can be well correlated with the Soave–Redlich–Kwong equation of state and electrolyte-NRTL activity coefficient model. The overall mean relative errors of total pressure and H2S partial pressure between the calculated and experimental data of the four systems are 3.30 and 3.07 %, respectively. The experimental and calculated results are very useful for desulfuration and purification process of natural gas or other industrial gases.

Control of sulfide and methane production in anaerobic sewer systems by means of Downstream Nitrite Dosage

Bioproduction of hydrogen sulfide (H2S) and methane (CH4) under anaerobic conditions in sewer pipes causes detrimental effects on both sewer facilities and surrounding environment. Among the strategies used to mitigate the production of both compounds, the addition of nitrite (NO2−) has shown a greater long-term inhibitory effect compared with other oxidants such as nitrate or oxygen. The aim of this study was to determine the effectiveness of a new method, the Downstream Nitrite Dosage strategy (DNO2D), to control H2S and CH4 emissions in sewers. Treatment effectiveness was assessed on H2S and CH4 abatement on the effluent of a laboratory sewer pilot plant that mimics a full-scale anaerobic rising sewer. The experiment was divided in three different periods: system setup (period 1), nitrite addition (period 2) and system recovery (period 3). Different process and molecular methods were combined to investigate the impact of NO2− addition on H2S and CH4 production. Results showed that H2S load was reduced completely during nitrite addition when compared to period 1 due to H2S oxidation but increased immediately after nitrite addition stopped. The H2S overproduction during recovery period was associated with the bacterial reduction of different sulfur species (elemental sulfur/thiosulfate/sulfite) accumulated within the sewer biofilm matrix. Oxidation of CH4 was also detected during period 2 but, contrary to sulfide production, re-establishment of methanogenesis was not immediate after stopping nitrite dosing. The analysis of bulk and active microbial communities along experimental treatment showed compositional changes that agreed with the observed dynamics of chemical processes. Results of this study show that DNO2D strategy could significantly reduce H2S and CH4 emissions from sewers during the addition period but also suggest that microbial agents involved in such processes show a high resilience towards chemical stressors, thus favoring the re-establishment of H2S and CH4 production after stopping nitrite addition.

Prediction of acid gas solubility in amine, ionic liquid and amino acid salt solutions using artificial neural network and evaluating with new experimental measurements

In this work presented here attempt is prediction of acid gases (carbon dioxide and hydrogen sulfide) loading capacities by employing artificial neural network (ANN) model in 51 single and blended alkanolamine, ionic liquid and amino acid salt solutions as commonly and new industrial absorbents in large domain of operational conditions. Also for evaluating extrapolation capability of ANN, new experimental data on CO2 solubility in aqueous solutions of Potassium Glycinate blended with Piperazine (PZ) and 2-amino-2-methyl-1-propanol (AMP) at different temperatures and pressures are measured. It should be mention that CO2 solubility data for these two solutions are not available in literature. For developing ANN, solution pH, total mass concentration, partial pressure of CO2 and H2S, apparent molecular weight, critical temperature, critical pressure and temperature are assumed as inputs. A band of 2982 experimental data points for CO2 and H2S loading capacities have been collected from literature to create the suggested ANN. The best structure of the suggested network is achieved by employing these literature data points. The network is trained by algorithm of Levenberg–Marquardt back-propagation, consists of 9 and 6 neurons in first and second hidden layers, respectively. For the hidden and output layers, Tan-sigmoid transfer function is utilized. The output results of developed network show that suggested network that is created with solubility data of single and blended alkanolamine, ionic liquid and amino acid salt solutions has capability to predict accurately CO2 and H2S loading capacities in dissimilar commonly and new industrial solutions with Average Relative Deviation (ARD %) equal to 2.7992, Mean Square Error (MSE) value of 3.7468 × 10−5 and correlation coefficient (R2) equal to 0.9984.

Metagenomic analysis of a desulphurisation system used to treat biogas from vinasse methanisation

We investigated the response of microbial community to changes in H2S loading rate in a microaerated desulphurisation system treating biogas from vinasse methanisation. H2S removal efficiency was high, and both COD and DO seemed to be important parameters to biomass activity. DGGE analysis retrieved sequences of sulphide-oxidising bacteria (SOB), such as Thioalkalimicrobium sp. Deep sequencing analysis revealed that the microbial community was complex and remained constant throughout the experiment. Most sequences belonged to Firmicutes and Proteobacteria, and, to a lesser extent, Bacteroidetes, Chloroflexi, and Synergistetes. Despite the high sulphide removal efficiency, the abundance of the taxa of SOB was low, and was negatively affected by the high sulphide loading rate.