Dimethyl sulphide degradation using immobilized Thiobacillus thioparus in a biotrickling filter

Super enhancement of methanethiol biodegradation by new isolated Pseudomonas sp. coupling silicone particles

A new strain, Pseudomonas sp. SJ-1, which was able to remove model odorous organics methanethiol (MT) has been isolated from the wastewater treatment plant and identified via 16S rRNA analysis. Initial MT concentration, temperature and pH played an important role in MT removal, and up to 100% of 260 mg L^-1 of MT could be removed within 11 h under the optimum conditions (30 °C, pH 7.0) with an average degradation rate of 23.6 mg L^-1 h^-1, which was the highest one in literature so far. The silicone particles were added as the non-aqueous phases (NAP) to enhance the performance of MT degradation. The results indicated that the maximum degradation rate and specific cell growth of strain SJ-1 were 2.36 times and 1.31 times by Haldane kinetic model analysis in the NAP added test. The SO₄^2- was identified as the major intermediate and CO₂ as a final product in MT biodegradation. Overall, this is the first report that a newly isolated Pseudomonas sp. could use high concentration MT as sole energy source and carbon source and its activity could be enhanced by adding NAP. The results provide a suggestion for the development of more effective and reliable biological treatment processes.

Co-Treatment with Single and Ternary Mixture Gas of Dimethyl Sulfide, Propanethiol, and Toluene by a Macrokinetic Analysis in a Biotrickling Filter Seeded with Alcaligenes sp. SY1 and Pseudomonas Putida S1

The biotrickling filter (BTF) treatment is an effective way of dealing with air pollution caused by volatile organic compounds (VOCs). However, this approach is typically used for single VOCs treatment but not for the mixtures of VOC and volatile organic sulfur compounds (VOSCs), even if they are often encountered in industrial applications. Therefore, we investigated the performance of BTF for single and ternary mixture gas of dimethyl sulfide (DMS), propanethiol, and toluene, respectively. Results showed that the co-treatment enhanced the removal efficiency of toluene, but not of dimethyl sulfide or propanethiol. Maximum removal rates (rmax) of DMS, propanethiol and toluene were calculated to be 256.41 g·m−3·h−1, 204.08 g·m−3·h−1 and 90.91 g·m−3·h−1, respectively. For a gas mixture of these three constituents, rmax was measured to be 114.94 g·m−3·h−1, 104.17 g·m−3·h−1 and 99.01 g·m−3·h−1, separately. Illumina MiSeq sequencing analysis further indicated that Proteobacteria and Bacteroidetes were the major bacterial groups in BTF packing materials. A shift of bacterial community structure was observed during the biodegradation process.

Performance and microbial community dynamics relationship within a step-feed anoxic/oxic/anoxic/oxic process (SF-A/O/A/O) for coking wastewater treatment

A step-feed anoxic/oxic/anoxic/oxic (SF-A/O/A/O) was developed and successfully applied to full-scale coking wastewater treatment. The performance and microbial community were evaluated and systematically compared with the anoxic/oxic/oxic (A/O/O) process. SF-A/OA/O process exhibited efficient removal of COD, NH₄⁺-N, TN, phenols, and cyanide with corresponding average effluent concentrations of 317.9, 1.8, 46.2, 1.1, and 0.2 mg·L^-1, respectively. In particular, the TN removal efficiency of A/O/O process was only 7.8%, with an effluent concentration of 300.6 mg·L^-1. Furthermore, polycyclic aromatic hydrocarbons with high molecular weight were the dominant compounds in raw coking wastewater, which were degraded to a greater extent in SF-A/OA/O. The abundance in Thiobacillus, SM1A02, and Thauera could be the main reason why SF-A/O/A/O was superior to A/O/O in treating TN. The microbial community structure of SF-A/O/A/O was similar among stages in system (P ≥ 0.05, Welch's t-test) and was less affected by environmental factors, which may have been one of the important factors in the system's strong stability.

Biotrickling filter for the removal of volatile sulfur compounds from sewers: A review

Volatile sulfur compounds (VSCs) were identified as the dominant priority odorants emitted from sewers, including hydrogen sulfide (H₂S), methyl mercaptan (MM), dimethyl disulfide (DMDS) and dimethyl sulfide (DMS). Biotrickling filter (BTF) is a widely-applied technology for odour abatement in sewers because of its relatively low operating cost and efficient H₂S removal. The authors review the mechanisms and performance of BTF for the removal of these four VSCs, and discuss the key influencing factors including of empty bed residence time (EBRT), pH, temperature, nutrients, water content, trickling operation and packing materials. Besides, measures to improve the VSCs removal in BTF are proposed in the context of key influencing factors. Finally, the review assesses the new challenges of BTF for sewer emissions treatment, namely with respect to the performance of BTF for greenhouse gases (GHG) treatment.

The key role of Geobacter in regulating emissions and biogeochemical cycling of soil-derived greenhouse gases

In the past two decades, more and more attentions have been paid to soil-derived greenhouse gases (GHGs) including carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O) because there are signs that they have rising negative impacts on the sustainability of the earth surface system. Farmlands, particularly paddy soils, have been regarded as the most important emitter of GHGs (nearly 17%) due to a large influx of fertilization and the abundance in animals, plants and microorganisms. Geobacter, as an electroactive microorganism widely occurred in soil, has been well studied on electron transport mechanisms and the direct interspecies electron transfer. These studies on Geobacter illustrate that it has the ability to be involved in the pathways of soil GHG emissions through redox reactions under anaerobic conditions. In this review, production mechanisms of soil-derived GHGs and the amount of these GHGs produced had been first summarized. The cycling process of CH₄ and N₂O was described from the view of microorganisms and discussed the co-culture relationships between Geobacter and other microorganisms. Furthermore, the role of Geobacter in the production of soil-derived GHGs is defined by biogeochemical cycling. The complete view on the effect of Geobacter on the emission of soil-derived GHGs has been shed light on, and appeals further investigation.

Simultaneous methanethiol and dimethyl sulfide removal in a single-stage biotrickling filter packed with polyurethane foam: Performance, parameters and microbial community analysis

The bio-treatment of methanethiol (MT) and dimethyl sulfide (DMS), the most common sulfur compounds in odorous gas, is difficult due to the inhibition of DMS degradation by MT. This article investigated the treatment of MT and DMS odorous gas using a single-stage biotrickling filter (BTF) packed with polyurethane foam cubes that were inoculated with activated sludge from a sewage treatment plant operating an anaerobic/aerobic/oxic (AAO) process. The BTF system lasted for 161 days (with 9 days to startup) under an empty gas residence time of 39 s. The elimination capacities for MT and DMS were 85.2 g/m³/h (removal efficiency = 96.6%) and 6.4 g/m³/h (removal efficiency = 95.0%), respectively, and the maximal elimination capacities of MT and DMS were 119.7 g/m³/h and 7.3 g/m³/h, respectively. The optimal parameters were as follows: empty bed retention time, 39 s; pH, 6.1; recirculation medium flow rate, ≥1.2 m³/m²/h; temperature, 29-36 °C; and SO₄^2- concentration, < 2.0 g-SO₄^2-/L. Microbial community analysis revealed that spatial differentiation between MT-degrading bacteria and DMS-degrading bacteria enable the single-stage BTF can simultaneously remove MT and DMS. The activated sludge of AAO process can be used as the inoculation sludge to treating MT and DMS gas, which provides an important reference for the industrial application of treating odorous gas containing MT and DMS.

Operational parameters in H2S biofiltration under extreme acid conditions: performance, biomass control, and CO2 consumption

This paper reports the treatment of gaseous hydrogen sulfide, H₂S, in a biotrickling filter (BTF) under extreme acidic pH conditions (≈ 1.2). The effect of adding thiosulfate (Na₂S₂O₃.5H₂O) to promote biomass growth, feeding low concentrations of ozone to control excess biomass, and the carbon dioxide, CO₂, consumption by the chemolithoautotrophic consortium were evaluated. The results showed a global removal efficiency over 98.0% with loads of H₂S > 50 g m^-3 h^-1 (at 639 ppmv) and a linear relation between H₂S elimination capacity with the CO₂ consumption rate of around 0.1 gCO₂/gH₂S. Supplementing sulfur in the medium with 2 g L^-1 thiosulfate resulted in negative effect performance. Respirometry tests proved that the consortium could not utilize this sulfur form at this pH. Additionally, continuous and intermittent O₃ feeding to the BTF in gaseous concentrations of 98 ± 5.4 mg m^-3 caused a slight decreased in the performance but the biomass activity in the BTF was only slightly affected allowing a quick performance recovery once O₃ addition was suspended.

Structure and function of microbial community involved in a novel full-scale prefix oxic coking wastewater treatment O/H/O system

A novel full-scale prefix oxic coking wastewater (CWW) biological treatment O/H/O system had been operated steadily six years with the effluent quality meeting national discharge standard. Comparing to the traditional CWW biological treatment process, which usually have an anaerobic unit at the start of the process, here the O/H/O system has obvious advantages in COD removal, total nitrogen removal and reduced energy consumption. It is very necessary to illustrate the structure and function of the microbial community involved in different bioreactors of the O/H/O system. High-throughput MiSeq sequencing was used to examine the 16S rRNA genes in this system. Results revealed a contrasting microbial composition among the activated sludge samples of three sequential bioreactors: the β-Proteobacteria related sequences dominated in the O₁ activated sludge with the relative abundance of 56.44% while 7.53% of the sequences were assigned to Thiobacillus; Rhodoplanes related sequences dominated in the bioreactor H and O₂ activated sludge with relative abundance of 8.86% and 8.92%, respectively. The physico-chemical characteristics of CWW were analyzed by standard methods and the operational parameters were routinely monitored to examine their effects on the microbial communities. The bioinformatics software package of phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) was used to predict the microbial community functional profiling and found three dominant genera of Rhodoplanes, Lysobacter and Leucobacter enriched the xenobiotics biodegradation and metabolism pathway. The diverse and distinct microbial community involved in biological treatment processes of CWW treatment indicating that water characteristics and operational parameters determined the microbial community composition. These results significantly expanded our knowledge of the biodiversity and population dynamics of microorganisms and discerned the relationships between bacterial communities and environmental variables in the biological treatment processes. Moreover, in this study, we proposed a comprehensive biodegradation model of CWW treatment and defined as O/H/O system.

Structure and function of microbial community associated with phenol co-substrate in degradation of benzo[a]pyrene in coking wastewater

Coking wastewater (CWW) contains high contents of phenols and other toxic and refractory compounds including polycyclic aromatic hydrocarbons (PAHs) with the most carcinogenic benzo[a]pyrene (BaP) among them. The mechanism of PAHs/BaP degradation in activated sludge of CWW treatment with phenol as co-substrate was studied. For characterizing the structure and functions of microbial community associated with BaP degradation with phenol as co-substrate, high-throughput MiSeq sequencing was used to examine the 16S rRNA genes of microbiology, revealing noticeable shifts in CWW activated sludge bacterial populations. Major genera involved in anaerobic degradation were Tissierella_Soehngenia, Diaphorobacter and Geobacter, whereas in aerobic degradation Rhodanobacter, Dyella and Thauera prevailed. BaP degradation with phenol as co-substrate induced bacterial diversification in CWW activated sludge in opposite trends when anaerobic and aerobic conditions were applied. In order to predict the microbial community functional profiling, a bioinformatics software package of phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) was run to find that some dominant genera enriched in the BaP pathway may own the ability to degrade PAHs/BaP. Further experiments should focus on testing the dominant genera in BaP degradation at different oxygen levels.

Enhancement of using combined packing materials on the removal of mixed sulfur compounds in a biotrickling filter and analysis of microbial communities

Background

Packing materials is a critical design consideration when employing biological reactor to treat malodorous gases. The acidification of packing bed usually results in a significant drop in the removal efficiency. In the present study, a biotrickling filter (BTF2) packed with plastic balls in the upper layer and with lava rocks in the bottom layer, was proposed to mitigate the acidification.

Results

Results showed that using combined packing materials efficiently enhanced the removal performance of BTF2 when compared with BTF1, which was packed with sole lava rocks. Removal efficiencies of more than 92.5% on four sulfur compounds were achieved in BTF2. Average pH value in its bottom packing bed was about 4.86, significantly higher than that in BTF1 (2.85). Sulfate and elemental sulfur were observed to accumulate more in BTF1 than in BTF2. Analysis of principal coordinate analysis proved that structure of microbial communities in BTF2 changed less after the shutdown but more when the initial pH value was set at 5.5. Network analysis of significant co-occurrence patterns based on the correlations between microbial taxa revealed that BTF2 harbored more diverse microorganisms involving in the bio-oxidation of sulfur compounds and had more complex interactions between microbial species.

Conclusions

Results confirmed that using combined packing materials effectively improved conditions for the growth of microorganisms. The robustness of reactor against acidification, adverse temperature and gas supply shutdown was greatly enhanced. These provided a theoretical basis for using mixed packing materials to improve removal performance.

Methane production from a field-scale biofilter designed for desulfurization of biogas stream

The development of a simple and low maintenance field-scale biotrickling filter (BTF) for desulfurization of swine wastewater-derived biogas stream that was also capable of increasing biomethane concentrations was investigated. BTF was continuously fed with wastewater effluent from an air sparged nitrification-denitrification bioreactor installed downgradient from an UASB-type digester. BTF maximum removal efficiency (RE) of 99.8% was achieved with a maximum elimination capacity (EC) of 1,509 g H2S m(-3) h(-1). Average EC obtained with inlet biogas flow rates of 0.024, 0.036 and 0.048 m(3) h(-1) was 718, 1,013 and 438 g H2S m(-3) h(-1), respectively. SO4(-2) and S(0) were the major metabolites produced from biological conversion of H2S. Additionally to the satisfactory biodesulfurization capacity, an average increase in methane concentration of ≅ 3.8 ± 1.68 g m(-3) was measured in the filtered gas stream throughout 200 days of BTF operation. RT-PCR analyses of archaea communities in the biofilm confirmed dominance of hydrogenotrophic methanogens thus corroborating with the observed strong correlation between CO2 removal and CH4 production. Among the three major archaea orders investigated (i.e., Methanosarcinales, Methanobacteriales, and Methanomicrobiales), Methanobacteriales were encountered at highest concentrations (1.9 × 10(11) gene copies mL(-1)). The proposed BTF was robust efficiently removing H2S from biogas stream while concomitantly enhancing the concentration of valuable methane as source of renewable fuel.

Efficient bio-deodorization of thioanisole by a novel bacterium Brevibacillus borstelensis GIGAN1 immobilized onto different parking materials in twin biotrickling filter

Biological treatment of odorous gas is an alternative to conventional physicochemical processes. A newly-isolated and identified Brevibacillus borstelensis GIGAN1 was seeded on active carbon (AC) and ceramic particle (CP) in a twin biotrickling filter (BTF) to comparatively probe the removal performance of gaseous thioanisole, respectively. At empty bed residence time (EBRT) of 66 s, 100% of thioanisole (⩽ 3mg L(-1)) could be removed on AC; while 100% of thioanisole could only be achieved for ⩽ 1.2 mg L(-1) on CP. Further increase thioanisole concentration to 3 mg L(-1), higher elimination capacity was obtained on AC (162.51 g m(-3)h(-1)) than CP (139.93 g m(-3)h(-1)). Further, longer EBRT was also beneficial to thioanisole removal. Additionally, the biomass accumulation did not lead to the column clogging. The bio-deodorization mechanism of thioanisloe were also tentatively proposed. Overall, an unprecedented performance could be achieved by the novel GIGAN1 in BTF for thioanisole biodegradation.

Potentialities of coupling biological processes (biotrickler/biofilter) for the degradation of a mixture of sulphur compounds

This study deals with the potential of biological processes combining a biotrickler and a biofilter to treat a mixture of sulphur-reduced compounds including dimethyl sulphide (DMS), dimethyl disulphide (DMDS) and hydrogen sulphide (H2S). As a reference, duplicated biofilters were implemented, and operating conditions were similar for all bioprocesses. The first step of this work was to determine the efficiency removal level achieved for each compound of the mixture and in a second step, to assess the longitudinal distribution of biodegradation activities and evaluate the total bacteria, Hyphomicrobium sp. and Thiobacillus thioparus densities along the bed height. A complete removal of hydrogen sulphide is reached at the start of the experiment within the first stage (biotrickler) of the coupling. This study highlighted that the coupling of a biotrickling filter and a biofilter is an interesting way to improve both removal efficiency levels (15-20% more) and kinetics of recalcitrant sulphur compounds such as DMS and DMDS. The total cell densities remained similar (around 1 × 10(10) 16S recombinant DNA (rDNA) copies g dry packing material) for duplicated biofilters and the biofilter below the biotrickling filter. The relative abundances of Hyphomicrobium sp. and T. thioparus have been estimated to an average of 10 ± 7.0 and 0.23 ± 0.07%, respectively, for all biofilters. Further investigation should allow achieving complete removal of DMS by starting the organic sulphur compound degradation within the first stage and surveying microbial community structure colonizing this complex system.

Linking TFT-LCD wastewater treatment performance to microbial population abundance of Hyphomicrobium and Thiobacillus spp

This study investigated the linkage between performance of two full-scale membrane bioreactor (MBR) systems treating thin-film transistor liquid crystal display (TFT-LCD) wastewater and the population dynamics of dimethylsulfoxide (DMSO)/dimethylsulfide (DMS) degrading bacteria. High DMSO degradation efficiencies were achieved in both MBRs, while the levels of nitrification inhibition due to DMS production from DMSO degradation were different in the two MBRs. The results of real-time PCR targeting on DMSO/DMS degrading populations, including Hyphomicrobium and Thiobacillus spp., indicated that a higher DMSO oxidation efficiency occurred at a higher Hyphomicrobium spp. abundance in the systems, suggesting that Hyphomicrobium spp. may be more important for complete DMSO oxidation to sulfate compared with Thiobacillus spp. Furthermore, Thiobacillus spp. was more abundant during poor nitrification, while Hyphomicrobium spp. was more abundant during good nitrification. It is suggested that microbial population of DMSO/DMS degrading bacteria is closely linking to both DMSO/DMS degradation efficiency and nitrification performance.

A comparative study of two composts as filter media for the removal of gaseous reduced sulfur compounds (RSCs) by biofiltration: application at industrial scale

This work presents the use of two composts as filter media for the treatment by biofiltration of odors emitted during the aerobic composting of a mixture containing sewage sludge and yard waste. The chemical analysis of the waste gas showed that the malodorous compounds at trace level were the reduced sulfur compounds (RSCs) which were dimethyl sulfide (Me(2)S), methanethiol (MeSH) and hydrogen sulfide (H(2)S). Laboratory tests for biofiltration treatment of RSCs were performed in order to compare the properties of two filter media, consisted of a mature compost with yard waste (YW) and a mixture of mature compost with sewage sludge and yard waste (SS/YW). The maximum elimination capacity (EC) values obtained with the YW mature compost as packing material were 12.5 mg m(-3)h(-1) for H(2)S, 7.9 mg m(-3)h(-1) for MeSH and 34 mg m(-3)h(-1) for Me(2)S, and the removal efficiency decreased in the order of: H(2)S>MeSH>Me(2)S. Moreover, the YW compost filter medium had a better behavior than the filter medium based on SS/YW in terms of acclimation of the microbial communities and moisture content. According to these results, a YW mature compost as packing material for an industrial biofilter were designed and this industrial biofilter was found effective under specified conditions (without inoculation and addition of water). The results showed that the maximum EC value of RSCs was 935 mg m(-3)h(-1) (100% removal efficiency, RE) for an inlet loads (IL) between 0 and 1000 mg m(-3)h(-1). Thus, YW compost medium was proven efficient for biofiltration of RSCs both at laboratory and industrial scale.

Dimethyl sulfide biofiltration using immobilized Hyphomicrobium VS and Thiobacillus thioparus TK-m in sugarcane bagasse

Sugarcane bagasse was used as a carrier material of microorganisms in two different biofilters used to remove dimethyl sulfide (DMS) from a gas stream. The first biofilter was inoculated with Hyphomicrobium VS and the second with Thiobacillus thioparus Tk-m. During the operation of the biofilters the empty bed residence time (EBRT) was varied from 90 to 180 seconds and the inlet concentration of DMS from 12 to 50 ppmv. The inlet load was varied in the range of 0.62 to 5.2 (g DMS/m3 h). The maximum elimination capacity (EC) of the biofilter inoculated with Hyphomicrobium VS was 5 g DMS/m3 h; however, for the biofilter inoculated with T. thioparus Tk-m the maximum EC was 3.9 g DMS/m3 h. For T. thioparus TK-m the maximum removal efficiency (RE) obtained was 85.1 +/- 5.2% at 12 ppmv DMS inlet concentration, inlet load of 0.62 g DMS/m3 h and 180 s EBRT. The highest removal efficiency for Hyphomicrobium VS was 97.6 + 4.8% at 12 ppmv DMS inlet concentration, load of 0.62 g DMS/m3 h and 180 s EBRT.

Composition and dynamics of microbial community in a zeolite biofilter-membrane bioreactor treating coking wastewater

In this study, a lab-scale anaerobic/anoxic/zeolite biofilter-membrane bioreactor (A1/A2/ZB-MBR) was designed to treat coking wastewater. The 454 pyrosequencing was used to obtain the composition and dynamics of microbial community about the treatment system. The results showed that the system yielded stable effluent chemical oxidation demand (158.5 ± 21.8 mg/L) and ammonia (8.56 ± 7.30 mg/L), but fluctuant total nitrogen (31.4-165.1 mg/L) concentrations. In addition, 66,256 16S rRNA gene sequences were obtained from A2 and ZB-MBR, and the microbial diversity and richness for five samples were determined. Although community compositions in the five samples were quite different, bacteria assigned to phylum Proteobacteria and class Flavobacteria commonly existed and dominated the microbial populations. The pyrosequencing analysis revealed that the microbial community shifted in the ZB-MBR with the presence of zeolite. Some taxa began to appear in ZB-MBR and contributed to the system performance. Additionally, Nitrosomonas and Nitrobacter gradually became the dominant ammonia-oxidizing bacteria and nitrite-oxidizing bacteria during the operation, respectively, which are favorable for the stabilized ammonia removal. Our results proved that the ZB-MBR is an alternative technique for treating coking wastewater.

Biofiltration of reduced sulphur compounds and community analysis of sulphur-oxidizing bacteria

The present work aims to use a two-stage biotrickling filters for simultaneous treatment of hydrogen sulphide (H(2)S), methyl mercaptan (MM), dimethyl sulphide (DMS) and dimethyl disulphide (DMDS). The first biofilter was inoculated with Acidithiobacillus thiooxidans (BAT) and the second one with Thiobacillus thioparus (BTT). For separate feeds of reduced sulphur compounds (RSC), the elimination capacity (EC) order was DMDS>DMS>MM. The EC values were 9.8 g(MM-S)/m(3)/h (BTT; 78% removal efficiency (RE); empty bed residence time (EBRT) 58 s), 36 g(DMDS-S)/m(3)/h (BTT; 94.4% RE; EBRT 76 s) and 57.5 g(H2S-S)/m(3)/h (BAT; 92% RE; EBRT 59 s). For the simultaneous removal of RSC in BTT, an increase in the H(2)S concentration from 23 to 293 ppmv (EBRT of 59 s) inhibited the RE of DMS (97-84% RE), DMDS (86-76% RE) and MM (83-67% RE). In the two-stage biofiltration, the RE did not decrease on increasing the H(2)S concentration from 75 to 432 ppmv.