Adding organics to enrich mixotrophic sulfur-oxidizing bacteria under extremely acidic conditions—A novel strategy to enhance hydrogen sulfide removal
Graphical abstract
Introduction
Hydrogen sulfide (H2S) is an extremely hazardous gas with a rotten egg stench. It is a byproduct of many industrial processes, such as organic anaerobic digestion, petroleum refining, rendering, wastewater treatment, livestock farming, and food processing (Jia et al., 2022b; Qiu and Deshusses, 2017; Vikrant et al., 2018). H2S can damage various systems in the body, especially the nervous system, as well as corrode buildings and equipment. The H2S concentration in anaerobic digestion for producing biogas (mainly CH4, CO2, and H2S) can range from 1500 to 30,000 mg/m3 (Montebello et al., 2014; Vikrant et al., 2018). The most common H2S removal method is chemical washing (Pokorna et al., 2015), but this method is expensive. Burning H2S leads to the formation of sulfur dioxide, which causes acid rain. In contrast, biological desulfurization offers the advantages of being economic, efficient, and free of secondary pollution (Rybarczyk et al., 2019). However, the treatment of high load H2S, i.e., with a loading rate (LR) > 100 g-H2S/m3/h, is very challenging for biotrickling filter (BTF) since it has a constantly circulating liquid phase. Biotreatment of high load H2S results in rapid acidification of the bio-system because of the formation of sulfuric acid (de Rink et al., 2019). Extremely acidic conditions (pH < 1.0) eliminate non-aciduric sulfur-oxidizing bacteria (SOB) and are adverse to the growth of SOB biomass (Jia et al., 2022a). Such conditions make it difficult to further improve the desulfurization performance because of the lack of a sufficient amount of active SOB (Chen et al., 2021). Without enough SOB for the rapid oxidization of dissolved H2S, the accumulation of dissolved H2S (a highly toxic substrate) may inhibit or even kill SOB, thus causing the desulfurization system to collapse (Yuan et al., 2020). Continuous maintenance of the pH within a moderate range will significantly increase the operations complexity of high-load H2S treatment (Kim and Deshusses, 2005). In addition, moderate pH levels lead to an increase in microbial diversity (Montebello et al., 2013), which favors the growth of certain microorganisms not related to desulfurization. The current lack of methods to improve the H2S removal performance under extremely acidic conditions represents a critical constraint for the application of biotechnology for biogas desulfurization.
Commonly reported trophicity types of SOB are autotroph and heterotroph (Table S1). Heterotrophic SOB generally have a faster growth rate compared with autotrophic SOB, while most of they can only grow under neutral pH conditions (Haaijer et al., 2008; Kuddus et al., 2013; Nakayinga et al., 2021). Addition of organic carbon under neutral conditions with the goal to increase the biomass of heterotrophic SOB will inevitably lead to overgrowth by other heterotrophic microorganisms, thus resulting in a decrease in the H2S elimination capacity (EC) (Gao et al., 2011; Jin et al., 2007; Khanongnuch et al., 2019; Rene et al., 2009; Sologar et al., 2003). Mixotrophic SOB with a more flexible metabolic capacity can grow autotrophically on inorganic sulfides and can also grow heterotrophically on organic carbohydrate. Certain species of mixotrophic SOB can grow under extremely acidic conditions. For example, Alicyclobacillus disulfidooxidans can grow at pH levels ranging from 0.5 to 6.0 (Dufresne et al., 1996; Karavaiko et al., 2005). Moreover, the elution effect of extremely acidic conditions on non-aciduric microorganisms makes survival difficult for heterotrophic microorganisms (Montebello et al., 2013). Therefore, excessive proliferation of heterotrophic bacteria can be avoided under extremely acidic conditions even under the addition of organics.
Many studies have attempted to enhance the desulfurization performance by improving operating conditions (i.e., oxygen transfer, constant pH adjustments, or biofilm mass control) or inoculating purified SOB (Fernandez et al., 2014; Nguyen et al., 2016; Nisola et al., 2010; Rodriguez et al., 2014; Ryu et al., 2009; Tóth et al., 2015; Yang et al., 2010). Constantly maintaining optimal conditions requires more complex operations and tends to enable the growth of microorganisms not related to desulfurization. Inoculation with purified SOB is costly and not conducive to large-scale industrial applications. Several studies have investigated the performance of H2S removal under extreme acidic conditions, with low EC-H2S obtained (Ben Jaber et al., 2016; Jia et al., 2022a). Few studies have focused on enhancing the removal of H2S under extremely acidic conditions by adding organics to increase the biomass of mixotrophic SOB. Consequently, knowledge on the performance, microbial communities, and sulfur metabolism pathways of bio-desulfurization systems to which organics are added under extremely acidic conditions is insufficient.
The present study explored the strategy of increasing SOB biomass by adding an organic carbon source under extremely acidic conditions for advanced H2S removal. A biotrickling filter (BTF) under pH < 1.0 was established and operated under autotrophic conditions for 195 days and under mixotrophic conditions (i.e., adding an organic carbon source) for 277 days. The microbial community structure, biofilm mass, and maximum H2S elimination capacity (ECmax-H2S) were assessed in each period. The major metabolic pathways of sulfur in the desulfurization process were identified. Suitable external organic carbon sources were evaluated by exploring the organics degradation rate and SOB activity. The dosing strategy of organics and sulfur balance were analyzed to maintain biofilm mass balance and optimal desulfurization performance.
Section snippets
Reactor setup and operation procedure
The apparatus utilized in the experiment was a cylindrical reactor (diameter: 6 cm; height: 64 cm) (Fig. 1). Polyurethane foam (PUF) cubes, initial size of 1 × 1 × 1 cm, porosity of 94 % and specific surface area of 1000 m2/m3, were randomly stacked in the BTF with a packing height of 60 cm. There are mesh support plates at the height of 20 cm and 40 cm of the packing bed to avoid compression of the PUF cubes. H2S gas was produced by dripping Na2S solution into H2SO4 solution, and the formed H2
Desulfurization performance of the biotrickling filter system
Phase I was the autotrophic period without addition of external organic carbon. From day 1 to day 4, with an average Cin-H2S of 166.0 mg/m3, the RE-H2S rapidly increased from 47.8 % to almost 100 % (Fig. 2). However, the pH of the circulating liquid decreased from 6.8 to 6.1, indicating that the startup of the desulfurization system was successful. From day 5 to day 52 (phase I-1), the pH gradually switched from a normal range (pH > 2.0) to an extremely acidic range (pH < 1.0). This rapid
Conclusions
In this study, the BTF with addition of organics was studied under extremely acidic conditions, focusing on desulfurization performance, microbial community, and sulfur metabolism pathways. After the addition of glucose, the ECmax-H2S of BTF was increased by 272 % to 464.3 g/m3/h, with biofilm mass increasing from 10.8 to 22.3 g/L-BTF. The mixotrophic SOB Mycobacterium (78.4 %) and Alicyclobacillus (20.7 %) were enriched, while the autotrophic SOB Acidithiobacillus was gradually eliminated. The
CRediT authorship contribution statement
Tipei Jia: Conceptualization, Writing- Original draft preparation, Visualization
Liang Zhang: Writing- Reviewing and Editing, Funding acquisition
Shihao Sun: Resources, Validation
Qi Zhao: Methodology, Investigation
Yongzhen Peng: Visualization, Supervision, Writing- Reviewing and Editing
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgement
This work was supported by the Funding Projects of Beijing Municipal Commission of Education; Biological Wastewater Treatment and Process Control Technology, Beijing International Science and technology Cooperation Bas; and National Natural Science Foundation of China (52122005).
References (51)
- et al.
Biofiltration of high concentration of H2S in waste air under extreme acidic conditions
New Biotechnol.
(2016) - et al.
Removal of hydrogen sulfide by complete aerobic oxidation in acidic biofiltration
Process Biochem.
(2011) - et al.
Oxidation of hydrogen sulfide in biogas using dissolved oxygen in the extreme acidic biofiltration operation
Bioresour. Technol.
(2013) - et al.
Treatment of gaseous toluene in three biofilters inoculated with fungi/bacteria: microbial analysis, performance and starvation response
J. Hazard. Mater.
(2016) - et al.
Biogas biodesulfurization in an anoxic biotrickling filter packed with open-pore polyurethane foam
J. Hazard. Mater.
(2014) - et al.
Performance evaluation of packing materials in the removal of hydrogen sulphide in gas-phase biofilters: polyurethane foam, sugarcane bagasse, and coconut fibre
Chem. Eng. J.
(2010) - et al.
Simultaneous removal of hydrogen sulfide and toluene in a bioreactor: performance and characteristics of microbial community
J. Environ. Sci.
(2011) - et al.
Elimination of high concentration hydrogen sulfide and biogas purification by chemical-biological process
Chemosphere
(2013) - et al.
A robust 2D organic polysulfane nanosheet with grafted polycyclic sulfur for highly reversible and durable lithium-organosulfur batteries
Nano Energy
(2019) - et al.
Extremely acidic condition (pH< 1.0) as a novel strategy to achieve high-efficient hydrogen sulfide removal in biotrickling filter: biomass accumulation, sulfur oxidation pathway and microbial analysis
Chemosphere
(2022)
Co-treatment of hydrogen sulfide and methanol in a single-stage biotrickling filter under acidic conditions
Chemosphere
H2S removal and microbial community composition in an anoxic biotrickling filter under autotrophic and mixotrophic conditions
J. Hazard. Mater.
Understanding the limits of H2S degrading biotrickling filters using a differential biotrickling filter
Chem. Eng. J.
Production of laccase from newly isolated pseudomonas putida and its application in bioremediation of synthetic dyes and industrial effluents
Biocatal. Agric. Biotechnol.
Removal of hydrogen sulfide by sulfate-resistant Acidithiobacillus thiooxidans AZ11
J. Biosci. Bioeng.
Highly enriched anammox within anoxic biofilms by reducing suspended sludge biomass in a real-sewage A2/O process
Water Res.
Operational aspects, pH transition and microbial shifts of a H2S desulfurizing biotrickling filter with random packing material
Chemosphere
Aerobic desulfurization of biogas by acidic biotrickling filtration in a randomly packed reactor
J. Hazard. Mater.
Biosorption and biodegradation of a sulfur dye in high-strength dyeing wastewater by Acidithiobacillus thiooxidans
J. Environ. Manag.
Performance of a monolith biotrickling filter treating high concentrations of H2S from mimic biogas and elemental sulfur plugging control using pigging
Chemosphere
Biotrickling filters for biogas sweetening: oxygen transfer improvement for a reliable operation
Process Saf. Environ. Prot.
Treatment of malodorous air in biotrickling filters: a review
Biochem. Eng. J.
Thermophilic biofiltration of H2S and isolation of a thermophilic and heterotrophic H2S-degrading bacterium, Bacillus sp. TSO3
J. Hazard. Mater.
Degradation of hydrogen sulfide by immobilized thiobacillus thioparus in continuous biotrickling reactor fed with synthetic gas mixture
Int. Biodeterior. Biodegrad.
Biofiltration of hydrogen sulfide: trends and challenges
J. Clean. Prod.
Cited by (5)
Effect of nitrogen source and spray conditions on the integral biotrickling filter operation for hydrophobic volatile organic compounds
2023, Journal of Environmental Chemical Engineering