Biogenic Hydrogen Sulfide Research Articles

Increasing the efficiency of bactericide use when using seawater in a reservoir pressure maintenance system

Rationale: Since 2018, at the Uzen oilfield, in order to study and control the microbiological contamination with sulfate-reducing bacteria (hereinafter referred to as SRB) of oilfield environment, full-scale bactericidal treatment and monitoring of the effectiveness of reagent use have been carried out. At the equipped control points, water samples are taken for the content of SRB cells before and after injection of the bactericide.
 Target: Reduce the intensity of sulfidogenesis at the oilfield and, as a consequence, the concentration of hydrogen sulfide in the associated gas.
 Materials and methods: Since the applied technology of injecting the bactericide in shock dosages did not allow achieving a stable reduction in the concentration of hydrogen sulfide, it was replaced by the technology of constantly injecting the bactericide into seawater at a dosage of 40 mg/l in an experimental mode. This technology showed low efficiency, hydrogen sulfide (H2S) concentrations varied between 352–379 ppm, and the monthly consumption of the reagent increased by 40%. Based on the obtained data on ineffectiveness, the constant injection of bactericide at MPS-4 was stopped and a new technology for injection of bactericide was proposed, aimed at suppressing not only planktonic, but also adherent forms of SRB.
 Results: Results. Injection of the bactericide using the new technology showed significant efficiency, which was assessed by reducing the concentration of hydrogen sulfide in the associated gas by an average of 45% across the oilfield.
 Conclusion: The proposed new technology for injecting a bactericide made it possible to effectively suppress the activity of sulfidogenic microorganisms and reduce the level of biogenic hydrogen sulfide in the oilfield.

Soil concentrations and atmospheric emissions of biogenic hydrogen sulphide (H2S) in a Rhizophora mangrove forest

Mangrove forests are potentially large biogenic sources of atmospheric hydrogen sulphide (H2S), featuring among the carbon-richest ecosystems in the world associated with strong soil anoxia and large quantities of sulphates brought by tides. H2S is highly toxic and acts as a precursor for atmospheric sulphur compounds and sulphate aerosols, which contribute to acid deposition and have implications for global climate change. Therefore, understanding H2S emissions in mangroves holds great importance. Yet, its range of emissions remains uncertain. In this exploratory study, soil H2S concentrations were measured during tide stall at both high and low tide in a semi-arid mangrove, which has never been done before. Then, potential H2S fluxes to the atmosphere were estimated at low tide. Soil concentrations were greater at high tide than low tide, probably due to larger soil anoxia (average of −377 vs −179 mV), with average values of 1.40 ± 0.55 and 0.73 ± 0.32 mmol L−1, respectively. Temperature was a key factor controlling soil concentrations, with higher values in the warm season than in the cold season. Average H2S emissions ranged from 5.81 ± 2.58 to 28.74 ± 6.98 μg S m−2 h−1 with a mean value of 14.90 ± 7.90 μg S m−2 h−1. This study contributes to reducing the uncertainty in the variation range of H2S fluxes from mangroves, which may be significant for the global sulphur cycle.

Experimental and modeling investigations on the unexpected hydrogen sulfide rebound in a sewer receiving nitrate addition: Mechanism and solution

Biogenic hydrogen sulfide is an odorous, toxic and corrosive gas released from sewage in sewers. To control sulfide generation and emission, nitrate is extensively applied in sewer systems for decades. However, the unexpected sulfide rebound after nitrate addition is being questioned in recent studies. Possible reasons for the sulfide rebounds have been studied, but the mechanism is still unclear, so the countermeasure is not yet proposed. In this study, a lab-scale sewer system was developed for investigating the unexpected sulfide rebounds via the traditional strategy of nitrate addition during 195-days of operation. It was observed that the sulfide pollution was even severe in a sewer receiving nitrate addition. The mechanism for the sulfide rebound can be differentiated into short-term and long-term effects based on the dominant contribution. The accumulation of intermediate elemental sulfur in biofilm resulted in a rapid sulfide rebound via the high-rate sulfur reduction after the depletion of nitrate in a short period. The presence of nitrate in sewer promoted the microorganism proliferation in biofilm, increased the biofilm thickness, re-shaped the microbial community and enhanced biological denitrification and sulfur production, which further weakened the effect of nitrate on sulfide control during the long-term operation. An optimized biofilm-initiated sewer process model demonstrated that neither the intermittent nitrate addition nor the continuous nitrate addition was a sustainable strategy for the sulfide control. To minimize the negative impact from sulfide rebounds, a (bi)monthly routine maintenance (e.g., hydraulic flushing with nitrate spike) to remove the proliferative microorganism in biofilm is necessary.

Lytics broadcasting system: A novel approach to disseminate bacteriophages for disinfection and biogenic hydrogen sulphide removal tested in synthetic sewage

Owing to their selective nature, bacteriophages are prospective in targeted wastewater disinfection. Other potential applications include the removal of biogenic malodour and the mitigation of corrosion in sewerage pipelines. Nevertheless, its applications are ridden with challenges, the most prominent of which is scaling up. Towards that end, effective methodologies are required for dispersing phages into wastewater. The study describes a device arbitrarily named Lytics Broadcasting System. In principle, the device contains phages that can be continuously dispersed into wastewater. The modified version is called Bacteriophage Amplification Reactor, which operates with both phages and their respective hosts, ensuring continual production and dissemination of phages. Both prototypes utilize 0.22 μm cellulose membranes as an interface through which phage diffuse passively and selectively owing to its smaller size and established through membrane-overlay method. In the study, previously reported bacteriophage φPh_Se01 and Salmonella enterica were used. A reduction of 3–4 log was achieved with both the prototypes after 48 h of operation in 1 L of augmented synthetic sewage. Subsequently, the biogenic H2S produced by Salmonella enterica was reduced by 64–74% indicating its utility for targeted disinfection and malodour mitigation of wastewater. This study aims to provide a framework for the development of scalable prototypes of Lytic Broadcasting Systems for real-world wastewater applications.

Bacteriophage-based control of biogenic hydrogen sulphide produced by multidrug resistant Salmonella enterica in synthetic sewage

Sulphate-reducing bacteria (SRB) is widespread in sewers and wastewater treatment plants. They generate hydrogen sulphide (H2S) through anaerobic respiration using sulphur compounds as a terminal electron acceptor. H2S apart from causing undesired odour, is also responsible for corrosion in sewerage systems. Approaches in controlling odour and corrosion essentially involve the prevention of sulphide generation by SRBs. With that objective, bacteriophages were investigated for their potential in reducing H2S, using a multidrug resistant (MDR) Salmonella enterica clinical strain as a model SRB in simulated synthetic sewage settings. Two lytic phages specific to S. enterica were isolated from wastewater collected from the effluent treatment plant. The phages ϕPh_Se01 and ϕPh_Se02 possessed different plaque morphology and exhibited a distinct host range. Burst sizes of ϕPh_Se01 and ϕPh_Se02 were estimated to be 42 and 27 phages per infected cell respectively, with a latent period of 10 ± 5 min. Furthermore, nucleic acid analysis and melt curve profiles confirmed the diversity of these phages. Additionally, quantitative characterisation with regards to their stability in 10% (v/v) chloroform was used to comprehend their tolerance in large scale production. The study successfully demonstrated the application of ϕPh_Se01 and ϕPh_Se02 in the reduction of H2S by 62% and 70% respectively, within 6 h in synthetic sewage compared with the non-phage control. We also investigated the bacteriolytic ability of ϕPh_Se01 and ϕPh_Se02 in reducing the S. enterica by 4-log. This study demonstrates the potential of phage-mediated reduction of H2S and infection in wastewater.

Inhibition of biogenic hydrogen sulfide produce by Sulfate Reducing Bacteria isolated from oil fields in Basra by nitrate based treatment

The present study included using of Bio Competitive Exclusion BCX technology in treatment of biogenic production of hydrogen sulfide H2S by Sulfate Reducing Bacteria SRB in batch cultures, injection of nitrate and nitrite promotes the growth of Nitrate Reducing Bacteria NRB which outcompete the Sulfate Reducing Bacteria SRB on carbon sources. Mix cultures of SRB and NRB were isolated from produce water of oil production facilities in Iraq including Nahran Omer and Al lahis oil fields. The activity of NRB and SRB were determined by measured the concentration of nitrate, nitrite and sulfide by using spectrophotometer and bacterial counts in three tube MPN technique. The results showed that NRB had a certain inhibitory effect on the growth of SRB and sulfide production under adding NRB nutrient nitrate and nitrite at all concentrations 200, 400, 600, 800 and 1000 mg/l, activity of NRB increased after treatment, all nitrate and nitrite consumption during 2 - 3 days of incubation. The highest inhibition of H2S production was at concentration 1000 mg/l of nitrate where the results showed that there was significant decrease in sulfide level and number of bacteria 34 mg/l and 34.8 cell/ ml respectively after 10 days of treatment.

Condition Assessment for Concrete Sewer Pipes Using Displacement Probes: A Robotic Design Case Study

Worldwide, millions of kilometres of sewers are constructed from concrete pipes. Unfortunately, concrete sewers are susceptible to corrosion from biogenic hydrogen sulphide, and, though they may pass visual inspection, their ability to hold together under load may be degraded. This paper presents the design of a teleoperated robot with a protractible probe, that allows an operator to apply a localised load to selected points within a concrete sewer pipe. We report findings from laboratory and field trials of our prototype, with initial results suggesting that this approach has the potential to contribute useful information to sewer maintenance planning.

A pilot-scale sulfur-based sulfidogenic system for the treatment of Cu-laden electroplating wastewater using real domestic sewage as electron donor

Elemental sulfur (S0) reduction process has been demonstrated as an attractive and cost-efficient approach for metal-laden wastewater treatment in lab-scale studies. However, the system performance and stability have not been evaluated in pilot- or large-scale wastewater treatment. Especially, the sulfide production rate and microbial community structure may significantly vary from lab-scale system to pilot- or large-scale systems using real domestic sewage as carbon source, which brings questions to this novel technology. In this study, therefore, a pilot-scale sulfur-based sulfidogenic treatment system was newly developed and applied for the treatment of Cu-laden electroplating wastewaters using domestic sewage as carbon source. During the 175-d operation, >99.9% of Cu2+ (i.e., 5580 and 1187 mg Cu/L for two types of electroplating wastewaters) was efficiently removed by the biogenic hydrogen sulfide that produced through S0 reduction. Relatively high level of sulfide production (200 mg S/L) can be achieved by utilizing organics in raw domestic sewage, which was easily affected by the organic content and pH value of the domestic sewage. The long-term feeding of domestic sewage significantly re-shaped the microbial community in sulfur-reducing bioreactors. Compared to the reported lab-scale bioreactors, higher microbial community diversity was found in our pilot-scale bioreactors. The presence of hydrolytic, fermentative and sulfur-reducing bacteria was the critical factor for system stability. Accordingly, a two-step ecological interaction among fermentative and sulfur-reducing bacteria was newly proposed for sulfide production: biodegradable particulate organic carbon (BPOC) was firstly degraded to dissolved organic carbon (DOC) by the hydrolytic and fermentative bacteria. Then, sulfur-reducing bacteria utilized the total DOC (both DOC degraded from BPOC and the original DOC present in domestic sewage) as electron donor and reduced the S0 to sulfide. Afterwards, the sulfide precipitated Cu2+ in the post sedimentation tank. Compared with other reported technologies, the sulfur-based treatment system remarkable reduced the total chemical cost by 87.5‒99.6% for the same level of Cu2+ removal. Therefore, this pilot-scale study demonstrated that S0 reduction process can be a sustainable technology to generate sulfide for the co-treatment of Cu-laden electroplating wastewater and domestic sewage, achieving higher Cu2+removal and higher cost-effectiveness than the conventional technologies.

Study of bactericide properties of MARZA-1 agent in laboratory conditions

Bactericide properties of MARZA-1 inhibitor were studied with regard to desulfovibrio-desulfuricans and desulfo-microbium sulfate-reducing bacteria. According to the results of experiments, the effect of MARZA-1 inhibitor on the quantity of sulfate-reducing bacteria cells and formation of biogenic hydrogen-sulfide in Postgate-B nutritional medium has been estimated. MARZA-1 agent showed high bactericide effect towards desulfovibrio-desulfuricans and sulfate-reducing bacteria of desulfo-microbium type. The comparison of results with both bacteria justified that the rate of SRB cell disruption in the medium with desulfovibrio-desulfurican bacteria in the concentration of 7 mg/l on the fifth-seventh days, and in desulfo-microbium bacteria is observed with 10 mg/l concentration of MARZA-1 agent on the seventh day.

Universalism of inhibitors against hydrogen sulfide and carbon dioxide corrosion of carbon steel

The universality of inhibitors is understood as their ability to inhibit several types of corrosion attack: hydrogen sulfide and carbon dioxide corrosion, hydrogen diffusion into metal, development of sulfate-reducing and other types of bacteria, negative impact on the mechanical properties of metals. Indicators of universalism of new inhibitor have been studied. Producer of the inhibiting compositions is Limited Liability Company «INCORGAZ» (S-Petersburg, Russia). The efficacy of the inhibitor in the concentration of 25 - 200 mg/L has been studied with respect to carbon steel in a highly mineralized chloride medium (pH= 6) and NACE medium (5 g/L NaCl, 0.25 g/L CH3COOH, pH =3.5) containing H2S (50-400 mg/L) and CO2 (1at) separately and together. The bactericidal properties of the inhibitor were studied with respect to sulfate-reducing bacteria in the Postgate medium. The investigations were carried out by the methods of linear polarization resistance, electrochemical impedance spectroscopy, gravimetry, potentiodynamic polarization. The protective effectiveness of the inhibitor reaches 80% in the presence of CO2 and 90% in hydrogen sulphide environments. The inhibitor repeatedly reduces the number of sulfate-reducing bacteria and the production of biogenic hydrogen sulfide and inhibits the diffusion of hydrogen into steel.

The use of chiral anionic Co(III) complexes as inhibitors of corrosion and hydrogen absorption in water–salt media containing biogenic hydrogen sulfide

The use of chiral anionic Co(III) complexes as inhibitors of corrosion and hydrogen absorption in water–salt media containing biogenic hydrogen sulfide

Removal of heavy metals using a novel sulfidogenic AMD treatment system with sulfur reduction: Configuration, performance, critical parameters and economic analysis

A novel sulfidogenic acid mine drainage (AMD) treatment system with a sulfur reduction process was developed. During the 220-d operation, >99.9% of 380-mg/L ferric, 150-mg/L aluminum, 110-mg/L zinc, 20-mg/L copper and 2.5-mg/L lead ions, and 42.6–44.4% of 100-mg/L manganese ions in the synthetic AMD were step-by-step removed in the developed system with three pre-posed metal precipitators and a sulfur reduction reactor. Among them, zinc, copper and lead ions were removed by the biogenic hydrogen sulfide that produced through elemental sulfur reduction; while ferric, aluminum and manganese ions were removed by the alkali precipitation. Compared with the reported sulfate reduction reactors, the sulfur reduction reactor significantly reduced the chemical cost by 25.6–78.9% for sulfide production, and maintained a high sulfide production rate (1.12 g S2-/L-d). The pH level in the sulfidogenic reactor driven by sulfur-reducing bacteria posed a significant effect on the sulfide production rate. Under a nearly neutral condition (pH 7.0–7.5), elemental sulfur dissolved into polysulfide to increase the bioavailability of S0. At acidic conditions (pH < 6.0), polysulfide formation was limited and sulfate reduction became dominant. Therefore, maintaining the sulfidogenic reactor driven by sulfur-reducing bacteria at neutral condition is essential to realize high-rate and low-cost AMD treatment. Moreover, the escape of residual hydrogen sulfide from the system was eliminated by employing a 17% recirculation from effluent to the sulfidogenic reactor.

Biological Corrosion of Concrete

The article considers the results of studies to determine the causes, mechanisms and features of biological corrosion of cement concrete. It has been found that the intensive growth of microorganisms on the surface and in the pores of concrete leads to the formation of corrosive biogenic substances and, as a result, the reduction of alkalinity of cement stone with its subsequent decomposition. The influence of certain types of biogenic substances on the components of cement concrete (biogenic organic acids, biogenic carbon dioxide, biogenic nitric acid, biogenic hydrogen sulphide and sulfuric acid) is considered. Methods for increasing the biological resistance of concrete are described, such as: adding additives that can form buffer systems capable of reducing the impact on cement concretes of acids produced by microorganisms; treating the surface of composites with substances capable of repelling microorganisms and environments necessary for their vital activity; use of active media capable of forming dense and inert layers on the surface of the material. Despite the available methods of increasing the biological resistance of cement concrete, it is not possible to fully guarantee their safety from biocorrosion, at least because microorganisms can adapt to the environment and suspend the effect of protection. In this regard, the work attempts to assess and predict the biological resistance of the material.

Microbial iron reduction enhances in-situ control of biogenic hydrogen sulfide by FeOOH granules in sediments of polluted urban waters

This paper discusses the abiotic and biotic processes in the in-situ control of biogenic hydrogen sulfide generated from microbial sulfate reduction by ferric (FeIII) (hydr)oxides (FeOOH) granules in the sediments of polluted urban waters. Granular ferric hydroxide (GFH, β-FeOOH) and granular ferric oxide (GFO, α-FeOOH) dosed in the organic- and sulfate-rich sediments had 180% and 19% higher sulfide removal capacities than those used for the purely abiotic removal of dissolved sulfide, respectively. The enhancement was attributable to the involvement of the biotic pathways, besides the abiotic pathways (mainly sulfide oxidation). The FeOOH granules stimulated the microbial reduction of surface FeIII by iron-reducing bacteria (e.g., Desulfovibrio and Carnobacterium), and increased the microbial sulfate reduction by 24%–30% under an organic-rich condition, likely due to the enhanced organic fermentation. The microbial iron reduction significantly enhanced the removal of the formed biogenic hydrogen sulfide through increasing sulfide precipitation because it remarkably promoted the release of Fe2+ ions from the granule surface, likely due to the involvement of siderophores as ligands. This biotic pathway led to the formation of amorphous FeS(s) as a major sulfur product (56%–81%), instead of elemental sulfur. The enhancement in the sulfide control performance was much more pronounced when the poorly ordered GFH was used, because of the faster Fe2+ release, compared to the highly ordered GFO. The abiotic and biotic mechanisms elucidated in this study provide insights into the iron-sulfur chemistry in the sediments of various polluted waters (e.g., storm drains, urban rivers, and estuary), where the manually-dosed and naturally-occurring FeIII (hydr)oxides control biogenic hydrogen sulfide.

Recovery of Metals from Waste Lithium Ion Battery Leachates Using Biogenic Hydrogen Sulfide

Lithium ion battery (LIB) waste is increasing globally and contains an abundance of valuable metals that can be recovered for re-use. This study aimed to evaluate the recovery of metals from LIB waste leachate using hydrogen sulfide generated by a consortium of sulfate-reducing bacteria (SRB) in a lactate-fed fluidised bed reactor (FBR). The microbial community analysis showed Desulfovibrio as the most abundant genus in a dynamic and diverse bioreactor consortium. During periods of biogenic hydrogen sulfide production, the average dissolved sulfide concentration was 507 mg L−1 and the average volumetric sulfate reduction rate was 278 mg L−1 d−1. Over 99% precipitation efficiency was achieved for Al, Ni, Co, and Cu using biogenic sulfide and NaOH, accounting for 96% of the metal value contained in the LIB waste leachate. The purity indices of the precipitates were highest for Co, being above 0.7 for the precipitate at pH 10. However, the process was not selective for individual metals due to simultaneous precipitation and the complexity of the metal content of the LIB waste. Overall, the process facilitated the production of high value mixed metal precipitates, which could be purified further or used as feedstock for other processes, such as the production of steel.

Factors of effect on the corrosion destruction of metal of underground pipelines

A set of studies was conducted to determine the main factors influencing the corrosion destruction of metal in underground pipelines in two studied sections of the Pasichna-Tysmenitsa gaspipeline, covering definitions of active acidity, mass fraction of moisture, the presence of sulfate ions, and metal weight loss determined by the gravimetric method. It has been established that the pipeline in the studied sections of the route is laid in a soil of uniform acidity, which is low in pH acidic, which indicates corrosiveness of the soil in relation to steel. High soil moisture from the bottom of the pipeline in two sections of the route 18.21and 19.73 %, respectively, contributed to increased corrosion damage of the metal. Corrosion of the studied soils was carried out on the basis of certain metal weight loss. It was established that the soils on the studied sections of the route, the distance between which was about 1000 m, relate to soils with a high and normal degree of corrosivity. High corrosion activity is characteristic of the soil along the lower generatrix of the pipeline, which leads to an increase in the corrosion rate of the metal of underground pipelines in this zone. The intensification of corrosion processes in the soil adjacent to the pipeline, with an increase in metal exposure time in soil, has been established. The presence of sulfate ions in soil water extracts leads to the development of biocorrosion with the participation of sulfate-reducing bacteria, which indicated the formation of biogenic hydrogensulfide.

Hydrochemical Characteristics of the Aral Sea in 2012–2013

The decrease in Aral Sea area, which started in the 1960s, caused considerable changes in the hydrological, chemical, and biological structure of sea water. Regular observations of Aral water chemistry ceased in the early 1990s. There were no observations of the concentrations of biogenic element compounds in water (the so-called “first-day analyses”). During expeditions of the Institute of Oceanology, RAS, in September 2012 and October 2013, integrated hydrochemical observations were carried out, including measuring the concentrations of biogenic element compounds, dissolved oxygen, hydrogen sulfide, and carbonate equilibrium components. An objective of this study was to develop methods of hydrochemical studies under high water salinity (mineralization). In addition to the standard hydrochemical complex, water samples were taken to determine total water mineralization and the concentration of dissolved and suspended metal forms. The results of these studies are given.

Synthesis of Copper Sulfide Nanoparticles Using Biogenic H2S Produced by a Low-pH Sulfidogenic Bioreactor

The application of acidophilic sulfate-reducing bacteria (SRB) for the treatment of acidic mine water has been recently developed to integrate mine water remediation and selective biomineralization. The use of biogenic hydrogen sulfide (H2S) produced from the dissimilatory reduction of sulfate to fabricate valuable products such as metallic sulfide nanoparticles has potential applications in green chemistry. Here we report on the operation of a low-pH sulfidogenic bioreactor, inoculated with an anaerobic sediment obtained from an acid river in northern Chile, to recover copper via the production of copper sulfide nanoparticles using biogenic H2S. The laboratory-scale system was operated as a continuous flow mode for up to 100 days and the bioreactor pH was maintained by the automatic addition of a pH 2.2 influent liquor to compensate for protons consumed by biosulfidogenesis. The “clean” copper sulfide nanoparticles, produced in a two-step process using bacterially generated sulfide, were examined using transmission electron microscopy, dynamic light scattering, energy dispersive (X-ray) spectroscopy and UV-Vis spectroscopy. The results demonstrated a uniform nanoparticle size distribution with an average diameter of less than 50 nm. Overall, we demonstrated the production of biogenic H2S using a system designed for the treatment of acid mine water that holds potential for large-scale abiotic synthesis of copper sulfide nanoparticles.

Biological Production of Copper Sulfide Concentrate from Flotation Tailings and Low Grade Ore

Flotation tailings are hazardous due to physical and chemical instability and are currently considered one of the main pollution concerns of mining industry. Most of these tailings are fine-grained residues with low copper content (0.1-0.8%) and include toxic compounds, such as heavy metals, arsenic, and flotation reagents, among others. Another hazard is the generation of acid mine drainage (AMD) due to biological oxidation of tailings. On the other hand, low-grade ore is challenging the mining industry to commercially produce copper.The main objective of this work was to assess the use of flotation tailings and low-grade ore to produce a biologically-produced copper sulfide, as a product for further pyrometallurgical or fine chemistry processing. Low-grade ore and flotation tailings were first agglomerated at different proportions and leaching tests were performed in 1m columns, using either industrial or synthetic raffinate solution. Then, the PLS solution obtained from the column tests was subjected to selective precipitation of copper by using biogenic hydrogen sulfide (H2S) generated by a mixed culture of neutrophilic sulfate reducing bacteria (SRB), enriched from sediments of Caracarani river (located at 4,600 m over sea level in northern Chile).Over 91% of the copper soluble present in the PLS was recovered as copper sulfide in 28 days, while ferrous iron, other metals and arsenic remained in solution. Analysis performed by XRD confirmed the presence of copper in the precipitate (58% as covellite). This work demonstrates the possibility to apply bioleaching and bio-precipitation technologies to treat tailings and low-grade copper ore to produce a high quality copper sulfide.

Biogenic Hydrogen Sulfide for Cyanide Regeneration in Solutions during Cupriferous Gold Ores Processing

An optimal approach to the problem of cupriferous gold ores hydrometallurgical processing is the recycling of process solutions after copper recovery and regeneration of cyanide bound in complexes. The study focuses on the copper-cyanide solutions processing technology using biogenic hydrogen sulfide for copper recovery in the form of сhalcocite, and cyanide regeneration. The strains of anaerobic sulfidogenic thermophilic microorganisms Desulfurella acetivorans and Desulfurella Kamchatkensis were used for producing hydrogen sulfide. The studies on copper precipitation and cyanide regeneration were conducted on copper-cyanide process solutions which were obtained during cyanidation of refractory cupriferous gold-bearing flotation concentrates from one of the deposits in the South Ural (Russia). Ten cycles of "Cyanidation-Regeneration" were carried out in total. The copper recovery was 86–96 %; the cyanide regeneration obtained 96 %. On an average 8.9 kg of sodium cyanide and 4.6 kg of copper sulfide were recovered from 1 m3 of solution. The sodium cyanide consumption decreased from 25.0 kg/t to 6.0 kg/t without reducing gold recovery during the CIL (carbon-in-leach) recycling process. The gold recovery was the same 63–68 %.