A method for treating sulfide in an aqueous fluid comprises contacting the fluid with an oxidizer in the presence of a sulfur dye or sulfurized vat dye. In one embodiment, the method comprises treating sulfide contaminated water by contacting the contaminated water with a gas including oxygen in the presence of a sulfur dye or a sulfurized vat dye. The method is useful for remediating industrial, agricultural, and municipal wastewater.

A method for removing hydrogen sulfide from a biogas, wherein the hydrogen sulfide is absorbed in an aqueous liquid to produce a cleaned gas having a reduced amount of hydrogen sulfide relative to the biogas. The aqueous liquid is subsequently treated by contacting with a sulfur dye or sulfurized vat dye in the presence of an oxidizer such as oxygen gas, to convert the sulfides in the aqueous liquid to a non-toxic, water-soluble, product.

A method for removing hydrogen sulfide from a biogas, wherein the hydrogen sulfide is absorbed in an aqueous liquid to produce a cleaned gas having a reduced amount of hydrogen sulfide relative to the biogas. The aqueous liquid is subsequently treated by contacting with a sulfur dye or sulfurized vat dye in the presence of an oxidizer such as oxygen gas, to convert the sulfides in the aqueous liquid to a non-toxic, water-soluble, product.

The invention is directed to a control method for a process to convert bisulphide to elemental sulphur in an aqueous solution comprising sulphide-oxidising bacteria wherein the process is controlled by applying a potential between the anode electrode and the cathode electrode or between the anode electrode and the reference electrode of an electrochemical cell resulting in a current between the cathode electrode and the anode electrode, measuring a current as measured by an electrochemical cell and adapting the process in response to the measured current. The process to convert bisulphide may comprise the following steps: (a) contacting bisulphide with oxidised sulphide-oxidising bacteria in the aqueous solution and elemental sulphur, (b) oxidizing the reduced sulphide-oxidising bacteria, (c) using the oxidised sulphide-oxidising bacteria obtained in step (b) in step (a) and (d) isolating elemental sulphur from the aqueous solution obtained in step (a) and/or step (b).

The invention is directed to a control method for a process to convert bisulphide to elemental sulphur in an aqueous solution comprising sulphide-oxidising bacteria wherein the process is controlled by applying a potential between the anode electrode and the cathode electrode or between the anode electrode and the reference electrode of an electrochemical cell resulting in a current between the cathode electrode and the anode electrode, measuring a current as measured by an electrochemical cell and adapting the process in response to the measured current. The process to convert bisulphide may comprise the following steps: (a) contacting bisulphide with oxidised sulphide-oxidising bacteria in the aqueous solution and elemental sulphur, (b) oxidizing the reduced sulphide-oxidising bacteria, (c) using the oxidised sulphide-oxidising bacteria obtained in step (b) in step (a) and (d) isolating elemental sulphur from the aqueous solution obtained in step (a) and/or step (b).

The invention is directed to a process to prepare elemental sulphur by (i) contacting an aqueous solution comprising bisulphide with oxidised sulphide-oxidising bacteria under anaerobic conditions wherein elemental sulphur is produced and a reduced sulphide-oxidising bacteria is obtained and (ii) wherein the reduced sulphide-oxidising bacteria are oxidised by transfer of electrons to an anode of an electrochemical cell to obtain the oxidised sulphide-oxidising bacteria.

Embodiments of the disclosure include systems and processes for the recovery of sulfur dioxide (SO.sub.2) from tail gas of sulfur recovery plant or from flue gas of a power plant, such as flue gas originating from an H.sub.2S-containing fuel gas for a gas turbine. SO.sub.2-containing gas is dissolved in chilled water and produce SO.sub.2-containing chilled water. The SO.sub.2-containing chilled is contacted with H.sub.2S-containing gas to aqueously react H.sub.2S and SO.sub.2 and form elemental sulfur. A water stream with the entrained sulfur is routed to a solid-liquid separate, and separated sulfur may be processed or disposed of. The water is recycled and chilled for use in the reaction. Embodiments also include the generation of sulfur dioxide (SO.sub.2) from produced sulfur instead of using tail gas or flue gas.

Embodiments of the disclosure include systems and processes for the recovery of sulfur dioxide (SO.sub.2) from tail gas of sulfur recovery plant or from flue gas of a power plant, such as flue gas originating from an H.sub.2S-containing fuel gas for a gas turbine. SO.sub.2-containing gas is dissolved in chilled water and produce SO.sub.2-containing chilled water. The SO.sub.2-containing chilled is contacted with H.sub.2S-containing gas to aqueously react H.sub.2S and SO.sub.2 and form elemental sulfur. A water stream with the entrained sulfur is routed to a solid-liquid separate, and separated sulfur may be processed or disposed of. The water is recycled and chilled for use in the reaction. Embodiments also include the generation of sulfur dioxide (SO.sub.2) from produced sulfur instead of using tail gas or flue gas.

A method for treating sulfide in an aqueous fluid comprises contacting the fluid with an oxidizer in the presence of a sulfur dye or sulfurized vat dye. In one embodiment, the method comprises treating sulfide contaminated water by contacting the contaminated water with a gas including oxygen in the presence of a sulfur dye or a sulfurized vat dye. The method is useful for remediating industrial, agricultural, and municipal wastewater.

A method for treating sulfide in an aqueous fluid comprises contacting the fluid with an oxidizer in the presence of a sulfur dye or sulfurized vat dye. In one embodiment, the method comprises treating sulfide contaminated water by contacting the contaminated water with a gas including oxygen in the presence of a sulfur dye or a sulfurized vat dye. The method is useful for remediating industrial, agricultural, and municipal wastewater.