Removing sulphide from effluent water

Sulphide-containing effluent water is generated by a number of industries such as petrochemicals, automotive, oil and gas. Sulphide rich wastewater can have toxic effects on the environment and can emit an acidic, rotten-egg smell. This odour can become problematic, especially in residential areas and as such, companies may require a solution that can remove the excess hydrogen sulphide and reduce the emittance of bad odours.

When water in an effluent treatment system is allowed to sit for a prolonged period of time, it can become stagnant. Subsequently, the water starts to generate hydrogen sulphide as a by-product of biological activity. This is particularly problematic on small plants, which often do not have large effluent flows or a mechanical effluent treatment process, such as dissolved air flotation. In these situations, there is a risk that the periodic flow of liquid will pump water containing very high levels of hydrogen sulphide into the sewer system.

At Veolia Water Technologies UK (VWT UK), we offer a solution devised for this particular task. Our Hydrex 6935 chemical is a liquid product that can be added to the effluent stream Hydrex 6935 to neutralise any dissolved hydrogen sulphide. Attached to a square Intermediate Bulk Container (IBC), the 1000 litre solution regularly pumps small amounts of Hydrex 6935 into the effluent stream, breaking down bacteria and eradicating bad smells. The ‘plug and play’ system can be retrofitted onto an existing system and represents a low-tech, low-cost solution for firms owning and operating effluent treatment services.

With Hydrex 6935, clients are offered a reliable and robust hydrogen sulphide removal process. Prior to the solution, many factories used atomised aerosol sprays to mask bad smells on site, such as hydrogen sulphide. Unfortunately, these perfumes do little but alter the odour profile of the foul odour to something more palatable. Conversely, Hydrex 6935 actively breaks down the chemical, eliminating the foul odour and in turn, the issue.

Additionally, when left to generate over a prolonged period of time, hydrogen sulphide can become corrosive. In fact, even in low concentrations, hydrogen sulphide can begin to form weak acid, which is very corrosive. Within effluent treatment plant rooms, it is possible to create an environment in which hydrogen sulphide acid forms. This acid can corrode cold steel work and damage electrical cabinets and fixtures. Fortunately, by using Hydrex 6935, any gas that is generated is converted into a more inert compound, which can remain more safely in the water stream.

We have worked with a number of factories to install Hydrex 6935 and have received positive feedback from operators over its ability to eliminate airborne odour, as well as preventing the build-up of hydrogen sulphide acid.

For example, we were recently invited to an oil refinery to see if we could remove hydrogen sulphide from liquid waste. The liquid waste was created as a by-product of on-site operations and had become supersaturated in hydrogen sulphide gas. VWT UK’s team of experts carried out jar testing on samples of the liquid waste, which at the time contained hydrogen sulphide levels of above 5000 ppm. By using Hydrex 6935 in a fume cupboard, the team was able to reduce hydrogen sulphide levels down to an undetectable amount. By neutralising the chemical, the site was far more hospitable and posed less of a risk to engineers.

VWT UK’s innovative Hydrex 6935 offers customers a powerful effluent water treatment solution. The neutralising agent is able to break down hydrogen sulphide in stagnant water, eliminating bad smells and improving performance.

Once again, the new solution highlights that by working with a technical expert such as VWT UK, companies can conduct the proper support trials to ensure performance is guaranteed.

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Brian Jones

About the Author

Brian Jones

Brian has over 30 years experience in the chemical and water purification industry. The first 18 years were spent working for Hays Chemical Distribution in senior roles, working in quality, safety and process management. His problem solving approach and chemical background made going into wastewater treatment a good fit. He has spent the last 14 years working in sales in this industry having bought a wealth of knowledge to the role, proving to be a valuable asset.