Wastewater managers embrace a new approach to pH management

Conventional pH management chemicals such as caustic soda, magnesium hydroxide and lime are essential in most wastewater treatment facilities for pH control and alkalinity addition. However, those chemicals can create challenges for operators. Hazardous, corrosive and often unstable, these commodities are also volatile in pricing, making economic operation increasingly difficult. A growing number of plant operators are looking for an alternative and finding it in a natural mineral.

“Plants are under pressure to treat increasing volumes of wastewater, often with aging infrastructure,” says Jarrod Massam, Director Market Development & Innovation for water at Omya Inc. “When you tell them that switching to Omya Optical can improve process efficiency, improve plant safety, and save money at the same time, they are all ears!”

Omya Optical is a natural solution for pH management made from natural calcium carbonate. It enhances the wastewater treatment system by creating a stable, pH neutral environment for the biological process as well as promoting floc formation and settling.

Eliminating pH swings

pH in wastewater treatment is traditionally managed using one of four options: caustic soda, hydrated lime, magnesium hydroxide or lime slurry. Apart from the price insecurity and potential supply chain risks, they each bring their own dosing and handling challenges. High fluctuations in pH are common, particularly with lime where the pH target is easy to overshoot, but also with caustic soda, where a very low contribution to alkalinity can lead to pH swings. Massam says plants don’t have this issue with Omya Optical: “The natural calcium carbonate of Omya Optical offers inherent buffering capacity, which provides a reservoir of alkalinity at the point of consumption, eliminating pH swings and protecting the biological treatment process.”

Improving safety and material handling

Massam reports that some plants are switching to non-hazardous products like Omya Optical because of growing concerns over operator safety and material handling challenges. “Caustic soda and lime are both hazardous materials and require proper PPE to ensure operator safety. Hydrated lime is especially difficult to handle, as it requires additional make-down equipment to produce a slurry before use, which is often a messy process. On top of this, plant operators have to contend with blockages and associated downtime caused by settling in the dosing lines. Magnesium hydroxide often results in similar struggles with dosing equipment as well as increasing the risk of struvite formation. With Omya Optical, they don’t need to worry about these issues. Even at higher concentrations, Omya Optical offers superior stability and does not promote scale formation in the wastewater treatment process.”

A cost-effective solution

An ongoing issue in water treatment is increasing chemical costs, exacerbated by volatile supply chains. This factor is such a concern that it has been added to the EPA Roadmap for a secure and resilient water and wastewater sector in the US. Caustic soda and magnesium hydroxide are the biggest culprits, but Massam claims that plants switching to Omya Optical are seeing significant savings, with one large plant halving their pH management bill by replacing magnesium hydroxide. “Alongside safety and handling, economic reasons continue to be the biggest driver for the switch.  The beauty of Omya Optical is that it provides benefits against traditional chemicals in all three key areas: safety, efficiency and cost.”