A natural mineral to enhance the activated sludge process

Omya Optical is a natural calcium carbonate product for the enhancement and stabilization of activated sludge processes within municipal or industrial wastewater treatment.


© Omya 2021

Data Protection NoticeTerms & ConditionsImprintOMYA OPTICAL |

Technical Support

Omya's technical services team will help you implement the use of Omya Optical at your site. We offer advice on dosing requirements specific to your application and will work with you to identify potential operational improvements.

Book an appointment
Request a quote
Omya Optical has a natural buffering effect, unlike caustic soda, lime and, to a lesser extent, magnesium hydroxide, which risk harming the biology of the activated sludge through accidental overdosing. Excess Omya Optical extends the buffer against further acidification and maintains a stable operation. In contrast to lime and magnesium hydroxide, Omya Optical doesn’t clog pipes or leave hard deposits at the bottom or on the sides of tanks. This increases station availability and significantly reduces maintenance costs and man-hours.

Simplicity for Process Operations

Increased Safety

Omya Optical is a non-hazardous, non-corrosive product that is safer to handle and use than industry alternatives.
Read more

Operational Simplicity

The natural buffering properties of Omya Optical reduce the risk of overdosing and ensure a stable operation.
Read more

Enhanced Performance

Omya Optical provides the optimal environment for nitrifying bacteria, improving the biological performance of the activated sludge process.
Read more


Enhanced Biological Treatment Processes

Omya Optical provides a stable, optimal environment for nitrifying bacteria to improve efficiency and enhance operations.

Neutralizes Acidity & Stabilizes pH

The addition of Omya Optical substantially increases the carbonate alkalinity of the process, neutralizing any acidity and creating a perfectly buffered environment. This effect is long-lasting, ensuring stable operations.
Read more

Improves Flocculation

Omya Optical releases divalent ions, which bridge negatively charged sludge flocs to create larger, dense flocs. This improves settling, reduces the sludge volume index and leads to clearer effluent.
Read more

Treatment of Bulking Issues

The use of Omya Optical results in faster settling of bioflocs, reducing the sludge volume index for clearer effluent. Improved sedimentation reduces bulking issues caused by filamentous bacteria.
Read more

Better Dewatering

Denser flocs produced by Omya Optical improve sludge dewatering in decanter centrifuges and filter presses. This results in a smaller amount of dewatered sludge, reducing dewatering polymer consumption as well as sludge handling and disposal costs.
Read more

Equipment Supply

To support the implementation of Omya Optical at your site, Omya supplies storage and dosing equipment for both powders and slurries. These can be purchased outright or leased as part of a long-term package.
Request information



Omya Optical is available as powder or high solids liquid slurry. For large volumes, Omya Optical can be delivered by bulk transporter as either powder or slurry. For smaller volumes, slurry is supplied in IBC totes and powder in big bags or small sacks (25kg / 50lb bags).
Request a sampleCareers
ConstructionConsumer GoodsEnvironmental SolutionsPaper and BoardPolymers

Introducing Omya Optical

Omya Optical is a non-hazardous, non-corrosive product that is safe for handling and operations. This greatly reduces the risk profile for plant operators in comparison with caustic soda or lime. Safety training and procedures for spills and accidents are simpler and Omya Optical can be transported, handled and stored without special safety measures.

Increased Safety for Plant Operators

Request a sample
Omya Optical provides the ideal environment for nitrifying bacteria, which requires the pH to be in the range of 7-8 for full efficiency. Nitrification acidifies the activated sludge process, which slows the nitrification rate, increases levels of suspended solids and leads to concrete corrosion in basins and pipes. Omya Optical particles are integrated into the flocs and provide growth support to nitrifying bacteria and an alkalinity reservoir at the point of consumption.

Enhanced Biological Performance

Book a trial
The nitrification reaction produces acid as it consumes ammonium. This causes operational problems such as a slowing down of the nitrification process or floc decay which can lead to an increased level of suspended solids. The increased acidity results in concrete and steel corrosion in the pipes and basins. The dissolution of Omya Optical provides carbonate alkalinity to the process, ensuring a buffered and stable pH with a longer lasting effect over alternative solutions. Omya Optical particles are integrated into the flocs, providing an optimal environment for the nitrifying bacteria where it is needed: on a micro-level within the flocs themselves.

Neutralizes Acidity & Stabilizes pH

Maintaining the activated sludge and managing excess sludge are the most critical aspects of the activated sludge process. Omya Optical makes sludge control easier and more predictable for operators. The dissolution of Omya Optical releases divalent ions, which bridge negatively charged sludge flocs to create larger, denser flocs. Ultrafine flocs are then incorporated into this sludge matrix, which enables a simpler and more effective separation of the sludge blanket from the effluent. Undissolved Omya Optical particles are also incorporated into the floc structure, adding weight to the flocs.  This improves the quality of the effluent, and maintains the valuable biomass in the system which can be easily returned to the front of the plant via the Return-Activated-Sludge (RAS) line.

Improves Flocculation

The larger, denser flocs generated from application of Omya Optical improve the settling of the biomass, reducing the sludge volume index and leading to clearer effluent. Reduced turbidity and fewer ultrafine particles in the clarifier carry-over provide further benefits for downstream treatment processes, especially in the case of reuse applications. Improved sedimentation increases hydraulic capacity, and resolves bulking issues resulting from filamentous bacteria. This helps plants meet regulatory discharge allowances, protects the receiving water bodies and negates the need for additional capital investment in larger facilities.

Treatment of Bulking Issues Resulting from Filamentatous Bacteria

Omya Optical does not form precipitate accumulation at the bottom of basins or an increased amount of sludge, which can often happen when dosing lime. Denser flocs resulting from the application of Omya Optical improve the dewatering of sludge in decanter centrifuges and filter presses. This reduces the volume of dewatered sludge, lowering the consumption of polymer used for the dewatering and the handling and disposal costs of the sludge.

Better Dewatering and Less Sludge

ENVIRONMENTAL SOLUTIONS |Markets |Solutions |Library |Contact us