What Affects the Efficiency of Ozone in Colour Removal Applications?

Colour removal in wastewater is one of the most pressing challenges for industries today. As discharge regulations become more stringent, conventional treatment methods often fall short of compliance standards. 

Ozone treatment has emerged as a reliable and eco-friendly solution for enhancing water quality. However, its efficiency is not uniform; it relies on several operational and environmental factors. Understanding these factors enables us to design industrial ozone generators that are effective and cost-efficient.

Factors Affecting the Efficiency of Ozone in Colour Removal Applications

At OTSIL, we’ve worked with many clients considering ozone for colour removal before effluent reuse or discharge. A common misconception is that ozone can be added at any point in the treatment process using a simple rule of thumb for dosing. In reality, the efficiency of ozone treatment is significantly influenced by site-specific conditions, the composition of the effluent, and the selected application strategy.

The following sections highlight the key factors that influence how effectively ozone works in colour removal applications.

Correct Location of Ozone Application

Ozone is most effective when used as a polishing agent rather than a stand-alone treatment. In wastewater treatment processes, it is generally applied after biological treatment to remove residual colour and enhance water quality. In many cases, combining ozone with biological treatment delivers the best results.

Effect of Turbidity 

High turbidity, caused by suspended solids, can cover colour-causing compounds from ozone and reduce treatment efficiency. Pre-treatment steps, such as coagulation and filtration, help lower turbidity, allowing ozone to act more effectively.

Effect of Organic Content 

Organic matter in water directly impacts the required ozone dosage. Higher COD levels demand a higher ozone dose for effective colour removal. Based on our experience, 200–250 ppm of COD is generally the upper limit for the economic viability of ozone in colour removal applications.

Type of Organic Targeted

Not all colour-causing compounds react the same way to ozone. While direct, reactive, mordant, sulphur, and cationic dyes can be effectively treated with ozone, disperse and VAT dyes are often resistant. It is essential to identify the type of compounds present before committing to ozone-based solutions.

Contact Time

The interaction time between ozone and effluent is essential. The optimal contact time varies based on the characteristics of the effluent, making pilot studies crucial for finding the best balance for maximum efficiency.

Effect of Ozone on TDS

In systems with separate high- and low-TDS discharge streams, improper ozone application can inadvertently increase TDS levels. Monitoring parameters beyond just colour during lab and pilot studies ensures balanced treatment.

Why Do Pilot Studies Matter?

Lab and pilot studies are crucial before investing in large-scale ozone systems for colour removal. From our experience, only 30–40% of cases prove economically viable for ozone-based treatment. 

OTSIL’s Role in Smarter Colour Removal

At OTSIL, we assist industries in making informed decisions through complementary lab studies and cost-effective pilot trials. These studies clarify the practicability, efficiency, and long-term costs, minimising the risks associated with large-scale implementation.

Take the first step towards smarter, sustainable wastewater treatment.

Connect with OTSIL’s experts or visit www.otsil.net to explore customised ozone solutions for your industry.