Textile wastewater streams, as well as industrial waste streams, have been successfully treated with ozone throughout the world. A combination of ozone and biological treatment systems, such as activated sludge, is often used to treat wastewater. Because of their large molecular sizes, organic dyes are generally refractory and cannot be rapidly removed by adsorption on activated sludge. In some cases, ozone is used before biological treatment.  Ozone dye color removal is excellent option for any industry involved in textile processing.

Ozone in Wastewater and Textile Processing

The use of ozone is gradually replacing chlorine in wastewater and textile processing. The oxidizing power of ozone makes it safer to use than other oxidizing agents. When dissolved materials absorb visible light, or when light is reflected from suspended solids, water appears colored. 

As ozone has a tendency to break organic molecules down into smaller, more biodegradable species, it can be used before a biological process. In turn, the process will be more efficient. A second advantage of ozone treatment is the increase in oxygen content of wastewater (mixed with water unconverted oxygen and decomposing ozone) resulting in improved aerobic processes. There is a lot of literature about this benefit, but it is difficult to apply it practically since the improvement amount is difficult to predict and pilot studies involving biological processes and ozone are difficult to conduct. The ozone treatment have been found to improve textile wastewater treatment processes efficiently.  

When it comes to the effects of treated water on streams, ozone’s improvement in biodegradability and reduction in toxicity are worth noting. 

Testing of treated water for toxicity should consider the impact on this parameter that the treatment process has. There has been evidence that ozonation can process highly toxic wastewater by destroying organic molecules. An example of this is the ozonation of MTBE without adding any additional agents. Furthermore, surfactants must be removed from the water in order to prevent their growth.

Colors as well as surfactants are sometimes found in textile waste water. All dyes used in textile processing can be effectively removed with ozone. Several factors can determine the amount of ozone: the type of dye used, where ozone is used in the process, and how much color is removed in the biological process. In order for an ozone generator to be economically feasible, it is crucial to know how much ozone is needed to remove the desired color from the receiving water body.

According to recent study, 1 mg of ozone is required per mg of dye to remove 95% of the color, although the ratio varies depending on the dye. Approximately 1.5 mg of ozone is required to remove 100% of the dye. It took about 10 minutes for the dye to be removed. In the textile industry, the typical dose after a biological treatment is 15 mg/l, but can easily exceed 25 mg/l.  

Industrial Ozone Generator

Corona discharge is the most common method of converting oxygen to ozone in industrial ozone generators. Wet air, oxygen concentrated from the air, and LOX can all provide oxygen.

Using oxygen allows for a smaller ozone generator for a given production amount and reduces energy requirements. Venturi injectors, for instance, do not require as much energy to mix ozone with water. LOX, including the equipment used to store and evaporate LOX, or the compressed air required for the concentration process, will offset this cost. Oxygen tends to be preferred as the units grow in size.  

Air fed ozone systems for the treatment of textile wastewater include the following components: an air compressor, a dryer, an ozone generator, an ozone water mixing system, and an ozone destroyer.  Electrolytic systems, in general, are probably not economic if they cannot compete with this type of ozone system.

Ozone generators must be operated with dry air in order to succeed. In modern air-fed ozone systems, pressure swing adsorption (PSA) is used with high-pressure air driers. In this scenario, a refrigeration unit and heated desiccant dryer are not needed, but there is an increase in compressor pressure to around 100 psi.

Air and oxygen each make up between 2-3% and 6-10% of the final gas mixed with the water. 

Mixing the gas with water using a venturi or fine bubble diffuser is one method of dissolving ozone. The excess gas in the water must be removed. Injection systems using venturis require a booster pump. In addition to eliminating the booster pump, diffusers could replace the venturi, making it less expensive.

According to another research, the quality of the treatment effluent in terms of color removal depends on several factors, including the color of the feed, the ozone dose, the type of waste water, and the temperature of the waste water. In order to achieve the best results regarding color removal, the wastewater should have been treated earlier in order to lower the values of the other characteristics so that the ozone oxidizing effect is utilized. Moreover, the ideal physical conditions for its solubility are below 30 degrees Celsius. It indicates that adding ozone to the wastewater could give good results even with unprocessed wastewater, provided it is properly cooled. This statement certainly pertains to the practical use of ozone technology in wastewater treatment.

Ozone dissolved in water needs to be allowed to react for a certain period of time in order to become irreversible. Ten to twenty minutes is probably the time needed. This is accomplished by using either a container or tank to hold the solution. The container may also be used to separate the liquid from the gas.  

Bottom Line

All things considered, the ozone generator systems can help with dye color removal in textile processing as well as it can treat wastewater. You can check out our best ozone generators to ozone dye color removal here. Let us know if you have any queries or need any sort of help in choosing the appropriate equipment for your needs.