Since color is responsible for many customer complaints about water quality, it is of great concern for drinking water treatment plant operators. Other than drinking water, ozone is being used to remove wastewater color. Fulvic, tannic, and humic acids contribute to many color problems. Some of the conjugated double bonds in these color-causing compounds can be easily split by ozone. Additionally, chlorinated organics can also be formed by these compounds, so their control is important for a number of reasons.
The color of water depends on two factors: dissolved species, such as fulvic acid and humic acid, scattering light, or particulate matter, which scatters light. In order to treat problems associated with particulates, apparent color, and microorganisms, membranes with pores of 0.45 microns are effective.
Conventional Method Vs Ozone
Although conventional treatment processes can remove a substantial amount of color even in cases of dissolved organics, true color, conventional processes (coagulation, flocculation, sedimentation, and filtration) are effective. This service can be performed with activated carbon, but it can have a short life expectancy depending on the level of color.
On the other hand, colors can be effectively oxidized by ozone. For water treatment applications, an ozone generator produces ozone on site and mixes it with water. For fulvic and humic substances, ozone doses of 1-3 mg ozone/mg of carbon can remove color almost completely. (ref: https://www.sciencedirect.com/science/article/abs/pii/0043135486900059) Ozone doses of 1 mg per liter can remove ten color units (CU). However, color measurements are an important concept to understand.
A variety of applications require the use of ozone for the removal or lessening of color caused by hydrocarbons. It is very effective at degrading hydrocarbons that create color. In order to destroy the color, you must determine how much ozone is needed and how to do it most economically.
Several factors affect the amount of ozone required to treat water color, such as the amount of water, the flow of the water or the size of the water storage tank, the amount of bio-load in the water, the hardness of the water, the temperature, etc.
To calculate the exact size of the ozone system, it is important to run a pilot scaled-down on some side stream, whose result allows us to determine ozone’s specific size and effectiveness in your application while at the same time calculating the size of the ozone system.
Using Venturi Injector
The typical way to inject ozone into your water is to use a venturi injector. At the right concentration, ozone can lower your water’s color to the required level.
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