Wastewater Colour Removal - Water and Wastewater - Water Treatment

The presence of colour in water and wastewater, even a small amount, is highly visible and affects the aesthetic value. Colour is often caused by organic matter. Forms of organic content that cause colour pollution include synthetic chemical dyes, algae species and natural dissolved organics such as lignin and tannins.

Why treat colour in wastewater?

High levels of colour in wastewater have an impact on photosynthesis activity by reducing the penetration of sunlight to lower levels in the water body affecting aquatic life. Standards exist to provide guidance on the safe level of colour that can be discharged to the environment e.g. in the European Economic Community Standard.

Colour can be measured in two ways

The true colour is given by filtering out particulate matter and the apparent colour is without filtration. It is measured in Hazen Units (HU), which is the same as Platinum Cobalt Units (PCU).

Colour affects wastewater safety level for discharge to sewers

To meet a safe level of discharge to the environment, industries have to implement on-site treatment. Colour is not readily removed from microbial-based treatment processes. Therefore, different advanced wastewater treatment technologies should be implemented to remove the remaining hard-to-treat dyes and chemicals.

A working solution

The Arvia ODC combines the well-known advantages of adsorption and advanced oxidation to remove colour in a variety of waste streams. The process uses a unique proprietary adsorbent, NyexTM, which attracts organic contaminants to its surface. An electric current applied oxidises the contaminants, while simultaneously regenerating the Nyex, thus allowing a continuous process to take place. The Arvia technology effectively removes colour in water using no chemicals and leaving no by-products or secondary waste stream.

The Arvia ODC can be used in various industries such as domestic, food-processing, brewage, pharmaceutical and textile production, dredging and downstream processes.